Harvesting potatoes and vegetable crops coincides with the seasonal peak of precipitation. As a result, the factor complicates the cleaning of marketable products from highly humid soil impurities, which cause the working surface sticking of cleaning devices and decrease their performance. To eliminate this problem, the authors carried out theoretical studies of the separation system working on thermal energy for cleaning the exhaust gases of the power plant. The goal was to determine the design and technological parameters of its individual functioning elements. Relationships were established to determine the separating surface area of slotted cleaning units – a bar elevator and a cleaning sprocket. The analysis helped determine the inter-axial distance between the deflectors, the inter-deflector distance, the inter-conveyor distance, and the translational speed of the rod elevator. The authors obtained the heat flow distribution pattern of exhaust gases on the separating units of root crop and potato harvesters. The study outcomes – the operating modes and technological parameters of the separating system using the heat of exhaust gases for harvesting root crops and potatoes and the heat flow distribution pattern of exhaust gases over the separating surface – will be helpful for further experimental research to improve individual units for harvesting root crops.