Heat pump drying : use of ambient air as enery source for cooling

The concept of heat pump drying was investigated on the example of an industrial system for clipfish by a dynamic object-oriented model approach. The climatic conditions at the production facility are considered as additional energy source for the de-humidification of the drying air. The annual saving by installing an extra heat exchanger between ambient air and the drying agent reduced the energy demand by around 33%. During the winter season the heat pump drying system was only required for heating of the drying air, which resulted in a better usage of the excess energy. During summer season the temperature of the ambient air was too high to substitute the heat pump. The potential for the usage of ambient air as cooling energy source in heat pump drying will be limited by the temperature requirements of the drying process and seasonal variations.