相变蓄热U型真空管太阳能集热器热性能研究
THERMAL PERFORMANCE OF U-PIPE EVACUATED TUBE SOLAR COLLECTOR WITH LATENT HEAT THERMAL ENERGY STORAGE
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摘要: 建立相变蓄热U型真空管太阳能集热器三维传热数值计算模型,研究工质流动时相变材料对U型真空管集热器热性能的影响,与无相变U型真空管集热器进行对比,探讨相变材料主要物性参数和工质质量流量对其热性能的影响规律。结果表明,在U型真空管集热器中填充相变材料可有效降低U型真空管集热器的出口温度峰值,相变材料在夜间及太阳辐射较弱时释放热量,延长了集热器的有效运行时间,相变集热器与传统无相变集热器的有效集热量相差较小。与无相变集热器相比,相变集热器出口温度峰值最大降低了10.6 K,有效运行时间延长了1.0～3.7 h。Abstract: A three-dimensional heat transfer model of U-pipe evacuated tube solar collector with phase change material（PCM） is established.The influence of PCM on the thermal performance of U-pipe evacuated tube collector is studied with working fluid flowing,the comparison of thermal performance of U-pipe evacuated tube collector with and without PCM is made,and the influence of the main physical parameters of PCM and the mass flow rate of working fluid on the thermal performance of solar collector is discussed.The results show that the peak outlet temperature of U-pipe evacuated tube collector is reduced effectively with PCM.Heat is discharged by PCM when solar radiation is weak and at night,and the operating time of solar collector is extended.The difference of effective heat gains of solar collector with and without PCM is very small.Compared to that of solar collector without PCM,the peak outlet temperature of the solar collector with PCM is reduced by 10.6 K,and the operating time is extended by 1-3.7 h.
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