Ground source heat pumps provide cost effective heating in off gas grid social housing

A development of 12 affordable homes in a quiet Somerset village has achieved South Western Housing Society’s ambition to help families stay connected to their local area, quite literally.
The mixed development of 1-bedroom flats and 3 and 2-bedroom semi-detached houses and bungalows, features individual Shoebox ground 

source heat pumps inside each home, connected by a Shared Ground Loop Array (SGLA) featuring boreholes drilled to a depth of up to 138m. The Shared Ground Loop Array delivers ambient temperature heat energy to each home, with the Shoebox heat pump then upgrading this to a higher temperature to provide the homeowner with low-cost, zero emission energy, and complete heating independence.
The SGLA configuration allows South Western Housing Society to offset the ground source heat pump costs via income through the Non Domestic Renewable Heat Incentive.
The houses on the development in Mark are clustered into groups of two, connected by one borehole. The four flats are connected to one borehole, also, equating to five Shared Ground Loop Arrays on the site in total.
The Shared Ground Loop Array offers further advantage in the flats, where due to the ambient temperature (-5°C to 20°C) circulating the flats risers and corridors, there is no contribution to potential overheating; a common issue with traditional heat networks which circulate heat at temperatures of 65°C to 85°C
With a ground source heat pump installed inside each property, this provides the local homeowners complete control over their own energy use, and their own electricity bill; running costs savings of 48.4% are expected compared to the alternative of LPG in the off-gas grid area.
By choosing to install a non-combustion heat source in the form of ground source heat pumps, as opposed to LPG or gas, over the system’s 40 year lifetime the development in Mark is expected to have prevented the equivalent of over 132kg of harmful local NOx emissions, and 539 tonnes of CO2.
Each property’s heating system features radiators with a programmer, thermostat and TRVs and 150L water cylinders, and heating controls.
The new homes are excellent examples of good design and the embodiment of modern technology to ensure they sit well with the local character and tradition. The properties include ground source heat pumps, that will provide both heating and hot water from a sustainable source, which the occupier and the society will benefit from long term with reduced energy bills and happy tenants.
At an early stage, initial feasibility, viability, technical matters and costings as well as the vital Non Domestic Renewable Heat Incentive were examined.
Tuckers Close provides a good example of how GSHP’s can be used in new build development to provide the best possible outcome for all stakeholders. The tenants receive comfortable, controllable heating at a cost lower than mains gas, despite being in an off gas area. The developer provides a building that, thanks to the efficiency of the heat pump, provides a low carbon solution, which meets the planning sustainability requirement by delivering over 20% on site renewables, and the client has a reliable, low lifetime cost heating solution, which is simple to operate and maintain, as well as a 20 year income stream in the form of the RHI which more than covers the capital cost of the installation.