Cellular Heat Pipe Flat Plate Solar Water Heater

In the paper, a flat plate solar water heater of honeycomb and heat pipe (abbreviated as HHCHP) is studied and designed. Its characteristic is that it is a flat plate solar water heater applying heat pipe technology and honeycomb technology simultaneously. At fist, actuality and development of solar water heater at domestic are analyzed and then researching contents are put forward. In the design, heat pipe is gravity heat pipe. A gravity heat pipe possesses heat diode characteristics and excellent transfer heat ability and equality temperature characteristics. The above features enable gravity heat pipes to use in the field of solar heat. Between glass-cover board and endothermic board, honeycomb is placed, which can eliminate heat loss caused by air natural convection and greatly reduce heat loss caused by radiation, and hence a better transfer heat efficiency.Through experimentation, we compare the heat performance of HHCHP with that of a 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. The instantaneous efficiency curve of HHCHP is a negative slope beeline, while that of HGVT isn't. On condition of low temperature, commonly below 60℃, the average efficiency of HHCHP is 48.3%, while that of HGVT is 42.2%. On condition of high temperature, commonly above 60℃, the average efficiency of HHCHP is 29.8%, while that of HGVT is 35%. The heat loss of HHCHP being much less than that of HGVT at night, then the heat loss coefficient of HHCHP is 1.16, while that of HGVT is 2.24. The preceding comparisons prove that collecting heat efficiency and heat preservation performance are improved because of simultaneous application of heat pipe technology and honeycomb technology.Copper-acetone heat pipe and copper-water heat pipe of solar water heater compared, we also find in the experimentation that the performance of heat pipe greatly affects the heat performance of solar water heaters. In the experiment, the heatresistance of copper-acetone heat pipe was more than that of copper-water heat pipe.In the paper, theoretic transfer heat model of HHCHP is established. After comparing experimental value and estimative value, we deduce that theoretic transfer heat model accords with actual condition, so we can estimate the heat performance of HHCHP by theoretic calculation formula.