1979 NASA Stirling-powered AMC Spirit - photo

**Altair** · Dec 1, 2021, 07:07 AM

Stirling-powered AMC Spirit developed by NASA and the United States Department of Energy following the oil crises of the 1970s.

Fullsize image: https://diqn32j8nouaz.cloudfront.net...t_fullsize.jpg

Previously:

Napier Deltic engine gearbox - photo
Napier Deltic engine triangular cylinder arrangement - photos
Napier Deltic locomotive engine - photo

**BuffaloJohn** · Dec 2, 2021, 11:28 AM

According to the interwebs, it appears this car had a 28.5 mpg test along with a 26 to 36 second acceleration (guessing zero to 60).

**mwmkravchenko** · Dec 5, 2021, 03:54 PM

https://en.wikipedia.org/wiki/Applic...tirling_engine

Seems like there were at least two versions designed to run vehicles via Sterling cycle engines. The second one was rather spectacular in mileage for the time. Actually pretty decent in our time to for the size of vehicle.

These Sterling engines have a lot of potential. Used on some of the quietest submarines on the planet. So they are a mature design.

**nova_robotics** · Dec 5, 2021, 07:45 PM

Originally Posted by mwmkravchenko

These Sterling engines have a lot of potential. Used on some of the quietest submarines on the planet. So they are a mature design.

I watched a documentary about those Swedish Gotland-class submarines. Very interesting stuff. My patent guy is in love with Sterling engines. I got him a small toy one a few years ago. I hope we see a proliferation of Sterling engines in the near future. They allow useful work to be extracted from a multitude of heat sources that would otherwise be useless. There are a ton of applications for that, particularly with the current huge push toward renewables and green technologies.

Also interesting are ORCs (organic rankine cycle generators). There are a number of manufacturers making these now. They are skid mounted self contained units that allow electricity production from waste heat sources.

**mwmkravchenko** · Dec 5, 2021, 08:07 PM

Interesting! I had never heard of this until you posted it. Again something that make to much sense for it to happen.

All that really has to happen is oil and it's derivatives to be priced as it actually costs each country in subsidies and true losses due to the effects of the oil , gas, or coal's use. I just watched an interesting video that quotes the IPCC as pricing that true cost at over 8 trillion/year by 2025. That is a lot of money. Fifty percent of the U.S. GDP. That tacking on the true cost to fossil fuels world wide just might make all these waste to power concepts a reality if a little R&D money plus scale manufacturing was put into them,.

**mwmkravchenko** · Dec 5, 2021, 08:13 PM

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.

**nova_robotics** · Dec 5, 2021, 09:51 PM

Originally Posted by mwmkravchenko

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.

**mwmkravchenko** · Dec 6, 2021, 09:59 AM

Originally Posted by nova_robotics

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.

I never think of Power Factor as a problem. I don't work in commercial scale electricity. But I understand what you are saying. It truly makes sense to use an active means of correcting Power Factor. Using co-generation versus simply a static method that balances the load only under specific conditions is a no brainer. Especially when there is literally a payback on the installation! That was my biggest take away from that little report. It pays to do this properly.