Free energy for everyone
Lord Kelvin Scottish physicist who developed the Joule-Kelvin effect which makes systems with refrigerants work
History of heat pumps
Heat pumps are not new technology, as long ago 1843 the first heat pump patent was granted. This was developed using ammonia as the refrigerant gas.
Most people reading this page will in fact have two heat pumps in their home, one in their fridge and another in their freezer, albeit they are used to cool rather than heat, i.e. they operate in reverse to a heating heat pump.
Where does the energy come from?
The sources for both geothermal and air-to water are the sun, for it is that which primarily keeps our atmosphere warm. The ground beneath your feet is in effect a huge heat store for the sun's energy, a heat pump with either a bore-hole or ground loop simply extracts this energy to help heat your water and home. The sun warms the ground in the summer, and it holds it's heat during the winter.
Even in the middle of winter, the ground temperature beneath the surface remains relatively constant, and in most conditions will be between 11° and 13°C at 20 meters deep in the UK.
Heat pumps extract the energy from the ground, and make it available to you in your home. Even air to water can operate successfully when the temperature is as low as minus fifteen degrees centigrade.