Tried that.... for some reasons the units would ice up. An A/C guy told me that would be a common problem, forgot what the reason was. But, if they don't ice up, a useful application of an otherwise old beatup A/C unit. Also, if you turn them around in the window during the winter, you have a heat pump.... :)
During the summer months, I use a geothermal heat pump to cool the house = while simultaniously eating a 45,000 gallon pool; in the fall, I use it = to heat the house with up until the point where the pool is colder than = our well water at which point I start heating with well water, using = surface disposal instead.
Transition Zone fired this volley in news:e1be0a6b- snipped-for-privacy@n5g2000vbk.googlegroups.com:
Yeah. The whole unit is inside the room. Both the evaporator and condensor are operating on the local air. So long as you isolate the two enough (with a plywood baffle to direct the hot exhaust away from the unit) so that they don't instantly swap air, it works a treat.
No... the evap doesn't freeze. If anything, it sometimes doesn't get cool enough -- as the humidity drops, the temp on the evap has to get lower and lower to condense, and the unit is heating the air at the same time it's cooling it .
LLoyd
Adding a water-cooled condenser to an A/C system shouldn't be that big a deal. The problem is corrosion. I'd expect pool water running through condenser to shorten its life considerably. But, on the other hand, it might save enough energy to pay for a replacement condenser coil every few years. it would make a mess of the pool when it blew oil into the pool water, though.
Jon
The typical water-cooled condenser has the refrigerant tube threaded inside the coiled water pipe, so it is surrounded by flowing water.
The only problem is the typical window AC has the condensate rigged to flow back to the condenser fan and get slung around, to extract an evaporative cooling effect from the water. It probably wouldn't be real hard to defeat that, however. But, it would take a little hacking.
Jon
COOL! (pun intended) I'd like to hear more details about this system.
Jon
Jon Elson fired this volley in news:VvqdnRaW8p7uMVrNnZ2dnUVZ snipped-for-privacy@giganews.com:
It's not hard, and takes no hacking. Just tilt the unit a couple of degrees forward - instead of back - and provide a drain.
Lloyd
No good deed goes unpunished. :(
Replace it with a coaxial coil, ( tube in tube, counterflow ) or add one = at the point just prior to where refrigerant enters the condensor coil = and adjust charge volume accordingly.
BTW: You have mail.
news:e1be0a6b-
Lower the evaporator temp to the dewpoint by partially restricting mass = airflow volume across the coil.
"PrecisionmachinisT" fired this volley in news:R9udncE02q3BJlrNnZ2dnUVZ snipped-for-privacy@scnresearch.com:
yep. But it's a two-edged blade. Restrict it, and you get less dehumidification when you can use it most, and potentially can freeze the evaporator, if there's too little flow.
All-in-all, it works fine with no restrictions. There's just a limitation on how low a humidity you can accomplish.
And, of course, the usual AC doesn't have a humidistat, so it's just a matter of letting it run continuously, unless you want to do a bit more engineering.
Lloyd
The fact that it's more efficient to move heat to a liquid is reflected in the size of the CONDENSER. The existing air one is much LARGE. The replacment pool water one is much smaller. As long as the temp of the refrigerant when it reaches the air handler is the same, you're not gaining anything in efficiency, except the previously noted issue of using the pool pump motor versus the AC condenser motor. And if you feel the pressure line where it enters the air handler, it's already close to ambient. At least mine is and I would hope it is on any relatively modern AC unit.
As to the water being cooler, if the thing is doing what it's intended to do and claimed to be capable of doing, then it should be keeping the pool 80 to 80F. That doesn't sound very much different from average ambient air temp in locations that need pool heating, in the months when they need it most.
Absolutely agree with the last part.
I never said they were. Only that they are, fairly close. If this thing works, then it should keep the pool at 80 - 85. That isn't all that much different than the ambient air temps when the AC is going to be running. Sure, the pool could be 65 in May. But then the AC isn't running or isn't running enough to make any impact anyway.
That is reflected in the size of the CONDENSER. The existing on is sized based on AIR. The pool water one is sized based on using WATER. So, of course the pool water one is much smaller. But if the temp of the refrigerant when it leaves the condenser and returns to the evaporator in the air handler is the same, then the only thing you've accomplished from an energy standpoint are replacing the fan motor with a pump motor. As previously noted, that is a benefit as long as the pool pump would be running to filter the water anyway.
Yes it does address it, because, again, the refrigerant temp is still going to be about the same temp when it returns to the air handler. Whether it got to that temp by a large air based heat exchanger or a small water based one doesn't matter, the pool pump motor replacing the fan motor being the essential difference.
Anybody can give you "estimates". I'd like to see real data on this pool thing. And as I've said, you do get some savings. It's due to the fact that you no longer have the fan on the condenser running. Instead you're using the pool pump motor, which you can assume is paid for by it having to run for pool filtering, anyway.
Do you have a pool? Pool heater? What size is the pool and what is the pool heater in BTUs? In my world, there is no way this computes.
No it won't. Because the refrigerant temp coming back to the air handler is going to be about the same in either case. The existing condenser is HUGE because it's air based. But it's sized so that the returning refrigerant is near ambient when it goes back. The pool water is going to be typically 80 - 85. At least it would be if this thing does what it's claimed to do. The refrigerant can't go lower than the pool temp, even if this small water based heat exchanger is 100% efficient. So, in my world, the bulk of the energy savings is from the AC condenser fan not running and instead the pool pump being used. The pool pump electricity isn't counted, because the pump would have to run
6 or 8 hours a day to filter anyway.
It ain't gonna do much for SEER, for the reasons noted above.
No way. An inground pool pump pumps in the vicinity of 40 gpm.
The HVAC line through that tiny heat exchanger seems it would have to attain a temperature approaching 1000=B0F to make -any- difference. -----
- gpsman
No it won't. Because the refrigerant temp coming back to the air handler is going to be about the same in either case. The existing condenser is HUGE because it's air based. But it's sized so that the returning refrigerant is near ambient when it goes back. The pool water is going to be typically 80 - 85. At least it would be if this thing does what it's claimed to do. The refrigerant can't go lower than the pool temp, even if this small water based heat exchanger is 100% efficient. So, in my world, the bulk of the energy savings is from the AC condenser fan not running and instead the pool pump being used. The pool pump electricity isn't counted, because the pump would have to run
6 or 8 hours a day to filter anyway.It ain't gonna do much for SEER, for the reasons noted above. =========================================================
I think you missed the basic point.
Heat transfer to air is *intrinsically* less efficient (by orders of magnitude) than it is to water. Add to that that the water is proly sig'ly cooler than the air to begin with, water cooling of the outside coils of an A/C is a no-brainer.
So no matter how the condenser is "sized" for air, a water bath would radically improve (lower) the returning refrigerant temps. And the hotter the day, the more improvement will be seen.
But, HOW this is actually executed is another story, as Vic implied. He was just making the thermodynamic point that, all other things being equal, the A/C efficiency, due to the heat transfer to water instead of air, would skyrocket. That the A/C exhaust fan is not needed is an added plus, as well.
OTHER things might negate the idea of water cooling, but that's another story.
Why do you think IC engines are water-cooled? Despite the fact that air-cooling technology exists? They've even gone to water-cooling motorcycle engines. Yeah, the analogy is not perfect, but it drives the point home.
I never mentioned heating the pool, only AC efficiency. But even with water and air temps the same, water cooling is a much more efficient means to remove heat. Why do you think many commercial enterprises use water cooling for AC? Building logistics, local electric and water costs, and salesmen. Cooling towers aren't put up capriciously.
You seem to be denying common precepts of thermodynamic laws. Energy is being used and transferred in all cases. Water transfers heat much better than does air. Beside the fan, a bigger condenser also usually means a bigger compressor, and more energy use.
You keep saying the end result is same, but it's not. Water cooling will provide lower condensed refrigerant temps with less electrical energy expended. You can cut down a tree with a sharp blade or a dull blade. The tree goes down in either case. But the dull blade will tire you out more.
You probably won't find data on residential pool-cooled AC condensers, because air-cooled AC does the job, electricity is pretty cheap in most places in the U.S., and residential pools are very small in number. The southwest U.S. might be the place to look. Here's a "study" done in Kuwait showing `40% energy savings using water cooled AC. Click on the pdf link.
No, I don't have a pool and never wanted one. And I'm not saying I would cool my AC with pool water. But if I lived in the right climate and had a pool, I would look into it. But a hard look at cost vs savings. Chlorine interaction with the heat exchanger might be the biggest issue, BTW, I don't know who said it, but I think somebody said the air handler uses the bulk of the electric energy in the AC system. Not true from what I've read. Compressor uses `70%.
Another huge problem is the pool chemistry has to be kept Very Rigidly Controlled or the pool water will rot out the water cooled condenser REAL FAST - or clog it up with scale to the point it won't work anymore, same outcome. Most people can't or won't be that anal about the pool water, and the condensers can rot in a year or two.
This is why water cooled condensers and the water tower used to cool the water use liberal amounts of some really nasty chemical additives to keep that from happening - and you sure as hell don't want to swim in them. And they still dump a lot of water and evaporate even more on purpose (higher temps) and replace it with fresh every day.
Plus, you need to setup a variable-speed pool pump motor and link the AC to the Pool - and you'll really need a computer to know when to shift between the Water Condenser and the regular air condenser coils on the condensing unit - Or it can't run automatically.
If you go that way, gotta go all the way or don't bother.
-->--
"Bruce L. Bergman (munged human readable)"
It's not as huge a problem as you think.
For one, a pool should be kept near neutral.
I have a pool heater and years ago, after 2 years, the water manifold developed a leak. The first thing the pool guy was asking is "did you keep the water near neutral?". I did, but was unable to get any kind of discount on the replacement.
When putting in the replacement, I noticed the interior is coated with plastic. So, there's no water to metal contact.
I've been running heaters for more than 6 years now and I can tell you the water in contact with a heated metal unit does not create any special corrosion problems. A condenser shouldn't be any problem at all.
I'm not sure what all the controversy is.
If this guy had his AC unit near his pool pump he just did what was reasonable. The alternative would be to have a big fan roaring near the pool with hot air being blown around. That's not something you want near a pool.
Using water cooling is going to be quieter and save blower energy. I believe other posters are correct, this won't heat the pool much but it will save energy, be quiet, and not heat the air near the pool.
You are correct, from my actual experience.
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