Anyone know anything about Peltier coolers. A friend of mine wants to cool
12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I don't
think it's powerful enough. As far as I know she doesn't have any specs on
it.
So the questions a
Is this a good way of cooling in this situation? Got any better suggestions?
Would house insulation sheet foam on 5 sides make an appreciable difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl

Karl Vorwerk wrote:
Anyone know anything about Peltier coolers. A friend of mine wants to cool

A little bit, I'm using one to cool my CPU.

12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I don't
think it's powerful enough. As far as I know she doesn't have any specs on
it.

You might try this place for research info: http://www.peltier-info.com/

So the questions a
Is this a good way of cooling in this situation? Got any better suggestions?

Probably not the best way. Peltiers only cover a limited area, and you
have to come up with some way to remove the waste heat before it leaks
back to the cold side. I'm not sure of a better way. Maybe taking a
mini-fridge and removing the door and attaching it to one sode of the
vivarium?

Would house insulation sheet foam on 5 sides make an appreciable difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl

Sorry I wasn't much help, but hopefully I pointed you to some good info.
Todd

Just wondering, what kind of temps your getting and what cpu and is it
overclocked? I am watercooling, and enjoy it so much more over air. Easy 16
degrees C cooler, and a whole lot quieter. Are you still using air to move
the heat off the sink on the warm side of the pelt?

"Todd Rich" wrote in message
...
Karl Vorwerk wrote:
Anyone know anything about Peltier coolers. A friend of mine wants to
cool

A little bit, I'm using one to cool my CPU.

12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers
got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I
don't
think it's powerful enough. As far as I know she doesn't have any specs
on
it.

You might try this place for research info: http://www.peltier-info.com/

So the questions a
Is this a good way of cooling in this situation? Got any better
suggestions?

Probably not the best way. Peltiers only cover a limited area, and you
have to come up with some way to remove the waste heat before it leaks
back to the cold side. I'm not sure of a better way. Maybe taking a
mini-fridge and removing the door and attaching it to one sode of the
vivarium?

Would house insulation sheet foam on 5 sides make an appreciable
difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl

Sorry I wasn't much help, but hopefully I pointed you to some good info.
Todd

Grady wrote:
Just wondering, what kind of temps your getting and what cpu and is it=20
overclocked? I am watercooling, and enjoy it so much more over air. Easy=
16=20
degrees C cooler, and a whole lot quieter. Are you still using air to mo=
ve=20
the heat off the sink on the warm side of the pelt?

I'm getting about 55=B0F-60=B0F (12-16=B0C), on a AMD 1600+, not overclock=
ed,=20
mainly because my chip/mb combo isn't the best. However I'll be moving=20
to an A64 system designed to overclock in a few months, so I'm working=20
out the kinks in my cooling now.=20

I'm using a Danger Den Maze4-1 water cooling setup to cool the hot side of=
=20
the peltier. I've got a heater core that fits 2 120mm fans to dump the=20
heat into the air. I could go a lot cooler with a phase-change setup, but=
=20
one of the main reasons I got into watercooling in the first place was to=20
cut down on the noise. I'm also going to be building my own case because=20
even though I've got a full-tower, it routes all my hoses and cable=20
through a 3"x4" hole from the top to the bottom. I like room to work=20
around in, because I do a lot of incremental upgrading. Though the case=20
will be uv-reactive acrylic rather than metal.=20=20

Ob metal content:

I'm planning on machining out a new coldplate out of silver for it's=20
better thermal conductive properties. That might get me an extra couple=20
of degrees C.

Todd

Karl Vorwerk wrote:
Anyone know anything about Peltier coolers. A friend of mine wants to cool
12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I don't
think it's powerful enough. As far as I know she doesn't have any specs on
it.
So the questions a
Is this a good way of cooling in this situation? Got any better suggestions?
Would house insulation sheet foam on 5 sides make an appreciable difference?

Yes!

Can you define "very much" in F?
In general, peltiers will move about the same amount of heat as they use.

So, if the DC adaptor is 20W, it's going to take in 20W of heat, and put
it out as 20W at a higher temperature, combined with the 20W of electrical
power.

What sort of lighting is being used?
Seperating the lighting out into a seperate container, with a fan added will
reduce heat gain that way.

I don't know what I did wrong with my plastic case but it seems that metal
shielding is needed. I couldn't keep a monitor within 5' of the box and had
problems with the cordless phone on the desk. I'm all metal now.


"Todd Rich" wrote in message
...
Grady wrote:
Just wondering, what kind of temps your getting and what cpu and is it
overclocked? I am watercooling, and enjoy it so much more over air. Easy
16
degrees C cooler, and a whole lot quieter. Are you still using air to move
the heat off the sink on the warm side of the pelt?

I'm getting about 55°F-60°F (12-16°C), on a AMD 1600+, not overclocked,
mainly because my chip/mb combo isn't the best. However I'll be moving
to an A64 system designed to overclock in a few months, so I'm working
out the kinks in my cooling now.

I'm using a Danger Den Maze4-1 water cooling setup to cool the hot side of
the peltier. I've got a heater core that fits 2 120mm fans to dump the
heat into the air. I could go a lot cooler with a phase-change setup, but
one of the main reasons I got into watercooling in the first place was to
cut down on the noise. I'm also going to be building my own case because
even though I've got a full-tower, it routes all my hoses and cable
through a 3"x4" hole from the top to the bottom. I like room to work
around in, because I do a lot of incremental upgrading. Though the case
will be uv-reactive acrylic rather than metal.

Ob metal content:

I'm planning on machining out a new coldplate out of silver for it's
better thermal conductive properties. That might get me an extra couple
of degrees C.

Todd

I doubt you will find it efficient enough. The industry has chillers
for aquariums usually with a titanium coil for water contact. These are
conventional refrigeration units with compressors.
I don't know how well they would work in a situation chilling air.
All I could think of using the solid state modules was setting the
terrarium in a tray of water and chilling the water. Seems to me you
only need to cool the lower portion of the terrarrium, slamanders tend
to stay low.

wrote in message
oups.com...
I doubt you will find it efficient enough. The industry has chillers
for aquariums usually with a titanium coil for water contact. These are
conventional refrigeration units with compressors.
I don't know how well they would work in a situation chilling air.

they won't cool air at all. the inner coils would get cold and perhaps ice
up similar to an old non-selfdefrost freezer .

All I could think of using the solid state modules was setting the
terrarium in a tray of water and chilling the water. Seems to me you
only need to cool the lower portion of the terrarrium, slamanders tend
to stay low.

Karl Vorwerk wrote:

Anyone know anything about Peltier coolers. A friend of mine wants to cool
12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I don't
think it's powerful enough. As far as I know she doesn't have any specs on
it.
So the questions a
Is this a good way of cooling in this situation? Got any better suggestions?
Would house insulation sheet foam on 5 sides make an appreciable difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl


Peltier's are inefficient (you've been told that). They conduct heat as
well or better than they pump it (they're metal). You want to have a
BIG heatsink/radiator on the hot side and a BIG heatsink/radiator on the
cold side. With fans. Insulating the vivarium would be a good idea.

I heard a suggestion to use a mini-fridge -- I second that, but get a
real one with a compressor. Or use water cooler, set the water
temperature & circulate it through the vivarium (probably closed-cycle
through some piping in the soil). Make sure that getting too cold won't
hurt the little beasty, and if so put in some failsafes on the
temperature regulation.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Use thermal mass IE water from the fridge. Perhaps the peltier would add
additional cooling to it. Betcha a gallon from the fridge a day would
work if it isn't in a sunny window.
Plan: bottom of vivarium has small stone deep enough that a gallon
leaves the top dry. little aquarium pump pumps water from another 1
gallon reservior outside the tank. Can pump it through a small heat
exchanger for the peltier. Every day you take a fresh gallon of tap
water out of the fridge and change out your external reservior. Insulate
the bottom third of the tank to keep water cool. When the evap cooling
effect is added, bet it works. Cheep too.

Salamander would seem a boring pet




Tim Wescott wrote:
Karl Vorwerk wrote:

Anyone know anything about Peltier coolers. A friend of mine wants to
cool 12"x15"x30" glass vivarium a maximum of 20-30 degrees
farienhieght below ambient temperature. It's long term for a
salamander. A friend of hers got her a surplus Peltier cooler. Which I
installed. It didn't drop the temperature very much inside the
vivarium. After doing some research I don't think it's powerful
enough. As far as I know she doesn't have any specs on it.
So the questions a
Is this a good way of cooling in this situation? Got any better
suggestions? Would house insulation sheet foam on 5 sides make an
appreciable difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl


Peltier's are inefficient (you've been told that). They conduct heat as
well or better than they pump it (they're metal). You want to have a
BIG heatsink/radiator on the hot side and a BIG heatsink/radiator on the
cold side. With fans. Insulating the vivarium would be a good idea.

I heard a suggestion to use a mini-fridge -- I second that, but get a
real one with a compressor. Or use water cooler, set the water
temperature & circulate it through the vivarium (probably closed-cycle
through some piping in the soil). Make sure that getting too cold won't
hurt the little beasty, and if so put in some failsafes on the
temperature regulation.

Peltier coolers will move several watts of heat from the cold side to the
hot side but you do need to make sure that you have a big enough cooler to
do the job.
Insulating the enclosure will decrease the amount of heat getting into the
enclosure and this helps allow the device to work well. Look at the car
cooler for how much insulation that you need to really get a decent
temperature drop. IN addition, you also need to be able to remove the heat
and cold from the peltier device or you will be making a cold spot that
really doesn't cool the whole enclosure.Water (actually antifreeze) pipes on
the cold side have the problem of often freezing water as a single stage
cooler can easily hit temps that low if there isn't a lot of heat input to
the cooler. Also, removal of the heat from the hot side will increase the
efficiency as the coolers work better at low temps than at high temps in
addition to the fact that they produce a diffeerential of temp across them
according to the current tht is run through them and the amount of heat that
is being movrf.
I like to run my coolers at about 50-75% of their capacity to keep them at
their efficient range. I'll note that you can run several peltier coolers
in series as long as they are of the same type device - junction count
doesn't care but the individual junction type (peltier devices are made up
of a large number of individual pellets of the junction material). This can
make the construction of the power supply a lot easier as lower currents can
be had which reduces the size of the parts.
Basically, insulate well, move the heat quickly and run enough of the
devices to move all of the heat you do have to move. If one won't do the
job, add more and eventually you will move enough heat to cool to the temps
you want.
I've made some stacks (cold to hot sides of several devices, each lower in
temp of the stack a smaller size) and gotten temps down below -40 with these
devices.

--
Why isn't there an Ozone Hole at the NORTH Pole?

Peltier devices (also known as TEC, thermo-electric coolers, and TEG,
thermo-electric generators)
are solid state devices that transfer heat (or cold) from one side of the
device to the other. Or, they'll
produce a voltage in response to a temperature differential. The normal
temp differential from the
"hot" side to the "cold" side of the device is about 50 degrees Celsius (a
LOT more than any pet would
like), BUT you still need to move the heat off the "hot" side if you're
trying to cool (think heat sink and
fan) AND circulate the air on the "cold" side. It is really made for
cooling surfaces, I don't know how
successful you'll be in cooling air. Why don't you report back if you
pursue this?

George

BTW--You supply a DC voltage to the Peltier device to get it to cool/heat
and you may need to look
up its specs to find out exactly what voltage to supply. Also, Peltier
devices tend to be small and pricey.

"Karl Vorwerk" wrote in message
...
Anyone know anything about Peltier coolers. A friend of mine wants to cool
12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I
don't
think it's powerful enough. As far as I know she doesn't have any specs on
it.
So the questions a
Is this a good way of cooling in this situation? Got any better
suggestions?
Would house insulation sheet foam on 5 sides make an appreciable
difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl

George wrote:

Peltier devices (also known as TEC, thermo-electric coolers, and TEG,
thermo-electric generators)
are solid state devices that transfer heat (or cold) from one side of the
device to the other. Or, they'll
produce a voltage in response to a temperature differential. The normal
temp differential from the
"hot" side to the "cold" side of the device is about 50 degrees Celsius (a
LOT more than any pet would
like), BUT you still need to move the heat off the "hot" side if you're
trying to cool (think heat sink and
fan) AND circulate the air on the "cold" side. It is really made for
cooling surfaces, I don't know how
successful you'll be in cooling air. Why don't you report back if you
pursue this?

George

Some of the 12v coolers for cars use em for air cooling. Very slow to
actually cool anything but work ok at keeping cold something that's
already cold. Probably just undersized when used in this application
due to cost.

Anyway...because they work based on creating a temperature differential,
isn't there an application where the are stacked to reach VERY cold
temps? You'd have to pump one hell of a lot of heat out of the final
stage but it might be interesting to see just how cold one could get the
cold side.

Koz


BTW--You supply a DC voltage to the Peltier device to get it to cool/heat
and you may need to look
up its specs to find out exactly what voltage to supply. Also, Peltier
devices tend to be small and pricey.

"Karl Vorwerk" wrote in message
...


Anyone know anything about Peltier coolers. A friend of mine wants to cool
12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I


don't


think it's powerful enough. As far as I know she doesn't have any specs on
it.
So the questions a
Is this a good way of cooling in this situation? Got any better


suggestions?


Would house insulation sheet foam on 5 sides make an appreciable


difference?


My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl

On Wed, 09 Feb 2005 11:22:47 GMT, "Karl Vorwerk"
wrote:

Anyone know anything about Peltier coolers. A friend of mine wants to cool
12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I don't
think it's powerful enough. As far as I know she doesn't have any specs on
it.
So the questions a
Is this a good way of cooling in this situation? Got any better suggestions?
Would house insulation sheet foam on 5 sides make an appreciable difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Just one 15" x 30" pane of 1/8" glass will conduct about 730 watts
(4992 BTU/hr) if one side is 30 degF different than the other. That
seems like a lot, but I checked my math several times. I used k for
glass of 0.96 K/(W*m).

However, air is a pretty good insulator. I think if you could create
a "cool region" that is perhaps 6" lower than insulated surroundings,
a little depression, then a cold plate at the bottom of that region
could cool it by 30 deg. With no turbulence, cooled air would stay in
the depression and insulate the region. If the region were 12"
square and 6" deep, the heatflow necessary to maintain a gradient of
30 degF from bottom to top of that air volume would only be about 0.25
watt. A Peltier can easily do that. I'm looking at a Peltier 1.6"
square that can pump about 35 watts with a coldsurface temp of 40F and
a heatsink temp of 80F -- assuming you can keep the warm side of the
Peltier that cool.

If you use a small dorm-size fridge, the best way would probably be to
have a water heat exhanger comprised of a little pump, a coil in the
fridge and plastic water lines to a cold plate in the valley in the
vivarium.

The Hagen Life-Glo aperture bulbs direct light well and run cool.

http://www.wetpetsusa.com/haliflaqbu24.html

That will cut down your heat gain a little.

Insulation on five sides will help. With all that area, heat will flow
in.

But where the problem is, I'd say, is the capacity of the heat pump,
and its interface to the terrarium. A big cold plate well greased to
the glass bottom of the aquarium would work, but would cost as much as
a mini-fridge new. If you had a piece lying around, it'd help a lot
because if you just apply the pump to the glass, you'll just get one
cold spot of glass, not much cooling over the area.

But really, such a small heat pump will not cool reliably if your
ambient goes from 59 to 90.

--Doug
No fancy sig available through Google.

Koz wrote:



George wrote:

Peltier devices (also known as TEC, thermo-electric coolers, and TEG,
thermo-electric generators)
are solid state devices that transfer heat (or cold) from one side of the
device to the other. Or, they'll
produce a voltage in response to a temperature differential. The normal
temp differential from the
"hot" side to the "cold" side of the device is about 50 degrees Celsius (a
LOT more than any pet would
like), BUT you still need to move the heat off the "hot" side if you're
trying to cool (think heat sink and
fan) AND circulate the air on the "cold" side. It is really made for
cooling surfaces, I don't know how
successful you'll be in cooling air. Why don't you report back if you
pursue this?

George

Some of the 12v coolers for cars use em for air cooling. Very slow to
actually cool anything but work ok at keeping cold something that's
already cold. Probably just undersized when used in this application
due to cost.

Anyway...because they work based on creating a temperature differential,
isn't there an application where the are stacked to reach VERY cold
temps? You'd have to pump one hell of a lot of heat out of the final
stage but it might be interesting to see just how cold one could get the
cold side.

Koz
There are small cryo-coolers based on stacks of Peltiers that are used
down to about 100 kelvin. They're like 5 - 7 stages; each stage needs
to have 50% to 100% more area than the last so they look like pagoda
roofs. Around 100K sterling coolers start to gain ground for that sort
of thing.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Ok - I fess up - I used a Peltier cooler for my Intel 8080.

It was a 1" square cooling and 1" square heating surface.

Keep in mind that the cold side must contact using heat sink grease (or the like)
to the 'work' and the hot side must have the same thermal resistance or lower.

It is best to have an massive sink on the hot side - just to get it out of there.

If the hot side isn't cooled (by drawing it off) - then the P-N junctions (semi-conductor)
will heat up and conduction halts. Heat can also kill the p-n junctions.

Mine was a 10 or 20 amp unit - that baby would rock.

I used a massive - Hockey Puck SCR heat sink - size of a shoe box - as the hot sink.

Not logical, but then I couldn't get the heat pipes I wanted at the time.

Martin

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

Thanks didn't see that site yet. I thought of the little fridge idea also.
She never saw a cheap used one. The other suggestion I thought of was a wine
cooler but she didn't want to spend that much.
Thanks
Karl

"Todd Rich" wrote in message
...
Karl Vorwerk wrote:
Anyone know anything about Peltier coolers. A friend of mine wants to
cool

A little bit, I'm using one to cool my CPU.

12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers
got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I
don't
think it's powerful enough. As far as I know she doesn't have any specs
on
it.

You might try this place for research info: http://www.peltier-info.com/

So the questions a
Is this a good way of cooling in this situation? Got any better
suggestions?

Probably not the best way. Peltiers only cover a limited area, and you
have to come up with some way to remove the waste heat before it leaks
back to the cold side. I'm not sure of a better way. Maybe taking a
mini-fridge and removing the door and attaching it to one sode of the
vivarium?

Would house insulation sheet foam on 5 sides make an appreciable
difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl

Sorry I wasn't much help, but hopefully I pointed you to some good info.
Todd

I set up the cold heat sink in the vivarium with a 5" fan and the hot side
sink on the outside with no fan. Mounted through a 3/8" plywood board for
the top of the vivarium.
Thanks
Karl

wrote in message
oups.com...
The Hagen Life-Glo aperture bulbs direct light well and run cool.

http://www.wetpetsusa.com/haliflaqbu24.html

That will cut down your heat gain a little.

Insulation on five sides will help. With all that area, heat will flow
in.

But where the problem is, I'd say, is the capacity of the heat pump,
and its interface to the terrarium. A big cold plate well greased to
the glass bottom of the aquarium would work, but would cost as much as
a mini-fridge new. If you had a piece lying around, it'd help a lot
because if you just apply the pump to the glass, you'll just get one
cold spot of glass, not much cooling over the area.

But really, such a small heat pump will not cool reliably if your
ambient goes from 59 to 90.

--Doug
No fancy sig available through Google.

It's looking bad for the Peltier cooler so far.
Thanks
Karl

wrote in message
oups.com...
I doubt you will find it efficient enough. The industry has chillers
for aquariums usually with a titanium coil for water contact. These are
conventional refrigeration units with compressors.
I don't know how well they would work in a situation chilling air.
All I could think of using the solid state modules was setting the
terrarium in a tray of water and chilling the water. Seems to me you
only need to cool the lower portion of the terrarrium, slamanders tend
to stay low.

Just checked the power supply (Colman peltier cooler power supply). It's
output is 5 amps at 12 volts. I have no idea if the peltier cooler can use
all the current or perhaps more current.
Thanks
Karl

"Martin H. Eastburn" wrote in message
news
Ok - I fess up - I used a Peltier cooler for my Intel 8080.

It was a 1" square cooling and 1" square heating surface.

Keep in mind that the cold side must contact using heat sink grease (or
the like)
to the 'work' and the hot side must have the same thermal resistance or
lower.

It is best to have an massive sink on the hot side - just to get it out of
there.

If the hot side isn't cooled (by drawing it off) - then the P-N junctions
(semi-conductor)
will heat up and conduction halts. Heat can also kill the p-n junctions.

Mine was a 10 or 20 amp unit - that baby would rock.

I used a massive - Hockey Puck SCR heat sink - size of a shoe box - as the
hot sink.

Not logical, but then I couldn't get the heat pipes I wanted at the time.

Martin

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

Make me think wine cooler: less overall trouble and less cooling problem.
She's using an ice pack or two a day right now. She's looking for constant
temp within reason.
I think salamanders are boring too, except if fire salamanders actually
breathed fire.

Thanks
Karl

"Bob May" wrote in message
...
Peltier coolers will move several watts of heat from the cold side to the
hot side but you do need to make sure that you have a big enough cooler to
do the job.
Insulating the enclosure will decrease the amount of heat getting into the
enclosure and this helps allow the device to work well. Look at the car
cooler for how much insulation that you need to really get a decent
temperature drop. IN addition, you also need to be able to remove the
heat
and cold from the peltier device or you will be making a cold spot that
really doesn't cool the whole enclosure.Water (actually antifreeze) pipes
on
the cold side have the problem of often freezing water as a single stage
cooler can easily hit temps that low if there isn't a lot of heat input to
the cooler. Also, removal of the heat from the hot side will increase the
efficiency as the coolers work better at low temps than at high temps in
addition to the fact that they produce a diffeerential of temp across them
according to the current tht is run through them and the amount of heat
that
is being movrf.
I like to run my coolers at about 50-75% of their capacity to keep them at
their efficient range. I'll note that you can run several peltier coolers
in series as long as they are of the same type device - junction count
doesn't care but the individual junction type (peltier devices are made up
of a large number of individual pellets of the junction material). This
can
make the construction of the power supply a lot easier as lower currents
can
be had which reduces the size of the parts.
Basically, insulate well, move the heat quickly and run enough of the
devices to move all of the heat you do have to move. If one won't do the
job, add more and eventually you will move enough heat to cool to the
temps
you want.
I've made some stacks (cold to hot sides of several devices, each lower in
temp of the stack a smaller size) and gotten temps down below -40 with
these
devices.

--
Why isn't there an Ozone Hole at the NORTH Pole?

It came with two 5"x5" heatsinks mounted on it. I mounted the fan on the
cool side but it looks like it should have been the hot side. If I continue
this I'll let everyone know how it comes out.
Thanks
Karl

"George" wrote in message
...
Peltier devices (also known as TEC, thermo-electric coolers, and TEG,
thermo-electric generators)
are solid state devices that transfer heat (or cold) from one side of the
device to the other. Or, they'll
produce a voltage in response to a temperature differential. The normal
temp differential from the
"hot" side to the "cold" side of the device is about 50 degrees Celsius (a
LOT more than any pet would
like), BUT you still need to move the heat off the "hot" side if you're
trying to cool (think heat sink and
fan) AND circulate the air on the "cold" side. It is really made for
cooling surfaces, I don't know how
successful you'll be in cooling air. Why don't you report back if you
pursue this?

George

BTW--You supply a DC voltage to the Peltier device to get it to cool/heat
and you may need to look
up its specs to find out exactly what voltage to supply. Also, Peltier
devices tend to be small and pricey.

"Karl Vorwerk" wrote in message
...
Anyone know anything about Peltier coolers. A friend of mine wants to
cool
12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers
got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I
don't
think it's powerful enough. As far as I know she doesn't have any specs
on
it.
So the questions a
Is this a good way of cooling in this situation? Got any better
suggestions?
Would house insulation sheet foam on 5 sides make an appreciable
difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Karl

I new there was a lot of heat loss through the glass but I didn't have any
idea how much.
I'll keep these two ideas in mind. I'm going to remount the fan on the hot
side and see what happens. I wonder if I could eventually mount the cold
side to the glass bottom of the tank and get enough heat transfer. The tank
needs high humidity.
Thanks
Karl


"Don Foreman" wrote in message
...
On Wed, 09 Feb 2005 11:22:47 GMT, "Karl Vorwerk"
wrote:

Anyone know anything about Peltier coolers. A friend of mine wants to cool
12"x15"x30" glass vivarium a maximum of 20-30 degrees farienhieght below
ambient temperature. It's long term for a salamander. A friend of hers got
her a surplus Peltier cooler. Which I installed. It didn't drop the
temperature very much inside the vivarium. After doing some research I
don't
think it's powerful enough. As far as I know she doesn't have any specs on
it.
So the questions a
Is this a good way of cooling in this situation? Got any better
suggestions?
Would house insulation sheet foam on 5 sides make an appreciable
difference?
My first suggestion was air-condition the room but she doesn't like
air-conditioning. I'm in Hawaii so ambient temperatures are 59-90
farienhieght.
Thanks for any thoughts or suggestions.

Just one 15" x 30" pane of 1/8" glass will conduct about 730 watts
(4992 BTU/hr) if one side is 30 degF different than the other. That
seems like a lot, but I checked my math several times. I used k for
glass of 0.96 K/(W*m).

However, air is a pretty good insulator. I think if you could create
a "cool region" that is perhaps 6" lower than insulated surroundings,
a little depression, then a cold plate at the bottom of that region
could cool it by 30 deg. With no turbulence, cooled air would stay in
the depression and insulate the region. If the region were 12"
square and 6" deep, the heatflow necessary to maintain a gradient of
30 degF from bottom to top of that air volume would only be about 0.25
watt. A Peltier can easily do that. I'm looking at a Peltier 1.6"
square that can pump about 35 watts with a coldsurface temp of 40F and
a heatsink temp of 80F -- assuming you can keep the warm side of the
Peltier that cool.

If you use a small dorm-size fridge, the best way would probably be to
have a water heat exhanger comprised of a little pump, a coil in the
fridge and plastic water lines to a cold plate in the valley in the
vivarium.

On Thu, 10 Feb 2005 11:43:25 GMT, "Karl Vorwerk"
wrote:

I new there was a lot of heat loss through the glass but I didn't have any
idea how much.
I'll keep these two ideas in mind. I'm going to remount the fan on the hot
side and see what happens. I wonder if I could eventually mount the cold
side to the glass bottom of the tank and get enough heat transfer. The tank
needs high humidity.

That might work. You might want an aluminum spreader plate, maybe 6"
square and 1/4" thick, insulated from ambient air, with some heatsink
grease between the plate and the glass. The gradient in the bottom
glass would then be about 0.25 degF/watt. Might want some insulation
on the lower parts of the sides.

I wonder if you'd get a little fogbank or cloud near the bottom!

On Thu, 10 Feb 2005 11:20:06 GMT, "Karl Vorwerk"
wrote:

Just checked the power supply (Colman peltier cooler power supply). It's
output is 5 amps at 12 volts. I have no idea if the peltier cooler can use
all the current or perhaps more current.

The Peltier I have may have been surplus from Coleman. It's a 1.56"
square white ceramic thing about .140" thick, with a red wire and a
black wire affixed. If yours sounds similar, I have a somewhat blurry
but readable specsheet. It is 12 volts at 5 amps at some
temperatures.

On Thu, 10 Feb 2005 10:47:45 GMT, "Karl Vorwerk"
wrote:

Thanks didn't see that site yet. I thought of the little fridge idea also.
She never saw a cheap used one. The other suggestion I thought of was a wine
cooler but she didn't want to spend that much.
Thanks
Karl

Wal-mart and Target often have little fridges for under $50 ($30 if on
sale) in the Camping or Automotive sections.

Don Foreman wrote:

On Thu, 10 Feb 2005 11:43:25 GMT, "Karl Vorwerk"
wrote:


I new there was a lot of heat loss through the glass but I didn't have any
idea how much.
I'll keep these two ideas in mind. I'm going to remount the fan on the hot
side and see what happens. I wonder if I could eventually mount the cold
side to the glass bottom of the tank and get enough heat transfer. The tank
needs high humidity.


That might work. You might want an aluminum spreader plate, maybe 6"
square and 1/4" thick, insulated from ambient air, with some heatsink
grease between the plate and the glass. The gradient in the bottom
glass would then be about 0.25 degF/watt. Might want some insulation
on the lower parts of the sides.

I wonder if you'd get a little fogbank or cloud near the bottom!

The inside of the outer wall of the double wall box is the hot side.
The outside of inner wall is the cold side. Between the two walls is
foam and in one spot the cooler. The outside will radiate to the world
easily enough the heat given off by the bottles and passed through
the only leakage path - that of the Peltier cooler.

Martin

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

This one seems to be around 3" square by 1" tall. It's rapped in foam. Red
and Black wire sticking out of it.
Karl

"Don Foreman" wrote in message
...
On Thu, 10 Feb 2005 11:20:06 GMT, "Karl Vorwerk"
wrote:

Just checked the power supply (Colman peltier cooler power supply). It's
output is 5 amps at 12 volts. I have no idea if the peltier cooler can use
all the current or perhaps more current.

The Peltier I have may have been surplus from Coleman. It's a 1.56"
square white ceramic thing about .140" thick, with a red wire and a
black wire affixed. If yours sounds similar, I have a somewhat blurry
but readable specsheet. It is 12 volts at 5 amps at some
temperatures.

Xane T. wrote:
On Thu, 10 Feb 2005 10:47:45 GMT, "Karl Vorwerk"
wrote:

Thanks didn't see that site yet. I thought of the little fridge idea also.
She never saw a cheap used one. The other suggestion I thought of was a wine
cooler but she didn't want to spend that much.
Thanks
Karl

Wal-mart and Target often have little fridges for under $50 ($30 if on
sale) in the Camping or Automotive sections.

Many of these may be peltier based.

I'd doubt the 1" thickness as Peltier modules are a lot thinner than that
normally. Even the xy directions are a bit dubious as the largest normally
are in the inch and a half size. You may have some axuilary parts put onto
the module to help get the heat moved about.
You get to pump about 180BTU of heat with a single module for the most part
and anything as big as you are discussing should be able to handle about 4
times that if the size of the actual device is that big.

--
Why isn't there an Ozone Hole at the NORTH Pole?

On Fri, 11 Feb 2005 12:46:50 -0800, the renowned "Bob May"
wrote:

I'd doubt the 1" thickness as Peltier modules are a lot thinner than that
normally. Even the xy directions are a bit dubious as the largest normally
are in the inch and a half size.

A lot are 40mm x 40mm x 5mm (roughly) thick.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

The thickness is approximately 1 inch between the faces of the heatsinks. I
haven't tried pulling it apart yet as my friend is trying to get specs on
it. I'll post whatever info I get.
Thanks
Karl

"Bob May" wrote in message
...
I'd doubt the 1" thickness as Peltier modules are a lot thinner than that
normally. Even the xy directions are a bit dubious as the largest
normally
are in the inch and a half size. You may have some axuilary parts put
onto
the module to help get the heat moved about.
You get to pump about 180BTU of heat with a single module for the most
part
and anything as big as you are discussing should be able to handle about 4
times that if the size of the actual device is that big.

--
Why isn't there an Ozone Hole at the NORTH Pole?