[avandonk]

I use a modified Peltier fridge to cool my Canon 5D camera for astrophotography. See image below. There are two CPU heatpipe coolers cooling two 40x40 mm Peltiers. I am powering them at a maximum of 14V and 6A each. This is about 80W+ of real cooling. I have a PID controlling the cold side of the heat exchangers to within 0.1C.

The maximum temperature drop I can get is about 24C from ambient. Ths is fine in winter as I can get the fridge to -15C but in summer on a hot night lucky to manage 0C.

What I propose to do is put CPU water blocks on the fridge and run cooled water or water/antifreeze through them. I was going to use a chest freezer to cool the coolant. This way I can get -20C in the fridge even in summer.

A better more elegant idea is to sandwich another Peltier between a water block and a CPU heatpipe cooler and use this to precool the coolant. Two of these will most probably be needed to get a suitable temperature drop. See the rough image two.

I will have to look at the cost and convenience of either method.

The chest freezer will have far more grunt. A 50% antifreeze water mixture is good for -37C. So in theory the Peltiers are only needed for fine contol of the temperature. The usual small chest freezer gets to about -18C. This means a camera fridge temperature of -30C is a doddle with this configuration.

It then occured to me all you extreme CPU cooling people may be interested.

The problem with Peltiers is if they are overloaded or fail you may lose your CPU.

If you insert a water block Peltier and CPU cooler sandwich in your coolant line just before your CPU the coolant will be below ambient.

If you want more cooling just add another.

With this configuration even if the Peltiers failed you still have your coolant at ambient due to the radiator.

Yes it is cloudy!


Bert