An Open-loop ground source heat pump installation could:

Meet all your heating needs

Meet all your water needs (subject to analysis and suitable filtration)

Provide an additional grey water supply

and all at a fraction of the running cost of a conventional gas boiler.

How do they do that?

The Earth continually absorbs heat from the sun and stores it in the ground, below the Earths surface.  At depths below 1 metre, the ground temperature is consistently between 8°C and 14°C.  A ground source heat pump is designed to use this constantly renewed energy to supply domestic heating and hot water.

With an Open-Loop installation, a water supply borehole would be drilled and water at a temperature of around 11°C pumped into the building, where flow could be diverted to feed both a potable (drinkable) water supply and an open-loop heat pump.  The heat pump extracts heat from the water and uses it to raise the temperature of water being circulated throughout the house.  There are usually two separate water circuits, one for space heating up to 55 °C and another for domestic hot water up to 65°C.

System Diagram2

Cooled water at around 6°C is directed from the heat pump back into the ground, where the ground temperature warms the water back up.  A harvesting tank can be installed to store the discharge from the heat pump, thereby providing a water supply for garden irrigation or other ‘grey-water’ use.  Unlike rain water harvesting tanks that are only replenished when it rains, a heat pump harvesting tank is replenished whenever the heat pump is in operation.  If the harvesting tank is buried in the ground, the water starts to reclaim heat immediately.