The desirable properties of a refrigerant are as follows:
- High critical temperature to have large isothermal energy transfer.
- The specific heat of liquid should be as small as possible and of vapour should be as high as possible to give less superheating of vapour.
- High latent heat of vaporization to get more refrigeration effect.
- Large conductivity to reduce size of condenser and evaporator.
- Low specific volume of vapour
- Low freezing point such that there is no blockage during flow through evaporator.
- Non corrosive to metal and inert so as to not react with other materials and commodities of the refrigeration system.
- Non-toxic
- Low boiling point
- Non-flammable and non-explosive
- Low cost and easily available
- Easy to liquefy at moderate pressure and temperature
- Easy of locating leaks by odour or suitable indicator
- Mixes well with oil.
- Low viscosity so that pressure drop is small.