- AHow much a substance depletes the ozone layer
- BHow much heat a substance absorbs
- The relative impact of a substance on global warming compared to CO2
- DThe boiling point of a refrigerant
Correct answer
The relative impact of a substance on global warming compared to CO2
Why
GWP measures how much heat a greenhouse gas traps in the atmosphere relative to carbon dioxide (CO2), which has a GWP of 1.
The concept behind this question
Substitute refrigerants have to be evaluated as a system with their lubricant, not swapped in isolation. Mineral oil works with CFCs and HCFCs but does not circulate properly with most HFCs, which is why HFC systems generally use polyolester (POE) oil — and POE is strongly hygroscopic, so it absorbs atmospheric moisture fast when left open. Substitutes must also be approved for the specific end use under EPA's SNAP program, and newer A2L refrigerants are mildly flammable, which changes the handling and equipment rules that apply.
More questions on this topic
- Polyolester (POE) oil is used with which type of refrigerants?
- What type of refrigerant is R-410A?
- At what pressure does R-410A typically operate on the high side compared to R-22?
- What is a 'blend' refrigerant?
- What is 'fractionation' of a refrigerant blend?
- How should zeotropic refrigerant blends be charged?
Exam-style practice question. Not an official EPA exam question.