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Summary: Spectral beam splitting is a promising technology to achieve the maximum electrical and thermal outputs from concentrating photovoltaic/thermal (CPV/T) systems simultaneously. In this article, a novel CPV/T receiver is proposed by incorporating a fluid based filter together with a solid absorptive filter. The geometry of the receiver is developed for a designed linear flat mirror concentrator. According to the optical transmittance of both fluid based filters and solid absorptive filters, as well as their corresponding merit functions, four fluid filters and two solid filters are determined to be the candidates of the combined filter for the silicon concentrator solar cell. Then, a complete solar radiation propagation process from concentrator to the designed CPV/T receiver is simulated using ray tracing software‐LightTools. The results show that the surface illumination uniformity of the PV module filtered by each combined filter under the linear flat mirror concentrator is higher than 96%. Using 5 g/L CoSO4 solution and HB650 as the combined filter, 33.67% of the concentrated light can be directed to the PV module with the remainder collected by the filter as thermal energy and the silicon CPV cells can convert 27.06% of this energy into electrical power. This contributes to the fact that 92.43% of the light striking the PV module is within 650‐1100 nm, which is the spectral response range of the cell can work efficiently. The total efficiency of 49.88% can be achieved with such a filter and the electrical efficiency is 9.1% with respect to the total incident power on the receiver. [ABSTRACT FROM AUTHOR]

Liquid-immersed III–V concentrator solar cells have been proposed either for providing a new concentrator with high optical performance or for solving the receiver thermal management issue under high concentration. In this paper, the behavior of III–V GaInP/GaInAs/Ge triple junction (TJ) solar mini-receivers immersed in white oils A/B/C, C14 n-alkane, C16 iso-alkane, and dimethyl silicone oil, respectively, is examined. A sizeable relative percentage increase (4.67–8.99%) in electrical conversion efficiency of TJ solar mini-receivers is found for 4-mm-thick liquid layers. Increasing the thicknesses of all the liquid candidates to approximately 9–10 mm continues to raise the efficiency of the corresponding TJ solar mini-receivers. The optical effect and the electrical effect contributing to the increase in efficiency, which is caused by the thin liquid layer on the solar cell front surface, are discussed. Further, to evaluate the durability of TJ solar mini-receivers operating in the examined liquids, UV exposure, damp heat, and step temperature accelerated lifetime tests on the liquid-immersed TJ solar mini-receivers were carried out. Results from the tests demonstrate the long-term stability of TJ solar mini-receivers operated in C14 n-alkane, C16 n-alkane and dimethyl silicone oil, respectively. They also indicate that among these the best liquids for immersing III–V concentrator solar cells is dimethyl silicone oil, followed by C14 n-alkane. [ABSTRACT FROM AUTHOR]

Concentrator solar cells that operate at high solar concentration level must be cooled. In this paper, direct liquid immersion cooling of triple-junction solar cells (InGaP/InGaAs/Ge) is proposed as a heat dissipation solution for dense-array high concentrating photovoltaic (HCPV) systems. The advantages of triple-junction CPV cells immersed in a circulating dielectric liquid and dish HCPV technology are integrated into a CPV system to improve the system electrical conversion efficiency. An analytical model for the direct liquid-immersed solar receiver with triple-junction CPV cells is presented. The main outputs of the model are the components temperatures of the receiver and the system electrical efficiency. The influence of concentration factor, mass flow rate, and inlet liquid temperature on the operating temperature of the triple-junction CPV cells and the system electrical conversion efficiency are discussed. It is shown that the system electrical conversion efficiency is very high for a wide range of operating conditions. The three operating parameters have a major effect on the operating temperature of the triple-junction CPV cells and, by extension, system output power. The flow rate selection should match concentration factor to keep the triple-junction CPV cells temperature lower and increase the electrical conversion efficiency of the dense-array HCPV system. [ABSTRACT FROM AUTHOR]

To solve the problem that solar cell temperature limits high-quality thermal output from a traditional concentrating PV/T (CPV/T) system, this paper proposes a linear CPV/T system with a vacuum tube receiver incorporated with a combined volumetric filter. In which a solid absorption glass along with liquid filter is used as the combined volumetric filter for the silicon CPV module. However, the entire photovoltaic/photothermal conversion process in the combined filtered CPV/T system is complicated. To achieve more accurate predicted performance, a three-dimensional numerical model of this system is presented and the combined Monte Carlo Ray-Tracing (MCRT) method with the Finite Volume Method (FVM) is employed. The stated optical models are validated against the experimental results from an indoor test under one sun. And the coupled method of MCRT and FVM is also verified. The optimal filter combination is obtained by optical simulation using LightTools software based on the MCRT method firstly. Then, the solar energy flux distribution on the receiver achieved from LightTools is adopted as a boundary condition for CFD simulation. Based on these models and the MCRT-FVM coupled method, parametric study is conducted to quantify optical efficiency, temperature distribution, energy and exergy efficiency of the system. The results show that the optimal combined filters for silicon PV module are HB700+water and HB700+propylene glycol (PG). Because the optical absorption of water differs from that of PG, the PV maximum temperature is 308.36 K using HB700+water and it is 321.94 K using HB700+PG, whereas the outlet temperature of water and PG exceeds 352 K. The greater thermal and total exergy efficiencies can be achieved at higher inlet temperature and lower mass flow rate, while the electrical exergy efficiency shows slight change. To further reduce heat loss, an indium tin oxide (ITO) coating with low emissivity is applied on the receiver surface. The results reveal the receiver with 240° ITO coating achieves the highest total exergy efficiency of 14.92% and optical efficiency of 88.94%. [ABSTRACT FROM AUTHOR]