About this episode
In this short podcast episode, Bryan answers a listener-submitted question about using R-290 as a drop-in refrigerant for R-22 systems. It is NOT safe to use R-290 as a drop-in, but there are some similar properties between the two and some interesting thought experiments within this topic. R-290 is propane, a hydrocarbon that belongs to the family of natural refrigerants. R-22 is an HCFC refrigerant that has undergone a manufacturing/importation phaseout in the USA. They are both single-component refrigerants, not blends. Both of them have similar operating pressures and oil carry. However, the latent heat of vaporization of R-290 is almost double that of R-22, which makes it extremely effective as a refrigerant. The main issue with using R-290 is that it is highly flammable and explosive (A3), and it has very small charges (500 grams). Around 2010, some people started selling R-290 blends as drop-in alternatives for R-22. In theory, that combination would work very well, but it is not a safe or legal option. R-290 is currently used in sealed, self-contained equipment. However, it could be the future, especially if our industry goes for refrigerants with lower GWPs and uses flame-free fittings and tubing cutters. It's also worth noting that A2L refrigerants do not contain R-290 or any other hydrocarbons, but it is possible that the industry will gradually embrace the more flammable refrigerants like R-290. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool . Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium . Subscribe to our podcast on your iPhone or Android . Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android