Heat Pumps: Refrigerants Bare All And Go Au Naturel

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Heat Pumps: Refrigerants Bare All And Go Au Naturel

As organizations announce net zero pledges, one approach to reducing operational carbon emissions is through switching to heat pumps and removing reliance on fossil fuels. Heat pump adoption continues to rise globally thanks to energy price volatility and energy insecurity. Three million heat pumps were sold in Europe in 2022, while in North America sales of heat pumps overtook gas furnaces for the first time.

However, not all heat pumps are created equal. Refrigerants used in heat pumps are typically a large source of embodied carbon emissions over the product’s lifespan, as they leak into the atmosphere producing a warming effect of a magnitude exponentially greater than carbon dioxide. Global warming potential (GWP) is utilized to illustrate the warming effect of refrigerants. For example, refrigerant R410A, which is the main type used in heat pumps, has a GWP of 2,088 – as such, 1kg of R410A has the same warming effect as 2088kg of carbon dioxide.

The world is aware of the damage refrigerants can inflict on the planet. In the late 20th century, the CFC and HCFC families of refrigerants were found to be eroding the ozone layer above Antarctica and the global community acted. The Montreal Protocol, adopted in September 1987, banned the use of over 100 manmade ozone-depleting substances and the ozone layer has been able to heal; it is estimated that by 2030 two million people per year will be saved from skin cancer. Further global action has occurred in recent years with the Kigali Amendment of 2019, which seeks to reduce and ban the use of HFC refrigerants. HFCs, despite not being ozone-depleting, have large GWPs and thus threaten to increase the rate of global warming if usage is unrestricted.

The industry is starting to move away from using high-GWP refrigerants in heat pumps. Carbon dioxide is now being used as a refrigerant in domestic hot water heat pumps, as its properties allow it to produce higher temperatures than typical space heating refrigerants; temperatures produced can be as high as 110°C. Solutions are provided by a range of vendors, such as Cooltherm, Kima-Therm and Mitsubishi Electric. Building owners seek these heat pumps to replace the inefficient direct point-of-use electric water heating present in many commercial properties today. With legislation such as UK Part L 2021 now considering the new Target Primary Energy Rate metric, which evaluates how much primary energy is required for the energy delivered to the end-user, it is important for building owners to find efficiencies wherever possible.

Other low GWP refrigerants are also emerging. Propane (GWP=3) is being utilized in reversible heat pumps to facilitate low embodied carbon heating and cooling. Swegon, a Swedish HVAC manufacturer, recently announced the launch of their Omicron Zero product, one of the first simultaneous heating and cooling units to come to market. Yet, propane as a refrigerant presents challenges to building managers, with a higher level of flammability. Despite the safety concerns, the reduction in embodied carbon compared to typical refrigerants, including R410A and R134A (GWPs 2088 and 1430), is significant. As such, the adoption of these natural refrigerants will rise as heat pump adoption grows.

For further detail on the growth of the heat pump market and key vendors offering solutions please see Verdantix Tech Roadmap: Energy Management Technologies.

This blog post offers additional coverage of commercial heat pumps. For previous coverage, please see Is The Market For Heat Pumps In Commercial Buildings Heating Up?

Harry Wilson

Industry Analyst

Harry is an Industry Analyst in the Verdantix Smart Buildings practice. His research agenda currently focuses on new strategies for energy management and decarbonisation. Harry joined Verdantix in 2023 having previously worked as a Mechanical Engineer at Arup London, where he specialised in the design of net zero facilities in the commercial, science and technology sectors. He holds a M.Eng in Mechanical Engineering from the University of Nottingham.