Unit of Refrigeration

Tonne of Refrigeration (TR) 

The amount of heat removed (i.e., refrigeration effect) from 1 tonne* of water from 0 °C to make 1 tonne of ice at 0 °C in 24 hours.

It can also be explained as the amount of heat extracted to make 1 tonne of ice from and at 0 °C in 24 hrs.

To make ice from water at 0 °C, it is important to remove latent heat**.

For water, latent heat = 335 kJ/kg.

    Therefore, one tonne of refrigeration = 1000 X 335 kJ in 24 hrs.

   =  (1000 X 335 )/24 kJ/hr

     

   = 13,958.3 kJ/hr

   =  (1000 X 335 )/(24 X 60) kJ/min

   = 232.6 kJ/min

In practice, 1 tonne of refrigeration is equivalent to 210 kJ/min or 3.5 kJ/Sec of heat.

Note:

*1 tonne is equivalent to weight of 1000 kg.

**Amount of heat transfer required to cause a change of phase in mass of a substance at constant temperature and pressure.