To combat the summer heat, most of us use air conditioning. In the summer, it makes everyone feel at ease. Do you ever pay attention to the air conditioner’s specifications? Its cooling capacity is indicated in tonnage rather than KW or another unit. Why is it measured in tons?
When I was younger, I used to think that the air conditioner was heavy since it weighed tons. But today I discovered I was mistaken. Tonnage of air conditioning has nothing to do with weight. A ton is the amount of heat removed from a room in one hour. Historically, natural ice was utilized to chill a room. Ton of refrigeration is the cooling we receive in a room with 1 ton of ice in 24 hours.
Air conditioners are then invented, and the cooling capacity of ice is matched with the cooling capacity of air conditioners. It means that the cooling effect of one ton of ice is equivalent to the cooling effect of one ton of air conditioner. So, if we place one ton of ice in one room and one ton of air conditioner in another (both rooms must be the same size), the cooling impact will be the same.
Now we’ll see how much heat is absorbed by the air conditioner in the FPS (British unit) system. In the FPS system, 1 ton equals 2000 lb (lb is the symbol of pound). Ice has a latent heat of 144 BTU/lb (BTU is British thermal unit). This means that when one pound of ice begins to melt, it absorbs 144 BTUs of heat.
So 1 ton of ice or air conditioner absorb 2000×144=2,88,000 BTU of heat in 1 day.
Now we divide the above with 24 to find the absorption of heat in 1 hour. 2,88,000÷24=12,000 BTU/hour. This means that a 1 ton air conditioner or ice absorb 12,000 BTU in 1 hour. Similarly, 4 ton air conditioner absorbs 4×12,000=48,000 BTU heat in 1 hour. Therefore, with increase in ton of air conditioner, more heat absorption takes place and hence it can cool more air.
Different ton of air conditioners are required as the size of a room is not same in all places. So, larger rooms need more ton of air conditioners than smaller room.