Air source heat pumps use refrigerants to help them convert heat energy from the air outside and use this to provide heating to our homes. For the last number of years, R32 refrigerant has been commonly used in heat pumps and as heat pump technology has evolved, the type of refrigerant used in some heat pumps is also changing. Let’s take a closer look at R290 refrigerant and the role it plays in home heating.
Air source heat pumps are helping to decarbonise home heating and are an important feature in the future of low carbon heating solutions. Within every heat pump, there is refrigerant gas which plays an important role in the operation of a heat pump, enabling the production of functional heat that can bring warmth to the rooms in your home and provide hot water. Different refrigerants are used in heat pumps, including R32 refrigerant, and as with any refrigerant gas, these can have an impact on the environment, specifically on the ozone layer. Some refrigerant gases have less of an environmental impact than others and legislation has encouraged the move towards these more environmentally friendly refrigerants, such as R290.
What is R290 Refrigerant used for?
R290 refrigerant gas is a natural hydrocarbon and is better known as Propane. Widely used in air conditioning systems and refrigeration, the use of R290 in low carbon air source heat pump systems is now also increasing. R290 refrigerant is non-toxic, odourless and has excellent thermodynamic properties which means that it can absorb heat energy efficiently from the air (when in a gas state) and transfer this to the wider heating system (when it cools into a liquid state). In addition to being highly energy efficient, R290 refrigerant is also more sustainable compared to other refrigerants.
Inside a heat pump, R290 refrigerant is used the same way as R32 refrigerant with the refrigerant entering a cycle of changing from a liquid to a gas and back to a liquid. In the evaporator, where the air is drawn into the heat pump, the R290 refrigerant is exposed to the air where the refrigerant boils off to a gas and absorbs the latent heat energy from the air. As a gas, the R290 refrigerant is them compressed (in the heat pump’s compressor) where the heat content is increased further before the gas passes through the heat exchanger. At this point, the R290 gas condenses back to a liquid and it transfers its heat to the water in the heating system before re-circulating and repeating this cycle.
Benefits of using an R290 heat pump
As well as being more environmentally friendly, R290 refrigerant offers a range of additional benefits to heat pumps including exceptional efficiencies and low noise levels.
- Good for the environment
Every refrigerant gas has a GWP (Global Warming Potential) value which represents the amount of time a gas remains active in the atmosphere and its impact on warming the atmosphere during this time. For example, R410a refrigerant, which was used in heat pumps several years ago, had a GWP of 2088. In comparison R32 refrigerant has a GWP of 675, while R290 refrigerant (a natural refrigerant), has a very low GWP of only 3 and is therefore deemed to be more environmentally friendly than other refrigerants – one of the reasons why its use in heat pumps is increasing.
- Efficiency
R290 refrigerant has excellent thermodynamic properties which enables it to capture heat energy and release it again very effectively within a heat pump, which makes the system very efficient. As a result, the Grant Aerona 290 has achieved an ErP energy rating of A+++ at 35°C flow temperature.
- Noise levels
The acoustics of a heat pump are very important because air source heat pumps are located outdoors, and therefore must not be a nuisance to those living in the home or neighbouring properties. This is why the Grant Aerona 290 heat pump has been designed to operate with ultra-low noise levels. Heat pumps within the range have also been recognised by the Internationally acclaimed Quiet Mark accreditation.
R32 vs R290 – a comparative look
As mentioned above, one of the main differences between R290 refrigerant and R32 refrigerant is their GWP values – the GWP of R290 is 3 and the GWP of R32 is 675. R32 is a type of F-gas and R290 is a type of natural refrigerant. While R290 is more flammable than R32, both refrigerants have low toxicity levels. Both are energy efficient but R290 refrigerant is considered to be more efficient. R290 refrigerant evaporates at a slightly higher temperature compared to R32 and it has a lower condensing temperature as well.