Air refrigeration system operates on

Explanation:

Air refrigeration:

• Air refrigeration systems belong to the class of gas cycle refrigeration systems, in which a gas is used as the working fluid.
• The air refrigeration system works on the Joule cycle or reverse Brayton cycle or Bell-Coleman Cycle.

The air cycle is favourable for aircraft refrigeration system because:

• The gas does not undergo any phase change during the cycle, consequently, all the internal heat transfer processes are sensible heat transfer processes.
• Air is non-flammable, so there is no risk of fire as in the machine using NH3 as a refrigerant.
• Cheaper as easily available.
• The power per tonne of refrigeration is higher than the VCRS system.
• The weight per tonne of refrigeration is low due to the low density of air and space and volume required is less.
• A small amount of leakage is tolerable with air as the refrigerant.
• Cabin pressurization and air-conditioning can be combined into one operation.