蜂窝热管平板式太阳能热水器的研究

【作者】 施慧烈；

【导师】 胡亚才； 王建平；

【作者基本信息】 浙江大学 ， 工程热物理， 2002， 硕士

【摘要】 本文研究设计了一种新型的蜂窝热管平板式太阳能热水器，其特点是同时应用了热管技术和蜂窝技术的平板式太阳能热水器。首先分析了目前国内太阳能热水器现状及它们的优缺点以及今后的发展趋势，在此基础上提出了本文的研究课题。本研究中用到的热管是重力热管。重力热管具有热二极管特性，并且具有较强的传热能力和较高的等温性，这使得热管在太阳能的热利用中得到应用。而在透明玻璃盖板和吸热板之间放置蜂窝结构，基本上能消除吸收表面和盖板之间的空气自然对流热损失，并可大大降低辐射损失，显著提高集热器的热转换效率。 通过大量的实验，对蜂窝热管平板式太阳能热水器和全玻璃真空管式太阳能热水器的热性能进行比较，包括瞬时效率、日平均效率、热损系数等。蜂窝热管平板式太阳能热水器的非稳态效率曲线是一条负斜率的直线，而全玻璃真空管式太阳能热水器的非稳态效率曲线是一条先下降后上升的曲线。蜂窝热管平板式太阳能热水器在低温的情况下(一般小于60℃)具有优势，其日平均效率为48.3％，而真空管式太阳能热水器的日平均效率为42.2％。高温段(一般大于60℃)的时候，平板式太阳能热水器日平均效率比真空管式太阳能热水器日平均效率低。这主要是由于在温度较高的时候，平板式太阳能热水器的热量损失比真空管式太阳能热水器热量损失的大，另外两者吸热体形状也不相同，平板式太阳能热水器的接收为一平面，而真空管式太阳能热水器的接收表面是圆柱面，所以平板式太阳能热水器日平均效率为29.8％，而真空管式太阳能热水器日平均效率为35％。蜂窝热管平板式太阳能热水器晚上的热损系数比真空管式太阳能热水器小很多，为1.16，而真空管式热水器为2.24，这进一步从实验上证明了太阳能热水器应用热管和蜂窝后使得热水器的集热性能和保温性能得到了提高。 在对蜂窝热管平板式太阳能热水器用丙酮热管和水热管的对比中得出，热管的性能对太阳能热水器的性能有很大的影响，由于此次实验中丙酮热管做的比水热管差，因此丙酮热管的热阻比水热管大，这在一定程度上影响了热水器的热性能。 同时建立了蜂窝热管平板式太阳能热水器的理论传热模型，通过对实验值和理论值的比较，得出进行简化后的理论模型在一般情况下与实际的情况是符合的，因此可以用理论计算公式对蜂窝热管平板式太阳能热水器的热性能进行估算。更多还原

【Abstract】 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.更多还原