GSHP Case Studies
GSHP Association members have provided a number of notable ground source installations. A number of interesting case studies are highlighted below. They show that ground source heat pumps can provide the best heating solution for buildings from small one bedroom bungalows to Regency mansions.
A GSHP can provide heating successfully to old buildings as well as new, to buildings in towns as well as buildings in the country, and to factories, hospitals and schools as well as to homes.
Robinson College, Cambridge
St Cuthman's Retreat, Sussex
A retrofit water source heat pump installation uses high temperature heat pumps at St Cuthman's Retreat to service existing radiators and employs a control system to give priority to the water source heat pumps over the existing oil fired boilers.
The heat pumps retieve heat from closed loop coils in the adjacent lake, as St Cuthman's retieves Renewable Heat Incentives from Ofgem.
Cambridge Terrace, Regent's Park
Half of Cambridge Terrace is being refurbished as a single dwelling – the largest residence in London after Buckingham Palace.
A ground source energy system has been chosen for this Grade 1 listed Nash terrace to provide renewable heating and renewable cooling. The terrace will be cooled in summer by transferring heat down to a thermalbank in the ground. When heating is required in winter, heat will be recycled back to the building from the thermalbank to maintain a comfortable temperature in the building all year round.
Tattleton Estate, West Sussex
Five buildings on the Tattleton Estate are linked with 1,000 metres of underground pipe to a closed loop system circulating water from the lake on the equestrian estate. Each building now uses its own heat pump to provide heating and hot water from the central source side ground array instead of relying on oil fired boilers and LPG.
Ambitious GSHP retrofit in social housing
A retrofit upgrade programme featuring ground source heat pumps in social housing is set to halve the energy bills of over 130 residents following a landmark scheme for Trent & Dove Housing.
The innovative design sees a small ground source heat pump installed in each property to meet all its heating and domestic hot water needs. The pumps, which are served by a communal ground array, are expected to halve the tenants' heating costs compared with the electric night storage heaters being replaced.
GSHP retrofit replaces oil heating
The owners of an old property near Corwen in Denbighshire recently opted for ground source heating to help curb their energy bills.
Dragon Drilling (Water & Energy) Ltd installed a ground source heat pump system to replace the old oil fired boiler which had been supplemented by burning coal and wood to curb the annual bills of over £3,000. The old system had provided part time heating - but even then had struggled to keep the building up to temperature.
The owners had reported that with the old system, "We never felt truly warm".
Precision Engineering Factory, Hampshire
Ground source energy has been chosen for a new precision engineering factory in order to provide renewable heating and renewable cooling. Machining of components in exotic metals requires air temperatures to be controlled very precisely in order to meet the exacting tolerances required by aerospace clients. The new factory is cooled in summer by transferring surplus heat down to a borehole field in the ground. When heat is required in winter, heat is recycled back to the building from the borehole field to maintain a comfortable temperature in the building all year round. This is achieved by an automated system that balances the temperature in the building with the stable temperature natural to the ground by transferring heat from the ground in winter and storing surplus heat in the ground in summer: this achieves recycling of heat using precision engineering.
Water and heat from a single borehole
During the renovation of this listed farmhouse, it was decided to replace the spring fed water supply with a water well. Earthtest Energy suggested that the same borehole could provide space heating and domestic hot water using a Soleco open loop heatpump. The underfloor heating fitted throughout the property uses water at up to 45°C, whilst domestic hot water is heated to 60°C. The installed system generates Renewable Heat Incentive payments of £43,841 plus inflation over seven years, which significantly exceeded the cost of the total installation. Annual savings of £1,800 against biomass pellets, make this cost efficient solution, which also minimises carbon dioxide emissions.
Balanced Energy Networks, London
Innovate UK has awarded £2.9m towards the £4m BEN Consortium which is building a Balanced Energy Network at London South Bank University to demonstrate innovations in integrated energy supply chains.
The Balanced Energy Network incorporates a heat sharing network which is designed to provide a more cost effective, flexible, and scalable alternative to conventional district heating network technology. Heat sharing networks transfer warmth via underground piping circuits between buildings at near ground temperature and extract it via heat pumps in each building.
Buildings which need cooling use heat pumps to reject heat to the ground circuit – to the benefit of those that need heating.
The buildings in the network contribute to load balancing of the Grid, and earn revenue, by using Demand Side Response across the Internet of Things.
Heat Pump Efficiencies
The first ever Renewable Heat Incentive accredited system was a 26kw water source heat pump which heats a 750m² office development in Yorkshire. A report published by the Department of Energy and Climate Change on 11 February 2016 showed that it was also the most efficient of those monitored by an independent consultant. The one year study, which looked at both the efficiency of the heat pump and the efficiency of the whole heating system, revealed that the system installed by Earthtest Energy for Booth Brothers (Printers) Ltd was a huge 70% more efficient than the mean performance of the other systems monitored, and beat its nearest rival by 20%.
The report concluded "that it is possible to design, install and operate heat pump systems that provide a high seasonal performance factor, but that this high level of performance is not being realised on some installations".
See the full report on Heat Pump Monitoring.
Merton Community Centre
The architects for the Merton Community Centre decided to go for the "elegant" solution in which one integrated system could provide both heating in summer and cooling in winter (as well as hot water all year round and the freedom not to have to organise, feed and manage a biomass boiler).
Old Oak Common Crossrail Depot
Bombardier's new depot for its Crossrail fleet will have 33% of its energy demand met by renewable energy when it opens in 2018. It will benefit from ground source heating and cooling, photovoltaics and solar thermal and generate annual savings of £100,000. The installation by GI Energy for Taylor Woodrow is expected to achieve a ten year payback, as well as saving 530 tonnes of CO2 a year.
Solar Powered District Heating, Bristol
A Solar Powered District Heating Project in Bristol uses PV powered heat pumps to charge the ground with summer heat for easier extraction of heat in winter: Solar Powered District Heating .
The CHOICES consortium behind the project decarbonises heating by using green electricity in summer to charge an interseasonal heat store. Ground source heat pumps are used in winter to transfer heat into community buildings without burning fossil fuels. Grid balancing systems are employed to ensure that electricity is not demanded from the grid at times of peak use.
The consortium has created a district heating system based on solar energy and seasonal thermal energy storage which can be scaled up to serve additional buildings and be readily employed in other locations.
DECC has published case studies on GSHP installations
DECC has also published a number of case studies of succesful GSHP installations across the country:
Shepway Court residents enjoy greater warmth and lower bills
GSHPs keep Shepway Court sheltered housing residents comfortable at a price they can afford.
Ground Heat drilled 12 boreholes 150 metres deep to draw heat from the ground and provide heating and hot water to 40 units in Salford, Greater Manchester via two 46kW GSHPs.
Individual thermostats allow each tenant to control their own room temperature and they will now each spend around £260 a year for their heating and hot water – £85 a year less than they were paying with the previous gas boiler fired system.
The installation was completed by Ground Heat Installations Ltd in two months.
Large new home off the gas grid enjoys low running cost from automated GSHP system
GSHP heats a large new home off the gas grid in North Yorkshire. The system draws heat from 2 boreholes 150 metres deep and the ground source heat pump distributes the heat through underfloor heating pipes and heated towel rails as well as providing all the domestic hot water. The system was designed and installed by isoenergy Ltd.
"We are thrilled with the new system", says the owner. "We don't have to think about it at all. It's always on in both the summer and winter, but the system self-adjusts the temperature so we always feel comfortable. It's so unlike the other heating systems that we have used. We got used to it very quickly and can't believe how simple it is to use".