Rating of Refrigeration Machine

Rating of Refrigeration Machine

The practical of refrigeration is expressed in terms of ‘tonne of refrigeration’ (briefly written as TR). A tonne of refrigeration is defined as the amount of refrigeration effect produced by the uniform melting of one tonne (l000 kg) of ice from and, at 0°C in 24 hours.

Since the latent heat of ice is 335 kJ/kg, therefore one tonne of refrigeration,

1 TR = 1000 x 335 kJ in 24 hour

= (1000 x 335) / (24 x 60)

= 232.6 kJ/ min

In actual practice, one tonne of refrigeration is taken as equivalent to 210 kJ/ min or 3.5 kW (i.e. 3.5 kJ/ s)

One tonne (1000 kg) of ice requires 335 kJ/ kg to melt. When this is accomplished in 24 hours, it is known as a heat transfer rate of 1 tonne of refrigeration (1TR).