Study On The Factors Influent And Adaptability Of Phase Change Thermal Storage Wallboard

Phase change thermal storage wallboard(PCTSW)is a new kind of building envelope that uses the heat storage and release principle to improve the thermal comfort in buildings.The essence of PCTSW is a cyclic process absorbing heat from and releasing heat to the buildings,which is also the heat transferring over time.In order to ensure the full play of energy storage characteristics and the realization of regional adaptability for PCTSW,In this paper,the multi-factors affecting the performance of PCTSW are optimized and analyzed fully,meanwhile,a passive PCTSW module is established and the thermal performance and energy-saving performance in each region are also analyzed.Based on ANSYS,Aiming at the cold storage in the summer of north China,a one-dimensional unsteady heat transfer model of passive PCTSW was established through enthalpy method.The factors on the internal factors,external factors and envelopes factors were optimized and analyzed based on three indexes,i.e.heat storage capacity,lag time and phase change process.The results have shown as following:the indoor side was the best position for the energy storage effect;the optimum thickness of phase change board is 10mm;increasing indoor air flow appropriately was favorable for the heat storage and release effect of PCTSW;the best heat storage was appeared when PCTSW combine with the wallboard of370 mm thickness;the change of wallboard material types had a irregular influence on thermal storage performance;Pearson correlation analysis shown that the thickness of phase change board played a key role in the thermal storage performance.Based on the platform of TRNSYS,a one-dimensional heat transfer process of the PCTSW is adopted through equivalent heat capacity method,and the passive PCTSW module program is complied by FORTRAN.Composite phase change material is prepared by vacuum adsorption method,Then the validity of the passive PCTSW is efficiently verified by the experimental studies,where the average value of relative error is less than 10%compared with the simulation value.With phase change temperature and phase change thickness as variables and according to the two evaluation index(the indoor temperature fluctuation variance and air conditioning degree hours),the passive PCTSW module applied in the cooling area in summer were studied in adaptability and energy saving properties both aspects.For cold region,the optimum condition is phase change temperature of 25-29℃ range and thickness of 10mm;for hot summer and cold winter region,phase change temperature of 26-30℃ range and thickness of 15mm respectively;for hot summer and warm winter region,phase change temperature of 29-33℃ and thickness of 15mm respectively;compared with the reference room,the energy saving effects of the phase change room are all above 20%for the mentioned regions under the optimum working conditions.In this paper,the conclusions of key factors and of adaptability analysis provide an important reference to the application and popularization of PCTSW.