Milton Keynes approves low-carbon heat network works

Milton Keynes City Council has approved a contract with FairHeat to prepare three public buildings for connection to a low-carbon heat network, moving the programme from procurement into building-level delivery.

The Civic building, Central Library, and Woughton Leisure Centre are included in the contract. The programme is backed by £4.35 million secured through the Government’s Public Sector Decarbonisation Scheme and is intended to reduce reliance on individual gas-fired heating systems.

The latest contract concerns work inside and around the three buildings rather than construction of an entire city heat network. Existing properties generally need plant-room alterations before they can accept heat from a common distribution system, including changes to heat exchangers, pumps, controls, metering, and building-management systems.

Those interfaces can determine whether a heat network performs efficiently once connected. A building whose internal heating system requires high flow temperatures or returns water to the network too warm can reduce the temperature difference available across the wider system and increase both pumping requirements and distribution losses.

Engineers therefore need to establish the actual heat demand and operating temperatures of each property rather than simply replacing its existing boiler connection. Radiators, air-handling coils, domestic-hot-water equipment, pumps, and control valves may all need to be assessed against the temperatures expected from the future network.

The three buildings also have different operating profiles. Woughton Leisure Centre has substantial leisure and hot-water loads, while the library and Civic building are more closely linked to occupancy and office hours. Peak heat requirements and daily load shapes will therefore differ even though all three properties are intended to connect to the same system.

The council has previously examined Milton Keynes Waste Recovery Park as a potential source of heat for a wider network. The facility processes non-recyclable municipal waste and produces electricity while rejecting heat that could potentially be recovered and upgraded for use in nearby buildings.

Council programme documents describe an approach in which low-grade heat from the Waste Recovery Park could be transferred to an energy centre, upgraded using water-source heat pumps, combined with thermal storage and pumping equipment, and then supplied into a distribution network.

That architecture shifts much of the heating infrastructure away from individual boilers. Heat production or recovery, heat pumps, thermal storage, pumps, controls, and buried distribution pipework become shared assets, while individual buildings require substations or heat-interface equipment capable of accepting and metering the delivered energy.

The first three public buildings can provide anchor demand for that infrastructure. Large municipal sites offer more predictable heat consumption than a collection of small domestic customers and can help establish an initial load profile while a wider network is developed around them.

Expanding the scheme beyond those buildings would still require additional heat sources, distribution pipework, customer connections, metering, and commercial agreements. Thermal networks also have to maintain acceptable temperatures and pressure across varying distances and demand conditions, making hydraulic design increasingly important as the number of connected properties grows.

Electrical demand remains part of the system even though the product delivered to buildings is heat. Circulation pumps, controls, metering, energy-centre equipment, and any large heat pumps used to raise water temperature all require electricity, while thermal storage can help shift some of that electrical consumption away from peak periods.

The performance of the building connections will consequently influence the power requirement of the wider heat system. Lower network temperatures can improve heat-pump efficiency, but only where building emitters and hot-water systems can operate effectively at those temperatures. Poor building-side performance can force higher supply temperatures and increase electricity consumption at the energy centre.

Commissioning will need to verify the interaction between existing heating systems and the new network interfaces. Flow rates, return temperatures, control sequences, metering, alarms, and building-management-system integration have to work under changing loads rather than only during a static handover test.

Operational data from those first buildings can then inform later phases. Heat meters and controls can show how closely actual demand follows the design assumptions and identify high return temperatures, unexpected peak loads, or control problems before similar interfaces are repeated across a larger number of customers.

The £4.35 million programme does not create a complete city-wide network on its own, but it addresses one of the practical prerequisites: preparing sizeable existing buildings to receive low-carbon heat. With the FairHeat contract approved, the project moves into the detailed plant-room and controls work that will decide whether the eventual network can deliver its heat efficiently once the distribution infrastructure reaches the buildings.