The Design and installation of a low carbon heating system

• The Council’s main offices extend to approximately 50,000 square feet and are occupied primarily as office accommodation between 08:00 and 18:00, Monday to Friday, with some out of hours use.
• The building is of traditional construction with stone walls, steel frame elements and extensive glazing. The roof structure comprises timber purlins with slate coverings, alongside glazed atria and areas of flat roof.
• Heating is currently provided by a series of gas fired boilers (installed within the last five years) serving a wet central heating system comprising a primary distribution loop feeding smaller bore pipework and conventional radiators throughout the building.
• There is a central air handling unit serving two large atria.
• Local air conditioning units serve some meeting rooms, the council chamber, and critical areas including the server and network rooms which operate continuously.
• Hot water is predominantly generated by local electric water heaters.

Existing Energy Infrastructure

• In 2024 the Council installed a 150 kW solar PV array alongside approximately 180 kWh of battery storage.
• Annual electricity generation from the array is approximately 145,000 kWh.
• Grid electricity consumption is approximately 205,000 kWh per year in addition
• Gas consumption is approximately 425,000 kWh per year.
• Heating demand is strongly occupancy driven, with peaks of approximately 28–34 kW during morning warm up periods and typical daytime loads between 16–24 kW.

Project Aim

• The Council is seeking to significantly reduce its reliance on gas and improve the environmental performance of the building.
• This engagement will help explore viable options for the deployment of heat pump technology and associated system upgrades.
• The Council is open to a range of approaches and is seeking a design led solution tailored to the building and its operation as well as the existing plant infrastructure in place.

The Council is interested in proposals and input relating to:

• Air source and ground source heat pump systems
• Hybrid systems integrating with existing gas boilers
• Low temperature heating strategies and retrofit solutions
• Modest fabric improvements where appropriate
• Integration with existing solar PV and battery storage
• Control strategies to optimise system performance

The Council is particularly interested in solutions which minimise disruption and make effective use of existing infrastructure where appropriate.

The Council invites interested parties to provide information including:

• Outline of proposed technical approaches
• Indicative capital costs
• Expected operational savings
• Carbon reduction estimates and payback periods
• Programme and delivery considerations
• Key risks, constraints and assumptions

The Council is particularly interested in understanding both financial and carbon payback metrics.