Reducing the energy consumption of the aerodynamic heating dryer

Abstract

A promising direction in the development of drying plants in the technologies of processing fruit and berry raw materials is the use of aerodynamic heating dryers. They implement the principle of transformation of electrical energy consumed to drive a centrifugal fan into thermal energy due to mutual friction of air flows circulating in a closed chamber. In this case, the overwhelming part of the electrical energy supplied to the rotor is spent on overcoming aerodynamic losses in the flow path of the impeller and in the drying chamber. To reduce the energy consumption of the drying process by reducing the energy consumption for heating the drying agent in the drying chamber, it is proposed to utilize the heat of the spent drying agent by equipping the dryer with a combined heat exchanger. It combines a plate heat exchanger and a solar air collector. The aim of the study was to analyze the efficiency of using a combined heat exchanger to reduce the energy consumption of an aerodynamic dryer when drying apples. The operation of the drying plant was investigated with and without a combined heat exchanger. To record the parameters of the drying agent, the environment, and the consumption of electric energy, an eight-channel TRM-138 thermoregulator meter with thermal resistance sensors and an electric energy meter with current transformers were used. An eight-channel TRM-138 thermoregulator meter with thermal resistance sensors and an electric en-ergy meter with current transformers was used to record the parameters of the drying agent, the en-vironment, and the consumption of electric energy. The research results showed that the use of a combined heat exchanger made it possible to increase the temperature of the drying agent entering the drying chamber by an average of 20 ºС relative to the ambient air temperature. A more intensive increase in the temperature of the drying agent when using a combined heat exchanger made it pos-sible to reduce the drying time by 3 hours. At the same time, electricity consumption decreased by 27.4%.