| With the development of society and the improvement of living quality,the prominent problem of building energy consumption has become increasingly apparent.The light-transmitting envelope as a weak link in building thermal performance has become one of the keys to building energy efficiency.The semi-transparent photovoltaic(STPV)window system combines photovoltaic modules with the building light-transmitting envelope structure,which not only uses solar energy to generate clean power,but also meet the needs of building lighting,framing,and aesthetics,and has the potential and advantages of active energy saving.However,due to the particularity of the solar thermal performance of PV exterior windows,the traditional white glass exterior window architectural design parameters and shading settings are not fully applicable to PV exterior windows,and further research is still needed.Therefore,this paper uses the Grasshopper lighting simulation platform coupled with the energy consumption simulation software Energy Plus to simulate the indoor daylighting quality and building energy consumption of double-paned PV windows.Firstly,the indoor daylighting visual comfort experiment of PV external window and the thermoelectric performance test experiment of different structure PV external window are carried out by setting up the experimental platform.Combined with the indexes of s DA and UDI,the indoor dynamic daylighting evaluation index——s UDI is put forward.Secondly,combined the experimental measurement data of indoor daylighting illuminance,PV glass surface temperature and generating capacity under typical meteorological conditions to verify the reliability of the daylighting model and the Energyplus software heat transfer and power model.On this basis,combined with the meteorological conditions of different climatic regions,the building depth and window-to-wall ratio(WWR)were simulated and studied.In addition,in order to further improve the quality of daylighting,the performance of insulating PV windows with dynamic blind was simulated and optimized;Finally,from the point of view of reducing the net energy consumption of building,the effects of double-glazed PV windows on building energy-saving characteristics under different operation modes in cold areas in winter were studied.The significant conclusions from this study are summarized as follows:(1)Due to the difference of spectral selective absorption of solar radiation visible band between amorphous silicon PV window and ordinary white glass,the standard value of natural illuminance in white glass room is not suitable for amorphous silicon PV window.According to the experimental results,the lower threshold of natural illuminance 400 lx which meets the requirement of visual comfort in amorphous silicon PV window is determined,and puts forward dynamic daylighting evaluation index——s UDI.(2)Through the comparative study of insulating PV window and insulating glass window,it is found that the design value of the WWR of the traditional white glass exterior window building is not suitable for PV window.Therefore,with the goal of optimizing indoor daylighting quality and reducing the net energy consumption of building,we obtained the recommended values of the WWR corresponding to the depth of different buildings under different climatic conditions for insulating PV window buildings.The results show that when the building depth is 3m,4m,5m and 6m,the optimal WWR is 40%,50%,50% and60% in hot summer and warm winter VI light climate area and the optimal WWR is 50%,60% and 60% in hot summer and cold winter V light climate area;The recommended WWR is 30%,40%,50% and 60% in cold region category III light climate area.(3)In the Xiamen and Chengdu areas,where air conditioning and cooling loads are predominant,dynamic blinds not only significantly reduce the glare area near the window,but also benefit building energy efficiency.In Taiyuan,where heating requirements are dominant,dynamic blinds can effectively improve indoor daylighting quality,but it also causes a slight increase in building energy consumption.From the perspective of improving indoor natural lighting quality and reducing net energy consumption,the optimal tilt angles of the insulating PV windows with dynamic blind inside in Xiamen,Chengdu and Taiyuan are: 60 °,120 ° and 90 °,respectively.(4)In winter conditions in cold regions,from the consideration of whether to consider the building’s fresh air demand and fresh air load,it is concluded that the air supply and optimized operation mode for double-glazed PV windows not only reduces the building heating energy consumption,but also improves the power generation efficiency of PV cells,more conducive to building energyconservation.The research results of this paper can provide design basis and theoretical support for the design and application of amorphous silicon PV buildings in different climate regions in China. |
