DISTRICT ENERGY DISTRIBUTING SYSTEM AND METHOD OF PROVIDING MECHANICAL WORK AND HEATING HEAT TRANSFER FLUID OF A DISTRICT THERMAL ENERGY CIRCUIT

摘要

A district energy distributing system comprising a geothermal power plant (50) comprising a first and a second circuit is disclosed. The first circuit comprises a feed conduit (11) for an incoming flow of geothermally heated water from a geothermal heat source (10); a boiler (51) comprising a heat exchanger (52a, 52b, 52c) configured to exchange heat from the incoming flow of geothermally heated water to superheat a working medium of a second circuit of the geothermal power plant (50); and a return conduit (12) for a return flow of cooled water from the boiler (51) to the geothermal heat source (10). The second circuit comprises the boiler (51) configured to superheat the working medium of the second circuit; an expander (53) configured to allow the superheated working medium to expand and to transform the expansion to mechanical work; and a condenser (55) configured to transform the expanded working medium to liquid phase and to heat a heat transfer fluid of a district thermal energy circuit (20). The district thermal energy circuit (20) comprises a plurality of local heating systems (200; 250), each system (200; 250) being configured to provide hot water and/or comfort heating to a building (40). The condenser (55) is configured to heat heat transfer fluid of the district feed conduit (22) to a temperature of 5-30°C. Also, a method of providing mechanical work and of heating heat transfer fluid of a district thermal energy circuit (20) is disclosed.