A ground-coupled heat exchanger is an underground heat exchanger loop that can capture or dissipate heat to or from the ground. They use the Earth's near constant subterranean temperature to warm or cool air or other fluids for residential, agricultural or industrial uses. If building air is blown through the heat exchanger for heat recovery ventilation

Heat recovery ventilation

Heat recovery ventilation, also known as HRV, mechanical ventilation heat recovery, or MVHR, is an energy recovery ventilation system using equipment known as a heat recovery ventilator, heat exchanger, air exchanger, or air-to-air heat exchanger which employs a counter-flow heat exchanger between...

, they are called earth tubes (also known as earth cooling tubes or earth warming tubes) in Europe or earth-air heat exchangers (EAHE or EAHX) in North America.