Modernization of the heat pump installation for drying wheat

Abstract

The most energy-consuming and most critical stage of post-harvest processing is grain drying. Safety of grain depends on its drying. For drying grain, grain drying plants are used that remove excess moisture from the grain. In most cases, drying occurs under the influence of elevated temperatures with a constant supply of heat. After drying, the grain must be cooled to eliminate irreversible processes. The drying process is slow due to temperature limitations. To speed up the drying process, various techniques are used, one of which is the alternation of heating and cooling processes (differentiation of heat input). To increase the drying energy efficiency in the conditions of differentiation of the supply of thermal energy, it is advisable to use heat pump units. Heat pump units allow the creation of a heating agent (heated air) and a cooling agent (cooled air). Studies have shown that for different grain parameters, different temperature characteristics of heating and cooling agents are required. For independent temperature control of heating and cooling agents, an original design of a heat pump installation has been developed. To automate the control of the drying process, several control schemes have been developed and investigated.