American Mechanical wrote:

BTU per hour compared to ton per day. It all works out in the end.

(A "ton per day" would be 12,000 Btu per hour _per hour_ :-)

Btus are energy, and tons are power, and failing to
recognize the difference (eg to write and think Btu
PER HOUR) is a source of great confusion to people
who know anything at all about physics :-)

Tons are power?

Right 12K Btu PER HOUR is equivalent to 3.5 kW.

Power being measured in watts, I don't believe this holds water. :-)

Saying "Btu PER HOUR" instead of the "Btu" HVAC jargon would remind us
that a Btu is a quantity of heat energy and a Btu per hour is a measure
of power, ie a rate of energy flow. It would also avoid rational but
confusing questions like "You say this is a 6000 Btu air conditioner.
What do I do when the 6000 Btus run out? Buy another?" :-)

A ton of refrigerating effect is equal to the amount of heat that is added
to one ton of 32 deg F ice in order to convert it to 32 deg F water in a 24
hour time period. The latent heat of fusion for water(ice) is 144 BTU per
pound and there are 2000 pounds in a ton therefore you must add 288,000 BTU
within a 24 hour period to melt the ice. 288,000 BTU divided by 24 hours is
12,000 BTU that must be added per hour in order to melt the ton of ice.

Righto.

So, 12,000 BTUH is considered one ton of refrigerating effect.

Nice that you added an H this time. Writing Btu/H is even clearer, or p,
if you like, as in mph or mpg. Watt-hours (Wh) or kilowatt-hours (kWh)
have meaning as units of energy, but a BTUH is meaningless in the context
of physics.

Nick