Improving Aircon efficiency

Air conditioning, fans, and anything related to keeping it cool, such as insulation. This would include any posts generally discussing how to keep it cool, such as which types of blocks are better insulators.... ideal wall thickness for keeping an A/C house cool, etc.

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Re: Improving Aircon efficiency

Postby Psychic » Sun Mar 16, 2014 12:37 pm

Nice experiment. I was just reading about Energy recovery ventilation (ERV) systems. They use the colder air generated by an air-con and basically re-use it. I think the most effective employ a dessicant wheel to remove the moisture first.
There's lots of little things to experiment with if you have the ability to build them. I read that having a water jacket for your fridge coils will reduce the heat emitted, improve the efficiency and provide some free hot water. It's on my list of things to kill my time with on an old fridge, once I actually have a house.
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Re: Improving Aircon efficiency

Postby schuimpge » Sun Mar 16, 2014 6:54 pm

One of the other things on my list is a peltier to cool down the gas going into the compressor. Solar and a small battery to power it. Would freeze the gas from the head-unit and make work for compressor less.
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Re: Improving Aircon efficiency

Postby BKKBILL » Sun Mar 16, 2014 9:13 pm

When in BKK I had a heat exchanger installed on the hot gas return line just before the compressor. It kept us in hot water. Here is how they work.

http://techcrunch.com/2011/06/12/air-co ... er-heater/

Here in Chiang Mai we are using solar.
Two years now and I have yet to connect the electrical back-up element. We have hot water piped to all sinks and showers, my wife uses a lot of hot water so it is good to know we are using renewable energy.
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Re: Improving Aircon efficiency

Postby schuimpge » Tue Mar 18, 2014 10:34 am

How big is the tank on your heater.
And what type? All in one unit? Or separated tank/panel?

Mine arrived yesterday, will be unpacking it this afternoon.
All in one with 130 liter tank, 1500 watts backup heater with electronic controls.
Bought it from ABO. Must say, the guy there is very responsive and that's what pulled me over.
Only waiting for the thermostatic valve to not get scalding hot water in the shower.

Guess that next year I'll be putting more solar on the roof, waiting for now and see how the rest works out.
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Re: Improving Aircon efficiency

Postby BKKBILL » Tue Mar 18, 2014 2:32 pm

The water tank was a 150L stainless steel insulated tank installed outside next to the compressor with a flat plate heat exchanger doing the work.

You reduce power consumption to the compressor by lowering gas temperature and transferring that heat to your domestic water heater.

Here is what the flat plate looks like
url.jpg
url.jpg (6.15 KiB) Viewed 1465 times


and the connection without all solar on the left of hot water tank.
CCI00001.jpg


Here in Mae Taeng I used ABO with their high pressure solar heat exchanger. Quite happy with it.
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Re: Improving Aircon efficiency

Postby schuimpge » Tue Mar 18, 2014 6:39 pm

Nice setup. I will need to get my aircon guy to solder a copper clamp with a flat surface to the pipe that goes into the compressor. A peltier goes on top sandwiched with a heatsink plus computer fan. Small power-supply connected to the compressor so that it starts and stops with the compressor cycle.
That could be done with solar but then a bit more work with relais and switches.

But the idea is to deep cool the gas going in as the peltier gets below zero in seconds.
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Re: Improving Aircon efficiency

Postby schuimpge » Tue Mar 25, 2014 7:51 pm

Grrrr. Had to start measuring again. Empty batteries on the meter.
But ok, using now 50 baht a night. It's much more hot sure, so I think I reinstall the cooler next Saturday and space the period better/shorter.

Then go hunting for a small solar panel and get an old UPS for power.
2 copper plates, my aircon guy to weld it to the aircon pipe and then freeze my aircon return from the bedroom with a peltier...powered by solar...
That should kill my bill..
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Re: Improving Aircon efficiency

Postby schuimpge » Mon Mar 31, 2014 6:49 am

Well, got 1 week of measuring without water. 306 Baht for 6 days. That's 51 Baht per night.
Then started the cooler up again yesterday, came out this morning at 46 Baht. That's 10% but the spraybar hose came loose so I don't know how many hours it has been like that.

But 10% is a very respectable saving for a 200 Baht investment.
Will set it up more sturdy this evening and check again.
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Re: Improving Aircon efficiency

Postby schuimpge » Mon Mar 31, 2014 7:06 am

Checked on some refrigeration forums to get advise. Learned there that the best way to use peltier cooling would be just after the compressor and before the condenser, where the gas is very hot and needs to cool down to a liquid state again. If you cool that part of the system, you basically enlarge the condenser coil which will reduce the head-pressure that the compressor has to overcome.
There is a one-way valve where the gas is pumped out of the compressor, so the cooler the gas in the condenser coil, the lower the back-pressure at that valve, the lower the power output necessary for the compressor to overcome that. Less power is less energy is less money of course.
I am already helping a bit with the swamp cooler behind the coil.. But found that its quite easy to reach the pipe that gets the peltier clamped on.

Will need to measure the temperature it gets to, then get a couple of small plates and a heat sink with fan to take out the Peltier heat.
The peltier then connected to solar and small battery.
I need to ensure that the hot side of the peltier gets cooled as much as possible because the cold side has a max Delta T of 67'Celcius.
This means that if I manage to keep the hot side below 65'Celcius, then the cold side would reach -2'Celcius.

Matter of big enough heat sink / fan and see if I can get cooler air from the swamp-cooler through the heat sink.

Will be interesting.
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Re: Improving Aircon efficiency

Postby Psychic » Fri Apr 04, 2014 10:58 pm

BKKBILL wrote:
Here in Mae Taeng I used ABO with their high pressure solar heat exchanger. Quite happy with it.



Bill, I contacted ABO about their heaters. I asked them about the hook up, as in would it require a completely separate hot water feed and demand pressure pump. They said it could all be done with one pump for both hot and cold water and to contact a Phuket company for instruction. I did and they never got back to me. So I was interested in your set-up, if you don't mind me asking.
Sorry for diverting the thread.
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Re: Improving Aircon efficiency

Postby BKKBILL » Sat Apr 05, 2014 10:10 am

If it's about solar I'm sure schuimpge won't mind. :lol:

Here is the web site for ABO solar water heaters showing the set-up.

http://www.abotrading.co.th/Product/Sol ... r_Heater/2

The type both schuimpge and I used is the pressurized system

(viewtopic.php?f=3&t=4282 water heater starts about page 5 or 6)

Works the same as a regular storage hot water tank with copper vacuum tubes as the heat source. On my system there are no pumps or moving parts as our village has a good water supply.

You will have to pipe in the hot water supply lines which I did to all my plumbing fixtures with PPR pipe. Your fixture mixing valves will also need a hot and cold water connection.

http://www.pprpipes.com/PPR-Pipes.htm
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Re: Improving Aircon efficiency

Postby schuimpge » Sat Apr 05, 2014 11:32 am

I don't mind at all BKKBILL :mrgreen:
I am using a 12v booster pump driven by battery and solar panel.... But depending on how you want to set it up, it's very easy to just hook it up to your normal house water pump.
If you only want to use it for the shower, then you just run one extra hot water line to the mixing valve and done.
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Re: Improving Aircon efficiency

Postby Roger Ramjet » Sat Apr 05, 2014 1:45 pm

schuimpge wrote:I am using a 12v booster pump driven by battery and solar panel.... But depending on how you want to set it up, it's very easy to just hook it up to your normal house water pump.
If you only want to use it for the shower, then you just run one extra hot water line to the mixing valve and done.

Just how much is all this costing? All these "little extras" like batteries, piping, wiring, etc.
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Re: Improving Aircon efficiency

Postby schuimpge » Sun Apr 06, 2014 11:21 am

Solar Hot Water Collector 35,000
Battery 5,500
Panel 5,000
12v Pump 1,500 (x2)
Solar Charge Controller 1,000

Installation for me is part of the renovation.
Fittings and piping is mostly normal Blue PVC piping except the hot water run from the solar tank.
I added an extra safety valve for 1,200 baht to keep the temperature below 48'C.

My savings will be around 250 Baht p/month for shower heater and about the same for main pump when it's replaced by another 12v pump.

Water pressure in the system is about 40 PSI. Gives a very nice comfortable shower pressure.

Overall, I am looking at an ROI of 7 to 10 years, depending on how much electricity prices will increase.
Expected life for the system is about 20-25 years.
The biggest pleasure and satisfaction for me is that I do a little bit on alternative energy systems, I am teaching my contractor different ways of doing things and I bring my monthly bills down.
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Re: Improving Aircon efficiency

Postby schuimpge » Sun Apr 06, 2014 11:32 am

For the airconditioner, hope to find some time this week to make an excel-sheet with usage per day.
That will make it easier to analyze data.

And get fittings made for the Peltier.
That will be very interesting.
Cheers,
Luc
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