多模式再生运行的热源塔热泵系统运行能效分析

OPERATION EFFICIENCY PERFORMANCE OF MULTI-MODE REGENERATION HEATING TOWER HEAT PUMP SYSTEM

针对常规建筑空调冷热源形式的不足之处,采用多模式再生系统改善常规热源塔热泵系统,详述其工作原理、工作模式和系统设计方法。在实际节能改造项目中应用该系统并给出控制策略与评价计算方法,对制冷、制热和吸湿的典型工况进行现场实际测试,结果表明:在该系统设计参数下,夏季平均空气温度28.6℃、平均相对湿度84.5%工况综合制冷效率为4.51,冬季平均空气温度7.68℃、平均相对湿度81.2%工况考虑再生能耗在内综合制热效率为3.46。系统运行过程中溶液吸湿量与环境温度和相对湿度有关,环境温度越高,相对湿度越低,吸湿量越小。热源塔吸热由显热和潜热两部分组成,潜热占比受运行过程吸湿量影响,与空气相对湿度直接强相关,相对湿度越低,空气与水接触面水蒸气分压力差越小,水分更难从空气迁移到溶液中。测试时间内平均相对湿度81.2%的工况下由溶液吸湿导致的潜热占总系统热量比例约为18.6%。再生机组再生效率高低受外界环境与工况变化的影响较小,5天内平均值为4.45 kg/kWh。

To address the inadequacies of traditional building air conditioning systems’cooling and heating sources,this study employs a multi-mode regeneration heating tower heat pump system and discusses its operating principle and mode in detail.The novel system is used in an actual energy-saving transformation project,and the control strategy and calculation techniques for assessment are provided.The results of field tests conducted under normal operating circumstances of refrigeration in the summer and heating in the winter reveal that in summer,the average comprehensive cooling efficiency is 4.34 with an average air temperature of 28.6℃and an average relative humidity of 84.5%.At an average ambient temperature of 7.68℃and an average relative humidity of 81.2%,the average comprehensive heating efficiency is 3.46.The moisture absorption of the solution during system operation is related to the ambient temperature and relative humidity.The moisture absorption keeps a smaller amount at a higher ambient temperature and lower relative humidity.The heat absorption of heating tower is composed of sensible heat and latent heat.The proportion of latent heat is affected by the moisture absorption during operation and strongly related to the relative humidity of the air.The lower the relative humidity,the smaller the differential pressure of water vapor on the air-water contact surface,and the more difficult it is for water to migrate from the air to the solution.Under the test conditions of 81.2%relative humidity during the test time,the latent heat caused by moisture absorption accounts for approximately 11.5 percent.With changes in the external environment and working conditions,the regeneration efficiency of the regeneration unit remains relatively stable,with an average value of 4.45 kg/kWh within 5 days.