1979 NASA Stirling-powered AMC Spirit - photo

[nova_robotics]

https://www.tmeic.com/Repository/Med...lik_ORC_v9.pdf

Well what do you know. An industry that is actually implementing something that is truly win-win. It's steel making. Add in cement making too enormous amounts of waste heat available. Foundries, there are other heat intensive industries but they escape me at the moment.

Nice to see that this can work in the real world.

Most industrial plants have to reject tons of heat, either through cooling towers or big radiators. Might as well install an ORC and generate a bunch of electricity from what would just normally go to waste. I do a lot of work in OSB, and they have absolutely massive furnaces which ultimately dump a ton of waste heat to the atmosphere. It's just like throwing money out the window. That's where I first encountered ORCs about 10 years ago. We tried to sell the client on the idea, and it was new and scary so they didn't do it.

The PDF you linked is actually a bit of a crappy ORC. The newer synchronous generator based ORCs are much better. At first the engineers were a bit brainless with their ORC design and just tried to make them efficient as possible, which means adding power factor correction capacitors to the machine to try to achieve as close as possible to a power factor of 1. Usually real world above 0.9, which is very good. Very little reactive power, which at first glance is what you should want.

...but what ends up happening is if you subtract a whole bunch of real power by generating it on site you're left with the same amount of reactive power, you crank your power factor all out of whack, which causes the power company to freak out and penalize you. Most plants are billed on total power used (kWh), maximum peak recorded power (kW), and power factor. Large capacitor banks are installed to counteract lagging power factor caused by induction motors (most plants have lagging power factors). Capacitors have the opposite effect, bringing the plant's power factor close enough to 1 that the power company won't penalize them. So the newer smarter ORCs can intentionally make their power factor really bad, but bad in the opposite direction of how your plant is bad, just like a capacitor.

So a well thought out ORC can not only generate electricity, it can also duplicate the function of a capacitor bank in the process, largely making them unnecessary. Most plants spend big CapEx money on installing capacitor banks. Why not put that money towards something more useful? It just makes all kinds of sense to install an ORC. But clients are dumb and reactionary, so you don't see them very often.