Summer project - peltier cooling

I know how people are generally loth to read a huge long post, so I will make it as short as possible...

So I have decided to upgrade to peltier cooling, having about 11 weeks free time to make a good job of it

First question I have regards the "cold plate", the metal plate between the CPU and the cold side of the element (I assume).

I have an old CPU heatsink that seems to be of composite construction, an aluminium heatsink on top of a copper baseplate. I intend to recover the copper plate and modify it to be part of a peltier construction. The plate is 2mm thick, is this about the right thickness? I have acess to a machine shop so I can make modiifications to things like that.

Secondly, a summary of what I intend to do:

Peltier & cold plate on top of CPU enclosed in perspex compartment, sealed with silicone to prevent condensation. (Before I seal it I would put some silica gel in there to dessicate the air)

Peltier cooled by water, which is in turn cooled by being pumped through pipe coils in a fridge

Just collecting advice at present, I will start building as a summer project some time soon...

get a camera and be sure to post pics

2mm is a bit too thin. Try more like 6mm. I dont know a huge amount about peltiers but im pretty sure 2mm wont work very well.

I would have thought 2mm would be better? Less metal between the CPU and peltier?

Or am I just being very naive and are there in fact other factors like the volume of the coldplate relative to how much heat it can store, etc...

Well the theory behind the cold plate is that it allows the heat of the small cpu die to spread to the entire area of the pelt. It needs this because heat can only transfer through the pelt in a straight line. 2mm is generaly too thin to allow the heat to spread out enough. That said there is a sweet spot in thickness which takes into account the point you made. The sweet spot depends on alot of factors but IME most people tend to use coldplates that are around 6mm

here is an article from (billA) the OC front page: http://www.overclockers.com/articles305/

edit: thicker = better (to a point). weight and cost must be kept in mind

Excellent, I did overlook the sideways heat-spreading thing.

Thanks people

idunoo if you already though about this but you will probably still need a radiator. With the pelt and cpu you have to remove something like 300 watts of heat. I don't know if many fridges can handle this kind of constant load. Expecially if you mean a mini fridge.

if you have access to a machine shop, get some raw copper from onlinemetals.com and machine one.

I thought of that idea about the clear plastic box insulation, its an awesome idea and can very possibly work really well. One thing I would do differently is use nitrogen or something instead of regular air. You might also want to doulble thickness it with an air gap, kinda like how windows are.

youll probably have to do the back of the motherboard aswell, either that or just neopreme it.

Jon