|Cartoon illustrating the concept of using shallow urban aquifers and |
heat pumps in district heat networks.
Credits: City of Cardiff Council/BGS/WDS Green Energy Ltd
The heat pump system works by passing groundwater through a heat exchanger where 2 Kelvin degrees of its thermal energy is transferred to a heat pump which uses a gas phase-change to raise the water temperature to a useable 46oC. The heat pump keeps the inside of the school at a comfortable 22oC using a renewable energy resource that has low carbon emissions and is cheaper to run than the old gas boilers.
|The GSHP pilot plant room and associated monitoring and data telemetry. (Credit: BGS-UKRI)|
Although open-loop ground source heat exchangers are not suitable in all geological environments, we have been working to understand the wider 3D geological and hydrogeological settings at a city-scale, with the release of a 3D superficial geology model of Cardiff. This evidence will allow better ‘above’ and ‘below-ground’ planning and regulation, and will (we hope) stimulate market growth in renewable energy systems and supply chains. More demonstration projects like this are needed to improve the image and public perception of renewables. Local authorities can invest in renewable energy such as heat pumps using interest-free Government-backed finance schemes like the SALIX finance and the Renewable Heat Incentive (RHI) scheme. Case studies such as ours can give society and business the confidence to invest in shallow geothermal technologies to accelerate the energy transition.
David Boon and Gareth Farr have jointly managed and overseen the creation of the Cardiff Urban Geo Observatory (2014 – 2018). The project has evolved naturally out of City Region Geoscience project (under former Chief Geologist Wales, Dave Schofield), the 2015 InnovateUK feasibility project (led by David Boon), and by listening to local stakeholders in Wales. Massive thanks go out to the project team: Ashley Patton, David Schofield, Alan Holden, Rhian Kendall, Laura James, Steve Thorpe, Corinna Abesser, Johanna Scheidegger, Jon Busby, Susanne Self, BGS Dando Drilling Facility, and others. Key partners are Cardiff Harbour Authority, City of Cardiff Council, WDS Green Energy, David Tucker (Nu Vision Energy (Wales)), and Innovate UK/ BEIS. @BGSWales