Experimental And Numerical Investigation Of Precast Concrete Fa?ade Integrated With Photovoltaic Panels And Its Effects On Buildings Energy Consumption

According to research data,energy consumption of buildings accounts for approximately 1/3 of total energy consumption all over the world.Compared to other fields,energy consumption of buildings has become one of the biggest fields.Therefore,green buildings,obtaining energy from renewable energy to reduce the utilization of conventional fossil fuels,have emerged and developed over the past decades.However,some problems,for instant,irreversible damage on concrete wall,additional occupation of space,and negative effects on integral aesthetics of various buildings,have been resulted from traditional building-integrated photovoltaics.Therefore,an innovative precast concrete fa?ade integrated with photovoltaic panels（PVPC fa?ade）that PV panels are inserted into a reserved groove of the precast concrete wall,together with insulation filled into the interspace of the PV panel and concrete wall.The proposed PVPC fa?ade could beautify the appearance of buildings without occupying additional outer space in mega cities particularly.Based on the configuration of PVPC fa?ade,the coupled electrical-thermal model was developed with the solution procedure,and an isotropic model was proposed to convert solar radiation on horizontal surface into solar radiation on tilted surface.Moreover,the prototype of PVPC fa?ade was manufactured in Shanghai,together with an experimental carried out correspondingly.The results illustrates that numerical simulation results has good agreement with experimental data,the root mean square error（RMSE）of which varies from 0.46 to 2.03.It can be conducted that the numerical results are reliable within the error tolerance.Besides,temperature distribution of various layers on typical days proves furtherly that the PVPC fa?ade can reduce the load of air conditioning to some extent.Finally based on the coupled electrical-thermal model,the long-term performance of PVPC fa?ade was ecaluated compared to the concrete wall without PV modules.The results indicate that PV panels in the PVPC fa?ade generate electricity of approximately 62.56 k Wh/m² with air-conditional load reduction of 19.67 k Wh/m² and CO₂reduction of 45.68 kg/m² annually.The simulation results of the electrical and thermal performance on a typical day in winter and summer indicated that daily power generation of PV modules in summer was only 0.17 k Wh/m²,it was 0.27 k Wh/m² in winter.Moreover,by analyzing the influence of key factors such as the thickness of insulation/air gap and wind speed on the electrical and thermal performance of PVPC facade,the insensitivity of amorphous silicon thin film cells to temperature was proved.Besides,several suggestions for optimal design of the PVPC fa?ade were proposed within certain limitation.