In order to recover the exhaust-heat of a drier including latent-heat and utilize it for heating the inlet-air, a practical scale drying system with a heat pump was designed and the performance of the heat pump were tested.
    Experimental apparastus is composed of heat pump system with compressor, evaporator, condenser and air circulated system with ducts(diameter:250mm), drying chamber(700 x 1200 x 1200mm) and blower.
    As the results of heat-pump performance test, the evaporator had a capacity absorbing heat of 4000-5900 kcal/h and the drying system can deliver a warm air of temperature 50-60 centigrade, relative humidity 14-26% to the drying chamber. The coefficient of performance of the heat pump was about 4-5.