1. A cold water anti-freeze mix is pumped around energy absorbing pipes in the ground and it increases in temperature.
2. The water then passes into one side of an evaporator heat exchanger. On the other side is a cold, low pressure refrigerant liquid.
3. As the refrigerant and water both pass through the evaporator’s coils remaining separate), heat energy from the water passes to the refrigerant. This causes the refrigerant to increase in temperature, and, due to its low boiling temperature, change to a gas.
4. The refrigerant gas then enters the compressor, where its temperature increases as a result of the compression process (much like a bicycle pump heats up during its use).