Development of a Mathematical Model for Heat Pump Fruit Drying

Abstract

A mathematical model for papaya glacé drying using heat pump has been developed. It comprises of drying rate equation, mass and energy balance equations, thermo-physical property of papaya glacé equations and heat exchanger equations. Successive substitution method was used for finding the solution. It was found that the model was fairly accurate for predicting final moisture content, air temperature at various parts in the system and temperature of refrigerant especially at low moisture level of papaya glacé. The mathematical model was then used to find out strategy for drying papaya glacé with a specific air flow rate of 29.8 kg/h-kg dry papaya glacé. Simulated results showed that drying time and energy consumption was decreased when the drying air temperature was increased. In addition, the appropriate bypass air ratio was in the range of 86-90 %.