| Although China’s economy has developed rapidly in recent years,the consumption of primary energy is huge,and the environmental pollution caused by it has become increasingly serious.Statistics show that China’s energy consumption structure is severely unbalanced,primary energy consumption is too large,and renewable energy sources such as solar energy and wind energy are relatively small.Improving renewable energy utilization technology is of great significance for energy conservation and environmental protection.At present,the use of solar energy by human beings is mainly divided into solar thermal technology and solar photovoltaic technology.On this basis,some scholars have proposed that PV/T collectors(Photovoltaic/Thermal)can generate heat and electricity at the same time,that is solar photovoltaic photothermal technology.In this paper,the internal structure of the PV/T collector is optimized,and the heat transfer process is simulated,and the influence of the size and flow of the air flow channel on the heat collection efficiency is analyzed.In photovoltaic/air heat collection mode,the optimal air flow channel size is0.025 m,and the energy saving efficiency is 62.08%.In photovoltaic/water heat collection mode,the optimal water flow is 0.14 kg/s,and the overall solar efficiency is 33.52%.The results show that the two working modes of PV/T collectors use solar energy more efficiently than traditional collectors.In order to deeply study the photovoltaic light and heat performance of PV/T collectors,a monolithic PV/T collector experimental platform is set up in this paper.With the increase of water flow,the battery surface temperature,outlet water temperature,water tank temperature,and thermal efficiency of PV/T collectors gradually decrease,while the photoelectric efficiency gradually increases.The optimal working flow of the collector is0.08 m~3/h,at which time the comprehensive solar energy utilization efficiency reaches a maximum of 75.57%.At present,the related literature only tests the performance of a single PV/T collector.This article builds a single collector experimental platform and a comparative performance experimental platform with a comparative PV/T collector and a PV panel.When the test environment is the same,the photovoltaic efficiency of the PV/T collector is 11.51%and 8.13%higher than that of the comparative PV/T collector and PV photovoltaic panel.This shows that the installation of copper tubes on the battery backboard,using circulating water to absorb the heat generated by the battery work,can effectively improve the battery power generation efficiency.When the user has less demand for hot water,the water circulation in the system should be maintained,otherwise the power generation efficiency of the collector will be reduced.Finally,the influence of connection mode and flow rate on the performance of small PV/T hot water system is explored.In this paper,experimental platforms for PV/T collector series and parallel systems are set up to study the effects of connection methods and flow rates on system performance.During the series system test,the optimal working flow is 0.15 m~3/h,and the comprehensive solar energy utilization efficiency reaches68.65%.Compared with a single collector,the temperature rise of the system water tank is greater,and the internal temperature stratification is more obvious.With the increase of the number of series,the photovoltaic solar thermal performance of the collector gradually decreases,so the number of series should not be too much.When testing the parallel system,the optimal working flow is 0.3 m~3/h,and the comprehensive solar energy utilization efficiency is 66.63%.The change of the temperature of each part of the system with the flow rate is the same as that of the monoblock collector.The experimental results show that the overall performance of a series system is higher than a parallel system,so a series system should be used for small PV/T hot water systems.Figure[68]table[17]reference[25]... |
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