Well almost, its a ground sourced heatpump
I've been keeping an eye on exiting developments at both the National Trust and the RNLI, as part of my 'hobby' as a director of Poole Tidal Energy Partnership. Both these venerable institutions are canny with their funds, all raised from volunteers and public subscription. Both are actively looking to reduce their carbon footprint in innovative ways, and are investing in heatpump technology.
http://ntenvironmentalwork.net/ is a great blog. In particular Keith Jones, responsible for the whole of Wales plus Northern Ireland is looking at all forms of renewable power including a seawater powered heatpump for Plas Newydd on the Menai Straits. Keith has enlisted the help of several Welsh Universities (the Seacams project) to help map and plan the development.
And the RNLI, with its headquarters in Poole, has by nature of its work, water always close to their doorstep, and have tested and installed a number of heatpumps - ground and water sourced.
http://rnli.org/aboutus/aboutthernli/Pages/Environment.aspx summarises their approach, but we have been talking to them for a while.
So it was time this weekend to return my son to University in Brighton, and I thought I'd drop by the Shoreham Lifeboat station, which has a ground-sourced heatpump.
The volunteer in the shop initially looked a bit crestfallen when she offered to show us around and I told her my particular interest, but entirely through luck, she said the station manager (another Keith) was on site. We met him on the stairwell, he had just been entertaining crews from other stations. He was happy to show us down to “the cave”, not normally on the tourist trail, where the heatpump sits. The machine is the size of a small washing machine, and they said it heats the station very effectively (the white tank is a temperature stabalising device). We were taken into the crew room, and it felt very warm – he said without needing to use the top-up heating. Indeed (and I had spotted it on approach), although it was a cool January day, they had some of the windows open on the top floor.
This is a groundsource system, with 3 boreholes going straight down 90 metres. Robert from RNLI HQ kindly filled me in on the details, this was the second station that they installed. The basic design of boreholes is based on the idea that roughly 55watts of energy can be extracted per meter of borehole. Therefore 3x 90m boreholes gives 270m of collector which multiplied by 55watts equals 14.8kW. – Allowing for a little safety margin in the design this is the peak power output of the heatpump. Given subsequent experience, they might have taken a different shallower approach, taking benefit from the groundwater adjacent to the eastury.
Really grateful to both Keith at the station, and to Robert at HQ for their hospitality and insight. Tomorrow we're presenting our ideas to councillors, and it is really helpful to know of solid progress from trusted organisations.