Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion

Freezing Points:

R11 - 168 F.
R12 - 252 F.
R22 - 256 F.

R22 which can change its medium at very rapid way. So which is used in as comfortable way?

Correct. R22's freezing point is -160C.

Correct answer is ammonia.

Correct. The R22's freezing point is -160C.

R22 freezing point temperature is -160 Celsius, i.e. -256 F.

The correct answer is: Ammonia.

Ammonia (R-717) has a freezing point of -77.7°C (-107.9°F), which is the lowest among the options.

Here are the freezing points of the other options:

- R-11 (Trichlorofluoromethane): -111°C (-168°F), but it's already phased out due to its high ozone depletion potential.
- R-12 (Dichlorodifluoromethane): -157.6°C (-251.7°F), but it's also phased out due to its high ozone depletion potential.
- R-22 (Chlorodifluoromethane): -160.5°C (-256.9°F).

Ammonia is widely used as a refrigerant in industrial applications due to its excellent thermodynamic properties, low cost, and low environmental impact. However, it's toxic and flammable, requiring special handling and safety precautions.