"Vic Smith" wrote in message
...
On Wed, 12 Dec 2012 05:19:15 -0800 (PST), "
wrote:

On Dec 10, 12:38 pm, Vic Smith
wrote:
On Mon, 10 Dec 2012 07:43:07 -0800 (PST), "

wrote:

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.

"Ambient" pool water temperature normally isn't the same as ambient
air temp.

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.


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.



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.

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.


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.



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.

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.

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.



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.

I've seen estimates that water cooled condensers give 20-50% energy
savings.

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.


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.
http://repository.tamu.edu//handle/1969.1/4621
I don't vouch for it.

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.

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, 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%.

All true (proly).
But Trader's point was, if the return refrigerent is already at ambient temp
(and assuming water is at the same ambient temp), adding water cooling to an
existing system will provide no benefit. This is correct.
I don't know if return refridgerant of an air-cooled A/C *is* at ambient
temps, but if it is, ADDING water coolant won't do anything further.

If the pool water is below ambient temp, then better effic would be
realized, but it would remain to be seen if the increased effic was worth
the monkeying around.

But, from an original design pov, water (or whatever the liquid coolant)
will undoubtedly allow the inherent design of the system to be more
efficient.

Energy usage:
In my 5 ton A/C unit, the blower draws about 10 A at 120 V, the
compressor 20 A at 240, for a total of 6,000 W. 4800/6000 = 80%. 6,000
W.... holy ****....

And if the fukn installer -- Yost & Cambpell, Westchester, Bronx, NYC,
NY -- didn't **** up the installation so royally, the blower could have been
under 5 A instead of over 10 A, so the compressor usage ratio would have
been higher. In fact, the original blower WAS under 5 A..... **** Yost &
Campbell, the worst HVAC company I've ever seen.

Inway, I don't know if that ratio holds in commercial buildings, etc, but my
installation supports your figure.
--
EA