In this study,the influence of the phase-change cooling storage system on integrating and controlling of the combined cooling,heating,and power system was analyzed through experiments and computational fluid dynamics ...In this study,the influence of the phase-change cooling storage system on integrating and controlling of the combined cooling,heating,and power system was analyzed through experiments and computational fluid dynamics simulations.The model of three-dimensional phase change material plate and cold storage tank was established and verified.The phase change material selected in this study is a eutectic salt with a phase change temperature of 8℃.The thermodynamic performance of the cold storage tank filled with phase change material plates was calculated,and the energy storage and release efficiency of the phase-change cooling storage system was analyzed.The results indicate that the phase change process correlates positively with the heat transfer fluid flow rate.The heat transfer fluid flow rates of 1.2 m^(3)/h,1.6 m^(3)/h,and 2.0 m^(3)/h all allow the phase change material within the encapsulation module to completely solidify within 8 hours;the flow rate required for melting is not less than 2.0 m^(3)/h,and the highest energy storage efficiency is up to 72%.Considering the thermodynamic performance of the phase-change cooling storage system,it is recommended to use a heat transfer fluid flow rate of 1.6 m^(3)/h for the cooling charge process and 2.0 m^(3)/h for the cooling release process.展开更多
Although numerous studies have considered the two traditional operation strategies:following the electric load(FEL)and following the thermal load(FTL),for combined cooling,heating,and power(CCHP)systems in different c...Although numerous studies have considered the two traditional operation strategies:following the electric load(FEL)and following the thermal load(FTL),for combined cooling,heating,and power(CCHP)systems in different case studies,there are limited theoretical studies on the quantification methods to assess the feasibility of these two strategies in different load demands scenarios.Therefore,instead of a case study,we have undertaken a theoretical analysis of the suitable application scenarios for FEL and FTL strategies based on the energy-matching performance between systems'provision and users'demands.To compare the calculation models of energy saving rate(ESR)for FEL and FTL strategies in the left and right sub-regions of the energy-supply curve,a comprehensive parameter(^)that combines three inherently influential factors(off-design operation parameter,energy-matching parameter,and install capacity coefficient)is defined to determine the optimal installed capacity and feasibility of FEL or FTL strategies quantitatively.The results indicate that greater value of x contribute to a better energy saving performance,and FEL strategy shows better performance than FTL in most load demands scenarios,and the optimal installed capacity occurs when the load demand points were located in different regions of the energy-supply curve.Finally,taking a hotel in Beijing as an example,the value of the optimal install capacity coefficient is 0.845 and the FEL strategy is also suggested,and compared to the maximum install capacity,the average values of the ESR on a typical summer day,transition season,and winter can be enhanced by 3.9%,8.8%,and 1.89%,respectively.展开更多
基金supported by the National Key Research and Development Program of China (Grant No.2023YFB4204000)National Key Research and Development Program of China (Grant No.2024YFB4206500)。
文摘In this study,the influence of the phase-change cooling storage system on integrating and controlling of the combined cooling,heating,and power system was analyzed through experiments and computational fluid dynamics simulations.The model of three-dimensional phase change material plate and cold storage tank was established and verified.The phase change material selected in this study is a eutectic salt with a phase change temperature of 8℃.The thermodynamic performance of the cold storage tank filled with phase change material plates was calculated,and the energy storage and release efficiency of the phase-change cooling storage system was analyzed.The results indicate that the phase change process correlates positively with the heat transfer fluid flow rate.The heat transfer fluid flow rates of 1.2 m^(3)/h,1.6 m^(3)/h,and 2.0 m^(3)/h all allow the phase change material within the encapsulation module to completely solidify within 8 hours;the flow rate required for melting is not less than 2.0 m^(3)/h,and the highest energy storage efficiency is up to 72%.Considering the thermodynamic performance of the phase-change cooling storage system,it is recommended to use a heat transfer fluid flow rate of 1.6 m^(3)/h for the cooling charge process and 2.0 m^(3)/h for the cooling release process.
基金This work was supported by the National K ey Research and Development Program of China(Grant No.2016 Y F B 0901405)the Science Fund for Creative Research Groups(No.51621062)the National Natural Science Foundation of China(Grant No.51806117,51236004).
文摘Although numerous studies have considered the two traditional operation strategies:following the electric load(FEL)and following the thermal load(FTL),for combined cooling,heating,and power(CCHP)systems in different case studies,there are limited theoretical studies on the quantification methods to assess the feasibility of these two strategies in different load demands scenarios.Therefore,instead of a case study,we have undertaken a theoretical analysis of the suitable application scenarios for FEL and FTL strategies based on the energy-matching performance between systems'provision and users'demands.To compare the calculation models of energy saving rate(ESR)for FEL and FTL strategies in the left and right sub-regions of the energy-supply curve,a comprehensive parameter(^)that combines three inherently influential factors(off-design operation parameter,energy-matching parameter,and install capacity coefficient)is defined to determine the optimal installed capacity and feasibility of FEL or FTL strategies quantitatively.The results indicate that greater value of x contribute to a better energy saving performance,and FEL strategy shows better performance than FTL in most load demands scenarios,and the optimal installed capacity occurs when the load demand points were located in different regions of the energy-supply curve.Finally,taking a hotel in Beijing as an example,the value of the optimal install capacity coefficient is 0.845 and the FEL strategy is also suggested,and compared to the maximum install capacity,the average values of the ESR on a typical summer day,transition season,and winter can be enhanced by 3.9%,8.8%,and 1.89%,respectively.
