The Geothermal (low enthalpy) Energy Unit, "EG5B", designed by EDIBON, consists of a cooling circuit, a small tank with pipes covered with water (bath) and a chilling unit (heat pump). The inside of the earth is simulated with them. There is another tank where the sanitary hot water heated by the unit is stored.
The cooling circuit consists of a compressor, an air condenser/evaporator, and two water condensers/evaporators. The reason is that the unit has a 4 ways valve that can detect if it is summer or winter by the environmental conditions. According to this, it sends the refrigerant gas to one or another exchanger. So they are able to work as evaporators or condensers of the refrigerant liquid.
The ground is simulated by means of a small tank that covers some pipes and a heat pump. The water of the tank is at a constant temperature, the same temperature that the earth has at 20 m of depth (15ºC [59ºF] approximately). This water goes to a bath, heating or cooling the water that flows through the pipes immersed in the bath.
Finally, there is a tank to store the water heated by the unit. It simulates the sanitary hot water of a house.
The unit has a cycle inversion valve, which is able to simulate winter and summer conditions, as it was mentioned before. Since the temperature of the earth at 20 m of depth is always 15ºC, this temperature will be higher than the environmental temperature in winter, therefore, the ground is used to heat (heating mode use). However, the environmental temperature in summer will be higher than 15ºC, so the ground’s water will be used to cool (refrigerating mode).