a/c calulations

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rfr32

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Does anybody have a formula for a/c units when
all you know is the tons of the unit and the voltage. if so let me know.

thanks.
 
Re: a/c calulations

For older AC units, the conversion is roughly one ton of AC per hp of the compressor. Newer units might provide 1.5 tons per hp.

1 hp is equivalent to 746 Watts, but considering inefficiency of the compressor, I would say 1 KW is required to drive a 1 hp compressor. On my very old 3-ton unit, the current draw is about 19A at 240V, single phase. Assuming a 75% PF this is about right considering that the condenser fan and crankcase heater currents are included.

A ton equates to 12,000 BTU/hr, but does anyone know the origin of the "ton"? I do.
 
Re: a/c calulations

Edit Edit Edit Edit : I took my answer out because I'm pretty sure it's right and nobody else spilled yet. : Edit Edit Edit

What is the quantity of heat energy removed by the evaporation of 1 water molecule?

[ January 23, 2005, 03:58 AM: Message edited by: physis ]
 
Re: a/c calulations

Sam, that is the heat of evaporation. Now what is the heat of fusion of one molecule. For that matter, how many molecules in a ton of water?
 
Re: a/c calulations

I don't know those Rattus, could probably find 'em though.

But I didn't see a value in your answer. :D
 
Re: a/c calulations

Sam, if you have just one molecule it is already in vapor form! That is, it is already evaporated.
 
Re: a/c calulations

Alright, well I remember it at 52 calories.

Edit: Doesn't the energy in "atomic" fussion depend on the atom being created or the two atoms to start with?

[ January 23, 2005, 03:59 PM: Message edited by: physis ]
 
Re: a/c calulations

Is it the how much cooling is done by the melting of a ton of ice in one day?
 
Re: a/c calulations

Originally posted by physis:
Is it the how much cooling is done by the melting of a ton of ice in one day?
Click to expand...
Yes :cool:

Tonnage The unit of measure used in air conditioning to describe the cooling capacity of a system. One ton of cooling is based on the amount of heat needed to melt one ton (2000 lbs.) of ice in a 24 hour period. One ton of cooling is equal to 12,000 Btu/hr.
Click to expand...
Liebert Air Conditioning Glossary
 
Re: a/c calulations

Handy link, I saved it.

I found this on the web:

How many thermal Kw is a ton?

No fair checking that site, it looks like it would be in there.

Edit: it's not in there.

[ January 24, 2005, 04:18 PM: Message edited by: physis ]
 
Re: a/c calulations

when ice melts, it absorbs 144 btu of heat/pound, this is a basic physical constant. so when a ton of ice melts, it absorbs 2000 lbs * 144 btu/lb = 288,000 btu. if this is averaged over a 24 hour day, it amounts to 12,000 btu per hour.

tons of a/c actually did at one time refer to tons of ice. when mechanical refrigeration came into common place, there was an attempt to try to size them according to what people were used to. in a very rough sense, a 5 ton a/c unit was equivilant in cooling capacity to 5 tons of ice melting per day.
 
Re: a/c calulations

I got it at 3.516

Did you know that one or look it up?

I didn't know it.
 
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