DIY Turbosteamer?

[Maillemann]

So I'm sure you've all heard of or seen the BMW Turbosteamer concept. Not really a new idea of course, but BMW being the "pioneer" in the field they are still a decade away from production.

What I'm wondering is... can an A/C compressor be run off a flow of steam, in effect, operating it in reverse? As I understand it, auto A/C compressors are of a reciprocating piston design, so I would think it is perhaps feasible. If so, then don't A/C equipped vehicles already have most of the plumbing and hardware required for a homebuilt "turbosteamer" arrangement?

Would it be feasible to install a heat exchanger around the cat, run a closed-loop system utilizing the existing condenser, etc., and add a few HP to the crank? I have almost no technical knowledge of the A/C system and also do not have a good understanding of how such input would be handled by the variable of crank/pulley speed and power.

Just an idea. Thoughts?

[JanGeo]

Newer A/C compressors use a variable vane compressor and will not run backwards. Older ones if fed steem would have corrosion problems and the amount of energy available from boiling water is somewhat limited from the exhost when it comes to boiling water at a high temperature and pressure although a high speed sterling engine connected to an alternator may provide more useful energy back into the electrical system. you have to look at the total energy available at the exhost in the form of heat relative to the percent of the fuel burned not producing power and heat in the engine and then you can get an idea as to how much energy is available in the exhost for conversion, then factor in the thermal conversion efficiency of the system that will be added and see if it yields anything substantial to even bother with trying it.

[Sludgy]

I've long thought about using a steam cycle to make car engines more efficient, but there are big problems:

1) Freezing. Steam engines use water, not antifreeze.
2) You need a (big) condenser to avoid carrying 1000 pounds of water around.
3) Steam engines run al low speed (<1000 rpm) whereas gas engines go to 6000 or more. How do you gear them up?

There are lots more problems, but these are among the biggest.

[The Toecutter]

BMW is basically pinching off a big fat steamer onto the public with this complicated and apparently unreliable concept. It should make an EV.

[ELF]

I wonder what happens to emissions? If they take all the heat out of the exhaust how does the cat. work?
I do like the idea of trying to find a way use some of the energy lost as heat.

[omgwtfbyobbq]

It'd probably be easier to retrofit a MPFI engine for gasoline operation/TBI and add another cycle for water injection to take advantage of the waste heat. I've heard that emulsification of the oil can be a problem, so this may not be viable.

[thecrxproject]

I am new to this forum but have told many about this on others... I am doing a research project on waste heat recovery on my 1991 Honda CRX, somewhat similar to the BMW turbosteamer concept. There are many more complexities and feats of engineering that allow the BMW turbosteamer to recover such a significant amount of power from wasted heat. Waste heat recovery is by no means a new concept, as said earlier, but neither are electric cars, fuel cells, etc (All 30+ year old technology). I would not recommend taking this project on as a DIYer without a large amount of resources. I have been working on this idea for about 6 months now, working out the kinks, etc, and it not even close to being finished..

So to clarify and add some to the things said earlier...
-the Cat should have no problem being hot enough for operation if the system is designed correctly. I am planning on determining whether or not regulated steam injection into the pre-cat exhaust will decrease emissions as well, but it is well known that air injection into the exhaust helps burn unburnt hydrocarbons and reduces emissions.
-steam engines are infact extremely reliable and would probably be more of a common-sight had many inventors not been bought out, or unfortunate mishaps. Think of the advancements that could have been made had the steam engine persisted and the ICE did not...
-Steam engines, or more well put - Rankine Cycle engines, can run off multiple working fluids, including freon for example, steam is just usually reffered to when boiling water. The BMW system actually has another working fluid in addition to water (forgot what it was at the moment)..

So the big question is why bother right?
Well I like to think that if developed right, there could be waste heat recovery systems designed to simply bolt on to an older vehicle and increase fuel economy and decrease emissions. Why scrap a perfectly good car when you can just bring it up to standards by merely modifying it?

[cfg83]

thecrxproject -

Originally Posted by thecrxproject

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So the big question is why bother right?
Well I like to think that if developed right, there could be waste heat recovery systems designed to simply bolt on to an older vehicle and increase fuel economy and decrease emissions. Why scrap a perfectly good car when you can just bring it up to standards by merely modifying it?

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