Design and Thermal Analysis of an Air Source Heat Pump Dryer for Food Drying

In this study, an experimental heat pump dryer was designed. The specific moisture extraction rate and moisture extraction rate were used as performance indicators to explore the influence of environmental factors and the style of the hot air cycle on heat pump drying. The average temperature and humidity in Nanjing’s summer, winter, and throughout the whole year were taken as the experimental ambient temperature and humidity. Garlic slices 3 mm thick, with an initial moisture content of 66.714% w.b., were dried until the end moisture content was 10% w.b. Experimental results and thermal analysis showed that the open and semi-open heat pump dryers were greatly affected by ambient temperature and humidity. The closed heat pump drying system was greatly affected by the bypass air rate.