Charlie Mowbray, Senior Product Manager, Ideal Heating – Commercial
“Heat pumps are a widely suitable and cost-effective solution for decarbonising the UK’s buildings and are vital to delivering Net Zero” states the UK government in its ‘Heat Pump Investment Roadmap – Leading the way to net zero’ published in April 2023. That’s because heat pumps reduce the reliance on fossil fuels, produce zero local carbon emissions, and can be up to 400% more efficient than traditional boilers.
Heat pumps utilise the free energy in the air to heat water, even when that air temperature is as low as -20⁰C. When heat pumps are partnered with a renewable electricity supplier, heat generation is 100% carbon neutral.
The role of refrigerants within heat pumps
In a heat pump, a fan passes ambient air over extremely cold liquid refrigerant. The refrigerant captures the heat from the ambient air and becomes a warm vapour. That warm refrigerant vapour passes through a compressor which produces hot refrigerant and usable heat. The heat in the hot refrigerant is then transferred to the heating and hot water system through a heat exchanger. After the heat is transferred the refrigerant passes through an expansion valve which reduces its temperature, making it really cold again and enabling it to capture heat from the ambient air, continuing the cycle.
The move to natural refrigerants
As we have become more aware of the negative environmental impacts of many of these older refrigerants, such as R407c, R22, R410a and R32, the industry is moving to natural refrigerants in the form of R290 (Propane) and R744 (CO2). These are refrigerants that occur naturally, as opposed to those that are synthetically made. At Ideal Heating Commercial, we have recently expanded our own ECOMOD commercial heat pump range to include natural refrigerants; the new models are ECOMOD 290HT with outputs of 15 – 50kW, and ECOMOD CO2 & CO2Q with outputs of 65-130kW.
But with any change comes apprehension, and misconceptions abound when it comes to natural refrigerant based heat pumps. Let’s look at five of the most frequently misunderstood aspects of natural refrigerants and shed some much needed light.
5 things you need to know about natural refrigerant heat pumps
1: Performance
Natural refrigerants are able to perform better than synthetic alternatives in heat pumps for two key reasons. Firstly, they can achieve higher coefficient of performance (COP), making them more efficient. COP is the ratio of heat produced, relative to each unit of electricity consumed in the heat pump. Secondly, natural refrigerants can produce higher temperatures, making these heat pumps ideal for heating water. Our ECOMOD 290HT, for example, can achieve a maximum flow temperature up to 75°C. That said, designing a heating circuit to 55°C would make the system much more efficient, in line with the most recently published Building Regulations Part L.
- Environment
Refrigerants are allocated a Global Warming Potential (GWP); those with a high GWP are extremely potent greenhouse gases that warm the planet. Older, synthetic refrigerants nearly all have a high GWP, and we expect them to eventually be phased out. R410a, for example, has a whopping GWP of 2088. Compare that to R290 at 3 and CO2 at just 1 and you can clearly see why natural refrigerants are the environmentally friendly option.
- Total cost of ownership
Moving to natural refrigerants is not only good for the planet, but also makes commercial sense now and in the future. Synthetic refrigerants are more expensive than natural ones as the manufacturing process is more complex, and they are subject to the F-gas phase down. As their production declines, high GWP refrigerants will become increasingly scarce and therefore more expensive.
- System design
If the system designer can design a heat pump system which utilises a synthetic refrigerant, then they will have no trouble in doing the same with most natural refrigerant heat pumps. The system design for R290 in particular is straightforward. In fact, a natural refrigerant heat pump system often requires less amendment to the hot water cylinder, as they do not require immersion heaters for anti-Legionella cycles due to the higher temperatures which are achievable.
- Training
As with all refrigerants and heat pump installations appropriate training is required. If the installer has already undertaken heat pump training, then the good news is that no additional training is necessary for fitting R290 heat pumps (although product specific training is always highly beneficial). However, heat pumps that use CO2 have a higher Delta T return temperature, so the system design differs slightly. But it’s not just installers that should invest in heat pump training. Anyone who specifies or wants to understand more about how heat pumps work can benefit from training, including architects. Ideal Heating provides commercial heat pump training free of charge via our Expert Academy training team.
Natural refrigerant heat pumps are undoubtedly the way forward when it comes to commercial heating and hot water. They tick all the boxes, getting us one step forward to that important net zero goal.