Review on low-temperature heat pump drying applications in food industry: Cooling with dehumidification drying method

Abstract

Moisture content of food material is a key factor influencing the quality of storage and extending the quality of a food product. Manufacturers develop new technologies to process sensitive food materials to supply new products with improved properties and high quality. The process in which the air is cooled sensibly while the moisture is removed from food is called cooling with dehumidification process. The system fundamentally acts as a heat pump, which pumps the heat from the dehumidified air to a different air stream in another area, with the aid of a refrigerant gas to carry the heat. This article reviews the potential of low-temperature heat pump dehumidifier drying used in the food industry. Moreover, this describes the principle of cooling with dehumidification (CWD) process, the importance of studying psychrometric charts to understand CWD process, measures used in identify energy efficiency, comparison of this method over common dryers, applications, advantages and limitations of the CWD drying method.