What is Unit of refrigeration or Rating for Refrigeration - Derivation

Unit of refrigeration

Rating for Refrigeration indicates the rate of removal heat. The unit of refrigeration is expressed in terms of ton of refrigeration (TR). One ton of refrigeration is defined as the amount of refrigeration effect (heat transfer rate) produced during uniform melting of one ton (1000kg) of ice at 0°C to the water at the 0°C in 24 hours.
 

 

 

Calculation for one ton of refrigeration

Latent heat of ice is 335KJ/kg (heat absorbed during melting of one kg ice)
1 Ton of refrigeration,  1TR= 1000*335 in 24 hours
=(1000×335)/(24×60) in one minute
= 232.6 kJ/min

Theoretically one Ton of refrigeration taken as 232.6kJ/min, However in actual practice, it is taken as 210kJ/min.
1 ton of refrigeration approximately equal to 3.5kW or 12,000 BTU/h