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Home > Archive > Alternative Power sources > July 2005 > how much power does this take?
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how much power does this take?
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| Approx how much power, in kw, does a 4 ton air con unit draw? Don't need a
precise number. Ballpark will do nicely.
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"RB" <rbig@bellsouth.nospam.net> wrote in message
news:9rVze.52207$Tt.29217@bignews3.bellsouth.net...
quote:
> Approx how much power, in kw, does a 4 ton air con unit draw? Don't need
a
quote:
> precise number. Ballpark will do nicely.
running or starting?
starting current can be 6 times running current.
The other posters math is right on
except there are ancillary fans that need to be entered into the equation.
Since you do not state the age of the unit. I could be anywhere from 24 amps
to more than 30 once it is up and running.
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| the seventh sign 2005-07-09, 11:25 pm |
| Steve Spence wrote:[vbcol=seagreen]
> One ton equals 12000 BTUs per hour.
>
> 1 kW = 3412.2 Btu/h
>
>
> Steve Spence
> Dir., Green Trust, http://www.green-trust.org
> Contributing Editor, http://www.off-grid.net
> http://www.rebelwolf.com/essn.html
>
> RB wrote:
>
3412.2Btu/hr 1kw
1 ton 12000 Btu/hr 3.516792685kw
4 ton 48000 Btu/hr 14.06717074kw
Check the math please.
Thanks
TSS
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| Anthony Matonak 2005-07-09, 11:25 pm |
| I'm told air conditioners move more energy than they consume.
The ratio varies depending on the hot/cold temperature difference
and the model of the air conditioner but I've heard 3/1 bandied
about quite a bit. This would mean that it takes 1/3 the energy
that it moves.
So 4 ton = 4x12000/3412.2/3 = 4.7 kW.
Most air conditioners don't run continuously, of course, but
around here (Los Angeles) it's not uncommon for the central
air in a house to consume anywhere up to 50 kWh/day with
24 kWh/day being around the average.
Anthony
Steve Spence wrote:[vbcol=seagreen]
> One ton equals 12000 BTUs per hour.
> 1 kW = 3412.2 Btu/h
>
> RB wrote:
>
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| Steve Spence 2005-07-09, 11:25 pm |
| Energy Efficiency Ratio; is figured by dividing BTU hours by watts.
My 6200 BTU unit, with a EER of 9.7, consumes 590 watts during operation.
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html
Anthony Matonak wrote:[vbcol=seagreen]
> I'm told air conditioners move more energy than they consume.
> The ratio varies depending on the hot/cold temperature difference
> and the model of the air conditioner but I've heard 3/1 bandied
> about quite a bit. This would mean that it takes 1/3 the energy
> that it moves.
>
> So 4 ton = 4x12000/3412.2/3 = 4.7 kW.
>
> Most air conditioners don't run continuously, of course, but
> around here (Los Angeles) it's not uncommon for the central
> air in a house to consume anywhere up to 50 kWh/day with
> 24 kWh/day being around the average.
>
> Anthony
>
> Steve Spence wrote:
>
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| nicksanspam@ece.villanova.edu 2005-07-09, 11:25 pm |
| Steve Spence <sspence@green-trust.org> wrote:
quote:
>Energy Efficiency Ratio; is figured by dividing BTU hours by watts.
Divide Btu PER HOUR by watts.
quote:
>My 6200 BTU unit, with a EER of 9.7, consumes 590 watts during operation.
That's a 6200 Btu/h unit. Let's not confuse power and energy.
Nick
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| In article <11d0f8jqv10um67@corp.supernews.com>,
the seventh sign <die.now.spammers@internet.now> wrote:
quote:
> 3412.2Btu/hr 1kw
> 1 ton 12000 Btu/hr 3.516792685kw
> 4 ton 48000 Btu/hr 14.06717074kw
>
> Check the math please.
> Thanks
>
> TSS
Well the math is ok but the premis is suspect. The OP wants to know
how much electricity is is going to take to run his AC unit. Not how
much energy is required to be moved to cool his house. There is a big
difference in how much energy he has to move to cool his house and how
much energy it takes to move the BTU's from inside the house to outside
the house. You calculated how many BTU's he has to move and then
converted that to KW's, but that isn't what he asked for. He wants to
know how much it is going to cost him in USDOLLARS to keep his house
cool, each and every day, and that calculation is going to require a lot
more information than you started with........ but nice try anyway....
Me
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| Thanks for the responses. Good info.
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| Tim Keating 2005-07-10, 12:25 pm |
| On Sat, 9 Jul 2005 14:02:02 -0500, "RB" <rbig@bellsouth.nospam.net>
wrote:
quote:
>Approx how much power, in kw, does a 4 ton air con unit draw? Don't need a
>precise number. Ballpark will do nicely.
One ton == 12,000 BTU/hr.
SEER == BTU/hr /Watts.
or
BTU/hr / SEER = Watts.
Four ton(48000) / 10 SEER == 4800 watts or 4.8 kW
Four ton(48000) / 14 SEER == 3428 watts or 3.4 kW
Actual power draw will vary depending on environmental conditions.
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| nicksanspam@ece.villanova.edu 2005-07-10, 12:25 pm |
| Me <Me@shadow.orgs> wrote:
quote:
> the seventh sign <die.now.spammers@internet.now> wrote:
>
[vbcol=seagreen]
>...You calculated how many BTU's he has to move and then
>converted that to KW's...
No. He calculated how many Btu PER HOUR he has to move and
converted that to kW. Let's not confuse power and energy.
Nick
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| daestrom 2005-07-10, 6:25 pm |
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<nicksanspam@ece.villanova.edu> wrote in message
news:dar1sv$fa1@acadia.ece.villanova.edu...
quote:
> Me <Me@shadow.orgs> wrote:
>
>
>
> No. He calculated how many Btu PER HOUR he has to move and
> converted that to kW. Let's not confuse power and energy.
>
But the OP question was, "How much power, in KW, does a 4 ton A/C draw?"
None of the posters in this branch have considered the COP of the unit, and
that is the direction 'Me' was starting to go.
A 4 ton unit is capable of 48,000 BTU/hr. When it runs, if it has a SEER of
about 10, then it probably draws about 48,000 / 10 = 4,800 watts. If it
runs *continuously*, then it would use 4.8kW * 24h = 115.2 kWh of energy
each day.
But it probably won't run *continuously* (if it does, it's pretty
undersized), so the energy usage will be less.
daestrom
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| Paul Crumpler 2005-07-12, 12:25 pm |
| Depends greatly on the type of AC, but a 4 ton ac will require between 6 and
8 kW.
"RB" <rbig@bellsouth.nospam.net> wrote in message
news:9rVze.52207$Tt.29217@bignews3.bellsouth.net...
quote:
> Approx how much power, in kw, does a 4 ton air con unit draw? Don't need
> a
> precise number. Ballpark will do nicely.
>
>
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| Jim Baber 2005-07-12, 11:25 pm |
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Jim Baber has a question for Paul:
You seem to have some info I am interested in. Would you be willing to
tell where you got the 4 to 8 kW number, it seems very vague.
I am looking for a table that would show that info related to Mfg,
tonnage and SEER # for central to lookup my A/C kW
Paul Crumpler wrote:
[vbcol=seagreen]
>Depends greatly on the type of AC, but a 4 ton ac will require between 6 and
>8 kW.
>
>"RB" <rbig@bellsouth.nospam.net> wrote in message
>news:9rVze.52207$Tt.29217@bignews3.bellsouth.net...
>
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