Vaillant: Critical gas for heat pumps

The decarbonisation of UK heat has never been higher on the agenda. Whilst no single technology can serve as a sole solution to the climate crisis, it is widely agreed that heat pumps will play a significant role in the battle to meet net zero carbon by 2050. Craig Dolan, product manager for renewable systems UK at Vaillant Group, explains why there’s more to heat pump efficiency than meets the eye.

Significantly cleaner and more efficient than traditional fossil fuel boilers, heat pumps have long been a central part of the decarbonisation conversation. Once a fringe product, the growing emphasis on emissions reduction, both at a government level and in the public eye, have brought these technologies into the mainstream.

However, whilst it is commonly understood that heat pumps are a green solution, there is little awareness around the differing environmental impacts and operating efficiencies of the various refrigerants in use within heat pumps on the market today.

Historically, the most commonly used heat pump refrigerant was R410A, but due to its high Global Warming Potential (GWP), it is currently being phased out of the market under the f-gas regulation. At present, many heat pump manufacturers are either using, or planning to use, R32, as an alternative.

However, whilst R32 is undoubtedly a greener solution than R410A, the likely level of growth for the heat pump market means that it will be unacceptable under f-gas standards by as early as 2024-26.

So what is the solution? Natural refrigerants and hydrocarbons offer not only higher efficiencies but greener operation and overall lifecycle.

For starters, the GWP of R32 is 675, a marked reduction from the 2088 of R410A, but enormously higher than the GWP of 3 which some natural refrigerants can claim. What’s more, heat pumps which utilise natural refrigerants can use less volume per kW, allowing them to achieve the same, or greater results than counterparts, more efficiently.

Looking at refrigerant from a lifetime perspective, not only can natural options provide the above operational benefits, they will also have less environmental impact when the time comes to recycle the heat pump, as the exposure of the refrigerant will be much less damaging due to its extremely low GWP.

From the perspective of efficient provision of heat and hot water, natural refrigerant can yet again offer a major advantage, as it allows higher temperatures in the heat pump. With that in mind, a heat pump using natural refrigerant could conceivably offer performance similar to that of a boiler, but with the zero emissions at point of use benefits inherent to heat pump technology. This also means that heat pumps using natural refrigerant could potentially be retrofitted without significant change to an existing heating system, bringing down the capital cost of installation.

Whilst this would make heat pumps a more affordable option, it’s worth mentioning that, when installing any new heating system, reasonable steps should be taken to ensure the system is sized correctly and heat loss is reduced. After all, the golden rule for all heating systems is the lower the flow temperature, the more efficient the system, consequently providing lower running costs and greater comfort.

Certain manufacturers are already beginning to incorporate natural refrigerants into their products. In fact, as part of our continuous effort to improve efficiencies and reduce emissions, Vaillant has begun to develop and release such products. Our aroSTOR hot water cylinder, for example, uses a natural refrigerant with an extremely low GWP and outstanding performance, this refrigerant will likely be used in relevant future products, too.

Heat pumps will undoubtedly play a substantial role in the decarbonisation of the UK, and it’s important that they are specified in suitable environments, to ensure they offer the right level of performance as well as efficiency. When it comes to heat pump specification, it’s vital to consider the impact that the type of refrigerant used will have on the performance of the heat pump and the heating system. Natural refrigerants and hydrocarbons provide a low carbon, low running cost solution, with minimal environmental impact at end of life. And, looking to the future, if these refrigerants, when paired with the right technology, can offer performance akin to a gas boiler, and significantly reduce the cost of retrofit, they could revolutionise the way that we look at heat pumps.