ANALYSIS OF HOP DRYER PERFORMANCE WITH PARTIAL THERMAL ENERGY RECOVERY

Drying is an integral part of the technological process of commercial hop production. Depending on the production volume and the level of automation of the process, there are several ways to dry hop cones, including convective, microwave and sublimation. At the same time, dryers have different ratios of quality and productivity. Reducing energy costs for drying hops is an important area in the development of hop growing. In this regard, modernization and analysis of the productivity of hop dryers is a pressing issue in the current conditions of rising production costs. The aim of the research is to analyze the productivity of the MXS-25 hop dryer, modernized by installing a heat pump in the air circulation circuit and having adjustable heat recovery. The air temperature in the drying chamber was successfully controlled in the range of 60 ± 2 ° C. The preheating time required to achieve the air temperature was approximately 0.5 hours, which corresponds to approximately 5% of the total hop drying time. Comparison of the measured and calculated energy consumption values showed that the experimental values were in the range of 10.2 kWh to 11.5 kWh, averaging approximately 10.85 kWh during the experiment. Accordingly, the calculated values were in the range of 8.9 kWh and 10.2 kWh, averaging 9.55 kWh. A series of experiments comparing the drying performance using partial recovery showed that with an increase in the ambient temperature to 24 °C, the maximum relative moisture separation rate reached 6.23 kg/(kWh) with a bypass ratio of 0.86, which was higher than that of 5.54 kg/(kWh) for drying with full recovery. The partial heat recovery system is superior to the full recovery system in terms of energy efficiency and increased hop drying performance.