Thermal performance analysis of large-scale flat plate solar collectors and regional applicability in China

Abstract

The thermal performance of flat-plate solar collectors (FPSCs) depends not only on environmental and operational parameters but also on its dimensions. In this study, the thermal performance improvement mechanism of FPSCs is studied focusing on the impact of collector size. Numerical simulation models for both large-scale flat-plate solar collectors (LSFPSCs), and conventional FPSCs in parallel, are introduced. The relationship between thermal performance and collector dimensions is studied for the LSFPSCs. Furthermore, the effect of the environmental and operational parameters on the thermal performance of the two collector types is investigated. Moreover, the applicability of LSFPSCs in China is analyzed with respect to available operating times, useful energy, and heat loss. The results indicate that increasing the collector dimensions can improve the thermal performance of FPSCs effectively, and the LSFPSCs perform better than conventional FPSCs in parallel. Compared to the conventional FPSCs, the collector efficiency of the LSFPSCs is higher-especially for low solar irradiance, low ambient temperatures, and high mass-flow rates. In addition, the LSFPSCs excel in solar-energy rich areas, the available daily operating time in Lhasa is 9.6 h, which is the longest operating time among the studied cities, and the proportion of useful energy is about 55 %.