In astrophotography, this is actually the opposite of what you want to do. Generally you add cooling so that you can let your sensor run for longer, so you can

In astrophotography, this is actually the opposite of what you want to do. Generally you add cooling so that you can let your sensor run for longer, so you can collect more photons without increasing the noise appreciably. Image stacking can reduce noise afterwards, but there's no substitute for collecting more photons to increase the signal in an image... and the only way to do that is to try and clean up the noise floor (via cooling, better sensors, etc) :)