For something with erratic output like solar or wind it would make a lot of sense as you'll need a really big storage buffer to get output on demand plus you can reduce the capacity of your generator/elements to what you need at peak requirements instead of peak supply. That can be a big saving especially for wind as output rises exponentially with wind speed, a turbine that averages 2kw/h over the course of a year could potentially put out over 40 times that in gusty weather.
For situations like recovering heat from GPU's the heat output is more or less constant so there's no need for a large buffer if your trying to convert to electricity, the main thing limiting the output is the cost of the equipment due to exponentially diminishing returns the closer you get to ambient temperature, a heatsink at 20deg above ambient dissipates twice the energy of a heatsink 10deg above ambient which in turn dissipates twice the energy of one at 5deg over.
Yes, a hotter heatsink will dissipate more heat... because it's hotter...
The goal is to cool the chip... this means you move heat away from it... so you use a larger loop... for cooler block and better cooler of the cpu...
