Thermal performance test of U-type evacuated glass tubular solar collector filled with graphite

In this paper, a new type of U-type pile evacuated glass tubular solar collector filled with graphite has been proposed and investigated its thermal performance experimentally, and testing accuracy has been analyzed by the error analysis method. Following dynamic testing method, the outlet temperature and momentary efficiency equation of the collector were got. The results showed that, U-tubular evacuated tube has higher momentary efficiency, the outlet temperature can increase 6~7°C in test situation, the optimum flow rate of U-type evacuated tubular is 0.0028L/s.