Completed the Phase Two prototype today and ran a test. Phase Two involves the new carbon fibre bracket, the replacement of the heatsink/fan that came with the TEC, with a CPU Heat Pipe Cooler (Deepcool Gammaxx 200). This cooler has a slightly smaller fan (92mm vs 100mm) but with sintered copper pipes it is going more efficient; it also weighs about the same as the original. I picked the sintered copper pipe cooler as it performs much better at all angles than wick or grooved heat pipes. I found a good article online that compares the performance of different heat pipe types and the effects of orientation (relation to gravity) on performance, it is worth a read if your interested, as telescopes slew and rotate so orientation is changing. Link is here:
https://www.enertron-inc.com/pdf/res...ientations.pdf
I also tried out the argon bag idea.
So from a room ambient of 22.1C the sensor temperature quickly dropped to 0C and kept going right to -3C, which is a delta T of 25C - which is a good improvement over my Phase One system that achieved a delta T of 17C.
On a nice cool night this system should be able to get down below -10C easily. Considering that I had no insulation on the cold finger outside the camera other than the Plastidip Rubber spray, I am pretty pleased with that performance, the finger iced up pretty good. Have to put it down to the much better heatsink/fan combo. It also has no vibration transfer from the fan to the camera. There was no moisture apparent in the bag, which I had filled with argon, so no fogging, no condensation inside, etc. it looks terrible but it works ok and all camera functions and controls work fine. I used my AC adaptor for camera power so battery change will not be an issue, but consider that if your thinking of bagging the camera; you don't want to be opening it up to change the battery unless your prepared to refill the argon.
Photos are attached.
I am tempted to buy one of the high performance single stage TECs from the US to see how far I can push single stage cooling while still staying within the limits of my controller power.
