Green Gables, Somerset

Ground source review: Green Gables family home

Fulfilling green & money-saving motivations

Green Gables is a family home in Somerset, consisting of two attached buildings. Looking to save money on heating bills and reduce their carbon footprint, the homeowner wanted to rule out their reliance on oil heating.

After enlisting renewables installer, Evergreen, to assess the property and discuss options, they both decided that ground source heat pump technology was the most efficient choice with the lowest running costs. With the help of Kensa, Evergreen – who have worked as accredited installers for Kensa since 2015 – came up with a system design fit for the family home.

The installation & electricity supply upgrade

As there were two buildings on the site, two 15kW Kensa Evo ground source heat pumps were supplied – one to each dwelling – to provide all heating and hot water demands.

The two heat pumps were the perfect match for a Shared Ground Loop Array – Kensa’s pioneered system, which transfers ambient-temperature heat energy from the ground to each individual Evo ground source heat pump located inside each of the dwellings. The Evo then upgrades the heat energy to provide heating and hot water on demand. Using this system meant that the owner was eligible for the Non-Domestic Renewable Heat Incentive (RHI: this scheme has now closed – please visit this page to explore other funding).

The incoming electricity supply was upgraded by Western Power from a single-phase to a three-phase connection to accommodate the higher output and the two electricity meters required.

Evo heat pumps installed in plant room

Ground array process

As the property had plenty of land, slinky pipes were the ideal ground array to extract the heat. The slinkies and header pipework were installed in trenches, and sand was used to protect the pipework and ensure the best possible heat extraction.

Evergreen also carried out the necessary alterations and additions to the existing space heating systems, and the upgrade of the electrical system.

Slinky pipes installed in trenches

Solar PV for self-sufficient energy

The ground source heat pump system was also coupled with a ground-mounted Solar PV system, which further improves the property’s sustainability by utilising solar energy and converting it into electricity. As this system is connected to the grid, it can export electricity that isn’t used and import it when there is not enough sunlight. Evergreen installed two SolarEdge immersion controllers, which send spare generated power from the solar PV system to the immersions heaters – making the most of self-generating power and losing less to the grid.

The owner of Green Gables is able to monitor how much power is being generated by the Solar PV system, so he can adapt the settings to utilise as much of the free self-generated power as possible.

Ground-level solar PV system