The compression heat-using refrigerating machines operating in the Chistiakov-Plotnikov cycle use recycled waste heat of power machines as primary energy for producing cold of various temperature potentials thus saving fuel and energy resources. Development and improvement of machines is associated with the use of new working fluids. A selecting method of working fluids for a machine with a block «turbine-compressor» was proposed from the standpoints of such fundamental characteristics as energy saving and environmental safety. Mutual influence of properties of R134a, R290, R401a, R410a, R407a, R507, R600, R717 working fluids and design values of the block «turbine-compressor» in the given temperature regime of the thermodynamic cycle were studied with observance of equality of turbine and compressor powers. Design values of the full-size block «turbine-compressor» sample and the results of its experimental studies with the use of previous working fluids were used for the study. The method of selection of the working fluids for the cold supply system of a particular consumer (a fruit storage) equipped with a small power machine was demonstrated on a particular example for a given temperature regime of cold production and the design values of the block. Introduction of the dimensionless equilibrium criterion in the analysis has made it possible to establish and evaluate dependence of the block design values on thermodynamic properties of the working fluids and conditions of its work and the field of rational application of any working fluids for a particular block design. The compression heat-using refrigerating machine is capable of efficient cold production with the studied working fluids in the trigeneration system of a small power machine.