As previously reported by Transition Bath under Bath Abbey’s £19million Footprint project the Abbey will become more sustainable by using hot water from the Roman Springs to heat the Abbey. On Monday 21st November Charles Curnock presented an update on the project.
The mains points of interest from a sustainability perspective from his presentation were:
- The designs for extracting heat from the thermal spring water are almost finalised
- LED lighting will be installed throughout
- They are still interested on installing solar PV panels but no decision has been made yet
Thermal Spring Heating System
The plan is to extract heat from the outflow of the Roman Bath’s from the Great Drain as it passes to the south of the Abbey:
Energy Blades rather than heat exchangers will be used to extract the 45C heat. This will be the first-time Energy Blades have been used in the UK, although they have been used in similar projects in Europe. They should will require less maintenance than heat exchangers which are likely to clog up with material from the outflow of the Roman Baths:
A 250kW to 350kW heat pump will ne used to raise the temperature of the extracted water to about 45C so it is warm enough to heat newly installed underfloor heating under the flagstones of the Abbey’s floor. A gas boiler will be installed as a backup and to support the heat pumps in the very coldest weather. The switch from fossil fuel heating to heat pumps should significantly reduce the Abbey’s carbon footprint, particularly as the electricity grid decarbonises in future.
This arrangement will only be marginally better economically for the Abbey because of the energy required to power the heat pump. However, if they manage to obtain an estimated £30K pa Renewable Heat Incentive subsidy then it will represent a large cost saving for the Abbey.
The underfloor heating should make for a more pleasant environment in the Abbey as it will heat the area just above the floor, as opposed to the current air based heating system where most of the heat rises to the roof. The current air based system will however be retained to reduce sub-floor damp and to counteract the downflow of cold air from the Abbey’s tall windows. It will also help boost the temperature during very cold weather (below -4C).
LED lighting is also being installed, apart from the benefit of energy savings they are significantly more reliable and will reduce the maintenance costs of replacing bulbs in the Abbey’s high chandeliers.
All this work is taking place as part of a much larger program of work over the next 3 years, which will include refurbishing the whole of the Abbey floor, replacing the visitor entrance and extensive works to the south, including using most of the space in existing vaults under the square to the south, to include a new education and interpretation centre.