A major UK airport has taken its first step towards net zero by replacing gas-fired heating with a high-temperature 400kW air source heat pump system. Installed to operate at 75/60°C flow temperatures, this retrofit solution provides immediate operational benefits while supporting the site’s long-term carbon reduction goals.
Immediate Impact Without Disruption
The airport handles both domestic and international flights and has set clear sustainability targets. To support these objectives, two 200kW OHT air source heat pump units have been installed as the site’s new primary heat source. The key requirement was to deliver high-grade heating at existing system temperatures, without the need for immediate changes to the current heating distribution infrastructure.
The selected OHT heat pumps can supply flow temperatures up to 80°C, making them well-suited to replace traditional gas boilers in legacy low-temperature hot water (LTHW) systems.
Designed for Retrofit and Future Flexibility
This project highlights a practical route to decarbonisation through heat pump technology, particularly in complex commercial sites where full system upgrades are not immediately possible.
The initial design maintains existing emitters, delivering 75°C flow and 60°C return temperatures to meet building demand. As the airport undergoes further building refurbishments over the coming years, lower temperature emitters will be introduced to further improve system efficiency. The heat pump setup has been designed with this staged transition in mind.
The system includes:
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2 x OHT 80-205 Air Source Heat Pumps
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4 x independent compressors across 4 refrigeration circuits
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2 x 2,000-litre stratified integration vessels
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Design operating conditions: 75/60°C at -5°C ambient
These components ensure efficient heat delivery and load management, helping to maintain heating performance even during cold weather conditions.
Resilience and Efficiency in Demanding Environments
Airports present unique operational demands. Heating systems must run reliably throughout the year, particularly in passenger-facing and critical areas. This project ensures thermal resilience through the use of dual high-performance heat pump units, supported by buffer vessels for stability and responsiveness.
The integration tanks allow the heat pumps to operate in a steady and efficient manner, even when demand fluctuates. This ensures smooth operation across a range of conditions and supports long-term reliability—key for such an essential infrastructure environment.
Replacing Gas Without System Changes
One of the standout features of this project is the ability to replace gas heating without modifying the wider distribution system. By matching the existing LTHW system temperatures, the OHT heat pumps could be introduced without delay or disruption.
This approach makes high-temperature heat pumps a viable option for many commercial buildings, particularly those where legacy systems, capital budgets, or operational constraints make full upgrades difficult.
A Platform for Decarbonisation
This installation marks a key step in the airport’s transition away from fossil fuels. The new heat pump system provides the foundation for further decarbonisation measures, including the future optimisation of heat emitters and control strategies.
By adopting high-temperature heat pump technology early, the site benefits from:
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Immediate carbon reduction
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Elimination of gas usage in core areas
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Scalable infrastructure for future upgrades
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Improved energy efficiency without disruption
Summary
With the installation of this 400kW high-temperature air source heat pump system, the airport has successfully delivered a practical, high-impact decarbonisation project. This retrofit shows how organisations with older infrastructure can still make significant progress towards sustainability goals using well-designed, technically capable heat pump systems.
The flexibility of the OHT system, combined with robust integration design, enabled the project to displace gas boilers from day one—without needing major alterations to the existing heating network.
This is a clear example of how heat pumps can deliver long-term value in commercial and public infrastructure, setting the stage for broader energy transition programmes.