Mushroom drying with solar assisted heat pump system

Abstract

In this study, a simple and cost effective solar assisted heat pump system (SAHP) with flat plate collectors and a water source heat pump has been proposed. Mushroom drying was examined experimentally in the drying system. Solar energy (SE) system and heat pump (HP) system can be used separately or together. A computer program has been developed for the system. Drying air temperature, relative humidity, weight of product values, etc. were monitored and controlled with different scenarios by using PLC. This system is cheap, good quality and sustainable and it is modeled for good quality product and increased efficiency. Thus, products could be dried with less energy input and more controlled conditions. Mushrooms were dried at 45°C and 55°C drying air temperature and 310kg/h mass flow rate. Mushrooms were dried from initial moisture content 13.24gwater/gdrymatter (dry basis) to final moisture content 0.07gwater/gdrymatter (dry basis). Mushrooms were dried by using HP system, SE system and SAHP system respectively at 250–220min, at 270–165min and at 230–190min. The coefficients of performance of system (COP) are calculated in a range from 2.1 to 3.1 with respect to the results of experiments. The energy utilization ratios (EURs) were found to vary between 0.42 and 0.66. Specific moisture extraction rate (SMER) values were found to vary between 0.26 and 0.92kg/kWh.