HienResearch on the operation mode of heat pump drying machine with drying experiments of scallions for saving energy

Abstract

This paper provided many drying experiments of scallions at different drying modes through controlling the drying air temperature from 30°C to 40°C and the drying air velocity> after drying chamber from 0,5 to 1,5m/s for determining the operating mode of the heat pump drying machine. Fiom in the results of many drying experiments of scallions, we have compared and checked the feasibility of the heat pump drying machine, the energy efficiency and the quality of dried product. In the drying mode, the drying air temperature is 40°C and the drying air velocity after drying chamber is 1 .Om/s, the scallions drying product has the quality of natural light green color delicious taste, vitamin content C contains 14.2mg/kg higher than hot air drying method (vitamin C content of 13.8mg/kg), solar drying method (vitamin C content of 11.7mg/kg) and the drying time shortest 9 hours.