By 2050, 3.7 billion air conditioners are expected to be in use, fueling global warming. We can avoid this by using propane as a coolant.
By using propane as a refrigerant in air conditioners, about 0.1 degrees Celsius can be prevented by the end of the century. That would be a significant reduction, given that from now on the planet should not warm more than about 0.3 degrees to meet the target of the Paris agreement. According to this target, total global warming compared to pre-industrial levels must be limited to 1.5 degrees.
In 1987, most countries decided to replace the ozone-depleting gases in refrigeration equipment with so-called hydrofluorocarbons (HFCs). HFCs do not harm the ozone layer, but they are potent greenhouse gases. Some even have a thousands of times greater effect on global warming than CO2.
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More than 100 countries have now decided to replace HFC refrigerants to reduce emissions from the refrigeration sector. That sector is currently responsible for about 7 percent of global greenhouse gas emissions. If emissions remain as they are now and global warming continues, that percentage could even double by 2030, says refrigeration scientist Toby Peters from the University of Birmingham.
Three scenarios
environmental scientist Pallav Purohit of the International Institute for Applied Systems Analysis in Austria and his colleagues examined the effect of replacing HFCs with propane in the most commonly used air conditioners, the so-called split ACs. A ton of propane has a smaller warming effect than a ton of CO2Purohit said.
The researchers used climate and economic models to compare three scenarios. In the first scenario, powerful HFCs are still used. In the second, the most commonly used HFC is replaced by an HFC that leads to less warming, but still has hundreds of times the effect of CO2. In the third scenario, all split ACs use propane as the refrigerant.
The research showed that rapid switching to propane by 2100 would prevent a warming of 0.06°C to 0.12°C. The researchers assumed a future in which the CO2emissions will remain at approximately current levels until 2050 and then begin to decline. Switching to the less potent HFCs would reduce warming by 0.03°C.
Flammable
According to HFC expert Alex Hillbrand According to the Natural Resources Defense Council, a US environmental organization, 0.1 degrees less warming would be a ‘huge deal’. It is almost half of what we want to achieve by reducing the use of HFCs by 80 percent by 2047. But large-scale adoption of propane is a challenge, Hillbrand says, especially for countries like India and China where demand for refrigeration is growing rapidly.
Until now, most manufacturers have opted to switch to less potent HFCs because that option is better known than propane, Hillbrand says. Propane air conditioners are available in Europe and Asia, but they are only a small part of the current market. Elsewhere they are banned because propane is flammable.
It is expected that 3.7 billion air conditioners will be in use by 2050. According to Peters, it would be good if more of them used propane. But since 80 percent of emissions related to refrigeration come from generating the electricity to power refrigeration appliances, more energy-efficient refrigeration and clean energy sources are also needed. Furthermore, other climate-friendly refrigerants such as ammonia may be more suitable for certain locations and applications.