Quote:
Originally Posted by Malewithatail
Yes, as close to absolute zero as possible to reduce thermal noise as low as possible. Multiple, stacked pielter devices, commercially available from dead car/fridge/freezers, can be stacked one behind the other and are quite capable of getting to within a bugs whisker of absolute zero, or -273 degrees.
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I am not sure of your calculations but Peltier devices are non-linear, they are primarily designed to work more efficient in high heat until thermal runaway takes hold but their efficiency falls dramatically at about -50 degrees C. After that point the molecules in the semiconductor region delta T bottoms out at 2 degrees per Peltier module.
I have an experiment on my bench now using up to 3 Peltier devices and I can already see from my results that it will get nowhere near the level of cooling.
The lowest I have ever seen it go is when using an ethanol mix radiator where the Peltier device is cooling the liquid in the radiator to about -100 degrees but it would be impractical for astrophotography as the camera would fail the function.
The same would apply to most electronic devices as most are rated to only work down to -40 to -70 for consumer applications. Industrial down to -100, space-based are specially made to withstand the harsh environment.
Already with 2 devices, I get a DT of 50 degrees on an open bench environment. I expect I will get a DT of up to 70 after placing it in an enclosure which is my next task.
Anyway, good luck with getting down that low.