What gas can you find in the refriderator
http://www.energyquest.ca.gov/how_it_works/refrigerator.html
To determine which gas can be found in a refrigerator, we need to understand the common types of gases used in refrigeration systems.
The most commonly used gas in household refrigerators is a hydrofluorocarbon (HFC) known as R-134a. This gas is colorless, odorless, non-toxic, and non-flammable. R-134a is widely used because it has good thermodynamic properties and does not contribute significantly to ozone depletion.
If the refrigerator is an older model, it might use chlorofluorocarbon (CFC) or hydrochlorofluorocarbon (HCFC) refrigerants, such as R-12 (CFC) or R-22 (HCFC). These refrigerants have been phased out due to their harmful effects on the ozone layer.
Therefore, in most modern refrigerators, the gas you will find is R-134a. However, it is always recommended to check the manufacturer's specifications to confirm the specific refrigerant used in a particular refrigerator unit.