Dissertations / Theses: 'Thermal energy storage in buildings'

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Heier, Johan. "Energy Efficiency through Thermal Energy Storage : Possibilities for the Swedish Building Stock." Licentiate thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-118734.

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The need for heating and cooling in buildings constitutes a considerable part of the total energy use in a country and reducing this need is of outmost importance in order to reach national and international goals for reducing energy use and emissions. One important way of reaching these goals is to increase the proportion of renewable energy used for heating and cooling of buildings. Perhaps the largest obstacle with this is the often occurring mismatch between the availability of renewable energy and the need for heating or cooling, hindering this energy to be used directly. This is one of the problems that can be solved by using thermal energy storage (TES) in order to save the heat or cold from when it is available to when it is needed. This thesis is focusing on the combination of TES techniques and buildings to achieve increased energy efficiency for heating and cooling. Various techniques used for TES as well as the combination of TES in buildings have been investigated and summarized through an extensive literature review. A survey of the Swedish building stock was also performed in order to define building types common in Sweden. Within the scope of this thesis, the survey resulted in the selection of three building types, two single family houses and one office building, out of which the two residential buildings were used in a simulation case study of passive TES with increased thermal mass (both sensible and latent). The second case study presented in the thesis is an evaluation of an existing seasonal borehole storage of solar heat for a residential community. In this case, real measurement data was used in the evaluation and in comparisons with earlier evaluations. The literature reviews showed that using TES opens up potential for reduced energy demand and reduced peak heating and cooling loads as well as possibilities for an increased share of renewable energy to cover the energy demand. By using passive storage through increased thermal mass of a building it is also possible to reduce variations in the indoor temperature and especially reduce excess temperatures during warm periods, which could result in avoiding active cooling in a building that would otherwise need it. The analysis of the combination of TES and building types confirmed that TES has a significant potential for increased energy efficiency in buildings but also highlighted the fact that there is still much research required before some of the technologies can become commercially available. In the simulation case study it was concluded that only a small reduction in heating demand is possible with increased thermal mass, but that the time with indoor temperatures above 24 °C can be reduced by up to 20%. The case study of the borehole storage system showed that although the storage system worked as planned, heat losses in the rest of the system as well as some problems with the system operation resulted in a lower solar fraction than projected. The work presented within this thesis has shown that TES is already used successfully for many building applications (e.g. domestic hot water stores and water tanks for storing solar heat) but that there still is much potential in further use of TES. There are, however, barriers such as a need for more research for some storage technologies as well as storage materials, especially phase change material storage and thermochemical storage.
Behovet av värme och kyla i byggnader utgör en betydande del av ett lands totala energianvändning och att reducera detta behov är av yttersta vikt för att nå nationella samt internationella mål för minskad energianvändning och minskade utsläpp. En viktig väg för att nå dessa mål är att öka andelen förnyelsebar energi för kylning och uppvärmning av byggnader. Det kanske största hindret med detta är det faktum att det ofta råder obalans mellan tillgången på förnyelsebar energi och behovet av värme och kyla, vilket gör att denna energi inte kan utnyttjas direkt. Detta är ett av problemen som kan lösas genom att använda termisk energilagring (TES) för att lagra värme eller kyla från när det finns tillgängligt till dess att det behövs. Denna avhandling fokuserar på kombinationen av TES och byggnader för att nå högre energieffektivitet för uppvärmning och kylning. Olika tekniker för energilagring, samt även kombinationen av TES och byggnader, har undersökts och sammanfattats genom en omfattande litteraturstudie. För att kunna identifiera byggnadstyper vanliga i Sverige gjordes även en kartläggning av det svenska byggnadsbeståndet. Inom ramen för denna avhandling resulterade kartläggningen i valet av tre typbyggnader, två småhus samt en kontorsbyggnad, utav vilka de två småhusen användes i en simuleringsfallstudie av passiv TES genom ökad termisk massa (både sensibel och latent). Den andra fallstudien som presenteras i denna avhandling är en utvärdering av ett existerande borrhålslager för säsongslagring av solvärme i ett bostadsområde. I detta fall användes verkliga mätdata i utvärderingen samt i jämförelser med tidigare utvärderingar. Litteraturstudien visade att användningen av TES öppnar upp möjligheter för minskat energibehov och minskade topplaster för värme och kyla samt även möjligheter till en ökad andel förnyelsebar energi för att täcka energibehovet. Genom att använda passiv lagring genom ökad termisk massa i byggnaden är det även möjligt att minska variationer i inomhustemperaturen och speciellt minska övertemperaturer under varma perioder; något som kan leda till att byggnader som normalt behöver aktiv kylning kan klara sig utan sådan. Analysen av kombinationen av TES och byggnadstyper bekräftade att TES har en betydande potential för ökad energieffektivitet i byggnader, men belyste även det faktum att det fortfarande krävs mycket forskning innan vissa av lagringsteknikerna kan bli kommersiellt tillgängliga. I simuleringsfallstudien drogs slutsatsen att en ökad termisk massa endast kan bidra till en liten minskning i värmebehovet, men att tiden med inomhustemperaturer över 24 °C kan minskas med upp till 20 %. Fallstudien av borrhålslagret visade att även om själva lagringssystemet fungerade som planerat så ledde värmeförluster i resten av systemet, samt vissa problem med driften av systemet, till en lägre solfraktion än beräknat. Arbetet inom denna avhandling har visat att TES redan används med framgång i många byggnadsapplikationer (t.ex. varmvattenberedare eller ackumulatortankar för lagring av solvärme) men att det fortfarande finns en stor potential i en utökad användning av TES. Det finns dock hinder såsom behovet av mer forskning för både vissa lagringstekniker samt lagringsmaterial, i synnerhet för lagring med fasändringsmaterial och termokemisk lagring.

QC 20130225

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Arce, Maldonado Pablo. "Application of passive thermal energy storage in buildings using PCM and awnings." Doctoral thesis, Universitat de Lleida, 2011. http://hdl.handle.net/10803/32001.

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Abedin, Joynal. "Thermal energy storage in residential buildings : a study of the benefits and impacts." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25520.

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Residential space and water heating accounts for around 13% of the greenhouse gas emissions of the UK. Reducing this is essential for meeting the national emission reduction target of 80% by 2050 from the 1990 baseline. One of the strategies adopted for achieving this is focused around large scale shift towards electrical heating. This could lead to unsustainable disparity between the daily peak and off-peak electricity loads, large seasonal variation in electricity demands, and challenges of matching the short and long term supply with the demands. These challenges could impact the security and resilience of UK electricity supply, and needs to be addressed. Rechargeable Thermal Energy Storage (TES) in residential buildings can help overcome these challenges by enabling Heat Demand Shifts (HDS) to off-peak times, reducing the magnitude of the peak loads, and the difference between the peak and off-peak loads. To be effective a wide scale uptake of TES would be needed. For this to happen, the benefits and impacts of TES both for the demand side and the supply side have to be explored, which could vary considerably given the diverse physical, thermal, operational and occupancy characteristics of the UK housing stock. A greater understanding of the potential consequence of TES in buildings is necessary. Such knowledge could enable appropriate policy development to help drive the uptake of TES or to encourage development of alternative solutions. Through dynamic building simulation in TRNSYS, this work generated predictions of the space and water heating energy and power demands, and indoor temperature characteristics of the UK housing stock. Twelve building archetypes were created consisting of: Detached, semi-detached, mid-terrace and flat built forms with thermal insulation corresponding to the 1990 building regulation, and occupied floor areas of 70m2, 90m2 and 150m2. Typical occupancy and operational conditions were used to create twelve Base Case scenarios, and simulations performed for 60 winter days from 2nd January. HDS of 2, 3 and 4 hours from the grid peak time of 17:00 were simulated with sensible TES system sizes of 0.25m3, 0.5m3 and 0.75m3, and water storage temperatures of 75°C and 95°C. Parametric analysis were performed to determine the impacts and benefits of: thermal insulation equivalent to 1980, 1990 (Base Case), 2002 and 2010 building regulation; locations of Gatwick (Base Case) and Aberdeen; heating durations of 6, 9 (Base Case), 12 and 16 hours per day; thermostat settings of 19°C, 21°C (Base Case) and 23°C, and number of occupiers of 1 person and 3 persons (Base Case) per household. Good correlation was observed between the simulated results and published heat energy consumption data for buildings with similar thermal, physical, occupancy and operational conditions. The results allowed occupied space temperatures and overall daily and grid peak time energy consumption to be predicted for the range of building archetypes and parameter values considered, and the TES size necessary for a desired HDS to be determined. The main conclusions drawn include: The overall daily energy consumption predictions varied from 36.8kWh to 159.7kWh. During the critical grid peak time (17:00 to 21:00) the heat consumption varied from 4.2kWh to 58.7kWh, indicating the range of energy demands which could be shifted to off-peak times. On average, semi-detached, mid-terrace, and flat built forms consumed 7.0%, 13.8% and 22.7% less energy for space heating than the detached built form respectively. Thermal insulation changing from the 1990 building regulation level to the 1980 and 2010 building regulation levels could change the mean energy use by +14.7% and -19.6% respectively. A 0.25m3 TES size with 75°C water storage temperature could enable a 2 hour HDS, shifting 4.3kWh to 11.7kWh (mean 8.7kWh) to off peak times, in all 70m2 Base Case archetypes with the 60 day mean thermal comfort of 100%, but with the minimum space temperature occasionally dropping below an 18°C thermal comfort limit. A 0.5m3 TES size and water storage of 95°C could allow a 3 hour HDS, shifting 9.8kWh to 28.2kWh (mean 18.7kWh) to off peak times, in all 90m2 Base Case archetypes without thermal comfort degradation below 18°C. A 0.75m3 TES with a 95°C water temperature could provide 4 hour HDS, shifting 13.9kWh to 47.7kWh (mean 27.2kWh) to off peak times, in all 150m2 Base Case archetypes with 100% mean thermal comfort but with the 60 day minimum temperature occasionally dropping below the 18°C thermal comfort limit in the detached built form. Improving the thermal insulation of the buildings was found to be the best way to improve the effectiveness of HDS with TES, in terms of the demand shift period achievable with minimal thermal comfort impact. A 4 hour HDS with 100% thermal comfort is possible in all 90m2 floor area buildings with a 0.25m3 tank and a water storage temperature of 75°C provided that the thermal insulation is as per 2010 building regulation. Recommendations for further research include: 1) creating larger number of archetype models to reflect the housing stock; 2) using heat pumps as the heat source so that the mean effect on the grid from electric heating loads can be predicted; 3) taking into account the costs associated with taking up HDS with TES, in terms of capital expenses and space requirement for housing the TES system; 4) considering alternative methods of heat storage such as latent heat storage to enhance the storage capacity per unit volume; and 5) incorporating zonal temperature control, for example, only heating rooms that are occupied during the demand shift period, which could ensure better thermal comfort in the occupied space and extend the demand shift period.

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Al-Mosawi, Alaa Liaq Hashem. "Thermal energy storage for building-integrated photovolaic components." Thesis, University of Strathclyde, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549422.

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Henning, Martin, and Endi Tollkuci. "Energy simulation model for commercial buildings Beridarebanan 4, 11 and 77, with ice thermal storage." Thesis, KTH, Energiteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-256068.

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District cooling companies enforce a large penalty based on peak demands, which current cooling methods do not address properly. Building developers are exploring alternatives methods to reduce the said peak demands. The use of Ice Thermal Storage is an nontraditional method within the Scandinavian countries, but has shown to be a method to peak shave as well as load shifting in other regions of the worlds. The goal of the thesis was to "investigate the potential of ice thermal storage for cooling demand and peak shaving for Beridarebanan 4, 11, 77". The energy simulation was accomplished using the building performance simulator software IES VE. As inputs to the simulation, building data from the renovation project and corresponding weather data were used. The resulting simulation model was validated against renovated data with differences of 3,3% and 41,9% for the heating and cooling loads, respectively. The large discrepancy within cooling was determined to be weighted heavily by cooling strategy implemented within the building. When similar cooling strategies were implemented results were consistent with one another. This validation was investigated on a building, zone, and room level to look for consistency. The resulting simulated heating and cooling demands from IES VE were input into a then created ice thermal storage controller within MS Excel. In all, with the stable electrical and district cooling prices, a payback of 12 years was calculated for a 4,5 MWh, 6 hour storage ITS system. Results also show that for a 6 hour storage capacity,the controller exceeded the 1 000 kW price tier 4 hours out of the entire year, making it an ideal storage size. Current Swedish Electrical Market incentivize peak shaving rather than energy saving, accounting for nearly 80% of the yearly savings. The margin for earning more for the energy savings has negative consequences for potentially exceeding the 1 000 kW cooling threshold.

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Mohiuddin, Mohammed Salman. "Membrane-Based Energy Recovery Ventilator Coupled with Thermal Energy Storage Using Phase Change Material for Efficient Building Energy Savings." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404519/.

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This research work is focused on a conceptual combination of membrane-based energy recovery ventilator (ERV) and phase change material (PCM) to provide energy savings in building heating, ventilation & air-conditioning (HVAC) systems. An ERV can recover thermal energy and moisture between the outside fresh air (OFA) entering into the building and the exhaust air (EA) leaving from the building thus reducing the energy consumption of the HVAC system for cooling and heating the spaces inside the building. The membranes were stacked parallel to each other forming adjacent channels in a counter-flow arrangement for OFA and EA streams. Heat and moisture is diffused through the membrane core. Flat-plate encapsulated PCM is arranged in OFA duct upstream/downstream of the ERV thereby allowing for further reduction in temperature by virtue of free cooling. Paraffin-based PCMs with a melting point of 24°C and 31°C is used in two different configurations where the PCM is added either before or after the ERV. Computational fluid dynamics (CFD), and heat and mass transfer modeling is employed using COMSOL Multiphysics v5.3 to perform the heat and mass transfer analysis for the membrane-based ERV and flat-plate PCMs. An 8-story office building was considered to perform building energy simulation using eQUEST v3.65 from Department of Energy (DOE). Based on the heat and mass transfer analysis, it is found that the sensible effectiveness (heat recovery) stood in the range of 65%-97% while the latent effectiveness (moisture recovery) stood at 55%-80%. Also, the highest annual energy savings achieved were 72,700 kWh in electricity consumption and 358.45 MBtu in gas consumption.

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Alkhazaleh, A. "Thermal energy storage and fire safety of building materials." Thesis, University of Bolton, 2018. http://ubir.bolton.ac.uk/1988/.

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Energy storage using organic phase change materials (PCMs) has attracted significant attention in recent years for renewable energy utilization in building materials. PCMs are capable of storing and releasing a large amount of latent heat during their phase transitions. Paraffin (PA), a eutectic mixture (EM) of capric acid (CA) and lauric acid (LA) and butyl stearate (BS) have been selected as PCMs for this work due to their melting temperatures being close to human comfort temperature, 17 - 28 oC. Plaster (PL) as a building material is chosen due to its ease of construction into plaster boards and also because it is a good insulator against heat and sound. The most significant concern when using an organic PCM is its flammability. This research sets out to determine the effect of using PCMs in PL on the product’s flammability, and whether it is possible to use carrier materials and/or flame retardants to reduce their flammability while maintaining the thermal energy storage properties. Three techniques of incorporation of PCMs into PL are used to address this question. The first one is to immerse PL into hot melted PCMs using a vacuum impregnation method. The PCM however, could easily leak to the surface of PL, particularly when the temperature is above the melting temperature of PCM and also their high flammability evaluated using cone calorimetry was a limiting factor to pursuance of this route. The second method is a direct incorporation technique, i.e. adding PCM directly to PL. With this method also the leakage of PCMs was observed and all samples ignited, though the flammability parameters were less intense than those observed when the immersion method was used. To prevent the leakage of PCM and to improve the consistency of organic PCM with building materials, form-stable PCMs composites are used in the third method. Carrier materials, namely nanoclay (NC), diatomaceous earth (DE), expanded perlite (EP), fly ash (FA) and brick dust (BD) were selected to adsorb and retain the PCMs in their pores. SEM (scanning electron microscope) demonstrated that PCMs were uniformly adsorbed in most of the carrier materials. DSC (differential scanning calorimeter) used to measure the thermal properties of PCMs showed that when these form stable composites were added to PL, they acted as PCMs, although the latent heat values were reduced. Thermal gravimetric analysis (TGA) results demonstrates that the PCMs’ decomposition was not affected by the presence of carrier materials or PL. Cone calorimetry showed that the use of carrier materials had minimal effect on the flammability of PCMs. To evaluate the thermal energy storage performance, a small environmental chamber was used, i.e. a small test “room” of PL with dimensions of 100 mm x 100 mm x 100 mm and thickness 10 mm was set up using 6 pieces of PL. The top board of the cubic room contained PCM, and the temperature differences between the surfaces of control PL and modified PL were recorded during heating and cooling of the room. The results from heating and cooling cycles showed that the PCMs and form stable-PCM composites reduced the peak temperature and delayed the time taken to release the stored energy, the values depending on the percentage of PCMs used. To reduce the flammability of PCMs while maintaining their energy storage performance, two approaches have been undertaken: (i) use of expanded graphite (EG) as a flame retardant carrier- material and (ii) use of a liquid flame-retardant, resorcinol bis(diphenyl phosphate) (RDP). The results demonstrated that the flame retardant did not affect the energy storage performance of the PCM. While RDP was not effective on a PA containing PL sample, the flammability of a PL+BS sample was significantly reduced with the addition of EG and RDP.

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Giró, Paloma Jessica. "Characterization of polymers and Microencapsulated Phase Change Materials used for Thermal Energy Storage in buildings." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/346923.

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The use of renewable heat decreases the consumption of fossil resources, although its usage is intermittent and usually does not match the demand. A proper thermal energy storage system design can eliminate this problem by reducing the consumption of non-renewable resources and improving energy efficiency where used. In buildings, thermal energy storage using phase change materials (PCM) is a useful tool to achieve reduction in energy consumption. These can be incorporated into passive or/and active systems. Thus, a proper selection of materials and extensive characterization for its usage in thermal energy storage is critical for new construction systems and for those already constructed. This Thesis is divided in two blocks and presented as a compendium of published articles in scientific journals indexed in Materials, Engineering, and Energy areas. The emphasis is made in the chemical, physical, thermal, mechanical and environmental characterization of PCM, MPCM (microencapsulated phase change materials), and PCS (phase change slurries). The main purpose is to perform an exhaustive characterization of this kind of materials because several scientific studies have highlighted that PCM mixed with construction materials can suffer leakage. Polymeric encapsulation is an alternative for retaining PCM inside building materials, resulting in a system named MPCM. - Macroscopic samples: the nanoindentation tecnique has been used to characterize thermoplastics that, so far, have had few precedents. As mechanical properties of materials are an important criterion for their selection and nanoindentation allows their evaluation, we have studied the hardness and elastic modulus of different polymeric materials through Loubet and Oliver & Pharr methodologies, to discern which is the most suitable concerning the viscoelastic properties. The obtained values by Oliver & Pharr method are based on the unloading curve analysis; in case of Loubet methodology, these values are a function of the penetration depth of the indentation. Also, we have studied the mechanical changes that occur when a polymer that contains a flame retardant is immersed in PCM. It has been observed that using Mg(OH)2 increases rigidity and mechanical strength while reducing the degradation effect and improving the properties against fire. This block contains two scientific published papers. - Microscopic samples: This block is based on MPCM studies. A review of publications related to PCM, MPCM and slurries (PCS) (same shell and different PCM; different shell and same PCM; same shell and same PCM, but different encapsulation ratios) was prepared. Then, the evaluation of the chemical, physical, thermal, mechanical, and environmental properties of different MPCM and PCS samples was performed, concluding that AFM is a useful tool to characterize the stiffness and Young's modulus of MPCM. Because temperature is a key parameter in PCM systems, AFM experiments were carried out at different temperatures, in order to simulate the PCM in solid and/or liquid state. PCS samples were observed using SEM device coupled to a cryogenic system. Besides, environmental properties of PCS have been studied by gas chromatography (VOC’s). In addition, PCS were cycled for the evaluation of the polymeric shell durability after pumping the sample several cycles. Also, the chemical and thermophysical properties before and after pumping the sample were compared. Finally, due to the thermal behavior results of PCS in some performed studies, and depending on the liquid or dried PCS sample, the optimum conditions by means thermogravimetric analysis were evaluated. The second block contains five scientific published articles, one article under review after its first revision, one article finished without being submitted to a journal, and one unfinished research. Finally, the contribution in the state of the art of this PhD Thesis related with thermal energy storage in buildings using PCM, MPCM, and PCS is presented.
Un correcto diseño del sistema de almacenamiento de energía térmica (TES) puede eliminar un uso discontinuo y que habitualmente no coincide con la demanda. El TES mediante materiales de cambio de fase (PCM) en climatización pasiva y activa en edificios es un instrumento útil para alcanzar un descenso del consumo de energía. La Tesis se divide en dos bloques y se presenta como compendio de artículos publicados en revistas científicas indexadas en las áreas de Materiales, Ingeniería, y Energía, haciendo émfasis en la caracterización química, fisica, térmica, mecánica y ambiental de PCM, MPCM (materiales de cambio de fase microencapsulados) y PCS (pulpas con cambio de fase). - Caracterización de diferentes termoplásticos mediante nanoindentación. a través de los métodos de Loubet y Oliver & Pharr. También se han estudiado los cambios mecánicos que se producen cuando un polímero que contiene carga ignifugante en su formulación se sumerge en PCM. Este bloque contiene dos artículos científicos. - Estudio de MPCM. Se ha llevado a cabo una revisión de publicaciones por otros autores. Se han caracterizado con AFM diferentes MPCM y PCS, a diferentes temperaturas. Se han observado muestras de PCS mediante el uso de SEM acoplado a un sistema de crionizado, y se han estudiado las propiedades medioambientales por cromatogyafía de gases. Además, se han ciclado PCS para ver la durabilidad de la pared polimérica después de ciertos ciclos de bombeo. Se han investigado las condiciones óptimas mediante análisis termogravimétrico en PCS. Este segundo bloque contiene cinco artículos científicos publicados, un artículo aceptado en primera revisión, un artículo finalizado sin enviar a revista, y un estudio en investigación. Finalmente, se presentan las conclusiones principales de la contribución de esta Tesis Doctoral en el estado del arte de los PCM, MPCM, y PCS para almacenaje de energía en edificios.

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Malekzadeh, Fatemeh. "Integration of Phase Change Materials in Commercial Buildings for Thermal Regulation and Energy Efficiency." Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/603534.

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One of prospective procedures of absorbing thermal energy and releasing it during the required time is the application of phase change materials known as PCMs in building envelopes. High thermal energy storage (TES) materials has been a technology that effects the energy efficiency of a building by contributing in using onsite resources and reducing cooling or heating loads. Currently, many TES systems are emerging and contributing in building assemblies, however using an appropriate type of TES in a specific building and climate requires an in-depth knowledge of their properties. This research aims to provide a thorough review of a broad range of thermal energy storage technologies including their potential application in buildings. Subsequently, a comparative study and simulation between a basecase and an optimized model by PCM is thoroughly considered to understand the effect of high thermal storage building's shell on energy efficiency and indoor thermal comfort. Specifically this study proposes that the incorporation of PCM into glazing system as a high thermal capacity system will improve windows thermal performance and thermal capacity to varying climatic conditions. The generated results by eQUEST energy modeling software demonstrates approximately 25% reduction in cooling loads during the summer and 10% reduction in heating loads during the winter for optimized office building by PCM in hot arid climate of Arizona. Besides, using PCM in glazing system will reduce heat gain through the windows by conduction phenomenon. The hourly results indicates the effect of PCM as a thermal energy storage system in building envelopes for building's energy efficiency and thermal regulation. However, several problems need to be tackled before LHTES can reliably and practically be applied. We conclude with some suggestions for future work.

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Chen, Bao. "Study of an ettringite-based thermochemical energy storage for buildings." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI056.

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Les besoins en énergie dédiés au chauffage et à l'eau chaude sanitaire dans des bâtiments, caractérisés par des pics de consommation en début et en fin de journée tout comme en hiver, représentent un défi d’importance vis-à-vis de l'utilisation des énergies renouvelables. Une des technologies les plus prometteuses, se présente sous la forme d’un système de stockage d'énergie dit thermochimique (TCES). Ce mode de stockage permet en effet de stocker différents types d'énergie sous la forme d’un potentiel chimique et est caractérisé par une absence de dissipation d'énergie. En tant que matériau de stockage thermochimique récemment étudié, l'ettringite conviendrait ainsi à une utilisation à grande échelle en raison de sa non-toxicité, de son faible coût de production et de sa haute densité énergétique à basse température de fonctionnement. Cette thèse avait pour premier objectif d’étudier les propriétés physico-chimiques de l’ettringite et les mécanismes réactionnels lors des processus d'hydratation (formation d’ettringite) et de déshydratation (formation de méta-ettringite). Les connaissances acquises lors de ces travaux de thèse, vis-à-vis de la cinétique des réactions et des diagrammes thermodynamiques (Déshydratation: Ett30.6 → Ett30 → Met12 → Met6; Hydratation: Met7.4 → Met12 →hydrate de 24H2O→ hydrates supérieurs), permettront ainsi de mieux utiliser l'ettringite pour stocker/déstocker de la chaleur (à différentes conditions isothermes et isobares). Après avoir étudié les propriétés de l'ettringite pure, trois liants cimentaires distincts pouvant être produits industriellement ont été utilisés afin de tester des teneurs en ettringite différentes mais aussi des mélanges de phases hydratées particulières. Les travaux effectués ont permis d’étudier les mécanismes de carbonatation de ces différents matériaux ettringitiques et de déduire plusieurs informations pertinentes quant à leur durabilité dans le cadre d’une utilisation en tant que TCES. Enfin, le matériau cimentaire ettringitique le plus résistant au phénomène de carbonatation a été caractérisé par différentes techniques d’analyse afin de mieux maitriser l’influence des paramètres thermo-physiques sur sa performance énergétique. Ce matériau a ensuite été in-corporé dans un réacteur à lit fixe, sous la forme d’un lit poreux de 56 mm de hauteur composé de granulés de 1 à 2 mm de diamètre. Le processus de chargement/déchargement de l'énergie a été réalisé pour étudier la réversibilité du couple ettringite/méta-ettringite dans diverses conditions expérimentales. Les essais réalisés dans le réacteur ont alors montré qu’une puissance instantanée maximale de 915 W par kg de matière hydratée initiale et une densité de déstockage d'énergie de 176 kWh/m3 pouvaient être obtenues. Ces données seront très utiles pour envisager un futur prototype (à l’échelle 1:1) d’un système de chauffage contenant de l’ettringite et destiné aux bâtiments
The high energy demands for space heating and domestic hot water in buildings, character-ized by peaks in consumption at the beginning and end of the day as well as in winter, repre-sent a major challenge in terms of the use of renewable energies. A system of thermochemical energy storage (TCES), one of the most promising accessible technologies, could store different types of energies as chemical potential without energy dissipation. As a recently studied TCES material, ettringite is suitable for large scale use due to its no-toxicity, low material cost, and high energy density at lowing operating temperature. The first objective of this thesis was to study the physicochemical properties of ettringite and the reaction mechanisms during the hydration (formation of ettringite) and dehydration (formation of meta-ettringite) processes. The knowledge obtained on the reaction kinetics and thermodynamics (Dehydration: Ett30.6 → Ett30 → Met12 → Met6; Hydration: Met7.4 → Met12 →24-hydrate → higher hydrates) allows better use of ettringite for heat storage/release (under different isothermal and isobaric conditions). After having studied the properties of pure ettringite, three different cementitious binders that are industrially producible were used to test different ettringite contents but also mixtures of particular hydrated phases. The work carried out made it possible to study the carbonation mechanisms of these different ettringite materials and to deduce some relevant information as to their durability in terms of their use in TCES. Finally, the ettringite-based material most resistant to the carbonation phenomenon has been characterized by different analysis techniques in order to better control the influence of ther-mo-physical parameters on its energy performance. This material was then incorporated into a fixed bed reactor in the form of a 56 mm high porous bed composed of granules (1–2 mm in diameter). The energy charging / discharging process carried out to study the reversibility of ettringite / meta-ettringite under various experimental conditions. The reactor tests then showed that a maximum instantaneous power of 915 W per kg of initial hydrated material and an energy-releasing density of 176 kWh/m3. These results will be very useful in designing a future prototype (in scale 1:1) containing ettringite materials for a heating system in buildings

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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.

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Grahovac, Milica [Verfasser]. "Modeling and Optimization of Energy Generation and Storage Systems for Thermal Conditioning of Buildings Targeting Conceptual Building Design / Milica Grahovac." Aachen : Shaker, 2013. http://d-nb.info/1051575230/34.

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Gravoille, Pauline. "CASE STUDY OF ACTIVE FREE COOLING WITH THERMAL ENERGY STORAGE TECHNOLOGY." Thesis, KTH, Kraft- och värmeteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-77778.

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May 25, 2011, Reuters’ headline read: "New York State is prepared for summerelectricity demand". The NY operator forecasts for next summer a peak of 33GW, close to therecord ever reached. With soaring cooling demands, the electricity peak load represents a substantialconcern to the energy system. In the goal of peak shaving, research on alternative solutions based onThermal Energy Storage (TES), for both cooling and heating applications, has been largely performed.This thesis addresses thermal comfort applications with use of active free cooling through implementationof latent heat based TES. Active free cooling is based on the use of the freshness of a source, the outsideair for example, to cool down buildings. This work conceptualizes the implementation of TES basedcooling system with use of Phase Change Material in an in-house-built model. The principle of PhaseChange Material, or Latent Heat TES (LHTES), lies on latent energy which is the energy required for thematerial to change phase. In order to properly size this cooling system, a multi-objective optimization isadopted. This optimization, based on minimization of multi-objective functions, led to optimal designconfigurations. In parallel, the electrical consumption of the system and the volume uptake of the systemwere also considered. Through the obtained optimization studies, we identified non-linearinterdependency between the two objective functions: the cost of the system and the acceptable remainingcooling needs. By remaining cooling needs, we mean the cooling needs that the system cannot meet. As amatter of fact, sizing the system according to these cooling needs would imply a very high cost. It wasfound that for a certain amount of remaining cooling needs, the PCM-based cooling system reveals to bean interesting solution compared to conventional air conditioning in terms of electrical consumption andoverall system cost.
Best Master Thesis Award, granted by French Academic Institute
Cold Thermal Energy Storage

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Dahlström, Pontus. "Potential of electrical building heating as thermal energy storage in Sweden." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264344.

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The purpose of this Master thesis is to investigate the potential of using electricity based building heating as thermal energy storage in Sweden and its applications. Building data and statistics along with literature were the basis for data collection and processing. The work was then carried out by selecting a thermal energy storage model to represent different building types that are equipped with electricity based heating systems. This aggregate thermal energy storage model was applied to the Swedish building stock, historical weather data and typical thermal comfort zones. The power and energy capacity of the thermal energy storage were studied and the model was used to evaluate Demand Response (DR) both as Price Based DR and Emergency DR. This thesis gives an approximation of the potential of both power and energy capacity which has not been clearly quantified in previous studies for thermal energy storage in buildings of Sweden. The thesis was carried out for the Department of Energy Technology (EGI) at the Division of Electric Power and Energy Systems (EPE) in collaboration with SWECO as part of the North European Energy Perspectives Project (NEPP).
Syftet med detta examensarbete på Mastersnivå är att utreda potentialen av att använda värmesystem drivna av elektricitet i svenska byggnader som lagring av termisk energi och möjliga tillämpningar. Datainsamlingen och behandlingen baserades på byggnadsdata och statistik tillsammans med lämplig litteratur. Arbetet utfördes sedan genom att välja en modell för lagring av termisk energi för att representera olika byggnadstyper som har värmesystem drivna av elektricitet installerade. Den samlade termiska energilagringsmodellen tillämpades för det svenska byggnadsbeståndet med historiska väderdata och termiska komfortzoner. Effekten och energikapaciteten från den termiska energilagringen studerades och modellen användes sedan för att utvärdera Demand Response (DR) både baserat på elpris och vid nödfall. Examensarbetet uppskattar potentialen av både effekten och energikapaciteten vilket i tidigare studier av lagring av termisk energi i svenska byggnader ej kvantifierats tydligt. Detta examensarbete har utförts för institutionen för energiteknik (EGI) vid institutionen för elkraftteknik (EPE) i samarbete med SWECO inom ramen för North European Energy Perspectives Project (NEPP).

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Xiang, Yetao. "Experimental and computational investigation of building integrated PV thermal air system combined with thermal storage." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/42743/.

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Issues from global warming with increased CO2 emissions have been to a main concern over world. As an example in the UK, the energy demand in the domestic sector has risen by 17% in 2010 compared with that of 1970. Applying renewable energy is widely agreed to be the most effective and promising way to solve the problem where solar energy and photovoltaic technology have been greatly developing from the last century. Photovoltaic combines with Phase Change Material (PV/PCM) system is a hybrid solar system which uses phase change material to reduce the PV temperature and to store energy for other applications. This thesis aims to investigate the performance of a designed building integrated photovoltaic thermal system (BIPVT) with PCM as thermal storage for building applications. The research objectives are to increase the building integrated photovoltaic (BIPV) efficiency by incorporating PCM while utilising the stored heat in PCM for controlling indoor conditions and reduce the total building energy consumption. The research starts with solar energy convection technologies including solar thermal and solar photovoltaic. Then a combined technology named photovoltaic thermal system (PVT) was introduced and discussed. Research work on a different type of PVT using water and air as thermal energy medium was further reviewed and discussed. An analytical approach investigation was presented on a PVT system and the results were used to design the experiment work on PV/PCM configuration. Experiments have been carried out on a prototype PV/PCM air system using monocrystalline photovoltaic modules. Transient simulations of the system performance have also been performed using a commercial computational fluid dynamics (CFD) package based on the finite volume method. The results from simulation were validated by comparing with experimental results. The results indicated that PCM is effective in limiting temperature rise in PV device and the heat from PCM can enhance night ventilation and decrease the building energy consumption to achieve indoor thermal comfort for certain periods of time. An entire building energy simulation with designed PV/PCM air system was also carried out under real weather condition of Nottingham, UK and Shanghai, China. The result also shows a market potential of PV/PCM system and a payback time of 11 years in the UK condition if using electrical heater.

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Psimopoulos, Emmanouil. "Smart control of PV and exhaust air heat pump systems in single-family buildings." Licentiate thesis, Uppsala University, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:du-32581.

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Recently, decentralized household photovoltaic (PV) systems have become more affordable and there is a tendency to decrease subsidies for the PV excess electricity fed into the grid. Therefore, there is growing interest in methods to increase the self-consumption (SC), which is the part of the electricity produced by PV and directly consumed on buildings. It has been found that battery storage is an effective way to achieve this. When there is a heat pump system installed, thermal energy storage using the thermal mass of the building or hot water tanks, can also be used to increase the household self-sufficiency and minimize the final energy use. The main aim of this thesis is to develop operational control strategies for the heating system of a single-family house with an exhaust air heat pump, a photovoltaic system and energy storage. In order to accomplish this a detailed system model was developed in TRNSYS 17, which includes a six-zone building model and the heat pump control. Moreover, these control strategies include short-term weather and price forecast services. Another objective is to evaluate the impact on the benefit of these control strategies in terms of energy use and economic performance for a wide range of boundary conditions (country/climate, electricity prices, occupancy and appliance loads). Results show that the control using a forecast of dynamic electricity price in most locations leads to greater final energy savings than those due to the control using thermal storage for excess PV production. The exception is Sweden, where the result is the opposite. Moreover, the addition of battery storage leads to greater decreases in final energy than the use of the thermal storage (TH mode), which is limited to the thermal mass of the building and small hot water tank of the compact heat pump. As far as the impact of the advanced control (combined use of TH and PRICE) on cost savings is concerned, savings (up to 175 €) are possible in Spain and in Germany. The design of the TH and PRICE mode show low computational complexity that can be easily implemented in existing heat pump controllers. Additionally, the PRICE mode should have no capital and running cost for the end user while the TH mode might require an external electricity meter. Another yet implication with the TH mode is the need to activate the room thermostatic valve.

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Vadiee, Amir. "Energy Management in Large scale Solar Buildings : The Closed Greenhouse Concept." Doctoral thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127911.

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Sustainability has been at the centre of global attention for decades. One of the most challenging areas toward sustainability is the agricultural sector. Here, the commercial greenhouse is one of the most effective cultivation methods with a yield per cultivated area up to 10 times higher than for open land farming. However, this improvement comes with a higher energy demand. Therefore, the significance of energy conservation and management in the commercial greenhouse has been emphasized to enable cost efficient crop production. This Doctoral Thesis presents an assessment of energy pathways for improved greenhouse performance by reducing the direct energy inputs and by conserving energy throughout the system. A reference theoretical model for analyzing the energy performance of a greenhouse has been developed using TRNSYS. This model is verified using real data from a conventional greenhouse in Stockholm (Ulriksdal). With this, a number of energy saving opportunities (e.g. double glazing) were assessed one by one with regards to the impact on the annual heating, cooling and electricity demand. Later, a multidimensional energy saving method, the “Closed Greenhouse”, was introduced. The closed greenhouse is an innovative concept with a combination of many energy saving opportunities. In the ideal closed greenhouse configuration, there are no ventilation windows, and the excess heat, in both sensible and latent forms, needs to be stored using a seasonal thermal energy storage. A short term (daily) storage can be used to eliminate the daily mismatch in the heating and cooling demand as well as handling the hourly fluctuations in the demand. The key conclusion form this work is that the innovative concept “closed greenhouse” can be cost-effective, independent of fossil fuel and technically feasible regardless of climate condition. For the Nordic climate case of Sweden, more than 800 GWh can be saved annually, by converting all conventional greenhouses into this concept. Climate change mitigation will follow, as a key impact towards sustainability. In more detail, the results show that the annual heating demand in an ideal closed greenhouse can be reduced to 60 kWhm-2 as compared to 300 kWhm-2 in the conventional greenhouse. However, by considering semi-closed or partly closed greenhouse concepts, practical implementation appears advantageous. The required external energy input for heating purpose can still be reduced by 25% to 75% depending on the fraction of closed area. The payback period time for the investment in a closed greenhouse varies between 5 and 8 years depending on the thermal energy storage design conditions. Thus, the closed greenhouse concept has the potential to be cost effective. Following these results, energy management pathways have been examined based on the proposed thermo-economic assessment. From this, it is clear that the main differences between the suggested scenarios are the type of energy source, as well as the cooling and dehumidification strategies judged feasible, and that these are very much dependent on the climatic conditions Finally, by proposing the “solar blind” concept as an active system, the surplus solar radiation can be absorbed by PVT panels and stored in thermal energy storage for supplying a portion of the greenhouse heating demand. In this concept, the annual external energy input for heating purpose in a commercial closed greenhouse with solar blind is reduced by 80%, down to 62 kWhm-2 (per unit of greenhouse area), as compared to a conventional configuration. Also the annual total useful heat gain and electricity generation, per unit of greenhouse area, by the solar blind in this concept is around 20 kWhm-2 and 80 kWhm-2, respectively. The generated electricity can be used for supplying the greenhouse power demand for artificial lighting and other devices. Typically, the electricity demand for a commercial greenhouse is about 170 kWhm-2. Here, the effect of “shading” on the crop yield is not considered, and would have to be carefully assessed in each case.
Hållbarhet har legat i fokus under decennier. En av de mest utmanande områdena är jordbrukssektorn, där. kommersiella växthus är ett av de mest effektiva odlingsalternativen med en avkastning per odlad yta upp till 10 gånger högre än för jordbruk på friland. Dock kommer denna förbättring med ett högre energibehov. Därför är energieffektivisering i kommersiella växthus viktig för att möjliggöra kostnadseffektiv odling. Denna doktorsavhandling presenterar en utvärdering av olika energiscenarios för förbättring av växthusens prestanda genom att minska extern energitillförsel och spara energi genom i systemet som helhet. För studien har en teoretisk modell för analys av energiprestanda i ett växthus utvecklats med hjälp av TRNSYS. Denna modell har verifierats med hjälp av verkliga data från ett konventionellt växthus i Stockholm (Ulriksdal). Med denna modell har ett antal energibesparingsåtgärder (som dubbelglas) bedömts med hänsyn till de totala värme-, kyl-och elbehoven. En flerdimensionell metod för energibesparing, det s.k. "slutna växthuset", introduceras. Det slutna växthuset är ett innovativt koncept som är en kombination av flera energibesparingsmöjligheter. I den ideala slutna växthuskonfigurationen finns det inga ventilationsfönster och värmeöverskott, både sensibel och latent, lagras i ett energilager för senare användning. Daglig lagring kan användas för att eliminera den dagliga obalansen i värme-och kylbehovet. Ett säsongslager introduceras för att möjliggöra användandet av sommarvärme för uppvärmning vintertid. Den viktigaste slutsatsen från detta arbete är att ett sådant innovativt koncept, det "slutna växthuset" kan vara kostnadseffektiv, oberoende av fossila bränslen och tekniskt genomförbart oavsett klimatförhållanden. För det svenska klimatet kan mer än 800 GWh sparas årligen, genom att konvertera alla vanliga växthus till detta koncept. Det årliga värmebehovet i ett idealiskt slutet växthus kan reduceras till 60 kWhm-2 jämfört med 300 kWhm-2 i ett konventionellt växthus. Energibesparingen kommer även att minska miljöpåverkan. Även ett delvis slutet växthus, där en del av ytan är slutet, eller där viss kontrollerad ventilation medges, minskar energibehovet samtidigt som praktiska fördelar har kunnat påvisas. Ett delvis slutet växthus kan minska energibehovet för uppvärmning med mellan 25% och 75% beroende på andelen sluten yta. En framräknad återbetalningstid för investeringen i ett slutet växthus varierar mellan 5 och 8 år beroende på design av energilagringssystemet. Sålunda har det slutna växthuskonceptet potential att vara kostnadseffektiv. Mot bakgrund av dessa lovande resultat har sedan scenarios för energy management analyserats med hänsyn till termo-ekonomiska faktorer. Från detta är det tydligt att de viktigaste skillnaderna mellan de föreslagna scenarierna är den typ av energikälla, samt kyl- och avfuktningsstrategier som används, och dessa val är mycket beroende av klimatförhållandena. Slutligen, föreslås ett nytt koncept, en s.k. "solpersienn", vilket är ett aktivt system där överskottet av solstrålningen absorberas av PVT-paneler och lagras i termiskenergilager för att tillföra en del av växthuseffekten värmebehov. I detta koncept minskar den årliga externa energitillförseln för uppvärmning i ett slutet växthus med 80%, ner till 62 kWhm-2. Den totala värme- och elproduktionen, med konceptet "solpersienn" blir cirka 20 kWhm-2 respektive 80 kWhm-2. Elproduktion kan användas för artificiell belysning och annan elektrisk utrustning i växthuset.

QC 20130910

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Aldubyan, Mohammad Hasan. "Thermo-Economic Study of Hybrid Photovoltaic-Thermal (PVT) Solar Collectors Combined with Borehole Thermal Energy Storage Systems." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1493243575479443.

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Alfadda, Abdullah Ibrahim A. "Strategies for Managing Cool Thermal Energy Storage with Day-ahead PV and Building Load Forecasting at a District Level." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/93509.

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In hot climate areas, the electrical load in a building spikes, but not by the same amount daily due to various conditions. In order to cover the hottest day of the year, large cooling systems are installed, but are not fully utilized during all hot summer days. As a result, the investments in these cooling systems cannot be fully justified. A solution for more optimal use of the building cooling system is presented in this dissertation using Cool Thermal Energy Storage (CTES) deployed at a district level. Such CTES systems are charged overnight and the cool charge is dispatched as cool air during the day. The integration of the CTES helps to downsize the otherwise large cooling systems designed for the hottest day of the year. This reduces the capital costs of installing large cooling systems. However, one important question remains - how much of the CTES should be charged during the night, such that the cooling load for the next day is fully met and at the same time the CTES charge is fully utilized during the day. The solution presented in this dissertation integrated the CTES with Photovoltaics (PV) power forecasting and building load forecasting at a district level for a more optimal charge/discharge management. A district comprises several buildings of different load profiles, all connected to the same cooling system with central CTES. The use of forecasting for both the PV and the building cooling load allows the building operator to more accurately determine how much of the CTES should be charged during the night, such that the cooling system and CTES can meet the cooling demand for the next day. Using this approach, the CTES would be optimally sized, and utilized more efficiently during the day. At the same time, peak load savings are achieved, thus benefiting an electric utility company. The district presented in this dissertation comprises PV panels and three types of buildings – a mosque, a clinic and an office building. In order to have a good estimation for the required CTES charge for the next day, reliable forecasts for the PV panel outputs and the electrical load of the three buildings are required. In the model developed for the current work, dust was introduced as a new input feature in all of the forecasting models to improve the models' accuracy. Dust levels play an important role in PV output forecasts in areas with high and variable dust values. The overall solution used both the PV panel forecasts and the building load forecasts to estimate the CTES charge for the next day. The presented method was tested against the baseline method with no forecasting system. Multiple scenarios were conducted with different cooling system sizes and different CTES capacities. Research findings indicated that the presented method utilized the CTES charge more efficiently than the baseline method. This led to more savings in the energy consumption at the district level.
Doctor of Philosophy
In hot weather areas around the world, the electrical load in a building spikes because of the cooling load, but not by the same amount daily due to various conditions. In order to meet the demand of the hottest day of the year, large cooling systems are installed. However, these large systems are not fully utilized during all hot summer days. As a result, the investments in these cooling systems cannot be fully justified. A solution for more optimal use of the building cooling system is presented in this dissertation using Cool Thermal Energy Storage (CTES) deployed at a district level. Such CTES systems are charged overnight and the cool charge is dispatched as cool air during the day. The integration of the CTES helps to downsize the otherwise large cooling systems designed for the hottest day of the year. This reduces the capital costs of installing large cooling systems. However, one important question remains - how much of the CTES should be charged during the night, such that the cooling load for the next day is fully met and at the same time the CTES charge is fully utilized during the day. The solution presented in this dissertation integrated the CTES with Photovoltaics (PV) power forecasting and building load forecasting at a district level for a more optimal charge/discharge management. A district comprises several buildings all connected to the same cooling system with central CTES. The use of the forecasting for both the PV and the building cooling load allows the building operator to more accurately determine how much of the CTES should be charged during the night, such that the cooling system and CTES can meet the cooling demand for the next day. Using this approach, the CTES would be optimally sized and utilized more efficiently. At the same time, peak load is lowered, thus benefiting an electric utility company.

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Simmons, Cody Ryan. "Proactive Energy Optimization in Residential Buildings with Weather and Market Forecasts." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7594.

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This work explores the development of a home energy management system (HEMS) that uses weather and market forecasts to optimize the usage of home appliances and to manage battery usage and solar power production. A Moving Horizon Estimation (MHE) application is used to find the unknown home model parameters. These parameters are then updated in a Model Predictive Controller (MPC) which optimizes and balances competing comfort and economic objectives. Combining MHE and MPC applications alleviates model complexity commonly seen in HEMS by using a lumped parameter model that is adapted to fit a high-fidelity model. HVAC on/off behaviors are simulated by using Mathematical Program with Complementary Constraints (MPCCs) and solved in near real-time with a nonlinear solver. Removing HVAC on/off as a discrete variable decreases potential solutions and consequently reduces solve time and increases the probability of reaching a more optimal solution. The results of this work indicate that energy management optimization significantly decreases energy costs and balances energy usage more effectively throughout the day compared to a home with regular temperature control. A case study for Phoenix, Arizona shows an energy reduction of 21% and a cost reduction of 40%. Homes using this home energy optimization will contribute less to the grid peak load and therefore, improve grid stability and reduce the amplitude of load following cycles for utilities. This case study combines renewable energy, energy storage, forecasts, cooling system, variable rate electricity plan and a multi-objective function allowing for a complete home energy optimization assessment. There remain several challenges, including improved forecast models, improved computational performance to allow the algorithms to run in real-time, and mixed empirical / first principles machine learning methods to guide the model structure.

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Campbell, Kevin Ryan. "Phase Change Materials as a Thermal Storage Device for Passive Houses." PDXScholar, 2011. http://pdxscholar.library.pdx.edu/open_access_etds/201.

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This study describes a simulation-based approach for informing the incorporation of Phase Change Materials (PCMs) in buildings designed to the "Passive House" standard. PCMs provide a minimally invasive method of adding thermal mass to a building, thus mitigating overheating events. Phase change transition temperature, quantity, and location of PCM were all considered while incrementally adding PCM to Passive House simulation models in multiple climate zones across the United States. Whole building energy simulations were performed using EnergyPlus from the US Department of Energy. A prototypical Passive House with a 1500 Watt electric heater and no mechanical cooling was modeled. The effectiveness of the PCM was determined by comparing the zone-hours and zone-degree-hours outside the ASHRAE defined comfort zone for all PCM cases against a control simulation without PCM. Results show that adding PCM to Passive Houses can significantly increase thermal comfort so long as the house is in a dry or marine climate. The addition of PCM in moist climates will not significantly increase occupant comfort because the majority of discomfort in these climates arises due to latent load. For dry or marine climates, PCM has the most significant impact in climates with lower cooling degree-days, reducing by 93% the number of zone-hours outside of thermal comfort and by 98% the number of zone-degree-hours uncomfortable in Portland, Oregon. However, the application of PCM is not as well suited for very hot climates because the PCM becomes overcharged. Only single digit reductions in discomfort were realized when modeling PCM in a Passive House in Phoenix, Arizona. It was found that regardless of the climate PCM should be placed in the top floor, focusing on zones with large southern glazing areas. Also, selecting PCM with a melt temperature of 25°C resulted in the most significant increases in thermal comfort for the majority of climates studied.

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Barreneche, Güerisoli Camila. "Development and characterization of new materials incorporating phase change materials (PCM) for thermal energy storage (TES) applications in buildings." Doctoral thesis, Universitat de Lleida, 2013. http://hdl.handle.net/10803/123749.

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Actualment, la demanda d'energia per satisfer el confort tèrmic en edificació és un dels majors reptes per a les administracions. Per tant, l'eficiència dels diferents sistemes d'emmagatzematge d'energia s està investigant intensament per la comunitat científica. Una alternativa viable és l'ús de materials de canvi de fase (PCM). Les parafines han estat molt utilitzades com PCM per la seva alta capacitat d'emmagatzematge de calor (al voltant de 100-130 kJ·kg-1) i la seva baixa temperatura de fusió la qual és molt estable. A més, el consum d'energia i les oscil·lacions de la temperatura internes d'edificis es poden reduir quan un PCM s'incorpora en evolvents. L'objectiu principal d'aquesta tesi és el desenvolupament de nous materials que continguin PCM basant-se en l'estudi del procés per obtenir la correcta introducció del PCM dins el material. A més, les propietats termofísiques d'aquests nous materials s'han de conèixer i per tant caracteritzar a nivell de laboratori. Aquesta tesi doctoral se centra en els treballs publicats en revistes científiques amb alt factor d'impacte indexats al camp de l Energia els quals reflecteixen treball realitzat. D'altra banda, aquesta tesi conté una revisió de l'estat de l'art destacant els requisits per a un PCM i llista tots els tipus de PCM disponibles al mercat i utilitzats en investigació. D'altra banda, un nou concepte de material compost que incorpora PCM ha estat desenvolupat en aquesta tesi. Aquest compost té la matriu polimèrica, i inclou un residu del procés de reciclatge de l acer. D'aquesta manera s'obtenen làmines denses que es poden modelar. La fabricació d'aquest material podria considerar-se un mètode per a la reutilització d'aquest residu. D'altra banda, aquest tipus de residus conté òxids de metalls pesants que augmenten les propietats d'aïllant acústic de la làmina aconseguint millorar el resultat final de la solució constructiva. A més, el comportament termofísico dels materials compostos utilitzats en edificis és difícil de caracteritzar i l'anàlisi tèrmica dels PCM és un pas necessari per al disseny dels mateixos. Les dues primeres caracteritzacions termofísiques estudiades en aquesta tesi es van realitzar mitjançant corbes calorimètriques que és una de les tècniques més potents disponibles actualment. tres estudis més van ser van realitzar amb dispositius desenvolupats per diferents grups d'investigació a Espanya per tal de mesurar les propietats termofísiques dels materials compostos o materials multicapa que incorporen PCM.
Hoy en día, la demanda de energía para satisfacer el confort térmico en edificación es uno de los mayores desafíos para las administraciones. Por lo tanto, la eficiencia de los diferentes sistemas de almacenamiento de energía está siendo intensamente investigado por la comunidad científica. Una alternativa viable es el uso de materiales de cambio de fase (PCM). La parafina ha sido muy usada como PCM debido a su alta capacidad de almacenamiento de calor (alrededor de 100-130 kJ·kg-1) y a su baja temperatura de fusión la cual es muy estable. Además, el consumo de energía y las oscilaciones de la temperatura internas se pueden reducir cuando un PCM se incorpora en envolventes de edificios. El objetivo principal de esta tesis es el desarrollo de nuevos materiales que contengan PCM basándose en el estudio del proceso para obtener la correcta introducción del PCM. Además, las propiedades termofísicas de estos nuevos materiales se debe conocer y por tanto caracterizar a nivel de laboratorio. Esta tesis doctoral se centra en los trabajos publicados en revistas científicas con alto factor de impacto indexados en el campo de Energía los cuales reflejan el trabajo realizado. Por otra parte, esta tesis contiene una revisión del estado del arte destacando los requisitos para un PCM y lista todos los tipos de PCM comercializados y utilizados en investigación. Por otra parte, un nuevo concepto de material compuesto que incorpora PCM ha sido desarrollado en esta tesis. Este compuesto tiene la matriz polimérica, e incluye un residuo del proceso de reciclaje de acero. De este modo se obtienen láminas densas moldeables. La fabricación de este material podría considerarse un método para la reutilización de este residuo. Por otra parte, este tipo de residuos contiene óxidos de metales pesados que aumentan las propiedades de aislante acústico de la lámina consiguiendo mejorar el resultado final de la solución constructiva. Además, el comportamiento termofísico de los materiales compuestos utilizados en edificios es difícil de caracterizar y el análisis térmico de los PCM es un paso necesario para el diseño de los mismos. Las dos primeras caracterizaciones termofísicas estudiadas en esta tesis se realizaron mediante calorimetría diferencial de barrido que es una de las técnicas más potentes disponibles actualmente. tres estudios más fueron realizaron con dispositivos desarrollados por diferentes grupos de investigación en España con el fin de medir las propiedades termofísicas de los materiales compuestos o materiales multicapa que incorporan PCM.
Nowadays, energy demand to satisfy thermal comfort in buildings is one of the major challenges for governments and administrations. Therefore, energy storage system efficiency is being studied by the international scientific community. A feasible alternative is the use of phase change materials (PCM). Paraffin waxes have been used as PCM because of their high heat storage capacity (around 100-130 kJ·kg"1) and their low and stable melting temperature. Furthermore, the energy consumption and indoor oscillations temperature may be reduced when PCM is incorporated in building envelopes and the thermal inertia increment when PCM is combined with thermal insulation was widely studied. The main objective of this thesis is the development of new materials containing PCM based on the study of process to get the correct PCM introduction. In addition, thermophysical properties of these new materials must be characterized. In order to perform the characterization, it was used several developed devices. This PhD thesis is based on papers published in scientific journals with high impact factor in the Energy field and one patent that reflect the work performed. This thesis contains a review of the state of the art highlighting the requirements order to a certain PCM and lists and sorts all PCM available in the market and used in research. On the other hand, a new concept of composite material incorporating PCM is developed in this thesis. This composite has polymeric matrix and includes one waste from the steel recycling process obtaining mouldable dense sheets. The manufacture of this material is considered a way to reuse the waste. Furthermore, this waste contains heavy metals oxides which add acoustic insulation properties to the final constructive system. One patent and two papers are the main result. Moreover, thermophysical behaviour of composite materials used in buildings envelopes is difficult to characterize. In addition, PCM thermal analysis is a necessary step of building design as well as it will be a key point in the final thermal results of the envelope. The first two thermophysical characterizations studied in this thesis were performed using differential scanning calorimetry which is one of the most powerful techniques. Three more studies were performed using devices developed by different research groups in Spain in order to measure thermophysical properties of composite materials or multilayered materials incorporating PCM.

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Wong, Kin-chuen, and 黃健全. "Optimization of building cooling system based on genetic algorithms and thermal energy storage." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B45701416.

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Elhashmi, Rodwan. "Comprehensive Study Toward Energy Opportunity for Buildings Considering Potentials for Using Geothermal and Predicting Chiller Demand." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1589332482268134.

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Saffari, Tabalvandani Mohammad. "Simulation-based optimization of thermal energy storage (TES) materials for building and industry applications." Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/459304.

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Una quantitat substancial d'energia s'utilitza en els sectors de l'edificació i de la indústria per als propòsits de la calefacció i de la refrigeració. Els materials d'emmagatzematge d'energia tèrmica (TES) poden oferir importants beneficis energètics i econòmics als edificis residencials, comercials i industrials. Els materials de TES tenen el potencial per reduir les demandes de refredament i de l'electricitat màxima en sectors de l'edificació i de la indústria; però, per tal d'implementar adequadament aquesta tecnologia per maximitzar els beneficis econòmics, es necessiten tècniques de simulació i optimització numèrica. La important contribució original que emergeix de la present tesi és l'ús de mètodes de simulació numèrica i optimització per avançar l'aplicació de la tecnologia TES en els sectors residencials i industrials. Per a això, es presentarà una revisió pel que fa a l'ús d'eines de simulació d'energia per al desenvolupament d'edificis per analitzar passivament els materials realçats amb TES.
Una cantidad substancial de energía se utiliza en los sectores de la edificación y de la industria para los propósitos de la calefacción y de la refrigeración. Los materiales de almacenamiento de energía térmica (TES) pueden ofrecer importantes beneficios energéticos y económicos a los edificios residenciales, comerciales e industriales. Los materiales de TES tienen el potencial para reducir las demandas de enfriamiento y de la electricidad máxima en sectores de la edificación y de la industria; sin embargo, con el fin de implementar adecuadamente esta tecnología para maximizar los beneficios económicos, se necesitan técnicas de simulación y optimización numérica. La importante contribución original que emerge de la presente tesis es el uso de métodos de simulación numérica y optimización para avanzar la aplicación de la tecnología TES en los sectores residenciales e industriales.
A substantial amount of energy is used in building and industry sectors for heating and cooling purposes. Thermal energy storage (TES) materials can offer important short-term and long-term energy, economic, and comfort benefits to residential, commercial, and industrial buildings. TES materials have the potential to reduce the cooling and peak electricity demands in building and industry sectors, however, in order to properly implement this technology to maximize the economic benefits, numerical simulation and optimization techniques are necessary. The significant original contribution emerges from the present thesis is the use of numerical simulation and optimization methods to advance the application of TES technology in the industrial and building sector. To achieve this, a review will be presented regarding the use of whole-building energy simulation tools to analyse buildings passively enhanced with TES materials.

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Zhu, Xuanlin. "Exploring the possibility of applying seasonal thermal energy storage in south-west of China." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-17077.

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Buildings energy consumption is rising continuously with massive urbanization progress, which then results in high greenhouse gas emission. A standing example is the urbanization process going on in the south-west part of China. Much has been discussed for improving building energy performance. However, to take another point of view, renewable energy source for buildings is a solution worth considering, for instance STES, which gains thermal energy from the sun, delivers it to buildings for space heating and hot tap water, also restores the solar energy in hot seasons in the storage system for the need of cold season.The aim of this paper is to couple the technology of STES with practical situation, explore the possibility of applying STES in south-west of China. This thesis work takes an estimation approach to weigh the possibility. The building project studied in this thesis is a campus project in the city of Guiyang, one of four major cities in the region of south-west China.Case study involves existing STES projects in Munich Germany and Anneberg Sweden, the performance evaluation of the Anneberg project is later to serve as an example in system gain & losses proportion, to guide the estimation work of the campus project.The estimation conclusion is drawn based on a cross-sectional analysis method, take the technology of STES, the practiced STES project and building projects in China as three loops visually, and observe how much they overlap each other. Behind the visual illustration, the overlapping is assessed with several factors, for instance possibility of storage system at location, possible STES performance and solar irradiation condition at site location etc. If most of these factors are checked to be “Ok” or “Good”, then the overlapping area is considered “large” enough, and therefore suggests a decent chance to implement STES system in the south-west China.A solar gain and sunlight simulation from a new police station energy consumption report assists in calculating the possible solar gain for the campus project, as the very close distance between these two sites (30 km) promises them the very similar solar irradiation condition. While the energy consumption of the studied campus project offers the energy demand for space heating and hot tap water in the need of 19,000 students, which is to be evaluated as the task of the STES system in the estimation work. Both building project reports are filed by GARDI (Architecture design research institution of Guizhou).Some key factors have been calculated and estimated, the heat demand of the studied campus project in Guiyang is 5,558 MWh/year, and the possible solar gain of this campus complexity is 4,900 MWh/year based on the gain & losses proportion of the Anneberg project evaluation. Due to the very different climate condition of Guiyang and Anneberg, as well as other uncertain factors such as effective roof area, solar collector efficiency, a sensitivity analysis evaluated the result with different parameters in changes of percentage. Final results in the changes of effective roof area at 80% and 85 %, borehole losses at 50% and 45%, available solar gain at 38%, STES system is shown to be capable of providing sufficient heat to buildings. If the heating demand and hot tap water, in the case of the campus project alone are all covered by STES system, there will be a reduction in CO2 emission of 5,368 tons/year.Cross-sectional analysis concludes four out of eight factors checked as “Good” and two as “Ok”, other two as “Unsure”. Other three cities (Chengdu, Kunming, and Chongqing) are brought to comparison later regarding climate condition. Besides Guiyang, two out of three are evaluated to have potential of STES implementation according to their sun hours, annual average temperature etc. STES system is estimated to be possible for implementation in south-west of China as the conclusion.

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Clauss, John. "Feasibility study for upgrading the current heat distribution network of an existing building complex to a Smart Thermal Grid." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173741.

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A feasibility study on upgrading an existing heat distribution network to a low-temperature distribution grid has been carried out during this project. The integration of a solar thermal system combined with a borehole thermal energy storage (BTES) for covering the space heating demand of the buildings as well as the application of CO2 heat pumps and water storage tanks for domestic hot water (DHW) production were investigated in order to apply more renewable energy sources. The energy analysis included several measures, such as modeling the energy demand of the buildings, finding a reasonable number of solar collectors to be installed and dimensioning a ground source heat pump (with the use of CoolPack and Engineering Equation Solver EES) and a geothermal storage (Earth Energy Designer Software EED) as well as CO2 heat pumps (CoolPack/EES). An economic analysis of all proposed measures has been carried out based on the Net Present Value (NPV) and Net Present Value Quotient (NPVQ). Initial costs, annual costs, annual savings as well as the payback time of the energy systems have been calculated. It is found that it is not feasible to invest in the proposed energy system for space heating because the payback time (28 years) of the system is longer than the lifetime of the solar thermal system. Furthermore, the solar gain from the solar collectors is not sufficient for recovering the ground temperature of the BTES with solar energy only which is why external sources would be needed for supplying the remaining energy needed to recover the ground temperature. Results show that an integration of CO2 heat pumps and water storage tanks for DHW production is very promising as the payback time for the investigated system is only 4 years which is why this part should be investigated further.

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Caliguri, Ryan P. "Comparison of Sensible Water Cooling, Ice building, and Phase Change Material in Thermal Energy Storage Tank Charging: Analytical Models and Experimental Data." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1627666292483648.

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Kamal, Rajeev. "Optimization and Performance Study of Select Heating Ventilation and Air Conditioning Technologies for Commercial Buildings." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6656.

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Buildings contribute a significant part to the electricity demand profile and peak demand for the electrical utilities. The addition of renewable energy generation adds additional variability and uncertainty to the power system. Demand side management in the buildings can help improve the demand profile for the utilities by shifting some of the demand from peak to off-peak times. Heating, ventilation and air-conditioning contribute around 45% to the overall demand of a building. This research studies two strategies for reducing the peak as well as shifting some demand from peak to off-peak periods in commercial buildings: 1. Use of gas heat pumps in place of electric heat pumps, and 2. Shifting demand for air conditioning from peak to off-peak by thermal energy storage in chilled water and ice. The first part of this study evaluates the field performance of gas engine-driven heat pumps (GEHP) tested in a commercial building in Florida. Four GEHP units of 8 Tons of Refrigeration (TR) capacity each providing air-conditioning to seven thermal zones in a commercial building, were instrumented for measuring their performance. The operation of these GEHPs was recorded for ten months, analyzed and compared with prior results reported in the literature. The instantaneous COPunit of these systems varied from 0.1 to 1.4 during typical summer week operation. The COP was low because the gas engines for the heat pumps were being used for loads that were much lower than design capacity which resulted in much lower efficiencies than expected. The performance of equivalent electric heat pump was simulated from a building energy model developed to mimic the measured building loads. An economic comparison of GEHPs and conventional electrical heat pumps was done based on the measured and simulated results. The average performance of the GEHP units was estimated to lie between those of EER-9.2 and EER-11.8 systems. The performance of GEHP systems suffers due to lower efficiency at part load operation. The study highlighted the need for optimum system sizing for GEHP/HVAC systems to meet the building load to obtain better performance in buildings. The second part of this study focusses on using chilled water or ice as thermal energy storage for shifting the air conditioning load from peak to off-peak in a commercial building. Thermal energy storage can play a very important role in providing demand-side management for diversifying the utility demand from buildings. Model of a large commercial office building is developed with thermal storage for cooling for peak power shifting. Three variations of the model were developed and analyzed for their performance with 1) ice storage, 2) chilled water storage with mixed storage tank and 3) chilled water storage with stratified tank, using EnergyPlus 8.5 software developed by the US Department of Energy. Operation strategy with tactical control to incorporate peak power schedule was developed using energy management system (EMS). The modeled HVAC system was optimized for minimum cost with the optimal storage capacity and chiller size using JEPlus. Based on the simulation, an optimal storage capacity of 40-45 GJ was estimated for the large office building model along with 40% smaller chiller capacity resulting in higher chiller part-load performance. Additionally, the auxiliary system like pump and condenser were also optimized to smaller capacities and thus resulting in less power demand during operation. The overall annual saving potential was found in the range of 7-10% for cooling electricity use resulting in 10-17% reduction in costs to the consumer. A possible annual peak shifting of 25-78% was found from the simulation results after comparing with the reference models. Adopting TES in commercial buildings and achieving 25% peak shifting could result in a reduction in peak summer demand of 1398 MW in Tampa.

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Al-Hadban, Yehya. "Demand-side management in office buildings in Kuwait through an ice-storage assisted HVAC system with model predictive control." Thesis, Cranfield University, 2005. http://hdl.handle.net/1826/3885.

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Examining methods for controlling the electricity demand in Kuwait was the main objective and motivation of this researchp roject. The extensiveu se of air-conditioning for indoor cooling in office and large commercial buildings in Kuwait and the Gulf States represents a major part of the power and electricity consumption in such countries. The rising electricity generation cost and growing rates of consumption continuously demand the construction new power plants. Devising and enforcing Demand-SideM anagemen(t DSM) in the form of energye fficient operations trategies was the response of this research project to provide a means to rectify this situation using the demand-side management technique known as demand levelling or load shifting. State of the art demand-sidem anagementte chniquesh ave been examined through the developmenot f a model basedp redictive control optimisations trategyf or an integrateda ndm odulara pproachto the provisiono f ice thermals torage. To evaluate the potential of ice-storage assisted air-conditioning systems in flattening the demand curve at peak times during the summer months in Kuwait, a model of a Heating, Ventilation, and Air-conditioning (HVAC) plant was developed in Matlab. The model engaged the use of model based predictive control (MPQ as an optimisation tool for the plant as a whole. The model with MPC was developed to chose and decide on which control strategy to operate the integrated ice-storage HVAC plant. The model succeeded in optimising the operation of the plant and introduced encouraging improvement of the performance of the system as a whole. The concept of the modular ice-storage system was introduced through a control zoning strategy based on zonal orientation. It is believed that such strategy could lead to the modularisation of ice-storage systems. Additionally, the model was examined and tested in relation to load flattening and demonstrated promising enhancement in the shape of the load curve and demonstrated flattened demand curves through the employed strategy. When compared with measured data from existing buildings, the model showed potential for the techniques utilised to improve the load factor for office buildings.

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Grahovac, Milica Verfasser], Thomas [Akademischer Betreuer] Hamacher, Ulrich [Akademischer Betreuer] Wagner, and Gerhard [Akademischer Betreuer] [Hausladen. "Modeling and Optimization of Energy Generation and Storage Systems for Thermal Conditioning of Buildings Targeting Conceptual Building Design / Milica Grahovac. Gutachter: Ulrich Wagner ; Gerhard Hausladen ; Thomas Hamacher. Betreuer: Thomas Hamacher." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1031512624/34.

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Baniasadi, Ali. "Application of heat pumps and thermal storage systems for improved control and performance of microgrids." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2020. https://ro.ecu.edu.au/theses/2316.

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The high penetration of renewable energy sources (RES), in particular, the rooftop photovoltaic (PV) systems in power systems, causes rapid ramps in power generation to supply load during peak-load periods. Residential and commercial buildings have considerable potential for providing load exibility by exploiting energy-e_cient devices like ground source heat pump (GSHP). The proper integration of PV systems with the GSHP could reduce power demand from demand-side. This research provides a practical attempt to integrate PV systems and GSHPs e_ectively into buildings and the grid. The multi-directional approach in this work requires an optimal control strategy to reduce energy cost and provide an opportunity for power trade-o_ or feed-in in the electricity market. In this study, some optimal control models are developed to overcome both the operational and technical constraints of demand-side management (DSM) and for optimum integration of RES. This research focuses on the development of an optimal real-time thermal energy management system for smart homes to respond to DR for peak-load shifting. The intention is to manage the operation of a GSHP to produce the desired amount of thermal energy by controlling the volume and temperature of the stored water in the thermal energy storage (TES) while optimising the operation of the heat distributors to control indoor temperature. This thesis proposes a new framework for optimal sizing design and real-time operation of energy storage systems in a residential building equipped with a PV system, heat pump (HP), and thermal and electrical energy storage systems. The results of this research demonstrate to rooftop PV system owners that investment in combined TSS and battery can be more profitable as this system can minimise life cycle costs. This thesis also presents an analysis of the potential impact of residential HP systems into reserve capacity market. This research presents a business aggregate model for controlling residential HPs (RHPs) of a group of houses that energy aggregators can utilise to earn capacity credits. A control strategy is proposed based on a dynamic aggregate RHPs coupled with TES model and predicting trading intervals capacity requirements through forecasting demand and non-scheduled generation. RHPs coupled with TES are optimised to provide DSM reserve capacity. A rebound effect reduction method is proposed that reduces the peak rebound RHPs power.

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Eriksson, Rickard, and Pontus Andersson. "Thermal storage solutions for a building in a 4th generation district heating system : Development of a dynamic building model in Modelica." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-40114.

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The world is constantly striving towards a more sustainable living, where every part of contribution is greatly appreciated. When it comes to heating of buildings, district heating is often the main source of heat. During specific times, peak demands are created by the tenants who are demanding a lot of heat at the same time. This demand peak puts a high load on the piping system as well as the need for certain peak boilers that run on non-environmental friendly peak fuel. One solution that is presented in this degree project that solves the time difference between production and demand is by utilizing thermal storage solutions. A dynamic district heated building model is developed with proper heat propagation in the pipelines, thermal inertia in the building and heat losses through the walls of the building. This is all done utilizing 4th generation district heating temperatures. Modelica is the tool that was used to simulate different scenarios, where the preheating of indoor temperature is done to mitigate the possibility for demand peaks. Using an already existing model, implementation and adjustments are done to simulate thermal storage and investigate its effectiveness in a 4th generation district heating system. The results show that short-term energy storage is a viable solution in concrete buildings due to high building mass. However, combining both 4th generation district heating with storage in thermal mass is shown not to be suitable due to low temperatures of supply water, which is not able to increase the temperature of the building’s mass enough.

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Ximenes, Naves Alex. "Whole Life Sustainability Assessment at the Building Industry and Constructed Assets, through the Whole Life Costing Assessment and Life Cycle Costing Assessment evaluating the economic and financial aspects." Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/670202.

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Els edificis d’energia neta poden ser entesos com a edificis, que durant un temps determinat generen tanta energia com consumeixen. Ja sigui des del punt de vista de l’oferta o el consum, la disponibilitat d’energia està relacionada amb alguns aspectes bàsics, com ara la font (s), la conversió, la distribució, l’ús, el malbaratament, l’optimització, l’eficiència i l’autonomia. Aquests temes revelen la complexitat del tema de l'energia i justifiquen l'atenció especial que li dóna la comunitat acadèmica. Per obtenir resultats tangibles en l'anàlisi d'aquests sistemes, en el nostre estudi ens centrem en la modelització i optimització de solucions energètiques aplicades a edificis o sistemes similars. D'altra banda, el període de temps dels objectes analitzats es va estendre fins al seu període de cicle de vida previst. Es van establir els objectius principals com: - Verificar i analitzar l’estat de la tecnologia de les energies renovables per a edificis i actius construïts i l’aplicabilitat de l’anàlisi de costos del cicle de vida a aquests temes; - Configurar models reproductibles d’edificis i les seves principals càrregues elèctriques, mitjançant eines d’enginyeria de processos assistits per ordinador, per procedir a simulacions i optimització, considerant-se com a font d’energia primària l’energia solar; - Quantificar, utilitzant estudis de casos reals i hipotètics, els beneficis de les solucions proposades, amb l'objectiu de realitzar tota l'avaluació de la sostenibilitat de la vida mitjançant la reducció de tot el cost del cicle de vida;
Los edificios de energía de red cero pueden entenderse como edificios, que durante un tiempo dado generan tanta energía como consumen. O bien, desde el punto de vista del suministro o el consumo, la disponibilidad de energía está relacionada con algunos problemas básicos, como las fuentes, la conversión, la distribución, la utilización, el desperdicio, la optimización, la eficiencia y la autonomía. Estos problemas revelan la complejidad del tema de la energía y justifican la atención especial que le presta la comunidad académica. Para obtener resultados tangibles en el análisis de estos sistemas, en nuestro estudio nos centramos en el modelado y la optimización de soluciones energéticas aplicadas a edificios o sistemas similares. Por otro lado, el período de tiempo de los objetos analizados se extendió a su período de ciclo de vida esperado. Los objetivos principales se establecieron como: - Verificar y analizar el estado de la técnica de las soluciones de energía renovable para edificios y activos construidos y la aplicabilidad del análisis de costos de ciclo de vida a estas cuestiones; - Configure modelos reproducibles de edificios y sus principales cargas eléctricas, a través de herramientas de Ingeniería de Procesos Asistidos por Computadora, para proceder a simulaciones y optimización, considerando como fuente de energía primaria la energía solar;
Net-zero energy buildings can be understood as buildings, that for a given time, generate as much energy as they consume. Either, from the point of view of supply or consumption, energy availability is related to some basic issues such as source (s), conversion, distribution, utilization, waste, optimization, efficiency and autonomy. These issues reveal the complexity of the subject of energy and justify the special attention given to it by the academic community. To obtain tangible results in the analysis of these systems, in our study we focus on the modelling and optimization of energy solutions applied to buildings or similar systems. On the other hand, the time frame of the analysed objects was extended to their expected life cycle period. The main objectives were stablished as: - Verify and analyse the state-of-the-art of renewable energy solutions for buildings and constructed assets and the applicability of life cycle costing analysis to these issues; - Configure reproducible models of buildings and their main electrical loads, via Computer Aided Process Engineering tools, to proceed simulations and optimization, considering as primary energy source solar energy; - Quantify, using real-life and hypothetical case studies, the benefits of the proposed solutions, aiming the whole life sustainability assessment through the reduction of the whole life cycle costing; and - Guarantee the reproducibility of the models and main general results of this study and make them public, to contribute with their applicability and further researches.

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Revholm, Johan. "Energisimulering av kvarteret Hästskon 9 och 12 med ombyggnad och termiskt akviferlager." Thesis, KTH, Uthålliga byggnadssystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-124630.

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Detta examensarbete utreder lönsamheten i en systemlösning för termiskt akviferenergilager tillsammans med ny VVS-teknisk lösning i fastigheterna kv Hästskon 9 och 12 vid en föreslagen framtida helrenovering. Dessutom utreds förutsättningar för miljöklassning i energi- och miljöcertifieringssystemet Miljöbyggnad avseende energianvändning, dagsljuskomfort, solvärmelast och termisk komfort för om- och tillbyggnadsförslaget med målsättning på nivå GULD. Genom att utnyttja akviferen under fastigheterna kvarteret Hästskon 9 och 12 idag kan man åstadkomma mycket låg energianvändning med en säsongsenergiverkningsgrad via kylmaskiner för värme- och kylaförsörjning på 5,6. En LCC-kalkyl visar att det finns en energikostnadsbesparing för fastighetsägaren Vasakronan omkring 3,65 MSEK per år jämfört med dagens situation om den beskrivna akviferlösningen används. Det ger en återbetalningstid om cirka 4,5 år på investeringen som måste göras. Energiklassning i Miljöbyggnadssystemet för befintliga fastigheter är troligtvis möjlig utan andra åtgärder än akviferlagersystemet, men då med BRONS eller möjligtvis SILVER nivå. Vid ett framtida om- och tillbyggnadsförslag får fastighetsägaren cirka 13 000 m² ytterligare uthyrbar lokalyta för handelslokaler och kontor. Trots detta kan energianvändningen minska ännu mer tack vare en säsongsenergiverkningsgrad via kylmaskiner för värme- och kylaförsörjning på 7,0 då SEB:s datakylanläggning kvarstår med värmeåtervinning på fastigheternas värmesystem, värme- och kylsystem byggs om för låg värmebärartemperatur och hög köldbärartemperatur, luftbehandlingssystem optimeras för låg fläktelenergi och hög värmeåtervinningsgrad, glaslösningar väljs med hänsyn till begränsad solinstrålning och byggnadens klimatskärm tilläggsisoleras i viss omfattning. Energikostnadsbesparingen ökar då ytterligare framåt 4,8 MSEK per år jämfört med dagens situation. Även om SEB:s datakylanläggning faller bort vid en ombyggnad finns ändå möjligheten att självständigt försörja fastigheten med egenproducerad värme via ytterligare en värmepump, vilket avlägsnar beroendet av SEB IT:s datahall för värmeproduktion och ändå ger en energikostnadsbesparing på 4,25 MSEK per år jämfört med dagens situation. Vid en sådan lösning blir den specifika energianvändningen enligt BBR 2012:s definition endast cirka 30 kWh/m² Atemp, år. Denna siffra är mycket lägre än nybyggnadskraven i BBR 2012 och i klass med nyproducerade byggnader med borrhålsenergilager. Utifrån analysen av Miljöbyggnadssystemets indikatorer för energianvändning, solvärmelast, dagsljuskomfort och termisk komfort bedöms det möjligt att klassa kvarteret Hästskon 12 och 9 vid om- och tillbyggnad i klass GULD med vissa förändringar av om- och tillbyggnadsförslaget. För att uppnå klass GULD med hänsyn till dagsljuskomfort och solvärmelast krävs särskild anpassning av glasning på S-huset, M-husets fasad mot Malmskillnadsgatan, samt en stor ljusgård i H-huset för att släppa in tillräckligt mycket dagsljus samtidigt som man åstadkommer effektiv solavskärmning.
This thesis investigates the viability of a system solution for aquifer thermal energy storage along with new HVAC technical solutions in real estates Hästskon 9 and 12 at a proposed future renovation. It also explores opportunities for certification in the Swedish energy and environmental certification system Miljöbyggnad (Environmental Building) regarding energy consumption, daylight comfort, solar heat load and thermal comfort for the renovation and extension proposal of Hästskon 12 with the goal of the GOLD level. By exploiting the aquifer in the properties Hästskon 9 and 12 today, very low energy consumption is achievable with seasonal energy efficiency via chillers for heating and cooling supply of 5.6. The LCC analysis shows that there are energy cost savings for property owner Vasakronan of about 3.65 million SEK per year compared to the current situation, if the described aquifer thermal energy storage solution is used. This gives a payback time of approximately 4.5 years in the investment to be made. Certification in the Miljöbyggnad system for existing buildings is probably possible with the aquifer thermal energy storage, but with BRONZE or possibly SILVER level. In the future refurbishment and extension proposal, the property owner adds about 13 000 m² of additional rentable commercial premises and offices. Nevertheless, the energy use of the properties decreases further owing to a seasonal energy efficiency via chillers for heating and cooling supply of 7.0 when the data centre refrigeration equipment for tenant SEB persists with heat recovery on the properties' heating systems, heating and cooling systems are adapted for low heat carrier temperature and high brine water temperature, ventilation systems are designed for low fan electricity demand and high heat recovery rate, glass solutions chosen are based on limited solar radiation and the building envelope is additionally insulated to some extent. Energy cost savings are furthered to 4.8 million SEK per year compared to the current situation. Even if the data centre refrigeration equipment for tenant SEB is closed down in a future refurbishment scenario, there is possibility to independently supply the property with its own heat produced by an additional heat pump, which removes the dependence of tenant SEB's data centre for heat supply and yet provides an energy saving of 4.25 million SEK per year compared the current situation. Such a solution will result in specific energy with the BBR 2012 (Swedish building regulations) definition of only about 30 kWh / m² Atemp, year. This figure is much lower than new construction requirements of BBR 2012 and on par with virgin buildings with borehole energy storage system. Based on the analysis of the Miljöbyggnad system indicators for energy, solar thermal load, daylight comfort and thermal comfort it is possible to certify Hästskon 12 and 9 in a future refurbishment and extension at GOLD level with some changes in the refurbishment proposal. In order to achieve GOLD level with respect to daylight comfort and solar heat load, special adaptation of the glazing on the S building, M building's facade facing Malmskillnadsgatan, and a large atrium in the H-building is required to let in enough natural light while still providing effective solar shading.

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Aldaouab, Ibrahim. "Optimization and Control of Smart Renewable Energy Systems." University of Dayton / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1567770026080553.

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Pereira, Ricardo Jorge da Silva. "Design and optimization of building integration PV/T systems (BIPV/T)." Master's thesis, Universidade de Évora, 2015. http://hdl.handle.net/10174/13382.

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Neste trabalho é analisado, por via numérica e experimental, o comportamento térmico e eléctrico de um sistema fotovoltaico/térmico integrado em edifício, recorrendo a material de mudança de fase para regularização da diferença de temperatura entre interior e exterior e para a estabilização da temperatura do módulo fotovoltaico. Foi realizado uma revisão da literatura sobre o tema. Um modelo de cálculo dos fenómenos de transferência de calor e massa foi desenvolvido, assim como da produção de energia eléctrica, e implementado em software de cálculo Matlab/Simulink®. Paralelamente foram conduzidos ensaios experimentais a fim de analisar o comportamento térmico do sistema e respectiva validação do modelo numérico. De modo a melhorar a eficiência total do sistema, foi aplicado um processo de optimização com o método dos algoritmos genéticos. Do estudo, conclui-se que o sistema pode alcançar uma eficiência máxima total de 64% na configuração de inverno e de 32% na configuração de verão; ABSTRACT: This work presents a numerical and experimental analysis of the thermal and electrical performance of a building integrated photovoltaic/thermal system (BIPV/T), with the use of phase change material for stabilize the temperature difference between indoors and outdoors and a rapid stabilization of the PV modules’ temperature. A literature review was conducted on the topic. A calculation model was developed of the heat and mass transfer phenomena, as well as a model of a photovoltaic module, which were implemented in Matlab/Simulink®. Experimental tests were performed to analyze the thermal performance of the system and the validation of the numerical model. To improve overall system efficiency, an optimization process with the method of genetic algorithms was applied. From the study, it is concluded that the system can achieve a maximum total efficiency of 64% with winter configuration and 32% with summer configuration.

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Achard, Patrick. "Etude et caractérisation de parois d'enveloppe de bâtiment intégrant un matériau à changement de phase et constituant une interface modulable permettant la captation de l'énergie solaire et la gestion des ambiances intérieures." ENMP, 1986. http://www.theses.fr/1986ENMP0016.

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Analyse de l'évolution des materiaux et des techniques ainsi que des consequences induites par celles-ci sur la conception du bati. Importance du concept de masse (ou inertie) quant a son influence sur le comportement thermique du batiment vis a vis du rayonnement solaire. Etat des connaissances sur les materiaux presentant un changement de phase, utilisables dans les parois du batiment. Modelisation physique, experimentation sur modeles reduits et a l'echelle 1; methodes numeriques de traitement du signal

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Metchueng, Kamdem Syntia. "Stockage de chaleur dans l'habitat par sorption zéolite/H2O." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI059/document.

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Le couple zéolite/H2O, qui présente une densité énergétique importante et remplit les conditions d’innocuité requises pour un système de stockage de chaleur pour l’habitat, est mis en œuvre dans réacteur modulaire à lit fixe. Un modèle monodimensionnel de transferts couplés de masse et de chaleur dans un lit fixe de grains de zéolite parcourus par un flux d'air humide été élaboré. Ce dernier a été conçu de façon à pouvoir intégrer rapidement des données sur de nouvelles générations de matériaux et coupler le réacteur à d’autres modèles : bâtiment/sous-station/quartier. L'étape de validation expérimentale montre que le modèle permet une estimation satisfaisante de l'autonomie, la durée d'amorçage et la puissance moyenne fournie en phase de décharge ainsi que la durée de charge. Ce modèle est donc un bon outil de dimensionnement et de pilotage du réacteur. L'analyse de sensibilité a montré que l'amélioration des prévisions du modèle requiert une évaluation plus précise de la chaleur complémentaire de sorption et de la porosité du lit. Après avoir estimé les besoins de chauffage d'une maison BBC deux dimensionnements ont été proposés afin d'effacer soit l'hyper-pointe de 18h - 20h soit la semaine la plus froide. Si la première stratégie aboutit à un système de stockage plus compact, la seconde permet de réduire le nombre de cycles marche/arrêt. Pour un îlot de 50 maisons BBC, la notion de foisonnement est considérée lors de l'estimation des besoins en chauffage pendant la semaine la plus froide. La phase de charge du système de stockage se ferait par le biais de la chaleur fatale récupérée dans l'industrie. Pour des stratégies d'effacement similaires (semaine la plus froide en hiver), un volume équivalent de 544 litres par maison dans l'îlot suffit pour répondre aux besoins de chauffage à Nancy contre 580 litres pour une maison BBC seule
Heat storage systems for residential house heating could contribute to smoothing the load curve and would help prevent the use of the most polluting power plants or electricity imports during consumption peaks. Thermochemical heat storage systems are suitable for the intended application since they have high energy densities and low thermal losses. This thesis focuses on the design of an adsorption heat storage system that would be used to shed the load curve of the heating device of a house or residential district during the winter peak consumption periods. The zeolite/H2O pair, which has interesting features such as a high energy density and meets the conditions of safety required for a heat storage system for housing, is implemented in a modular fixed bed reactor. A 1D pseudo-homogeneous model was developed in order to simulate the performance of a fixed bed of zeolite during the adsorption and desorption of water. The latter was designed so as to facilitate the integration of data on new generations of materials and model couplings. The need to obtain data on the sorption properties of the zeolite/H2O pair to have reliable simulation results has been demonstrated, particularly at low partial pressures of water vapor and under the operating conditions selected. The experimental validation phase shows that the pseudo-homogeneous model provides a satisfactory estimate of criteria such as the autonomy, the responsiveness and the average power delivered during the discharging phase and the charging time. The model is thus a good sizing and management tool of the reactor. A sensitivity analysis, with the method of Morris, showed that improved model estimates require a more accurate assessment of the additional heat of sorption and porosity of the bed. After assessing the heating needs of the LEB house with a thermal model of the latter in cold climate conditions, two heat storage reactors were sized in order to shed the heating system's load curve either between 6 and 8pm or during the coldest week of the year. While the first strategy results in a more compact storage system, the second makes it possible to reduce the number of on/off cycles. The need for predictive control for monitoring the storage system was highlighted. As for the residential district of 50 LEB houses, diversity is considered when estimating the heating needs of the latter during the coldest week in Nancy. The heat source during the charging phase of the container would be industrial waste heat. During the coldest week, two sizings are suggested. For similar load shedding strategies, the comparison of the equivalent storage volume per house in the district with the storage volume for a single house serves highlights the importance of taking into account diversity. In order to meet the heating needs in Nancy, an equivalent volume of 544 liters per house in the district is sufficient whereas 580 liters are needed for a LEB house

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Ranjith, Adam. "Thermal Energy Storage System Construction." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264530.

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In the framework of 2020 PUPM HEAT project three different types of thermal energy storage (TES) systems are being constructed and analyzed at a demonstration site set up at the power plant IREN in Moncalieri, Italy. KTH will assist this project by setting up a validation rig where three TES systems in smaller dimensions will be constructed and analyzed for its performance, to use as guideline for the demonstration site rig. The first TES system that is being constructed is the submerged parallel spiral heat exchanger which is a completely new version of latent heat storage to be tested. For this idea, parallel layers of spiral copper coils will fill up a tank shell which in turn will be filled with phase change material. By injecting high temperature heat transfer fluid, phase change material will change its state and energy will be stored in the system. When injecting low temperature heat transfer fluid, the energy will be extracted. This BSc thesis will present detailed design solutions for the tank shell and the spiral copper coils that will be used for the heat exchanger. Presented solutions are then used to order parts needed to initiate the construction phase.
Inom ramverket för 2020 PUPM HEAT projektet kommer tre olika typer av värmeenergilagrings enheter tillverkas och analyseras vid energikraftverket IREN i Moncalieri, Italien. KTH kommer att assistera detta projekt genom att sätta upp en anläggning med tre liknande värmeenergilagrings enheter i mindre dimensioner som kommer konstrueras och analyseras. Dess data kommer sedan användas som riktlinje för att tillverka de större värmeenergilagringsenheterna i IREN. Den första enheten som tillverkas är en värmeväxlare som bygger på en ny version av latent energilagring. Den kommer att bestå av parallella lager av spiral formade koppar rör som fyller en tank. Tomrummet som blir över kommer att fyllas upp av fasändrings material (PCM). Genom att injicera varmt vatten i systemet kommer PCM:et att byta fas, vilket resulterar i att värmeenergin lagras i systemet. När sedan kallt vatten injiceras kan den sparade energin bli utvunnen. Den här rapporten kommer att presentera designen till tank kåpan såväl som den inre strukturen med kopparrör som behövs till värmeväxlaren. Resultatet ska möjliggöra beställning av alla delar som behövs för att konstruera värmeväxlaren.

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Hongois, Stéphanie. "Stockage de chaleur inter-saisonnier par voie thermochimique pour le chauffage solaire de la maison individuelle." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00665612.

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Les actions conjointes en faveur d'une meilleure isolation du bâti et de l'expansion des énergies renouvelables dans l'habitat jouent un rôle de premier plan dans la politique de réduction des gaz à effet de serre et la recherche d'une plus grande efficacité énergétique. La présente thèse vise à développer un système de stockage de chaleur par voie thermochimique dédié au chauffage solaire d'une maison individuelle. A cet effet, un matériau de stockage spécifique à été mis au point, à base de zéolithe et de sulfate de magnésium. Le principe, reposant sur un phénomène mixte d'adsorption physique de vapeur d'eau et de réaction chimique d'hydratation, est à caractère inter-saisonnier : en été, la chaleur issue de capteurs solaires thermiques à air est stockée par le matériau, qui se déshydrate selon une réaction endothermique ; en hiver, l'exothermicité de la réaction inverse est exploitée afin de chauffer l'habitat. Après un état de l'art des technologies de stockage thermique, un protocole de préparation de ce matériau composite innovant est établi. Des travaux de caractérisation sont alors entrepris à l'échelle micro et macroscopique. A partir de ces données expérimentales macroscopiques, le système de stockage est dimensionné en fonction des besoins en chaleur pour le chauffage d'une maison individuelle de type Bâtiment Basse Consommation. A l'issue de cette étude, un modèle de réacteur de stockage thermique est élaboré, afin d'interpréter les transferts couplés de matière et de chaleur intervenant dans le lit de matériau et d'optimiser le réacteur de stockage en conséquence. La validité du modèle est ensuite testée et discutée à la lumière des résultats expérimentaux.

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Bembry, Walter T. IV. "Emergency thermal energy storage: cost & energy analysis." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13086.

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Master of Science
Department of Mechanical Engineering
Donald Fenton
The need to store and access electronic information is growing on a daily basis as more and more people conduct business and personal affairs through email and the internet. To meet these demands, high energy density data centers have sprung up across the United States and around world. To ensure that vital data centers run constantly, proper cooling must be maintained to prevent overheating and possible server damage from occurring. Emergency cooling systems for such systems typically utilize traditional batteries, backup generator, or a combination thereof. The electrical backup provides enough power to support cooling for essential components within the data centers. While this method has shown to be reliable and effective, there are several other methods that provide reliable emergency cooling at a fraction of the cost. This paper address the lack of information regarding the initial, operation, and maintenance costs of using Thermal Energy Storage (TES) tanks for emergency cooling. From research and various field examples, five emergency cooling system layouts were designed for various peak cooling loads. Looking at the different cooling loads, components, and system operations an economic evaluation of the system over a 20 year period was conducted. The economic analysis included the initial and maintenance costs of each system. In an effort to better understand power consumption of such systems and to help designer’s better estimate the long term costs of TES tanks systems, five layouts were simulated through a program called TRNSYS developed for thermal systems. To compare against current systems in place, a benefit to cost ratio was done to analyze TES versus a comparable UPS. The five simulated systems were one parallel pressurized tank, one parallel and one series atmospheric tank, one parallel low temperature chilled water, and one series ice storage tank. From the analysis, the ice storage and pressurized systems were the most cost effective for 1 MW peak cooling loads. For 5 MW peak cooling loads the ice storage and chilled water systems were the most cost effective. For 15 MW peak loads the chilled water atmospheric TES tanks were the most cost effective. From the simulations we concluded that the pressurized and atmospheric systems consumed the least amount of power over a 24 hour period during a discharge and recharge cycle of the TES tank. From the TRNSYS simulations, the ice storage system consumed 22 – 25% more energy than a comparable chilled water system, while the low temperature storage system consumed 6 – 8% more energy than the chilled water system. From the benefit-cost-ratio analysis, it was observed that all systems were more cost effective than a traditional battery UPS system of comparable size. For the smaller systems at 1 MW the benefit-cost-ratio ranged between 0.25 to 0.55, while for larger systems (15 MW) the ratio was between 1.0 to 3.5 making TES tanks a feasible option for providing emergency cooling for large and small systems.

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Ugur, Burcu. "Thermal Energy Storage in Adsorbent Beds." Thesis, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24362.

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Total produced energy in the world is mostly consumed as thermal energy which is used for space or water heating. Currently, more than 85% of total thermal energy consumption is supplied from fossil fuels. This high consumption rate increases the depletion risk of fossil fuels as well as causing a tremendous release of hazardous gases such as carbon dioxide, carbon monoxide, sulfur oxides, nitrogen oxides and particulate matter that effects both environment and human health. Those drawbacks force humankind to search for new technologies, like renewables, to reduce fossil fuel dependency on thermal energy production. Thermal energy storage in adsorbent beds is one of the resulting technologies. Adsorption is an exothermic process in which a fluid (adsorbate) diffuses into the pores of a porous solid material (adsorbent) and trapped into the crystal lattice. In this system, exothermic adsorption of water vapor from air is carried out by using hybrid adsorbent of activated alumina and zeolite. In previous studies, through literature review, this adsorbent was selected to be the most efficient adsorbent for this process due to its high water adsorption capacity, high heat of adsorption, and stability [Dicaire and Tezel, 2011]. In this study, previous studies started on this project was confirmed and pursued by trying to increase the efficiency of the process and confirm the feasibility and applicability of this system in larger scales. In this thesis, various zeolite and activated alumina hybrid adsorbents with varying zeolite compositions were screened to find the most efficient adsorbent for thermal energy storage process that gives the highest energy density. Then, existing small column was replaced with a new one, which is 16 times bigger in volume, in order to confirm the feasibility of this process at larger scales. Applicability of on-off heat release in adsorption process was also investigated by conducting several on-off experiments at different on-off time periods. Moreover, exothermic adsorption process was modeled by doing mass and energy balances in the column, water accumulation balance in the pellets, and energy balance in the column wall. Validity of this model was confirmed by comparing it with experimental results at different column volumes, and at different volumetric flow rates. Finally, an overall plant design, capital cost and thermal energy price estimations were done for adsorption thermal energy storage plants for different storage capacities and payback periods.

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Berglund, Simon. "Rock cavern as thermal energy storage." Thesis, Luleå tekniska universitet, Energivetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79596.

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In the fall of 2019, a comprehensive idea study was conducted on heat storage in two rock caverns located at Näsudden in Skelleftehamn and was part of the project course "Energiteknik, huvudkurs" at Luleå University of Technology. This idea study investigated the conditions of using waste heat from Boliden AB:s copper smeltery (Rönnskär) and storing this waste heat in two rock caverns and use them as seasonal thermal storage tanks, with the purpose of using the heat in the nearby district heating network, thus replacing some of the oil burned at Rönnskär. To investigate this, the authors of the idea study looked at two different storage cycles of seasonal storage and modeled this in ANSYS Fluent to simulate the heat storage and the heat losses. The results from this idea study showed promising results for using these caverns as heat storage and this work is therefore a continuation of the idea study. Since the study provided a good understanding of the conditions for seasonal storage, some questions arose about how the rock caverns will behave during an intermittent operation, which is the planned mode of operating the caverns in case of deployment. In this thesis, intermittent operation of these caverns are explored and how this effects the temperature in the caverns and its surrondings, the charge/discharge speed, how insulated walls affect the operation and how much oil is replaced. At the beginning of this project a review of the idea study and similar projects was done to gain deeper knowledge about the subject, but also to get a wider grasp on the different problems that could arise during the thesis. Relevant data for the caverns was collected and acquired to get a deeper understanding of its geometry, layout and what kind of modifications are really possible. Further data from the district heating networks of Boliden AB and Skellefteå Kraft was acquired. The available waste heat from Rönnskär was examined and used to calculate the chargeable energy by hour for the caverns, with the limits of Skelleftehamn district heating network in mind. By examining the different steam boiler patterns, the discharge pattern could be calculated. Using CFD, the unknown global heat transfer coefficient between the cavern water and the cavern wall can be determined. This data was then used with a set of differential equations to model the behavior of the caverns in Simulink. This allowed to determine the behavior for the caverns during normal operation, such as how the heat losses evolve, how the temperatures fluctuate, how much heat the caverns can be charged with and how much they can discharge. The results from the simulations showed that the caverns discharge a higher amount of energy when operating intermittently than when operating seasonally. Depending on how the caverns are utilized, different amounts of discharged energy are obtained. This range from 2224,7MWh to 7846,1MWh for the different discharging patterns. The usage also affects the efficiency of the cavern giving the efficiency a range between 19% to 53,9%. The heat losses range from around 20kW to 1000kW, depending on operation. Insulating the cavern walls reduces on average the heat losses by a factor of 5. Operating the caverns intermittently would on average remove a total of 29 ktonne CO2 and 88,74 tonne NOx for its expected lifespan of 30 years. Economically, the rock caverns have good economic potential as they would save about 80 million SEK during their lifetime just from buying less oil.
Hösten 2019 genomfördes en omfattande idéstudie om värmelagring i två bergrum vid Näsudden i Skelleftehamn och var en del av projektkursen "\textit {Energiteknik, huvudkurs}" vid Luleå tekniska universitet. Denna idéstudie undersökte villkoren för att använda spillvärme från Boliden AB:s kopparsmältverk (Rönnskär) och lagra denna värme i bergrummen och använda dem som säsongslagrade ackumulatortankar. Syftet med detta var att använda värmen i det närliggande fjärrvärmenätverket och därmed ersätta en del av den förbrända oljan hos Rönnskär. Författarna utforskade detta genom att undersöka två olika lagringscykler för säsongslagring och modellerade detta i ANSYS Fluent för att simulera värmelagring och värmeförluster. Resultaten från idéstudien visade lovande resultat för säsongsbaserad värmelagring i dessa bergrum och detta arbete är därför en fortsättning av idéstudien. Eftersom studien gav en god förståelse för förhållandena för säsongslagring, uppstod några frågor om hur bergrummen kommer att bete sig under en intermittent drift, vilket är den planerade driften av bergrummen vid en framtida användning. I detta projekt undersöks intermittent drift av dessa bergrum och hur detta påverkar temperaturen i bergrummen och dess omgivning, laddnings- / urladdningshastigheten, hur isolerade väggar påverkar driften och hur oljeförbrukningen reduceras. I början av detta projekt gjordes en genomgång av idéstudien och liknande projekt för att få djupare kunskap om ämnet, men också för att få ett bredare grepp om de olika problem som kan uppstå under arbetets gång. Relevant data för bergrummen samlades in och anskaffades för att få en djupare förståelse för dess geometri, layout och vilken typ av ändringar som verkligen är möjliga. Ytterligare data från fjärrvärmenätverket för Boliden AB och Skellefteå Kraft förvärvades. Den tillgängliga spillvärme från Rönnskär undersöktes och användes för att beräkna den urladdningsbara energin per timme för bergrummen, med begränsningarna i Skelleftehamns fjärrvärmenät i åtanke. Genom att undersöka de olika ångpannmönstren kan urladdningsmönstret beräknas. Med hjälp av CFD kan den okända globala värmeöverföringskoefficienten mellan bergrumsvattnet och bergväggen bestämmas. Denna data användes sedan med en uppsättning differentialekvationer för att modellera driften av bergrummen i Simulink. Detta gjorde det möjligt att bestämma beteendet för bergrummen under normal drift, till exempel hur värmeförlusterna utvecklas, hur temperaturen fluktuerar, hur mycket värme bergrummen kan laddas med och hur mycket de kan ladda ur. Resultaten från simuleringarna visade att bergrummen kan ladda ur en större mängd energi än vid en säsongsbetonad drift. Beroende på hur grottorna utnyttjas erhålls olika mängder urladdad energi. Detta sträcker sig från 2224,7MWh till 7846,1MWh för de olika urladdningsmönstren. Användningen påverkar också grottans effektivitet vilket ger en effektivitet mellan 19% och 53,9%. Värmeförlusterna sträcker sig från cirka 1000 kW till 20kw, beroende på drift. Isolering av bergväggarna minskar i genomsnitt värmeförlusten med en faktor 5. Att använda grottorna intermittent skulle i genomsnitt ersätta totalt 29 kton CO2 och 88,74 ton NOx för den förväntade livslängden på 30 år. Bergrummen har även god ekonomisk potential eftersom de skulle spara cirka 80 miljoner SEK under sin livstid bara från minskade oljekostnader.

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45

Ohannessian, Roupen. "Thermal Energy Storage Potential in Supermarkets." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-140647.

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The objective of this research is to evaluate the potential of thermal energy storage in supermarkets with CO2 refrigeration systems. Suitable energy storage techniques are investigated and the seasonal storage technology of boreholes is chosen to be the focus of the study. The calculations are done for five supermarket refrigeration systems with different combinations of heating systems and borehole thermal energy storage control strategies. The two heating systems analyzed are the ground source heat pump and the heat recovery from the supermarket’s refrigeration system. The simulation results show that the introduction of thermal energy storage in the scenarios with heat pump can reduce the annual total energy by 6.3%. It is also shown that increasing the number of boreholes can decrease the life cycle cost of the system. Moreover, it is established that a supermarket system with heat recovery consumes 8.1% less energy than the one using heat pump and adding thermal energy storage on the heat recovery system further improves the energy consumption by 3.7% but may become costly.

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Alfasfos, Rami. "Cavern Thermal Energy Storage for District Cooling. Feasibility Study on Mixing Mechanism in Cold Thermal Energy Storage." Thesis, KTH, Kraft- och värmeteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-219932.

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Bugaje, Idris M. "Thermal energy storage in phase change materials." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335920.

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Basgall, Lance Edgar. "Thermal energy storage design for emergency cooling." Thesis, Kansas State University, 2010. http://hdl.handle.net/2097/4637.

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Master of Science
Department of Mechanical and Nuclear Engineering
Donald L. Fenton
Emergency cooling systems are applied to any application where the loss of cooling results in damage to the product, loss of data, or equipment failure. Facilities using chilled water for cooling that experience an electrical power outage, even a small one, would cause the chiller to shut down for 20 minutes or more. If emergency cooling is not available, temperatures would continue to increase to dangerous levels, potentially damaging the facility. Examples of facilities that could be protected by having emergency cooling systems are data centers, hospitals, banks, control rooms, laboratories, clean rooms, and emergency shelters among others. This project addresses the current lack of information and methods needed to correctly design emergency cooling systems. Three application uses were investigated for the possible benefits of having emergency cooling systems. The software TRNSYS was used to simulate five typical emergency cooling systems for each of the three applications. The characteristics and differences of the systems developed from the simulations were then analyzed and documented. The five systems simulated include a pressurized chilled water tank (parallel), atmospheric chilled water tank (parallel and series), low temperature chilled water tank (parallel), and ice storage tank (series). Simulations showed that low temperature chilled water tanks were less stratified than regular chilled water tanks by approximately 10%. Simulations also showed that the differences between atmospheric and pressurized tanks were negligible. Each tank discharged energy in the same manner and managed to replenish itself in the same amount of time. Examination of the different system configurations showed that tanks in series with the thermal load have issues with recharging due to its inability to isolate itself from the thermal load. It was also observed that while low temperature chilled water and ice storage tanks had the potential of reducing the storage tank volume, the amount of time ragged cooling will last is decreased by at least a factor of two. The examination of the five systems produced the desired design methodologies needed to address the lack of information on emergency cooling systems. With the reported information designers can effectively engineer systems to meet their needs.

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Oliver, David Elliot. "Phase-change materials for thermal energy storage." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/17910.

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There is a current requirement for technologies that store heat for both domestic and industrial applications. Phase-change materials (PCMs) represent an important class of materials that offer potential for heat storage. Heat-storage systems are required to undergo multiple melt/freeze cycles without any change in melting-crystallisation point and heat output. Salt hydrates are attractive candidates on account of their high energy densities, but there are issues associated with potential crystallisation of lower-hydrates, long-term stability, and reliable nucleation. An extensive review of the PCMs in the literature, combined with an evaluation of commercially available PCMs led to the conclusion that many of the reported PCMs, lack at least one of the key requirements required for use as a heat-storage medium. The focus of this research was therefore to identify and characterise new PCM compositions with tailored properties. New PCM compositions based of sodium acetate trihydrate were developed, which showed improved properties through the use of selective polymers that retard the nucleation of undesirable anhydrous sodium acetate. Furthermore, the mechanism of nucleation of sodium acetate trihydrate by heterogeneous additives has been investigated using variable-temperature powder X-ray diffraction. This study showed that when anhydrous Na2HPO4 was introduced to molten sodium acetate trihydrate at 58°C the hydrogenphosphate salt is present as the dihydrate. On heating to temperatures in the range 75-90°C the dihydrate was observed to dehydrate to form anhydrous Na₂HPO4. This result explains the prior observation that the nucleator is deactivated on heating. The depression of melting point of sodium acetate trihydrate caused by the addition of lithium acetate dihydrate has also been investigated using differential scanning calorimetry and powder X-ray diffraction. It has been possible to tune the melting point of sodium acetate trihydrate thereby modifying its thermal properties. Studies of the nucleation of sodium thiosulfate pentahydrate, a potential PCM, led to the structural characterisation of six new hydrates using single crystal Xray diffraction. All of these hydrates can exist in samples with the pentahydrate composition at temperatures ranging from 20°C to 45°C. These hydrates are: α-Na₂S₂O₃·2H₂O, which formed during the melting of α-Na₂S₂O₃·5H₂O; two new pentahydrates, β-Na₂S₂O₃·5H₂O and γ-Na₂S₂O₃·5H₂O; Na₂S₂O₃·1.33 H₂O, β-Na₂S₂O₃·2H₂O and Na₂S₂O₃·3.67 H₂O, which formed during the melting of β- Na₂S₂O₃·5H₂O. Furthermore, new PCMs in the 75-90°C range were identified. The commercial impact and route to market of several of the PCMs are discussed in the final chapter.

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McTigue, Joshua. "Analysis and optimisation of thermal energy storage." Thesis, University of Cambridge, 2016. https://www.repository.cam.ac.uk/handle/1810/263019.

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The focus of this project is the storage of thermal energy in packed beds for bulk electricity storage applications. Packed beds are composed of pebbles through which a heat transfer fluid passes, and a thermodynamic model of the heat transfer processes within the store is described. The packed beds are investigated using second law analysis which reveals trade-offs between several heat transfer processes and the importance of various design parameters. Parametric studies of the reservoir behaviour informs the design process and leads to a set of design guidelines. Two innovative design features are proposed and investigated. These features are segmented packed beds and radial-flow packed beds respectively. Thermal reservoirs are an integral component in a storage system known as Pumped Thermal Energy Storage (PTES). To charge, PTES uses a heat pump to create a difference in internal energy between two thermal stores; one hot and one cold. The cycle reverses during discharge with PTES operating as a heat engine. The heat pumps/engines require compression and expansion devices, for which simple models are described and are integrated with the packed bed models. The PTES system behaviour is investigated with parametric studies, and alternative design configurations are explored. A multi-objective genetic algorithm is used to undertake thermo-economic optimisations of packed-bed thermal reservoirs and PTES systems. The algorithm generates a set of optimal designs that illustrate the trade-off between capital cost and round-trip efficiency. Segmentation is found to be particularly beneficial in cold stores, and can add up to 1% to the round-trip efficiency of a PTES system. On the basis of the assumptions made, PTES can achieve efficiencies and energy densities comparable with other bulk electricity storage systems. However, the round-trip efficiency is very sensitive to the efficiency of the compression–expansion system. For designs that utilised bespoke reciprocating compressors and expanders, PTES might be expected to achieve electricity-to-electricity efficiencies of 64%. However, using compression and expansion efficiencies typical of off-theshelf devices the round-trip efficiency is around 45%.

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