North Devon Homes, Rock Park

Ground source Review North Devon Homes, Rock Park ǀ Exterior of Bungalow

Ground source Review: North Devon Homes, Rock Park.

Kensa Contracting delivered a retrofit scheme replacing a central plant oil boiler system with a shared ground loop array ground source heat pump system to provide heating and hot water to eight terraced bungalows in Devon.

  • Winner: Sustainable Project of the Year (HVR Awards 2016)
  • Winner: Large Scale Project SW Region (Energy Efficiency & Retrofit Awards 2016)
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Ground source Review: North Devon Homes, Rock Park

Rock Park in Devon is an interesting site: featuring eight bungalows owned by North Devon Homes and an old care home owned by North Devon District Council, all nine properties were previously provided with heating and hot water by an inefficient communal oil boiler housed in a central plant room within the care home.

The old boiler was coming to the end of its life and there was uncertainty about the future of the council-run care home, (which has since been shut down), meaning that North Devon Homes would soon lose access to the boiler system. Also, the tenants had very limited control over their existing heating system; being unable to ever switch off the bathroom radiator which reached such high temperatures that they often had to open windows even in the winter, wasting energy and money.

North Devon Homes was therefore looking for a more reliable and efficient source of heating and hot water for its vulnerable and elderly tenants at Rock Park. Ben Ashfold, General Practice Surveyor at North Devon Homes, had worked with Kensa on a ground source heat pump project in a former role at Westward Housing and had seen first-hand how the technology helped to lower fuel bills and provide a sustainable and reliable source of heating and hot water for tenants. He approached Kensa Heat Pumps to talk about whether ground source could help the tenants of Rock Park.

Kensa specified a shared ground loop array ground source heat pump system as the solution. This involved drilling a network of seven communal boreholes to harness heat energy from the ground. An individual Kensa 6kW Shoebox Twin ground source heat pump was installed in each bungalow meaning that no central plantroom was needed and each household receives its own bill direct from an energy provider. The communal borehole array reduced both costs and timescales as the drillers could deliver a smaller number of deeper holes.

The small and compact Kensa Shoebox Heat Pumps along with new hot water cylinders were housed in the tenant’s airing cupboards with the pipework running through the loft.  In order to ensure that the ground source heat pump system would work efficiently, North Devon Homes replaced the old radiators in the bungalows, ensuring that they were correctly sized to increase the heat pump’s performance. Dynamic heating controls were also installed in the form of a twin channel timer from Honeywell and thermostatic radiator valves, allowing tenants to control the heating and hot water separately.

Drilling was undertaken by specialist company GeoDrill, who adapted their machinery to operate effectively in the challenging slate geology in the area. The internal installation was undertaken by Kensa Installer Partner, RES Devon, who accommodated extra requests from North Devon Homes, including painting any pipework that was on show, as well as carefully sanding and filling any holes.

The project is eligible for the Non Domestic Renewable Heat Incentive (RHI – this scheme has closed) due to the micro-district heating system, which has been pioneered by Kensa to enable social housing providers to access this attractive strand of the Renewable Heat Incentive.

Feedback about the system has been positive with tenants reporting that they are happy with the level of heat, and very pleased with the controls especially as they allow them greater flexibility over their own heating.

Ben Ashfold, General Practice Surveyor at North Devon Homes, said:

This has been a really exciting project for us at NDH which supports us in our aims to improve our customer’s homes and make them more affordable and comfortable to live in. The new heating systems will provide a sustainable source of heating that will benefit our customers for years to come. The innovative borehole array has helped access funding and ultimately made this project a possibility.”

The scheme was completed in July 2015 and is expected to save residents £110 – £130 a year on their energy bills. In addition to fuel cost savings, the ground source heat pump system will also help North Devon Homes lower its housing stock’s carbon dioxide emissions.

David Broom, Commercial Director of Kensa Contracting, said:

This scheme is a great example of how a ground source heat pump installation can be used in social housing applications to reduce tenant fuel bills and housing stock carbon emissions, but to also improve the comfort of the properties. Kensa’s unique micro district system architecture also allows each resident to pay their own fuel bill rather than pay an equal share of a communal bill, so they have much greater control over their energy costs.

He continues:

North Devon Homes has invested in an infrastructure that will provide three quarters of the heat required for these building, for free, for the next 100 years, providing long term security of low running cost for the residents of the scheme.

In 2020 from selecting 3 random properties out of the total 8 it shows that in the 5 years since the installation the properties have consumed 965 kWh (lowest) to 2,393 kWh (highest) of electricity per year giving energy bills of £154 – £383 per year. Heat loss calculations predicted 2,800 – 3,000 kWh per year heat pump consumption therefore showing the residents are clearly controlling their systems well.

Key Facts

  • 8 bungalows, 7 boreholes
  • Micro District heating system
  • Kensa 6kW Shoebox Twin
  • Replacing communal oil boiler
  • New wet radiator system
  • Eligible for the Non Domestic RHI (this scheme has closed)

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