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Air Conditioner Question
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N:dlzc D:aol T:com (dlzc)
science forum Guru


Joined: 25 Mar 2005
Posts: 2835

PostPosted: Tue May 23, 2006 12:30 am    Post subject: Re: Air Conditioner Question Reply with quote

Dear Harry Andreas:

"Harry Andreas" <andreas@computer.org> wrote in message
news:andreas-2205061313060001@147.16.85.59...
Quote:
In article <s_tbg.3800$AB3.60@fed1read02>, "N:dlzc D:aol T:com
\(dlzc\)"
N: dlzc1 D:cox T:net@nospam.com> wrote:

"Harry Andreas" <andreas@computer.org> wrote in message
news:andreas-1905060921250001@147.16.85.59...
In article <VCjbg.3779$AB3.2895@fed1read02>, "N:dlzc D:aol
T:com \(dlzc\)"
N: dlzc1 D:cox T:net@nospam.com> wrote:
...
Insulate the walls, and run chilled water along
the inside of the walls. Then there is no air blowing.

No, there is just condensation all over the walls,
inside

Yep.

and out.

Nope. See where I said to insulate the walls above?

Thermodynamically I assumed that you meant to insulate
the outer walls of the building. Insulating the inner walls
would make no sense. If you are running the cooling loop
inside the wall, then you are depending on conductivity
of the inner wall to get a cold surface to the room.

Then there would be no condensation on the outside, nor would
there be condensation in the emtpy space between the walls (I've
done this in equipment with no outside air exchange).

Quote:
What follows quickly thereafter is mold inside
and outside the walls, follwed by sickness and
maybe death

Consider that the condenser coils in a refrigeration system do
exactly this. Yet "sickness and maybe death" is a rare thing.
The metals of construction probably serve to "poison" most
biogrowth.

First, the cooling coils of a refrigerator have forced air
passing
over them, so they remain more or less dry.

No they do not. I have moisture condensing and dripping off my
evaporator coils.

Quote:
The inside of the wall would not, which would allow
liquid water to form from condensation. Second,
non-sterlie liquid water entrapped in a closed space
will quickly form mold and mildew on any growth
medium present, and there is lots of growth medium
available on a house.

Again, I have standing water under my evaporator coils, and they
are wet. I have no such growth.

Quote:
The metal coils of a refrigerator do not support
mold growth even if they are wet.

Because they are metal, and tend to suppress most biogrowth
(especially at cold temps). The collector pan is not metal.

Quote:
There are lots of sick people around right now
because of mold growth in houses, and don't even
mention New Orleans. Down there the authorities
won't even let workers into some abandoned
houses because of toxic mold contamination, unless
the workers are wearing full Hazmat suits.

Too bad they don't just blow some air-fed ozone in there for
about 30 minutes...

David A. Smith
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John P Bengi4
science forum beginner


Joined: 21 Mar 2006
Posts: 2

PostPosted: Wed May 24, 2006 10:03 pm    Post subject: Re: Air Conditioner Question Reply with quote

<.p.jm@see_my_sig_for_address.com> wrote in message
news:dnfv629fbsvfq6decuj24a5gslptbv3jou@4ax.com...
Quote:
On Sat, 20 May 2006 23:01:46 GMT, "Don A. Gilmore"
eromlignod@kc.rr.com> wrote:

.p.jm@see_my_sig_for_address.com> wrote in message
news:4tuu62dtovjnfpqh5pk4vnm4metee8e67k@4ax.com...
On Sat, 20 May 2006 20:25:48 GMT, "Don A. Gilmore"
eromlignod@kc.rr.com> wrote:


.p.jm@see_my_sig_for_address.com> wrote in message
news:g9eu62h4uu5v9r33qtleqrongto6t5i1r8@4ax.com...
On Sat, 20 May 2006 15:37:27 GMT, "Don A. Gilmore"
eromlignod@kc.rr.com> wrote:

"Paul O" <first.d.last@company.com> wrote in message
news:e4na6h$aat$1@boulder.noaa.gov...
David,
I like this idea! It would be a great way to to cool a
greenhouse or
an
indoor temperate rain forest exhibit! The waterfall would
lower the
ambient temperature while keeping the humidity high.


It would *lower* the humidity.

It depends entirely on the temperature of the water, and the
dew point of the air it interacts with.


No, it works just like your refrigerator or your car's windshield
defogger.

WTF are you talking about ?

It dehumidifies the air by condensing water out on the cold
surface, just
like an evaporator.

No s**t. Now explain how a refrigerator and a windshield
defogger work in the same way ??????

It would seem like the colder interior air would
approach the dew point causing a higher relative humidity (that
is, if no
water were removed), but it doesn't work that way. The evaporator
condenses
more water out than the dew point can keep up with, or than will
re-evaporate back into the air from the evaporator catch pan.
Vapor
compression refrigeration always *lowers* the RH of the contained
air.

Wrong. Utterly totally wrong.

Here, study this :

A room is at

DB 80.0 F
WB 60.2 F
Dew 45.8 F
RH 30.0 %

I run an evaporator at 50 % F coil temp.

Think about what happens. To room gets cooler, the RH goes **
UP **. ** NO ** moisture is removed from the air.

Before you say 'this is some kind of theoretical example that
never happens in real life', go study the weather in Phoenix AZ.

This
drying effect often has to be taken into account when designing
such
systems.

You need to back to school, first year, and start with the
basics. Learn about something called 'psychrometrics'.

After you save up some, you can maybe afford to purchase one
of the programs I wrote on the subject.

Then try to study the advanced concept of 'chilled water
DEhumidification, which was the topic here.


Heh, calm down, kid. Nobody's talking about your mother.

I just did a little experiment for you. I have a digital
hygrometer. I put
it on the table here and it says that the humidity in this room is
40% at a
temperature of 78 degrees (I have the windows open today). That
agrees with
what the weather service says for Kansas City. I put the same
hygrometer in
my refrigerator for five minutes. When I take it out it reads 11%
humidity
and 41 deg. F, just as I would have expected.

Try it yourself sometime.

I'me very happy for you.

What in the f*** does that have to do with anything I said, or
anything in this thread ? Other than perhaps your own incorrect
statements, for which you have now provided a non-proof ?


Don
Kansas City


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huh?
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Guido
science forum beginner


Joined: 04 May 2005
Posts: 2

PostPosted: Fri Jun 09, 2006 3:01 pm    Post subject: Re: Air Conditioner Question Reply with quote

Paul O wrote:
Quote:
N:dlzc D:aol T:com (dlzc) wrote:

snip

Insulate the walls, and run chilled water along the inside of the
walls. Then there is no air blowing.

Oops. Not a bad idea except you would have to keep the fluid in the
walls above the dewpoint in temp. Which in a house would be impossible.
This system is used in europe with chilled beam ceilings.

Air is blown from a main AHU across a chilled beam and diffuses into
the room. However we dehumidifi the air coming into the building to
around 40 % RH this way the extract dew point temp rarely gets above 12
DegC.

Bye.
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N:dlzc D:aol T:com (dlzc)
science forum Guru


Joined: 25 Mar 2005
Posts: 2835

PostPosted: Sat Jun 10, 2006 3:46 am    Post subject: Re: Air Conditioner Question Reply with quote

Dear Guido:

"Guido" <parkinsonimpact@aol.com> wrote in message
news:1149865268.969659.124880@i40g2000cwc.googlegroups.com...
Quote:

Paul O wrote:
N:dlzc D:aol T:com (dlzc) wrote:

snip

Insulate the walls, and run chilled water along
the inside of the walls. Then there is no air
blowing.

Oops. Not a bad idea except you would have to
keep the fluid in the walls above the dewpoint in
temp. Which in a house would be impossible.

It would be possible. I have a "wetwall" in my shower. It would
simply be "ugly" to have a huge wall with a floor drain. In
every room.

Quote:
This system is used in europe with chilled
beam ceilings.

Air is blown from a main AHU across a chilled
beam and diffuses into the room. However we
dehumidifi the air coming into the building to
around 40 % RH this way the extract dew point
temp rarely gets above 12 DegC.

Bye.

Thanks. In Russia, they do a similar thing, only with heating...
so condensation is never a problem.

David A. Smith
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Sun Jun 18, 2006 5:52 am    Post subject: Re: Air Conditioner Question Reply with quote

Quote:
Insulate the walls, and run chilled water along the inside of the
walls. Then there is no air blowing.

Oops. Not a bad idea except you would have to keep the fluid in the
walls above the dewpoint in temp.

VERY doable in some places.


Bret Cahill
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Bret Cahill
science forum Guru


Joined: 05 May 2005
Posts: 480

PostPosted: Sun Jun 18, 2006 6:02 am    Post subject: Re: Air Conditioner Question Reply with quote

Quote:
it sounds to me like the real answer to my
question is, it is too expensive to make an air conditioner that can run
efficiently at a wide range of outputs.

It might not be all that expensive ONCE IT WAS DESIGNED but the problem
is most engineers are quite happy to find ONE design point that is
efficient so it is easier to just shut the thing on and off than screw
around with an INFINITE number of design points.


Bret Cahill
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CJT
science forum beginner


Joined: 19 Jun 2006
Posts: 4

PostPosted: Sun Jun 18, 2006 6:53 am    Post subject: Re: Air Conditioner Question Reply with quote

Bret Cahill wrote:

Quote:
Insulate the walls, and run chilled water along the inside of the
walls. Then there is no air blowing.


Oops. Not a bad idea except you would have to keep the fluid in the
walls above the dewpoint in temp.


VERY doable in some places.


Bret Cahill

Very dewable Smile in others.


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