The choice of a refrigerant depends upon: 1. Refrigerating capacity 2. Type of compressor used (reciprocating, centrifugal or screw) 3. Service required (whether for air conditioning, cold storage or food freezing) Which of the above statements is/are correct?

1 and 3 only
1 only
3 only
1, 2 and 3

LohaHridoy

4 views

2025-01-04 04:42

1 Answers

AhmedNazir

Option 1 : 1 and 3 only

The choice of a refrigerant mainly depends upon the refiregeration capacity required. The refrigerant should possess good chemical, thermal and physical properties. Based on the properties of the refrigerant the suitability of the refrigerant is judged.

Refrigeration capacity is the ability of the refrigerant to take heat away from the evaporator. If a refrigerant has more latent heat of vaporisation then it will carry away more heat away with it for a given mass flow rate. In the following table common refrigernats and their latent heat of vaporisation is given

Refrigerant	Enthalpy of Vpourisation (kJ/kg)
R 11	182.5
R12	165.8
R 134a	217
R 22	233.7
NH₃	1368.9
H₂O	2257.9

The refrigerant is also selected on the basis of the application

Refrigerant	Enthalpy of Vpourisation (kJ/kg)
R 11	Used in the large capacity central air conditioning plant
R12	Used in the small units like domestic refrigerator, water coolers
R 22	Used in the window type air conditioners
NH₃	Used in the clod storage plants
CO₂	Used in direct contact freezing of the foods
Brine	Used in milk chilling plants
Air	Used in gas liquification

There is the suitability of different refigernat with th different compressors centrifugal or reciprocating but the choice of refrigerant will be independent with the compressors, as every refrigerant has some compatibility with some compressors therefore the choice of refrigerant will not be based on that.

4 views Answered 2022-09-04 04:29

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