分段式二级热泵干燥系统数值模拟研究

Numerical Simulation Research on Segmented Two-stage Heat Pump Drying System

传统热泵干燥系统难以充分回收干燥排湿废气的热量,且热泵机组制热效率有待提高。本文以分段式二级热泵干燥系统为研究对象,构建系统仿真模型,基于数值模拟的方法迭代计算制冷工质与干燥空气处于热、质平衡时的各级热泵的蒸发温度与冷凝温度,并分析干燥排湿废气对二级热泵机组能量回收及除湿特性的影响,研究蒸发与冷凝近连续变温过程的干燥能效。结果表明:当排湿废气温度为25~30℃、相对湿度为85%,循环风量为1,000~2,500 m^3/h,目标送风温度为65℃时,二级热泵干燥系统性能系数(COP)最大值为3.1,除湿能耗比(SMER)最大值为2.0 kg/(kW·h)。

It is difficult for the traditional heat pump drying system to fully recover the heat of the dry exhaust gas,and the heating efficiency of the heat pump unit needs to be improved.In this paper,a segmented two-stage heat pump drying system is taken as the research object and a system simulation model is built,based on the method of numerical simulation,the evaporation temperature and condensation temperature of two heat pumps are iteratively calculated when the refrigerant and dry air are in heat and mass balance,and the effect of drying and exhaust moisture on the energy recovery and dehumidification characteristics of the two-stage heat pump unit is analyzed,and the drying energy efficiency of evaporation and condensation in a nearly continuous temperature change process is studied.The results show that when the temperature of the exhaust gas is 25-30℃,the relative humidity is 85%,the circulating air volume is 1,000-2,500 m^3/h,and the target air temperature is 65℃,the maximum of coefficient of performance(COP)is 3.1,and the maximum of specific moisture extraction rate(SMER)is 2.0 kg/(kW·h).