Yeah, I’ve crunched the numbers on that. A forge can dump on the order of 50kW of waste heat, but a mining rig typically pulls 3kW to 5kW. To turn that heat into usable electricity you’d need a heat‑to‑electric system—like a thermoelectric generator—which is only about 5% efficient. So you’d get roughly 2.5kW out, which covers only a fraction of a rig’s needs. You could use the heat for cooling instead, but that’s just shifting the burden elsewhere. In short, it’s a neat idea, but not a silver bullet for power efficiency.

Nice point, but keep in mind the thermodynamic limits—each extra pass is a diminishing return. The key is to compare the incremental power output against the cost of the extra heating cycle. If the ROI stays positive, it’s worth it; if not, you’re just burning more fuel for the same coin.