Formula question

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TheCrow

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Looking to figure out tons to voltage amps. Every conversion table is def. I was wondering the easiest way to figure out
 
I think that you would also need to know the SEER rating of the equipment to come up with a table that was anywhere near accurate.
 
Found this 12000btu equals a ton
12000 x2 tons 24000
.293 time 24000 7032 volt amps divide by 240 equal 29.3 amps .
 
TheCrow said:
Found this 12000btu equals a ton
12000 x2 tons 24000
.293 time 24000 7032 volt amps divide by 240 equal 29.3 amps .
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That implies approx. 15a per ton. My 3.5-ton heat-pump unit is running just fine on a 30a circuit.
 
LarryFine said:
That implies approx. 15a per ton. My 3.5-ton heat-pump unit is running just fine on a 30a circuit.
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Very true.
The formula is based solely on electrical conversions only.
Infinity hit on it earlier.
we need to know the energy efficiency ratios.
 
TheCrow said:
That's why I was looking for a formula
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A formula is easy.
In order for the formula to give you the correct numbers you would have to look at the nameplate for variables like the EER (Energy efficiency rating)and the COP (Coefficient of power) if it’s even on there.
After all that searching for the variables to get the right number, you may as well skip all that and just look at the amps on the data plate.
 
TheCrow said:
Looking to figure out tons to voltage amps. Every conversion table is def. I was wondering the easiest way to figure out
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Ton is a unit of weight. Without context, it doesn't mean anything for electricity.

In the context of refrigeration, "1 ton of refrigeration" means it can freeze 1 ton of water into ice in 24 hours. It was used as a metric to compare refrigeration to 19th century practices of using natural ice for our cooling needs. Temperature change is neglected in the unit definition, as it assumes it starts and remains at 32F. This translates to 1 ton of refrigeration = 3.51 kW of cooling power, that the evaporator has to "suck" out of the refrigerated space.

This doesn't necessarily mean 3.51 kW of power is required to run the compressor and other electrically powered components, because there is a coefficient of performance (COP) that measures the ratio of heat transfer power (Q_in) to operating power (W_in). COP depends on specifics of the equipment and operating conditions, but a typical numbers range from 3 to 4. So Larry's approximation of 1kW per ton is reasonable. There is also the power factor of the motor that will affect how Volts*Amps, or Volts*Amps*sqrt(3) in 3-phase relates to kW.
 
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