Investigation And Demonstration On Phase Change Heat Storage Coupled With Night Ventilation For Office Building In Typical Cities Of Western China

Night ventilation?NV?and phase change heat storage?PCHS?can improve indoor thermal environment and reduce the use of air conditioner in summer.PCHS coupled with NV technology has become a hot topic in the field of passive building technology.The large diurnal temperature difference in summer of Western China provides favorable climatic conditions for application of PCHS coupled with NV technology.However,vast territory and diverse climate conditions in Western China lead to significant differences in climate between different regions and seasons.The mismatching between phase change temperature?PCT?and outdoor climate conditions in different seasons and the difference of night ventilation potential lead to the applicable period in the application of the technology.In this paper,EnergyPlus is employed to investigate the application effect of PCHS coupled with NV technology in a multi-story office building in ten representative cities in western China.The climatic suitability and seasonal suitability of the technology in transition season and hot season are investigated.The application potential of PCHS,NV and PCHS coupled with NV technology are also taken into consideration.In addition,the relationship between PCHS coupled with NV technology and climatic conditions is obtained.Meanwhile,the application of PCHS coupled with NV technology in an office building in Xi'an is demonstrated.The application effects of the technology in transition season and hot season are analyzed by means of numerical simulation and filed thermal environment test.The main research works are as follows:1.Based on EnergyPlus numerical simulation method,the optimal PCT of phase change materials used in PCHS coupled with NV technology is parameterized.The optimal PCT in transition season and hot season for the selected cities are selected based on the adaptive thermal comfort theory.The optimum PCT varies from 23? to 29? for the ten representative cities of Western China.The optimal PCT in transition season is equal to that in hot season for Nanning?29??and Kunming?23??.Additionally,the optimum PCT in hot season is either 2? higher than that in transition season or equal to that for other cities.2.The effects of PCHS coupled with NV technology,NV technology and PCHS technology on reducing the Intensity of Thermal Discomfort?ITD?are carefully investigated,respectively.A performance-based inverse design method is developed to determine the favorable climate characteristics,which is beneficial to PCHS coupled with NV technology.The reliability of the approach is validated by a case study.It can help architects to obtain the typical climatic characteristics.For the selected cities of Western China,the typical outdoor air dry-bulb temperature(T_out)has the following characteristics:?1?diurnal temperature difference??T?exceeds 6.8?,?2?the average value(T_ave)is quite close to 27?,?3?the maximum value(T_max)is higher 1.7? than the optimum PCT and the minimum value(T_min)is lower 2.7? than the optimum PCT.3.Based on the research results of numerical simulation,the application demonstration of PCHS coupled with NV technology for office buildings in Xi'an is carried out,and field test experiments are conducted on the indoor thermal environment in transition and hot seasons.The experimental results show that the selected PCT based on the numerical simulation analysis can meet the use demand of hot season in Xi'an,and PCHS coupled with NV technology can significantly improve the indoor thermal environment in both transition and hot seasons.Compared with no PCHS coupled with NV technology,PCHS coupled with NV technology can improve indoor thermal stability in transition season and reduce indoor peak air temperature by 1.2? in hot season.