Heat Pump Federation

Type

Commercial

Technology

Ground Source Heat Pump

Region

South East

The manor house was a particularly difficult challenge as the property is solid stone, has stained glass windows and has construction elements dating back to the 1400s. It has a total heat loss of approximately 150kW. And in some locations older style radiators had to be retained, precluding the use of low temperature heat pumps. As such, a higher temperature source of heat was required and after discussions with the planners, a bank of 10 x Daikin High Temperature heat pumps was allowed in one location and another five in another location some 100 meters from the building they need to heat. This required the construction of a new small plant room and the installation of a long length of district heating pipe in a trench running through the formal gardens.

Athelhampton House and Gardens is made up of a Grade 1* listed Tudor manor house dating from the 1400s, a reception building with catering and event facilities that also has listed status and a holiday rental cottage. The facilities are open to the public year-round and are a significant local employer.

The site is off the gas grid and has been heated with a mix of LPG and oil, it had a limited electricity supply resulting in frequent power cuts and as a result also had a large diesel generator.

The new owner had a vision to make the property operationally net carbon neutral and bring a historically significant building to a point where it was ready for the next 500 years without adding to global carbon emissions.

The clear objective of the owner was to get rid of all fossil fuel energy sources for all the buildings and operations on site.

The challenges were significant as there was a need for significant generation on-site as well as significant renewable heating and an upgrade to the sites power supplies and connection to the grid.

The entire site however is grade 1* listed. This meant that the normal "fabric first" approach to energy reduction was a challenge as options for retrofit insulation were limited. Insulation was possible in 40% of the flooring using traditional insulation and 60% of the roof space with a mix of mineral wool and hemp insulation. This led to a technology-heavy set of solutions that were designed in detail to work around the sites many challenges.

We face a lot of negativity and incorrect information about renewable heating systems ability to heat anything other than modern, well insulated buildings. This project demonstrates that a building which would "typically" be considered to be impossible to convert to renewable heating is in fact both possible to convert - and run successfully.

As such, it works superbly as a flag-carrier to prove that if this project can be converted, so can any other! It will help to start to change the heating industries mindset of what is achievable with renewables and that will have a positive knock-on to more typical properties.

The project's architects (whose offices are based on-site) contacted H2ecO who are located about 20 minutes away to see what could be done.

Many options were considered, modelled and rejected, including River Water-source heat from the river that runs through the property, wind power, full ground source heating system with ground arrays, open and closed Boreholes etc.

Eventually, after planning discussions, an agreement was reached to allow for a 100kWp ground mounted array of Solar Panels in an attached meadow and a 25kWp array of Solar Panels in a service area. These were the maximum area of panels allowed after Planning and grid application limitations.

The Grid connection was upgraded to 3 phase to allow for the renewable equipment to be connected and to improve the reliability of the local grid connection. The cost of this formed a significant part of the overall project cost but was considered as an investment in the long term future of the site - and was needed to facilitate the various generation and heating technologies.

The generator was replaced with 3 x Tesla powerwall Battery storage systems and another 9 Tesla powerwalls were installed to allow time-shifting of the SolarPV energy and assist with grid balancing to help the National Grid decarbonise.

Heating was eventually managed with a large ground collector array in an adjacent 3 acre meadow. This was connected to the holiday rental cottage which has its own GSHP from Kensa. The "Coach House" reception and events building was across the river from the meadow so the ground collector header pipes had to be run across the river to reach the new coach house plant room. This was achieved by directionally drilling under the river with attendant environment agency permitting and trenching through formal gardens.

The coach house is now heated and has DHW provided by 3 x 15kW Kensa GSHPs.

The manor house was a particularly difficult challenge as the property is solid stone, has stained glass windows and has construction elements dating back to the 1400s. It has a total heat loss of approximately 150kW. And in some locations older style radiators had to be retained, precluding the use of low temperature heat pumps. As such, a higher temperature source of heat was required and after discussions with the planners, a bank of 10xDaikin High Temperature heat pumps was allowed in one location and another five in another location some 1050 meters from the building they need to heat. This required the construction of a new small plant room and the installation of a long length of district heating pipe in a trench running through the formal gardens.

One of the key positive factors was these units very low noise output. In practice this has been borne out as the bank of ten heat pumps, when running at full capacity, make less noise than the existing encased fountain pump they are located next to.

In both the coach house and the manor house, the plant room locations have been extremely challenging. Several external parties said it was impossible to fit the required equipment in to the available spaces but by thinking 3 dimensionally, H2ecO and its partners have been able to achieve success.

The manor house has a DHW demand for the newly fitted out accommodation areas that can be rented for weddings etc. four of the HHT heat pumps easily deliver the required heat to the 2x 400 litre quad-coil DHW cylinders.

Interpretation panels are installed at the site so all of the visitors can learn about the project. The site attracts around 25,000 visitors per annum. The project is included in the official guidebook and staff are trained to talk to visitors about the project.

School groups who visit are told about and shown parts of the equipment and have the concept explained.

RESULTS

The first 12 months operational data show that the target energy reduction and carbon emissions are being achieved with all technologies working as expected.

EQUIPMENT USED

Daikin Equipment used

15x Altherma 3 HHT heat pumps

2x sequence controllers and associated comms units in each heat pump

Newark Copper equipment used

1x 500 litre buffer vessel

1x 300 litre buffer vessel

2x 400 litre Unvented quad-coil DHW cylinders

Kensa Equipment used

1x 13kW single phase EVO GSHP

3x 15kW 3 phase EVO GSHP

2x 150 litre buffer vessels