Kensa Heat Pumps is supplying Shoebox heat pumps to a new landmark luxury housing development comprising forty apartments and houses currently under construction amongst the famous dunes of Perranporth beach in Cornwall.
“The Dunes”, set for completion in June 2018 by developers Acorn Blue, has completed the groundworks stage for the ground source heat pumps, which will be sited inside each of the dwellings, providing 100% of the two apartment blocks, five coach houses and four beach houses’ heating and hot water requirements.
Spring 2017 Status: Groundworks Complete
The micro-ground source heat network approach qualifies ‘The Dunes’ project for 20 years of income via the Government’s Non-Domestic Renewable Heat Incentive (RHI). It is expected that the RHI income for The Dunes will more than offset the cost of the system.
All the properties will have either a 6kW or 3kW Shoebox heat pump within their own property to supply 100% of heating and hot water demand. These heat pumps will be supplied by 19 boreholes connected together into five distinct ground arrays. On one array 17 individual apartments will be provided heat to their own individual Kensa Shoebox heat pump from one double-probe borehole. In total 3km of borehole pipework has been installed.
Take a 360° tour of The Dunes site during the groundworks stage:
As with all our projects borehole design is crucial to heat pump performance and long term customer satisfaction, although the tight space restraints at The Dunes further impacted our design requirements. It was felt that it would be prudent to keep all the drilling activities away from the other facilities that will be brought onto the site including drainage, sewerage and utilities. The boreholes are arranged at the seaward peripheral of the site. A 6 metre exclusion zone was put in place where possible to prevent drilling activities impacting both the environment and health and safety on the site. This left little room for the boreholes to be positioned, the design was changed to reflect this lack of space.
The communal arrays are made up of either single or double 40mm borehole probes with borehole centres ranging from 6 to 8m. The smaller centres between boreholes called for deeper boreholes and on the largest array consisting of 17 properties double probes have been installed to ensure the correct flow rates are achieved on all the heat pumps in a worst case scenario. These design elements coupled with standard design practice at Kensa mean that we can offer a 20 year design guarantee and can satisfy both ourselves and Acorn Blue that the systems will perform as expected.
Drilling on site wasn’t without its challenges; geology at site was found to be sand for the first 6-10m at which point the drill rig encountered metamorphosed mudstone in the form of slate to depth of 130m. The slate has bands of quartz within it which slowed drilling considerably. That being said all 19 boreholes were drilled and installed to a high standard on time by operatives of Geo Drill, our drilling contractor on this project.