A METHOD OF UTILISING LOW- AND MEDIUM-TEMPERATURE HEAT SOURCES AND MEDIA AND A SYSTEM FOR UTILISING LOW- AND MEDIUM-TEMPERATURE HEAT SOURCES AND MEDIA

摘要

The method of utilising low- and medium-temperature heat sources and media according to the invention is characterised by their use to preheat the working fluid in the lower cycle of a binary power plant comprising two working cycles thermally coupled with one another by at least one heat exchanger, whereas the working fluid in the lower cycle is a substance with a low evaporation enthalpy and a relatively high preheating enthalpy, preferably an organic fluid, while a high-temperature source of heat is used to preheat, evaporate and superheat the working fluid in the upper cycle. An organic fluid with the critical temperature higher, by 15 K - 20 K at best, than the temperature of the utilised heat source or medium is selected for the lower cycle. The system according to invention including two working cycles, is characterised by the connection of the preheater (10) of the lower cycle (6) to a flux of a low- or mid-temperature heat medium or source (16) from one or more sources, whereas the working fluid in the lower cycle is a substance with a low evaporation enthalpy and a relatively high preheating enthalpy, preferably an organic fluid, while the boiler (3) of the upper cycle is supplied with high- temperature heat. In another version of the invention, the system has the third cycle (9) with the lowest range of working temperatures, which is thermally coupled with the second working cycle (6) via a condenser/evaporator exchanger (8) or an exchanger of the condenser/evaporator- preheater (20) type.