Abstract: A liquid-heating system has a solar energy collector exposed to solar radiation, a geothermal heat exchanger buried in the ground at a depth between 0.5 m and 5 m, a heater through which a liquid to be heated passes, and a heat pump having a sink side connected to the heater and a source side connected to the geothermal heat exchanger or to the solar energy collector. A first controller or valve setup connected to the heat collector can in one position connect the solar energy collector to the water heater such that heat collected by the solar energy collector is applied to the water heater. In another position it can connect the solar energy collector to the geothermal heat exchanger such that heat collected by the solar energy collector is applied to the ground surrounding the geothermal heat exchanger.

Abstract: A liquid-heating system has a solar energy collector exposed to solar radiation, a geothermal heat exchanger buried in the ground at a depth between 0.5 m and 5 m, a heater through which a liquid to be heated passes, and a heat pump having a sink side connected to the heater and a source side connected to the geothermal heat exchanger or to the solar energy collector. A first controller or valve setup connected to the heat collector can in one position connect the solar energy collector to the water heater such that heat collected by the solar energy collector is applied to the water heater. In another position it can connect the solar energy collector to the geothermal heat exchanger such that heat collected by the solar energy collector is applied to the ground surrounding the geothermal heat exchanger.

Abstract: A building having a plurality of rooms in at least one zone is heated or cooled by heating or cooling a heat-transfer, medium outside the rooms, conducting the heated or cooled medium through conduits to the rooms, and providing a respective controller for each zone. Respective heating/cooling parameters are established for each zone by predetermination or measurement, and the heating or cooling of each zone with the heat-transfer medium is controlled by means of the controllers in accordance with the respective parameters by regulating the amount of the medium conducted to the zone or a temperature of the medium conducted to the zone.