Thermodynamic analysis of heat transformers employing thermal sources and sinks of finite capacity

The problem of using low-level energies is a general one, in the light of the amount of thermal waste in numerous sectors. It is important both in the utilization of new energy sources available in thermal form (e.g., low enthalpy geothermal and solar energies) and in large-size works. Upgrading low-level energy can be achieved either by means of absorption and resorption cycles or by heat transformers or by their combinations. In this paper, after a definition of heat transformers, all the types of existing or thermodynamically possible heat transformers are considered by means of a suitable diagram; besides, the relative entropy production and the exergy efficiency, defined in another paper, are determined for various of the above devices operating with thermal sources and sinks of finite capacity. In addition, a new absorption heat transformer cycle using a partially miscible mixture is synthetically described.