Mini Air Conditioner

[Mike]

My room with my electronics and computer stuff gets really warm when its all on. and with summer coming, its only going to get hotter.<p>Is there a simple way to build a small air conditioner just to keep it cool in here? I don't want to mess with compressors and stuff. I'm thinking of one of those thermalelectric pads, a big heatsink on it acting in the opposite way, getting cold, and then a fan. Would that even do anything to cool the room down?

[MrAl]

Hello Mike,<p>I was thinking of doing something like that
myself for a small animal air conditioner.
It would of course use a peltier device.<p>The main problem is not if it will work or not,
but how to get it to work correctly. To start
with, you need a heatsink on the cold side
AND another heatsink on the hot side. The
heatsink on the hot side preferrably has to
be outside the room (like outside the house walls)
in order to get the heat out of the house.
This might work if it was mounted in a window like
a typical ac unit if you had enough peltier
devices and a nice power supply to power them
with.<p>Another possibility is to use water cooling
on the hot side. The water would move the
heat to a radiator that could be located
outside the house.
A water/radiator system on the cold side
would be nice too and probably allow pushing
more air through it to get it circulating.<p>You'll probably have to start with at least
10 peltier devices to get any decent enough
cooling for a small room. Im not even sure
if that would be enough
You'll also need a hefty power supply.<p>For my own cooling, i prefer a small window ac
unit of say 5000 btu. It's already built so
you dont have to do lots of work to get it
going. They arent that expensive in the US
i dont know about other places.<p>Let us know if you build up something?<p>Take care,
Al

[Chris Smith]

From a cost and efficiency point of view, room size, BTUs, etc, its not cost effective. <p>Get a small wall mount AC. <p>Peltiers are expensive and suck up lots of amps, and their real advantage is no moving parts, small size, etc, for electronic fitting of coolers.

[jollyrgr]

I have to agree with Chris. I've played with Peltiers and they are useful for cooling microprocessors and for thermoelectric coolers. At my local home improvement center they had a 6000 BTU air conditioner for $99. A Peltier large enough to cool a small cooler cost about $20. You do the math. From an electrical stand point you will probably waste more energy with the Peltiers than with a compressor based AC.<p>
Mike, you are in the same area as me so you will know about Menards. They are the store that has the 6000 BTU AC for $99.<p>[ June 02, 2004: Message edited by: Jolly Roger ]</p>

[Mike]

yes, i do know about menards.<p>Another problem I face is that its in a room in the basement, so there is no access to the outside for the heat to get out.<p>just wondering how do those mini refrigerators for a car work? they have a cold/hot switch.

[MrAl]

Hi again Mike,<p>I prefer a standard window unit myself, but
if you have a special circumstance then that's
different. The trouble with any kind of cooling
system is that there has to be a way to get
rid of the heat, which is normally expelled to
the outdoors. Some basements have small windows
where you can fit a small ac unit. If your's
has a window too small, then yes you may end up
building something yourself, but it wont be
easy.
If you're willing to run some pipes i would
suggest water cooling, where the pipes run
outside (though a wall or small window)
to a radiator. The heat is carried by the
water to the radiator where it is expelled
into the outside air.<p>I guess it all depends on how much you are
willing to spend and how much effort you
want to put into it and what kind of efficiency
you are after.<p>You could also contact a commercial ac company
to get a quote on having THEM install something
custom. While perhaps a little pricey,
at least you know it will work.<p>Take care,
Al

[Chris Smith]

There are no excuses, heat is heat, and no matter how you intend to get rid of it, you still have to get rid of it. <p>Peltiers, Freon, same problem. <p>Heat in, dump it some where. <p>No free bees in life.

[perfectbite]

If you have absolutely no outside access for a refrigerant gas condenser (the part that gets 'rid' of the waste heat) consider using an insulated, water filled 55 gal. food drum (e.g. bakery corn syrup) the insides are thinly coated, and making that the waste heat storage sump. Take an angled $99.00, 6KBTU unit (angled so that the water doesn't flood the electrical side of the air conditioner) and trickle/recirculate the water from the 55 gal. drum over the condenser coil (that way you won't have to recover the refrigerant charge, do a nitrogen flush before repiping the condenser to its new location and having to put the refrigerant charge (it'll need slightly more to allow for the extended pipe runs) back into the unit). It may work well on a daily basis for a few for a few hours or more. The law of diminishing returns will get you eventually. At a set drum temp. pump that somewhat heated water to a roof space cistern tank for use as shower or warm water clothes or dish washer water on a daily basis (or even pump it to a rainbarrel for use in your garden) and allow cold city water to refill the 55 gal. drum. Make allowances for a complete seasonal draining and drying out of that sump tank otherwise buy a stainless steel tank. <p>I researched Peltier 'coolers' and found that even though they are very handy low voltage devices they truly are Amp hogs. For a basement area you would still have to get rid of the Peltier's waste heat too and they would be too busy handling all of the heat from all the required heavy duty wall warts to cool you off.

[jwax]

Is there a window nearby on the floor above you? Maybe a window unit up there, and creativly duct its cold air outlet down to your hot basement? Cold air, being denser, will drop anyway. Maybe just a floor grate above you to an air conditioned room?

[Mike]

well, we already have a full house AC system, but there are no ducts in the room. And, when the system isn't on (like when almost every other room in the house is on), i need a way to get the air cool. <p>I don't like the idea of modifying an AC unit for water cooling, and nor the idea of sticking it in the wall upstairs.<p>Finally, this room is right next to the furnace room, so there the heat woulnd't matter.<p>Another problem is that the room is very small, and there is no room for a full-size window AC unit. Thats why I asked about building one.

[perfectbite]

If the make up air coming into that room is relatively dry (low humidity) then consider a creature comfort swamp cooler. Leave the door to the room open and let the whole house A/C unit take care of the increased humidity 'knock down' water otherwise you'll have a dank and dripping cool basement.

[rshayes]

Since you have no way to transport heat out of the room, it might be better to transport cold in. A 50 pound block of ice might last for a couple of days, and the heat is removed when you remove the water from the melted ice. The old iceboxes would last about a week, but they were better insulated and had, I assume, a smaller volume to cool. You did say a small room, but I doubt if is that small.

[Will]

I posted a reply on this subject a couple of days ago - but it doesn't seem to have made it there - This is just a trial to see if it gets through this time

[jollyrgr]

If there is no window/opening to vent the heat Peltier devices or compressor based AC units will not work. All you can do is move heat from where it is objectionable to a place where it does not matter. Since you have a room in the basement the solution should be easy. Find the plenum for the OUTPUT air from the furnace. This will usually be a sheet metal box extending across the entire basement. Cut a hole in the sheet metal so that it will accept a register grate and fasten that grate to the sheet metal using self tapping screws. If the room where it is too hot does not have the plenum directly above it, simply use a five or six inch diameter piece of duct work to extend the airflow to where you need it. They even have flexible duct work that can be bent into whatever shape you need. If you cannot find the furnace flexible duct work you could use METAL (foil) dryer vent pipe. (DO NOT USE PLASTIC DRYER VENT PIPE!!!!) But that would only be about a four inch diameter pipe. If the basement has a dropped ceiling tile arrangement, fasten the grate to the ceiling tile and extend the duct work (metal, flexible) to a point just above the vent.

[keymaker]

Is there any way to mount a window a/c in the ceiling?? Do you have a drain in the basement you could route the water too?<p> And duct the hot air outside?<p>
Would that work?