Low-Temperature Heat-Driven Compression Refrigeration Machines with R744

In the paper, the principle for developing the cycles and schematics of low-temperature heat-driven compression refrig- eration machines with R 744 as the working fluid is presented. Such a machine is formed by the combination of the two thermodynamic cycles: direct (heat engine) and inverse (refrigeration machine). The mechanical work obtained from the direct cycle is transmitted for the realization of the compression process within the inverse cycle. The thermodynam- ic processes are taking place: within direct cycle in the supercritical zone, within inverse cycle in the supercritical and two-phase zones. The schematics of the machines were developed at condition to generate cold at the temperature level -50 оС taking into account the reliability during the operation. The energetic effectiveness has been determined.