Public Sector decarbonisation: delivering domestic hot water with R290 heat pumps
As one of the first public sector installations of our AquaSnap 61AQ R290 range, this project demonstrates how heat pump technology can be deployed as part of public sector decarbonisation programmes in complex, high-demand buildings.
The Project
Delivered within the public sector leisure and community facilities sector, this project involved a council-owned, multi-use public building accommodating leisure facilities and other council services.
The site required a heat pump-based solution for domestic hot water as part of its wider decarbonisation strategy.
As a public sector project, the scheme was delivered under the Public Sector Decarbonisation Scheme (PSDS), with a clear requirement to reduce carbon emissions while maintaining reliable service for a high-usage facility.
The project brought together multiple stakeholders, including a main contractor, a consulting engineer and Carrier as the equipment manufacturer.
The Challenge
The project centred on replacing an existing boiler-based system with a heat pump-based alternative capable of delivering consistent domestic hot water across a complex, multi-use building. Operational continuity was a key consideration. As a live public facility with multiple occupants, including leisure users and essential services, the building had limited shutdown windows. This placed pressure on both programme and installation, requiring a solution that could be delivered and commissioned quickly without disrupting day-to-day operations.
Noise was also a critical factor, with strict requirements set by the council. While the project successfully met these requirements, certain aspects of the acoustic solution were delivered by third parties.
In addition, the project required close coordination between several parties, including the consultant, main contractor, subcontractors and manufacturer. During the design phase, the specification was changed from an alternative manufacturer to Carrier’s 61AQ range at Stage 3, requiring adjustments as the project progressed.
As with many complex projects, there were technical considerations that required careful management. These were addressed proactively through close collaboration and responsive technical support, ensuring that the installation progressed smoothly and in line with project requirements.
Overall, the focus was to deliver a compliant hot water solution designed to meet the client’s operational requirements, while maintaining confidence across all stakeholders.
“As one of the first public sector installations of our 61AQ R290 range, this project demonstrates how heat pump technology can be deployed as part of public sector decarbonisation programmes in complex, high-demand buildings. The project highlights the importance of collaboration between the client, consultant, contractor and manufacturer in delivering the scheme successfully.”
Graham Smith, Carrier's Applied Commercial Director
The Solution
The final solution was based on five Carrier 61AQ 100P air-to-water heat pumps, using R290 (propane) refrigerant. The system was designed specifically to provide domestic hot water for the facility, replacing the existing boiler infrastructure with an electrified hot water solution.
The use of R290 refrigerant was a key element of the design. With an ultra-low global warming potential (GWP) of approximately 0.02, it aligned with the council’s decarbonisation objectives while meeting the project’s operational requirements.
The specification was driven by the consulting engineer, who selected the 61AQ units during the Stage 3 design phase based on their performance and suitability for the application.
A highlight of the Carrier solution is the high level of standard specification, with smart energy metering, low-noise operation and night mode functionality included as standard rather than optional extras. These features allow site operators to control and limit sound levels during specific periods while providing greater visibility of system performance.
Safety was also a key consideration, given the use of an A3 refrigerant. The system incorporates leak detection measures, including an integrated infrared leak detector within each unit. In the event of a refrigerant leak, the system is designed to shut down automatically.
Additional site-level safety features were implemented in collaboration with the contractor, including visual warning systems within the plant area, to monitor safe operation and maintenance.
The system was configured using a lead/lag arrangement across the five units. This approach provides built-in redundancy, allowing the remaining units to respond if one unit is unavailable due to maintenance or fault conditions. This is particularly important for a facility where continuous hot water availability is essential.
Carrier provided comprehensive technical support throughout the project lifecycle, from specification and design development through to delivery, installation and commissioning. Close collaboration with the contractor and installation team resulted in equipment being delivered on time and integrated smoothly into the overall system
The Result
The completed installation replaced the existing boiler system with a heat pump solution designed to provide domestic hot water for the facility and support the council’s decarbonisation objectives under the PSDS programme.
The system was installed and commissioned in accordance with the project programme and achieved practical completion as planned.
Looking ahead, the system will continue to be supported through ongoing monitoring and optimisation. A service agreement is currently in development, which will utilise Carrier’s cloud-based platform to provide real-time performance data, energy usage insights and predictive maintenance capabilities. This will allow the client to monitor operational performance and energy usage over time.
As one of the first public sector specifications of the 61AQ R290 range, the project may provide useful experience for similar heat pump applications in the future. It demonstrates the application of heat pump technology within a complex, high-demand environment, supported by collaboration between the project partners.
Find out more about Carrier’s decarbonisation products and solutions here: HVAC Decarbonisation Solutions: Achieve Net Zero. You can also email us at uk.info@carrier.com or contact one of our Experts.
