Why cooling capacity unit of domestic refrigerator and Air Conditioner (AC) is different? – Mechanical Engineering

# Why cooling capacity unit of domestic refrigerator and Air Conditioner (AC) is different?

Have you ever wondered ? Why capacity of domestic refrigerator and Air Conditioner (AC) is different though both are refrigeration system? What is the basic difference between them with respect to the cooling capacity?

The capacity of domestic refrigerator is normally rated in ‘Litre’. Litre actually a unit of volume and it is also applicable to the domestic refrigerator while dealing with space to be cooled. Thus, litre capacity actually indicates the volume or space to be cooled by domestic refrigerator.

On the other hand, capacity of Air Conditioner (AC) is given by term ‘Ton’. Now, this term,

What is one Ton refrigeration?

‘Ton’ is actually a name given to amount of heat to be extracted from 1 short ton (907.18474 kg) of water at 0 degree C to convert it to ice at the same temperature in 24 hours. (Note: 1 large ton = 1016.0469 kg, 1 metric ton = Tonne = 1000 kg)

In other words, refrigeration rate required to freeze 1 ton of water to ice in 24 hours at 0 degree C.

Thus, 1 Ton of refrigeration = 1 TR = (latent heat of ice)x(amount of water)/time

= 334 x 907.18474 /(24 x 3600)

= 3.50 kW

So, both refrigeration system has different capacity term namely ‘Litre’ (Space to be cooled) & ‘Ton’ (3.5 kW) energy to be removed for cooling)