Experimental investigation on a solar assisted heat pump in-store drying system

Solar powered drying is an environment-friendly technique utilized to dry grain. A novel in-store drying system composed of flat-plate air collectors, a heat pump, fans, air ducts, and grain stirrer is proposed to make full use of solar energy and to reduce the consumption of electricity. A demonstration system was built and tested in Kunming, China. The experimental data was compared with the results derived from a mathematical simulation. The experimental and simulated data demonstrate that the solar assisted heat pump drying system improved the performance of the in-store drying process. An average temperature rise of 8.9 °C for the granary inlet air was achieved. The drying rate was increased and the uniformity of grain moisture content was improved. In addition, the grain was maintained in good quality and the level of power consumption was reduced.

► A novel in-store drying system using solar energy and heat pump. ► A demonstration project was built and tested. ► The experimental data was compared with the mathematical simulation. ► An average temperature rise of 8.9 °C for the granary inlet air was achieved. ► Grain was maintained in good quality and energy consumption was reduced.