this post was submitted on 03 Sep 2023
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can someone explain this for the uneducated?
It's another one of those weird non-metric units. In the world of air conditioning (or cooling in general), a "ton" is the amount of cooling you'd get from melting a ton (a short ton - that is 2000 pounds) of ice that's already near its melting point. Air conditioners are usually rated in tons per day, with 1-5 tons about right for a typical apartment or house, depending on things like square footage and climate.
I'm the kind of person to argue the merits of the imperial system, and even I think that's bonkers.
What do you think the metric system is based on? It's the exact same thing.
0c is the temperature of water freezing (at sea level, etc.etc.)
100c is the temperature that water boils.
1 kilocalorie is the energy needed to raise the temperature of 1kg of water one degree.
You have to define energy in some way, and almost all of it is related to how it affects water.
Fingers.
Calories are not metric. And there are even two calories. Not as bad as 10 different inches, but use Joule(metric unit, Newton*meter) instead.
Wut? I though it was unit of power per mass of machine. Why, just why?
(side note, thank you for the explanation)
Ffs USA. YOU'RE ALREADY USING kW, JUST GO FULL METRIC ON POWER. Please I'm begging you.
COP = heat moved / power input
kW_out / kW_in = dimensionless value
An air-conditioner with a COP of 2 moves 2 kW of heat for every 1 kW of electrical power you put in.
This hurts so much to find out because the US is already using BTU/hr 🤢. What do you need yet another unit for power for?
You're using W, BTU/hr and ton/day?
Like. Why are you doing this?
😭 look what they did to my boy (units)
That makes sense actually. Thanks!
He's saying they improved in efficiency
In Air Conditioning a "ton" = 12000BTU of heat removal per hour.
It originates from the amount of heat removal over a period of 24 hours needed to freeze a ton of water at 0C:
https://en.m.wikipedia.org/wiki/Ton_of_refrigeration
A quick idea of what cooling/heating you need is your square footage (assuming 8ft ceilings) x 20.
So 600 sq ft of area would need a 1 ton AC or 12,000BTU. Again complicated by outdoor temperature, insulation of the home, and other factors.
Anyway, what the op was saying, for the same tonnage (cooling capacity) old ACs used a ton of electricity. Newer split units are crazy efficient.
Like in 2000 the new requirement for a home AC was a SEER (cooling vs electric usage) of 10. The higher the rating, the less electricity used for a given cooling capacity.
Nowadays you can get the cheaper split units which have ratings of 19-23 SEER2. So they use half or less than half the electricity for the same cooling. Also they can work as heaters in a pinch.
Edit: Quick googling shows that ACs from the 80s could be as inefficient as 6-7 SEER. So a modern 21 SEER2 unit would use 1/3rd the electricity!
WTF BTU is? Bitcoin fork?
British thermal unit. Been around for a century or more and will be around for another century after Bitcoin is gone. I say this owning Bitcoin.
I really hope for my sanity that the US at least switches fully to kW and kWh. They're already using it!