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Indexed by:会议论文

Date of Publication:2009-01-01

Included Journals:CPCI-S

Page Number:670-677

Key Words:Solar energy; Flat-plate collector; High temperature circulating fluid; Numerical simulation; Thermal process

Abstract:The evacuated tube solar collector or concentrating systems are used normally in order to obtain higher temperature for the working fluid. But they have the shortcoming of extremely higher initial costs compared with the flat-plate collector (FPC). So the parallel flow flat-plate solar collector is commonly employed today for the collection of solar thermal energy, specially, for the low temperature solar thermal energy utilization. In this paper, the two-stage gas-liquid separated solar energy collector system for process steam production was developed. The thermal processes of flat-plate solar collector in the first circulation of the two-stage gas-liquid separated solar energy are investigated numerically. In this system, the high temperature working fluid R245fa is used to transfer the solar energy. Therefore, the FPC can be employed in this system to obtain satisfactory collector heat efficiency. The curves of temperature variation with time of each part of flat-plate solar collector and the working fluid have been obtained. It is found that the convection thermal loss must be considered firstly to study the thermal performance of solar collector with two glass covers. The variation of temperature with time of outer glass cover is very small, indicating which is very close to the ambient temperature. The temperature of inner glass cover increases to 61 degrees C with the increase of absorber plate temperature. And temperature of the working fluid will reach to evaporation state in shorter time after the solar collector start up.