Solar collector with high working temperature and high efficiency for nonvacuum solar thermal power

Abstract

Currently, the technique of solar thermal utilization under high temperature in China is still in starting stage. The general nonvacuum tube solar collector and its components have disadvantages such as high emission rate, low absorption rate and low thermal efficiency under high temperature. This paper designed a kind of solar collector with high working temperature and high efficiency according to disadvantages in field of solar thermal utilization under high temperature. The collector could be used in nonvacuum solar thermal power system, and it could meet thermal conversion efficiency requirements of tower thermal condensation power system under high temperature. This design used Theminol VP1 heat transfer oil as thermal carrier and 625 special type alloys as collector tube material under high temperature. Selective absorbing coating was coated on surface of collector tube by thermal spraying. The collector tube was designed as internally ribbed tube with single flow array, and elbows were designed on both ends of the tube. Gaps between tubes are disposed by seal welding to form tube arrays, and the tube arrays were emplaced in cavity in upper part of solar collector tower, combined with reflection of mirror arrays emplaced on the ground to improve thermal collection efficiency, and to achieve higher thermal carrier temperature. The collector has simple structure, high thermal collecting efficiency under high temperature, and long service life. The collector could be used widely in areas such as solar thermal condensation power system, solar desiccation, solar cracking hydrogen production, and so on.