TY JOUR TI RESEARCH OF GEOTHERMAL HEAT PUMP UNIT EFFICIENCY IN CLIMATIC CONDITIONS OF RUSSIAN REGIONS KW heat pump KW heating KW temperature schedule KW quality control KW coefficient of transformation KW COP JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Trubaev, P.A. AU Koshlich, Y.A. AU Belousov, A.V. AU Buhanov, D.G. AU Grebenik, A.G. AU Prasol, D.A. PY 2025 IS 10 PB Belgorod State Technological University named after V.G. Shukhov