Exhaust Heat Recovery - Steam Power

[Christ]

Originally Posted by ConnClark

Yes they do. Conventional turbines operate on the defection of mass. A Tesla turbine relies on cohesion of the air sticking to the rotors. A sudden change in supply flow or load breaks this cohesion and generates turbulence that drops its efficiency.

Adding to this, the Tesla turbine's spacing between discs needs to be optimized for the density of the fluid which is used to impart energy to it.

Obviously, steam of varying temperature/pressure will also be of varying density, and thusly, the turbine probably won't reach a point where it's efficiency is ever maximized to any large extent, or for any large period of time.

A Tesla turbine would probably be better suited in the coolant flow, where temperatures don't vary much, and pressure is basically constant once operating temps are reached.

[ConnClark]

I just realized I already have a turbine. All I need for a one pass system is to install a water tank that feeds water to some thin piping that wraps around my exhaust starting at the bottom of the down pipe and ends just after the turbo. I then take the other end and feed it into my exhaust manifold.

Since I have a diesel any steam generated increases my boost which in turn increases my engine efficiency.

[Christ]

Originally Posted by ConnClark

I just realized I already have a turbine. All I need for a one pass system is to install a water tank that feeds water to some thin piping that wraps around my exhaust starting at the bottom of the down pipe and ends just after the turbo. I then take the other end and feed it into my exhaust manifold.

Since I have a diesel any steam generated increases my boost which in turn increases my engine efficiency.

Bonus points!

Even more bonus points if you can make the feed line dump using only the pressure generated by heating the container!

[Daox]

I'd imagine that might work alright. However, if you inject too much steam you'll reduce your efficiency though. I have no idea where that limit might be though.

[ConnClark]

Originally Posted by Christ

Bonus points!

Even more bonus points if you can make the feed line dump using only the pressure generated by heating the container!

That is easy just make the feed container a pressure vessel and use gravity feed. As long as the container's water is level is below the manifold you can have a feed back line to it. see the attached picture. The pressure of the vessel will never exceed the pressure of my manifold. As long as it will hold at 70 psi I'll be fine.

Originally Posted by Daox

I'd imagine that might work alright. However, if you inject too much steam you'll reduce your efficiency though. I have no idea where that limit might be though.

I imaging that point would be more than I would ever run because I would have to top of the feed tank too often.

[Christ]

I like this idea. I'd like to see it have it's own thread and some followups.

[ConnClark]

to expand on it further you could add Isopropyl alcohol or methanol to the mix and get freeze protection plus an added boost from the fuel value for more performance

[Piwoslaw]

Originally Posted by Christ

I like this idea. I'd like to see it have it's own thread and some followups.

I second that.

[4ringcircus]

Wow, great thread. Are we missing some electrical concepts here: You don't need the steam engine to produce enough power to completely power up an alternator. Why couldn't we just hook up the alternator in series prior to the original alternator. In so doing, it would send electricity to the second alternator, thus reducing the load. Heck, at any moment if the steam engine alternator produces more current than the draw of the car, wouldn't the original alternator work like motor itself and improve FE even more? ~ Or would this just burn up the original altnernator?

[IamIan]

Originally Posted by C3H8

i hate to be a doubter, however you would be better off pointing some little steam nozzle out the back of the car and using it for its tiny thrust output. that way the energy could be used to do something directly instead of using it to spin a shaft, which has air drag, and bearing drag, and converting mechanical energy to electrical via a 3 phase alternator, which then converts 3 phase a/c into dc, etc etc.

I like it ... less complex ... fewer conversion steps and losses ... and directly pushes the car.

The bad news ... you will likely quickly vent a considerable amount of water ... which means you have to carry with you that much water ... which is a weight penalty.

However ... One example of what has been achievable ... A Steam powered 'rocket' produced ~1,333 Pounds of trust for ~6 seconds from 200 pounds of steam ... the weight is the same liquid water or stream ... the volume changes.

Primary Propulsion

~200 pounds of liquid water would be ~24 Gallons of water ... or a scale of ~333 Pounds of thrust per second per gallon of water vented as steam ... assuming equal efficiency / performance could be achieved from an automotive waste heat exhaust steam jet engine... it might be able to be improved ... but at least that is an example of what has been achieved.

Ideally nothing is put in directly in the exhaust stream ... just the heat is used on the outside of the exhaust pipe .... thus extremely little back pressure ... only the small amount caused by extracting heat from the exhaust gasses... just enough water to feed the steam jet.

However some of the other options being discussed ... while maybe less efficient and maybe more complex ... they do have the potential of eventually being turned into a closed system ... which would mean a fixed amount of water / working fluid is used ... and would not need to have more refilled or added regularly ... which would be a negative of the automotive exhaust waste heat steam jet engine... AEWHSJE ??? I need a different acronym.