Experimental Study on Temperature Lifting of Heat Pump System at Initial Drying Stage

Abstract

In order to increase drying rate at initial stage, the heat pump drying systems often lift temperature of the drying air assisted with electrical heating. However, power consumption of drying systems is raised. By taking advantage of an auxiliary evaporator and adjusting its fluid fluxes, the heat pump drying systems can acquire the same results of lifting temperature as those assisted with electrical heating. Experiment results demonstrate that the heat pump unit with an auxiliary evaporator is able to not only lift temperature quickly at initial drying stage, but also enhance the material dehumidification obviously when drying temperature ranges from 40°C to 55°C.