Quote:
Originally Posted by LewisM
I reversed the fan to extract instead of blowing.
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I think that is a significant part of your problem.
In order for your peltier device to cool effectively you need to keep the hot side as cool as possible (as its the temperature differential between the hot side and the cold side that is important). If you let the hot side get really hot, to say 50C, then the cold side isn't going to be much different than the ambient temperature. So this doesnt happen, you need to ideally transfer heat away from the hot side of the peltier to the outside ambient at least as fast as the heat flow across the peltier itself. To achieve this means that your hot side heat sink and fan need to be operating as efficiently as possible.
Now, a centrifugal device like a fan is much more efficient at generating a positive pressure differential (ie increasing the pressure on the discharge side by blowing) than it is a negative pressure (reducing pressure on the inlet side - sucking). It's just like a centrifugal pump. By setting up your fan to suck instead of blow as you have done, it would seem that the air movement is simply not enough to disperse the heat fast enough.
The take home message - get it to blow across your heat sink instead of sucking from it.
Incidently, I have been thinking about building a DIY peltier cooler for my DSLR as well, and have sourced a peltier and power supply. One idea that I have had (to save weight hanging off my focuser) was to use water cooling instead of a heatsink and fan. I was thinking a CPU water cooling block with tubing connected to an aquarium pump and a reservoir of cold/ice water. Haven't tried it out yet but it should in theory be much more efficient than an air cooled setup.
