Our post this week is courtesy of Denis Livchak from Frontier Energy. Denis is a refrigeration expert, and in his post below he explains the different types of refrigerants used in refrigeration systems, and why it's so important to pay attention to refrigerants.
All refrigeration equipment contains refrigerant. Refrigerant is a substance that cools down the inside of the fridge or freezer by changing from gas to liquid and vice versa during a refrigeration cycle. Although there are several properties of refrigerants, from an environmental perspective the most important ones are global warming potential (GWP), ozone depletion potential (ODP) and flammability. Why are ODP and GWP so important if the refrigerant stays inside the refrigeration system? Because refrigeration systems leak. These leaks may occur through refrigerant piping contraction/expansion at different welds. through system recharging, or during disposal.
Federal regulations have tried to minimize global warming and ozone depletion through mandating refrigerants that are more environmentally friendly with low GWP and ODP potential. Older refrigerants that are currently being phased out include R12 (also known as freon) and R22. These refrigerants have GWP values of 10,900 and 1,810 and ODP values of 0.82 and 0.06, respectively. The rule of thumb with GWP and ODP values is the higher the number, the worse it is for the environment. Nowadays these refrigerants are quite rare. Most modern refrigerants are zero ODP, however refrigeration units older than 20 years may still use R12 or R22. Most modern lab-grade freezers use R404A refrigerant, which has a GWP of 3,920. Ultra-low temperature freezers also use R508B as the secondary refrigerant, which has a GWP of 13,396.
Natural refrigerants are the most environmentally-friendly option. Natural refrigerants include propane (R290), CO2 (R744) and ammonia (R717), and all have zero ODP and almost zero GWP. So why are we not using natural refrigerants in our equipment? There are drawbacks to each of the three: propane is flammable, CO2 requires very high pressure piping, and ammonia is poisonous. With technological advancements, refrigeration engineers have been able to minimize the risks associated with each type of refrigerant. The most prevalent natural refrigerants in laboratory refrigeration are propane (R290), and ethane (R170) for ultra-low temperature applications. By using small quantities of refrigerant, manufacturers have been able to minimize the potential flammability of the system while drastically reducing the global warming potential of refrigeration systems. Manufacturers are also required to perform safety testing to demonstrate that even a large leak of refrigerant in the freezer will not cause a fire. Energy testing has also proven that freezers with natural refrigerants consume significantly less energy.
If you are not sure what kind of refrigerant your freezer uses, try checking the nameplate - it should be clearly labeled on there. And if you find that it's time to upgrade to a freezer with natural refrigerants, make sure you use an EPA-certified refrigerant reclaimer when disposing of the old unit.