Hot summer days are often a welcomed sight. However, temperature records are being broken worldwide, which experts say is being fueled by the climate crisis and poses a significant risk to human and planetary health as well as the future of the planet.
Moreover, as the days get hotter and hotter, the use of air conditioning systems will likely rise, which is a threat to the environment due to their high energy consumption and increased warming potential of the refrigerants used.
A recent study led by the International Institute for Applied Systems Analysis (IIASA), Austria, however, suggests that the secret to greener air conditioning could lie in using propane, a clean-burning alternative fuel, as a refrigerant.
The study published in Proceedings of the National Academy of Sciences of the United States of America (PNAS) was led by Pallav Purohit of the IIASA together with the United Nations Environment Programme and researchers from the University of Leeds.
Propane exhibits significant environmental advantages through good energy performance and a global warming potential of less than 1. In split-ACs up to 7 kW, propane can be classified as a technically valid alternative to HFC-driven split-ACs.
Pallav Purohit, IIASA
The team demonstrated that by using propane as an alternate coolant in air conditioning systems, there is the potential to prevent a 0.09 °C increase in global temperature, which could mean keeping any future rise in global temperature below 1.5 °C.
Low Global Warming Potential
The team applied IIASA’s GAIN model to study hydrofluorocarbon (HFC) emissions in the split-AC sector and assessed the differences between using conventional refrigerants such as fluorinated gases (F-gases) and propane which has a low global warming potential (GWP).
Yet, one of the drawbacks of using propane is that there is a greater risk of flammability due to safety standards and regulations, which is holding back the widespread acceptance of this clean-burning alternative fuel.
Nonetheless, the European Commission is drawing up proposals that may herald a ban on using HFCs with high GWP (>150) and even proposing a total ban on F-gases in new systems and devices. The package of measures aims to prevent emissions equivalent to 40 MtCO2e by 2030 and 310 MtCO2e by 2050.
While energy-efficient propane-based air conditioning systems are being rolled out in Chinese and Indian markets, a lift on current bans and regulations would be required to see a global adoption of propane as an alternate refrigerant.
Methods are being developed to use blended HFCs with lower GWP. Using the IIASA GAIN model, Purohit and his team were able to report that this would reduce greenhouse gas emissions from split-ACs by around 44% by the year 2100.
However, using propane, this figure doubled to a reduction of around 88% in the same period.
To achieve the EU’s ambitious 2050 climate neutrality targets, early and aggressive action is needed. In the short term, converting new air-conditioning systems to more environmentally-friendly refrigerants can reduce their climate impact significantly, underlining the urgency of updating standards for policymakers.
Pallav Purohit, IIASA
The researchers claim that using propane would not only cause a significant reduction in greenhouse gas emissions but also make the energy consumption of air conditioning systems – such as HVAC - more efficient in the long term.
Therefore propane could have a key role in reducing global greenhouse gas emissions as hotter summers mean increased reliance on air conditioning in both commercial and domestic indoor spaces.
References and Further Reading
Purohit, P., Höglund-Isaksson, L., Borgford-Parnell, N., Klimont, Z. and Smith, C., (2022) The key role of propane in a sustainable cooling sector. Proceedings of the National Academy of Sciences, [online] 119(34). Available at: https://www.pnas.org/doi/10.1073/pnas.2206131119
IIASA - International Institute for Applied Systems Analysis. (2022) Propane — a solution for more sustainable air conditioning. [online] Available at: https://iiasa.ac.at/news/aug-2022/propane-solution-for-more-sustainable-air-conditioning
Climate Action. (2022) EU legislation to control F-gases. [online] Available at: https://ec.europa.eu/clima/eu-action/fluorinated-greenhouse-gases/eu-legislation-control-f-gases_e