Дисертації з теми "Thermal energy demand forecast"
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1
Thomas, Arthur. "The Econometrics of Energy Demand : identification and Forecast." Thesis, Nantes, 2020. http://www.theses.fr/2020NANT3021.
Повний текст джерелаАнотація:
La prévention du changement climatique est l'une des priorités de la politique énergétique mondiale qui vise à réduire massivement les émissions de gaz à effet de serre. Face à ces défis, il est frappant de constater que notre connaissance de la modélisation de la demande énergétique demeure imparfaite car elle repose en grande partie sur des travaux empiriques anciens et des méthodologies aujourd'hui dépassées. L'objectif scientifique de cette thèse est double : analyser quantitativement les déterminants économiques de la demande énergétique et développer de nouveaux modèles de prévision. Cette thèse est structurée en quatre chapitres. Le premier chapitre montre que la consommation de gaz naturel en France peut être prédite à l'aide d'un modèle simple utilisant seulement les informations disponibles pour les acteurs du marché. Ce chapitre prouve l'existence d'une relation à long terme entre la demande de gaz naturel et les prix des autres énergies et il fournit des estimations de leurs impacts marginaux sur les niveaux de demande observés. Le deuxième chapitre étudie empiriquement le rôle de la température dans la prévision des prix du gaz aux États-Unis. Il développe une méthodologie de construction d’un nouvel indice mensuel basé sur la température. Cet indice capture les variations de la demande résiduelle de gaz naturel en temps réel. Il est utilisé comme variable exogène supplémentaire dans des modèles structurels VAR afin d’améliorer les prévisions ; et nous montrons que ces modèles prédictifs dérivés de modèles structurels sont améliorés en s’appuyant sur des données en temps réelles (non sujettes à révision). Le troisième chapitre propose d’utiliser dans le cas du pétrole, un modèle structurel capturant les anticipations à l’aide de VAR non causaux et d’identifier correctement les réactions des variables clés du pétrole à un choc d’actualité. Le quatrième chapitre réexamine le pouvoir prédictif de la structure par terme des prix, dite « convenience yield », du pétrole et du gaz en intégrant les anticipations dans une spécification empirique, par le biais d’un VAR non causal basé sur la théorie du stockage qui fournit des prévisions de prix très compétitives dans un cadre bivarié simpleThe prevention of climate change is one of the priorities of the world energy policy that aims to massively reduce greenhouse gas emissions. Faced with these challenges, it is striking to note that our knowledge of energy demand modeling remains limited because it is largely based on old empirical work and methodologies that are now dated. Therefore, the objective of our work is twofold. First, we analyze quantitatively the economic determinants of energy demand. Second, we develop new forecasting models. This thesis is structured in four chapters. The first chapter shows that natural gas consumption in France can be predicted using a simple model which only includes public information that is available to market's participants. This chapter proves the existence of a long-term relationship between demand and prices of other energies and provides estimates of their marginal impacts on observed demand levels. The second chapter empirically investigates the role of temperature in forecasting gas prices in the US. It develops a methodology to build a new monthly index based on temperature. This index captures variations in residual demand for natural gas in real time. It is used as an additional exogenous variable in structural models (VAR) to improve forecasts and we show that, in our case, predictive models derived from a structural model are enhanced relying on true real-time (not subject to revisions) data. The third chapter proposes to use, in the case of oil market, a structural model capturing expectations in a noncausal VAR framework, and to properly identify the reactions of oil key variables to supply news shock. The fourth chapter revisits the predictive power of oil and gas convenience yield by incorporating expectations into an empirical specification through non-causal VAR based on the theory of storage which delivers very competitive price predictions in a simple bivariate setting
2
MENDES, EVANDRO LUIZ. "INTERVENTION MODELS TO FORECAST MONTHLY DEMAND OF ELETRIC ENERGY, CONSIDERING THE RATIONING SCENERY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2002. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3336@1.
Повний текст джерелаАнотація:
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICONesta dissertação é desenvolvida uma metodologia para previsão de demanda mensal de energia elétrica considerando cenários de racionamento. A metodologia usada consiste em, a partir das taxas de crescimento da série temporal, identificar e eliminar os efeitos do racionamento de energia elétrica através da aplicação de Modelos Lineares Dinâmicos. São analisadas também estruturas de intervenção nos modelos estatísticos de Box & Jenkins e Holt & Winters. Os modelos são então comparados segundo alguns critérios, basicamente no que tange à sua eficiência preditiva. Conclui-se ao final sobre a eficiência da metodologia proposta, dado a grande dificuldade para solucionar o problema a partir dos modelos estatísticos de Box & Jenkins e Holt & Winters. Esta solução é então proposta como a mais viável para criar cenários de racionamento e pósracionamento de energia para ser utilizado por agentes do sistema elétrico nacional.
In this dissertation, a methodology is developed to forecast monthly demand of electric energy, considering the rationing scenery. The methodology is based on, taking the growth rate from the time series, identify and eliminate the effects of electric energy rationing, using Dynamic Linear Models. It is also analyzed intervention structures in the statistics models of Box & Jenkins and Holt & Winters. The models are compared according to some criterions, mainly forecast accuracy. At the end, we concluded that the methodology proposed is more efficient, due to the difficult to solve the problem using the statistics models with intervention. This solution is proposed as the best among them to create scenery during the energy rationing and after energy rationing, to be used by the national electric system agents.
3
Zhao, Zhiheng. "Thermal Inertia In Residential Buildings For Demand Response." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16018.
Повний текст джерелаАнотація:
A smart home energy management system has been used to reshape the electricity demand of the residential buildings widely. It normally requires understanding the capability of residential buildings’ thermal mass which revisits to the temperature flatirons and providing enough energy buffers. In this project, phase change material (PCM) was used as the virtual thermal energy storage. Basically, two parts were included: thermal modelling of residential building with PCM layer. Secondly thermal behaviour of models under different conditions (heating, ventilation and air conditioning system, fenestration, solar radiation) is discussed. Some numerical methods for thermal modelling with EnergyPlus are also presented. A conduction finite difference algorithm in EnergyPlus are applied to calculate heat transfer between ambient and zone. The results indicate that PCM layers shift and decreased the indoor temperature during peak period. Also, solar radiation and fenestration can influence its performance. A model that is easily scalable in one thermal zone and convex as a function of the control inputs is derived based on energy balance equations. The indoor temperatures are treated as control inputs together with the cooling energy exchange with the virtual thermal storage. This simplifies the enforcement of comfort, which can be imposed through appropriate constraints on the control inputs. A convex constrained optimization program was formulated to address the optimal energy management, in order to minimize the electricity cost caused by Heating, Ventilation and Air Conditioning unit.
4
Cowan, David. "Understanding and modelling thermal energy demand and emissions in urban environments." Thesis, London South Bank University, 2017. http://researchopen.lsbu.ac.uk/1863/.
Повний текст джерелаАнотація:
Refrigeration, air conditioning and heat pump (RACHP) systems currently account for nearly 20% of UK grid electricity use and over 7% of all UK greenhouse gas emissions. This research project has investigated the sources and levels of emissions from RACHP systems and how the cooling (and heating) energy and emissions from buildings might be reduced by optimizing the building’s design, construction and operation. Analysis of data from site surveys and maintenance logs confirmed that leakage of refrigerant can be a significant contributor to total RACHP emissions. TEWI (total equivalent warming impact) analyses showed that for RACHP systems with high GWP (global warming potential) refrigerants and annual leak rates of 10% or more, direct emissions from refrigerant leakage can exceed the indirect emissions associated with energy use. However, for heat pump and air conditioning systems, with typical leak rates of below 3%, using low GWP refrigerants (GWP = 500 or less), the direct emissions do not make a significant contribution to building emissions. A new dynamic energy balance model and Excel based tool were developed to help improve the understanding of building energy use and emissions. The tool can be used to predict the sensitivity to different building design concepts, features and operation and the parameters of the installed RACHP plant. Results for an office building suggest that the building fabric (with the exception of the glazing) is not necessarily a key factor influencing the total energy use and emissions. However, relatively simple measures to reduce electricity use and to reduce solar gain could each reduce building emissions by 10% or more. Results for a dwelling built to 2006 Building Regulations demonstrated an overheating risk in summer, even with mechanical ventilation, but adding a 2 kW air conditioning unit could prevent overheating, with lower energy use and emissions than a similar dwelling incorporating mechanical ventilation. Climate change simulations for the year 2080 predicted a net increase in energy demand and emissions of about 5% for the office building (mainly associated with the use of grid electricity), implying that the grid carbon factor is likely to be a key determinant of future emissions from such buildings. For dwellings without mechanical ventilation or air conditioning, internal temperatures might rise as high as 40°C in summer months, but a small air conditioning unit could maintain temperatures below 25°C with no increase in total energy use and emissions compared with the present day. For a grid electricity carbon factor reduction of 80%, total emissions for the simulated office building would fall by about 70% and for the dwelling by about 50%.
5
Wang, Hao. "Numerical study of cooling demand and thermal performance for different wall constructions." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-19175.
Повний текст джерела
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Sivabavanandan, Sivalingam. "Thermal energy storage application for load shifting and electrical demand management in Saudi Arabia." Thesis, Kingston University, 2005. http://eprints.kingston.ac.uk/35780/.
Повний текст джерелаАнотація:
Energy plays a major role in the economic prosperity of the Middle Eastern countries. Since the region is the largest oil producer of the world, it is less anticipated that these countries would ever be face with an energy crisis similar to the one experienced by the rest of the world during 1970s. The region was going through a chronic electricity demand supply crises with the demand for electrical energy in the rapidly expanding towns, cities and industries, far exceeding the power being made available. The relatively low electrical tariff also contributed to the increasing power demand due to wastage and uneconomical usage of electrical energy. The power generating companies and the Government authorities in the Middle East encouraged scientists and engineers to engage in ambitious Demand Side Management (DSM) programmes to develop novel ideas and new technologies to improve system efficiencies and to reduce energy consumption specifically in the field of refrigeration and air conditioning. The researcher began analysing the potential and possible applications of cool storage as a tool for Demand Side Management (DSM) in central air conditioning systems in the Middle East in 1991. The coupling of a refrigerated water storage tank or an ice storage tank to an air-cooled chiller plant, operated at night for load shifting, electrical peak demand reduction and energy conservation has been the major interest of investigation. The model project commissioned in 1996 used as a typical example to investigate electrical demand management for an office building in Riyadh, Saudi Arabia. The aim of this research was to develop new modified comfort cooling system coupled with a cool storage or commonly known as Thermal Energy Storage (TES) network. The research was expected to establish certain favouring conditions in relation to technical, economical and environmental criteria to make the TES application a viable option in comfort cooling systems in commercial buildings in the Middle East for electrical demand reduction, load shifting and energy conservation.
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Høseggen, Rasmus Z. "Dynamic use of the building structure - energy performance and thermal environment." Doctoral thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1998.
Повний текст джерелаАнотація:
The main objectives of this thesis have been to evaluate how, under which premises, and to what extent building thermal mass can contribute to reduce the net energy demand in office buildings. The thesis also assesses the potential thermal environmental benefits of utilizing thermal mass in office buildings, i.e. reduction of temperature peaks, reduction of temperature swings, and the reduction in the number of hours with excessive operative temperatures. This has been done by literature searches, and experimental and analytical assessments. This thesis mainly concerns office buildings in the Norwegian climate. However, the methods used and the results obtained from this work are transferable to other countries with similar climates and building codes.
Within the limitations of this thesis and based on the findings from all parts and papers this thesis comprises, it is shown that utilization of thermal mass in office buildings reduces the daytime peak temperature, reduces the diurnal temperature swing, decreases the number of hours with excessive temperatures, and increases the ability of a space to handle daytime heat loads. Exposed thermal mass also contributes to decrease the net cooling demand in buildings. However, thermal mass is found to have only a minor influence on the heating demand in office buildings.
The quantity of the achievements is dependent on the amount of exposed thermal mass, night ventilation strategy, and airflow rates. In addition, parameters such as set point temperatures, control ranges, occupancy patterns, daytime ventilation airflow rates, and prevailing convection regimes are influential for the achieved result. The importance of these parameters are quantified and discussed.
Hovedmålene med denne avhandlingen har vært å evaluere hvordan, under hvilke forutsetninger og i hvilken utstrekning termisk masse kan bidra til å redusere netto energibehov i kontorbygninger. Avhandlingen vurderer også hvilke potensielle fordeler termisk masse har for det termiske inneklimaet, dvs. reduksjon av maksimumstemperatur, temperatursvingninger og antall timer med overtemperaturer. Disse undersøkelsene er gjort gjennom søk i litteraturen, feltstudier og analytiske metoder. Avhandlingen omfatter i hovedsak kontorbygninger under norske forhold, men metodene og resultatene er overførbare til andre land med sammenlignbare klimatiske forhold og byggeskikk.
Innenfor avgrensningene gjort i avhandlingen og basert funnene i de ulike delene og artiklene avhandlingen består av, er det vist at utnyttelse av termisk masse i kontorbygg bidrar til å redusere netto energibehov. Termisk masse reduserer også maksimumstemperaturen dagtid, demper temperaturvariasjonene over døgnet og reduserer antall timer med overtemperaturer. Utnyttelse av termisk masse bidrar også til at rom kan tåle en høyere intern varmelast enn lette rom uten at dette går ut over den termiske komforten. Termisk masse har imidlertid liten betydning for energibehovet for oppvarming i kontorbygg.
Gevinsten med å utnytte termisk masse avhenger av tilgjengeligheten av eksponerte tunge materialer, strategi for nattventilasjon og ventilasjonsluftmengder. I tillegg innvirker parametere som settpunkttemperaturer, dødbånd og kontrollintervaller for ventilasjonen og bruksmønster. Innvirkningen av disse parametrene er diskutert og kvantifisert.
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Olsson, Martin. "Thermal Shape Factor : The impact of the building shape and thermal properties on the heating energy demand in Swedish climates." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-125076.
Повний текст джерелаАнотація:
In the year 2006, the energy performance directive 2002/91/EG was passed by the European Union, according to this directive the Swedish building code was supplemented by a key measure of energy use intensity (EUI). The implemented EUI equals some energy use within a building divided by its floor area and must be calculated in new housing estate and shown when renting or selling housing property. In order to improve the EUI, energy efficiency refurbishments could be implemented. Building energy simulation tools enables a virtual view a building model and can estimate the energy use before implementing any refurbishments. They are a powerful resource when determine the impact of the refurbishment measure. In order to obtain a correct model which corresponds to the actual energy use, some adjustments of the model are often needed. This process refers to as calibration. The used EUI has been criticized and thus, the first objective in this work was to suggest an alternative key measure of a buildings performance. The results showed that the currently used EUI is disfavoring some districts in Sweden. New housing estate in the far north must take more refined actions in order to fulfill the regulation demand, given that the users are behaving identical regardless where the house is located. Further, the suggested measure is less sensitive to the users’ behavior than the presently used EUI. It also has a significance meaning in building design as it relating the building shape and thermal properties and stating that extreme building shapes must undergo a stricter thermal construction rather than buildings that are more compact. Thus, the suggested key measure also creates a communication link between architects and the consultant constructors. The second objective of this thesis has been to investigate a concept of calibration using the data normally provided by energy bills, i.e. some monthly aggregated data. A case study serves to answer this objective, by using the building energy simulation tool IDA ICE 4.7 and a building located in Umeå, Sweden. The findings showed that the used calibration approach yielded a model considered as calibrated in eleven of twelve months. Furthermore, the method gives a closer agreement to the actual heat demand rather than using templates and standardized values. The major explanation of the deviation was influence of the users, but also that the case study building burden with large heat losses by domestic hot water circulation and thus, more buildings should be subjected to this calibration approach.
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Kettenis, Christos. "Electrical supply and demand in Cyprus : optimal use of renewable energy sources in electricity production." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/electrical-supply-and-demand-in-cyprus-optimal-use-of-renewable-energy-sources-in-electricity-production(3861cfcb-8a74-4087-a114-4e0dc9557202).html.
Повний текст джерелаАнотація:
As fossil fuel usage has been proven to have a negative impact on human health and the environment, the world has embraced the usage of renewable energy sources, mainly for energy production. In Cyprus, solar energy is the most potent renewable source and this can be seen by the vast majority of the population using solar water heaters in their households. This thesis explores the usage of solar energy for electricity and domestic hot water production at a residential level by presenting the designs of three solar-thermal concept systems for achieving this task; the first being the basic design of all three without any form of storage, the second is fitted with thermal latent heat storage and the third is fitted with a natural gas boiler instead. The optimal solution is the second concept system that is capable of storing thermal energy around the year thus having a nearly uninterrupted operation, reducing the dependency on fossil fuel produced electricity and emissions. The thesis also explored the usage of siloxane organic compounds as working fluids for a low temperature Rankine cycle, which had a significant impact in the increase of the thermal-to-electrical efficiency of the cycle, raising it to nearly 25%, greater than the efficiency of best acclaimed photovoltaic collector currently available. Lastly, taking into account a typical household’s demand profile and by allowing the optimal system to operate as part of the national electrical network continuously, the size of the system’s components could be reduced significantly making it more feasible for installing in a typical household’s premises. However, due to the non-existence of these components in the within the project’s specifications, the thesis could not include a useful economic analysis for a more realistic comparison with a similar sized photovoltaic system.
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Motuzienė, Violeta. "Complex analysis of the influence of glazing on energy demand of public buildings." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20101228_125700-05528.
Повний текст джерелаАнотація:
Applying building energy simulations, the dissertation investigates the issu-es of energy efficiency of public buildings. The main object of research – influence of the glazing of the public building on its energy demand. Next to its main function to ensure daylighting, glazing must to be energy efficient. So these requirements conflict.
The aim of this dissertation is to perform the complex analysis of the influence of glazing characteristics on the building‘s microclimate and lighting systems energy demand, taking into account DL demand. Also define, what glazing characteristics in Lithuanian and similar climate countries, are able to decrease buildings energy demand to the level of the low energy building. The paper approaches two major tasks. Task 1 is performance of the detailed analysis of influence of glazing on energy demand of the public building. Task 2 is determination of the efficient glazing characteristics of the energy efficient building.
The dissertation consists of Introduction, 4 chapters, Conclusions, references and list of published works of the author on the topic of dissertation.
The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the paper, research methodology, scientific novelty, the practical significance of results examined in the paper and defended statements. The introduction ends in presenting the author’s publications on the subject of the defended... [to full text]Disertacijoje, taikant dinaminį pastatų energijos poreikių modeliavimą, nag-rinėjamos viešosios paskirties pastatų energinio efektyvumo problemos. Pagrin-dinis tyrimo objektas yra viešosios paskirties pastato fasado įstiklinimo įtaka energijos poreikiams. Greta savo pagrindinės funkcijos – pakankamo natūralaus apšvietimo užtikrinimo, fasado įstiklinimas privalo būti energiškai efektyvus. Tai prieštaringi reikalavimai. Pagrindinis disertacijos tikslas – įvertinant natūralaus apšvietimo poreikį, kompleksiškai išanalizuoti viešosios paskirties pastato įstiklinimo charakteristi-kų įtaką pastato mikroklimato ir apšvietimo sistemų energijos poreikiams bei nustatyti, kokioms pastato įstiklinimo charakteristikoms esant, Lietuvoje bei pa-našaus klimato šalyse pastato energijos poreikius galima būtų sumažinti iki ma-žai energijos vartojančio pastato lygio. Darbe sprendžiami du pagrindiniai užda-viniai: pirmasis – atliekama įstiklinimo įtakos kondicionuojamo pastato energijos poreikiams analizė; antrasis – nustatomos efektyvios energiškai efek-tyvaus pastato įstiklinimo charakteristikos. Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, apra-šomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai, pristatomos... [toliau žr. visą tekstą]
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Abedin, Joynal. "Thermal energy storage in residential buildings : a study of the benefits and impacts." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25520.
Повний текст джерелаАнотація:
Residential space and water heating accounts for around 13% of the greenhouse gas emissions of the UK. Reducing this is essential for meeting the national emission reduction target of 80% by 2050 from the 1990 baseline. One of the strategies adopted for achieving this is focused around large scale shift towards electrical heating. This could lead to unsustainable disparity between the daily peak and off-peak electricity loads, large seasonal variation in electricity demands, and challenges of matching the short and long term supply with the demands. These challenges could impact the security and resilience of UK electricity supply, and needs to be addressed. Rechargeable Thermal Energy Storage (TES) in residential buildings can help overcome these challenges by enabling Heat Demand Shifts (HDS) to off-peak times, reducing the magnitude of the peak loads, and the difference between the peak and off-peak loads. To be effective a wide scale uptake of TES would be needed. For this to happen, the benefits and impacts of TES both for the demand side and the supply side have to be explored, which could vary considerably given the diverse physical, thermal, operational and occupancy characteristics of the UK housing stock. A greater understanding of the potential consequence of TES in buildings is necessary. Such knowledge could enable appropriate policy development to help drive the uptake of TES or to encourage development of alternative solutions. Through dynamic building simulation in TRNSYS, this work generated predictions of the space and water heating energy and power demands, and indoor temperature characteristics of the UK housing stock. Twelve building archetypes were created consisting of: Detached, semi-detached, mid-terrace and flat built forms with thermal insulation corresponding to the 1990 building regulation, and occupied floor areas of 70m2, 90m2 and 150m2. Typical occupancy and operational conditions were used to create twelve Base Case scenarios, and simulations performed for 60 winter days from 2nd January. HDS of 2, 3 and 4 hours from the grid peak time of 17:00 were simulated with sensible TES system sizes of 0.25m3, 0.5m3 and 0.75m3, and water storage temperatures of 75°C and 95°C. Parametric analysis were performed to determine the impacts and benefits of: thermal insulation equivalent to 1980, 1990 (Base Case), 2002 and 2010 building regulation; locations of Gatwick (Base Case) and Aberdeen; heating durations of 6, 9 (Base Case), 12 and 16 hours per day; thermostat settings of 19°C, 21°C (Base Case) and 23°C, and number of occupiers of 1 person and 3 persons (Base Case) per household. Good correlation was observed between the simulated results and published heat energy consumption data for buildings with similar thermal, physical, occupancy and operational conditions. The results allowed occupied space temperatures and overall daily and grid peak time energy consumption to be predicted for the range of building archetypes and parameter values considered, and the TES size necessary for a desired HDS to be determined. The main conclusions drawn include: The overall daily energy consumption predictions varied from 36.8kWh to 159.7kWh. During the critical grid peak time (17:00 to 21:00) the heat consumption varied from 4.2kWh to 58.7kWh, indicating the range of energy demands which could be shifted to off-peak times. On average, semi-detached, mid-terrace, and flat built forms consumed 7.0%, 13.8% and 22.7% less energy for space heating than the detached built form respectively. Thermal insulation changing from the 1990 building regulation level to the 1980 and 2010 building regulation levels could change the mean energy use by +14.7% and -19.6% respectively. A 0.25m3 TES size with 75°C water storage temperature could enable a 2 hour HDS, shifting 4.3kWh to 11.7kWh (mean 8.7kWh) to off peak times, in all 70m2 Base Case archetypes with the 60 day mean thermal comfort of 100%, but with the minimum space temperature occasionally dropping below an 18°C thermal comfort limit. A 0.5m3 TES size and water storage of 95°C could allow a 3 hour HDS, shifting 9.8kWh to 28.2kWh (mean 18.7kWh) to off peak times, in all 90m2 Base Case archetypes without thermal comfort degradation below 18°C. A 0.75m3 TES with a 95°C water temperature could provide 4 hour HDS, shifting 13.9kWh to 47.7kWh (mean 27.2kWh) to off peak times, in all 150m2 Base Case archetypes with 100% mean thermal comfort but with the 60 day minimum temperature occasionally dropping below the 18°C thermal comfort limit in the detached built form. Improving the thermal insulation of the buildings was found to be the best way to improve the effectiveness of HDS with TES, in terms of the demand shift period achievable with minimal thermal comfort impact. A 4 hour HDS with 100% thermal comfort is possible in all 90m2 floor area buildings with a 0.25m3 tank and a water storage temperature of 75°C provided that the thermal insulation is as per 2010 building regulation. Recommendations for further research include: 1) creating larger number of archetype models to reflect the housing stock; 2) using heat pumps as the heat source so that the mean effect on the grid from electric heating loads can be predicted; 3) taking into account the costs associated with taking up HDS with TES, in terms of capital expenses and space requirement for housing the TES system; 4) considering alternative methods of heat storage such as latent heat storage to enhance the storage capacity per unit volume; and 5) incorporating zonal temperature control, for example, only heating rooms that are occupied during the demand shift period, which could ensure better thermal comfort in the occupied space and extend the demand shift period.
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Faccani, Alice. "Modeling and validation of the thermal behavior of buildings for the development of demand response methods." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10651/.
Повний текст джерелаАнотація:
The representation of the thermal behaviour of the building is achieved through a relatively simple dynamic model that takes into account the effects due to the thermal mass of the building components. The model of a intra-floor apartment has been built in the Matlab-Simulink environment and considers the heat
transmission through the external envelope, wall and windows, the internal thermal masses, (i.e. furniture, internal wall and floor slabs) and the sun gain due to opaque and see-through surfaces of the external envelope. The simulations results for the entire year have been compared and the model validated, with the
one obtained with the dynamic building simulation software Energyplus.
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Pragada, Gandhi, and Nitish Perisetla. "Utility-Scale Solar Power Plants with Storage : Cost Comparison and Growth Forecast Analysis." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-301838.
Повний текст джерелаАнотація:
Renewable energy for energy production, like Solar, is turning out to be very pertinent in today's world [1]. It is very clear that Solar Energy is going to emerge as one of the key sources of energy in future. Moreover, the storage option is going to play an essential role to the future deployment of solar power plants. Concentrated solar power plants with thermal storage, photovoltaic plants integrated with battery energy storage, and hybrid plants are attractive solutions to obtain a stable and dispatchable energy production. Investors or policymakers usually find it challenging to come up with the most feasible solar storage technology because they need to consider techno-economic feasibility, and at the same time, from a market or administrative perspective as well. So, this thesis study will address the key problem which is aimed at investors or policymakers since there is a need to choose the best solar storage technology at a utility level in future based on so many attributes. The thesis project was carried out in two phases which includes forecast modelling & estimations and techno-economic assessment of virtual plants. These two phases helped to address various questions in relation to the problem statement of this study. The entire thesis study broadly covered seven countries spanning across four major regions around the world. The first phase of the thesis, forecast modelling estimations shows how the seven countries will look in future (2020 – 2050) with respect to installed capacity and costs for PV, CSP, and BESS technologies. Some major results from phase 1 include, in low-cost estimates, China will remain to be the market leader in PV & CSP by 2050. In U.S.A and India, the installed costs of PV are projected to decline by 70% by 2050. By 2050, the installed costs of Solar Tower technology are estimated to drop by about 65% in China and Spain. In U.S.A, the prices of BESS technology are likely to fall by around 58 – 60 % by 2050. In the second phase of thesis study, a techno-economic evaluation of virtual plants addressed the aspects which are to be considered for a solar project if it is deployed in future across seven specific countries. Results from this analysis helps investors or policymakers to choose the cheapest solar storage technology at a utility level across seven specific countries in future (2020 – 2050). Key results from this analysis show that, in the U.S.A, by 2050, PV+BESS will be the cheapest storage technology for 4 – 10 storage hours. Addition of another renewable technology will add up more viability to the comparison. In China, Hybrid will be the cheapest storage technology for 4 – 8 hrs by 2050. There is huge potential for deployment of CSP & hybrid plants in future than PV. In South Africa, CSP will be the cheapest storage technology by 2050 for 4 – 10 hours of storage. It is assumed that deployment of BESS projects at utility level starts from 2025 in South Africa. Beyond this, market forces analysis was carried out which offers insights especially for the policymakers of how various drivers and constraints are influencing each solar technology across the specific countries in future. Overall, the entire thesis study provides guidelines/insights to investors or policy makers for choosing the best solar storage technology in future at a utility scale for a particular country.Förnybar energi för energiproduktion, liksom Solar, visar sig vara mycket relevant i dagens värld [1]. Det är mycket tydligt att solenergi kommer att framstå som en av de viktigaste energikällorna i framtiden. Dessutom kommer lagringsalternativet att spela en väsentlig roll för den framtida distributionen av solkraftverk. Koncentrerade solkraftverk med värmelagring, solcellsanläggningar integrerade med batterilagring och hybridanläggningar är attraktiva lösningar för att få en stabil och skickbar energiproduktion. Investerare eller beslutsfattare brukar tycka att det är utmanande att komma på den mest genomförbara solcellstekniken eftersom de måste överväga teknikekonomisk genomförbarhet, och samtidigt, ur ett marknads- eller administrativt perspektiv också. Så denna avhandlingsstudie kommer att ta itu med nyckelproblemet som riktar sig till investerare eller beslutsfattare eftersom det finns ett behov av att välja den bästa solenergilagringstekniken på en användningsnivå i framtiden baserat på så många attribut. Avhandlingsprojektet genomfördes i två faser som inkluderar prognosmodellering och uppskattningar och teknikekonomisk bedömning av virtuella anläggningar. Dessa två faser hjälpte till att ta itu med olika frågor i samband med problemstudien i denna studie. Hela avhandlingsstudien omfattade i stort sju länder som sträcker sig över fyra stora regioner runt om i världen. Den första fasen i avhandlingen, prognosmodelleringsuppskattningar visar hur de sju länderna kommer att se ut i framtiden (2020 - 2050) med avseende på installerad kapacitet och kostnader för PV-, CSP- och BESS -teknik. Några viktiga resultat från fas 1 inkluderar, i lågkostnadsuppskattningar, att Kina kommer att vara marknadsledande inom PV och CSP år 2050. I USA och Indien beräknas de installerade kostnaderna för PV minska med 70% år 2050. Av 2050 beräknas de installerade kostnaderna för Solar Tower -teknik sjunka med cirka 65% i Kina och Spanien. I USA kommer priserna på BESS -teknik sannolikt att sjunka med cirka 58 - 60 % år 2050. I den andra fasen av avhandlingsstudien behandlade en teknikekonomisk utvärdering av virtuella anläggningar de aspekter som ska övervägas för ett solprojekt om det används i framtiden i sju specifika länder. Resultaten från denna analys hjälper investerare eller beslutsfattare att välja den billigaste solenergilagringstekniken på en användningsnivå i sju specifika länder i framtiden (2020 - 2050). Viktiga resultat från denna analys visar att i USA, år 2050, kommer PV+BESS att vara den billigaste lagringstekniken på 4 - 10 lagringstimmar. Tillägg av en annan förnybar teknik kommer att öka jämförbarheten. I Kina kommer Hybrid att vara den billigaste lagringstekniken i 4-8 timmar fram till 2050. Det finns en enorm potential för distribution av CSP & hybridanläggningar i framtiden än PV. I Sydafrika kommer CSP att vara den billigaste lagringstekniken år 2050 för 4 - 10 timmars lagring. Det antas att distributionen av BESS -projekt på verktygsnivå börjar från 2025 i Sydafrika. Utöver detta genomfördes marknadskravsanalys som ger insikter speciellt för beslutsfattarna om hur olika drivkrafter och begränsningar påverkar varje solteknik i de specifika länderna i framtiden. Sammantaget ger hela avhandlingsstudien riktlinjer/insikter till investerare eller beslutsfattare för att välja den bästa solenergitekniken i framtiden i en nyttoskala för ett visst land.
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Geyser, Martinus Fredrik. "A new integrated procedure for energy audits and analyses of buildings / M.F. Geyser." Thesis, North-West University, 2003. http://hdl.handle.net/10394/414.
Повний текст джерелаАнотація:
A rapid growth in the national electricity demand is placing an ever-increasing demand on the
national electricity supply utility, Eskom. Projections show that the load demand in South Africa
may exceed the installed capacity by as early as 2007. This is mainly due to the increase in
demand in the residential sector as a result of the electrification of rural and previously
disadvantaged communities. However, the industrial and commercial sectors also have a role in
this increase.
In an attempt to reduce the demand for electricity Eskom has adopted its Demand Side
Management (DSM) initiative. This initiative is aimed at lowering the electricity demand in
peak times through energy efficiency (EE) or load shift, out of peak demand times. Eskom is
implementing the DSM strategy by financing Energy Service Companies (ESCOs) to reduce the
demand load of major electricity end-users during peak times.
Buildings consume a large percentage of the total energy supply in the world. Most of the
energy consumed in buildings is used by the heating, ventilation and air-conditioning (HVAC)
systems, as well as lighting. However, a large potential for energy savings exists in buildings.
Studies have shown that up to 70% of the electricity consumption of a building can be saved
through retrofit studies.
However, to capitalise on these opportunities, the ESCOs require tools and procedures that
would enable them to accomplish energy savings studies quickly and efficiently. It should be a
holistic approach to the typical ESCO building audit. A study of current available software
programs showed the lack of holistic tools aimed specifically at retrofit audits, and therefore also
the need for such a program.
The building simulation program most suited to the retrofit study was chosen and it was used in a
retrofit audit. By emulating a retrofit audit with this software, its performance in the field, both
positive and negative, could be established. With the experience gained from the retrofit study,
as well as input from ESCOs in the industry, a need for such a retrofit tool was established.
The simulation program that was tested in the retrofit study is the tool Quickcontrol, as well as
the newer version of the program, entitled QEC. The case study showed that even though these
packages are well suited to ESCO work, they have certain drawbacks in view of the holistic
project approach. The ESCOs require a simple, fast, and integrated procedure for energy audits.
This procedure should be embodied in a software program.
This study proposes a new integrated procedure for energy audits and the analyses of buildings,
in the form of a software tool. This new tool is geared towards the ESCO building audit, in both
South A6ica and internationally. It is designed to enable a diplomate engineer to accomplish a
building energy and retrofit analysis in two weeks, leading the user through all the main project
steps, from data acquisition to writing of the final project report. This is a significant
improvement, since it normally takes 50 man-days for an experienced and trained engineering
team to complete a full building audit.
This tool was used in a case study to test its validity and accuracy. It was found that certain
situations would arise in which the criteria that were set for the program would not be adequate.
The results from the case study were favourable and satisfied the criteria that were set for the
procedure.Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.
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Joševski, Martina Verfasser], Dirk [Akademischer Betreuer] [Abel, and Jakob Lukas [Akademischer Betreuer] Andert. "Predictive energy management of hybrid electric vehicles with uncertain torque demand forecast for on-road operation / Martina Joševski ; Dirk Abel, Jakob Lukas Andert." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1189332698/34.
Повний текст джерела
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Elhashmi, Rodwan. "Comprehensive Study Toward Energy Opportunity for Buildings Considering Potentials for Using Geothermal and Predicting Chiller Demand." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1589332482268134.
Повний текст джерела
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Manikonda, Nikhil. "Performance of Deep Geothermal Energy Systems." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23219.
Повний текст джерелаАнотація:
Geothermal energy is an important source of clean and renewable energy. This project deals with the study of deep geothermal power plants for the generation of electricity. The design involves the extraction of heat from the Earth and its conversion into electricity. This is performed by allowing fluid deep into the Earth where it gets heated due to the surrounding rock. The fluid gets vaporized and returns to the surface in a heat pipe. Finally, the energy of the fluid is converted into electricity using turbine or organic rankine cycle (ORC). The main feature of the system is the employment of side channels to increase the amount of thermal energy extracted. A finite difference computer model is developed to solve the heat transport equation. The numerical model was employed to evaluate the performance of the design. The major goal was to optimize the output power as a function of parameters such as thermal diffusivity of the rock, depth of the main well, number and length of lateral channels. The sustainable lifetime of the system for a target output power of 2 MW has been calculated for deep geothermal systems with drilling depths of 8000 and 10000 meters, and a financial analysis has been performed to evaluate the economic feasibility of the system for a practical range of geothermal parameters. Results show promising an outlook for deep geothermal systems for practical applications.
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Gils, Hans Christian [Verfasser], and André [Akademischer Betreuer] Thess. "Balancing of intermittent renewable power generation by demand response and thermal energy storage / Hans Christian Gils. Betreuer: André Thess." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2016. http://d-nb.info/1081367563/34.
Повний текст джерела
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Baniasadi, Ali. "Application of heat pumps and thermal storage systems for improved control and performance of microgrids." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2020. https://ro.ecu.edu.au/theses/2316.
Повний текст джерелаАнотація:
The high penetration of renewable energy sources (RES), in particular, the rooftop photovoltaic (PV) systems in power systems, causes rapid ramps in power generation to supply load during peak-load periods. Residential and commercial buildings have considerable potential for providing load exibility by exploiting energy-e_cient devices like ground source heat pump (GSHP). The proper integration of PV systems with the GSHP could reduce power demand from demand-side. This research provides a practical attempt to integrate PV systems and GSHPs e_ectively into buildings and the grid. The multi-directional approach in this work requires an optimal control strategy to reduce energy cost and provide an opportunity for power trade-o_ or feed-in in the electricity market. In this study, some optimal control models are developed to overcome both the operational and technical constraints of demand-side management (DSM) and for optimum integration of RES.
This research focuses on the development of an optimal real-time thermal energy management system for smart homes to respond to DR for peak-load shifting. The intention is to manage the operation of a GSHP to produce the desired amount of thermal energy by controlling the volume and temperature of the stored water in the thermal energy storage (TES) while optimising the operation of the heat distributors to control indoor temperature.
This thesis proposes a new framework for optimal sizing design and real-time operation of energy storage systems in a residential building equipped with a PV system, heat pump (HP), and thermal and electrical energy storage systems. The results of this research demonstrate to rooftop PV system owners that investment in combined TSS and battery can be more profitable as this system can minimise life cycle costs.
This thesis also presents an analysis of the potential impact of residential HP systems into reserve capacity market. This research presents a business aggregate model for controlling residential HPs (RHPs) of a group of houses that energy aggregators can utilise to earn capacity credits. A control strategy is proposed based on a dynamic aggregate RHPs coupled with TES model and predicting trading intervals capacity requirements through forecasting demand and non-scheduled generation. RHPs coupled with TES are optimised to provide DSM reserve capacity. A rebound effect reduction method is proposed that reduces the peak rebound RHPs power.
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Lumbier, Fernandez Mikel. "Alternative energy supply study for a cottage in Vifors." Thesis, Högskolan i Gävle, Energisystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-26714.
Повний текст джерелаАнотація:
The present master thesis was done during the spring of 2018. A cottage located in Vifors is studied with regard to its heating requirements. At the time of the study, the house could not be inhabited the whole year because there was no tap hot water available and the space heating demand was covered by electricity. Thus, an alternative heating supply is required to be developed. As a strategic prerequisite, the solution should be achieved considering both solar thermal collectors and a heat pump.First, the characteristics of the building were collected/determined in order to obtain the total heating demand per month and hence annually. Parameters such as the U-values, roof orientation, room dimensions, ventilation rates and internal gains were required to configure the building model in the software IDA ICE 4.8. In addition, the amount of tap hot water required per year was determined as 17 m3 per year. Cold water at 5 °C had to be heated until 55 °C to obtain the tap hot water.Once the heating requirements were known, the most suitable solution was to use a combi system (solar thermal collectors and a heat pump). Solar energy could fulfil the demand in the summer and the heat pump provided energy in the winter. For a commercial model of the flat solar thermal collector (Vitosol 100-F) the solar system was sized according to the heating demand in the summer time. The maximum energy that could be obtained from the solar collectors in summer was calculated, the rest of the demand had to be fulfilled by a heat pump, model WPL-18 E.The achieved solution is compounded by the heat pump and 3 solar thermal collectors with a surface of 2.33 m2 each. The solar energy obtained is 1 843 kWh per year, which covers 9 % of the total annual heating demand (20 098 kWh). However, the 98 % of the heating demand during the summertime comes from the solar collectors. The investment cost is 113 900 SEK and the payback period is estimated in 8 years.
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Raillon, Loic. "Experimental identification of physical thermal models for demand response and performance evaluation." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI039.
Повний текст джерелаАнотація:
La stratégie de l’Union Européenne pour atteindre les objectifs climatiques, est d’augmenter progressivement la part d’énergies renouvelables dans le mix énergétique et d’utiliser l’énergie plus efficacement de la production à la consommation finale. Cela implique de mesurer les performances énergétiques du bâtiment et des systèmes associés, indépendamment des conditions climatiques et de l’usage, pour fournir des solutions efficaces et adaptées de rénovation. Cela implique également de connaître la demande énergétique pour anticiper la production et le stockage d’énergie (mécanismes de demande et réponse). L’estimation des besoins énergétiques et des performances énergétiques des bâtiments ont un verrou scientifique commun : l’identification expérimentale d’un modèle physique du comportement intrinsèque du bâtiment. Les modèles boîte grise, déterminés d’après des lois physiques et les modèles boîte noire, déterminés heuristiquement, peuvent représenter un même système physique. Des relations entre les paramètres physiques et heuristiques existent si la structure de la boîte noire est choisie de sorte qu’elle corresponde à la structure physique. Pour trouver la meilleure représentation, nous proposons d’utiliser, des simulations de Monte Carlo pour analyser la propagation des erreurs dans les différentes transformations de modèle et, une méthode de priorisation pour classer l’influence des paramètres. Les résultats obtenus indiquent qu’il est préférable d’identifier les paramètres physiques. Néanmoins, les informations physiques, déterminées depuis l’estimation des paramètres, sont fiables si la structure est inversible et si la quantité d’information dans les données est suffisante. Nous montrons comment une structure de modèle identifiable peut être choisie, notamment grâce au profil de vraisemblance. L’identification expérimentale comporte trois phases : la sélection, la calibration et la validation du modèle. Ces trois phases sont détaillées dans le cas d’une expérimentation d’une maison réelle en utilisant une approche fréquentiste et Bayésienne. Plus précisément, nous proposons une méthode efficace de calibration Bayésienne pour estimer la distribution postérieure des paramètres et ainsi réaliser des simulations en tenant compte de toute les incertitudes, ce qui représente un atout pour le contrôle prédictif. Nous avons également étudié les capacités des méthodes séquentielles de Monte Carlo pour estimer simultanément les états et les paramètres d’un système. Une adaptation de la méthode de prédiction d’erreur récursive, dans une stratégie séquentielle de Monte Carlo, est proposée et comparée à une méthode de la littérature. Les méthodes séquentielles peuvent être utilisées pour identifier un premier modèle et fournir des informations sur la structure du modèle sélectionnée pendant que les données sont collectées. Par la suite, le modèle peut être amélioré si besoin, en utilisant le jeu de données et une méthode itérativeThe European Union strategy for achieving the climate targets, is to progressively increase the share of renewable energy in the energy mix and to use the energy more efficiently from production to final consumption. It requires to measure the energy performance of buildings and associated systems, independently of weather conditions and user behavior, to provide efficient and adapted retrofitting solutions. It also requires to known the energy demand to anticipate the energy production and storage (demand response). The estimation of building energy demand and the estimation of energy performance of buildings have a common scientific: the experimental identification of the physical model of the building’s intrinsic behavior. Grey box models, determined from first principles, and black box models, determined heuristically, can describe the same physical process. Relations between the physical and mathematical parameters exist if the black box structure is chosen such that it matches the physical ones. To find the best model representation, we propose to use, Monte Carlo simulations for analyzing the propagation of errors in the different model transformations, and factor prioritization, for ranking the parameters according to their influence. The obtained results show that identifying the parameters on the state-space representation is a better choice. Nonetheless, physical information determined from the estimated parameters, are reliable if the model structure is invertible and the data are informative enough. We show how an identifiable model structure can be chosen, especially thanks to profile likelihood. Experimental identification consists of three phases: model selection, identification and validation. These three phases are detailed on a real house experiment by using a frequentist and Bayesian framework. More specifically, we proposed an efficient Bayesian calibration to estimate the parameter posterior distributions, which allows to simulate by taking all the uncertainties into account, which is suitable for model predictive control. We have also studied the capabilities of sequential Monte Carlo methods for estimating simultaneously the states and parameters. An adaptation of the recursive prediction error method into a sequential Monte Carlo framework, is proposed and compared to a method from the literature. Sequential methods can be used to provide a first model fit and insights on the selected model structure while the data are collected. Afterwards, the first model fit can be refined if necessary, by using iterative methods with the batch of data
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Simmons, Cody Ryan. "Proactive Energy Optimization in Residential Buildings with Weather and Market Forecasts." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7594.
Повний текст джерелаАнотація:
This work explores the development of a home energy management system (HEMS) that uses weather and market forecasts to optimize the usage of home appliances and to manage battery usage and solar power production. A Moving Horizon Estimation (MHE) application is used to find the unknown home model parameters. These parameters are then updated in a Model Predictive Controller (MPC) which optimizes and balances competing comfort and economic objectives. Combining MHE and MPC applications alleviates model complexity commonly seen in HEMS by using a lumped parameter model that is adapted to fit a high-fidelity model. HVAC on/off behaviors are simulated by using Mathematical Program with Complementary Constraints (MPCCs) and solved in near real-time with a nonlinear solver. Removing HVAC on/off as a discrete variable decreases potential solutions and consequently reduces solve time and increases the probability of reaching a more optimal solution. The results of this work indicate that energy management optimization significantly decreases energy costs and balances energy usage more effectively throughout the day compared to a home with regular temperature control. A case study for Phoenix, Arizona shows an energy reduction of 21% and a cost reduction of 40%. Homes using this home energy optimization will contribute less to the grid peak load and therefore, improve grid stability and reduce the amplitude of load following cycles for utilities. This case study combines renewable energy, energy storage, forecasts, cooling system, variable rate electricity plan and a multi-objective function allowing for a complete home energy optimization assessment. There remain several challenges, including improved forecast models, improved computational performance to allow the algorithms to run in real-time, and mixed empirical / first principles machine learning methods to guide the model structure.
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CIARROCCHI, ELEONORA. "Demand Side Management in the built environment by means of heat pumps." Doctoral thesis, Università Politecnica delle Marche, 2017. http://hdl.handle.net/11566/245458.
Повний текст джерелаАнотація:
Il Demand Side Management (DSM) raggruppa un insieme di pratiche ed attività progettate per influenzare la domanda energetica di un consumatore in termini di tempo e/o distribuzione con il fine di individuare come utilizzare l’energia elettrica in modo più efficiente. Il DSM diminuisce il costo per il soddisfacimento della richiesta del consumatore in termini energetici tramite investimenti in efficienza energetica e in gestione dei carichi del consumatore, fornendo flessibilità e riconfigurando il mercato dell'elettricità. Gli obiettivi del DSM sono vari ed includono la diminuzione delle emissioni di CO2 nonché un uso più efficiente di energia, inoltre le misure del DSM mirano ad instaurare un sistema più stabile di tariffazione elettrica. Un altro fondamentale obiettivo del DSM è la gestione dei carichi elettrici, ovvero dei profili di carico del consumatore. Le combinazioni tra i profili di carico sono molte e svariate, tra le categorie più impiegate troviamo il Load Shifting ed il Peak Clipping poiché sono di semplice applicazione e realizzazione, inoltre non richiedono l'impiego di tecnologie avanzate. Per questo motivo, questi due profili di carico sono stati i più indagati nei lavori presentati nel manoscritto. Tra le opportunità più interessanti dell'applicazione del DSM troviamo l'impiego di tali strategie nei dispositivi elettrici, per citarne uno tra tanti, nel campo delle pompe di calore. Il modo più promettente di combinare queste due realtà consiste nell'applicare strategie di load management. A tal fine, ci si serve di strumenti in grado di consentire la gestione dei carichi energetici: tra i tanti, uno dei più validi è sicuramente lo stoccaggio di energia termica (TES). Nei programmi di DSM, il TES viene impiegato in modo da spostare la richiesta per il riscaldamento/raffrescamento dai periodi di maggiore richiesta (on-peak) notoriamente più gravosi a livello economico, ai periodi di bassa richiesta (off-peak) dove solitamente la tariffa oraria è più conveniente. L'impiego dei TES nel DSM aggiunge flessibilità alla gestione dei carichi energetici come ampliamente dimostrato da un vasto numero di lavori in letteratura ed è il nostro campo di ricerca. La novità di quanto qui presentato consiste nell'applicazione delle strategie di DSM al settore dell'edilizia residenziale ed industriale, nello specifico applicando il DSM a casi reali nei quali fossero integrate energie rinnovabili. Si parte dal ricostruire il caso reale in un ambiente di simulazione dinamica per simularne il comportamento sul lungo periodo. I modelli di simulazione sono stati progettati per studiare l'integrazione delle strategie di DSM negli edifici e per analizzare gli effetti dei carichi termici sui consumi elettrici e sulle prestazioni degli involucri. I risultati avuti confermano come le strategie di DSM possano agire positivamente sulle prestazioni degli edifici e dell'intero sistema, incrementandone flessibilità ed efficienza energetica. Inoltre, tali strategie di DSM hanno influito sulla riduzione dei consumi energetici e delle bollette elettriche dei casi studiati, soprattutto qualora siano in atto tariffe elettriche che variano su scala oraria, tutto ciò senza intaccare il comfort interno degli edifici e degli occupanti. Le strategie di DSM risultano essere economicamente vantaggiose qualora vengano integrati sistemi di stoccaggio di energia termica; questi permettono di spostare la richiesta energetica nelle fasce orarie di bassa tariffazione, andando ad attivarsi nei periodi di on-peak, ovvero quando il costo dell'elettricità è più alto. I lavori presentati dimostrano come lo stoccaggio non sia sempre la soluzione energeticamente più vantaggiosa poiché questi necessita di cariche preventive e successive scariche che vanno ad influire sui consumi. Tuttavia, lo stoccaggio permette di allontanare i consumi dai periodi di on-peak e quando presenti delle strategie di DSM, viene confermato come lo stoccaggio sia di aiuto nella riduzione dei costi. Nei lavori viene dimostrato come un contesto Cinese di tariffazione elettrica possa rendere lo stoccaggio un'applicazione di successo, questo poiché i prezzi durante l'off-peak sono sensibilmente più bassi dei prezzi della fascia on-peak. Inoltre, si dimostra come misure semplici di DSM siano solitamente sufficienti a migliorare l'efficienza energetica, questo è dovuto al fatto che il settore edilizio non ha bisogno di grandi stravolgimenti qualora siano impiegate tariffe variabili su scala oraria e soprattutto energie rinnovabili.Demand side management (DSM) consists in a set of practices and activities designed to affect the amount or timing of customers’ energy demand in order to use electricity more efficiently. DSM decreases the cost of meeting the customers' increasing energy demand by means of an investment in end-use energy efficiency and load management. As a result, this allows for an increased flexibility in the power generating systems and thus improving the energy supply balance in the network and reshaping the electricity market. DSM brings along a variety of advantages including the decrease of CO2 emissions and a development of a more efficient use of energy. Furthermore, DSM also allows for greater stability in the electricity prices for all market players. The load management is one of DSM objectives, this means changing the customers’ load profiles in a more efficient way. Among the broad variety of load shape profile combinations, Load Shifting and Peak Clipping are the most widely used demand patterns. This is mainly attributed to the fact that they are relatively quick and easy to perform without the requirement for a significantly advanced technology. Both demand patterns have been particularly researched in the presented works. Interesting opportunities come from the use of DSM strategies for the management of electric devices. A very promising combination is when the heat pumps operate according to DSM strategies, more precisely when load management is applied. Such a DSM strategy can be implemented by means of additional equipment that enables load shaping, among all, thermal energy storage (TES) is a valid tool. In DSM program, a TES can be used for electric load management in buildings by shifting electrical heating and cooling demands e.g. from peak periods to off peak periods. The application of TES in DSM can thus add flexibility to the energy management as shown in the various works considered in this study’s literature review. With respect to previous studies, the novelty of this work lies in the application of DSM real existing cases within the building sector which also integrate renewable energy sources into the system. Initially, reliable experimental data from realistic experimental campaigns was consulted. Subsequently, simulation models were built in order to closely represent the true behavior recorded in each of the studied experimental campaigns. The purpose of such simulation models was to study the integration of DSM strategies in the built environment and to analyze the effect of the thermal loads on the electricity consumption as well as the building energy performances in the long run. Results from this work confirm how DSM strategies can positively impact on the buildings’ and systems’ performances as they help increasing energy efficiency and system flexibility. Moreover, the application of DSM has proven to reduce the energy consumption of the presented cases and the electricity bills, particularly when dynamic electricity tariffs are implemented. The DSM measures turn out to be economically feasible when integrated with TES system which allows for the electric consumption demand to be shifted to time of cheaper electricity prices. This research study also illustrates how a TES system is not necessarily always the best solution in terms of energy consumption as it requires an initial charging and subsequent discharging, thus requesting energy to the whole system. However, such a measure helps smoothen out the overall electricity consumption patterns as it reduces the peak period electricity demand as it offsets such a demand to the off-peak period when cheaper tariffs are in operation. This research study demonstrates how a Chinese tariffs context can be successful for the TES application as the off-peak electricity tariff is considerable lower than the on peak tariff. Simple DSM measures are often enough to significantly improve energy efficiency. Furthermore, the building sector does not necessitate an extreme overturning if renewable energy or dynamic taxation are implemented.
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ROMAGNOLI, ALESSANDRA. "Efficientamento energetico degli edifici: metodologie ed analisi dei componenti edilizi Energy retrofit: methodologies and analyses of building components." Doctoral thesis, Università Politecnica delle Marche, 2018. http://hdl.handle.net/11566/252560.
Повний текст джерелаАнотація:
L’oggetto iniziale del progetto di ricerca era la valutazione del comportamento energetico di un quartiere composto da due edifici a stecca per un totale di 219 alloggi. Il complesso, di proprietà del Comune di Ancona, si trova in forte stato di degrado con notevoli problematiche inerenti i consumi energetici, il comfort interno e la salubrità degli ambienti. La ricerca si prefiggeva lo scopo di analizzare nuove strategie per l’ottimizzazione dell’involucro edilizio e del sistema edificio-impianto con lo scopo di ridurre la domanda di energia per il riscaldamento e il raffreddamento degli edifici, sulla base della direttiva sull'efficienza energetica (EED-2012/27/UE) che ha istituito un quadro comune di misure per la promozione dell'efficienza energetica nell'Unione, al fine di garantire gli obiettivi del "pacchetto climaenergia 20/20/20". Durante i tre anni di ricerca gli studi hanno mostrato come la valutazione e le analisi di edifici così complessi non porti a risultati totalmente soddisfacenti, perché le variabili in gioco sono elevate e, nonostante i monitoraggi in situ delle condizioni climatiche sia interne che esterne, è difficile valutare le interconnessioni di causa – effetto tra i dati monitorati e il comportamento dell’edificio stesso. Per cui, mentre si sono proseguite con le simulazioni, per cercare di risolvere i problemi tangibili di efficientamento energetico e riqualificazione, si è cercato di dare soluzione a vari aspetti puntuali inerenti le simulazioni, il risparmio energetico e possibili strategie di retrofit.
Le problematiche affrontate sono principalmente tre:
l’inerzia termica e la sua relazione con il comfort interno;
la simulazione dei ponti termici in regime semi-stazionario e dinamico;
l’influenza delle serre solari come sistemi di riscaldamento passivo.The object of this research project is the energy characterization of an urban district composed by two buildings for a total of 219 apartments. The complex, owned by the Ancona municipality, faces acute degradation and significant issues in terms of energy consumption, indoor comfort and healthiness. The main purpose is to analyze new strategies for the optimization of the building envelope and the technical systems to reduce the heating and cooling demand, based on the relevant energy directive (EED-2012/27 / UE) which provides a common framework of measures to promote the energy efficiency throughout the Union and progress towards the European 20-20-20 Targets. Over the three years of research, it has been ascertained that the assessment and the analysis of such buildings, even supported by monitoring campaigns, do not lead to any satisfactory results, given the number of variables at stake and the difficulty to strike causal links between on-site collected data and the building response. Consequently, along with simulation-based activities, specific solutions have been developed in the frame of potential retrofit strategies, energy efficient measures and modelling issues. Overall, three main topics have been addressed: thermal inertia and the way it impinges on indoor comfort; simulation of thermal bridges in semi steady state and dynamic regime; role of sunspaces as passive heating systems.
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Psimopoulos, Emmanouil. "Smart control of PV and exhaust air heat pump systems in single-family buildings." Licentiate thesis, Uppsala University, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:du-32581.
Повний текст джерелаАнотація:
Recently, decentralized household photovoltaic (PV) systems have become more affordable and there is a tendency to decrease subsidies for the PV excess electricity fed into the grid. Therefore, there is growing interest in methods to increase the self-consumption (SC), which is the part of the electricity produced by PV and directly consumed on buildings. It has been found that battery storage is an effective way to achieve this. When there is a heat pump system installed, thermal energy storage using the thermal mass of the building or hot water tanks, can also be used to increase the household self-sufficiency and minimize the final energy use. The main aim of this thesis is to develop operational control strategies for the heating system of a single-family house with an exhaust air heat pump, a photovoltaic system and energy storage. In order to accomplish this a detailed system model was developed in TRNSYS 17, which includes a six-zone building model and the heat pump control. Moreover, these control strategies include short-term weather and price forecast services. Another objective is to evaluate the impact on the benefit of these control strategies in terms of energy use and economic performance for a wide range of boundary conditions (country/climate, electricity prices, occupancy and appliance loads). Results show that the control using a forecast of dynamic electricity price in most locations leads to greater final energy savings than those due to the control using thermal storage for excess PV production. The exception is Sweden, where the result is the opposite. Moreover, the addition of battery storage leads to greater decreases in final energy than the use of the thermal storage (TH mode), which is limited to the thermal mass of the building and small hot water tank of the compact heat pump. As far as the impact of the advanced control (combined use of TH and PRICE) on cost savings is concerned, savings (up to 175 €) are possible in Spain and in Germany. The design of the TH and PRICE mode show low computational complexity that can be easily implemented in existing heat pump controllers. Additionally, the PRICE mode should have no capital and running cost for the end user while the TH mode might require an external electricity meter. Another yet implication with the TH mode is the need to activate the room thermostatic valve.
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Abolghasemi, Moghaddam Saman. "The effects of low-emissivity window films on thermal comfort and energy performance of a historic stone building in cold climate: computer simulations with "IDA ICE"." Thesis, Högskolan i Gävle, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-30145.
Повний текст джерелаАнотація:
Low-emissivity (low-E) window films are designed to improve the energy performance of windows and prevent indoor overheating by solar radiation. These films can be applied to different types of glazing units without the need for changing the whole window. This characteristic offers the possibility to improve the energy performance of the window of old and historic buildings for which preservation regulations say windows should remain more or less unchanged. This research aims to figure out to what extent a low-E window film can improve thermal comfort and energy performance of an old three-storey historic stone building in the cold climate of Mid-Sweden. In this research, first, with help of the simulation software “IDA ICE”, the entire building was modelled without window films in a one-year simulation. Second step was to add the low-E window films (3M Thinsulate Climate Control 75 (CC75)) to all the windows and repeat the simulation. Comparison between the results of the two cases revealed an improvement in energy use reduction as well as the thermal comfort when applying the films. For the application of the window films, a cost analysis using payback method was carried out which showed a long- time payback period. Although an investment with a long-time payback period is considered as a disadvantage, for historic buildings with very strict retrofit regulations specially when it comes to the building’s facades, application of the low-emissivity window films for better energy performance and thermal comfort is among the recommendable measures, but not necessarily the best.
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Hassanie, Samer. "A Systematic Approach to Integrated Building Performance Assessment and Visualisation." Licentiate thesis, KTH, Installations- och energisystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192563.
Повний текст джерелаАнотація:
The aim of this project was to develop a holistic approach to building-performance assessment without limiting it to energy use (usually expressed in kWh/m2/year), but rather include more parameters that represent the following aspects: Economic, environmental, and quality of service provided to the occupant/client. If it can be shown that buildings can be operated not only in an energy-efficient way, but also in a way that takes into consideration the needs of the occupants, a case could be built that a higher quality of indoor environment does not necessarily mean a higher economic impact. It is also important to show that having access to high-quality building-performance data leads to high-quality analysis and visualisation, and consequently to a chance to detect faults and improve building operation. To answer these questions, a large office building in Stockholm, Sweden was used as a case study. The building was equipped with energy meters and 1,700 sensor points, uniformly distributed over the occupied areas, that measured room temperature, duct temperature, occupancy presence/absence and supply airflow, in addition to other states. The data was processed using RStudio, and various types of visualisation plots were used, including carpet plots, masked scatter plots, bar plots, line graphs, and boxplots. The data pointed to some interesting results. First, just knowing the energy use is not sufficient for understanding the quality of the service provided to the occupants. Second, performing a thorough analysis of room unit data can detect faults. Third, using carpet plots for energy-data visualisation is effective for energy-use pattern recognition. Finally, visualising the building performance parameters in a parallel coordinate plot is a more informative representation of integrated building performance compared to the energy performance certificates typically used today.QC 20160916
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Duran, Ozlem. "Evaluation of retrofitting strategies for post-war office buildings." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/32268.
Повний текст джерелаАнотація:
The energy used in non-domestic buildings accounts for 18 % of the energy use in the UK. Within the non-domestic building stock, 11 % of office buildings have a very high influence on the energy use. Thus, the retrofit of office buildings has a significant potential for energy efficiency and greenhouse gas emissions reduction within the non-domestic building stock. However, the replacement rate of existing buildings by new-build is only around 1-3 % per annum. Post-war office buildings, (built between 1945 and 1985) represent a promising sector for retrofit and energy demand reduction. They have disproportionately high energy consumption because many were built before the building regulations addressed thermal performance. The aim of the research is to evaluate the retrofit strategies for post-war office buildings accounting for the improved energy efficiency, thermal comfort and hence, productivity, capital and the running costs. The research seeks to provide the optimal generic retrofit strategies and illustrate sophisticated methods which will be the basis for guidelines about post-war office building retrofit. For this, multiple combinations of heating and cooling retrofit measures were applied to representative models (Exemplar) of post-war office buildings using dynamic thermal simulation modelling. The retrofit strategies include; applying envelope retrofit to UK Building Regulations Part L2B and The Passivhaus Institue EnerPHit standards for heating demand reduction and winter comfort. Passive cooling interventions such as shading devices and night ventilation and active cooling intervention such as mixed-mode ventilation were applied to overcome summer overheating. All retrofit combinations were evaluated considering future climate, inner and outer city locations and different orientations. In summary, the results showed that under current weather conditions Part L2B standard retrofit with passive cooling provided the optimum solution. In 2050, however, both Part L2B retrofit naturally ventilated cases with the passive cooling measures and EnerPHit retrofit mixed-mode ventilation cases provide the requisite thermal comfort and result in a similar range of energy consumption. It was concluded that to create generic retrofit solutions which could be applied to a given typology within the building stock is possible. The methodology and the Exemplar model could be used in future projects by decision-makers and the findings and analysis of the simulations could be taken as guidance for the widespread retrofit of post-war office buildings.
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Al-Hadban, Yehya. "Demand-side management in office buildings in Kuwait through an ice-storage assisted HVAC system with model predictive control." Thesis, Cranfield University, 2005. http://hdl.handle.net/1826/3885.
Повний текст джерелаАнотація:
Examining methods for controlling the electricity demand in Kuwait was the main
objective and motivation of this researchp roject. The extensiveu se of air-conditioning
for indoor cooling in office and large commercial buildings in Kuwait and the Gulf
States represents a major part of the power and electricity consumption in such
countries. The rising electricity generation cost and growing rates of consumption
continuously demand the construction new power plants. Devising and enforcing
Demand-SideM anagemen(t DSM) in the form of energye fficient operations trategies
was the response of this research project to provide a means to rectify this situation
using the demand-side management technique known as demand levelling or load
shifting. State of the art demand-sidem anagementte chniquesh ave been examined
through the developmenot f a model basedp redictive control optimisations trategyf or
an integrateda ndm odulara pproachto the provisiono f ice thermals torage.
To evaluate the potential of ice-storage assisted air-conditioning systems in flattening
the demand curve at peak times during the summer months in Kuwait, a model of a
Heating, Ventilation, and Air-conditioning (HVAC) plant was developed in Matlab. The
model engaged the use of model based predictive control (MPQ as an optimisation tool
for the plant as a whole. The model with MPC was developed to chose and decide on
which control strategy to operate the integrated ice-storage HVAC plant. The model
succeeded in optimising the operation of the plant and introduced encouraging
improvement of the performance of the system as a whole.
The concept of the modular ice-storage system was introduced through a control zoning
strategy based on zonal orientation. It is believed that such strategy could lead to the
modularisation of ice-storage systems. Additionally, the model was examined and tested
in relation to load flattening and demonstrated promising enhancement in the shape of
the load curve and demonstrated flattened demand curves through the employed
strategy. When compared with measured data from existing buildings, the model
showed potential for the techniques utilised to improve the load factor for office
buildings.
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Bouraleh, Maryan. "Techno-economic Potential of Customer Flexibility : A Case Study." Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278079.
Повний текст джерелаАнотація:
District heating plays a major role in the Swedish energy system. It is deemed a renewable energy source and is the main provider for multi-family dwellings with 90 %. Although the district heating fuel mix consists of majority renewables, a share of 5 % is provided from fossil fuels. To reduce fossil fuel usage and eradicate CO2-emissions from the district heating system new solutions are sought after. In this project, the potential for shortterm thermal energy storage in buildings is investigated. This concept is referred to as customer flexibility. Demand flexibility is created in the district heating system (DHS) by varying the indoor temperature in 50 multi-family dwellings with maximum 1◦C, without jeopardizing the thermal comfort for the tenants. The flexible load makes it possible to store energy shortterm in the building’ envelope. Consequently, heat load curves are evened in production. This leads to a reduction of the peak load in the DHS. Peaks are associated with high costs and environmental impact. Therefore, the potential benefits of customer flexibility are reduced peak production, fuel costs, and CO2-emissions, depending on the fuel mix in the DHS. The project objective is to examine the techno-economic potential of customer flexibility in a specific DHS. The case study is made in a DHS owned by the company Vattenfall, located in the Stockholm area. To evaluate the potential benefits of implementing the concept, seven key performance indicators are chosen. They are peak power, peak fuel usage, produced volume, total fuel cost, fuel cost per produced MWh, climate footprint, and primary energy. Moreover, an in-house optimization model is used to simulate multiple scenarios of the district heating DHS. Different sets of assumptions about the available flexibility in the DHS and the thermal characteristics of the buildings are made. Customer flexibility is modeled as virtual heat storage that can be charged up or down depending on the speed and size of the available storage at a specific outdoor temperature. Simulation results give a maximum peak power reduction of 10.9 % and annual fuel cost reduction between 0.9-3.6 % depending on the scenario. The results found are comparable to values found in similar studies. However, the environmental key performance indicators generated an increase in CO2-emissions and primary energy compared to the baseline scenarios. The result would have looked different if fossil fuels were used in peak production instead of biofuels. The master thesis also aimed to validate assumptions and parameters made in the input data to the optimization model. This was achieved by using results attained from a pilot in the specific DHS. Therefore results generated from the simulations are deemed accurate and confirm that customer flexibility leads to reduced peak production and DHS optimization.Se filen
31
Oehme, Sabina. "Demand flexibility potential from heat pumps in multi-family residential buildings." Thesis, Uppsala universitet, Fasta tillståndets fysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-355135.
Повний текст джерелаАнотація:
The Swedish energy power system is in the middle of a paradigm shift where the increased share of intermittent energy sources place higher demand on the ability to regulate and balance the generation and consumption of electricity. Demand flexibility, which means that consumers can adjust their energy consumption, is a promising solution to manage the imbalance in the power system. Electric heat pumps in residential buildings are recognized to have potential to serve as a flexible load. In this thesis, an aggregated multi-family residential building model is developed to generate heat load profiles for a larger number of buildings which facilitate an assessment of the heat pump flexibility. The flexibility assessment is performed for a local distribution grid area with 174 buildings and an electricity price region in Sweden with 10 146 buildings with heat pumps. The flexibility assessment analyses the heat pump load deviation between a base load case and a case where the heat pumps receive an off-signal. The assessment takes into consideration seven flexibility parameters and is conducted for ambient temperatures between -20°C and 15°C. The thermal inertia of multi-family residential buildings facilitates a load shift with a duration of 4.4 to 9.8 hours depending on the ambient temperature. The maximal average power reduction for one hour of 10 MW in a distribution grid and 169 MW in an electricity price region illustrates the potential of using heat pumps as a demand flexibility solution in the electricity grid.
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Yaser, Hussnain A. "Novel System Design For Residential Heating And Cooling Load Shift Using PCM Filled Plate Heat Exchanger And Auxiliaries For Economic Benefit And Demand Side Management." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397234246.
Повний текст джерела
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Kamal, Rajeev. "Optimization and Performance Study of Select Heating Ventilation and Air Conditioning Technologies for Commercial Buildings." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6656.
Повний текст джерелаАнотація:
Buildings contribute a significant part to the electricity demand profile and peak demand for the electrical utilities. The addition of renewable energy generation adds additional variability and uncertainty to the power system. Demand side management in the buildings can help improve the demand profile for the utilities by shifting some of the demand from peak to off-peak times.
Heating, ventilation and air-conditioning contribute around 45% to the overall demand of a building. This research studies two strategies for reducing the peak as well as shifting some demand from peak to off-peak periods in commercial buildings:
1. Use of gas heat pumps in place of electric heat pumps, and
2. Shifting demand for air conditioning from peak to off-peak by thermal energy storage in chilled water and ice.
The first part of this study evaluates the field performance of gas engine-driven heat pumps (GEHP) tested in a commercial building in Florida. Four GEHP units of 8 Tons of Refrigeration (TR) capacity each providing air-conditioning to seven thermal zones in a commercial building, were instrumented for measuring their performance. The operation of these GEHPs was recorded for ten months, analyzed and compared with prior results reported in the literature. The instantaneous COPunit of these systems varied from 0.1 to 1.4 during typical summer week operation. The COP was low because the gas engines for the heat pumps were being used for loads that were much lower than design capacity which resulted in much lower efficiencies than expected.
The performance of equivalent electric heat pump was simulated from a building energy model developed to mimic the measured building loads. An economic comparison of GEHPs and conventional electrical heat pumps was done based on the measured and simulated results. The average performance of the GEHP units was estimated to lie between those of EER-9.2 and EER-11.8 systems. The performance of GEHP systems suffers due to lower efficiency at part load operation. The study highlighted the need for optimum system sizing for GEHP/HVAC systems to meet the building load to obtain better performance in buildings.
The second part of this study focusses on using chilled water or ice as thermal energy storage for shifting the air conditioning load from peak to off-peak in a commercial building. Thermal energy storage can play a very important role in providing demand-side management for diversifying the utility demand from buildings. Model of a large commercial office building is developed with thermal storage for cooling for peak power shifting. Three variations of the model were developed and analyzed for their performance with 1) ice storage, 2) chilled water storage with mixed storage tank and 3) chilled water storage with stratified tank, using EnergyPlus 8.5 software developed by the US Department of Energy. Operation strategy with tactical control to incorporate peak power schedule was developed using energy management system (EMS). The modeled HVAC system was optimized for minimum cost with the optimal storage capacity and chiller size using JEPlus.
Based on the simulation, an optimal storage capacity of 40-45 GJ was estimated for the large office building model along with 40% smaller chiller capacity resulting in higher chiller part-load performance. Additionally, the auxiliary system like pump and condenser were also optimized to smaller capacities and thus resulting in less power demand during operation. The overall annual saving potential was found in the range of 7-10% for cooling electricity use resulting in 10-17% reduction in costs to the consumer. A possible annual peak shifting of 25-78% was found from the simulation results after comparing with the reference models. Adopting TES in commercial buildings and achieving 25% peak shifting could result in a reduction in peak summer demand of 1398 MW in Tampa.
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Gastaldello, Danilo Sinkiti. "Desenvolvimento de metodologia para previsão da demanda de energia elétrica residencial considerando aspectos socioeconômicos e ferramentas computacionais inteligentes." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-04082017-151342/.
Повний текст джерелаАнотація:
O aumento da demanda por energia registrado nos últimos anos preocupa, pois a construção de novas fontes geradoras é barrada, muitas vezes, por restrições ambientais. Assim, o governo e as empresas de energias estão investindo em um melhor planejamento do sistema. No entanto, para haver uma proposta mais consistente para os consumidores residenciais se faz necessário conhecer melhor o perfil de cada consumidor, que é uma tarefa um tanto quanto difícil, visto que cada consumidor possui o livre arbítrio para consumir a energia de acordo com o conforto que ele deseja, de acordo com seus padrões econômicos e conforme aspectos culturais e sociais do ambiente em que ele vive. Neste contexto, a proposta desta tese foi analisar os impactos que os aspectos socioeconômicos tinham sobre o consumo de energia da classe residencial, sendo desenvolvido um algoritmo que gera curvas de carga virtuais baseadas em dados estatísticos do IBGE e da ANEEL. A partir dados de curvas virtuais, as ferramentas computacionais inteligentes, mais especificamente, as Redes Bayesianas e a Floresta de Caminhos Ótimos, foram treinadas com intuito de avaliar a possibilidade de criação de perfis e classificação dos consumidores e de suas características. Os resultados alcançados demonstram que a consideração dos aspectos socioeconômicos em avaliação de curvas de carga são pertinentes e que devem fazer parte do planejamento do sistema. Outra constatação é que as ferramentas computacionais inteligentes estudadas podem ser exploradas para auxiliar na previsão de consumo e criação de padrões e perfis dos consumidores.The need for energy has increased in the past years, thus requiring the design of new power plants. However, the project of such new constructions has been considerably neglected, mainly due to environment constraints. However, the whole government and companies are now focusing on a better management of the national energy grid. Despite that new policy, there is a need for a better knowledge concerning the user\'s behavior in order to present proposals that really take into account the consumers, since each them has the freedom to use the energy the way he wants to, as well as according to his socioeconomic habits. In this context, this thesis proposes to analyze the socioeconomic impacts of the energy consumption concerning residential consumers, being also developed an algorithm that generates virtual load curves based on statistical data from both IBGE and ANEEL. With that data on hand, the intelligent tools, e.g., Bayesian Networks and Optimum-Path Forest, were trained aiming at evaluating the possibility to create profiles for the further identification of their classes according to that information. The results obtained highlighted the importance of the socioeconomic information when evaluating the load curves, which should be part of the whole system. Another conclusion concerns the intelligent tools, which can be further used for consumer forecasting, as well as to create patterns related to the consumers\' profiles.
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Ko, Hsin-Ting. "Techno-economic analysis of demand flexibility from heat pumps for multi-family buildings in Sweden based on two case studies." Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-272472.
Повний текст джерелаАнотація:
Sweden is undergoing energy transition to become a zero-carbon economy with electricity production aims at 100% from renewable resources by 2040. Sweden also has a national goal to have fossil-free vehicle fleet by 2030. The increasing share of intermittent renewable resources creates growth in mismatches between electricity supply and demand. Demand flexibility provides solution to imbalances in power system where the prosumers can regulate their energy consumption. Demand response (DR) mechanism could be beneficial to power gird stability. Electric heat pumps serve as a pool of flexible load meanwhile the thermal inertia of the residential buildings serves as thermal energy storage. In this thesis, a techno-economic analysis of demand flexibility from heat pumps for residential buildings located in central Örebro is carried out with assistance of building energy simulations. This thesis aims to improve the intelligence of this existing buildings by comprehending the size of thermal inertia availability according to different heat demand, building envelope materials, ventilation systems, weather conditions and user behaviors. Two multi-family residential buildings, Klockarängsvägen and Pärllöken, are selected for case study and compared in terms of thermal inertia and avoided peak power fees in avoided peak power fee from flexible heat pump loads. Both buildings use heat pumps for space heating and domestic hot water supply. Electricity billings are subscribed to power tariff scheme, which makes peak power shifting more profitable. On the coldest day scenario when the ambient temperature is -20°C, Pärllöken’s indoor temperature drops from 21°C to 19.1°C if heat pump is turned off for an hour. Klockarängsvägen’s indoor temperature drops from 21°C to 16.6°C if heat pump is turned off for an hour. At the lowest indoor temperature setpoint of 18°C, Pärllöken demonstrates a maximum power-shift capacity of 25 kW and heatshift capacity of 75 kWh on the coldest day. That of Klockarängsvägen is a maximum power-shift capacity of 20 kW and heat-shift capacity of 20 kWh. With larger building thermal inertia and more power-shift capacity, Pärllöken is undoubtedly the winner thanks to concrete wall materials, heavier building thermal mass, balanced ventilation, heat recovery system, and higher window class. In economic analysis, based on the proposed energy models, two control strategy options in Pärllöken are considered. Economic analysis focuses on winter season from October to March. Option 1 operates heat pump in variable capacity control mode at part load capacity. Option 2 operates in fixed capacity on/off -4- control. In winter season, Pärllöken saves 1 646 SEK in Option 1 and 2 273 SEK in Option 2. Klockarängsvägen only considers Option 1 for economic analysis, which results in 20 948 SEK avoided peak power fee. Option 2 for Klockarängsvägen exceeds indoor temperature setpoint very quickly mainly due to poorer building envelope insulation in which conserves lower thermal inertia.Sverige genomgår en energitransformation för att bli en fossilfri ekonomi som siktar på att ha en elproduktion från 100% förnybara resurser år 2040. Sverige har också ett nationellt mål att ha en fossilfri fordonsflotta till 2030. Den ökande andelen av intermittenta förnybara resurser bidrar till ökning av obalans mellan produktion och efterfråga av elektricitet. Efterfrågeflexibilitet ger en lösning på problemet med obalanser i energisystemet där prosumenter kan reglera sin energiförbrukning. Efterfrågeflexibilitet kan vara fördelaktigt för kraft- och nätstabilitet. Elektriska värmepumpar kan agera som en stor flexibel last samtidigt som fastighetens termiska tröghet fungerar som värmeenergilagring. I denna avhandling utförs en teknisk-ekonomisk analys av efterfrågeflexibilitet från värmepumpar för två bostadshus beläget i centrala Örebro med hjälp av energisimuleringar av fastigheten. Genom denna avhandling syftar författaren på att höja intelligensen av de befintliga fastigheterna genom att undersöka storleken av den termiska trögheten som finns tillgänglig med avseende på olika värmescenario, byggnadsmaterial, ventilationssystem, väderförhållanden och användarbeteenden. Två flerfamiljshus, Klockarängsvägen och Pärllöken, väljs för jämförelse med avseende på den termisk tröghet som bidrar mest till efterfrågeflexibiliteten. De två utvalda fastigheterna använder värmepumpar för värme och varmvatten. Båda fastigheterna faktureras enligt effektabonnemang, vilket gör effektutjämning mer lönsamt. I det kallaste scenariot, när omgivningstemperaturen är -20°C, faller Pärllökens inomhustemperatur från 21°C till 19,1°C och Klockarängsvägens inomhustemperatur sjunker till 16,6°C om värmetillförseln stängs av i en timme. Under det lägsta börvärdet för inomhustemperatur på 18°C visar Pärllöken en maximal effektförskjutningskapacitet på 25 kW och för Klockarängsvägen-byggnader 20 kW. Med hänsyn till fastighetens termiska tröghet är Pärllöken utan tvekan vinnaren på grund av betong som väggsmaterial, högre termisk massa, balanserad ventilation, värmeåtervinningssystem och högre energiklass på fönsterglasen. Ovanstående skäl gör att Pärllökens termiska tidskonstant är minst tre gånger längre innan temperaturen når det lägsta börvärdet på 18°C, jämfört med Klockarängsvägen. Detta ger att Pärllöken har en högre förskjutningskapacitet av värme på 75 kWh jämfört med Klockarängsvägens maximala förskjutningskapacitet på 20 kWh. I en ekonomisk analys, baserat på författarens framtagna energimodeller, beaktas två styrstrategier i Pärllöken. Den ekonomiska analysen fokuserar på vintersäsongen från oktober till mars. Alternativ 1 driver värmepumpen med partiell kapacitet enligt reglerbar effekt. Alternativ 2 stänger av värmepumpen helt. Under vintersäsongen sparar Pärllöken 1 646 SEK med Alternativ 1 och 2 273 SEK med Alternativ 2. Klockarängsvägen använder sig endast av Alternativ 1 för en ekonomisk analys, vilket resulterar i en kostnadsbesparing på 20 948 SEK. En förstudie med värmepump i kombination med andra förnybara tekniker så som solceller på Klockarängsvägen genomförs för att undersöka potentialen av energibesparing. Kombinationen ger dock inte en positiv effekt på grund av den låga solinstrålningen under vintertid.
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Liu, Lei. "Investment planning under daily operation: A sustainable housing community context." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/123736/2/Lei_Liu_Thesis.pdf.
Повний текст джерелаАнотація:
This research develops a systematical tool to recommend the best short-term operation and long-term investment planning to manage energy bills for neighbourhoods and precincts. Building energy efficiency measures, rooftop solar systems and batteries are evaluated with detailed operational simulation to estimate yearly bill savings across the economic lifetime of investment options. The outcome of this work is that integrated operation and investment options can provide the best return on energy investment for community cases.
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Ritz, Carolina, and Malin Mattsson-Mårn. "Utformningens betydelse för energiförbrukningen : En fallstudie av verksamhetsbyggnader." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Byggnadsteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-28281.
Повний текст джерелаАнотація:
Purpose: The building sector accounts for 40 % of the total energy consumption in Sweden today, and the largest proportion is consumed during the operating phase. From the year 2020 and onwards, all new buildings should be erected as zero-emissionbuildings. The building’s design can reduce energy demands, but the current legal requirements do not favour energy-efficient designs. This study focuses on the design’s importance for the energy efficiency of buildings, i.e., energy-saving design. The impact of specific measures is difficult to calculate due to the complexity of reality. This study aims to highlight the measures that could reduce energy consumption in commercial buildings. Method: In order to provide answers to the issues stated in the report and to achieve the objective of the study, case studies are being conducted investigating three commercial buildings where deliberate decisions were made to use energy-reducing measures. Results and conclusions are based on qualitative interviews and literature studies. Findings: The energy-reducing design measures found to be of most importance used in the studied buildings are the form factor, the window portion and the thermal storage capacity. Moreover, significant savings are possible by carefully consider how solar energy can be limited or used in the building. Generally, buildings tends to become more technical, therefore technical knowledge early in the process is important to reach a good result. Economic incentives and clear objectives with right focus are also important for optimizing a building’s energy performance. The wording and the requirement levels in the Swedish building regulations highly controls the construction of energy efficient buildings. Implications: This study shows how energy efficient design is made today and provides an indication of what can be done and what should be prioritized. By imposing requirements on consumed energy instead of bought, energy efficient design could be favoured. Furthermore, this study suggests that a balance between windows, façade and solar shading are important energy-reducing measures. Regardless of selected energyreducing measures, a good performance is essential. Finally, this study shows that a methodical use of existing knowledge and technology makes a difference. Limitations: A lifecycle approach provides an overall picture of a building’s energy consumption. However, this study is based on the energy consumption during the operating phase. The result of this study does not take economic or aesthetic factors into account. This study is a comparative case study and is based on few but carefully matched cases. The selected cases are commercial buildings where deliberate decisions were made to use energy-reducing measures.
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Irffi, Guilherme Diniz. "PrevisÃo da demanda de energia elÃtrica para o nordeste utilizando OLS dinÃmico e mudanÃa de regime." Universidade Federal do CearÃ, 2007. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1405.
Повний текст джерелаАнотація:
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoEsse estudo se propÃe estimar a demanda por energia elÃtrica para as classes residencial, comercial e industrial na regiÃo Nordeste do Brasil, no perÃodo de 1970 a 2003. Utilizando as metodologias desenvolvidas por Stock e Watson (1993) e Gregory e Hansen (1996), respectivamente, DOLS e MudanÃa de Regime para obter as elasticidades-preÃo e renda de longo prazo. A partir dos vetores de cointegraÃÃo sÃo estimados os Modelos de CorreÃÃes de Erros, os quais fornecem a base para se fazer previsÃes de longo prazo, no perÃodo de 2004 a 2010. A partir dos resultados apresentados por este estudo, sÃo feitas comparaÃÃes das elasticidades-preÃo e renda de curto e longo prazo com demais estudos para o Brasil, bem como para as previsÃes feitas pela EletrobrÃs e por Siqueira, Cordeiro Jr. e Castelar (2006). As metodologias utilizadas nesse estudo, apresentam previsÃes mais acuradas do que os demais estudos para os anos de 2004 a 2006.
The objective of this research is to estimate the residential, commercial and industrial demand for electric energy in the Northeast region of Brazil during the period of 1970 2003. Two different methodologies were used to compute the price and income elasticity of demand: i) DOLS, proposed by Stock and Watson (1993); and ii) Regime Switching by Gregory and Hansen (1996). Error Correction Models are estimated from the cointegration vectors. These models are used to perform long-run forecasts of the electricity demand for the period 2004- 2010. The results are then compared to those from other researches about Brazilianâs price and income elasticity of demand for electric energy. Furthermore, the computed forecasts are compared to those from EletrobrÃs and from Siqueira, Cordeiro Jr. e Castelar (2006). The methodologies used in this work present forecasts that are more accurate than those ones from nother works for the period 2004-2006.
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Strengers, Yolande Amy-Adeline, and Yolande strengers@rmit edu au. "Bridging the divide between resource management and everyday life: smart metering, comfort and cleanliness." RMIT University. Global Studies, Social Science and Planning, 2010. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20100329.165839.
Повний текст джерелаАнотація:
Smart metering residential demand management programs, such as consumption feedback, variable pricing regimes and the remote control of appliances, are being used to respond to the resource management problems of peak electricity demand, climate change and water shortages. Like other demand management programs, these strategies fail to account for (and respond to) the reasons why people consume resources in their homes, namely to carry out everyday practices such as bathing, laundering, heating and cooling. In particular, comfort and cleanliness practices together constitute most of Australia's potable water consumption in urban centres, and represent most of household energy consumption. In addition, new household cooling practices involving air-conditioning appliances are the major contributor to the nation's rising peak electricity demand, which overloads the electricity system on hot days, costing consumers millions of dollars each year. The oversight of comf ort and cleanliness practices in smart metering demand management programs is concerning because these practices are continuing to shift and change, often in more resource-consuming directions, potentially negating the resource savings achieved through demand management programs. This thesis aims to bridge the problematic divide between the policies and strategies of demand managers, and the day-to-day practices which constitute everyday life. Using the empirical 'hook' of smart metering demand management programs and the everyday practices of comfort and cleanliness, this thesis develops a practice-based conceptual framework to study, understand and analyse these practices and the ways in which smart metering demand management programs reconfigure or further entrench them. A series of qualitative methods were employed in studying 65 households across four research groups, focusing specifically on the household practices of heating, cooling, bathing, laundering, toilet flushing and house cleaning. In addition, 27 interviews were conducted with smart metering industry stakeholders involved or implicated in delivering demand management strategies. Together, these lines of inquiry are used to analyse householders' existing and changing comfort and cleanliness practices, the role of several smart metering demand management strategies in reconfiguring these practices, and potential avenues and opportunities for further practice change in less resource-intensive directions. In particular, this thesis highlights the inherent contradictions and problems in accounting for everyday practices within the dominant demand management paradigm, and offers an alternative paradigm termed the co-management of everyday practices. The thesis concludes by briefly identifying the ways in which smart metering could potentially constrain or catalyse a transition towards this new paradigm.
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Höglund, Marcus, and Anton Stenås. "Komfort- och energianalys vid installation av markiser på Högskolans i Gävle glasfasader : Mätningar och IDA ICE-simuleringar." Thesis, Högskolan i Gävle, Energisystem och byggnadsteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-36108.
Повний текст джерелаАнотація:
Högskolan i Gävle planerar att installera solavskärmande markiser på entréhallarnas sydliga glasade fasader. Sedan uppbyggnad har entrébyggnaden som inkluderar ”Rävhallen” och ”Fårhallen” lidit av bristfällig termisk inomhuskomfort på grund av värmeläckage och överhettning orsakade av fasadernas fönsterpartier. Detta examensarbete gjordes i syfte att via mätningar undersöka den termiska inomhuskomforten i Högskolans i Gävle entréhallar. Arbetet syftade också till att årssimulera och analysera årlig energiförbrukning och termisk inomhuskomfort innan och efter installationen av solavskärmande markiser på byggnadens glasfasader, i simuleringsprogrammet IDA ICE. En komfortundersökning gjordes genom att mäta termisk komfort och inomhustemperaruter under två tillfällen i april månad. Mätningarna gjordes under en molnig dag och en solig dag vid samma utomhustemperatur, för att undersöka solinstrålningens inverkan på byggnadens termiska komfort och inomhustemperaturer. Komfortundersökningen visade att den termiska komforten i Rävhallen och Fårhallen var undermålig då överhettning uppstår vid hög solinstrålning. Nödvändiga data inför modellering och simulering insamlades genom observationer, uppskattning, beräkningar och samtal med drifttekniker vid Akademiska hus. Efter datainsamlingen konstruerades en modell i simuleringsprogrammet IDA ICE. Innan simulering validerades modellen med hjälp av tidigare uppmätta temperaturer under april månad. Sedan simulerades byggnadens energiförbrukning och termiska inomhuskomfort över ett helt år, utan markiser, och därefter med markiser. Resultatet visade att den termiska komforten förbättrades markant vid installation av markiser. Höga topptemperaturer som tidigare förekom i byggnaden minskade eftersom markiserna reducerade solinstrålningen genom fasadens fönsterpartier. Det totala årliga energibehovet ökade dock från 605 MWh till 635 MWh. Det årliga energibehovet för kyla minskade något från 3,4 MWh till 3,2 MWh. Att energiförbrukningen ökade berodde på att markiserna reducerade nyttig gratisvärme från solinstrålningen, särskilt under uppvärmningssäsong. För vidare forskning föreslås en mer effektiv styrteknik av markiserna och en mer detaljrik simuleringsmodell för att få tillförlitligare resultat. Vid tillämpning av bättre anpassad styrning av markiserna bedöms energibesparingspotentialen bli större. Slutsatsen drogs att markiser kan förbättra den termiska inomhuskomforten avsevärt, men att energiförbrukningen kan komma att öka beroende på styrteknik.The University of Gävle plans to install solar shading awnings on the southern glass facades of the main entrances. Since construction, the main entrances Rävhallen and Fårhallen have suffered from poor thermal indoor comfort due to heat leakage and overheating due to the windows on the facades. This thesis was done in order to map and investigate the thermal indoor comfort in the University of Gävle's main entrances. The work also aimed to simulate and analyze annual energy consumption and thermal indoor comfort before and after the installation of solar shading awnings on the building's glass facades, in the simulation program IDA ICE. A comfort survey was conducted by measuring thermal comfort and indoor temperature ranges on two occasions in April. The measurements were made during a cloudy day and a sunny day at the same outdoor temperature, to investigate the effect of solar radiation on the building's thermal comfort and indoor temperatures. The comfort survey showed that the thermal comfort in Rävhallen and Fårhallen was insufficient as overheating occurs at high solar radiation. Data necessary for modeling and simulation was collected through observations, estimates, and dialogs with operating technicians from Akademiska hus. After data collection, a model was constructed in the simulation program IDA ICE. Before simulation, the model was validated using previously measured temperatures during the month of April. Then the building's energy consumption and thermal indoor comfort were simulated over a whole year, without awnings, and with awnings. The results showed that the thermal comfort was significantly improved by the awnings installations. High peak temperatures that previously occurred in the building decreased because of the reduced solar radiation through the glass facade. The total annual energy demand increased from 605 MWh to 635 MWh. However, the annual energy demand for cooling decreased from 3,4 MWh to 3,2 MWh. The increase in energy consumption was due to the awnings reducing useful heat from solar radiation, especially during the heating season. Prior to further research, a more efficient control technique of the awnings and a more detailed model to improve the simulation results are proposed. When applying better adapted control of the awnings, the energy saving potential is considered to be greater. It was concluded that awnings can significantly improve indoor thermal comfort, but that energy consumption may increase depending on control technology.
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Santo, Luca. "AA-CAES physical modelling: integration of a 1D TES code and plant performance analysis." Thesis, Uppsala universitet, Tillämpad kärnfysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-360448.
Повний текст джерелаАнотація:
The focus of this thesis work was the development of an approachto couple a previosly existing Thermal Energy Storage (TES) modelwritten in C++ with a Simulink/Simscape plant model to simulate anAdvanced Adiabatic Compressed Air Energy Storage (AA-CAES) plant.After the creation and validation of such tool, the complete modelwas used to run simulations, with the aim of assessing the AA-CAESplant's performance under multiple patterns of charge anddischarge.Most of the works found in the literature only provide values ofstorage efficiency obtained from analytical approaches, whilethose that use simulation tools provide average values ofefficiencies when the plant is performing a series of identicalcycles of charge and discharge. During this thesis project,instead, simulations were performed for consecutive irregularcycles determined as the plant response to the electric grid powerrequest. The average efficiency values obtained provide thereforea better representation of how the plant would perform in realapplications.The results show that, under the assumptions made, the AA-CAESplant's overall storage efficiency is influenced very weakly byalterations of the charge-discharge patterns, and that goodperformances can be expected not only for identical chargedischargeconsucutive cycles, but for any pattern that observesthe cavern pressure limits, as long as the thermal energy storageis sized wisely.In addition, a sensitivity analysis was performed in order toassess the influence of turbomachinery efficiency on overallstorage efficiency, for a specified plant layout. The results showthat the turbine efficiency is the most affecting parameter to theplant's performance, while the impact of the main compressors'sinefficiency is mitigated by the thermal recovery that takes placein the TES.The present work confirms that AA-CAES is a promising technologyand that storage efficiencies above 70% can be achieved even inrealistic production scenarios.Finally, future steps for more accurate simulations of plants'performances and more detailed energy production scenarios areproposed.MSc ET 18007Examinator: Joakim WidénÄmnesgranskare: Ane HåkanssonHandledare:
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Pospíšil, David. "Zvýšení tepelně-izolačních parametrů klasických obytných budov a jejich vliv na kvalitu vnitřního prostředí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229922.
Повний текст джерелаАнотація:
Master’s Thesis deals with utilization of energy simulation software in area of classic brick buildings and measures to decrease heat consumption. Introduction deals with historic development of heat loss demands in Czech Republic and ways how to decrease heat loss through different types of building elements. Next chapter is focused on indoor microclimate and it’s affecting factors. Last but not least are mentioned environmental and financial aspects of these adjustments. Final part shows examined buildings, simulation configurations and output evaluations.
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Faramarzi, Ghazal, and Malin Torestam. "Development of evaluation tools as an approach to pre-design district energy systems : Qualitative modeling and performance simulation using OpenModelica." Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-288104.
Повний текст джерелаАнотація:
Cities and districts contribute to a large fraction of the total energy consumption in Sweden. The residential- and service sector accounted for almost 40% of the total energy consumption in 2018. The increasing urbanization also puts more importance on the energy supply, distribution and consumption in these areas. One way of planning an energy system in urban areas is to have integrated energy systems where synergies between different technologies and energy carriers are utilized. Such a solution can increase the flexibility of the energy system and thus help integrate more intermittent renewable energy sources. The aim of this study was to suggest tools for planning energy systems in districts. This was done by performing a literature review regarding the design of energy systems and the identification of barriers and opportunities for the integration of different production- and distribution technologies. The focus was on systems for heating, cooling and electricity. The proposed tools are three Excel-based modules. The first module is a qualitative model that presents the reviewed technologies and their connections. It also includes synergies between different energy carriers and sectors for consumption and production. The second module is qualitative model related to market mechanisms, juridical, organizational and institutional aspects. The third module is a table containing the barriers and opportunities. Furthermore, relevant stakeholders are identified to be district heating companies, building owners, joint associations, municipalities, district cooling companies and photovoltaic plant owners. The proposed tools can be used in the first stage of planning when the technologies are selected. To show how the suggested tools can be applied, a case study was performed. The study case is a district being planned in Stockholm, Sweden. For the analysis, a model for a hypothetical heating system was required. Two models were developed for the heat supply system using the modelling environment OpenModelica. The main objective of the case study was to compare the techno-economic and environmental performance of different scenarios. Three different scenarios were considered for covering the total heating demand in the district. In the first scenario the total heating demand is covered only by local heat pumps. In the second scenario the space heating demand is covered by heat pump(s) coupled with a thermal energy storage (hot water tank). An electric boiler is used as backup. In the third scenario, the electric boiler is replaced by district heating as backup. A sensitivity analysis was included for different numbers of heat pumps and different sizes of thermal energy storage in the two last scenarios. The economic and environmental results in this study were strongly dependent on the assumptions regarding prices and emission factors. The result of the case study indicates that the third scenario causes the lowest CO2 emissions. An increased size of the thermal energy storage causes a higher compressor electricity consumption thus more emissions. However the total emissions from the system depends on the backup component. For this result, the emission factor related to Swedish electricity mix and the emission factor stated by a district heating company in Stockholm was used. The cheapest alternative in terms of annual operational cost of energy is the first scenario with only heat pumps. However, from the scenarios which also includes thermal energy storage, the second scenario with three heat pumps and a 100 m3 large thermal energy storage, presents the lowest cost. This system design in scenario 2 is only 0.6% more expensive than the first scenario. For the energy prices, the assumption for electricity is based on hourly values from Nordpol and for heat, the values presented in a normal price list from a district heating company is assumed. Regarding the technical performance of the system the result indicates that the contribution from the thermal energy storage as it is modelled in this case study is not significant on anannual basis. However it is observed that a larger thermal energy storage unit covers a higher fraction of the power demand during the hours it is utilized.Städer och stadsdelar står för en stor del av totala energikonsumtionen i Sverige. Bostads- och servicesektor stod för ungefär 40% av totala energikonsumtionen under 2018. Den ökande urbaniseringen lägger också mer vikt vid energiproduktion, distribution och konsumtionen i dessa områden. Ett alternativ för planering av energisystem i urbana områden är att ha integrerade energisystem där synergier mellan olika teknologier och energibärare kan utnyttjas. Den typen av system skulle kunna öka flexibiliteten i energisystemet och därför förenkla integrering av oförutsägbara förnybara energikällor. Syftet med denna studie var att föreslå verktyg för planering av energisystem i stadsdelar. Detta gjordes genom en litteraturstudie angående utformningen av olika energisystem samt identifiera hinder och möjligheter för att integrera olika produktions- och distributions teknologier. Fokus låg på systemen för värme, kyla och elektricitet. Det föreslagna verktygen är tre Excel baserade moduler. Den första modulen är en qualitative modell som presenterar de studerade teknologier och deras kopplingar. Den innehåller också synergier mellan de olika energibärarna och konsumtions- och produktionssektorn. Den andra modulen är en qualitative modell, men relaterad till marknad mekanismer, juridiska, organisatoriska och institutionella aspekter. Den tredje modulen är en tabell som beskriver hinder och möjligheter för några av teknologierna. Utöver det de relevanta aktörerna identifierades. För värme-, kyla- och elektricitet marknaden är de fjärrvärmeföretagen, fastighetsägare, samfälligheter, kommuner, fjärrkyla företagen, solcells ägare. De föreslagna verktyget kan användas för planering av energisystem i ett första skede när teknologier ska väljas. En fallstudie genomfördes för att visa hur det föreslagna verktyget kan användas. Fallstudien en stadsdel som planeras i Stockholm, Sverige. För att genomföra en analys behövdes en modell för ett hypotetiskt värmesystem. Två modeller utvecklades för värmesystemet genom att använda modelleringsmiljön OpenModelica. Det huvudsakliga målet med fallstudien var att jämföra den teknoekonomiska- och miljöinriktade prestandan för olika scenarierna. Tre olika scenarier övervägdes för att täcka totala värmebehovet i stadsdelen. I det första scenariot täcks det totala värmebehovet endast av lokala värmepumpar. I andra scenariot täcks värmebehovet för uppvärmning av värmepump(ar) kopplade till en värmelagrings komponent (ackumulatortank). En elpanna användes för reserveffekt. I tredje scenariot är elpannan ersatt av fjärrvärme. En känslighetsanalys var utförd för olika antal värmepumpar kopplade till olika storlekar av värmelagrings-komponenten i de två sista scenarierna. De ekonomiska och miljörelaterade resultatet i den här studien är starkt beroende av antaganden gällande priser och utsläppsfaktorer. Resultatet indikerar att det tredje scenariot har de lägsta CO2 utsläppen. Ökad värmelagringsstorlek bidrar till att värmepumpen förbrukar mer elektricitet och därför ökar de relaterade utsläppen. Däremot beror de totala utsläppen i systemet på vilken reservkraft som används. För dessa resultat användes utsläppsfaktorn för svensk elmix samt utsläppsfaktorn från ett fjärrvärme företag i Stockholm. Den billigaste alternativet gällande årlig driftsenergikostnad är det första scenariot med endast värmepumpar. Däremot, bland de scenarion som innehåller värmelagring, har det andra scenariot med tre värmepumpar och 100m3 stor värmelagringsenhet den lägsta kostnaden. Detta system är endast 0.6% dyrare än det första scenariot. För energipriser har timvärden från Nordpol antagits för elektricitet och för värme har normalprislistan från ett fjärrvärmebolag i Stockholm antagits. Angående den tekniska systemprestandan, indikerar resultatet att bidraget från värmelagringsenheten som den är modellerad i den här fallstudien inte är signifikant på årsbasis. Det observeras emellertid att en större värmelagringsenhet täcker en större andel av effektbehovet under de timmar som enheten används.
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Larmérus, Alexander. "Styrning av värmesystem i kontorsbyggnader : Jämförelse mellan prognosstyrning, styrning som utnyttjar byggnadens värmetröghet, samt traditionell styrning." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146975.
Повний текст джерелаАнотація:
En stor del av Sveriges energianvändning går till bostäder och lokaler. Ur en nationell synvinkel är energieffektiviseringar i befintliga byggnader därför en potentiellt viktig del för att kunna nå de satta klimatmålen till år 2020. I ett traditionellt styr- och reglersystem styrs framledningstemperaturen i ett vätskeburet värmesystem efter en kurva som beror på utomhustemperaturen. En del nya styr- och reglersystem tar även hänsyn till andra parametrar, såsom byggnaders värmetröghet och lokala väderprognoser. Ett exempel på ett sådant system är Ecopilot, utvecklat av Kabona. Nuvarande kunskap angående hur stor energibesparing som styr- och reglersystem med prognosstyrning och styrning som utnyttjar byggnadens värmetröghet ger upphov till består till största del av referensfall som jämför byggnaders energianvändning före och efter installationen. I detta examensarbete undersöktes hur energianvändning och inomhusklimat påverkades av prognosstyrning och styrning som utnyttjar byggnaders värmetröghet. Mätningar utfördes på två kontorsbyggnader vid namn Fräsaren 10 och Fräsaren 11. Båda byggnaderna är belägna i Sundbyberg och har Kabona Ecopilot installerat. Mätdata loggades genom redan utsatta givare och en enklare form av validering av dessa gjordes. I Fräsaren 10 och Fräsaren 11 jämfördes Ecopilot i normal drift med driftfallet då prognosstyrningsfunktionen stängdes av i Ecopilot. Även ett tredje driftfall undersöktes i Fräsaren 10. Under detta driftfall stängdes Ecopilot av och framledningstemperaturen styrdes med hjälp av reglerkurvor. I luftbehandlingsaggregaten sattes tilluftstemperaturens börvärde, till 19-20 °C. Varje driftfall hade en mätperiod på minst 14 dagar. Energisignaturer användes för att jämföra energianvändningen och en osäkerhetsanalys av de anpassade linjerna gjordes. En egen modell för att undersöka toppbelastningar i radiatorsystemet, VS1, i Fräsaren 10 togs fram. Även en modell för att undersöka hur temperaturen varierat inomhus mellan de olika mätperioderna togs fram. Energisignaturer för radiatorsystemen VS1 och VS2 i Fräsaren 10 visade på att likvärdiga energisignaturer kunde fås för samtliga av de undersökta driftfallen under det temperaturintervall som undersöktes. Energisignaturer för värmeanvändning i luftbehandlingsaggregatet, LB2601, visade på att en konstant tillufttemperatur på 19 °C som användes då Ecopilot var avstängd, kunde ge en högre värmeanvändning jämfört med fallen då Ecopilot var i normal drift och då Ecopilot hade sin prognosstyrning avstängd. Från jämförelse mellan fallen då Ecopilot var i normal drift och då Ecopilots prognosstyrning var avstängd kunde inga substantiella skillnader hittas mellan energisignaturerna. Det betyder dock inte att prognosstyrningen inte ger upphov till energibesparingar, utan att eventuella energibesparingarna var för små relativt mätningarnas osäkerhet vid en konfidensnivå på 65 % eller 95 %. Osäkerheten kan minskas om mätningar utförs över en längre tidsperiod än som var möjligt under detta examensarbete. Värmetoppbelastningar som undersöktes i radiatorsystemet i VS1 Fräsaren 10 visade inte på att några signifikanta skillnader mellan antalet uppmätta värmeeffekttoppar under de olika mätperioderna. Det förekom dock en viss indikation att det kan leda till fler värmeeffekttoppar om prognosstyrningen stängs av i Ecopilot. För att få ett mer tillförlitligt resultat behöver mätningar göras under en längre tidsperiod. Inomhustemperaturen undersöktes i Fräsaren 10 och Fräsaren 11. I Fräsaren 10 uppgick medeltemperatur till 21,5 °C för fallen då Ecopilot var i normal drift och då prognosstyrningen var avstängd. Då Ecopilot var avstängd var medeltemperaturen 22,1 °C. Under mätperioderna uppmättes en variation som understeg ± 1 °C från medelvärdet för respektive mätperiod. Baserat på resultaten presenterade i detta examensarbete antaganden angående hur stor besparing av värme som Ecopilot ger upphov till revideras. Att jämföra energianvändning före och efter installation av styrsystem såsom Ecopilot kan ge en dålig bild av hur stor del av energibesparingen som orsakats av Ecopilot, speciellt om reglerkurvorna i det gamla systemet var dåligt intrimmade.
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Barbosa, Renato Mariano. "Contribuição dos créditos de carbono na viabilidade de projetos de eficiência energética térmica e de troca de combustíveis em cervejarias." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-13092011-161409/.
Повний текст джерелаАнотація:
Atualmente é de complexa equalização o problema advindo da elevação da demanda energética e das ações antrópicas que corroboram para o aquecimento global e, neste sentido, apesar de o Brasil ser abundante em hidroeletricidade, há ainda um grande espaço para o uso de outras fontes renováveis de energia, como a biomassa residual. Na indústria, projetos de adoção de novos e eficientes processos para a redução da carga térmica, bem como o uso de biomassa e de biogás das estações de tratamentos de efluentes podem ser um diferencial no conjunto de soluções para o dilema energético-ambiental, uma vez vão ao encontro dos objetivos das políticas energéticas globais em vigência, as quais pregam a segurança e sustentabilidade. Porém, verifica-se que tais medidas ainda têm sido desprezadas por muitas empresas, pois os investimentos são ainda muito elevados, ressaltando-se ainda que, talvez por não se entender como esses projetos podem internalizar as externalidades positivas que os acompanham, essas empresas seguem alheias aos benefícios socioambientais e econômicos advindos dos créditos de carbono, que podem compensar os altos investimentos realizados em racionalização energética. Desta maneira, essa dissertação analisa a viabilidade econômica da implantação de projetos de substituição de combustíveis fósseis por biomassa renovável para geração de vapor de processos; de uso de biogás de ETEs para geração de eletricidade e de implementação de tecnologias para a redução do consumo de vapor industrial, com foco em cervejarias, considerando-se nas análises econômico-financeiras os créditos de carbono recebidos pelas reduções de emissões de gases de efeito estufa. Pelas análises de cenários, verificou-se que quando as medidas de eficiência energética reduzirem pelo menos 5% da demanda energética, com um custo de energia de pelo menos R$ 187,50/MWh, bem como reduções de consumo de energia acima de 10%, com custo energético mínimo de R$ 122,50/MWh, e preço de das RCE acima de 5,00, os projetos mencionados são viáveis, e as receitas dos créditos podem internalizar as externalidades positivas desses projetos, compensando os investimentos.Nowadays it´s quite complex to solve the problem between energy demand growth and the human activities, which have negative, widespread effects on the global climate. In this sense, apart from the fact that Brazil adopts massivelythe hydropower, there is a large potential for the use of renewable energy sources, as biomass. In process industries, techologies for reducing thermal energy consumption associated with the use of the sustainable biomass and biogas from wastewater treatment systems can be one among other solutions for equalizing the energy-environment dilemma, also targeting the prorrogatives of the current global policies on safety and sustainable energy sypply. Anyway, such measures have still been left aside by many industries, because it´s still not properly understood regarding the way these projects can internilize their positive externalities, some enterprises keep distant from the social, economic and environmental beneffits that carbon credit projects can bring up to help them in succeeding and rationalizing energy consumption. This dissertation evaluates and assesses the economic viablitity of projects of fuel switch (from fossil fuels to renewable biomass); use of biogas from industrial wastewater treatment systems and also the implementation of technologies and processes for reducing steam comsumption, focusing on breweries. By means of economic sceneries, it´s shown that the revenues from carbon credits can significantly have positive impacts, while financial incentives, on the decision making process towards the carrying and dissemination of such projects. As demonstrated in this work, the RCE, if required in the sceneries analysed, can bring the cash flows whithin brewery IRR expectations. Hence, the model showed that when measures of energy afficiency achieve at least 5,0% with the price of energy saved is of at least R$187,50/MWh, and for measures above 10% and energy is bought at prices higher then R$ 122,50/MWh, all projects with CER prices above 5,00 viable, and can be conducted. Also, the revenues from carbon credits can make industries wake up for the fact that they can internalize the positive externalities of these projects, once the high investiments can be compensated by their carbon offsets.
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Šot, Petr. "Ověření tepelně-izolační vlastnosti termoreflexních fóliových izolací." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226729.
Повний текст джерелаАнотація:
The master´s thesis deals with verification of thermal insulating property of thermoreflection foil insulations. The teoretical part of thesis focuses on the energy demand of buildings, the problems of heat transfer material, terms required for study of thermoreflection thermal insulation and experimental methods for determination of thermal insulating properties of insulators. In the next part the chapter is accompanied by an overview of the most common insulation materials which used in construction. The last part of teoretical part is devoted to the description of thermoreflect formation and analysis of the spread of thermal insulating layers of thermoreflection thermal insulation. The first part of thesis is devoted to the use of thermoreflection therm insulation in buildings. The second part of thesis is devoted to the design, assembly and calibration of the measuring device that uses a method of protected warm chamber. It is declared as a binding method of detection of the heat transfer performance of thermoreflection thermal insulation. The developed measuring device allows detection of endpoints in some direction of propagation of heat. Measurment of heat transfer coefficient devoted the third part of practical part. This part contains a description of the samples used for the measurement of the heat transfer coefficient. In the fourth chapter of the practical part are presented the results of the heat transfer coefficient measurments on selected samples of thermoreflection foil insulation. It is shown the characteristic of heat transfer coefficient of individual samples, the dependence of the heat transfer coefficient on the position of the sample in the measuring device and the recommendation of an appropriate use of sample in the works for the climatic conditions of the Czech republic. The work concludes the chapter of comparing and evaluating of all samples with practical recommendations.
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Dabdoubi, Saida. "La maîtrise de la demande énergétique dans le secteur du bâtiment au Maroc : quels enjeux économiques et environnementaux." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCC021.
Повний текст джерелаАнотація:
Au Maroc, le secteur de l’énergie se caractérise par la faiblesse des ressources nationales en énergies fossiles et une forte dépendance des approvisionnements énergétiques du reste du monde. Parallèlement, la demande en énergie primaire connait ces deux dernières décennies une forte expansion qui devrait se prolonger dans le futur. Du coup, la maîtrise de la demande énergétique (MDE), à travers la mise en place du programme national de l’efficacité énergétique (PNEE) et son déploiement dans tous les secteurs économiques, constitue l’un des axes prioritaires de sa politique énergétique. Dans le secteur bâtiment, le PNEE porte sur la mise en place des instruments de politique publique visant à inciter les usagers à investir dans les solutions d’efficacité énergétique (EE) et dans les énergies renouvelables (EnR) et adopter un comportement de sobriété et de lutte contre le gaspillage.L’objectif de cette thèse est de procéder à l’évaluation de l’efficacité des instruments de la politique de MDE dans le secteur bâtiment. La démarche adoptée consiste à combiner les deux dimensions de l’évaluation ex-post de l’action publique : 1) la dimension normative pour apprécier l’efficacité des mesures mises en oeuvre ; 2) la dimension instrumentale qui vise à comprendre les résultats obtenus et à identifier les pistes d’amélioration. Il est question, en fait, de voir si les dispositifs d’ordre réglementaire et incitatif en application au Maroc permettent-ils de contourner toutes les barrières à l’investissement dans des actions de la MDE dans ce secteur. Il s’avère qu’il existe un déficit d’adoption des solutions d’EE et des EnR de la part des usagers et que les différents instruments mis en oeuvre ne peuvent suffire à le réduire. D’abord, certaines barrières ne sont pas levées car aucun outil approprié n’existe. Ensuite, certains facteurs de blocages ne sont que partiellement traités car l’utilisation pratique des outils diffèrent de leur conception théorique. Enfin, la politique de la MDE se trouve la plus part des temps contrariée par d’autres politiques publiques en matière de logement ou par l’incapacité des pouvoirs publics à mobiliser les différents intervenants dans l’acte de bâtir.Ce travail de recherche essaye de répondre à un certain nombre d’interrogations : la mise en place d’une politique de MDE est-elle justifiée au Maroc sachant que la consommation énergétique par habitant est très faible par rapport à la moyenne mondiale ? En quoi cette politique consiste-t-elle ? En quoi est-elle bénéfique pour le pays et pour les citoyens ? Quels sont les instruments économiques mis en oeuvre par les pouvoirs publics en vue d’inciter les usagers à maîtriser leur consommation énergétique et donc à atteindre les objectifs de réduction de la demande en énergie fixés ? Après plusieurs années de mise en oeuvre, quel bilan peut-on dresser au regard de ces objectifs ? Quelle évaluation d’impacts économique, social et environnemental peut-on faire ? Et quels sont les freins qui limitent l’action publique pour réduire la consommation énergétique dans le secteur bâtiment ?L’élaboration d’un programme de rénovation thermique massive des bâtiments publics est de nature à contribuer à l’atteinte des objectifs fixés par les pouvoirs publics en matière de maîtrise de la demande énergétique et de réduction des émissions de gaz à effet de serre. De par son importance et les effets d'entraînements positifs qu'il peut induire, le parc bâti des collectivités publiques représente un enjeu énergétique considérable. Il mérite, par3conséquent, de faire l'objet d'actions profondes en faveur de l'économie d'énergie. Le développement de ce programme répond également au devoir d’exemplarité dont les pouvoirs publics doivent faire preuveIn Morocco, the energy sector is characterized by the weakness of national resources in fossil fuels and a strong dependence on energy supplies from the rest of the world. At the same time, demand for primary energy has grown rapidly in the last two decades and is expected to continue in the future. As a result, controlling energy demand, through the implementation of the national energy efficiency program and its deployment in all economic sectors, is one of the priority areas of its energy policy. In the building sector (residential and tertiary), this program focuses on the implementation of public policy instruments aimed at encouraging users to invest in energy efficiency and renewable energy solutions and adopt a sober and fight against waste. The aim of this thesis is to assess the effectiveness of energy demand management policy instruments in the building sector. The approach adopted is to combine the two dimensions of the ex-post evaluation of public action: 1) the normative dimension to assess the effectiveness of the measures implemented; 2) the instrumental dimension, which aims to understand the results obtained and to identify areas for improvement.The question is, in fact, to see if the regulatory and incentive mechanisms applied in Morocco allow to circumvent all the barriers to investment in the actions of the control of the energy demand in the building sector. It turns out that there is a lack of adoption of energy efficiency solutions and renewable energy from users and that the various instruments implemented can not be enough to reduce it. First, some barriers are not lifted because no appropriate tool exists (the case of the thermal renovation of existing buildings). Then, some blocking factors are only partially addressed because the practical use of the tools differs from their theoretical design. Finally, the energy control policy is most of the time thwarted and neutralized by other public housing policies or the inability of public authorities to mobilize the various stakeholders in the act of building.This research work attempts to answer a number of questions: Is the implementation of a policy to control energy demand in Morocco justified given that per capita energy consumption is very low compared to the world average? What does this policy consist of? How does it benefit the country and its citizens? What are the economic instruments used by the public authorities to encourage users to control their energy consumption and thus to achieve the targets for reducing demand? After several years of implementation, what is the assessment of these objectives? What impact evaluation of these economic instruments can be done? Moreover, what are the barriers that limit public action to reduce energy consumption in the building sector?The development of a massive thermal renovation program for public buildings is likely to contribute to achieving the objectives set by the authorities in terms of controlling energy demand and reducing greenhouse gas emissions. Because of its importance and the effects of5positive training that it can induce, the public built park represents a considerable energy stake. It deserves, therefore, to be the object of deep actions in favor of saving energy. The development of this program also responds to the duty of exemplarity that the public authorities must demonstrate
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Hammarström, Anton. "Utvärdering av potential för värmeåtervinning från laborationsutrustning : Möjligheten att använda en kylvattenbassäng som termiskt säsongslager." Thesis, Mittuniversitetet, Avdelningen för kemiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-34309.
Повний текст джерелаАнотація:
HETA utbildningar i Härnösand har ett ångkraftverk för undervisningssyfte som kyls ner med vatten från en underjordisk bassäng på cirka 329 m³. Syftet med detta examensarbete har varit att undersöka hur bassängen med spillvärmen från kraftverket kan användas som ett säsongslager i kombination med en befintlig 7,8 kW värmepump för att värma upp maskinhallen i deras laboratoriebyggnad. Ett kalkylark skapades i Microsoft Excel för att kunna genomföra beräkningarna. Då mätdata saknades skapades ett simulerat scenario baserat på temperaturstatistik och körschema för kraftverket från år 2017. Transmissionsförluster beräknades för bassängen och maskinhallen. För bassängen användes mestadels observationsdata och kännedom hos personalen, medan maskinhallens isolering i huvudsak fick uppskattas efter byggår. Resultatet blev att värmepumpen med aktuellt körschema kunde täcka cirka 45 % av maskinhallens årliga uppvärmningsbehov. Av de 276 GJ som tillfördes genom kylning av ångkraftverket under ett år beräknades endast 2,7 % kunna utnyttjas till uppvärmning av maskinhallen, på grund av för lite isolering i bassängen. De största begränsningarna för högre täckning och större nyttjande av spillvärmen bedömdes vara placeringen i tid av kraftverkets körningar, och värmepumpens effekt. Om körningarna skulle förläggas i huvudsak till november–april och värmepumpen ersättas med en på 10 kW, skulle 74 % av värmebehovet kunna täckas och över 18 % av spillvärmen utnyttjas. Andra saker som förbättrad isolering i bassängen och större vattenvolym bedömdes också kunna förbättra bassängens kapacitet som energilager.HETA Education in Härnösand has a steam power plant for educational purposes which is cooled with water from a 329 m³ underground basin. The purpose of this thesis has been to examine how the basin with the waste heat can be used as seasonal thermal energy storage with an existing 7.8 kW heat pump in order to heat the machine room of their lab building. A spreadsheet was created in Microsoft Excel in order to carry out the calculations. As no measurement data was available, a simulated scenario was created based on temperature statistics and the operating schedule for the power plant from the year 2017. Transmission losses were calculated for the basin and the machine room. For the basin, mostly observational data and knowledge among the staff were used, while the insulation for the machine room mainly had to be estimated based on the construction year. The result was that the heat pump, with the current operating schedule, could cover around 45% of the yearly heating demand of the machine room. Of the 276 GJ that were added through cooling of the power plant during a year, according to calculations, only 2,7% could be used for heating the machine hall, due to lacking insulation in the basin. The greatest limitations for achieving a higher heating coverage and a greater usage of the waste heat were assessed to be the placement in time of the power plant runs, and the effect of the heat pump. If the runs would be placed mainly in November–April, and the heat pump replaced with a 10 kW one, around 74% of the heating demand could be covered and 18 % of the waste heat used. Other things, such as increased insulation in the basin and larger water volume were also assessed to be able to increase the capacity of the basin as heat storage.
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Saulich, Sven. "Generic design and investigation of solar cooling systems." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/13627.
Повний текст джерелаАнотація:
This thesis presents work on a holistic approach for improving the overall design of solar cooling systems driven by solar thermal collectors. Newly developed methods for thermodynamic optimization of hydraulics and control were used to redesign an existing pilot plant. Measurements taken from the newly developed system show an 81% increase of the Solar Cooling Efficiency (SCEth) factor compared to the original pilot system. In addition to the improvements in system design, new efficiency factors for benchmarking solar cooling systems are presented. The Solar Supply Efficiency (SSEth) factor provides a means of quantifying the quality of solar thermal charging systems relative to the usable heat to drive the sorption process. The product of the SSEth with the already established COPth of the chiller, leads to the SCEth factor which, for the first time, provides a clear and concise benchmarking method for the overall design of solar cooling systems. Furthermore, the definition of a coefficient of performance, including irreversibilities from energy conversion (COPcon), enables a direct comparison of compression and sorption chiller technology. This new performance metric is applicable to all low-temperature heat-supply machines for direct comparison of different types or technologies. The achieved findings of this work led to an optimized generic design for solar cooling systems, which was successfully transferred to the market.
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Yu, Kuan-Chieh, and 余冠頡. "Application of data mining technology in energy demand forecast." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/67w4t8.
Повний текст джерелаАнотація:
碩士國立勤益科技大學
工業工程與管理系
105
Energy is important for a country’s development. If there isn’t enough energy, all aspects of development will be subject to certain restrictions. The forecast of energy demand will be the indicators of the impact of decision-making. If the supply of energy is lower than the needs, there may be a power outage. On the other hand, it will lead to idle power, resulting in unnecessary waste of economic resources. In this study, using the K-means clustering algorithm and the Fuzzy C means clustering algorithm in the data mining to cluster the data in advance, in order to adjust the "effective lengths of intervals" in the Adaptive Neural-Network-Based Fuzzy Interference System(ANFIS) to improve the establishment of its fuzzy rule base. Based on Taiwan's population, Gross Domestic Product, total imports and export value from 1974 to 2015, this study uses K-means and Fuzzy C means with ANFIS to forecast the energy demand. In order to understand the accuracy of the model, this study is compared with other energy prediction studies, and the forecast is better than other’s. The results of this study, the RMSE and MAPE of the ANFIS with K-means were 1.548E +10 and 10.06%. The RMSE and MAPE of the ANFIS with Fuzzy C means were 1.553E + 10 and 10.36%. According to the results, clustering the data in advance can really solve the ANFIS fuzzy model "effective lengths of intervals" problem, and the accuracy has also increased. In addition, in the efficiency of model convergence, this study uses the data of the iterative situation to compare and finds that using the K-means with ANFIS would make the model more quickly into a stable state.