An Experimental Study on a Novel Heat Pipe-Type Photovoltaic/Thermal System with and without a Glass Cover

A novel heat pipe-type PV/T system was designed and constructed in the present study to solve the freezing problem associated with the traditional photovoltaic/thermal (PV/T) system. Outdoor tests were carried out from May to July 2010. The performances of the system with and without glass cover were also studied. The results showed that the average photothermal efficiency with glass cover was 41.30%, which was a little higher than that of the unglazed condition at 37.16%. However, the result of the tests on photoelectric efficiency was the opposite. The average efficiency was 9.42% with glass cover, which was lower than that without the glass cover at 11.51%. The unglazed condition efficiency curve showed a big fluctuation, whereas the glazed condition was almost a perfect parabola. The average first law efficiency of the glass-covered system was 48.52% compared with 44.24% without the glass cover. Conversely, the glass-covered system had a second law efficiency of 6.87%, which was lower than that of the unglazed condition at 8.01%.