Using carbon dioxide (CO2) as a refrigerant began in early industrial times and has been revived in the past couple of decades.
But what is CO2 refrigeration? And why is CO2 a good thing when it comes to refrigeration? It is, after all, common knowledge that CO2 emissions from from fossil fuel consumption are one of the main drivers of climate change.
CO2 and all other refrigerants used in air conditioning, heat pumps and refrigeration systems have been given a Global Warming Potential (GWP) value. The GWP explains the magnitude of its effects on the climate over a period of time, traditionally 100 years. As the main greenhouse gas, CO2 — also called R744 when used as a refrigerant — has been given a GWP value of 1. This is to make comparisons between different refrigerants easier.
So why is CO2 refrigeration a good thing?
This becomes apparent when looking at synthetic refrigerants promoted by the chemical industry. These have GWPs that, in many cases, are thousands of times higher. Two of the most popular synthetic refrigerants around the world, currently, are called R410A and R32. R410A has a GWP of 2,100 and R32 has a GWP of 771, calculated over a period of 100 years. In other words, R410A’s GWP is more than two thousand times higher than R744’s, meaning that while CO2 that escapes from cooling or heating equipment does have a small impact on the climate, the alternatives are thousands of times worse.