Will a portable generator run a portable aircon?
Submitted: Friday, Nov 26, 2010 at 18:37
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wallabyshane
Hi all,
Can anyone tell me if a portable gen. will run a portable air con unit please. If so, how many HP will the gen. need to be?
Thanks.
Wallaby.
Reply By: OzTroopie - Saturday, Nov 27, 2010 at 00:55
Saturday, Nov 27, 2010 at 00:55
Hi Wallaby,
I've always had a good run with Honda generators. They have a good reputation, along with a nationwide service and spare parts network. You may struggle to get spares if you buy a cheap Unit. For this reason i'd recommend a Honda or Yamaha generator. Just for the record i'm not involved in the generator sales industry.
Anything over 2-3 KVa starts getting heavy and is usually on a trolley or wheels. Have a look at the Honda EU30i and EM50is. Just remember when adding up your watts, the 4.5KVa may not cover the start up draw on your aircon. For example, it could spike to 5.5KVa when the motor turns over on startup - someone with more electrical knowledge may be able to explain this better.
Not sure if there's a specialised caravan aircon with lower power draw out there. The smaller the generator you require, the less fuel you'll use and the quieter it'll be.
Safe Travels,
OzTroopie
AnswerID:
437044
Follow Up By: wallabyshane - Saturday, Nov 27, 2010 at 11:35
Saturday, Nov 27, 2010 at 11:35
Hi OT,
Thank you.
Will have a look at both. I'm guessing the bigger/more powerful the gen set is the more chance of it working?
Will ask my local sparky.
Appreciate the input.
Regards,
WS
FollowupID:
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Reply By: Member - John and Val - Saturday, Nov 27, 2010 at 14:27
Saturday, Nov 27, 2010 at 14:27
Wallaby -
First point - evaporative cooling v's a compressor driven portable air conditioner.
The evaporative cooler is far simpler, but in fact, although the air coming out has a lower temperature, it actually contains more heat than the incoming air. This heat is carried in the higher humidity resulting from evaporation of water, plus of course the energy used to move that air. A downside of simple evaporative systems is the increased humidity, which reduces the effectiveness of our own evaporative cooling system, sweating. The wet towel and fan system is the same. They do not remove heat from the "cooled" area.
Compressor systems are simply heat pumps, pumping heat from inside the cooled space to outside. Consequently they have an "inside" part, (the evaporator) and an outside part ( condenser). In a portable system these are close coupled together resulting a pretty ineffective system. While split systems used in homes typically pump 2.5 to 3.5 times as much heat energy as the energy required to drive them, portable systems are usually 1.5 to 2 times.
I think by a 4.5 kW unit you are referring to the cooling capacity, not the power required to run it. IF I'm right in this, you'll probably need at least a 2kva alternator to start the air con motor. Should run off something smaller, but they are pretty demanding on starting. So.. to cool the sleeping area at night you'll need a substantial generator and it'll need to be quiet so you can sleep AND for the sake of your neighbours too.
Cooling the annexe area has too many variables to even try a guess. Sunlight on the roof and walls has an energy of up to about 1 kW per square metre and a fair bit of this will end up in the annexe. I wouldn't even attempt to cool it.
In our experience, a fan to provide air movement so as to make good use of your own personal sweat based evaporative cooling works pretty
well.
Cheers
John | J and V
"Not everything that can be counted counts, and not everything that counts can be counted."
- Albert Einstein
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Follow Up By: wallabyshane - Saturday, Nov 27, 2010 at 17:03
Saturday, Nov 27, 2010 at 17:03
Thanks
John.
So all in all I shouldn't worry about it.
Appreciate your thoughts.
WS
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708502
Reply By: Member - edwin (QLD) - Saturday, Nov 27, 2010 at 16:14
Saturday, Nov 27, 2010 at 16:14
by the time you buy a 4.7kw a/c unit and at least a 6 .5kw genset to run the thing ,unless its an inverter type (doubt it) plus a few jerry cans of fuel, youll need another trailer to put them in ,best bet is to get a couple of HI VELOCITY 240 volt or smaller 12 volt fans,the 450 mm fans are quite reasonable in price(supercheap auto ABOUT $70),theyll blow a hair piece off an old man at 10 metres,it will save you thousands that you can then spend on beer and wine to help you get to sleep on those hot nights
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Follow Up By: wallabyshane - Saturday, Nov 27, 2010 at 17:04
Saturday, Nov 27, 2010 at 17:04
LMAO.
Beer and wine it is Edwin!
Thanks.
WS
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