Car fridge as a DIY Cooler?

[Stuart Halliday]

I was wondering about those Coolers used on PCs and small fridges we
see on sale in the shops.

These use a large semiconductor diode called a Peltier Device
(basically a large slab of silicon).
When you apply a DC current through it, one side gets cold as the
electrons move to the otherside where you fit a heatsink and a fan to
thatside to disipate the heat.

So if people uses these devices in a small Fridge, Beer cooler or even
to cool computer chips I could take one of these apart and use it on
my Aquarium?

So is there any reason why can't I just slap the cold side to the side
of my Aquarium glass (on the outside of course)?

I've only got a 60litre Aquarium.

I've came across one product using this device. But it has a water
pump instead of just applying it to the glass itself.
http://www.fritzpet.com/chillermicro.html


Comments?




Photos of a Peltier.
http://www.peltier-info.com/photos.html

[George Pontis]

In article >,
says...
> I was wondering about those Coolers used on PCs and small fridges we
> see on sale in the shops.
>
> These use a large semiconductor diode called a Peltier Device
> (basically a large slab of silicon).
> When you apply a DC current through it, one side gets cold as the
> electrons move to the otherside where you fit a heatsink and a fan to
> thatside to disipate the heat.
>
> So if people uses these devices in a small Fridge, Beer cooler or even
> to cool computer chips I could take one of these apart and use it on
> my Aquarium?
>
> So is there any reason why can't I just slap the cold side to the side
> of my Aquarium glass (on the outside of course)?
...

I assume that you are talking about using one of these for cooling ? If only for
heating then you have many good and inexpensive choices for an aquarium heater.

These devices have several limitations. The most significant is that their
efficiency is very low, less than 1/3 that of a conventional refrigeration system
using a mechanical compressor. So if you need 5W of cooling you are probably going
to have to put in 50W of power or more into it. This will result in much waste
heat that has to be carried away from the "hot" side.

Also, the efficiency depends on the temperature difference between the hot side
and cold side temperatures. It is best when they are near the same temperature,
which implies a really good method of keeping the hot side cool, such as a large
heat sink and fan. You would not want the cold side to get any cooler than the
object you are trying to cool either, since that again increases the temperature
differential across the device and reduces the efficiency. This is the problem
with sticking it on the glass. Glass is not a good thermal conductor. Acrylic is
even worse. The heat would not flow well through the glass, which might lead to a
significant temperature difference across the glass, again reducing the
efficiency. The commercial unit that you saw with a water pump can use metals or
thin ceramics and flowing water, which can transfer heat much better than the
thick glass of an aquarium wall. They can also control the way they get heat from
the hot side and dissipate it into the air. So perhaps they get an efficiency that
is usable for light duty cooling applications.

[[email protected]]

You can make your own chiller from a small freezer by simply using a
cheap inline pump and run the hose into the freezer through a drilled
hole in the freezer's side and coil the hose in the freezer and run the
hose out the other side through another drilled hole, and keep the
freezer door shut for maximum efficiency. This trick supposedly works
great for cold water fish like north american native fish and cold
water marine (north pacific fish in particular). Good luck, later!

[Dances_With_Ferrets]

Interesting that this subject came up..... I recently had one of my
regular customers in the store with his sal****er reef tank overheating
and I told him how to build his own chiller by purchasing one of those
cheapo Wal-mart mini-fridges, drilling it on two sides and running as
many coils of PVC piping through it as could fit without restricting
internal air movement.... aside from a minor issue with
improperly-sealed piping... it worked nicely. I even taught him how to
put the fridge on a thermostatically-controlled plug so that it would
automatically kick on when the tank got too warm. Not the most
efficient chiller, but it worked well and cost about 1/5 the price of a
standard "reef chiller" sold by aquatic supply companies.

[Desmond Wong]

I am using an ice-probe on my tank and that works fine (65L)


"Stuart Halliday" > wrote in message
om...
>I was wondering about those Coolers used on PCs and small fridges we
> see on sale in the shops.
>
> These use a large semiconductor diode called a Peltier Device
> (basically a large slab of silicon).
> When you apply a DC current through it, one side gets cold as the
> electrons move to the otherside where you fit a heatsink and a fan to
> thatside to disipate the heat.
>
> So if people uses these devices in a small Fridge, Beer cooler or even
> to cool computer chips I could take one of these apart and use it on
> my Aquarium?
>
> So is there any reason why can't I just slap the cold side to the side
> of my Aquarium glass (on the outside of course)?
>
> I've only got a 60litre Aquarium.
>
> I've came across one product using this device. But it has a water
> pump instead of just applying it to the glass itself.
> http://www.fritzpet.com/chillermicro.html
>
>
> Comments?
>
>
>
>
> Photos of a Peltier.
> http://www.peltier-info.com/photos.html

[[email protected]]

Pretty cool idea - I would use hose in mine though instead of pipes.
Sorry for the pun!

[Quatermass]

Oh great idea.

I've got a mini-fridge in the loft.

I was just wondering what I'd do if my tank gets too hot in summer.

This sounds like an excellent idea!

Thanks.