| Solar photovoltaic/thermal(PV/T)technology organically combines PV modules with solar thermal devices,however,there are still some shortcomings in the use of PV/T systems,for example,air-cooled PV/T systems have low solar thermal efficiency due to low air heat transfer coefficients and insufficient heat transfer with heat-absorbing panels;water-cooled PV/T systems are susceptible to Water-cooled PV/T systems are susceptible to winter icing and rusting of water pipes,which shorten the operation cycle;moreover,the single cooling method of water or air is limited by seasonality,which reduces the year-round practicality of PV/T systems.On the other hand,PV/T systems mostly use single-glass polycrystalline silicon material for PV modules,while there is little involvement about double-glass monocrystalline silicon PV/T systems.This system benefits from better light transmission of PV panels,and the advantages of electrical and thermal performance are more obvious,which is one of the effective measures to improve the working performance of PV/T systems at present.This paper innovatively proposes the air-cooled mode,heat pipe mode and dual-effect mode PV/T system based on double-glass PV modules,in which the L-shaped fin structure increases the heat transfer area of the air-cooled PV/T system,the heat pipe combines with the refrigerant phase change principle to realize the system operation in winter,and the dualeffect mode PV/T system has multiple functions and higher electrical and thermal characteristics.This paper is based on Ansys platform to simulate the constructed air-cooled system model numerically,and another experimental platform is built for the system in three modes to study and analyze the system performance.The work done in this paper is as follows.(1)The numerical simulation results of air-cooled PV/T system show that the system heat collection performance is improved by increasing the air mass flow rate,solar irradiance,and environment conditions,the immediate thermal performance of the project is 49.43%when the air inlet temperature is 288 K.The temperature difference between the import and export reaches 31.63 K,which can meet the indoor heating demand in winter.(2)The results also show that the double-glass monocrystalline PV module has higher photovoltaic performance,and the air-cooled PV/T system has a thermal efficiency and electrical efficiency of 28.72 % and 17.07 %,respectively,with an overall efficiency of73.63 %,and the L-shaped fin structure helps to improve the system performance.The air mass flow rate increased from 0.025 kg/s to 0.045 kg/s,and the overall efficiency of the system increased by 4.63 %.(3)The heat pipe PV/T system was experimented in both summer and winter,and it was found that the system energy loss gradually decreased after increasing the circulating water flow;the system photoelectric and photo-thermal efficiency decreased after the initial temperature of the water tank was increased;the heat gain of the water tank increased by1.14 MJ after increasing the effective heat absorption area of the heat absorption plate.(4)The double-effect PV/T system raises the temperature of 160 L water tank by18.30 °C,and the difference between the maximum of the intake and the discharge air quality is 16.50 °C.the total accumulated power generation reaches 1.46 k Wh,the comprehensive efficiency is 92.96 %,the size of air mass flow and circulating water flow is an important factor for the system to maintain high efficiency throughout the day,comparing the PV/T system proposed in this paper with other devices,it is found that based on The comparison between the PV/T system proposed in this paper and other installations shows that the PV/T system based on double-glass PV modules has good photovoltaic and photothermal performance.Figure [49] table [29] reference [72]... |
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