PERFORMANCE OF A HEAT-PUMP ASSISTED DRYER

We present a simple mathematical model of a heat-pump-assisted dryer d eveloped from psychrometric processes. A term 'contact factor' is used in the theoretical model to characterize the drying chamber. The expe rimental data of the drying rates of different types of products are u sed to predict the values of the contact factor of the dryers. We exam ine the effect of various parameters such as the contact factor, air i nlet conditions, and the moisture removal rate on the performance of t he heat-pump-assisted dryer. It has been shown that the non dimensiona l contact factor of a dryer is insensitive to dryer air inlet temperat ure. Finally, a performance chart to guide the selection of the heat-p ump dryer components is proposed.