HEAT PUMPS AS AN ENERGY-EFFICIENT MEANS OF GRAIN DRYING

Abstract

Large energy costs for the process of drying grain crops associated with the increase in the price of energy carriers pose the task of reducing the energy component to the developers. The presented article focuses on the development of measures to reduce energy costs for the grain drying process using heat pumps. The considered advantages of heat pumps indicate the possibility of using these units for drying grain crops. Especially noteworthy is the increase in energy efficiency of heat pumps due to the conversion of ambient heat with a low temperature potential into heat with a high temperature potential. Thus, heat pumps are characterized by the heat pump conversion factor, which indicates their efficiency. The presented schemes with a heat pump implement the drying process in convective dryers, in particular in chamber, tunnel, shaft and drum dryers. Different schemes of heat pumps can be used for different types of dryers. The use of alternative drying sources for grain drying, in particular solar energy in the heat pump system, dramatically increases the efficiency of this installation. Also presented is a comprehensive scheme for the utilization of spent coolant in heat exchangers, an economizer, and a heat pump, which comprehensively addresses the issue of coolant utilization in a chamber dryer. In the drum dryer, the utilization of the spent coolant in heat exchangers and a heat pump is provided, increasing the temperature of the drying agent at the entrance to the dryer. For drying plant raw materials in a two-zone tunnel dryer, a heat pump scheme with two temperature levels of the heat carrier was developed for drying the material at different temperatures in the dryer zones.