Refra Hydrocarbon Heat Pumps Power 1.6 MW Low-Carbon Energy Centre in UK

Solihull town centre’s low carbon energy network © 2025 Solihull Metropolitan Borough Council

Solihull, a town in the West Midlands of United Kingdom, has taken a major step toward decarbonizing its heating infrastructure with the installation of six Refra hydrocarbon heat pumps for a new 1.6 MW Energy Centre. The project will deliver district heating and hot water to local government buildings, community facilities, and educational institutions, significantly reducing carbon emissions in line with the Council’s net zero 2041 target.

The installation, part of Solihull’s low-carbon energy network, features five air-to-water propane heat pumps (R290) and one water-to-water isobutane heat pump (R600a) manufactured by Refra. The hybrid configuration delivers hot water at up to 80°C, enabling seamless integration with the existing high-temperature heating network.

Each of the R290 heat pumps provides a heating capacity of 171.6 kW and a cooling capacity of 169.8 kW, achieving a COP of 4.64. The R600a unit delivers 1.7 MW of heating and 1.3 MW of cooling with a COP of 4.48. Absolutely Chilled, an official distributor of Refra in the UK, estimates that upon completion of the third and final phase, the new energy center with hydrocarbon heat pumps has the potential to avoid over 6000 metric tons of CO2e emissions annually.

Installation process of Refra Hydrocarbon Heat Pumps © Absolutely Chilled

Funded in part by a £9.6 million loan from the UK Government’s National Wealth Fund, the project is being delivered in partnership with sustainable heat infrastructure specialist Vital Energi. More than 5 km of underground piping has already been laid to connect buildings to the network, which will be fully operational by spring 2026, with capacity for future expansion.

“Heating is the biggest contributor to the UK’s carbon footprint,” said Councillor Andy Mackiewicz, Cabinet Member for Climate Change and Planning. “The air source heat pumps at the heart of our energy centre will play a major role in delivering cleaner energy where it’s needed most.”

While CO2 and ammonia are more common natural refrigerants in district heating, Solihull’s adoption of hydrocarbon heat pump technology demonstrates growing confidence in R290 and R600a as efficient, sustainable alternatives. This innovative project positions Solihull as a leader in low-carbon district energy, offering a model that could be replicated in other UK towns and cities.

System specs

Propane Heat Pumps
Manufacturer: Refra
Model: Non-standard Solis Heat Pump (5 units)
Heating/Cooling source: Air-source
Refrigerant: R290 (propane)
Refrigerant charge: 48 kg per unit
Total cooling capacity: 849 kW (169,8 kW per unit)
Total heating capacity: 858 kW (171,6 kW per unit)
Compressors: Bitzer
Controller: Siemens

Isobutane Heat Pump
Manufacturer: Refra
Model: Non-standard Water to Water Heat Pump
Heating/Cooling source: Water-source
Refrigerant: R600a (isobutane)
Refrigerant charge: approx 119,62 kg
Total cooling capacity: 1184,2 kW
Total heating capacity: 1672,78 kW
Compressors: Bitzer
Controller: Siemens

Hydrocarbon Heat Pumps at Refra factory © Ilona Brant Pavšukova