Case Study

Retrofit GSHP installation, with boreholes, Norfolk

Mr R lives in a large, detached house in the city suburbs of Norwich, he was looking to replace his existing heating system of a gas boiler and radiator. His main objectivesNACHP Winner and Highly Commended 2022 for changing his heating system were to have a future proofed renewable heating system for his home with the highest level of energy efficiency as possible.

Mr R had done extensive research on air and ground source heat pumps and whilst an air source heat pump would have been a cheaper solution and was considered, his priority was to maximise efficiency with a ground source heat pump. Whilst he had a large garden, he did not have enough suitable area for the ground collector and therefore boreholes were the only option open to him.

The old utility room was used as the plant room as the this the only available space to used.

When the solution was specified, the total heat requirement meant that we were looking at recommending a 16kW NIBE GSHP. A 16kw heat pump requirement meant that the client required 3 phase electricity, this was pushing the project costs beyond budget.

Highly Commended Solution

Therefore, we looked at how we could provide an alternative solution whilst also working to the customers main objective. A recommendation was made to add heat insulation to a small section of the outside walls, this reduced the heat requirement for heating and hot water to 44038 kWh/yr. Taking this into account it then meant that we were able to recommend a 15kW Steibel GSHP. A 15kW Steibel GSHP is able to run on single phase electricity, therefore removing the prohibitive cost of 3 phase electricity.

Steibel Eltron GSHP

3 x 150 metre boreholes where calculated to be needed for the ground source heat pump.

14 radiators were upgraded along with the pipe work to the property as the current pipework was undersized and therefore the new pipework allowed the correct flow rates.

CO2 Savings with this GSHP installation

The customers main objective was to reduce carbon output from his home. A ground source heat pump was the solution which produced the least amount of carbon
The estimated annual CO2 emissions for his existing gas boiler system was 9247.98 kg CO2/kWh per year.

The estimated annual CO2 emissions for the newly installed GSHP is 1338.37 kg CO2/kWh per year.

Therefore by installing the GSHP system there is a saving of 7582.16 kg CO2/kWh per year.

Mr R “I looked for members of the Ground Source Heat Pump Association, with offices in Norfolk, and I found three companies to choose from. I then looked at each company’s website, and R A Brown’s site was the most informative. Questions like “How much will it cost?”, or “How long will it take?” are difficult to answer – it depends on the size of the house and many other factors. Nevertheless, R A Brown’s website gave examples that were helpful and informative.”

“I asked R A Brown for quotes for both Air Source and Ground Source systems, and they quoted for both. I went with the Ground Source option for several reasons:

Trenching work

i)  Quieter, i.e. no noisy air source fan just outside the window.
ii) Ground source has a lower electricity demand in the depths of winter when you most need the heating.
iii) Overall, the ground source option was more economically attractive than air source.”

Mr R said “ The result is that our gas boiler has gone, which is great. Our kitchen was already fully electric, so now we don’t burn any gas at all, and that is a significant step towards reducing our CO2 emissions. I am very satisfied with the installation, which was carried out with skill and care by R A Brown and the results of the heating system have matched my expectations.”

Mr R concluded “In the course of the project I spoke with half a dozen different members of R A Brown’s staff, and they were all helpful and reliable.

Probably the biggest challenge was delays in the supply chain, leading to installation delays. Good communication and flexibility from all parties were the key to handling the delays.”

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