Author：Li-Duhng Huarng¹, Hsiang-Wen Chiu², Jyh-Rong Tsay³, Jian-Jhih Lin²

¹ Senior Agricultural Engineer, Taiwan Agricultural Research Institute, COA
² Assistant Agricultural Engineer, Taiwan Agricultural Research Institute, COA
³ Senior Agricultural Engineer & Secretary General, Taiwan Agricultural Research Institute, COA

Abstract：

    As the energy prices continued to hike internationally, saving energy and improving efficiency have become the focus issue. Heat pumps absorb heat in the ambient air or water through the evaporation, compression and expansion process of the Rankine cycle that transfers the heat energy in an opposite direction of spontaneous heat flow. The system is energy efficient and saves a lot of energy. The application of heat pumps has become a hot tool to replace the diesel or gas burner in order to save energy costs effectively.

    The operation of a heat pump system generates both heat and cold simultaneously; therefore, it provides high energy efficiency. According to the source and destination of the heat, the heat pumps can be categorized into air-water heat pumps and water-water heat pumps. A water-water heat pump system was adopted in this study. The application of its hot air in drying agricultural products and cold air in condensing water vapor generated in the drying process allows agricultural products using this drying method showing good color. In addition to improve the drying quality of agricultural products, it also promotes energy efficiency. It is an effective way to save energy and reduce carbon emission. The heat pump condensing dryer set up in TARI can provide 65℃ hot air for drying through the heat exchanger and the cold water temperature reaches as low as 12℃. The total energy efficiency of the system (COP) is above 3.6.

Keywords: Heat pump, Condensation drying, Coefficient of performance.