[V8] solar steam engine

[Mike Arman]

>
> Now - to go even further off track, I got interested in trying to make a solar powered
> (stationary) steam engine.  Don't ask why - if anyone in the world understands the "why" part, it
> would be this list, I am just curious if a say a parabolic mirror on your roof could make enough
> steam to power a small piston type engine?  The idea is to make enough power to turn a generator
> large enough to run a home air conditioner.  I think 5000 watts would be plenty for a large
> house.The obvious benefit is the hotter it gets, the better your air conditioner works.  The
> obvious downside is superheated steam under pressure makes an excellent skin remover, and the
> neighbors will get pissy if they find boiler parts blown into their yards.  Those are the two
> negatives I hear the most.
>
> And since this is an Audi forum, I would of course park my Audi in the garage of such a home...


Build the steam engine first. I had a very similar idea for a steam engine powered emergency 
generator, but a friend of mine, who knows quite a bit about steam engines and has owned/built 
several talked me out of it.

Here's the problem - steam engines are surly, uncooperative, dirty, dangerous devices and CANNOT be 
left unattended like an electric motor. Even with a safety valve (and don't even THINK about running 
one with out a safety valve) boiler explosions are not that rare, and as you point out, scatter hot 
shrapnel far and wide - live steam is some nasty stuff, too. People get killed at live steam tractor 
meets, and this is despite expert operators and comprehensive safety procedures.



5000 watts is 6.7 hp (746 watts = 1 hp) so you'll probably need an 8 to 10 hp steam engine to run 
the generator. There are two flavors of generator power heads, the cheap ones run at 3,600 rpm, the 
good ones run at 1,800 rpm and are much more expensive and durable (also harder to find).

5KW will *run* a room air conditioner, but may not *start* it. Further, if the power fails for a 
moment, 5KW definitely will NOT re-start it, and you'll be blowing a lot of fuses. (The A/C pressure 
has to bleed down a minute or two or the starting load is considerably higher.)


This approach is too convoluted even though the power source (the sun) is free. We are going from 
heat to steam to rotation to a generator to electricity to a motor to a compressor to squeeze the 
freon . . . lots of moving parts to get out of adjustment, break down, and some of them are too 
dangerous to have around.


Caveat - I have NOT tried this, but here are my thoughts on the subject. You may or may not want to 
try this at home, and one thing I can promise you is that YMMV. Also, if it blows up, you will own 
all the pieces, and it isn't my fault. Ready?


Lets simplicate things a bit . . . I once had a very old window air conditioner that had a separate 
electric motor and compressor. Modern (anything built after probably 1965) air conditioners have 
combined motor/compressor units. The newer units are much more efficient, and that is important if 
we are paying for the power - but with this one, we are not!

Visit a junkyard and strip out an automotive air conditioner. Get one that uses R-134 because the 
older R-12 freon is really expensive and you need some kind of license to buy it (you can get the 
license on line, it isn't expensive, but hey, do we need this added complexity?

Instead of building a steam engine which will run on steam created by the solar reflector, build a 
Sterling engine instead. There are plenty of plans floating around the internet, I seem to recall 
that some of these things will make 10 hp. The hot side of the Sterling engine is powered by the 
sun, the cold side is cooled by a water jacket and radiator (or through some garden hoses connected 
to your swimming pool or other water reservoir).

Couple the output of the Sterling engine to the A/C compressor you scavenged from the junkyard, 
charge the system, and enjoy the cool.

There's no steam, no smoke, no exhaust, no boiler, and almost no noise. Sterling engines are simple 
and durable. We've dispensed with the conversion to electricity because what we REALLY needed was 
something that rotates to drive the A/C compressor, and the Sterling engine will do that - although 
you'll need to gear it up some, Sterling engines are not fast. You will want a 12 volt battery to 
run the A/C fan, or you can add an automotive alternator to the system with just a few belts and 
pulleys.

Howzat? Thinking this will keep someone off the streets and out of trouble for a little while AND it 
is safe to park your Audi next to it! Let me know how you do . . .

Best Regards,

Mike Arman
90V8Q