In the context of the autonomous functioning of special equipment in the Far North and the Arctic is necessary to use its internal resources to maintain optimal thermal state units and units. This can be accomplished using a heat recovery system of the internal combustion engine. For this purpose the heat accumulator. The mathematical modeling of the thermal state of the heat accumulator in the cooling stage. The main factors affecting the cooling time of the thermal battery: TA insulation thickness, weight coolant, coolant temperature, air temperature, wind speed. Also developed a mathematical model of the process of cooling the heat accumulator in general terms. It is presented in graphical form, which simplifies the determination of the time of cooling the heat accumulator in its design. For the definition of Q and Bi developed a program «Time».

Keywords: operation, heat storage, thermal preparation, heat transfer, heat recovery system, low negative temperature