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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Improving Aircon efficiency

Postby schuimpge » Sun Nov 03, 2013 1:15 pm

Did some "Red-Neck" setup to improve my compressor electricity use.
It is a very crude setup currently, but first temperature measurements are promising.

The basic idea is to reuse the cold condens water to help your compressor.
The water has a 25 to 27'C temperature and is normally just dumped.
It is however almost pure H2O and reusing it is easy.
So the idea is to cool the air that is sucked into the compressor with that cold condense water.

What I did:
1: make a small water-holding place behind the compressor, where the condenser is. About 10cm deep and the full length of the condenser. In my case it's 65cm and I had 10cm width to work. So 65x10x10cm is the volume of the water.
2: route the water drain-line from your room-unit in there.
3: get a small aquarium power-head (150 Baht, 5 watt)
4: get a 3/4" PVC pipe and drill 1 line of small holes in it.
5: piece of garden hose and some tape to connect pump and PVC pipe.
6. I used 2 old alu mosquito screens, 60x70cm I think they are.
7. Put filter floss (aquarium shop again, 30 Baht for a large bag.) between the 2 screens and tape the screens together.
8. Put the pipe at the top of the screen with the drill holes against the screen.
9. Put this in the water area, with the PVC pipe at the top, pump under water. Make sure it has a slight angle so that water drips down over the screen.
10. Connect the pump to the incoming electric line for the compressor (open side panel, and it's a matter of loosening the screws of the electric line. Stick the pump cables in, tighten them again and you are done.)

This way, the pump switches on when the compressor starts and switches of when it stops...

Tested just now and it looks to bring the temperature passing the condenser down by 3 to 5 degrees.
I'll be curious as to how much that will save, but lower temperatures means less work for the compressor.

Another benefit...it turns out that there is almost zero water draining off. What I see is that the system is pretty much balanced. Continuous top up from the head unit is enough to keep the system running by itself.

Trying it out for a while to see the effect. Also want to test some different configs and run a 'Kill-a-Watt" meter on the compressor. Later. First run the Red-Neck setup for a while..

Cheers,
Luc
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Re: Improving Aircon efficiency

Postby schuimpge » Sun Nov 03, 2013 5:29 pm

Fiddled around a bit more.
Found that the filter mat is not necessary and took that out.
Temperature readings between the screen and compressor are very constant at 29-30'C both running and off.
At the side, temperature when running 35'C, and when off it comes to about 32.
This is in part because the wind is head on today, so whatever the fan blows out, is then blown back around the compressor.
Eventually, an L-shaped water-area with 2 screens, backside and side would cool the compressor by a nice 5'C.
Makes for quite a bit of savings for the work the fan and compressor have to do.
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Re: Improving Aircon efficiency

Postby schuimpge » Mon Nov 04, 2013 10:49 am

Checked temperature yesterday around 9.30pm.. came to 25'C.
That's lower than the setting of the temperature in the bedroom at 26-27..
Looking promising.
Cheers,
Luc
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Re: Improving Aircon efficiency

Postby pattayapope » Mon Nov 04, 2013 12:39 pm

Luc what about some pictures of the setup :D
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Re: Improving Aircon efficiency

Postby schuimpge » Tue Nov 05, 2013 7:17 am

Ah yes...how could I forget the pictures... :roll: :lol:
It's been working nicely...will get into the final setup soon with proper tank and stuff.
But here's the 'Red-Neck' setup....

PB050025.jpg
temperature this morning between the screen-aircon

PB050026.jpg
top of unit with spraybar and screen

PB050028.jpg
side view

PB050029.jpg
hazy picture of the pump at the bottom between screen/aircon

PB050032.jpg
running the pump


Cheers,
Luc
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Re: Improving Aircon efficiency

Postby pattayapope » Tue Nov 05, 2013 11:53 am

I think you have built a swamp cooler, my biggest concerns would be corrosion in the high humidity you have created by using water to go into the condenser :roll:
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Re: Improving Aircon efficiency

Postby thailazer » Tue Nov 05, 2013 12:20 pm

pattayapope wrote:I think you have built a swamp cooler, my biggest concerns would be corrosion in the high humidity you have created by using water to go into the condenser :roll:

It is cool to see experimentation like this, but I doubt there are any savings after adding the pump, small as it is. Algae will be the first thing to be concerned with but you are right that corrosion will follow.
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Re: Improving Aircon efficiency

Postby schuimpge » Tue Nov 05, 2013 1:15 pm

thailazer wrote:
pattayapope wrote:I think you have built a swamp cooler, my biggest concerns would be corrosion in the high humidity you have created by using water to go into the condenser :roll:

It is cool to see experimentation like this, but I doubt there are any savings after adding the pump, small as it is. Algae will be the first thing to be concerned with but you are right that corrosion will follow.


Thanks for the comments...yes, might call it a swamp cooler indeed.
According to my Aircon Guy, there's aircons on the market nowadays who have it built in.
Corrosion, that's a good one, time will tell, but got some points I considered.

Aircon-Compressors are build for outside. In a climate like in Thailand, humidity is already very high (67% today). Dew-point is typically in the 20-25'C range (today in Bangkok 21.7). My swamp cooler is using the low temperature of condense-water, will it bring up the humidity? Yes I guess so. Will it bring it up substantially? Nah..hard head in believing that. I might even argue that I brought down the relative humidity by cooling the air going into the compressor.
The amount of droplets of water going in is zero, the fan basically sucks air from around the screen and it cools down passing that cold area before going into the compressor housing.

Algae...not a chance...: It's 100% H2O, and on top of that, it's continuously refreshed. There's no food or organic matter in that water.

Small pump: Not the best solution but for now ok. Another solution might be to have a drip tray on the top where water trickles very slowly down (drip tray filled up from the Condense-Line directly). There's some drawbacks on that also, but it's without the pump.

Ideally, the small pump would run of the solar panel and a battery I'm getting up and running. But that would add some other things like a 220/12V relay to switch it on and off with the compressor.

It's a first test. On the electricity savings, I'll need to plug my Meter in to check the running-cost with and without the system. Coming weeks I'll be on to that..

Cheers,
Luc
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Re: Improving Aircon efficiency

Postby schuimpge » Tue Nov 05, 2013 1:25 pm

Because of the pure water, there's no salts or other deposits that could cause corrosion.
Remember that Iron does not rust in H2O.
It rusts because there's dissolved oxygen and deposits like Calcium in the water that corrode the metal.

If I would spray a fine mist of tap water on the condensor..Then I would fully agree, it would corrode very fast.
But I'm not using mist spray, I'm using temperature and a large surface that do not let water through and I'm using pure water.
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Re: Improving Aircon efficiency

Postby thailazer » Tue Nov 05, 2013 4:09 pm

Had a rental house and one AC always had the drain tube plug up with clear algae. It can form in the AC but the warmer outside temperatures are more conducive to its growth so it forms in the drain tubes. Run your system for six months and let us know if you have any forming.
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Re: Improving Aircon efficiency

Postby schuimpge » Tue Nov 05, 2013 5:07 pm

thailazer wrote:Had a rental house and one AC always had the drain tube plug up with clear algae. It can form in the AC but the warmer outside temperatures are more conducive to its growth so it forms in the drain tubes. Run your system for six months and let us know if you have any forming.


Never seen any of my aircons plug with algae. Both at home and my factory.
The only plug I have regular on one aircon in the factory is an ice plug due to bad drainage of the condense-pan inside. We solve that by pumping water downstairs into the drain-pipe for a few seconds.
But will keep an eye on it and duly report.

Truth be told, I do get quarterly maintenance done on the aircons. Cleaning the filters, compressor, filling up gas if necessary, etc. cost me only 300 baht per aircon and the aircon will live a long and happy life with it. But that might be a reason I never seen algae forming.

Cheers,
Luc
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Re: Improving Aircon efficiency

Postby Roger Ramjet » Tue Nov 05, 2013 10:42 pm

Luc,
You might consider your air con is working overtime with the denser air (water in the air). It's why they have condensation towers.
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Re: Improving Aircon efficiency

Postby schuimpge » Tue Nov 05, 2013 10:48 pm

Guess you have to wait for the answer..weekend to install the Kill-A-Watt meter
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Re: Improving Aircon efficiency

Postby schuimpge » Sun Mar 02, 2014 2:15 pm

Well, with lots of other things keeping me busy, and the months December and January being very cold, I 'clocked' the compressor for the month of February with the water-cooling.
Image
This one shows the total running cost for the month.

Image
This screen shows to total run-time. Hours in the top, days at the bottom.
3 days, 21 hours, 57 minutes.

I have now removed the water cooling, plugged in and reset the meter and will wait for the next month.
Just for being complete, the figures did not include the water pump.
But with total running hours, it's easy to calculate. Will give the pump wattage and details later.

Cheers,
Luc
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Improving Aircon efficiency

Postby schuimpge » Tue Mar 04, 2014 5:37 pm

Well, too early to draw conclusions, but today's meter said 30.4 baht... That's for one day as I had to reset the meter yesterday evening as it was not set correctly. If every day the same, then it works out to 850 Baht for 28 days. Will need to see the running hours to check on the actual difference..
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