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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: Sat May 20, 2006 1:08 am    Post subject: Re: Air Conditioner Question Reply with quote

Dear Harry Andreas:

"Harry Andreas" <andreas@computer.org> wrote in message
news:andreas-1905060921250001@147.16.85.59...
Quote:
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.

Quote:
and out.

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

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.

David A. Smith
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N:dlzc D:aol T:com (dlzc)
science forum Guru


Joined: 25 Mar 2005
Posts: 2835

PostPosted: Sat May 20, 2006 1:13 am    Post subject: Re: Air Conditioner Question Reply with quote

To the Group:

Quote:
Dear Chris W:

"Chris W" <1qazse4@cox.net> wrote in message
news:Hwdbg.33280$9c6.21170@dukeread11...
...
Anyway, I think I would have the same problem
on really hot days. I hate having the cold air
blow on me. I guess the only solution is to
somehow diffuse the air, by having bigger or
more vents, so it doesn't move so fast.

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

So the consensus is that this is a bad idea.

How about a wall-sized waterfall? Chilled water, turned on when
the room is to be cooled. The humidity in the room will be near
the set point of the water temp. And the moving water will be a
driver for air flow. Not the most efficient system perhaps...
also only a single-room solution. But the air is constantly
cleaned, kept at more-or-less constant humidity, and no directed
cold air stream.

David A. Smith
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Paul O
science forum beginner


Joined: 01 Feb 2006
Posts: 11

PostPosted: Sat May 20, 2006 2:47 pm    Post subject: Re: Air Conditioner Question Reply with quote

N:dlzc D:aol T:com (dlzc) wrote:
Quote:
To the Group:

Dear Chris W:

"Chris W" <1qazse4@cox.net> wrote in message
news:Hwdbg.33280$9c6.21170@dukeread11...
...
Anyway, I think I would have the same problem
on really hot days. I hate having the cold air
blow on me. I guess the only solution is to
somehow diffuse the air, by having bigger or
more vents, so it doesn't move so fast.
Insulate the walls, and run chilled water along
the inside of the walls. Then there is no air blowing.

So the consensus is that this is a bad idea.

How about a wall-sized waterfall? Chilled water, turned on when
the room is to be cooled. The humidity in the room will be near
the set point of the water temp. And the moving water will be a
driver for air flow. Not the most efficient system perhaps...
also only a single-room solution. But the air is constantly
cleaned, kept at more-or-less constant humidity, and no directed
cold air stream.

David A. Smith



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.

Unfortunately, this would be a poor way to cool and office or a house.
The main benefit of air conditioning is that it removes humidity from
the air. I don't know about you, but I'm more comfortable in warm dry
environment than a cool damp environment.

I live in Virginia where hot, humid summers are the norm. Comfort is
all about the dew point. ;-)

I wish I lived near Sante Fe, NM.

Paul D Oosterhout
I work for SAIC
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Don A. Gilmore
science forum beginner


Joined: 24 Mar 2005
Posts: 48

PostPosted: Sat May 20, 2006 3:37 pm    Post subject: Re: Air Conditioner Question Reply with quote

"Paul O" <first.d.last@company.com> wrote in message
news:e4na6h$aat$1@boulder.noaa.gov...
Quote:
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. Where do you think the water comes from?

Don
Kansas City
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.p.jm@see_my_sig_for_addr
science forum beginner


Joined: 12 May 2006
Posts: 4

PostPosted: Sat May 20, 2006 3:44 pm    Post subject: Re: Air Conditioner Question Reply with quote

On Sat, 20 May 2006 15:37:27 GMT, "Don A. Gilmore"
<eromlignod@kc.rr.com> wrote:

Quote:
"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.


Quote:
Where do you think the water comes from?

Don
Kansas City


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
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N:dlzc D:aol T:com (dlzc)
science forum Guru


Joined: 25 Mar 2005
Posts: 2835

PostPosted: Sat May 20, 2006 4:27 pm    Post subject: Re: Air Conditioner Question Reply with quote

Dear .p.jm:

<.p.jm@see_my_sig_for_address.com> wrote in message
news:g9eu62h4uu5v9r33qtleqrongto6t5i1r8@4ax.com...
Quote:
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.

Yes. You could moderate the humidity in the room from as low a
dew point as "40 deg F" (give or take) to as high as you wanted.
And still cool the room, and filter the air.

Might be a bad thing to hear running water in the night though...
makes some people have to pee. ;>)

In fact you could do this all in an enclosed chamber, spray the
water "across" a forced air stream, and distribute the flow
through the house. No air filters required, but you would have
to treat (or refresh/blowdown) the water. If you were removing
water from the air, like in Virginia or Florida, you'd also need
a sewer connection (or send it to the yard).

David A. Smith
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Don A. Gilmore
science forum beginner


Joined: 24 Mar 2005
Posts: 48

PostPosted: Sat May 20, 2006 8:25 pm    Post subject: Re: Air Conditioner Question Reply with quote

<.p.jm@see_my_sig_for_address.com> wrote in message
news:g9eu62h4uu5v9r33qtleqrongto6t5i1r8@4ax.com...
Quote:
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.
It dehumidifies the air by condensing water out on the cold surface, just
like an evaporator. 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. This
drying effect often has to be taken into account when designing such
systems.

Don
Kansas City
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.p.jm@see_my_sig_for_addr
science forum beginner


Joined: 12 May 2006
Posts: 4

PostPosted: Sat May 20, 2006 8:36 pm    Post subject: Re: Air Conditioner Question Reply with quote

On Sat, 20 May 2006 20:25:48 GMT, "Don A. Gilmore"
<eromlignod@kc.rr.com> wrote:

Quote:

.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 ?

Quote:
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 ??????

Quote:
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.

Quote:
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.


Quote:

Don
Kansas City


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Back to top
Don A. Gilmore
science forum beginner


Joined: 24 Mar 2005
Posts: 48

PostPosted: Sat May 20, 2006 11:01 pm    Post subject: Re: Air Conditioner Question Reply with quote

<.p.jm@see_my_sig_for_address.com> wrote in message
news:4tuu62dtovjnfpqh5pk4vnm4metee8e67k@4ax.com...
Quote:
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.

Don
Kansas City
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.p.jm@see_my_sig_for_addr
science forum beginner


Joined: 12 May 2006
Posts: 4

PostPosted: Sun May 21, 2006 1:15 am    Post subject: Re: Air Conditioner Question Reply with quote

On Sat, 20 May 2006 23:01:46 GMT, "Don A. Gilmore"
<eromlignod@kc.rr.com> wrote:

Quote:
.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 ?

Quote:

Don
Kansas City


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Back to top
Herman Family
science forum Guru Wannabe


Joined: 14 Jun 2005
Posts: 173

PostPosted: Sun May 21, 2006 2:53 am    Post subject: Re: Air Conditioner Question Reply with quote

<.p.jm@see_my_sig_for_address.com> wrote in message
news:4tuu62dtovjnfpqh5pk4vnm4metee8e67k@4ax.com...
Quote:
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.



Don
Kansas City


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

I agree with the idea that the humidity will drop. If the room is going to
be cooled by the waterfall, then the waterfall is at a lower temperature
than the room. It will enforce a relative humidity of 100 percent next to
it, but the actuall grains of water per cubic foot will be much lower, and
hence the maximum partial pressure of water will be less there. Since the
water vapor in the room will diffuse to maintain the same partial pressure,
more vapor will be drawn to the area near the waterfall, where it will
condense (because it exceeds the carrying capacity of cold air). The net
effect is that the room loses humidity. Pretty nifty.

Michael
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.p.jm@see_my_sig_for_addr
science forum beginner


Joined: 12 May 2006
Posts: 4

PostPosted: Sun May 21, 2006 3:07 am    Post subject: Re: Air Conditioner Question Reply with quote

On Sun, 21 May 2006 02:53:54 GMT, "Herman Family"
<ecalptsudwaseht.in.reverse@frontiernet.net> wrote:

Quote:

.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.



Don
Kansas City

I agree with the idea that the humidity will drop. If the room is going to
be cooled by the waterfall, then the waterfall is at a lower temperature
than the room. It will enforce a relative humidity of 100 percent next to
it, but the actuall grains of water per cubic foot will be much lower, and
hence the maximum partial pressure of water will be less there. Since the
water vapor in the room will diffuse to maintain the same partial pressure,
more vapor will be drawn to the area near the waterfall, where it will
condense (because it exceeds the carrying capacity of cold air). The net
effect is that the room loses humidity. Pretty nifty.

Yep. If the water is above the dewpoint in the room, humidity
will rise. If it's colder than that dewpoint, room air moisture
condenses out in the chilled water stream, and humidity is lowered.

The mositure in the air doesn't know or care WHAT it's
condensing on, only the temperature and heat transfer capacity.

In fact, there are test chambers I've worked on that work
entirely on that principle. Instead of the air being blow across a
coil, it is blown through a saturation water spray chamber. By
controlling the water temperature, humidy is easily raised or lowered
on command.

Quote:

Michael


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


Joined: 25 Mar 2005
Posts: 2835

PostPosted: Sun May 21, 2006 3:10 am    Post subject: Re: Air Conditioner Question Reply with quote

Dear Herman Family:

"Herman Family" <ecalptsudwaseht.in.reverse@frontiernet.net>
wrote in message news:6DQbg.1591$oa1.1553@news02.roc.ny...
....
Quote:
I agree with the idea that the humidity will drop.
If the room is going to be cooled by the waterfall,
then the waterfall is at a lower temperature than
the room. It will enforce a relative humidity of
100 percent next to it, but the actuall grains of
water per cubic foot will be much lower, and hence the maximum
partial pressure of water
will be less there. Since the water vapor in the
room will diffuse to maintain the same partial
pressure, more vapor will be drawn to the area
near the waterfall, where it will condense
(because it exceeds the carrying capacity of
cold air). The net effect is that the room loses
humidity. Pretty nifty.

A little more fun than a "standard" room dehumidifier, which uses
both the evaporator (to condense the water from the air) and the
condensor (to warm the dried air back up) on the same air
stream...

David A. Smith
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Joseph S. Powell, III
science forum addict


Joined: 23 May 2005
Posts: 82

PostPosted: Sun May 21, 2006 2:36 pm    Post subject: Re: Air Conditioner Question Reply with quote

"Don A. Gilmore" <eromlignod@kc.rr.com> wrote in message
news:udNbg.2127$3q2.1403@tornado.rdc-kc.rr.com...
Quote:
.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.

Don
Kansas City

Try shoving the probe up your ass and see what it says.

Let us know!
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Harry Andreas
science forum beginner


Joined: 17 Aug 2005
Posts: 22

PostPosted: Mon May 22, 2006 8:12 pm    Post subject: Re: Air Conditioner Question Reply with 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:

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

--
Harry Andreas
Engineering raconteur
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