露点间接蒸发冷却器换热效能理论与性能实验对比

Theoretical and experimental analysis on heat transfer performance of dew point indirect evaporative cooler

为优化露点间接蒸发冷却器结构及不同工况环境下的冷却效率、风量配比与制冷量关系等工艺,对3种不同的露点间接蒸发冷却器(复合式、交叉式、逆流式)的技术原理、结构形式、传热传质特点进行对比分析,并在实验室模拟工况条件下对其湿球效率、露点效率、温降幅度、制冷量等性能进行测试。结果表明:干燥条件下这3种露点冷却器的湿球效率均可达到100%以上,露点效率在55%～85%之间;标准干燥工况条件(干球温度为38℃,湿球温度为23℃)下,交叉式和复合式露点冷却器的进出风平均干球温降在15℃左右,进出风平均湿球温降在5.5℃左右,明显优于复合式露点冷却器;逆流式露点冷却器的能效比为11.78左右,达到了最高的水准。

In view of the optimization of the dew point indirect evaporative cooler structure,the cooling efficiency under different environmental conditions,the relationship between the air volume ratio and the cooling capacity,and the technical principle,structure,heat and mass transfer characteristics of three different dew point indirect evaporative coolers(composite,cross and countercurrent)were compared and analyzed.At the same time,the three kinds of dew point indirect evaporative cooler were tested on the wet bulb efficiency,dew point efficiency,temperature drop range,cooling capacity and so on under the laboratory simulation conditions or practical applications.The experimental results show that under dry conditions,the wet bulb efficiency of the three dew point coolers can all reach above 100%,and the dew point efficiency is between 55%and 85%.In terms of the temperature drop range,the average dry-bulb temperature drop of the cross-type and composite dew-point coolers under standard drying conditions(dry bulb temperature of 38℃and wet bulb temperature of 23℃)is about 15℃,and wet bulb temperature drop is at about 5.5℃,significantly better than that of the composite dew point cooler.At this point,the countercurrent dew point cooler energy effciency ratio is 11.78,reaching the highest level.