This study investigates heat pump application to tobacco curing, using actual working condition with a mathematical model for heat pump. This mathematical model is written in MS Visual Basic 6.0 program. Heat pump is modeled to operate in 4 modes : ideal mode, actual mode without limitation to condenser temperature, ideal mode with limitation to condenser temperature and actual mode with limitation to condenser temperature. In each mode, there are 2 options, i.e., with and without heat recovery from exhaust air to be used at evaporator. It is found that the temperature difference between condenser and evaporator as well as the limitation of refrigerant properties were important factors on energy consumption in curing process using heat pump system. The coefficient of performance (COP) of heat pump system in yellowing and color fixing stage, leaf drying stage and stem drying stage were 5.55, 3.43 and 2.05, respectively. Operating mode with heat recovery from exhaust air can improve COP and reduce energy consumption in heat pump system for 16.5%. This study also found that curing tobacco with heat pump system required average specific energy consumption (SEC) of only 17 MJ/kg dry tobacco. This is less than SEC, required by central heat curing system about 50%. Unfortunately, electricity price is much higher than lignite. Therefore, the operating cost of heat pump system is higher than that of central heat curing system inevitably. For initial investment of heat pump system, it is 3 times more expensive than that of central heat curing system. Thus, heat pump system is less attractive for investment. However, considering the environment impact from tobacco curing with heat pump system, it can reduce emission released to atmosphere due to the fact that there is no combustion involved in heat pump system. Moreover, it was found that curing tobacco with heat pump system could relieve decomposition problem of fresh tobacco leaves from late curing.
