The ultra-low global warming potential (GWP) heat pump solution provided by Carrier for E.ON's Citigen energy network serving the city of London is anticipated to reduce carbon emissions from heating and cooling up to 50%, and will enhance air quality in the city by reducing emissions.

The project has earned Project of the Year 2022 status during the ACR News Awards 2022. Three Carrier AquaForce 61XWHZE high-temperature heat pumps operating on hydro-fluoro-olefins (HFO) R-1234ze refrigerant extract thermal energy from water pumped from deep boreholes in the aquifer 200 m beneath Source: Carrierthe capital. The heat pumps also harness waste heat from the existing combined heat and power plant that would otherwise be lost to atmosphere.

The heat pumps provide up to 4 MW of heating and 2.8 MW of cooling to residential and business customers via a district-wide network of highly insulated pipes, running underground for 10 km. Customers connected to E.ON’s heating and cooling network include the Barbican arts and residential complex, the Guildhall and the Museum of London.

The project is part of a multi-million-pound program by E.ON to improve and upgrade the Citigen energy center, supporting efforts to decarbonize the city and transform how connected buildings in the Square Mile are heated and cooled. The refrigerant used in the selected heat pumps, R-1234ze, has a GWP of less than 1, significantly lower than the previous refrigerant, and therefore has only a tiny fraction of the environmental impact.