Air-conditions and Refrigeration are always rated in Tons.Why?

Air conditioners are designed on the basis of quantity of heat removal from room, hall or specific area.
Quantity of heat is termed in Tons means if an air conditioner is able to remove 1000 kilocalories of heat or 4120 kilojoules or 12000 BTU of heat in an hour that AC rated as 1 Ton of AC because 1000 Kilocalories or 4120 kilojoules or 12000 BTU(BTU = British thermal unit. A measurement of heat, specifically, the amount of heat needed to raise the temperature of a pound of water by 1°F) equal to one Ton of heat.
Also, this is the same case for freezer and refrigerator i.e. refrigeration system.

Ton of Refrigeration:

A Ton of refrigeration is a unit of power used to describe the heat extraction capacity of air conditioning and refrigeration equipments.
It is defined as the heat of fusion absorbed by melting 1 short ton of pure ice at 0 °C (32 °F) in 24 hours.

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