Well the math is correct, the methodology has obvious flaws some of which I pointed out. If you took all the energy that has been released by humanity burning things since the industrial revolution and dumped it into a closed system consisting of just the atmosphere, it would rise by about 1.5 C.
The discussion thread (and original question) you are participating in is about heat being rejected to the atmosphere through vapor-compression refrigeration or evaporative cooling, not CO2 or emissions from combustion. Reread the top level comment.
The amount of heat rejected to the atmosphere from electronic devices is negligible.
