A district energy distributing system is disclosed. The system comprises a geothermal heat source system comprising a geothermal heat source and a feed conduit for a flow of geothermally heated water from the geothermal heat source. The system further comprises a district feed conduit, a district return conduit and a plurality of local heating systems, each having an inlet connected to the district feed conduit and an outlet connected to the district return conduit, wherein each local heating system is configured to provide hot water and/or comfort heating to a building, A central heat exchanger is connected to the feed conduit of the geothermal heat source system such that an incoming flow of geothermally heated water is provided to the central heat exchanger.

A geothermal power plant and method of operating a geothermal power plant in which control over the creation and growth of fractures in the geothermal formation is achieved. A downhole pressure gauge (14) with a high data acquisition rate is located in the injection or production well. Pressure changes in the well are recorded as a pressure trace and transmitted to the surface as data. The data is analysed to determine fracture parameters of the geothermal formation. The pump rate of the well is then varied in response to the calculated fracture parameter(s).

A geothermal power plant and method of operating a geothermal power plant in which control over the creation and growth of fractures in the geothermal formation is achieved. A downhole pressure gauge (14) with a high data acquisition rate is located in the injection or production well. Pressure changes in the well are recorded as a pressure trace and transmitted to the surface as data. The data is analysed to determine fracture parameters of the geothermal formation. The pump rate of the well is then varied in response to the calculated fracture parameter(s).

A geothermal heat mining system can operate within a single primary borehole in a geothermal reservoir. A primary fluid loop can include a cold working fluid line leading into the primary borehole and a hot working fluid line coming out of the primary borehole. A secondary fluid loop can be located down the primary borehole, where the secondary fluid loop is in thermal contact with the geothermal reservoir. A downhole heat mining device can control a rate of heat transfer from the secondary fluid loop to the primary fluid loop by selectively controlling fluid flow through the primary fluid loop, the secondary fluid loop, or both.

A geothermal heat mining system can operate within a single primary borehole in a geothermal reservoir. A primary fluid loop can include a cold working fluid line leading into the primary borehole and a hot working fluid line coming out of the primary borehole. A secondary fluid loop can be located down the primary borehole, where the secondary fluid loop is in thermal contact with the geothermal reservoir. A downhole heat mining device can control a rate of heat transfer from the secondary fluid loop to the primary fluid loop by selectively controlling fluid flow through the primary fluid loop, the secondary fluid loop, or both.

A geothermal development system includes a ground lifting system, a large-diameter shaft, an underground high temperature and high pressure heat transfer pool, a heat transfer diversion channel, a hot mine blasting fracture reservoir formed by an inlet blasting tunnel and a main tunnel, and a removable sealing device. The injection pipe and the collection pipe are set along the large diameter silo wall in the geothermal development system. The injection pipe is connected to the collection pipe through the heat transfer diversion channel in the dry hot rock. The circulation main roadway is arranged around the underground high temperature and high pressure heat transfer pool. Multiple blasting roadways are set along the main roadway level to form hot mine blasting fracture reservoir with loose blasting by caving method. A movable sealing device is arranged above the blasting layer of the large-diameter shaft.

A geothermal development system includes a ground lifting system, a large-diameter shaft, an underground high temperature and high pressure heat transfer pool, a heat transfer diversion channel, a hot mine blasting fracture reservoir formed by an inlet blasting tunnel and a main tunnel, and a removable sealing device. The injection pipe and the collection pipe are set along the large diameter silo wall in the geothermal development system. The injection pipe is connected to the collection pipe through the heat transfer diversion channel in the dry hot rock. The circulation main roadway is arranged around the underground high temperature and high pressure heat transfer pool. Multiple blasting roadways are set along the main roadway level to form hot mine blasting fracture reservoir with loose blasting by caving method. A movable sealing device is arranged above the blasting layer of the large-diameter shaft.

An underground heat exchanger has a bottomed tubular flexible bag body accommodated in an accommodation hole portion in the ground, and an outer tube accommodated in the accommodation hole portion, vertically extending along an outer surface portion of the bag body and communicating in its lower end with a lower end of the bag body. The outer surface portion of the hardening resin bag body can cover an inner wall portion of the accommodation hole portion in a closely contact state with the bag body being inflated. The bag body is hardened in the covering state, a lining tubular body formed by the hardening can form a liquid storage tank for storing a heat medium liquid in its internal space, and the outer tube is pinched between the outer surface portion of the bag body and the inner wall portion.

A geothermal heat utilization system includes a first well having a first upper opening and a first lower opening, and a second well having a second upper opening and a second lower opening. The geothermal heat utilization system further includes a first pipe, a second pipe, a first heat exchanger, and a second heat exchanger. The geothermal heat utilization system is capable of supplying underground water of an upper aquifer from the first upper opening to the second upper opening via the first pipe, and the geothermal heat utilization system is capable of supplying underground water of a lower aquifer from the second lower opening to the first lower opening via the second pipe.

A geothermal heat utilization system includes a first well having a first upper opening and a first lower opening, and a second well having a second upper opening and a second lower opening. The geothermal heat utilization system further includes a first pipe, a second pipe, a first heat exchanger, and a second heat exchanger. The geothermal heat utilization system is capable of supplying underground water of an upper aquifer from the first upper opening to the second upper opening via the first pipe, and the geothermal heat utilization system is capable of supplying underground water of a lower aquifer from the second lower opening to the first lower opening via the second pipe.