Open Loop Ground Source Heating & Cooling
Ground Source systems have actually been around in North America, Scandinavia and Mainland Europe for a lot longer than they have in the UK. It’s taken a while for the UK industry to progress but the growth is here now. It needs to be understood however, that coupling a building to the ground to extract or reject energy takes experience and know-how.
On larger schemes, buildings tend to be best served by open loop borehole systems if there is an aquifer beneath the site to exploit.
Open Loop systems see groundwater abstracted at ambient temperature from a water bearing sub-strata known as an aquifer. The groundwater is pumped up from the well or borehole, passed through a plate heat exchanger or heat pump before being re-injected back into the ground usually from the same horizon from which it was originally sourced.
For buildings with heating/cooling demands of perhaps 200 kW or more (e.g. a large office building), open-loop systems can be more economic than closed-loop systems. They can also offer what is known as free-cooling where the naturally low temperature of the groundwater ( 10-14°C )
In order to consider an open loop borehole scheme, the presence of an aquifer of sufficient productivity and water quality must be beneath the target site. If the chosen site is close or adjacent to a river or lake then there is the potential to use this as the energy source or sink but surface water systems have annual temperature profiles that closely follow the air temperature so drawing water from it during a cold winter snap can have undesirable consequences and this needs to be considered in the UK.
Contact us to learn more about open loop borehole systems and how we can help you with your project.