Can I Vent Window AC into Knee Wall???
Brad Murphy
years ago with central HVAC. Unfortunately the airflow to the
upstairs bedrooms is not adequate to cool 2 of the four rooms. This
is an A-Frame style home with cathedral ceilings. The rear bedroom
(the one I most want to cool down) has 3 foot knee-walls on two sides
and one outside wall with a sliding glass door. The room is approx.
14 x 10 and the center of the room is approx. 12 feet high.
I'd like to punch a hole in the kneewall and place an inexpensive AC
Window unit to help cool things off when we're there on the weekend.
Here are the obvious challenges:
1. Obviously the Knee-Wall is much like an attic area in terms of heat
from the roof. What issues might I encounter regarding this?
2. Condensation - I realize I'll have condensation issues to deal
with. Can this be handles by simply buliding a metal or plastic pan
that routes the water to the eave for removal from the knee wall area?
I've decided against an in-room unit because of the cost for something
that will get used so infrequently (probably 12 weekends a year).
Thanks for all suggestions / help.
brad
Sukie Taudry
Jmast42
>that will get used so infrequently (probably 12 weekends a year).
You may be better off either restricting the airflow to the rooms upstairs
you're not concerned about cooling, or adding booster fan(s) in the ducting to
assist with airflow.
An a/c unit in a kneewall will be more trouble than it's worth.
Another option is a portable a/c unit, rolls from room to room, costs about
$500.
Edwin Pawlowski
"Trent" <trent...@hotmail.com> wrote in message
> I'm keepin' mine right in the attic area. I'm just gonna put a large
> pan under it...in case any water does drip from the unit itself. But
> I think the water will evaporate easily and quickly from the unit. I
> don't think the extra pan will even be needed. And I have plenty of
> vents in the roof.
> Trent
My office at work is "landlocked" and the AC just vents into the building
via a closet that is not sealed (no roof).. While dripping is not a big
deal, there is still a lot of moisture that is going to be put in the attic
area. If you can ventilate this before it does any harm, the system will
work. If you can put a small attic fan in a the same time, you gain from
the heat removal from the attic area also.
The setup we have has been working for the past eight years with no
problems, you just have to get rid of the heat and moisture.
Ed
e...@snet.net
http://pages.cthome.net/edhome
Joseph Meehan
to pump heat uphill. The A/C will be very inefficient if it does not over
heat itself and will not produce anything close to it's rated cooling. In
addition heating the that area will allow much of that heat to come back
into your house.
--
Joseph E. Meehan
26 + 6 = 1 It's Irish Math
"Brad Murphy" <br...@digitalesp.com> wrote in message
news:5599f0a3.02060...@posting.google.com...
ma...@prob.com
<sligoj...@hotmail.com> wrote:
>26 + 6 = 1
Correct, IF you are working in a base 7 number system and doing modulo 35
arithmetic!
ma...@prob.com
<sligoj...@hotmail.com> wrote:
>26 + 6 = 1
Correct, IF you are working in a base 7 number system and doing modulo 35
arithmetic!
Edwin Pawlowski
"Joseph Meehan" <sligoj...@hotmail.com> wrote in message
...
> Bad idea. even if you get past the condensation problem, you are
trying
> to pump heat uphill.
Those guys that always said "heat rises" were wrong?
It is not the best situation, but the problems can be overcome. Yes, you
are moving the heat and moisture from one place to another, but once you
understand the physics of it, you can move those components outside and
have an even better situation.
Is your refrigerator vented outside? Why not?
Ed
e...@snet.net
http://pages.cthome.net/edhome
Dan O.
Edwin Pawlowski wrote in message ...
>
>Is your refrigerator vented outside? Why not?
Because it is only transferring a maximum of 1300 BTUs of heat when running
which the house air can easily absorb as opposed to a **minimum** of 5,000 BTUs
for the very smallest air conditioner you can buy. And that is PER HOUR!
Dan O.
-
Appliance411.com
http://ng.Appliance411.com/?ref411=air+conditioner
=Ð~~~~~~
Dan O.
Trent wrote
>
>The heat on the exterior side shouldn't make any difference. If
>anything, it might help to evaporate the water. Even if you'd put the
>a/c in a window, you'd still have the same environment problems.
If you realize the way an air conditioner works is by moving heat from inside to
room to outside it will be easier to understand the problem with this.
If the space you're venting the A/C into isn't itself vented, the hot air is
just going to build up in that area. The hotter it gets, the harder the A/C will
have to work to do the same job eventually totally unable to do much at all. If
roof isn't insulated that will also increase that area's temperature as well,
when the sun is out.
I would say that if you can **well** ventilate that area (like with an
additional fan) and make an acceptable drain for the condensate, you'll probably
be able to get satisfactory results. If you do not make allowances for the heat
build up in that area, I do not think it would work well for long and could lead
to premature component(s) failure.
JMO
HvacTech2
Hi Edwin, hope you are having a nice day
On 03-Jun-02 At About 18:01:38, Edwin Pawlowski wrote to All
Subject: Re: Can I Vent Window AC into Knee Wall???
EP> From: "Edwin Pawlowski" <e...@snet.net>
EP> Is your refrigerator vented outside? Why not? Ed e...@snet.net
Because it is only a very small amount of heat verses a window a/c. venting
an A/C in an attic is asking for trouble. there is just too much heat and the
unit will run too hot and have a shorter life span then a properly vented
unit. not to mention humid days and where to get rid of the water. the best
solution is a mini ductless split or what is called a twin pak unit. I am not
sure if they make twin paks anymore though.
-=> HvacTech2 <=-
.. If I throw a cat out of the car window, is it kitty litter?
___ TagDude 0.92á+[DM]
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
spam protection measure, Please remove the 33 to send e-mail
BACcontra91
one wall of the foreman's office with a small AC I can tell you from
experience. His office was nice and cold, my cubicle was at least 10° hotter
than the rest of the warehouse. Plus I would drain over 3 gallons a day of
condensate of the back of his unit if it was humid outside. Any heat removed
on the front end must GO somewhere. Heat is energy and the physics are that
energy never just goes away. The heat removed from the front of the unit
would dump out the back of the unit and, other than the a 5' area in front
of the AC, room would average out to one temperature.
The fridge argument doesn't hold because, as previously mentioned, the BTU's
comparison isn't even close. If you check on any older fridge with exposed
coils, (newer ones have sealed backs) the 3-4" behind the fridge IS hotter
than the rest of the room.
> I've never tried it, but I'd think that you could cool a room even if
> the air conditioner was sitting on a chair in the room.
> Trent
!
HvacTech2
Hi Trent, hope you are having a nice day
On 04-Jun-02 At About 08:19:06, Trent wrote to All
Subject: Re: Can I Vent Window AC into Knee Wall???
T> From: Trent <trent...@hotmail.com>
T> On Mon, 3 Jun 2002 21:07:44 -0400, "Dan O."
T> <forum@_NO-JUNK_appliance411.com> wrote:
T> > The hotter it gets, the harder the A/C will >have to work to do
T> the same job
T> I understand that. I concede that an air conditioner won't have to
T> work as hard if the OUTSIDE air is 35? vs. 135?.
T> But what does this have to do with a particular conditioner on a
T> particular day? You're not gonna INCREASE the temperature on the
T> outside of the knee wall because of the air conditioner...except for
T> the minor heat generated by the motor itself.
Not quite correct Trent. You are generating heat from the motor and
compressor but where do you think the heat you are removing from the room
goes? Yep, right to the attic in your case. this will overheat the attic
space.
>> eventually totally unable to do much at all. If roof isn't insulated
T> > that will also increase that area's
T> temperature as well, >when the sun is out.
T> But that's a different issue. That has nothing to do with what we're
T> talking about. You'd have that same issue if the conditioner was
T> in a window on a sunny day vs. a cloudy day.
Again not right. in the attic space it will build up the heat unless you use
a fan to ventilate it. whereas outdoors you are not going to overheat. the
space. ( outdoors )
T> > I would say that if you can **well** ventilate that area (like
T> with an > additional fan) and make an acceptable drain for the
T> condensate, you'll probabl >be able to get satisfactory results. If
T> you do not make allowances for the hea >build up in that area, I do
T> not think it would work well for long and could lea >to premature
T> component(s) failure.
T> Unless I'm really missing something, I disagree. You CAN'T raise the
T> temperature on the other side of the air conditioner...except for
T> the heat generated by the motor. And I even doubt that the motor
T> temperature would be higher than the air temperature in most attics.
T> So how are you gonna RAISE the air temperature?
You are missing something Trent. you will definitely raise the attic space
temp as you are adding the heat from the space you are cooling plus the
compressor and fan motor heat generated.
T> As Ed mentioned, how do refrigerators work?...and walk-in freezers?
T> Just consider the cooled area the inside of the freezer...the air
T> conditioner as the outside coils.
Basically the same. I think you need to understand that the evaporator
absorbs the heat and moves it to the condenser where it is rejected to the
outside air.
T> I've never tried it, but I'd think that you could cool a room even if
T> the air conditioner was sitting on a chair in the room.
Nope. all you would do is reintroduce the heat you removed plus you would
actually overheat the space due to the added compressor and fan motor heat
-=> HvacTech2 <=-
.. "Curiosity killed the cat, but for a while I was a suspect."- s.w.
Dan O.
Trent wrote in message ...
>
>I would expect that my attic...and EVERY
>attic...is vented...to SOME extent. In my particular case, Dan, I
>have about a dozen roof vents.
The *minimum* amount of air a window type of air conditioner moves is about 170
cfm. Unless your attic venting removes that much air (very doubtful for static
vents no matter how many you have), you're going to get a build up of hot air.
>>The hotter it gets, the harder the A/C will
>>have to work to do the same job
>
>I understand that. I concede that an air conditioner won't have to
>work as hard if the OUTSIDE air is 35? vs. 135?.
>
>But what does this have to do with a particular conditioner on a
>particular day? You're not gonna INCREASE the temperature on the
>outside of the knee wall because of the air conditioner...except for
>the minor heat generated by the motor itself.
As already stated by someone else, not only the very minimal heat generated by
the fan motor and a bit more generated by the compressor, but ALL the heat
removed from the room air. Where do you think that is going to go?
>> eventually totally unable to do much at all. If
>>roof isn't insulated that will also increase that area's temperature as well,
>>when the sun is out.
>
>But that's a different issue. That has nothing to do with what we're
>talking about. You'd have that same issue if the conditioner was in a
>window on a sunny day vs. a cloudy day.
It matters very little whether it is sunny or cloudy but how much air there is
to absorb the heat from the condenser of the air conditioner. Even if the
outside air was only 1 degree cooler than the temperature of the condenser,
there is enough air outdoors to absorb all the heat you're trying to remove. The
amount of air in most attics is simply insufficient for such a purpose (for long
anyway).
>>I would say that if you can **well** ventilate that area (like with an
>>additional fan) and make an acceptable drain for the condensate, you'll
probably
>>be able to get satisfactory results. If you do not make allowances for the
heat
>>build up in that area, I do not think it would work well for long and could
lead
>>to premature component(s) failure.
>
>Unless I'm really missing something, I disagree. You CAN'T raise the
>temperature on the other side of the air conditioner...except for the
>heat generated by the motor. And I even doubt that the motor
>temperature would be higher than the air temperature in most attics.
>So how are you gonna RAISE the air temperature?
See the reply above.
>As Ed mentioned, how do refrigerators work?...and walk-in freezers?
>Just consider the cooled area the inside of the freezer...the air
>conditioner as the outside coils.
I don't know what you mean by that.
*IF* a walk-in freezer had its condenser inside the store, the store would have
to have an air conditioner to remove the heat from the room air. Really large
walk-in coolers and freezers have their condensers outdoors just like a central
air conditioner.
>I've never tried it, but I'd think that you could cool a room even if
>the air conditioner was sitting on a chair in the room.
From my previous post:
>>If you realize the way an air conditioner works is by moving heat from inside
to
>>room to outside it will be easier to understand the problem with this.
So keeping that in mind, you move the heat from the front of the air conditioner
to the rear of the air conditioner so the room air can adsorb that heat again.
Then you add the heat generated by the motor and compressor with a net effect of
increasing the room temperature.
Edwin Pawlowski
"Dan O." <forum@_NO-JUNK_appliance411.com> wrote in message
> >As Ed mentioned, how do refrigerators work?...and walk-in freezers?
> >Just consider the cooled area the inside of the freezer...the air
> >conditioner as the outside coils.
>
> I don't know what you mean by that.
>
> *IF* a walk-in freezer had its condenser inside the store, the store would
have
> to have an air conditioner to remove the heat from the room air. Really
large
> walk-in coolers and freezers have their condensers outdoors just like a
central
> air conditioner.
My reference to a nay-sayer that it was not possible to do this setup. It
is a matter of moving the heat (and moisture). Venting to an attic is not
the best method, but with a little planning it can be done. A refrigerator
removes heat from inside the cabinet and moves it to the inside of the
kitchen. Now you have one area colder and another warmer, but they average
out the same (aside from heat added by the motor) Same with venting to the
attic. Additional venting to the attic will possibly result into a net
comfort gain as even more heat will be removed than by doing nothing.
Would I do this? If it was the only method of cooling my sleeping room,
yes. I would, however, take proper precautions to add extra venting to the
attic space and to provide a drip pan under the AC for condensate that does
not evaporate. A room AC sitting in a window on the sunny side of the house
is not the best setup either, but millions of them work like that. Avoid the
sun and excess heat from the attic and the appliance will operate more
efficiently and last longer.
Ed
e...@snet.net
http://pages.cthome.net/edhome
Joseph Meehan
"Edwin Pawlowski" <e...@snet.net> wrote in message
news:%hcL8.21341$b34.237...@newssvr10.news.prodigy.com...
>
...
> Would I do this? If it was the only method of cooling my sleeping room,
> yes. I would, however, take proper precautions to add extra venting to
the
> attic space and to provide a drip pan under the AC for condensate that
does
> not evaporate. A room AC sitting in a window on the sunny side of the
house
> is not the best setup either, but millions of them work like that. Avoid
the
> sun and excess heat from the attic and the appliance will operate more
> efficiently and last longer.
> Ed
> e...@snet.net
> http://pages.cthome.net/edhome
>
>
>
the transfer material and it is its temperature that really counts.
--
Joseph E. Meehan
26 + 6 = 1 It's Irish Math
BACcontra91
knee wall will not get any hotter than say 150° +/- the compressor which
probably does run a bit higher tahn the ambient would be. As one poster
mentioned, passive roof vents probably would not allow enough airflow to
remove the air from the attic. This would create two problems. First
positive pressure behind the knee wall which could lead to warm air being
forced back into the room you are cooling and overtaxing the AC. Second,
MOIST air behing the knee wall. Attics usually run warm but DRY. Perhaps, as
one poster mentioned the condensate would evaporate fast enough to not need
a drip pan, unless you get that moist air out of your attic, every night
when the roof cools all the moisture will re-condense out of the air on the
INSIDE of your roof sheathing. Drip. Drip. As far as I know, that is still
not reccomended by the pro's in any field.
"Trent" <trent...@hotmail.com> wrote in message
news:l28sfu0bppj33vm45...@4ax.com...
> On Tue, 4 Jun 2002 18:56:25 -0400, "Dan O."
> <forum@_NO-JUNK_appliance411.com> wrote:
>
> >
> >Trent wrote in message ...
> >>
> >>I would expect that my attic...and EVERY
> >>attic...is vented...to SOME extent. In my particular case, Dan, I
> >>have about a dozen roof vents.
> >
> >The *minimum* amount of air a window type of air conditioner moves is
about 170
> >cfm. Unless your attic venting removes that much air (very doubtful for
static
> >vents no matter how many you have), you're going to get a build up of hot
air.
>
> What do you mean by 'build up', Dan. Both sides have started out the
> same...let's say 150?. Do you mean that the outside of the wall will
> get HOTTER than 150??...that the air expelled by the a/c is HOTTER
> than 150?? Again, I'm aware of the minor heat generated by the motor,
> etc.
>
> >>I understand that. I concede that an air conditioner won't have to
> >>work as hard if the OUTSIDE air is 35? vs. 135?.
> >>
> >>But what does this have to do with a particular conditioner on a
> >>particular day? You're not gonna INCREASE the temperature on the
> >>outside of the knee wall because of the air conditioner...except for
> >>the minor heat generated by the motor itself.
> >
> >As already stated by someone else, not only the very minimal heat
generated by
> >the fan motor and a bit more generated by the compressor, but ALL the
heat
> >removed from the room air. Where do you think that is going to go?
>
> Anywhere it wants! lol But seriously, both sides start out at 150?.
> The heat removed from the room CAN'T be any hotter than 150?...during
> ANY cycle of the conversion. So where's the heat build up coming
> from?
>
> >It matters very little whether it is sunny or cloudy but how much air
there is
> >to absorb the heat from the condenser of the air conditioner. Even if the
> >outside air was only 1 degree cooler than the temperature of the
condenser,
> >there is enough air outdoors to absorb all the heat you're trying to
remove. The
> >amount of air in most attics is simply insufficient for such a purpose
(for long
> >anyway).
>
> That MAY be a different issue, Dan. I have no idea of the amount of
> heat generated by the compressor itself. But, in relation to the
> entire volume of an average attic, its gotta be a minimal
> consideration. The outside area of the compressor would be a very
> small heating utensil in relation to the volume of the attic. Would
> the compressor heat to more than 150? or so?...which would be the
> ambient air temperature on average in many attics.
>
> >>As Ed mentioned, how do refrigerators work?...and walk-in freezers?
> >>Just consider the cooled area the inside of the freezer...the air
> >>conditioner as the outside coils.
> >
> >I don't know what you mean by that.
> >
> >*IF* a walk-in freezer had its condenser inside the store, the store
would have
> >to have an air conditioner to remove the heat from the room air. Really
large
> >walk-in coolers and freezers have their condensers outdoors just like a
central
> >air conditioner.
>
> I believe that many don't.
>
> >>I've never tried it, but I'd think that you could cool a room even if
> >>the air conditioner was sitting on a chair in the room.
> >
> >From my previous post:
> >
> >>>If you realize the way an air conditioner works is by moving heat from
inside
> >to
> >>>room to outside it will be easier to understand the problem with this.
> >
> >So keeping that in mind, you move the heat from the front of the air
conditioner
> >to the rear of the air conditioner so the room air can adsorb that heat
again.
>
> >Then you add the heat generated by the motor and compressor with a net
effect of
> >increasing the room temperature.
>
> Taking all that into account, then, I'd think it could be done if you
> have the proper size a/c...thereby minimizing running time.
>
> Theoretically, COULD it be done? Couldn't an a/c just keep recycling
> the air within the room?...until the optimum temperature is achieved?
>
> For the sake of argument, lets make it a 500,000 btu window model!!
> lol
>
>
> Have a nice week...
>
> Trent
>
> We don't rent pigs!
John Cochran
Trent <trent...@hotmail.com> wrote:
>On Tue, 04 Jun 2002 20:37:55 GMT, "HvacTech2" <dmurp...@snet.net>
>wrote:
>
>> T> But what does this have to do with a particular conditioner on a
>> T> particular day? You're not gonna INCREASE the temperature on the
>> T> outside of the knee wall because of the air conditioner...except for
>> T> the minor heat generated by the motor itself.
>>
>>Not quite correct Trent. You are generating heat from the motor and
>>compressor but where do you think the heat you are removing from the room
>>goes? Yep, right to the attic in your case. this will overheat the attic
>>space.
>
>wall start out at 160?, the inside will soon be less than that. The
>outside will never be more than that...again, except for the little
>bit of heat generated by the electrical/mechanical parts.
>
[major snippage....]
Trent, an air conditioner *moves* heat from one side to another. In the
process it also generates a little heat from the motor and compressor. To
show you, here is a *very* simplified description of how an air conditioner
works.
1st fact. When you compress a gas it gets hotter.
2nd fact. When you expand a gas it gets cooler.
3nd fact. Heat travels from hot to cold.
4rd fact. Boiling a liquid requires heat being added to the liquid.
1. Starting with liquid freon you let it assorb heat from the air in an
heat exchanger (it looks something like a car radiator). Doing this will
boil the freon and cool the air.
2. You now take the gaseous freon and compress it. This raises the temperature
of the freon gas. You now pass the hot freon into another heat exchanger
and pass air over it. This will cause the air to heat up and the freon
to cool down. This can only happen if the air temperature is less than
the temperature of the hot freon.
3. You now take the high pressure (and warm) freon and let it expand. This
will cause the temperature of the freon to drop and liquify.
Now repeat from step 1.
Note: The above process in an ideal world will not change the total amount
of heat available. But due to inefficacies, the motor and compressor will
add some heat to the process. Things to note:
1. The "hot" heat exchanger *MUST* be hotter than the air it's in. If
this isn't the case, it will not work. The greater the temperature
difference, the better it works. But if the air isn't cooler than
the heat exchanger, it won't work.
2. The "cold" heat exchanger *MUST* be cooler then the air it's in. If
this isn't the case, then it also won't work. You'll have the compressor
attempting to compress liquid freon and this is bad news for the
compressor.
Now with this theory in mind, take a look again at your posts on this
subject and rethink your position.
--
The email address is valid and will reach me.
The userid is being used as an anti-spam measure.
Dan O.
BACcontra91 wrote in message ...
>
>This would create two problems. First
>positive pressure behind the knee wall which could lead to warm air being
>forced back into the room you are cooling and overtaxing the AC.
There should be no pressure increase as the condenser would such in the attic
air and expel that same air back into the attic resulting in a balance.
> Second, MOIST air behing the knee wall.
This could be a problem as most window/wall air conditioners throw the
condensate recovered from the room humidity onto the condenser. This moisture
evaporates and aids in heat removal from the condenser.
If you can find a air conditioner model with does *not* do this and are able to
properly drain all the condensate away, moisture should not be a problem in the
attic.
Edwin Pawlowski
> >>the air conditioner was sitting on a chair in the room.
> have the proper size a/c...thereby minimizing running time.
>
> Theoretically, COULD it be done? Couldn't an a/c just keep recycling
> the air within the room?...until the optimum temperature is achieved?
>
> For the sake of argument, lets make it a 500,000 btu window model!!
> lol
Won't work. It does not eliminate heat,just moves it to another place.
Since that place is in the same room, net effect will be nil, but heat from
the motor will be added. While you may "feel" cooler sitting in front of the
machine with cooler air blowing on you, the rest of the room will feel
hotter as the warm air blows that way.
Ed
e...@snet.net
http://pages.cthome.net/edhome
whiz444
experience, I should be able to forgo any air conditioning knowledge and
spout unfounded opinions to confuse people and myself.
I am going to cool my attic by sitting a air conditioner on a chair and let
'er rip. Can't wait for those cool August attic nights!
"Sam" <notmyrea...@notswbell.net> wrote in message
news:Xns92248447CA280...@151.164.30.48...
> Trent <trent...@hotmail.com> wrote:
>
> > Unless I'm really missing something, I disagree. You CAN'T raise
> > the temperature on the other side of the air conditioner...except
> > for the heat generated by the motor.
>
> You obviously don't understand air conditioning. The heat has to go
> *somewhere*. You're taking the heat from the room being cooled and
> pumping it out the back of the A/C. This heat *will* heat up the
> kneewall space. Some of this heat will radiate back into the room
> through the wall. Also, if the kneewall air becomes warmer than the
> air moving across the condenser coil, the A/C will cease to function.
> However, you'll probably kill the compressor before this happens.
>
>
> > I've never tried it, but I'd think that you could cool a room even
> > if the air conditioner was sitting on a chair in the room.
>
> No, you obviously haven't tried it. Sitting an A/C in the middle of a
> room would make it function like a dehumidifier. It would not cool the
> room and would likely heat the room slightly, from the power
> consumption of the unit.
>
>
>
> --
> Sam
> Undo every "not" in my email address to reply.
> Outlook users: Don't add me to your address book.
HvacTech2
Hi John, hope you are having a nice day
On 05-Jun-02 At About 02:03:42, John Cochran wrote to All
Subject: Re: Can I Vent Window AC into Knee Wall???
JC> From: ab...@fiawol.org (John Cochran)
JC> Now with this theory in mind, take a look again at your posts on this
JC> subject and rethink your position. --The email address is valid
JC> and will reach me. The userid is being used as an anti-spam measure.
I really can't understand why But he can't seem to grasp the concept.
-=> HvacTech2 <=-
.. "Can I take an ax to school tomorrow for, um, Show and Tell?"
HvacTech2
Hi Trent, hope you are having a nice day
On 05-Jun-02 At About 08:27:09, Trent wrote to All
Subject: Re: Can I Vent Window AC into Knee Wall???
T> From: Trent <trent...@hotmail.com>
T> On Tue, 04 Jun 2002 20:37:55 GMT, "HvacTech2" <dmurp...@snet.net>
T> wrote:
T> Is the heat transfer a 1:1 conversion? I didn't think it was.
I don't know how else to make you understand Trent. if you remove heat it
has to go somewhere else. in the case of an a/c it goes out to the condenser
where it is rejected to the outside air. in the case of the attic it would
just build up in the space and overheat it unless you had some really hefty
exhaust fans helping draw it out of the attic.
-=> HvacTech2 <=-
.. A foot is a device for finding furniture in the dark.
Pamini
says...
say about that. Now a days they all have 800 No's. you can call, and web pages
you can go to and email them etc.
How about an exhaust fan
http://www.sundancesupply.com/ModelGfans.html (i am getting this one)
http://ablegroup.net/html/27.html
http://www.trianglefans.com/gpx.htm
http://www.senet.com.au/~cliveb/coolmax.htm this is an inside cooler.
pamini
Edwin Pawlowski
"Pamini" <nos...@newsranger.com> wrote in message
> It sounds as a fire hazard to me. Plus what does the manufacturer of the
product
> say about that.
What would make this more of a hazard than any of the attic and whole house
fans used in the attic area?
I'm sure the manufacturer will say it is made for window installation. That
does not meat it will not work. As stated earlier, my office is landlocked,
but yet cooled with a window AC mounted in the wall.
Ed
e...@snet.net
http://pages.cthome.net/edhome
glenn
cbhvac
> On Tue, 4 Jun 2002 18:56:25 -0400, "Dan O."
> <forum@_NO-JUNK_appliance411.com> wrote:
>
> >
> >>
> >>I would expect that my attic...and EVERY
> >>attic...is vented...to SOME extent. In my particular case, Dan, I
> >>have about a dozen roof vents.
So?
> >
> >The *minimum* amount of air a window type of air conditioner moves is
about 170
> >cfm. Unless your attic venting removes that much air (very doubtful for
static
> >vents no matter how many you have), you're going to get a build up of hot
air.
Correct..
>
> What do you mean by 'build up', Dan. Both sides have started out the
> same...let's say 150?. Do you mean that the outside of the wall will
> get HOTTER than 150??...that the air expelled by the a/c is HOTTER
> than 150?? Again, I'm aware of the minor heat generated by the motor,
> etc.
Go look at a temp/pressure chart for R22, figure in your 150F ambients,
then, figure in your high side pressures in a theoretical 150F ambient, with
an intake air temp of 150F...
Can you say discharge temps of a hell of a lot more?
>
> >>I understand that. I concede that an air conditioner won't have to
> >>work as hard if the OUTSIDE air is 35? vs. 135?.
Newsflash-R22, pressures have temps, temps have pressures,
Thats the explanation for that..altho...only an idiot would try to run a
window unit at 35F...
> >>
> >>But what does this have to do with a particular conditioner on a
> >>particular day? You're not gonna INCREASE the temperature on the
> >>outside of the knee wall because of the air conditioner...except for
> >>the minor heat generated by the motor itself.
You just dont get the principles...again...you have to take into
consideration of the head pressures...head pressure=temp.
> >
> >As already stated by someone else, not only the very minimal heat
generated by
> >the fan motor and a bit more generated by the compressor, but ALL the
heat
> >removed from the room air. Where do you think that is going to go?
>
> Anywhere it wants! lol But seriously, both sides start out at 150?.
> The heat removed from the room CAN'T be any hotter than 150?...during
> ANY cycle of the conversion. So where's the heat build up coming
> from?
Wrong..it can get hotter than it was....ahh..confusing as hell aint it?
>
> >It matters very little whether it is sunny or cloudy but how much air
there is
> >to absorb the heat from the condenser of the air conditioner. Even if the
> >outside air was only 1 degree cooler than the temperature of the
condenser,
> >there is enough air outdoors to absorb all the heat you're trying to
remove. The
> >amount of air in most attics is simply insufficient for such a purpose
(for long
> >anyway).
>
> That MAY be a different issue, Dan. I have no idea of the amount of
> heat generated by the compressor itself. But, in relation to the
> entire volume of an average attic, its gotta be a minimal
> consideration. The outside area of the compressor would be a very
> small heating utensil in relation to the volume of the attic. Would
> the compressor heat to more than 150? or so?...which would be the
> ambient air temperature on average in many attics.
Ask the burn on my arm...150F is low....working on a Copland Semi yesterday
that kept hitting almost 450PSI on the high side...go look at the temp of
that...
>
> >>As Ed mentioned, how do refrigerators work?...and walk-in freezers?
> >>Just consider the cooled area the inside of the freezer...the air
> >>conditioner as the outside coils.
Ok..they work the same way...at lower inside temps, meaning, you have a coil
that is say...10F once its been running 24 hours...VS a coil that is
say..90F when first started...guess what? The amount of heat given off by
the condensor during the first 24 hours is pretty great..once you lower the
temp of the case, the case has less heat, and it does not have to run as
long to remove the same amount of heat, since there is little latent heat in
the box, and the difference in say...15F and 10F when you open the box is
much less than 90F and 10F...
> >
> >I don't know what you mean by that.
> >
> >*IF* a walk-in freezer had its condenser inside the store, the store
would have
> >to have an air conditioner to remove the heat from the room air. Really
large
> >walk-in coolers and freezers have their condensers outdoors just like a
central
> >air conditioner.
>
> I believe that many don't.
All but one that I work on do. Want pics? They dont even have to be
large....Mantiwoc 500lb ice machines have a condensor mounted on the roof,
if its air cooled...
>
> >>I've never tried it, but I'd think that you could cool a room even if
> >>the air conditioner was sitting on a chair in the room.
nope
One side fighting against the other..where do you really think all the heat
being removed goes??
AC is simple...its not rocket science...its simple the TRANSFER of heat from
one place to another....where is the other part on a window unit??
> >
> >From my previous post:
> >
> >>>If you realize the way an air conditioner works is by moving heat from
inside
> >to
> >>>room to outside it will be easier to understand the problem with this.
> >
> >So keeping that in mind, you move the heat from the front of the air
conditioner
> >to the rear of the air conditioner so the room air can adsorb that heat
again.
And raise that head temp.....
>
> >Then you add the heat generated by the motor and compressor with a net
effect of
> >increasing the room temperature.
>
> Taking all that into account, then, I'd think it could be done if you
> have the proper size a/c...thereby minimizing running time.
What?? LArger AC meanings more heat transfer? LOL
>
> Theoretically, COULD it be done? Couldn't an a/c just keep recycling
> the air within the room?...until the optimum temperature is achieved?
No
>
> For the sake of argument, lets make it a 500,000 btu window model!!
a 4167 ton unit...Ok...so..when do you want to call the fire department..LOL
Sorry..but this thread is taking the cake...
I thought arguements about ICB's and burned resistors was funny
Capt. Fixxit
> On Wed, 5 Jun 2002 12:03:42 -0400, ab...@fiawol.org (John Cochran)
> wrote:
>
> As an opener, John, I have very little general knowledge of air
> conditioning principles. And I have no practical experience
> whatsoever.
You said a mouthful right there, Trent.
But there you go arguing with the people that DO KNOW.
Are a clone of Muff? or are you a d(dumb)bird clone, huh, Trent?
Capt. Fixxit®
*** Banned Newsgroups ***
No-Limits, Privacy and Anonymous!!!
Try us for FREE at www.goliathnews.com
Capt. Fixxit
"glenn" <geor...@cei.net> wrote in message
news:83FL8.4$sn.4...@typhoon.cei.net...
> What a watse of a thread?
>
And at least half of the thread was from TRENTch mouth who actually knows
LESS than MUFF and d(dumb)bird.
Rotcetedeloha
clone?
Rotcetedeloha
> As an opener, John, I have very little general knowledge of air
>> conditioning principles. And I have no practical experience
>> whatsoever.
Capt. Fixxit ? Now you think you're a Bob Villa clone. Bob was never that good,
but you can't even lick his soles.
Brad Murphy
mini-split ($1,500 installed) it seems to me that if I can locate an
attic exhaust fan directly over the area the AC unit will be placed
and additionally, provide adequate removal of condenstation then this
will probably provide me with adequate results at a reasonable price.
Remember, I'm only looking to run this unit 10-12 weekends each year.
The rest of the time the unit will remain off.
Thanks!
brad
"Edwin Pawlowski" <e...@snet.net> wrote in message news:<EmxL8.21521$DU2.243...@newssvr10.news.prodigy.com>...
cbhvac
"Trent" <trent...@hotmail.com> wrote in message
news:1mftfusiikudeltsa...@4ax.com...
> On Wed, 5 Jun 2002 12:03:42 -0400, ab...@fiawol.org (John Cochran)
>
> As an opener, John, I have very little general knowledge of air
> conditioning principles. And I have no practical experience
> like I don't understand...its because I DON'T! Thanks to you and
> everyone else for the patience.
You are tame compared to some..
>
> Here's some more comments...and questions...for you and anyone else...
>
> >Trent, an air conditioner *moves* heat from one side to another.
>
> I understand that principle. But it doesn't actually move AIR, does
> it? Everyone has commented about the air being forced to the other
> side of the knee wall. That doesn't really HAPPEN, does it?
AC is ALL about the transfer of heat, and the movement of air...
>
> Its my understanding that the HEAT is being exchanged...thru the
> coils. The fans...on each side of the a/c...operate within their own
> separate environment...and don't infringe into either's environment.
> They each have their own separate purpose.
Correct, ,unless you have them in the same space....and an AC unit sitting
on a stool in a room is having both in the same space..
>
> I DO understand that there IS an exhaust setting on most a/c's,
> however.
>
If you want to call a 1x 2 inch hole an exhaust...
Its about worthless..
> >In the
> >process it also generates a little heat from the motor and compressor.
>
> That part I understand...and concede.
What part of the equasion did you leave out?? :)
>
> >To
> >show you, here is a *very* simplified description of how an air
conditioner
> >works.
> >
> >1st fact. When you compress a gas it gets hotter.
> >2nd fact. When you expand a gas it gets cooler.
> >3nd fact. Heat travels from hot to cold.
> >4rd fact. Boiling a liquid requires heat being added to the liquid.
> >
> >1. Starting with liquid freon you let it assorb heat from the air in an
> > heat exchanger (it looks something like a car radiator). Doing this
will
> > boil the freon and cool the air.
>
> If I've got it right so far, air is being 'conditioned' on the inside
> of the knee wall. The heat...not the air...is being transferred to
> the back side of the a/c.
Right, and there is a fan back there too..
>
> >2. You now take the gaseous freon and compress it. This raises the
temperature
> > of the freon gas. You now pass the hot freon into another heat
exchanger
> > and pass air over it. This will cause the air to heat up and the freon
> > to cool down. This can only happen if the air temperature is less than
> > the temperature of the hot freon.
>
> Examples of temperatures, John? I'm guessing we're talking EXTREME
> temperatures here...thousands of degrees?
Not in a POS window unit...
>
> >3. You now take the high pressure (and warm) freon and let it expand.
This
> > will cause the temperature of the freon to drop and liquify.
> >
> > Now repeat from step 1.
>
> >Note: The above process in an ideal world will not change the total
amount
> >of heat available. But due to inefficacies, the motor and compressor will
> >add some heat to the process.
>
> Which would be on the attic side of the wall...correct?
And what happens when you add more heat to the condensor side? Heat transfer
to the air is reduced, flashgas becomes an issue....all kinds of fun things
can start..
>
> >Things to note:
> >
> > 1. The "hot" heat exchanger *MUST* be hotter than the air it's in. If
> > this isn't the case, it will not work. The greater the temperature
> > difference, the better it works. But if the air isn't cooler than
> > the heat exchanger, it won't work.
>
> > 2. The "cold" heat exchanger *MUST* be cooler then the air it's in. If
> > this isn't the case, then it also won't work. You'll have the
compressor
> > attempting to compress liquid freon and this is bad news for the
> > compressor.
> >
>
> Put this in terms of...the front and back of the a/c, wud ya.
Condensor=rear coil on window unit
Evap=coil in the front that you can see when its mounted in a window..
Condensor=hot
Evap=cold
Unless its a heat pump in heat mode..
>
> >Now with this theory in mind, take a look again at your posts on this
> >subject and rethink your position.
>
> I think, after the next go-round from everybody, I'm gonna move on!
Wanna know the big one you left out?
Ok...here it is..
For examples, its gonna be simple
BTU gain from roof is 100 BTU an hour
BTU rating of unit is 100BTU an hour....
Actual BTUs released by unit in cooling from heat absorbed from all aspects
of operation=120BTU
This is a very simple, and exaggerated example...but, in reality, you havent
cooled anything..
> lol
>
> Thanks for everyone's patience.
>
>
> Have a nice week...
>
> Trent
>
> Cat...the OTHER white meat!
cbhvac
Goodman, or used...or a VERY small Mitsu...
The COST of the inside unit itself on a 2 ton Mitsubishi is that almost..
"Brad Murphy" <br...@digitalesp.com> wrote in message
news:5599f0a3.02060...@posting.google.com...
Dan O.
Trent wrote in
>
> I have very little general knowledge of air
>conditioning principles. And I have no practical experience
>whatsoever. So if I make some stupid statements...and if it seems
>like I don't understand...its because I DON'T! Thanks to you and
>everyone else for the patience.
>
>
>
>it? Everyone has commented about the air being forced to the other
>side of the knee wall. That doesn't really HAPPEN, does it?
Only 1 person commented about something like that, concerned about increased air
pressure in the attic. I replied that that is *not* the case.
The condenser (hot part) sucks in the outdoor air and expels the same outdoor
air again (only hotter). The evaporator (cooling) coil sucks in room air and
expels the same room air but with less heat (aka cooler).
>Its my understanding that the HEAT is being exchanged...thru the
>coils. The fans...on each side of the a/c...operate within their own
>separate environment...and don't infringe into either's environment.
>They each have their own separate purpose.
>>But due to inefficacies, the motor and compressor will
>>add some heat to the process.
>
>Which would be on the attic side of the wall...correct?
Yes, except in the case that someone mentioned of running and air conditioner in
the middle of a room. Which I believe is when that point came up. I really think
it would contribute very little to the increased attic temperature (in relation
to what the refrigeration part of the air conditioner would do by itself).
>>Things to note:
>>
>> 1. The "hot" heat exchanger *MUST* be hotter than the air it's in. If
>> this isn't the case, it will not work. The greater the temperature
>> difference, the better it works. But if the air isn't cooler than
>> the heat exchanger, it won't work.
>
>> 2. The "cold" heat exchanger *MUST* be cooler then the air it's in. If
>> this isn't the case, then it also won't work. You'll have the compressor
>> attempting to compress liquid freon and this is bad news for the
>> compressor.
>>
>
>Put this in terms of...the front and back of the a/c, wud ya.
The condenser (hot side) has to be hotter that the surrounding air to be able to
'off load' the heat the refrigerant traveling through it is carrying. The
evaporator (cooling) coil will have to feel colder than the room air in order to
absorb (aka remove) heat from that air.
I hope it helps.
Dan O.
>> >Trent wrote in message ...
>> >>
>> >>I would expect that my attic...and EVERY
>> >>attic...is vented...to SOME extent. In my particular case, Dan, I
>> >>have about a dozen roof vents.
If an air conditioner is dumping a minimum of 170 cfm of *hot* air into the
attic space, that is how much air your vents will need to remove to keep a
temperature balance. If your roof vents expels **any** less air than the air
conditioner produces, the net effect is an increase in temperature which will
eventually build up until the A/C can no longer remove heat from the refrigerant
resulting in the A/C stopping functioning.
>> What do you mean by 'build up', Dan. Both sides have started out the
>> same...let's say 150?. Do you mean that the outside of the wall will
>> get HOTTER than 150??...that the air expelled by the a/c is HOTTER
>> than 150??
If the surrounding air (in the attic in your case) is 150 degrees, the condenser
will have to be at least 170 degrees (actually probably higher) to release heat
into that air. Now the 170 air is in the attic and the air conditioner's
condenser will need to be 190 degrees to release heat. Now 190 degree air is in
the attic and the condenser needs to be 210 degrees to release the refrigerant's
heat. etc. etc. etc.
Unless your attic ventilation can exhaust **all** the hot air produced by the
air conditioner, that is what will happen until either the air conditioner just
can't remove heat any more or the compressor fails due to the extreme conditions
it made to work in. A bit exaggerated perhaps depending on the actual space
available to store the hot air (ie. the size of the attic)
>> >As already stated by someone else, not only the very minimal heat
>> >generated by
>> >the fan motor and a bit more generated by the compressor, but ALL the
>> >heat removed from the room air. Where do you think that is going to go?
>> Anywhere it wants! lol But seriously, both sides start out at 150?.
>> The heat removed from the room CAN'T be any hotter than 150?...during
>> ANY cycle of the conversion. So where's the heat build up coming
>> from?
If both inside and outside air temperatures were 150 and you wanted an air
conditioner to cool down to 70, the outside air would have to absorb the
difference.
A *very* unrealistic example if the 80 degrees you removed from inside is now
outside (150+80=230). The inside is now nice and cool at 70 degrees while now
the outside air is 230 degrees. You need to vent that 230 degree air out of your
attic!!!
>> >*IF* a walk-in freezer had its condenser inside the store, the store
>> >would have
>> >to have an air conditioner to remove the heat from the room air. Really
>> >large walk-in coolers and freezers have their condensers outdoors just like
a
>> >central air conditioner.
>> I believe that many don't.
They either have a condenser outdoors (maybe on the roof), they vent into the
room air were an air conditioner moves the heat again, this time to the outdoors
or some may have a water cooled condenser where the heat is removed down the
drain (so to speak).
>> >>I've never tried it, but I'd think that you could cool a room even if
>> >>the air conditioner was sitting on a chair in the room.
>> >From my previous post:
>> >
>> >>>If you realize the way an air conditioner works is by moving heat from
>> >>> inside to room to outside it will be easier to understand the problem
>> >>> with this.
>> >So keeping that in mind, you move the heat from the front of the air
>> >conditioner to the rear of the air conditioner so the room air can adsorb
>> > that heat again.
>> >Then you add the heat generated by the motor and compressor with a net
>> >effect of increasing the room temperature.
>>
>> Taking all that into account, then, I'd think it could be done if you
>> have the proper size a/c...thereby minimizing running time.
>> Theoretically, COULD it be done? Couldn't an a/c just keep recycling
>> the air within the room?...until the optimum temperature is achieved?
No. You're robbing Peter to pay Paul (as the saying goes).
Any heat you remove from the room you put right back into that same room PLUS
the heat generated by the motor and compressor. You haven't "removed" any heat,
just **moved** it. IT IS STILL IN THE ROOM!!
Sorry for the outburst.
If you're not going to believe us, try it in your cottage bedroom when it's
really, really hot and see how well it works. Please do report back your
findings.
Dan O.
Dan O. wrote in message ...
>
>>> >>I've never tried it, but I'd think that you could cool a room even if
>>> >>the air conditioner was sitting on a chair in the room.
>
>>> >From my previous post:
>>> >
>>> >>>If you realize the way an air conditioner works is by moving heat from
>>> >>> inside to room to outside it will be easier to understand the problem
>>> >>> with this.
>
>
>>> >So keeping that in mind, you move the heat from the front of the air
>>> >conditioner to the rear of the air conditioner so the room air can adsorb
>>> > that heat again.
>
>>> >Then you add the heat generated by the motor and compressor with a net
>>> >effect of increasing the room temperature.
>>>
>>> Taking all that into account, then, I'd think it could be done if you
>>> have the proper size a/c...thereby minimizing running time.
>
>>> Theoretically, COULD it be done? Couldn't an a/c just keep recycling
>>> the air within the room?...until the optimum temperature is achieved?
>
>No. You're robbing Peter to pay Paul (as the saying goes).
>
>Any heat you remove from the room you put right back into that same room PLUS
>the heat generated by the motor and compressor. You haven't "removed" any heat,
>just **moved** it.
I thought of another example that may help to illustrate the point.
Think of your room air as the water in a swimming pool. Now you get a pump that
takes hot water from the deep end of the pool and dumps it into the shallow end.
Is the pool any cooler?
FWIW
Edwin Pawlowski
"Dan O." <forum@_NO-JUNK_appliance411.com> wrote in message
>
that
> takes hot water from the deep end of the pool and dumps it into the
shallow end.
> Is the pool any cooler?
>
> FWIW
>
> Dan O.
No, but if you pee in the pool at the same time it will be warmer.
Ed
e...@snet.net
http://pages.cthome.net/edhome
Sirs39
>that
>takes hot water from the deep end of the pool and dumps it into the shallow
>end.
>Is the pool any cooler?
How long should the pump run?
(couldn't resist)
:)
Arturo Jaime'
> Plus what does the manufacturer of the product
> say about that. Now a days they all have 800 No's. you can call, and web pages
> you can go to and email them etc.
Now a days eh? Whata revelation! I knew you'd been asleep for the last 20
years..
d-birdy
"Arturo Jaime'" <u_g...@neverhappen.com> wrote in message
news:3D0218F6...@neverhappen.com...
read that book back when I was a kid and i could never figure out how he
could sleep for 20 years and not have to eat or drink or shit or piss. I
still wonder about it now. does anybody really believe that it could really
happen or am I the onliest one?
d-birdy
David Combs
Dan O. <forum@_NO-JUNK_appliance411.com> wrote:
>
>
>
>Any heat you remove from the room you put right back into that same room PLUS
>the heat generated by the motor and compressor. You haven't "removed" any heat,
>just **moved** it. IT IS STILL IN THE ROOM!!
Why buy an air-conditioner to try this? That's
good money gone.
You know the expression, "if you're too hot,
get out of the kitchen"?
Old wife's tale, now that we live in
these modern times (thanks to T. A. Edison).
Want the kitchen cooler while you spend all
day in there cooking one huge and fancy dinner?
You've *already* got an air-conditioner
in there -- maybe even two!
Just prop-open the door to the refrigerator,
and also to that separate freezer you might
have.
Obviously, close the doors to the kitchen,
the windows to the hot outdoors -- why
cool the outdoors?
And, even better trick is to turn the
thermostats on it (them) to the coldest
possible, since you've got to suck
up all that heat from the stove.
<g>
Cheers!
David
Don Klipstein
>Just prop-open the door to the refrigerator,
>and also to that separate freezer you might
>have.
I hope nobody takes this seriously. Refrigerators and freezers do not
destroy heat nor convert it to anything else. They merely pump heat from
their insides to their outsides. As for a net heat effect, a refrigerator
is a heat source, with the electricity it consumes being converted to
heat.
- Don Klipstein (d...@misty.com)
Dan O.
>>and also to that separate freezer you might
>>have.
I seen Homer do that on an episode of The Simpson's. Even his fridge broke down
becuase of it.
Dan O.