| Concentrating photovoltaic(CPV) technology can effectively improve the efficiency of photovoltaic(PV) system, and reduce its electricity cost. But the current CPV system, especially the high concentrating photovoltaic(HCPV) system with the traditional cooling methods almost exists the insufficient heat dissipation to casue the uneven distribution of temperature or too high temperature of the cell module and to decrease the output power. Therefore, this article consider adopting the direct immersion cooling technology to intensify the heat dissipation of cell components in HCPV system, thus improve the efficiency of the system. So this paper studied at a raddiation of 1 sun and 500 suns solar cell immersed by the dimethyl silicone oil was studied respectively. Under the condition of no light, dark characteristics of different kinds of the solar cell were reasearched, 500 X Fresnel-type immersion CPV system was seted up, and the heat dissipation experiments was studied. At the same time, the closely packed cell module was performed by the Fluent through the numerical simulation and the optimization of thermal performance under 500 simulation suns.1. The effects caused by spectrum transmittance decrease from spectral absorption of silicon oil were estimated for three series sub-cells. The results showed the spectrum transmittance losses of Ge sub-cell from spectrum absorption by the silicon oil can theoretically cause small photocurrent loss for the GaInP/GaInAs/Ge triple-junction solar cellt; Compared with cell performances without liquid-immersion, a certain thickness of silicon oil can improve the performance of the triple-junction GaAs solar cell; And the presence of silicone oil, the cell performance decreases with increasing the thickness of silicon oil.2. The influence of the silicon oil immersion and the different thicknesses of silicon oil on electric performance parameters of the cell was studied and an in-depth analysis of the electrical performances changes of the operated cell in silicon oil was performed under 500 X. The results showed that the solar cell module can be cooled effectively by liquid-immersed cooling under 500 X. Critical silicon oil thickness is 6.3 mm for the solar cell immersed in silicon oil under 500 suns in order to achieve enhanced solar cell electrical performance through silicon oil immersion, With the increase of the thickness of silicon oil, the short circuit current(Isc), the maximum power(Pmax) and conversion efficiency(η) increase first, and then decrease as the silicon oil thickness increases, while the open circuit voltage(Voc) decline gradually; At the radiation between 340~600W/m2, silicon oil inlet temperature is the environmental temperature, silicon oil inlet flow rate of 0.025 m/s, the highest temperature of the cell component does not exceed 52 oC. Measured at the same time of immersion cell open circuit voltage temperature coefficient is about-3.57 mV/oC, the short circuit temperature coefficient is 2.25 mA/oC, the conversion efficiency temperature coefficient is-0.0668%/oC.3. The immersion simulated cell without fins experiment and simulation show that the use of silicone oil immersion cooling without fin close components, makes no finned component temperature the right temperature;In immersion thickness of 1.5 mm, silicone oil flow velocity of 8.4m/s, the temperature is 25 oC and concentrated than for 317 X., simulation of average temperature of 60.8oC;The immersion close cell components with fin simulation and optimization show that silicone oil immersion cooling fin close cell components can maintain a lower, more uniform temperature;In immersion thickness of 1.0 mm, silicone oil speed 1.0 m/s, the temperature is 25 oC and concentrated than 500 X, the battery of the average temperature of 63.1 oC;According to the design of the battery component model, the optimal results for 14 mm fin height, fin number 50, substrate thickness 1.5 mm, immersion thickness of 1.0 mm. |
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