Article discusses about the use of heat exchangers for stationary combustion engines and cogeneration units. The paper is dedicated to the problem of unused thermal energy in stationary engines. It analyses possibilities of accumulation of heat energy and its possible application in various fields. The paper deals with the classification of heat exchangers and with the subsequent description of design solutions of heat exchangers types used in given field. Resolves draft of exhaust gas heat exchanger according to the required parameters of internal combustion engine and subsequent simulation in the simulation program Comsol multiphysics to verify the correctness of the design and the construction solution of the exhaust gas heat exchanger for stationary combustion engines.