Solar Powered Air Con- possible?

[FloridaSun]

Luckily the fridge works fine and we have plenty of cold beer..!!

The house is all wood (see pic below) so normally AC is not required. It's just those 2-3 months of still, humid nights that are bad. We are way off the beaten track and our electricity supply is at the end of the line, so we often get power drops. I was looking into Solar power alternatives, but unfortunately unlike elsewhere in the world, the Thai Government doesn't give any incentives to install it.

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Nice house! Off the beaten track? You're up around Chiang Rai somewhere?
I remember even in the cities power could be unpredictable, go out a few times a week, but usually not for long. ha! Thai guvment doesn't even give incentive for electricians to do proper (safe) wiring. You would probably be better off with a small genset for the A/C and a few lights on those hot stuffy nights.

[hadders]

We're about 2.5 hours drive NE of Bangkok, on the border of the Khao Yai National park. Pretty high elevation, so we tend to cooler weather than the rest of the area.
Having looked at the costs of Solar power, I am reluctantly going to have to go for a small genset. Still have a small Solar set up for my Hydroponics though, so not giving up altogether.

[FloridaSun]

We're about 2.5 hours drive NE of Bangkok, on the border of the Khao Yai National park. Pretty high elevation, so we tend to cooler weather than the rest of the area.
Having looked at the costs of Solar power, I am reluctantly going to have to go for a small genset. Still have a small Solar set up for my Hydroponics though, so not giving up altogether.

Generators. Noisy but necessary unless willing to spend a huge amount on batteries.

yuck, Bangkok, about the only place in Thailand I don't like. Too much people and pollution like most big cities.
Thailand is a beautiful country.

[SunEagle]

Generators. Noisy but necessary unless willing to spend a huge amount on batteries.

yuck, Bangkok, about the only place in Thailand I don't like. Too much people and pollution like most big cities.
Thailand is a beautiful country.

You would be surprised how easy it is to sound proof a generator. When I went to the NASCAR race in Atlanta a couple of years ago everyone had generators in the RV camping area. But due to the noise limitations (didn't want to wake the kids after 10 pm) you either had to shut down your gen set or make it real quite. I saw a lot of homemade boxes with baffles and exhausts vents to allow the gen set to run yet stay very quite.

[FloridaSun]

You would be surprised how easy it is to sound proof a generator. When I went to the NASCAR race in Atlanta a couple of years ago everyone had generators in the RV camping area. But due to the noise limitations (didn't want to wake the kids after 10 pm) you either had to shut down your gen set or make it real quite. I saw a lot of homemade boxes with baffles and exhausts vents to allow the gen set to run yet stay very quite.

yes, they do need a bit of work to quiet them down. Personally I'd rather hear the thump thump of a Listeroid than a quiet modern high rev engine. Listeroids aren't so portable tho

[SunEagle]

yes, they do need a bit of work to quiet them down. Personally I'd rather hear the thump thump of a Listeroid than a quiet modern high rev engine. Listeroids aren't so portable tho

I haven't seen a Listeroid Diesel generator in a real long time. They do have a distinctive sound which is less annoying than a new gas generator.

Of course you can go use one of them Honda's which have a dB rating in the mid 50's which is pretty quite.

[geebus]

If you have some grid power, could you not use this to charge a battery bank when available?

Would save on some of the cost of solar panels and controller, at least.

[Sunking]

If you have some grid power, could you not use this to charge a battery bank when available?

Would save on some of the cost of solar panels and controller, at least.

That is what smart money would do. Green Wash money no way Jose.

[ChrisOlson]

Could this unit work? and if so how many panels/batteries would I need to power the unit overnight (say 10 hours).
I would think it would need quite a large syatem.

Kind of an old thread. But we installed central A/C for our home this year for the 4 weeks or so in summer when it gets humid and stays over 90F. The solar runs it fine when the sun is up. At night there's no way you can run A/C off battery power very economically. We use diesel power to run A/C at night. We have just a small 1.5 ton Trane unit.

Someone mentioned using a Lister or Listeroid clone. Don't even think about it for AC compressors. A Lister makes a big bang, then sits there and huffs and puffs and sucks and blows for two crankshaft revolutions before it hits the crank pin with another big bang. The torsional vibration on the crank is severe, despite the flywheels. 3,600 rpm engines don't have that problem.

Never seen a gen head yet that can put out power cleaner than about 15-20% THD with a Lister 6/1 as the prime mover. A/C compressors do not like power that "dirty" and it will run hot and lose a lot of electrical efficiency because of it - and that's assuming a Lister 6/1 can even deliver the surge power to start an A/C compressor, which they can't. A/C compressors typically draw 2.5-3x their running amps for starting and 5x running amps at locked rotor.

If you are off-grid and need to run A/C then buy a good diesel generator. If you have grid power don't even think about trying to run A/C with solar power
--
Chris

[Sunking]

Never seen a gen head yet that can put out power cleaner than about 15-20% THD

That is no where close to an accurate statement. While that may be true from a generator you buy at Northern Frieght, but even low end Honda, Briggs and Stratton, Generac are 2% or less. Move up a little and you get 0% THD.

[ChrisOlson]

That is no where close to an accurate statement. While that may be true from a generator you buy at Northern Frieght, but even low end Honda, Briggs and Stratton, Generac are 2% or less. Move up a little and you get 0% THD.

Not when being driven by a 6/1 Lister. The flywheels speed up and slow down with every power stroke due to severe torsional vibration in the crank. The uneven power delivery to the gen head causes really bad THD. Most Listers use belt driven gen heads because they run at 900 rpm and either a 4 pole or 2 pole generator will be used at the correct drive ratio. Ever seen the belt on a Lister driving a gen head? The belt amplifies the problem.

You have to run a gen head at constant speed with smooth input to get good clean power out of it. I've seen some Lister setups that are so bad that the inverter won't qualify it because it can't track it to sync with it.
--
Chris

[inetdog]

That is no where close to an accurate statement. While that may be true from a generator you buy at Northern Frieght, but even low end Honda, Briggs and Stratton, Generac are 2% or less. Move up a little and you get 0% THD.

You conveniently chose to leave "with a Lister 6/1 as the prime mover." out of your quote.
The straw man you conducted by doing that was easy to knock down.
But when dealing with a generator head, not allowing the option of an inverter generator, I think that 0% (even generously interpreted as less than .5%) would not be very easy to reach.

PS: Among portable generators (admittedly not going to produce the best possible power quality) Low THD is generally considered to be below 5%.

A random sample of three Cummins prime mover stationary diesel generators in the over 10kW range found the best one offering < 1.8 % THD with NO LOAD and up to 5% THD at full balanced linear (non motor) load.

PPS: One of the specifications even introduced the truly amazing concept of Total Harmonic Distortion at a single frequency, which got below 3% even when the Total Harmonic Distortion for all harmonics was greater than 5%.

[ChrisOlson]

But when dealing with a generator head, not allowing the option of an inverter generator, I think that 0% (even generously interpreted as less than .5%) would not be very easy to reach.

It's actually almost impossible to achieve less than 5% with conventional wound field generators. I mostly worked on megawatt-class diesels at Cummins and I've never seen even one of those that was much better than 5%. Typical portable generator range for cheap box store generators will be 10-15%. The ones with electronic throttle regulation and CT sensing on the output will achieve 5%, but they are pretty expensive sets.

Inverters are usually 2% or less.

With a Lister 6/1 driving a gen head with a belt you're lucky to keep the freq +/-2Hz from nominal with no load on it. Put a load on it and it gets worse as the crank "snaps" back into shape after every power stroke, transmitting the torsional vibration to the flywheels and belt drive.
--
Chris

[Sunking]

A random sample of three Cummins prime mover stationary diesel generators in the over 10kW range found the best one offering < 1.8 % THD with NO LOAD and up to 5% THD at full balanced linear (non motor) load.

Yeah but so what? The generator is not causing the distortion which is meaningless, it is the load equipment causing it. Care to guess what the utility supplies?

[Sunking]

You conveniently chose to leave "with a Lister 6/1 as the prime mover." out of your quote.

Not intentionally it was painting all generators with a broad stroke which has now been done by the OP. In off grid application THD is pretty much meaningless because the generator feeds a battery charger which in most designs is very tolerant of THD. None of that gets past the batteries. Fact is most medium quality generators and up are in the 5% range which is better than the utility can give you. That makes it a moot point.