Applications for Heat Exchangers Geothermal heat pumps: geothermal hot water heats binary fluid for space heating or domestic hot water. The heat can be from geothermal hot springs, or simply coils of pipe laid in the ground. If the ground temp is even just ten or twenty degrees warmer than the cold water source, the geothermal heat offsets that much energy that a water heater has to put in to heat the water for domestic purposes. Car radiators: Airflow across radiator tubes extracts heat from the coolant or water that heats up in the car engine. Air-source heat pumps: Similar to a ground-source heat pump, but the temperature difference is derived from the ambient air temperature rather than the soil. District heating: Multiple buildings can be connected to a single heat source, such as a geothermal well. Each structure or process connected to the geothermal water requires its own heat exchanger to isolate the operating fluid from the geothermal fluid. Most of Iceland's residences are heated by the country's abundant geothermal resources, and Chena Hot Springs heats the entire resort with the geothermal water. Downtown Fairbanks and the UAF campus are also examples of district heating employing heat exchangers on every building; however, the heat source is coal rather than geothermal. Condensors and evaporators: Transfer heat extracted from refrigerators or air conditioners to Organic Rankine Cycle power generation: As demonstrated at Chena Hot Springs, low-temperature power generation is possible. The geothermal water transfers heat to a refrigerant with a low boiling point through a shell-and-tube heat exchanger. The boiling refrigerant produces steam, which in turn drives a turbine.