Dissertations / Theses on the topic 'Space Heating and Cooling'
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Terblanche, Johann Pierre. "Design and performance evaluation of a HYDROSOL space heating and cooling system." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97095.
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Thesis (MEng)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Space heating and cooling, as required for chicken poultry farming, is an energy intensive operation. Due to the continuous rise in the prices of fossil fuel, water and electricity, there is a need to develop renewable and sustainable energy systems that minimise the use of fuel or electricity, for heating, and water, for cooling of air. The HYDROSOL (HYDro ROck SOLar) system, developed at Stellenbosch University, is such a renewable energy system that potentially provides a low cost solution. Instead of using conventional gas and electricity heaters for the heating of air during winter, the HYDROSOL system collects solar heat, stores it in a packed bed of rocks and dispatches the heat as required. During hot summer days, when cooling is needed, the rocks are cooled during the night when the ambient temperatures are low and/ or by evaporative cooling by spraying water onto them. During the day, hot air is then cooled when it passes through the colder rocks with minimal water consumption compared to current systems. In this thesis, a prototype of the HYDROSOL system is presented, designed and built for experimental testing. A transient 2-D thermo flow model is developed and presented for the analytical and experimental performance evaluation of this system for solar heating and night air cooling operation. This model is used to conduct a parametric study on HYDROSOL to gain a better understanding of the operation and control of the system. The HYDROSOL concept is intended to be used for heating and cooling of residential buildings, office suites, warehouses, shopping centres, food processing industries e.g. drying of foods, and various agricultural industries e.g. greenhouses. In this thesis, a HYDROSOL system is developed mainly for poultry broiler houses in South Africa focussing on convective dry cooling, charging the rock bed with night-time ambient air, and convective heating, harvesting solar heat during the day, with different modes of operation available.
AFRIKAANSE OPSOMMING: Ruimte verhitting en verkoeling, soos benodig vir hoender pluimvee boerdery, is ‘n energie intensiewe bedryf. As gevolg van die voortdurende styging in fossiel brandstof-, water- en elektrisiteitpryse, het ‘n behoefte ontstaan om hernubare en volhoubare energie-stelsels te ontwikkel wat minder brandstof of elektrisiteit, vir verhitting, en water, vir verkoeling van lug, gebruik. Die HYDROSOL (HYDro ROck SOLar) stelsel, wat ontwikkel is by die Universiteit van Stellenbosch, is ‘n hernubare energie-stelsel wat ‘n potensiële lae koste oplossing bied. In plaas daarvan om konvensionele gas en elektrisiteit verwarmers vir verhitting van lug gedurende die winter te gebruik, maak HYDROSOL gebruik van son warmte, stoor dit in `n gepakte bed van klip en onttrek die warmte soos benodig. Gedurende die warm somer dae wanneer verkoeling benodig word, word die klippe gedurende die nag, met kouer omgewings lug en/of met verdampingsverkoeling, deur water op die klippe te spuit, afgekoel. Gedurende die dag word warm lug afgekoel deur die lug oor die koue klippe te forseer met minimale waterverbruik in vergelyking met huidige stelsels. ‘n Prototipe van die HYDROSOL word voorgestel, ontwerp en gebou vir eksperimentele doeleindes. ‘n 2-D tyd afhanklike termo- vloei model word voorgestel vir die analitiese en eksperimentele verrigting evaluering vir son verhitting en nag lug verkoeling. Hierdie model word gebruik om ‘n parametriese studie te doen om die werking en beheer van HYDROSOL beter te verstaan. Die HYDROSOL stelsel is bedoel om die verwarming en verkoeling vereistes van residensiële geboue, kantoor areas, pakhuise, winkelsentrums, voedsel verwerking nywerhede, soos bv. die droging van voedsel, en verskeie landboubedrywe, soos bv. kweekhuise, te bevredig. In hierdie tesis word ‘n HYDROSOL stelsel, hoofsaaklik vir pluimvee kuikenhuise in Suid- Afrika, ondersoek en fokus op die droë verkoeling, deur die rotsbed te laai gedurende die nag, asook droë- verhitting, wat gebruik maak van son energie gedurende die dag en kan beheer word op verskillende maniere.
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Navarro, Farré Lidia. "Thermal energy storage in buildings through phase change materials (PCM) incorporation for heating and cooling purposes." Doctoral thesis, Universitat de Lleida, 2016. http://hdl.handle.net/10803/398840.
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La reducció del consum energètic dels sistemes de calefacció i refrigeració dels edificis és un
repte fonamental per assolir els objectius marcats per l’Horitzó 2020. Noves aplicacions
d'emmagatzematge d'energia tèrmica en edificis es mostren prometedores per reduir aquest elevat
consum energètic. Un dels objectius d'aquesta tesi doctoral és revisar les aplicacions passives i
actives d'emmagatzematge d'energia que es troben en la literatura, especialment aquelles que
utilitzen materials de canvi de fase (PCM). En aplicacions passives els requeriments de confort i
les condicions climàtiques són els principals paràmetres que s’han tingut en compte fins ara. Per
això s'estudia la influència de càrregues internes en el aplicacions passives de PCM. D'altra
banda, es presenta un sistema innovador que actua com una unitat d'emmagatzematge tèrmic i
alhora com un sistema de calefacció i refrigeració. El rendiment tèrmic d'aquest sistema es testeja
sota condicions reals i s'avalua el seu potencial de reducció del consum d'energia.La reducción del consumo energético de calefacción y refrigeración de los edificios es un reto para lograr los objetivos marcados por el Horizonte 2020. Nuevas aplicaciones de almacenamiento de energía térmica en edificios se muestran prometedoras para reducir este elevado consumo energético. Uno de los objetivos de esta tesis doctoral es revisar aplicaciones pasivas y activas de almacenamiento de energía que se encuentran en la literatura, especialmente aquellas con materiales de cambio de fase (PCM). En aplicaciones pasivas los requerimientos de confort y las condiciones climáticas son los principales parámetros que se han tenido en cuenta hasta ahora. Se estudia la influencia de cargas internas en aplicaciones pasivas de PCM. También, se presenta un sistema innovador que actúa como una unidad de almacenamiento térmico y como calefacción y refrigeración. El rendimiento térmico de este sistema se testea bajo condiciones reales y evalúa su potencial de reducción del consumo energético.
Reducing the energy consumption of heating and cooling systems of buildings is a key challenge to achieve the targets set for the Horizon 2020. New applications of thermal energy storage in buildings are promising to reduce the high energy consumption. One of the objectives of this PhD is to review passive and active applications of thermal energy storage in buildings found in the literature, especially those that use phase change materials (PCM). In passive applications comfort requirements and climatic conditions are the main parameters that have been considered so far. For this study, the influence of internal loads has been taken into account in passive PCM applications. Moreover, an innovative system which acts as a storage unit and a heating and cooling supply is presented. The thermal performance of this system is studied and the potential in reducing the energy consumption of heating and cooling is evaluated.
3
Swann, Barbara. "Establishing design criteria for the incorporation of highly glazed spaces into the domestic building envelope." Thesis, Cranfield University, 1996. http://dspace.lib.cranfield.ac.uk/handle/1826/4033.
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This thesis investigates the design of domestic glazed spaces in the United Kingdom, by studying the effect of a range of variables on the thermal properties of glazed spaces, in order to achieve a thermally comfortable environment while minimising the use of energy for heating and cooling. Earlier research work on domestic glazed spaces has concentrated on optimising the design of the space as a mechanism for reducing the space heating load of the parent house. Computer based dynamic thermal simulation is used in this study as the method of assessment and the variables tested are; glazing type, orientation and the degree of integration of the glazed space with the parent building. Unshaded, unventilated, and unheated, glazed spaces were found to be thermally comfortable for only a quarter to a third of the hours of possible use whatever the form, orientation or glazing type. Generally the higher the insulating value of the glazing the fewer the number of comfortable hours for all orientations and arrangements, due to discomfort being caused by high temperatures, even though the weather data used for the simulations only rose above 27'C for 25 hours during the course of the year. Further studies showed that significant reductions in the number of hours experiencing high temperatures could be achieved by the use of buoyancy driven ventilation. The studies indicated that glazed spaces integrated into the house plan tended to experience high temperatures for long periods but that the peak temperatures were much lower than those experienced for shorter periods in the exposed spaces. The effect of ventilation on overheating was therefore more marked in the integral than in the exposed glazed spaces. A study of the effects of roof shading blinds indicated that internal blinds had minimal effect in reducing high temperatures. External blinds had a greater effect than ventilation and a combination of external roof blinds and ventilation appears to provide the best strategy for the control of high temperatures. Studies on space heating loads for the houses and glazed spaces indicated wide variations in the heating loads of the glazed spaces depending predominantly on the insulating properties of the glazing. In terms of the reduction in the space heating load for the parent house, the thermal simulation results predict very little change due to the presence of the glazed space. A study on the effect of increasing the thermal storage properties of the floor construction of the glazed spaces, by substituting a clay tile finish for the original thin carpet layer, in order to reduce high temperatures proved inconclusive with minimal changes in the number of comfortable hours experienced. An investigation of thermal comfort during the Winter indicated that low surface temperatures did not reduce resultant temperatures below the lower limit of the comfortable range in the glazed spaces, during the heated period.
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Du, Hu. "Modelling of building performance under the UK climate change projections and the prediction of future heating and cooling design loads in building spaces." Thesis, Northumbria University, 2012. http://nrl.northumbria.ac.uk/5837/.
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New climate change projections for the UK were published by the United Kingdom Climate Impacts Programme in 2009. They form the 5th and most comprehensive set of predictions of climate change developed for the UK to date. As one of main products of UK Climate Projections 2009 (UKCP09), the Weather Generator, can generate a set of daily and hourly future weather variables at different time periods (2020s to 2080s) and carbon emission scenarios (low, medium and high) on a 5 km grid scale. In a radical departure from previous methods, the 2009 Projections are statistical-probabilistic in nature. A tool has been developed in Matlab to generate future Test Reference Year (TRY) and Design Reference Years (DRY) weather files from these Projections and the results were verified against results from alternative tools produced by Manchester University and Exeter University as well as with CIBSE’s Future Weather Years (FWYs) which are based on earlier (4th generation) climate change scenarios and are currently used by practitioners. The Northumbria tool is computationally efficient and can extract a single Test Reference Year and 2 Design Reference Years from 3000 years of raw data in less than 6 minutes on a typical modern PC. It uses an established ISO method for generating Test Reference Year data and an alternative method of constructing future Design Reference Years data is proposed. Fifteen different buildings have been identified according to alternative usage, thermal insulation, user activity and construction details. Besides these variants, the buildings were chosen specifically because they either exist, or have received planning consent and so represent ‘real’ UK building examples. Two investigations were then carried out based on the 15 case study buildings. The first involved applying TRYs generated for London, Manchester and Edinburgh for a variety of carbon emission scenarios at time horizons of 2030, 2050 and 2080. The TRYs were developed into a weather data format readable by the EnergyPlus energy simulation program to simulate summertime internal comfort (operative) temperatures, cooling demands and winter heating demands. All results were compared with a control data set of nominally current weather data, together with the same results produced using the alternative weather data generators of Manchester University, Exeter University and the CIBSE FWYs. Results revealed a good agreement between the various methods and show that significant increases in internal summer operative temperatures in non-air-conditioned buildings can be expected as time advances through this century, as well as increased air conditioning cooling energy demands and small reductions in winter heating energy demand. The second investigation involved generating time series of design internal peak summertime operative temperatures, design cooling demands and design winter heating demands for the same conditions as the first investigation. The results were then used to develop a simplified estimation method to predict future design cooling loads using multiple regressions fitting to selected data from the DRY simulation inputs and outputs. The simplified estimation method forms a useful tool for estimating how future cooling design loads in buildings are likely to evolve over time. It also provides a basis for designers and practitioners to determine how buildings constructed today will need to be adapted through life to cope with climate change.
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McGilligan, Charles. "Securing a pathway which leads to an 80% reduction in greenhouse gas emissions : effects of climate change on levels of space heating and space cooling, and analysis of the energy saving potential of the adaptive approach to thermal comfort in the built environment." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577755.
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Climate change brings with it a set of challenges if our buildings are to remain thermally comfortable whilst energy consumption is kept to a minimum and greenhouse gas emissions are reduced. As a means of addressing these issues, three models have been constructed using future climate data as forecast by the UK Climate Projections (UKCP09), and they have been used to inform the Department of Energy and Climate Change (DECC) 2050 Calculator. Observing there to be a correlation between regionalised National Grid non-daily metered gas demand and daily air temperature, the first model uses these data and UKCP09 data to estimate future energy savings deriving from a reduced requirement for space heating across the built environment. Using UKCP09 data, the second model estimates the increase in the uptake of residential air-conditioning if the UK were to follow the same experience as Canada, regression data showing a correlation between penetration levels of air-conditioning in the residential sector and air temperature in North America. Resultant levels of space cooling energy consumption are calculated using two different bottom-up approaches, the first of which uses the dwelling as the base unit, and the second of which uses the air-conditioner. Deriving from conventional degree-day theory and substantiated through a series of building simulations, the third model uses a novel metric, the Adaptive Comfort Degree-Day, to estimate the energy savings potential of employing adaptive comfort standards for future climates using UKCP09 data. Finally, it is found that pathways prescribed as achieving an 80% reduction in emissions levels by 2050 remain successful when the DECC 2050 Calculator is updated with correctly-weighted air temperatures. However, the demand for space heating is under-estimated by up to 99 TWh when the Calculator is amended so as to take account of data from the preceding space heating model.
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Kirmizi, Hacer. "The Effect Of Sun Spaces On Temperature Patterns Within Buildings: Two Case Studies On The Metu Campus." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/2/12611427/index.pdf.
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The aim of this study was to investigate the passive and active parameters affecting
energy efficiency of two office buildings with sun spaces, namely the MATPUM
Building and the Solar Building on the Middle East Technical University (METU)
Campus, Ankara and the effect of sun spaces on temperature patterns within
mentioned buildings. Both buildings were oriented in the same direction, namely
south. However, the location and the type of the sunspaces differed from each other.
The sun space in the MATPUM Building is an atrium which has southerly glazed
façade. On the other hand, the sun space in the Solar Building is an enclosed conservatory which has southerly glazed faç
ades and roof. The effect of sun spaces on temperature patterns within case study buildings was determined by collecting internal temperature and humidity data from different locations within the buildings and external temperature and humidity data on certain days of the week from May to August and October and November. Data loggers were used to collect these data. The collected data was then compared for the two buildings and also for the different months. In conclusion, more heat gain resulting in temperature increase inside the buildings was obtained in conservatories when compared to the atria which have glazed faç
ade instead of glazed roof. This was also proved by the analysis of variance method which was used for the comparison of temperature data of two buildings
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Soderlund, Matthew Roger. "Congeneration dedicated to heating and cooling." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17672.
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Dong, Bing. "Integrated Building Heating, Cooling and Ventilation Control." Research Showcase @ CMU, 2010. http://repository.cmu.edu/dissertations/4.
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Current research studies show that building heating, cooling and ventilation energy consumption account for nearly 40% of the total building energy use in the U.S. The potential for saving energy through building control systems varies from 5% to 20% based on recent market surveys. In addition, building control affects environmental performances such as thermal, visual, air quality, etc., and occupancy such as working productivity and comfort. Building control has been proven to be important both in design and operation stages.
Building control design and operation need consistent and reliable static and dynamic information from multiple resources. Static information includes building geometry, construction and HVAC equipment. Dynamic information includes zone environmental performance, occupancy and outside weather information during operation.. At the same time, model-based predicted control can help to optimize energy use while maintaining indoor set-point temperature when occupied. Unfortunately, several issues in the current approach of building control design and operation impede achieving this goal. These issues include: a) dynamic information data such as real-time on-site weather (e.g., temperature, wind speed and solar radiation) and occupancy (number of occupants and occupancy duration in the space) are not readily available; b) a comprehensive building energy model is not fully integrated into advanced control for accuracy and robustness; c) real-time implementation of indoor air temperature control are rare. This dissertation aims to investigate and solve these issues based on an integrated building control approach.
This dissertation introduces and illustrates a method for integrated building heating, cooling and ventilation control to reduce energy consumption and maintain indoor temperature set-point, based on the prediction of occupant behavior patterns and weather conditions. Advanced machine learning methods including Adaptive Gaussian Process, Hidden Markov Model, Episode Discovery and Semi-Markov Model are modified and implemented into this dissertation. A nonlinear Model Predictive Control (NMPC) is designed and implemented in real-time based on Dynamic Programming. The experiment test-bed is setup in the Solar Decathlon House (2005), with over 100 sensor points measuring indoor environmental parameters such as temperature, relative humidity, CO2, lighting, motion and acoustics, and power consumption for electrical plugs, HVAC and lighting. The outdoor environmental parameters, such as temperature, relative humidity, CO2, global horizontal solar radiation and wind speed, are measured by the on-site weather station. The designed controller is implemented through LabVIEW.
The experiments are carried out for two continuous months in the heating season and for a week in cooling season. The results show that there is a 26% measured energy reduction in the heating season compared with the scheduled temperature set-points, and 17.8% energy reduction in the cooling season. Further simulation-based results show that with tighter building façade, the cooling energy reduction could reach 20%. Overall, the heating, cooling and ventilation energy reduction could reach nearly 50% based on this integrated control approach for the entire heating/cooling testing periods compared to the conventional scheduled temperature set-point.
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Bol, Bullen A. D. "A pervaporation membrane absorption cooling heating system." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289081.
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Poulis, P. D. A. "Radiant wall and floor heating and cooling." Thesis, Open University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384588.
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Karlström, Petra. "Soft Heating and Cooling in Humid Climates." Thesis, KTH, Byggnadsteknik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-35098.
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Chekh, O. "Heat pumps technology of heating and cooling." Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/34922.
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Increasing concern to society ecological and environmental issues, the demand for more efficient ways of using heat and energy is growing. Heat pump industry uses year-round heating with thermal energy. This concept is done by providing localized or redirected heat, by the exchange of cold air with the heated air.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34922
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VILAFRANCA, MANGUÁN ANA. "Convesion of industrial compression cooling to absorption cooling in an integrated district heating and cooling system." Thesis, University of Gävle, University of Gävle, Department of Technology and Built Environment, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4145.
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Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CHP plant was built. It is awarded with the electricity certificate system.
The study investigates the possibility for converting some of the compression cooling to absorption cooling and then analyzes the effects of the district heating system through MODEST optimizations. The effects of the analysis are studied in a system composed by the district heating system in Södertälje and cooling system in Astra Zeneca. In the current system the district heating production is from boiler and compression system supplies cooling to Astra Zeneca. The future system includes a CHP plant for the heating production, and compression system is converted to absorption system in Astra Zeneca. Four effects are analyzed in the system: optimal distribution of the district heating production with the plants available, saving fuel, environmental impact and total cost. The environmental impact has been analyzed considering the marginal electricity from coal condensing plants. The total cost is divided in two parts: production cost, in which district heating cost, purchase of electricity and Emissions Trading cost are included, and investment costs. The progressive changes are introduced in the system as four different scenarios.
The introduction of the absorption machines in the system with the current district heating production increases the total cost due to the low electricity price in Sweden. The introduction of the CHP plant in the district heating production supposes a profit of the production cost with compression system due to the high income of the electricity produced that is sold to the grid; it profit increases when compression is replaced by absorption system. The fuel used in the production of the future system decreases and also the emissions. Then, the future system becomes an opportunity from an environmental and economical point of view. At higher purchase electricity prices predicted in the open electricity market for an immediately future, the future system will become more economically advantageous.
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Chan, Hoy-Yen. "Solar facades for heating and cooling in buildings." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12319/.
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The aim of this thesis is to study the energy performance of a building integrated heating and cooling system. The research objectives are to investigate the system operating characters, to develop mathematical models for the heating and cooling systems, to demonstrate the technologies experimentally, to identify the best designs for a combined system and to investigate the cost effectiveness of the system. The main components of the systems are the aluminium plate façade and the building wall behind it, these form a plenum between them and the air is then heated or cooled as it flows through this plenum. Mathematical models were developed based on the energy balance equations and solved by matrix inversion method. These models were then validated with experimental results. The experiments were carried out in the laboratory with a facade area of 2m2. Two designs of facade were tested, i.e. flat and transpired plates. Results showed that the transpired design gave better thermal performance; the system efficiency for the flat plate was only about 30%, whereas it was about 85% for the transpired plate. On the other hand, a cooling system with double plenums was found to be better than a single plenum. Thus, a transpired plate with two plenums was identified as the best design for space heating and cooling. The cooling efficiency was nearly 2.0 even at low solar radiation intensity. A simulation study was carried out by assuming a 40m2 of façade was installed on an office building in London. The yearly energy saving was estimated as 10,877kWh, which is equivalent to 5,874kgCO2/year of emission avoidance. The system is calculated to cost about £70/m2, and for a discount rate of 5% and 30 years of lifetime, the payback period for this system would be less than a years.
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Sultan, Sahira. "Cost Evaluation of Building Space Heating; District Heating and Heat Pumps." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-37137.
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Climate change and energy efficiency has become a matter of concern in recent times; therefore, energy efficiency of buildings has drawn major attention. According to the European Commission, EU countries must improve energy efficiency of existing buildings by retrofitting and renovating the buildings. A case study of a renovated commercial building is considered in this degree project. A model of the building is developed in the IDA Indoor Climate and Energy (IDA ICE) software. The model is then augmented to include renovations in the building. Further, the model is simulated in IDA ICE before and after renovations to investigate the impact of renovations on energy consumption of the building for one year. The simulation results indicate peak demands of district heating that occur in the coldest days of the year. The peak demands of energy are expected to increase the district heating cost because they serve as a basis for new pricing model introduced by the energy providers. Hence, it is important from the customer point of view to reduce the peak loads for cost shavings. The project work also provides an insight into the alternative source of energy such as heat pumps to reduce the peak load demands of district heating.
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Markowicz, Catarina. "Analysis of Cooling Capability in Polish District Heating Substations." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173144.
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For a district heating company it is of importance to have an efficient and well performing system. A central part in the work to lower temperature levels in district heating networks is to acknowledge and improve cooling capability in substations. The aim of this thesis is to analyse substations in Polish district heating systems in order to identify reasons of poor cooling and to present suggestions of implementable measures. Furthermore, the economical saving potential from an improved cooling is evaluated. The analysis was carried out for two of the five Polish companies included in this report; Sydkraft EC Slupsk and MEC Koszalin. It was followed by two scenarios created for evaluation of improvement possibilities based on calculated financial savings from reduction of distribution heat losses and distribution pumping. The results show that there are significant improvement possibilities. From the carried out scenarios a saving potential between 15 000 to 20 000 PLN/substation is possible to achieve for selected worst substations, if their individual annual average cooling is set to 30°C. The analysis further shows that causes of poor cooling in substations are highly individual but points out that customer owned substations are represented in the majority of worst substations.
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Amara, Sofiane. "Novel and ancient technologies for heating and cooling buildings." Doctoral thesis, Luleå tekniska universitet, Arkitektur och vatten, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16977.
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The basic issue of this thesis concerns one of the fundamental problems of the future of our society: How to meet the energy requirements for a large and growing world population while preserving our environment? This question is important for the world and the answers are complex and interwoven.Conventional energy sources, fossil and fissile, are polluting in the present and in the future: they erode the environment and their resources are limited. Renewable energy (hydro, wind, solar, geothermal) constitutes a minimum of pollution in the different energy systems. The technologies for using renewable energy are well known though further development and progress are made. This development also requires behavioural change, adaptation, and above all political will. The transition from an economy based on fossil energy to an economy based on renewable energy appears necessary for the protection of the environment. The cost of renewable energy is often represented as an obstacle but remains competitive in the long run.The development and availability of renewable energy, which varies because of its spatial and temporal distribution, require an adaptation of lifestyle, habits, habitat design (passive bioclimatic houses), urban planning and transportation.The focus of this thesis was to apply renewable energy in an area with hot summers and cold winter, a climate like that in the northwest of Algeria. In order to provide improved comfort in the buildings and also economic development in this area, the energy demand for heating and cooling was analyzed in the ancient city of Tlemcen. To supply domestic hot water and space heating, water must be simultaneously available at two different temperature levels. Cold water temperature, close to that of the atmosphere, and hot water between 50 and 60°C. An interesting feature of the preparation of hot water is the small variation of requirements during the year, unlike that to heating. The preparation of hot water is one of the preferred applications of solar energy in the building for several reasons. For this reason an experimental study of the thermal behaviour of a domestic hot water storage tank was undertaken. The phenomena that affect the thermal behaviour of tank especially the coupling between the solar collector and storage tank was studied. This study included concentrating solar collector in which optical fibers were used to transport the energy to the storage tank. Another technology was introduced and developed for the heating and cooling of buildings in the desert involving an existing ancient irrigation system called Fouggara. The novel idea is to use the Fouggara as an air conditioner by pumping ambient air through this underground system. Then air at a temperature of about 21°C would be supplied to the building for heating in the winter and cooling in the summer. This study shows the feasibility of using this ancient irrigation system of Fouggara and contributes to reducing and eliminating the energy demand for heating and cooling buildings in the Sahara desert.Godkänd; 2011; 20110920 (sofama)
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Saman, Namir Fathullah. "Analysis of building heating and cooling requirements after shutdown." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184867.
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The heating and cooling requirements after a shutdown period of the heating ventilating and air conditioning (HVAC) systems in buildings are studied through an analytical model. The parameters affecting the preconditioning and storage loads which are of particular importance are identified. A mathematical computer model is developed to facilitate the analysis of the shutdown loads. Zones are grouped in terms of heavy, medium and light weight construction for the study. For a specified zone, the ratio of the inside surface area to the outside exposed area, A(s)/A(w), is an important parameter in predicting the additional loads resulting from system shutdown. The computer model is validated with known computer programs, namely DOE-2, BLAST, and DARE-P. A simplification to the model is proved to be adequate for the study. The zones with similar weight characteristics and the same A(s)/A(w) ratio, prove to have the same temperature profiles during the shutdown period, provided that they are at the same ambient conditions. Design guidance and procedures for predicting the preconditioning and storage loads using the models are developed. In addition, the use of DOE-2 and ASHRAE weighting factor method for shutdown load predictions is demonstrated for generic and custom applications.
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Afroz, Zakia. "Performance improvement of building heating, cooling and ventilation systems." Thesis, Afroz, Zakia (2019) Performance improvement of building heating, cooling and ventilation systems. PhD thesis, Murdoch University, 2019. https://researchrepository.murdoch.edu.au/id/eprint/54931/.
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Heating, Ventilation, and Air Conditioning (HVAC) systems are responsible for a substantial share of the energy consumed in commercial buildings. Energy used by HVAC systems has increased over the years due to its broader application in response to the growing demand for better thermal comfort within the built environment. While existing case studies demonstrate the energy saving potential of efficient HVAC operation, there is a lack of studies quantifying energy savings from optimal operation of HVAC systems when considering indoor environmental conditions. This research aims to improve the performance of HVAC systems by optimizing its energy consumption without compromising indoor environmental conditions.
The concept of maintaining indoor environmental conditions poses new challenges to the optimal operation of HVAC systems. While the primary objective of ensuring optimal operation is to minimize energy consumption, controlling the indoor environmental parameters, e.g., temperature, humidity, the level of carbon dioxide (CO2), and volatile organic compounds (VOCs) to remain within the acceptable range imposes excess energy use. These two conflicting objectives constitute a multi-variable constrained optimization problem that has been solved using a particle swarm algorithm (PSO).
A real-time predictive model has been developed for individual indoor environmental parameters and HVAC energy consumption using Nonlinear Autoregressive Exogenous (NARX) neural network (NN). During model development, efforts have been paid to optimize the performance of the model in terms of complexity, prediction results, and ease of application to a real system. The proposed predictive models are then optimized to provide an optimal control setting for HVAC systems taking into account seasonal variations. An extensive case study analysis has been performed in a real commercial building to demonstrate the effectiveness of developing predictive models and evaluating the relevance of integrating indoor air quality (IAQ) within the optimization problem.
Results show that it is possible to minimize 7.8% energy consumption from HVAC systems without compromising indoor environmental conditions. This study demonstrates that the proposed optimal control settings maintain the indoor environment within the acceptable limit of thermal comfort conditions (indoor air temperature between 19.60 to 28.20C and indoor air humidity between 30 to 65 %RH as per ASHRAE Standard 55-2017) and air quality (CO2 ≤ 800 ppm and VOC ≤ 1000ppm as per Australian Standard AS 1668.2 2016). The outcomes of this research will act as a guideline for energy management practices, not only for energy efficient building design and retrofitting but also for building energy performance analysis. This research provides insight into the aspects that affect the performance of predictive models for indoor temperature. The proposed feature selection approach establishes its efficacy to determine salient and independent input parameters without compromising prediction performance. The application of this approach will minimize the measurement and data storing cost of variables. Further, using fewer numbers of input parameters in the model will reduce the computational cost and time. Thus, the proposed model establishes its applicability in a real system for a more extended period of advanced prediction. In addition, the need to better account for building-occupant interactions as an important step to maintain a healthy indoor environment has been recognized through evaluating a real-life demand control (DCV) system. Lastly, the proposed optimization approach, where four defined environmental parameters are considered simultaneously presents a new outlook within the HVAC control system by eliminating the unseen interface between thermal comfort and IAQ.
Overall, this unexploited potential to simultaneously improve the performance of HVAC systems and indoor environmental conditions drives the discussion on reconsidering the set-point configuration standards of HVAC in commercial buildings, either as part of individual building retrofit planning or as part of building regulatory applications.
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Alharbi, Abdulrahman. "Investigation of sub-wet bulb temperature evaporative cooling system for cooling in buildings." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27806/.
Full textAbstract:
The work presented in this thesis investigates design, computer modelling and testing a sub-wet bulb temperature evaporative cooling system for space air conditioning in buildings. The context of this evaporative cooling technology design is specifically targeted at locations with a hot and dry climate such as that prevailing in most regions of Middle East countries. The focus of this technology is to address the ever-escalating energy consumption in buildings for space cooling using mechanical vapour compression air conditioning systems. In this work, two evaporative cooling configurations both based on sub-wet bulb temperature principle have been studied. Furthermore, in these designs, it was sought to adopt porous ceramic materials as wet media for the evaporative cooler and as building element and use of heat pipes as heat transfer devices. In the first test rig, the prototype system uses porous ceramic materials as part of a functioning building wall element. Experimental and modelling results were obtained for ambient inlet air dry bulb temperature of 30 and 35oC, relative humidity ranging from 35% to 55% and intake air velocity less than 2 (m/s). It was found that the design achieved sub-wet bulb air temperature conditions and a maximum cooling capacity approaching 242 W/m2 of exposed ceramic material wet surface area. The wet bulb effectiveness of the system was higher than unity. The second design exploits the high thermal conductivity of heat pipes to be integrated as an effective heat transfer device with wet porous ceramic flat panels for evaporative cooling. The thermal performance of the prototype was presented and the computer model was validated using laboratory tests at temperatures of 30 and 35oC and relative humidity ranging from 35% to 55%. It was found that at airflow rates of 0.0031kg/s, inlet dry-bulb temperature of 35oC and relative humidity of 35%, the supply air could be cooled to below the inlet air wet bulb temperature and achieve a maximum cooling capacity of about 206 W/m2 of wet ceramic surface area. It was shown that the computer model and experimental tests are largely in good agreement. Finally, a brief case study on direct evaporative cooling thermal performance and environmental impact was conducted as part of a field trip study conducted on an existing large scale installation in Mina Valley, Saudi Arabia. It was found that the evaporative cooling systems used for space cooling in pilgrims’ accommodations and in train stations could reduce energy consumption by as much as 75% and cut carbon dioxide emission by 78% compared to traditional vapour compression systems. This demonstrates strongly that in a region with a hot and dry climate such as Mina Valley, evaporative cooling systems can be an environmentally friendly and energy-efficient cooling system compared to conventional vapour compression systems.
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Al-Hinai, Hilal Ali Zaher. "Natural Cooling Techniques For Buildings." Thesis, Cranfield University, 1992. http://hdl.handle.net/1826/3591.
Full textAbstract:
Modern development in many Third World countries in the
hot regions of the world,, have been accompanied by the
construction of highly energy-wasteful buildings. The
interiors of these buildings have to be mechanically airconditioned
in order to achieve thermal-comfort conditions.
The consequence of this, has been the rapid increase in
electricity-generating plant capacity to match demand (of
which, for example at present in Oman, more than 70%
nationally is used for air-conditioning modern, energyinefficient
buildings).
The aim of this work was to find the most suitable way
of stabilising or even reducing the electricity demand in a
country like Oman. The first step taken to achieve this aim,
was to study and draw out lessons from the vernacular
architecture of the different climatic regions in Oman. This
has been followed by a literature survey that looks at
passive and active natural cooling techniques for buildings
in hot climates. Mathematical models were then developed to
analyze and compare those passive techniques that are most
suitable for an environment like that of Oman. Different ways
of reducing the heat gain through the roof were investigated
and compared. These include the addition of insulation,
shading, air-cooling of the roof when the ambient air
temperature is lower than that of the roof, and roof ponds.
Roof ponds were found to be the most effective of those
techniques analyzed. An improved design of the roof pond (the
Water Diode roof pond) that eliminates the need for covering
the roof pond during the day and uncovering it at night, was
suggested and analyzed. The analysis showed promising
results. Mathematical models were also developed to analyze and
compare dif f erent ways of reducing the heat gain through the
walls. These included the use of closed cavities, naturally
ventilated cavities, the addition of insulation, and the
effect of using brick as compared to concrete block. The
analysis suggested that the combination of a Water Diode roof
pond and insulated brick wall construction will reduce the
heat gain through the envelope of a single room by more than
90%, when compared to a room with un-insulated roof and
single-leaf concrete block walls.
An empirical validation of the mathematical models was
conducted. The results showed a good agreement between the
actual and predicted values. An economical analysis of the
commonly used roof and wall constructions in Oman, was also
conducted. This compared the life-cycle cost of nine
different construction techniques, with eight different airconditioning
schedules. The result of this analysis showed a
clear advantage of using roof insulation, reflective double
glazing, and insulated walls with brick outer-leaf and
concrete block inner-leaf.
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Clark, Craig R. "Sympathetic heating and cooling of trapped atomic and molecular ions." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43757.
Full textAbstract:
Laser-cooled atomic ions have led to an unprecedented amount of control over the quantum states of matter. The Coulombic interaction allows for information to be transferred between neighboring ions, and this interaction can be used to entangle qubits for logic operations in quantum information processors. The same procedure for logic operations can be used for high resolution atomic spectroscopy, and is the basis for the most accurate atomic optical clocks to date. This thesis describes how laser-cooled atomic ions can impact physical chemistry through the development of molecular ion spectroscopy techniques and the simulation of magnetic systems by ion trap quantum computers.
A new technique developed for spectroscopy, Sympathetic Heating Spectroscopy (SHS), takes advantage of the Coulombic interaction between two trapped ions: the control ion and a spectroscopy ion. SHS uses the back action of the interrogating laser to map spectroscopy ion information onto the Doppler shift of the control ion for measurement. SHS only requires Doppler cooling of the ions and fluorescence measurement and represents a simplification of quantum logic spectroscopy. This technique is demonstrated on two individual isotopes of calcium: Ca-40(+) for cooling and Ca-44(+) as the spectroscopy ion.
Having demonstrated SHS with atomic ions, the next step was to extend the technique by loading and characterizing molecular ions. The identification of an unknown molecular ion is necessary and can be achieved by monitoring the change in motion of the two ion crystal, which is dependent on the molecular ion mass. The motion of two trapped ions is described by their normal modes, which can be accurately measured by performing resolved sideband spectroscopy of the S(1/2)-D(5/2) transition of calcium. The resolved sidebands can be used to identify unknown ions (atomic and molecular) by calculating the mass based on the observed value in axial normal mode frequencies. Again, the trapped molecular ion is sympathetically cooled via the Coulombic interaction between the Ca-40(+) and the unknown molecular ion. The sensitivity of SHS could be improved by implementing sympathetic sideband cooling and determining the heating by measuring single quanta of motion.
The ultimate limit of control would be the development of an ion trap quantum computer. Many theoretical quantum computing researchers have made bold claims of the exponential improvement a quantum computer would have over a classical computer for the simulation of physical systems such as molecules. These claims are true in principle for ideal systems, but given non-ideal components it is necessary to consider the scaling due to error correction. An estimate of the resource requirements, the total number of physical qubits and computational time, required to compute the ground state energy of a 1-D quantum Transverse Ising Model (TIM) of N spin-1/2 particles, as a function of the system size and the numerical precision, is presented. This estimate is based on analyzing the impact of fault-tolerant quantum error correction in the context of the quantum logic array architecture. The results show that a significant amount of error correction is required to implement the TIM problem due to the exponential scaling of the computational time with the desired precision of the energy. Comparison of this result to the resource requirements for a fault-tolerant implementation of Shor's quantum factoring algorithm reveals that the required logical qubit reliability is similar for both the TIM problem and the factoring problem.
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Marigny, Johan. "Analysis of simultaneous cooling and heating in supermarket refrigeration systems." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-44469.
Full textAbstract:
In this master thesis project, conventional supermarket refrigeration systems using R404A are compared with refrigeration system solutions using natural refrigerants such as carbon dioxide and ammonia. This systems analysis considers the behavior of those systems in floating condensing and heat recovery mode. System heating and cooling COP have been calculated by using computer simulation with the calculation software EES (Engineering Equation Solver). The impact of important parameters such as sub-cooling, external superheating and compressor discharge was also determined through the computer models.The estimation of the system annual energy consumptions shows that systems using natural refrigerant can compete with systems using artificial refrigerant by using heat recovery system such as heat pump cascade, heat pump cascade for sub-cooling, fixed pressure system and de-superheater. If the indirect emission of systems using natural refrigerant and artificial refrigerant is approximately similar, the direct emission for carbon dioxide systems and ammonia systems can be estimated to be 10000 times less important than R404A systems.Multi-unit refrigeration systems have also been studied in this project; it appears that in theory COP improvement of 10% is possible if the condensing temperature of each unit is controlled adequatelly.B
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Mert, Cuce Ayse Pinar. "Innovative heating, cooling and ventilation technologies for low-carbon buildings." Thesis, University of Nottingham, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716485.
Full textAbstract:
Sectoral energy consumption analyses clearly indicate that building sector plays a key role in global energy consumption, which is almost 40% in developed countries. Among the building services; conventional heating, ventilation and air conditioning (HVAC) systems have the greatest percentage in total energy consumption of buildings. According to the latest research, HVAC is responsible for around 40% of total building energy consumption and 16% of total global energy consumption. In this respect, decisive measures need to be taken to mitigate the energy consumption due to HVAC. The research carried out within the scope of this thesis covers innovative heating, cooling and ventilation technologies for low-carbon buildings. The novel technologies developed are introduced and investigated both theoretically and experimentally. The results indicate that optimised HVAC systems with waste heat recovery have a significant potential to mitigate energy consumed in buildings, thus to halt carbon emissions. Especially plate-type roof waste heat recovery units are very attractive for the said hybrid applications with a thermal efficiency greater than 88%. The said systems are also promising in terms of overall coefficient of performance (COP). The average COP of plate-type roof waste heat recovery unit is determined to be about 4.5, which is incomparable with those of conventional ventilation systems. Preheating performance of fresh air in winter season is found to be remarkable. Comprehensive in- situ tests clearly reveal that the temperature rise in fresh air is found to be around 7 °C. Plate-type roof waste heat recovery units also provide thermal comfort conditions for occupants. Indoor CCE concentration is observed to be varying from 350 to 400 ppm which is very appropriate in term of air quality. In addition, average relative humidity is found to be 57%, which is in the desired range according to the latest building standards. Desiccant-based evaporative cooling systems are capable of providing Abstract desired indoor environments for occupants as well as having considerably high COP ranges. An average of 5.3 °C reduction is achieved in supply air temperature by utilising those systems as well as having relative humidity distribution in thermal comfort range. The dehumidification effectiveness is found to be 63.7%, which is desirable and promising. The desiccant-based evaporative cooling system has a great potential to mitigate cooling demand of buildings not only in hot arid but also in temperate humid climates.
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Oliver, Jason Ryan. "A micro-COOLING, HEATING, AND POWER (m-CHP) INSTRUCTIONAL MODULE." MSSTATE, 2005. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11092005-123751/.
Full textAbstract:
Cooling, Heating, and Power (CHP) is an emerging category of energy systems consisting of power generation equipment coupled with thermally activated components. The application of CHP systems to residential and small commercial buildings is known as micro-CHP (m-CHP). This instructional module has been developed to introduce engineering students to m-CHP. In the typical engineering curriculum, a number of courses could contain topics related to m-CHP. Thermodynamics, heat transfer, HVAC, heat and power, thermal systems design, and alternate energy systems courses are appropriate m-CHP topics. The types of material and level of analysis for this range of courses vary. In thermodynamics or heat transfer, basic problems involving a m-CHP flavor are needed, but in an alternate energy systems course much more detail and content would be required. This instructional module contains both lecture material and a compilation of problems/exercises for both m-CHP systems and components.
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Nijmeh, Salem Daud. "Solar chemical heat pumps for heating and cooling in Jordan." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303147.
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Buker, Mahmut Sami. "Building integrated solar thermal collectors for heating & cooling applications." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29009/.
Full textAbstract:
International Energy Agency Solar Heating & Cooling (IEA SHC) programme states the fact that space/water heating and cooling demand account for over 75% of the energy consumed in single and multi-family homes. Solar energy technology can meet up to 100% of this demand depending on the size of the system, storage capacity, the heat load and the region’s climate. Solar thermal collectors are particular type of heat extracting devices that convert solar radiation into thermal energy through a transport medium or flowing fluid. Although hybrid PV/T or thermal-alone systems offer some advantages to improve the solar heat utilisation, there are a few technical challenges found in these systems in practice that prevented wide-scale applications. These technical drawbacks include being expensive to make and install, inability of switching already-built photovoltaic (PV) systems into PV/T systems, architectural design etc. The aims of this project, therefore, were to investigate roof integrated solar thermal roof collectors that properly blend into surrounding thus avoiding ‘add on’ appearance and having a dual function (heat absorption and roofing). Another objective was to address the inherent technical pitfalls and practical limitations of conventional solar thermal collectors by bringing unique, inexpensive, maintenance free and easily adaptable solutions. Thus, in this innovative research, unique and simple building integrated solar thermal roof collectors have been developed for heating & cooling applications. The roof systems which mainly based on low cost and structurally unique polyethylene heat exchanger are relatively cost effective, competitive and developed by primarily exploiting components and techniques widely available on the market. The following objectives have been independently achieved via evaluating three aspects of investigations as following: • Investigation on the performance of poly heat exchanger underneath PV units • Investigation on the performance of a Building Integrated PV/T Roof ‘Invisible’ Collector combined with a liquid desiccant enhanced indirect evaporative cooling system • Investigation on the build-up and performance test of a novel ‘Sandwich’ solar thermal roof for heat pump operation These works have been assessed by means of computer simulation, laboratory and field experimental work and have been demonstrated adequately. The key findings from the study confirm the potential of the examined technology, and elucidate the specific conclusions for the practice of such systems. The analysis showed that water temperature within the poly heat exchanger loop underneath PV units could reach up to 36°C and the system would achieve up to 20.25% overall thermal efficiency. Techno-economic analysis was carried out by applying the Life Cycle Cost (LCC) method. Evaluations showed that the estimated annual energy savings of the overall system was 10.3 MWh/year and the cost of power generation was found to be £0.0622 per kWh. The heat exchanger loop was coupled with a liquid desiccant enhanced indirect evaporative cooling unit and experimental results indicated that the proposed system could supply about 3 kW of heating and 5.2 kW of cooling power. Lastly, the results from test of a novel solar thermal collector for heat pump operation presented that the difference in water temperature could reach up to 18°C while maximum thermal efficiency found to be 26%. Coefficient Performance of the heat pump (COPHP) and overall system (COPSYS) averages were attained as COPHP=3.01 and COPSYS=2.29, respectively. An economic analysis pointed a minimum payback period of about 3 years for the system.
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Uhrík, Patrik. "Implementace kogeneracni jednotky do siti "Smart Heating and Cooling Networks"." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318635.
Full textAbstract:
The aim of the Master‘s thesis was to create a computational model for integration of the cogeneration unit into the smart thermal network. For the better use of waste heat from the selected cogeneration unit MOTORGAS MGM250 during the summer period, the absorption circuit was dimensioned and the appropriate trigeneration computational model was formed. In the theoretical part, the function, operation and heat performance of the cogeneration unit as well as the suitability of the connection of the cogeneration unit with the absorption chiller during the summer period were described. In the practical part, the operational data of the Faculty of Mechanical Engineering of the Brno University of Technology and the theoretical performance data from created cogeneration and trigeneration computational models were compared. Based on this comparison, the conclusion about the suitability of use of both computational models was made.
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Lo, S. N. G. "Passive solar space and water heating systems." Thesis, Cranfield University, 1990. http://hdl.handle.net/1826/3935.
Full textAbstract:
The performance of three types of passive solar
feature has been studied; fifteen Roof-Space
Collectors on an estate of low energy houses at the
Milton Keynes Energy Park, 101m2 of Thermosyphoning
Air Panels at a county primary school in Nazeing,
Essex, and three Thermosyphon Solar Water Heaters
installed on a group of three terraced cottages at
Cranfield, Bedfordshire. Each of these passive solar
features was monitored intensively for at least one
heating season using dedicated data-acquisition
systems. The maximum specific annual solar
contributions to the auxiliary space/water heating
systems were 128 kWh/M2
,
78 kWh/M2' and 104 kWh/M2
respectively. The corresponding payback periods were
25,37 & 21 years respectively, on replication.
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Ryjkov, Vladimir Leonidovich. "Laser cooling and sympathetic cooling in a linear quadrupole rf trap." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1637.
Full textAbstract:
An investigation of the sympathetic cooling
method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of
rf heating rates on the ion temperature, trapping parameters,
and the number of ions is obtained. New rf heating mechanism
affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra
of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of
the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and
the influence of the rf heating rates on the fluorescence lineshapes
is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.
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Stene, Jørn. "Residential CO2 Heat Pump System for Combined Space Heating and Hot Water Heating." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-382.
Full textAbstract:
Carbon dioxide (CO2, R-744) has been identified as a promising alternative to conventional working fluids in a number of applications due to its favourable environmental and thermophysical properties. Previous work on residential CO2 heat pumps has been dealing with systems for either space heating or hot water heating, and it was therefore considered interesting to carry out a theoretical and experimental study of residential CO2 heat pump systems for combined space heating and hot water heating – so-called integrated CO2 heat pump systems. The scope of this thesis is limited to brine-to-water and water-to-water heat pumps connected to low-temperature hydronic space heating systems..
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Liu, Shuli. "A novel heat recovery/desiccant cooling system." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/11602/.
Full textAbstract:
The global air temperature has increased by 0.74± 0.18 °C since 1905 and scientists have shown that CO2 accounts for 55 percentages of the greenhouse gases. Global atmospheric CO2 has been sharply increased since 1751, however the trend has slowed down in last fifty years in the Western Europe. UK and EU countries have singed the Kyoto agreement to reduce their greenhouse gas emissions by a collective average of 12.5% below their 1990 levels by 2020. In the EU, 40% of CO2 emission comes from the residential energy consumption, in which the HVAC system accounts for 50%, lighting accounts for 15% and appliances 10%. Hence, reducing the fossil-fuel consumption in residential energy by utilizing renewable energy is an effective method to achieve the Kyoto target. However, in the UK renewable energy only accounts for 2% of the total energy consumption in 2005. A novel heat recovery/desiccant cooling system is driven by the solar collector and cooling tower to achieve low energy cooling with low CO2 emission. This system is novel in the following ways: • Uses cheap fibre materials as the air-to-air heat exchanger, dehumidifier and regenerator core • Heat/mass fibre exchanger saves both sensible and latent heat from the exhaust air • The dehumidifier core with hexagonal surface could be integrated with windcowls/catchers draught • Utilises low electrical energy and therefore low CO2 is released to the environment The cooling system consists of three main parts: heat/mass transfer exchanger, desiccant dehumidifier and regenerator. The fibre exchanger, dehumidifier and regenerator cores are the key parts of the technology. Owing to its proper pore size and porosity, fibre is selected out as the exchanger membrane to execute the heat/mass transfer process. Although the fibre is soft and difficult to keep the shape for long term running, its low price makes its frequent replacement feasible, which can counteract its disadvantages. A counter-flow air-to-air heat /mass exchanger was investigated and simulation and experimental results indicated that the fibre membranes soaked by desiccant solution showed the best heat and mass recovery effectiveness at about 89.59% and 78.09%, respectively. LiCl solution was selected as the working fluid in the dehumidifier and regenerator due to its advisable absorption capacity and low regeneration temperature. Numerical simulations and experimental testing were carried out to work out the optimal dehumidifier/regenerator structure, size and running conditions. Furthermore, the simulation results proved that the cooling tower was capable to service the required low temperature cooling water and the solar collector had the ability to offer the heating energy no lower than the regeneration temperature 60℃. The coefficient-of-performance of this novel heat recovery/desiccant cooling system is proved to be as high as 13.0, with a cooling capacity of 5.6kW when the system is powered by renewable energy. This case is under the pre-set conditions that the environment air temperature is 36℃ and relative humidity is 50% (cities such as Hong Kong, Taiwan, Spain and Thailand, etc). Hence, this system is very useful for a hot/humid climate with plenty of solar energy. The theoretical modelling consisted of four numerical models is proved by experiments to predict the performance of the system within acceptable errors. Economic analysis based on a case (200m2 working office in London) indicated that the novel heat recovery/desiccant cooling system could save 5134kWh energy as well as prevent 3123kg CO2 emission per year compared to the traditional HVAC system. Due to the flexible nature of the fibre, the capital and maintenance cost of the novel cooling system is higher than the traditional HVAC system, but its running cost are much lower than the latter. Hence, the novel heat recovery/desiccant cooling system is cost effective and environment friendly technology.
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Chen, Xiangjie. "Investigations of heat powered ejector cooling systems." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/29721/.
Full textAbstract:
In this thesis, heat powered ejector cooling systems was investigated in two ways: to store the cold energy with energy storage system and to utilize low grade energy to provide both electricity and cooling effect. A basic ejector prototype was constructed and tested in the laboratory. Water was selected as the working fluid due to its suitable physical properties, environmental friendly and economically available features. The computer simulations based on a 1-0 ejector model was carried out to investigate the effects of various working conditions on the ejector performance. The coefficients of performance from experimental results were above 0.25 for generator temperature of lI5°C-130 °C, showing good agreements with theoretical analysis. Experimental investigations on the operating characteristics of PCM cold storage system integrated with ejector cooling system were conducted. The experimental results demonstrated that the PCM cold storage combined with ejector cooling system was practically applicable. The effectiveness-NTU method was applied for characterizing the tube-in-container PCM storage system. The correlation of effectiveness as the function of mass flow rate was derived from experimental data, and was used as a design parameter for the PCM cold storage system. In order to explore the possibility of providing cooling effect and electricity simultaneously, various configurations of combined power and ejector cooling system were studied experimentally and theoretically. The thermal performance of the combined system in the range of 0.15-0.25 and the turbine output between 1200W -1400W were obtained under various heat source temperatures, turbine expansion ratios and condenser temperatures. Such combined system was further simulated with solar energy as driving force under Shanghai climates, achieving a predicted maximum thermal efficiency of 0.2. By using the methods of Life Saving Analysis, the optimized solar collector area was 30m2 and 90m2 respectively for the system without and with power generation. The environmental impacts and the carbon reductions of these two systems were discussed.
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Twort, Charles Tyler. "An exergy analysis of mine cooling systems." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323333.
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Mohamed, Y. "Interactive analysis of power station cooling systems." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380600.
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Petters, Jonathan L. Clothiaux Eugene. "The impact of radiative heating and cooling on marine stratocumulus dynamics." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4602/index.html.
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Grüner, Florian. "Experiments and simulation of transverse cooling and heating in ion channeling." Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-16339.
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Hardy, John David. "A Cooling, Heating, and Power for Buildings (CHP-B) Instructional Module." MSSTATE, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04082003-030901/.
Full textAbstract:
An emerging category of energy systems, consisting of power generation equipment coupled with thermally-activated components, has evolved as Cooling, Heating, and Power (CHP). The application of CHP systems to buildings has developed into a new paradigm ? Cooling, Heating, and Power for Buildings (CHP-B). This instructional module has been developed to introduce undergraduate engineering students to CHP-B. In the typical ME curriculum, a number of courses could contain topics related to CHP. Thermodynamics, heat transfer, thermal systems design, heat and power, alternate energy systems, and HVAC courses are appropriate for CHP topics. However, the types of material needed for this mix of courses vary. In thermodynamics, basic problems involving a CHP flavor are needed, but in an alternate energy systems course much more CHP detail and content would be required. This series of lectures on CHP-B contains both a stand-alone CHP treatment and a compilation of problems/exercises.
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Gurjer, Yeshwant Ramesh. "Use of Heat Pumps for Heating and Night Cooling of Greenhouses." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20011105-182143.
Full textAbstract:
Gurjer, Yeshwant Ramesh. Use of Heat Pumps for Heating and Night Cooling of Greenhouses. (under the direction of Daniel H. Willits). The use of heat pumps for heating and night cooling of greenhouses was investigated using a computer simulation program and weather data from Typical Meteorological Year (TMY2) datasets for Raleigh, NC, and Wilmington, NC. A greenhouse computer model taken from the literature, along with the heat pump subroutines (HPHEAT and HPCOOL) developed in this study, were used for the simulations. The use of heat pumps for heating only, and for heating plus night cooling, were examined separately using both standard and time-of-use electricity rates for two North Carolina utility providers. When heat pumps were used only for heating, standard electricity rates were predicted to provide greater savings in utility costs compared to time-of-use rates. When heat pumps were used for both heating and night cooling, the predicted savings in utility costs was greater for time-of-use electricity rates. Night cooling was predicted to decrease the average daily temperature (0.10C to 1.10C) and average nighttime temperature (0.10C to 2.00C) inside the greenhouse providing the potential for increased yield. Although a heat pump of capacity 36.5 W/m2 of floor area provided less savings in total costs compared to a capacity of 76 W/m2, the heat pump with the smaller capacity (36.5 W/m2) may be a better proposition because of the lower purchase cost.
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Kizikoglu, Atahan Riza. "Thermo-Economic Analysis of Solar Cooling/Heating Systems for Mediterranean Climates." Thesis, KTH, Kraft- och värmeteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161065.
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This study focuses on the efficient use of solar energy for a certain region in the Mediterranean basin. Solar thermal energy becomes increasingly popular and the available solar market is investigated with the aim of selecting and assessing a pilot region for a promising solar application. The work herein focuses on estimating the potential of three different 100% solar-driven integrated systems to cover the entire cooling and heating demand of a selected single family house solely by solar energy. The three different alternative systems are presented and examined in detail for the actual case study application. The sample house within the chosen region is located on the south coast of Turkey. The entire thermal demand of this house for both cooling during summer and heating during winter has first been properly calculated. Characteristic features of the house and the typical design parameters for the region have been analyzed, as well as and their daily and annual variations. Heat loss and heating/cooling load calculations have been done with respect to these specifications and to ASHRAE regulations. After finding the building`s demands for the comfort temperature, the three different solar-driven systems are simulated for a practical application to the sample house. Required mechanical equipment and parasitic load consumption has been investigated for each system and investment cost analyses have been performed respectively. Simplified payback times for each alternative system are calculated and discussed. Payback period sensitivity analysis was attempted for two different locations featuring different grid pricing regulations. As a conclusion, feasibility analysis for the three examined types of solar-driven integrated heating and cooling systems has been attempted, which gives a good representation of the potential solar energy market in the Mediterranean region. Also some suggestions are offered to the companies which develop and market solar heating/cooling systems.
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CAMPOS, SERGIO LIBANIO DE. "DEVELOPMENT OF AN AUTOMOTIVE AIR CONDITIONING SYSTEM FOR HEATING AND COOLING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24641@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROSistemas condicionadores de ar automotivos têm sido extensivamente estudados, buscando melhor eficiência de resfriamento e redução do consumo de combustível. O presente trabalho tem como objetivo o estudo de um sistema condicionador de ar automotivo operando nos modos de resfriamento e aquecimento, este último atendendo às necessidades de conforto em dias frios nos veículos elétricos, os quais não apresentam calor de rejeito do motor, como nos veículos convencionais. Para tal foi projetado e montado, no Laboratório de Refrigeração, Condicionamento de Ar e Criogenia da PUC-Rio, um aparato experimental composto por duas câmaras de temperatura e umidade controladas, uma simulando o compartimento de passageiros e a outra, o ambiente externo. Um típico sistema condicionador de ar automotivo, composto por componentes comercialmente disponíveis e utilizados nos veículos atuais, foi dotado de válvulas direcionais, permitindo a inversão do ciclo de compressão de vapor do modo de resfriamento para o modo de aquecimento, operando neste último como bomba de calor. Dados experimentais foram levantados sob operação em regime permanente e transiente (período de partida), com temperaturas entre – 5 graus Celcius e 45 graus Celcius. Para o modo de resfriamento, seguiu-se a norma SAE J2765 e, para o de aquecimento, na ausência de normas, foram cobertas as operações em modos de recirculação do ar da cabine e de renovação com ar externo, entre as temperaturas de -5 graus Celcius e 10 graus Celcius. Foi também realizada uma simulação numérica, validada pelos dados experimentais, utilizando as equações fundamentais da termodinâmica e transferência de calor. O sistema testado mostrou-se viável na aplicação em veículos elétricos, uma vez que nestes o calor de rejeito previsto (regeneração de frenagem e efeito Joule na eletrônica de potência) não é suficiente para o conforto térmico em dias frios. Demonstrou-se que a bomba de calor consome menos energia que resistências as elétricas atualmente utilizadas.
Automotive air conditioning systems have been extensively studied, searching for better cooling efficiency and reduced fuel consumption. The present work aims to study a system of automotive air conditioner operating in cooling and heating modes, the latter satisfies the needs of comfort on cold days in electrical vehicles, which do not include waste heat from the engine as the conventional vehicles. To this was designed and assembled in the Refrigeration, Air Conditioning and Cryogenics Laboratory, in Puc-Rio, an experimental apparatus consists of two chambers with temperature and humidity controlled, one, simulating the passenger compartment and the other, the external environment. A typical automotive air conditioning system, composed of commercially available components used in current vehicles is provided with a directional valve, allowing the inversion of vapor compression cooling mode to the heating mode cycle, the latter operating as a heat pump.
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Boufadel, George Fadlo. "Dynamic thermal response of buildings resulting from heating and cooling interruptions." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/74757.
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Transient modelling of heat fluxes and temperatures in structures was conducted to examine the effect of various characteristics on the temperature response during unusual operating and extreme weather conditions. The analytical model was validated using published experimental data and numerical results from well-known computer codes.
The effect of including radiation heat transfer between interior surfaces, using the Mean Radiative Temperature method, on the temperature response was investigated and found to be negligible for a typical commercial building and a house during winter and summer power outages.
The effect of thermal mass in the interior and exterior walls on the inside temperature drift after an HVAC system cutoff or a power outage was presented. The inside air temperature response curve is presented for different wall (exterior or interior) constructions of buildings. The effect of insulation position in exterior walls was also shown for several R values. The effect of exterior wall emissivity, sky temperature, outside vertical convective coefficient, furnishings, and ground temperature on the interior temperature response during winter and summer power outages were examined for buildings.
The effect of infiltration on the temperature drift in buildings was investigated during winter and summer power outages. Restarting the HVAC after the power outage was examined during both seasons for typical buildings.
Outside temperature profiles exceeding the 97.5 design temperature criterion were used to study the effect of extreme weather on the interior temperature of buildings with the HVAC system operating.Ph. D.
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Chou, Lu-chien. "Drag reducing cationic surfactant solutions for district heating and cooling systems /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487758178238587.
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Aoun, Nadine. "Modeling and flexible predictive control of buildings space-heating demand in district heating systems." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC104.
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La gestion de la demande en chauffage des bâtiments raccordés à des réseaux de chaleur s'effectue classiquement au moyen d’une courbe de chauffe : lorsque la température extérieure chute, la température de départ de l’eau alimentant le circuit de chauffage interne est relevée. Ce mode de contrôle, appelé régulation par loi d’eau, présente des atouts en termes de simplicité et de robustesse, mais ne tient pas compte de l'inertie thermique du bâtiment et ne permet donc pas une modulation de sa demande. La modulation de la demande en chauffage se définit comme l'action de contrôle consistant à modifier de manière stratégique les conditions de confort thermique dans le cadre d’une optimisation énergétique et/ou économique. Il s’agit d’une brique essentielle du contrôle flexible qui envisage le déplacement des charges et l’effacement des pics pour une meilleure efficacité de production favorisant la pénétration des énergies renouvelables et de récupération.Ces travaux de thèse visent à développer une stratégie de contrôle prédictif et flexible de la demande en chauffage, applicable à grande échelle dans les réseaux de chaleur.Tout d'abord, un simulateur thermique dynamique de bâtiment résidentiel, équipé de radiateurs hydrauliques connectés à une sous-station de réseau de chaleur, est développé. Il permet de définir plusieurs cas d’études de bâtiments représentatifs du parc résidentiel français et constitue l’environnement expérimental virtuel de nos travaux de recherche. Ensuite, une méthodologie permettant d’obtenir un modèle orienté-contrôle et d’ordre réduit de bâtiment avec son système de chauffage est proposée. Elle commence par la définition de la structure du modèle en se basant sur des connaissances physiques, puis consiste en l'identification des paramètres par optimisation méta-heuristique à l'aide des données générées par le simulateur. L'approche d'identification paramétrique évalue la possibilité de réaliser cette tâche en ne s’appuyant que sur des données disponibles au niveau de la sous-station, notamment en s’interdisant d’utiliser des mesures de température intérieure au bâtiment, donnée à caractère personnel présumée indisponible à grande échelle pour des raisons techniques, économiques et juridiques. Enfin, la stratégie de contrôle prédictif est implémentée. Elle permet la planification de la température de départ de l'eau de chauffage en fonction des prévisions météorologiques et des prix de l’énergie. Le contrôleur flexible s’appuie sur un problème d’optimisation linéaire sous contraintes, selon le principe de l’horizon fuyant. Il incorpore les équations linéarisées du modèle d’ordre réduit et calcule le compromis optimal entre coûts énergétiques et inconfort thermique, le degré de flexibilité de la demande en chauffage étant défini par l’intermédiaire de paramètres de réglage dédiésIn District Heating Systems (DHSs), buildings Space-Heating (SH) demand management conventionally relies on a heating curve: when the outdoor temperature drops, the internal SH system supply water temperature is raised. This control mode, referred to as Weather-Compensation Control (WCC), offers widely recognized assets in terms of simplicity and robustness. However, WCC does not account for the building thermal inertia, and consequently, it does not allow modulation of its demand. SH demand modulation is the control action of strategically altering the indoor thermal comfort conditions within an energetic and/or economic optimization framework. It is a key measure in flexible demand control strategies, which seek loads shifting and peaks shaving to allow sustainable commitment of energy resources in favour of renewable power penetration and waste heat recovery.The work presented in this thesis aims at developing a flexible Model Predictive Control (MPC) strategy for SH demand, applicable at large scale in DHSs.Firstly, a thermal dynamic simulator of a residential building with a radiator SH circuit connected to a DHS substation is developed. It allows the definition of multiple case study buildings, well-representative of the french residential stock, and constitutes the virtual experimental environment for our research. Then, a methodology to obtain a control-oriented Reduced-Order Model (ROM) for the building and its SH system is proposed. It starts by defining the ROM structure based on physical knowledge, and proceeds to parameters identification by meta-heuristic optimization using data generated by the simulator. The parametric identification approach evaluates the possibility of carrying out this task by relying solely on data available at the substation level, refraining from using indoor temperature measurements, personal data assumed to be unavailable at large scale for technical, economic and legal reasons. Finally, MPC is implemented to schedule the SH supply water temperature as function of weather forecasts and energy price variations. The flexible controller is designed to solve a constrained linear optimization problem according to the receding horizon principle. It embeds the linearized ROM equations within the problem formulation and makes an optimal trade-off between energy consumption costs and thermal discomfort, the degree of flexibility to modulate SH demand being defined through dedicated tuning parameters
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Jerome, David. "Building load analysis and graphical display as a design tool." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/16410.
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Cleaveland, John P. "Loadcal : a microcomputer simulation for estimating heating and cooling loads for commercial buildings." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/23099.
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Skogsberg, Kjell. "Seasonal snow storage for space and process cooling /." Luleå, 2005. http://epubl.luth.se/1402-1544/2005/30.
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Gatts, Timothy J. "Investigation of the heating and cooling of composite glass seals for SOFCs." Connect to resource, 2008. http://hdl.handle.net/1811/32060.
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Kilpatrick, Yvonne Younis. "Daylighting and high efficiency lighting : the effects on heating and cooling loads." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/21810.
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Yuwardi, Yuwardi. "Absorption cooling in district heating network: Temperature difference examination in hot water circuit." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-125068.
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Absorption cooling system driven by district heating network is relized as a smart strategy in Sweden. During summer time when the heating demand is low, the excessive hot water can be directly sold to drive absorption chillers instead of decreasing its production. In addition, this is also one answer to satisfy the cooling demand in more environmentally way since currently only around 26% of cooling demand in Sweden is satisfied by district cooling, the rest is fulfilled by individual air conditioning. Realizing this potential, the purpose of this study is to examine the returning hot water temperature in the district heating network with supply temperature of 70°C and also the effect to the absorption chiller’s COP. Through the simulation result, it is found out that the lowest possible returning water temperature is 55 °C at COP 0,69 with heat rejection (re-cooling) temperature water at 22 °C. This implies that the desired returning hot water temperature of 47 °C cannot be achieved. The lower returning hot water temperature is preferable since it gives the district heating network benefit in term of less distribution pump work, and energy recovery for the condensation process at central heating plant.