I took that to mean something more like "in cases where we already exhaust waste heat, you could reclaim some of that energy". That does seem doable, my refrige

I took that to mean something more like "in cases where we already exhaust waste heat, you could reclaim some of that energy". That does seem doable, my refrigerator is a little heat pump in reverse, why not stick a Peltier on the coils on the back and charge a battery to run LEDs to light the inside?