Heating a pool with an air conditioner

[gpsman]

Via the AC, which is obviously woefully insufficient to heat the standard 16x32 =B120K gallon pool.

Seems it must be a system auxiliary to a dedicated heater. -----

- gpsman

[trader4]

After posting this, I realized there was one aspect I overlooked. I compared the electricity to run the pool pump with the electricity to run the pool pump. But the electricity used by the pool pump can probably be ignored because the pool pump typically runs 6 or

8 hours a day to filter the pool water anyway. So, it can be filtering while doing the AC.

In which case, I can see the system saving basicly whatever it took to run the fan motor on the AC condenser. Which is something. But the whole thing appears very impractical to me for a variety of reasons. The biggest obstacle being the mismatch between the periods when you need it most and when the AC is actually running the most. For example, here in NJ, when the heating is most useful is late May and June at the beginning of the season and Sept to extend the season for a few weeks. Those times the AC is not running all that much.

[gonjah]

>

I think this is the episode. It's the 3rd scene selection:

Titanium.

FWIW: My pool heaters heat exchangers are copper.

[gonjah]

I just watched it and it sounds like it's both. It does make very good sense. Apparently it's nothing new.

(3rd scene)

Thanks for posting BTW. It sure gives me something to think about.

[trader4]

No, on this TOH show it was installed as the only heater for a pool in a shaded area. I certainly could be used in conjuction with another pool heater though. But still, IMO, a dumb idea. One of those being, as you say, that the amount of heat it takes to heat a typical inground pool vs the amount of heat available, at the times of year you need it, does not seem to compute.

I'd love to hear a follow up report on how well it works. Funny that they didn't do anything like that.... Like turn it on and see how much if warms the pool over a few days.

[gpsman]

I had to view a couple minutes online to see if the pool was in Hawaii, the online version seemed to skip that part.

It seems they need heat in summer, as do we. I suppose if the heat is constantly applied day after day it might eventually provide a few more degrees where a few more makes a big difference between too cold and tolerable, but even that seems unlikely unless some type of super solar blanket is used to keep all that surface area from dissipating the heat.

I don't think that little ~2 gallon heat exchanger is going to win that race unless the ambient air temp. is ~100F 18 hours a day falling to 90 at night. -----

- gpsman

[gonjah]

I think no matter how you view it it's going to be a real close call. I don't know enough about HVAC to understand how it makes the AC more efficient, but he claims it does.

With my pool, the pool plumbing is on one side of the house and the compressor is on the other making plumbing a real problem. I'd have to dig and make some additional input/outputs or run plumbing all the way to the pump. Doesn't seem to make much sense in my situation. But I am interested in lowering my AC costs. The money would probably be better spent on additional insulation.

[homeowner]

Isn't the purpose of a pool to cool off in hot weather? What's the point in heating it?

Sounds to me like another useless gadget to steal people's money......

[peace and love]

Sort of. When it's hot out (90+ degrees F) some pools still only get into the high 70's and low 80's depending on the amount of sunlight. My pool, when it's exposed to full sun, doesn't need any help. But, if you watch the video, he says this pool gets little sunlight. Some people want the pool in the high 80's. In that case it might push it up a few degrees. Plus he says it helps the AC, which would be my main concern.

Does it steal money? Maybe. I'd like to see some real stats before I invested. Plus. Your pool pump and condenser would need to be in the same location. That doesn't seem to be real likely unless you built your pool and a/c accordingly. In my case, it's pretty much out-of-the-question.

[Existential Angst]

You may not have a pool, but I say you're on the right track. You're right, durintg the times you are most likely to want to heat the pool, the AC will not be running much. When the AC is running a lot, you're not likely to need it much to warm the pool. Here in NJ the AC is running a lot in Jul and Aug, precisely the time you typically don't need to heat the pool.

Also take a look at the BTUs of a typical pool heater. I have one here that is gas, 400K BTUs for a 48,000 gal pool. You can scale that for other sizes. They don't put 400K btu heaters in for nothing. It takes a hell of a lot of energy to heat all that water. A 4 ton AC by comparison is only 48,000 BTUs, an order of magnitude smaller ====================================================

Wow.... 400K btu's is a lot.... This might be an idear unique to your situration, but why don't you build a hot-air type heat exchanger for your pool, and just *talk* into it?? I'll bet your gas bill will drop to zero, and your pool temps will climb to, like, 110 F..... On a particularly loquacious day, you might be able to heat your neighbors' pools as well.....

[trader4]

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D

If you don't have something to contribute, I suggest you just not post, instead of hurling insults for no reason.

[trader4]

Close? Close to what? Nothing I've seen suggests it's feasible for heating a pool, when and where you need to heat a pool.

I

It eliminates the fan in the condenser unit, using the pool pump instead. The pool needs to be filtered for 6 - 8 hours a day anyway, so that pool pump electricity is already paid for.

I say if it's right next to the pool eqpt, like in the video, it's still nuts. And what does it cost to install that thing? Unless you DIY, you need a pool tech, an HVAC tech, and an electrician. And then let's say the AC system isn't working right. You call an AC tech. They have never seen anything like this. In my experience, you're lucky enough to get one that understands and can correctly diagnose a standard system.

[trader4]

Think about how it could help the AC. The current coils and fan in the condesner are perfectly capable of taking the heated, compressed refrigerant down to close to ambient temperature. The pool heat exchanger is going to do the same thing. Yeah, it's smaller because water can take the same heat away with a smaller heat exchanger. But, at the end of the day, all I see that's saved is the cost of running the AC condenser fan. Don't know how much that is in the whole AC scheme, but considering you have a compressor, big blower in the furnace, I'd be surprised if it's more than 15% or so.

Me too. You would think TOH would come back a week later to show the results.

[gonjah]

Yeah. Good points.

[Vic Smith]

"Ambient" pool water temperature normally isn't the same as ambient air temp. A pool provides an enormous heat sink, cooling at night, with evaporative cooling not requiring jumping through EPA hoops. Water is thousands (WAG) of times more capable of removing heat than air. And "perfectly capable" doesn't address the difference in time running to do the same job. Which gets to electrical consumption and compresser/fan wear.

I've seen estimates that water cooled condensers give 20-50% energy savings. It's all in the details - and climate. In some climates people want their pools chilled. Barring that, using pool water to cool the condenser is elegant and efficient if the bottom line works out The main issues are initial cost and maintenance. Those are the nuts to crack. It all gets to payback.

[Robert Neville]

It's also more efficient to move heat to a liquid rather than the air, plus most of the time the water is going to be cooler than the air when the a/c is running, another reason the a/c will be slightly more efficient.

That said, if you are going into this kind of setup thinking it will save you money in heating a pool, you need a refresher course in basic thermodynamics. Then look at what a PITA combo VCR/TVs were and consider what you'd be dealing with with your average HVAC tech.

[Existential Angst]

Excellent points. Bottom line, the pool will help the A/C MUCH more than the A/C will help the pool. BUT, it is proly unlikely this could be done economically, at least in a one-off basis.

But, if A/C mfrs would outfit the condensing heat exchanger with a water jacket, so that all's you needed was some fittings, plastic tubing and a small-ish pump, then indeed it would be economical, and likely radically increasing the SEER ratings.

[Lloyd E. Sponenburgh]

"Existential Angst" fired this volley in news:50c6fa9f$0$24777$ [e-mail]:

Yeah, but then they wouldn't work with air. There has to be intimate contact between the condensor tubing and the exchange medium.

If they were to outfit them with "Siamese" condensor tubing, so one line carried refrigerant, and the other a liquid exchange medium, AND put fins on the array -- then it would work, but would be quite a bit more expensive.

On a side note: With a little re-wiring of the controls, a large window unit AC makes a dandy monster-scale dehumidifier. Just situate the whole affair inside the conditioned space (instead of through a window or wall), and run the condensate outside. The wasted energy also heats the space (some).

I have dehumidified large industrial drying rooms for cheap that way.

Lloyd

[Transition Zone]

a9f$0$24777$ [e-mail]:

Does the evaporator still run cold? And if not, does any water condense inside of the unit (as the inside area's air is on its way out)?

[Transition Zone]

6fa9f$0$24777$ [e-mail]:

Oops, didn't read that. You ran the thing with the windows closed.