Tyneham heat pumps provide underfloor heating for St Mildred's Church

Sector: Historic buildings and churchs

Building: St Mildreds Church

Products: 2 x 27kW Tyneham 290HT air source heat pumps

Application: Underfloor heating

St Mildred’s Church in Tenterden, Kent, is undergoing a major project to transform the historic building to meet the needs of the 21st century, while ensuring it continues to play an important role at the heart of the local community. As part of the project, two Tyneham heat pumps have been installed to provide underfloor heating across the majority of the Nave.

Dating back to the 12th century, St Mildred’s is a Grade I listed Church of England parish church. It remains a busy community building, hosting regular services, functions and activities throughout the week, while a church hall is also available to hire for events and private functions. With the building in regular use, the church needed a comfortable and reliable heating system for congregants.

Replacing an ageing heating system

The church’s previous heating system consisted of an ageing cast iron gas-fired boiler serving a single-pipe system with cast iron radiators. As part of the project, the existing system was upgraded to provide improved thermal comfort while supporting the church’s sustainability objectives and the need to protect its historic fabric. With the Church of England’s target to reach Net Zero by 2030, sustainability was a key consideration when assessing the options for the new heating system.

As part of early-stage feasibility work, an options appraisal to identify a suitable approach for the building was undertaken by PCS Consulting Services. Following this assessment, underfloor heating was selected as part of the new system. This decision was based on the fact that it provided a good match for low temperature heating while helping to create a more consistent internal environment. It also offered benefits for the protection of the church fabric.

A hybrid heat pump solution

To provide the required heating capacity, two 27kW Tyneham 290HT air source heat pumps were specified in a cascade arrangement. The heat pumps operate as the primary heat source in a bivalent system, working alongside a third party gas fired boiler through a common buffer arrangement.

The underfloor heating covers the majority of the nave, with additional radiators retained in the chancel. Finned tube heating has also been installed in trenches at the base of the north and south nave walls to help mitigate cold down draughts from the windows. During periods of peak use, the system temperature can be increased to enable effective heat transfer from these emitters.

This combination of heat pumps and underfloor heating provides a good match for the building’s low temperature heating requirements. The hybrid arrangement also allows the gas boiler to provide additional heat during colder external conditions, with the heat pumps taking the primary load during milder, mid-season conditions. The decision to specify Hamworthy Tyneham heat pumps was based on a number of factors, including their temperature profiles and seasonal coefficient of performance (SCOP).

Adam Rawlinson, Director & Chartered Engineer at PCS Consulting Services, comments:

“The 27kW Tyneham R290 heat pumps were a good fit for the project, particularly given the low temperature requirements of the underfloor heating and the church’s varied pattern of use. The support from the Hamworthy team was also important throughout the specification process, with good access to product information and technical advice when required.”

Installed by Grummant Heating and Services Limited, within a custom external plant compound next to a new plant room in the churchyard, the heat pump installation formed part of an approximately nine-month programme of works, which also included extensive flooring replacement, joinery and redecoration. BMS controls were also installed to manage the hybrid changeover points and pump control, while also providing an interface for the client.

Designed around the building

Now approaching a year in operation, the system has been carefully monitored by St Mildred’s Church, with operation and comfort reportedly excellent. During mid-season conditions, the heat pumps provide the primary heating load, while the gas boiler supports the system during the coldest external conditions.

Following a successful installation, St Mildred’s Church now benefits from an efficient low temperature heating solution which helps to deliver comfortable temperatures while supporting its sustainability objectives.

For more information on our range of heat pumps and hybrid heating solutions, contact your Area Sales Manager.