Vacuum Glass Cover Theoretical And Experimental Study Of Heat Pipe Solar Water Heater

Flat plate solar water heater of vacuum glass-cover board and heat pipe(abbreviated as HVGHP) is a new solar energy gather device of our invention. In the paper, the heat performance of HVGHP is studied. At first, actuality and development of solar water heater at domestic are analyzed and the development of our country' s solar water heater industry are reviewed. Then the researching contents are put forward.The distinguishing feature of HVGHP is applying vacuum glass technology and heat pipe technology. A gravity heat pipe possesses heat diode characteristics and excellent transfer heat ability and equality temperature characteristics. And a vacuum glass-cover board can greatly reduce heat loss caused by surface convection, and hence a better transfer efficiency.Through experimentation, we compare the heat performance of HVGHP , the flat plate solar water of honeycomb and heat pipe (abbreviated as), and the solar water heater of glass vacuum tube (abbreviated as HGVT). The heat performance of a solar water heater includes instantaneous efficiency, average heat efficiency and heat loss coefficient. At low temperature (between 30C and 60C), the average heat efficiency of'HHCHP is 0. 525, that of HVGHP is 0. 537, and that of HGVT is 0. 456. We can see that the average heat efficiency of HVGHP is higher than that of HHCHP and HGVT. At high temperature(between 60C and 90C), the average heat efficiency of HHCHP is 0. 306, that of HVGHP is 0. 348, and that of HGVT is 0. 325. We can see that the average heat efficiency of HVGHP is higher than that of HGVT and that of HGVT is higher than that of HHCHP.At low temperature (between 30C and 60 C), the heat loss coefficient of HHCHP is 1. 11, that of HVGHP is 0.93, and that of HGVT is 1.64. Wecan see that the heat loss coefficient of HVGHP is higher than that of HHCHP and HGVT. At high temperature (between 60C and 90C), the heat loss coefficient of HHCHP is 1.45, that of HVGHP is 1.08, and that of HGVT is 2.59.We can see that whatever at low temperature or at high temperature, the the heat loss coefficient of HVGHP is lower than that of HGVT and that of HHCHP. Hence the experimentation proved that the heat performance of HVGHP is greatly improved by applying vacuum glass technology and heat pipe technology.