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there's no proof the heat can be utilized efficiently
Yes. It is basics of physics.Quote
other than heating the facility in winter
and this is not "work" in terms of "proof-of-work"Quote
Also even if the heat is 100% efficiently utilized
Perpetuum Mobile? 
Again? Oh, no!Bullshit, the energy being there doesn't mean it can be easily 100% efficiently utilized. Try convert sunlight into electricity with 100% efficiency? or build a simple household boiler with 100% efficiency?
In terms of heating the facility, it's usually a facility that doesn't need heating, most likely it needs cooling. Also it works only in winter.