It's typically within a couple degress of ambient. If it's higher than a
couple degrees, I know there is other problems going on. That;s one of the
things I check on systems that aren't working.

Christopher A. Young
Learn more about Jesus
www.lds.org
..

wrote in message
...

If someone here is in a warm climate, has a decent efficient
AC system, perhaps they could measure the temp of the
refrigerant pressure line just before it enters the air handler.
I'd love to do it, but it's too cold here. It would be interesting
to see how much above outside ambient the temp is.

On Dec 13, 2:19*pm, Vic Smith wrote:
On Thu, 13 Dec 2012 07:53:13 -0800 (PST), "

wrote:

You need to get a grasp on efficiency and what it
actually means. * In this case, the fact that water can
absorb a lot more heat than air means that you can
use a much smaller heat exchanger with water to
transfer the SAME amount of heat. * That is why the
pool heat exchanger is SMALL, the AC condenser
with all it's coils on 4 sides is LARGE.

Right. *Water cooling means a smaller condenser, a smaller compressor
and compressor motor, and `30% less electrical consumption than an
air-cooled unit producing the same cooling capacity.
But that has nothing to do with efficiency. *And all the HVAC
engineers are wrong. *And I "need to get a grasp on efficiency .."
Got it. *Dream on.


Tthere is no such thing as just "water cooling".
You have to look at the whole system, how it's sized,
what temp the water source is, where the heat from
the water goes, what temp the water is when it
returns, etc.

Let's start with the basics of that home AC as it
currently works, with air being used to transfer heat at
the outside condenser, OK?
The refrigerant comes into the air handler evaporator
as a liquid. Let's say it's 85F. It expands, cooling the air.
When it leaves
the evaporator it's a gas and cold, let's say 40F.
The compressor draws it back via the suction line.
The refrigerant gas enters the compressor and gets
compressed back into a liquid. In doing so, it's temp
rises substantially. That's most of the energy
consumption right there, compressing the refrigerant.
Now it's a liquid again, at 140F.
Now we have to get rid of that heat, cool it down.
Are you with me so far? We're going to cool it down.
We can do that in one of two ways:

A - Pass it through a larger heat exchanger which is a coil with
ambient air flowing over it.

B- Pass it through a smaller heat exchanger with pool
water flowing over it.

In case A, the governing factors that effect the efficiency
are the electricity that it takes to run the fan and the
temperature of the air. The refrigerant can't be cooled
below the temp of the ambient air, but with a properly
sized coil and fan, we can get it close to that.

In case B, the governing factors that effect the efficiency
are the electricity it takes to run the pool pump and the
temperature of the pool water. The refrigerant can't be
cooled below the temp of the pool water, but with a
properly sized coil and fan, we can get it close to that.

That is the essential energy difference. Now let's say
that the ambient air is 80F and the pool water is also 80F.
In that case it's perfectly possible and reasonable to get
the refrigerant down to close to 80F using either approach.
Now the cooled refrigerant at 85F goes back to the evaporator
at the air handler. It enters the evaporator,
expands, cools the air and leaves the evaporator at 40F,
completing one whole cycle. That's it.

So, the cycle works exactly the same either way.
You still need the same size compressor motor.
You still get the same cooling capacity. The only
difference is that you've used a large air based
heat exchanger with an electric fan in one case and
a much smaller water based heat exchanger with an
electric pool pump in the other.

Now, if you attribute the pool pump motor
electricity to the pool operation instead of the AC,
which is reasonable, then you can say you've
"saved" the cost of running the air fan in the AC
condenser. That's reasonable. And you could say
that the system is saving x percent in energy because
it no longer has the AC fan running. Actually, now
that I think about it, I wonder if the fan isn't really
running all the time anyway. Because to stop it is going to
require modifying the AC electrical system. Every one I've
seen the fan runs when the compressor runs.

But otherwise, the operation of the system is
EXACTLY the same whether you air cool it or water
cool it. I don't see a magical
improvement in efficiency, no smaller compressor, etc.
In fact, it's bizarre to drag a smaller compressor into this
at all, because no one is proposing to change the size
of the compressor in the home AC, are they? Could
I design a water based system, with a smaller compressor,
less electricity? sure. Just use ground water that is
50F. But that isn't what we're talking about doing here.

Now, in actuality, the temp of the refrigerant going back
to the evaporator may be slightly lower with the pool
water based system. But IMO, it's not going to be so
much lower that it makes a significant difference. And
it can't be lower than the pool temp water, no matter
what. If the thing is doing what it's supposed to be doing
in the TOH application, then the pool water should be
about 80 - 85 most of the time, ie not much different
than ambient.

And the returning refrigerant temp can't be too much
above 85F, ie ambient, because obviously
the existing system has a properly sized air based
heat exchanger to take away as much of the heat as
possible, ie get it down close to ambient. That's one
of the ways to get higher SEERs out of the system
and it would be pretty dumb to be selling systems that
don't bring the temp of the refrigerant down as close
as possible to ambient when
you can do it by just using a bigger condenser, more
airflow from the fan, etc.

That's the physics as I see it.

First the use of isolation reservoirs are very common.

One pumps hot coolant into a tank of say salt solution but keep all of
the coolant in the pipe. In another loop that goes in the tank and
outside of the system - is other coolant. So coolant A never touches or
mixes with coolant B.

One is drawing heat off and putting it into the salt. The other takes
the heat from the salt and dumps it in the pool or in a water cooled
chiller.

Many machines work that way and every NUKE works that way as well.

Martin

On 12/13/2012 9:30 AM, wrote:
On Dec 12, 4:08 pm, Dan Espen wrote:
"Bruce L. Bergman (munged human readable)"

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.

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.

--
Dan Espen

If you watch the TOH video, the problem was not
the AC condenser unit making noise. It did not appear to be
particularly close to the pool. The problem was the pool is
shady and the homeowner wanted to heat the pool. The side
benefit was the alleged substantial savings in AC costs.

First the use of isolation reservoirs are very common.

One pumps hot coolant into a tank of say salt solution but keep all of
the coolant in the pipe. In another loop that goes in the tank and
outside of the system - is other coolant. So coolant A never touches or
mixes with coolant B.

One is drawing heat off and putting it into the salt. The other takes
the heat from the salt and dumps it in the pool or in a water cooled
chiller.

Many machines work that way and every NUKE works that way as well.

Simply put the solution you want in place of the efficient salt.

Martin

On 12/13/2012 9:30 AM, wrote:
On Dec 12, 4:08 pm, Dan Espen wrote:
"Bruce L. Bergman (munged human readable)"

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.

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.

--
Dan Espen

If you watch the TOH video, the problem was not
the AC condenser unit making noise. It did not appear to be
particularly close to the pool. The problem was the pool is
shady and the homeowner wanted to heat the pool. The side
benefit was the alleged substantial savings in AC costs.

" writes:

That is the essential energy difference. Now let's say
that the ambient air is 80F and the pool water is also 80F.

I've seen this stated a few times in this thread and I don't think it's
true. The pool temperature is going to be the average of daytime and
nighttime temperature plus the effect of evaporative cooling at the
water surface, plus the effect of cooling due to ground temperature.

All and all, I'd expect the pool water during the time the AC is in use
to be significantly lower than the air temperature.

Before I had my heater, with air temps in the upper 90s I'd still have
the water at 80 or so. If I remember right, 82 was an all time high.

The heating from the AC system heat exchanger isn't going to make much
of a difference for pool temperature but the AC system will cool better.

--
Dan Espen

On Dec 14, 12:55*pm, Dan Espen wrote:
" writes:
That is the essential energy difference. * Now let's say
that the ambient air is 80F and the pool water is also 80F.

I've seen this stated a few times in this thread and I don't think it's
true. The pool temperature is going to be the average of daytime and
nighttime temperature plus the effect of evaporative cooling at the
water surface, plus the effect of cooling due to ground temperature.

All and all, I'd expect the pool water during the time the AC is in use
to be significantly lower than the air temperature.






Before I had my heater, with air temps in the upper 90s I'd still have
the water at 80 or so. *If I remember right, 82 was an all time high.

That depends on the particular climate and if the pool is
shaded or full sun. Here in NJ/NYC for example, pools that
have mostly sun are in the low 80s
without heat during July and Aug. And that is with daytime
temps in the 80s. If it's upper 90s for a couple days, pool
could be 85+ with no heater. The time folks here typically
use a pool heater, if at all, is in the beginning of the season, ie
late May, early June and again going into Sept. The
problem with that is during those periods the AC is
running the least. It's a mismatch between when it's
needed most and when the most heat is available.

I agree there are going to be some days when the pool
water temp will be below the air temp. But look at it
from this perspective. If the system works to do what
is wanted, then the pool should be 80+, no? Isn't that
a purpose of the pool heater? So, if the water is 80 - 85,
reagardless of how it gets there, I don't see that as being
a big difference versus the ambient air if you average
it out. For example, at night, the pool at times could
actually be above the ambient air temp, right?
If you;re saying, well the pool could be 75 and the
ambient air 90, sure I could see that, but that situation
has to be an exception, or else the thing isn't heating
the pool enough, right? If it's working, then you
should have 90 air, 85 water.





The heating from the AC system heat exchanger isn't going to make much
of a difference for pool temperature but the AC system will cool better.

--
Dan Espen

But the main point of the whole TOH project was to
heat the pool. That was the original problem, not that
they wanted to lower the AC bill. The lowering of the
AC bill was an additional benefit.

" writes:

On Dec 14, 12:55Â*pm, Dan Espen wrote:
" writes:
That is the essential energy difference. Â* Now let's say
that the ambient air is 80F and the pool water is also 80F.

I've seen this stated a few times in this thread and I don't think it's
true. The pool temperature is going to be the average of daytime and
nighttime temperature plus the effect of evaporative cooling at the
water surface, plus the effect of cooling due to ground temperature.

All and all, I'd expect the pool water during the time the AC is in use
to be significantly lower than the air temperature.

Before I had my heater, with air temps in the upper 90s I'd still have
the water at 80 or so. Â*If I remember right, 82 was an all time high.

That depends on the particular climate and if the pool is
shaded or full sun. Here in NJ/NYC for example, pools that
have mostly sun are in the low 80s
without heat during July and Aug. And that is with daytime
temps in the 80s. If it's upper 90s for a couple days, pool
could be 85+ with no heater. The time folks here typically
use a pool heater, if at all, is in the beginning of the season, ie
late May, early June and again going into Sept. The
problem with that is during those periods the AC is
running the least. It's a mismatch between when it's
needed most and when the most heat is available.

I agree there are going to be some days when the pool
water temp will be below the air temp. But look at it
from this perspective. If the system works to do what
is wanted, then the pool should be 80+, no? Isn't that
a purpose of the pool heater? So, if the water is 80 - 85,
reagardless of how it gets there, I don't see that as being
a big difference versus the ambient air if you average
it out. For example, at night, the pool at times could
actually be above the ambient air temp, right?
If you;re saying, well the pool could be 75 and the
ambient air 90, sure I could see that, but that situation
has to be an exception, or else the thing isn't heating
the pool enough, right? If it's working, then you
should have 90 air, 85 water.

I have no delusion that this thing heats the pool to any significant
temperature.

The heating from the AC system heat exchanger isn't going to make much
of a difference for pool temperature but the AC system will cool better.

But the main point of the whole TOH project was to
heat the pool. That was the original problem, not that
they wanted to lower the AC bill. The lowering of the
AC bill was an additional benefit.

TOH never said heating the pool was the _main_ point at least I didn't
catch it. Maybe they mentioned pool heating first?

I think they were wrong to mention pool heating at all because
this isn't going to heat the pool enough to make a difference.

I'm in central NJ (like you).

I didn't see where they mentioned the location of the house in question but
since it's TOH, it's likely it's New England. Like us in NJ, only
worse. With the trees that guy had next to the pool, that water must be
freezing. Reminds me of swimming in the cold clear lakes of New
England. Nice water but cold, cold, cold.

--
Dan Espen

On Dec 14, 3:15*pm, Dan Espen wrote:
" writes:
On Dec 14, 12:55*pm, Dan Espen wrote:
" writes:
That is the essential energy difference. * Now let's say
that the ambient air is 80F and the pool water is also 80F.

I've seen this stated a few times in this thread and I don't think it's
true. The pool temperature is going to be the average of daytime and
nighttime temperature plus the effect of evaporative cooling at the
water surface, plus the effect of cooling due to ground temperature.

All and all, I'd expect the pool water during the time the AC is in use
to be significantly lower than the air temperature.

Before I had my heater, with air temps in the upper 90s I'd still have
the water at 80 or so. *If I remember right, 82 was an all time high..

That depends on the particular climate and if the pool is
shaded or full sun. * Here in NJ/NYC for example, pools that
have mostly sun are in the low 80s
without heat during July and Aug. *And that is with daytime
temps in the 80s. *If it's upper 90s for a couple days, pool
could be 85+ with no heater. *The time folks here typically
use a pool heater, if at all, is in the beginning of the season, ie
late May, early June and again going into Sept. * The
problem with that is during those periods the AC is
running the least. *It's a mismatch between when it's
needed most and when the most heat is available.

I agree there are going to be some days when the pool
water temp will be below the air temp. *But look at it
from this perspective. *If the system works to do what
is wanted, then the pool should be 80+, no? *Isn't that
a purpose of the pool heater? *So, if the water is 80 - 85,
reagardless of how it gets there, I don't see that as being
a big difference versus the ambient air if you average
it out. *For example, at night, the pool at times could
actually be above the ambient air temp, right?
If you;re saying, well the pool could be 75 and the
ambient air 90, sure I could see that, but that situation
has to be an exception, or else the thing isn't heating
the pool enough, right? *If it's working, then you
should have 90 air, 85 water.

I have no delusion that this thing heats the pool to any significant
temperature.

The heating from the AC system heat exchanger isn't going to make much
of a difference for pool temperature but the AC system will cool better.