This work investigates the transient behaviour of a phase change material based cool thermal energy storage (CTES) system comprised of a cylindrical storage tank filled with encapsulated phase change materials (PCMs) ...This work investigates the transient behaviour of a phase change material based cool thermal energy storage (CTES) system comprised of a cylindrical storage tank filled with encapsulated phase change materials (PCMs) in spherical container integrated with an ethylene glycol chiller plant. A simulation program was developed to evaluate the temperature histories of the heat transfer fluid (HTF) and the phase change material at any axial location during the charging period. The results of the model were validated by comparison with experimental results of temperature profiles of HTF and PCM. The model was also used to investigate the effect of porosity, Stanton number, Stefan number and Peclet number on CTES system performance. The results showed that increase in porosity contributes to a higher rate of energy storage. However, for a given geometry and heat transfer coefficient, the mass of PCM charged in the unit decreases as the increase in porosity. The St number as well as the Ste number is also influential in the performance of the unit. The model is a convenient and more suitable method to determine the heat transfer characteristics of CTES system. The results reported are much useful for designing CTES system.展开更多
More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the ...More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the parameters of the indoor thermal property in phase change wallboard room and ordinary room,the effects of using phase change wallboards on indoor temperature in summer and air conditioning are obtained. The combination of construct enclosure and phase change materials can stabilize indoor temperature,improve indoor thermal comfort,reduce the frequency of the operation of air conditioning facility,cut the initial investment and operation expense,and meanwhile play an practical role in "the power balancing between the peak period and the valley period" policy. Through the experiment and the test of the effects exerted by phase change wallboard room and ordinary room on the indoor thermal environment,it is obtained that the phase change wallboard can reduce the fluctuation range of indoor temperature and the heat flow from the outside into indoor environment in summer. According to the study,it is found that the effect of cool-storing for 5 h is obvious. Through the analysis of the phase change wallboard without air conditioning in daytime,it is obtained that the frequency of the operation of air conditioning in phase change wallboard room is smaller than that in the ordinary room,which can prolong the lifetime of the facility and reduce operation expense.展开更多
Phase change materials(PCMs) designate materials able to store latent heat.PCMs change state from solid to liquid over a defined temperature range.This process is reversible and can be used for thermo-technical purpos...Phase change materials(PCMs) designate materials able to store latent heat.PCMs change state from solid to liquid over a defined temperature range.This process is reversible and can be used for thermo-technical purposes.The present paper aims to study the thermal performance of an inorganic eutectic PCM integrated into the rooftop slab of a test room and analyze its potential for building thermal management.The experiment is conducted in two test rooms in Antofagasta(Chile) during summer,fall,and winter.The PCM is integrated into the rooftop of the first test room,while the roof panel of the second room is a sealed air cavity.The work introduces a numerical model,which is built using the finite difference method and used to simulate the rooms' thermal behavior.Several thermal simulations of the PCM room are performed for other Chilean locations to evaluate and compare the capability of the PCM panel to store latent heat thermal energy in different climates.Results show that the indoor temperature of the PCM room in Antofagasta varies only 21.1℃±10.6℃,while the one of the air-panel room varies 28.3℃±18.5℃.Under the experiment's conditions,the PCM room's indoor temperature observes smoother diurnal fluctuations,with lower maximum and higher minimum indoor temperatures than that of the air-panel room.Thermal simulations in other cities show that the PCM panel has a better thermal performance during winter,as it helps to maintain or increase the room temperature by some degrees to reach comfort temperatures.This demonstrates that the implementation of such PCM in the building envelope can effectively reduce space heating and cooling needs,and improve indoor thermal comfort in different climates of Chile.展开更多
文摘This work investigates the transient behaviour of a phase change material based cool thermal energy storage (CTES) system comprised of a cylindrical storage tank filled with encapsulated phase change materials (PCMs) in spherical container integrated with an ethylene glycol chiller plant. A simulation program was developed to evaluate the temperature histories of the heat transfer fluid (HTF) and the phase change material at any axial location during the charging period. The results of the model were validated by comparison with experimental results of temperature profiles of HTF and PCM. The model was also used to investigate the effect of porosity, Stanton number, Stefan number and Peclet number on CTES system performance. The results showed that increase in porosity contributes to a higher rate of energy storage. However, for a given geometry and heat transfer coefficient, the mass of PCM charged in the unit decreases as the increase in porosity. The St number as well as the Ste number is also influential in the performance of the unit. The model is a convenient and more suitable method to determine the heat transfer characteristics of CTES system. The results reported are much useful for designing CTES system.
基金Project(50878133) supported by the National Natural Science Foundation of ChinaProject(2007R37) supported by the Program Supporting Excellent Talents of Liaoning Province,China+1 种基金Project(2008S193) supported by the Key Laboratory Fund of Education Department of Liaoning Province,ChinaProject(1071211-1-00) supported by the Scientific and Technical Fund Project Subsidy of Shenyang,China
文摘More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the parameters of the indoor thermal property in phase change wallboard room and ordinary room,the effects of using phase change wallboards on indoor temperature in summer and air conditioning are obtained. The combination of construct enclosure and phase change materials can stabilize indoor temperature,improve indoor thermal comfort,reduce the frequency of the operation of air conditioning facility,cut the initial investment and operation expense,and meanwhile play an practical role in "the power balancing between the peak period and the valley period" policy. Through the experiment and the test of the effects exerted by phase change wallboard room and ordinary room on the indoor thermal environment,it is obtained that the phase change wallboard can reduce the fluctuation range of indoor temperature and the heat flow from the outside into indoor environment in summer. According to the study,it is found that the effect of cool-storing for 5 h is obvious. Through the analysis of the phase change wallboard without air conditioning in daytime,it is obtained that the frequency of the operation of air conditioning in phase change wallboard room is smaller than that in the ordinary room,which can prolong the lifetime of the facility and reduce operation expense.
基金supported by ANID/FONDAP 1522A0002,ANID/FONDAP 1522A0006,ANID/FONDECYT 3210690,MESCyT/FONDOCyT 2018-2019-3C1-069the UAI Earth Research Center。
文摘Phase change materials(PCMs) designate materials able to store latent heat.PCMs change state from solid to liquid over a defined temperature range.This process is reversible and can be used for thermo-technical purposes.The present paper aims to study the thermal performance of an inorganic eutectic PCM integrated into the rooftop slab of a test room and analyze its potential for building thermal management.The experiment is conducted in two test rooms in Antofagasta(Chile) during summer,fall,and winter.The PCM is integrated into the rooftop of the first test room,while the roof panel of the second room is a sealed air cavity.The work introduces a numerical model,which is built using the finite difference method and used to simulate the rooms' thermal behavior.Several thermal simulations of the PCM room are performed for other Chilean locations to evaluate and compare the capability of the PCM panel to store latent heat thermal energy in different climates.Results show that the indoor temperature of the PCM room in Antofagasta varies only 21.1℃±10.6℃,while the one of the air-panel room varies 28.3℃±18.5℃.Under the experiment's conditions,the PCM room's indoor temperature observes smoother diurnal fluctuations,with lower maximum and higher minimum indoor temperatures than that of the air-panel room.Thermal simulations in other cities show that the PCM panel has a better thermal performance during winter,as it helps to maintain or increase the room temperature by some degrees to reach comfort temperatures.This demonstrates that the implementation of such PCM in the building envelope can effectively reduce space heating and cooling needs,and improve indoor thermal comfort in different climates of Chile.
