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Old 26-11-2009, 11:03 AM
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Scorpius51 (John)
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Scorpius51 is offline
 
Join Date: Sep 2009
Location: Canberra
Posts: 394
Hi Leon

Good to see you've got it going.

I noticed the amount of frost on the cold plate. I don't know how you propose to attach your camera to the Peltier, but it would be a good idea to avoid the frost buildup, as it adds significantly to the thermal load. Also, 15 mins seems a long time for the cooling to happen - in my experience 15 seconds would be closer to the mark!

You do mention that you will be enclosing it in a chamber. What I have done with a Peltier-cooled photodetector that I have been involved with, is to hermetically enclose the Peltier/detector unit with an activated desiccant sachet, or a molecular sieve (http://en.wikipedia.org/wiki/Molecular_sieve), to remove the water vapour. Additionally, if you have access to dry Nitrogen, then flush the chamber with this first before sealing off. You can easily gain up to 5-10 (or more) degrees doing this - even without the N2 flush.

You mention that the cold face was at 16C and the ambient was 32C - it would be a good idea the get the temperature of the heatsink at the hot side of the Peltier. This will allow you to determine the temperature differential of the Peltier unit. The dT should be at least 40 degrees or more (50-60C, depending on the Peltier type) when the optimum power is applied.

You may also benefit from a shroud around part of the heatsink, on the fin side, to concentrate the air flow over the fins.

Good luck
John
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