This article describes application of the thermocompressor with the cold chamber temperature equal to temperature of liquid natural gas. The main distinctive feature of this device is an ability to increase pressure without compression of working fluid. It is possible by isochoric heating and refrigeration in  thermocompressor. Power is required for overcoming friction. Also this article deals with advantages and disadvantages of the thermocompressor. Mathematical model was created with account for reality of working fluid situated in the cold chamber and regenerator. Thermocompressor’s capacity relative to frequency and temperatures was plotted. Analysis of this dependencies was carried out, and the optimum of frequency was determined. Appraise of the thermocompressor’s application with liquid natural gas was made.