The article deals with effective use of low-temperature exhaust heat. The method is that direct thermodynamic cycle with water and alternative working fluids can be used. With direct thermodynamic cycle expansion engine should be used to obtain some additional energy in electrical generator. At electrical power plants turbines with blades are usually used as an expansion device for water vapor. When expansion engine is brought into circuit design with compressor station the following parameters are used for calculations: t0, working fluid boiling temperature in direct cycle, = 100 оС, working fluid condensation temperature tк = 50 оС. In calculations for gas-turbine unit: boiling temperature t0 = 117.8 оС, condensation temperature tк = 50 оС. Water and the following halocarbons are considered as working fluids: R600, R11, R21, R113, R114, R123. The choice is made according to the following parameters: upstream pressure is not more than 2 МPа due to general requirements to refrigeration equipment, downstream pressure is no less than 0.1 МPа due to no outdoor air inflow, working fluid expansion ratio limit  is not more than π = 15.