We were contacted by our client to give a price for some GSHP boreholes for a system they were having installed by a local heat pump company. As is the case with most GSHP companies they do not do their own drilling. We had worked with the heat pump company on many projects over the last 5 years.
Although there was enough room for horizontal collectors at the site, the ground conditions (chalk with flint and very little top soil well above the rest water level) meant that boreholes for GHSP would be the best option.
One of the points discussed was for the client to have an open loop heat pump system which would enable them to draw water from a water borehole, run it through a heat pump and return the water into a recharge borehole. We offered caution to this idea as guaranteeing the 60 litres per minute flowrate from the borehole would have been optimistic.
We installed 6 no. GSHP boreholes to a depth of approximately 125 m. The main contractor dug the return pipe trenches that blinded them with sand and we fusion welded the return pipes from the boreholes to the external manifold and back into the plant room.
The system was then left tested, certificated and filled with an anti-bacterial biocide for the heat pump installer to connect to.
Whilst drilling on site our client asked whether a water borehole would be feasible to supply them with drinking water and irrigation. Using the information gained from the GSHP boreholes we were able to suggest a 98m water borehole. We installed the waterwell and the pumping equipment for their supply. We did flow rate testing and analysed the water quality which runs through a sediment and UV filter as a precaution.
Although the water borehole was very successful, our initial thoughts regarding flow rate were realised and a continuous flow of 24 litres per minute is achievable which would not have been high enough to support an open loop ground source system.
“Where I thought Nicholls were outstanding was their ability to make complicated information easily digestible. Unlike others, Nicholls also seemed to try to help us to understand the options rather than push one particular option. Ben and Ed’s knowledge was matched only by their enthusiasm and patience.”
Mrs Al Portman, January 2015