In this blog, first published on geodrillinginternational.com (June 2019), Dr Matthew Trewhella, Managing Director of Kensa Contracting, shared his views on the potential of using ground source technology for cooling.
On the potential of using ground source technology for cooling
What are the (unknown or lesser known) advantages of using ground source heat pumps for cooling?
The ground will always be more efficient than the air as the source of cooling. However, when you combine heating and cooling options together this advantage increases. For example, if you have a block of flats with a retail (supermarket) on the ground floor then the annual heating load of the flats could be larger than the annual cooling load of the supermarket. In this scenario, the cold stored in the ground (created by extracting heat from the ground to heat the flats) can be enough to provide all (or much of) the cooling demand without the use of a heat pump at all (or at least minimal use). We call this passive cooling and it is many times more efficient than even regular ground source cooling
Is the potential of ground source cooling fully understood and exploited in the UK market?
No, most cooling applications are air source. We have even seen ground source heating and air source cooling in the same building.
When and where (what kind of ground conditions, structures and climates) is it possible and environmentally and financially viable to install and use ground source heat pumps for cooling (heating and cooling)?
Most ground conditions are suitable but the system as a whole works at its most efficient when the cooling load is approximately 50% of the heating load.
In your different markets where do you see the biggest interest in, and utilisation of, ground source heat pumps for cooling?
Flats, commercial space (supermarkets), offices are the mainstream ones but we are also seeing requirements for cooling data centres, electricity sub-stations, underground (tube) stations, and solar PV panels.
Does the requirement for ground source heat pumps to be convertible to cooling require any specific skills from drillers or installers? Are there any other obstacles to exploiting ground source cooling?
The main skill requirement lies with the system designer. It already requires a specialist ground source designer with knowledge of heat pumps and geology to design a ground source heating system. When you add cooling into this, the level of complication increases. It also places a higher level accuracy required from the building designer to correctly model the heating and cooling loads. Once the design is complete, the actual physical installation is straightforward and doesn’t require any skills that aren’t already present in the industry.