Question

What are the desirable properties of a good refrigerant ?

Answer 1

Good refrigerant can be identified based on its Thermodynamic,  Chemical  and physical properties. 

These properties can be divided into favourable properties as follows :

A) Thermodynamic properties

1) The critical temperature of the refrigerant should be as high as possible.

2) The critical pressure should be moderate and positive.

3) The specific heat of the liquid should be as small as possible.

4) Enthalpy of Vaporization should be as large as possible to minimize the area under superheat.

5) The conductivity of the refrigerant should be as high as possible.

6) Higher the magnitude of COP, lower will be the running cost.

7) The density of the refrigerant should be as large as possible.

 

B) Chemical properties

1) It should be chemically stable for the operating ranges of temperature. Also, it should not react with the materials of the refrigeration system or with which it comes into contact.

2) The refrigerant should be inert and not catch fire when subjected to high temperatures.

3) The refrigerant used in air conditioning, food preservation etc. should not be toxic as they will come into contact with human beings.

4) The refrigerant should not react with the lubricating oil , Plastics and rubbers which are used to avoid leakage of refrigerant.

 

C) Physical properties

1) it is desirable that the refrigerant has a pungent smell so that its leakage can be detected immediately.

2) The refrigerant should not be miscible with the oil else the lubricating strength will be reduced.

 

 

 

Good refrigerant can be identified based on its Thermodynamic, Chemical and physical properties.