This master’s thesis deals with the possibility of increasing efficiency of energy blocks with combustion engines by the combination of the Sabat and Clausius-Rankine cycle into the combined cycle. In the thesis is briefly described the principle of the function of the auxiliary device, which can increase the efficiency of the combustion engine. This device, which consists of a waste heat boiler and two turbine modules, is designed using calculations. Both turbine modules are prepared with drawing documentation and there are described important structural elements. Each key part of the thesis is given by a brief theory, so the basic theory of combustion engines, waste heat boilers and steam turbine are described