Solar Stirling Engine-better than silicon chips?

 Robert Stirling invented a heat engine in 1816... it can use focused
sunlight to move pistons by expansion and contraction of a gas...
driving an electricity generator...
Giant power plant for Southern California Edison now under
construction.
read more:
http://gregvanderlaan.com/solar.aspx

Schatz Energy Labs at Humboldt State University does research into
hydrogen fuel cells... basically, a better battery...
read more:
http://gregvanderlaan.com/ecofair.aspx

  gregvan wrote:

As I understand it, stirling engines get less efficient the smaller
they are and suffer from high maintenance and mechanical breakdowns.

Solar cells (including silicon chips) work just as well at both
small and large scales and don't have moving parts, friction or
need for practically any maintenance.

Steam engines also seem more popular for large scale power generation.

Anthony

 Anthony Matonak wrote:

A commercial power plant wouldn't be "smaller" and I suspect that the
maintenance and breakdown are functions of design rather than anything
innate.  If Mazda can make Wankels reliable .  .  .


All else (including efficiency) being equal, what do they cost for a
large plant?


Steam is a well established technology but it has its own
problems--the main reason that it's reliable is that they've been
working on it for going on 200 years now.

Stirlings and fuel cells may have been big news in the '60s, but I'm a
bit puzzled as to why anyone thinks that they're anything to get
excited about today.


--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

 Stirlings are an excellent form of heat transfer engine being
completely agnostic as to the source of the heat which can be waste,
generated, solar, whatever.  They're highly reliable, having few
moving parts, and very low maintenance.  They're quiet, and are
consequently currently used in a number of non-nuclear military
submarines, and they're very easy to build.  They've also been
successfully used to power torpedoes and NASA have them as a power
source for future very deep space missions.

But... like anything they have drawbacks.  Stirlings work on
temperature difference.  The greater the difference the more efficient
the engine.  People get excited about using them to convert heat into
mechanical (and thus electric) energy without considering that the
cold side of the engine is just as important.  This is a key weakness
in many Stirling installations where there is plenty of heat available
but the cooling side may be limited.  They can be slow to start and
varying the power output takes time.  Their theoretical efficiency is
very high, practically, rather less so.

That said, Stirlings are much more efficient than, say, internal
combustion engines.  If you've got an application where you're not
that fussed that it can take a while to heat it up to start, and you
don't mind that there's a considerable lag between turning up the heat
and getting increased power output then Stirlings are great.  Phillips
produced a Stirling generator in the 1960s which was way cheaper to
run than conventional models but fuel price wasn't a great driver back
then.  Most of the auto makers also researched one but no-one to my
knowledge got a starting time of under 3 minutes which was reckoned to
be more than the public would stand for.... and you need a way of
controling the output.  Otto cycles were inefficient but very easy to
run.

Solar to Stirling energy is potentially an excellent way of converting
solar heat to electricity at a considerably higher efficiency than any
other existing technology.  The downside is the limited availability
of sites with reliable sun /and/ reliable cooling.

Evan

 evan@murray-jones.net wrote:


Fascinating. Aren't most generators real fuel hogs?


   Most of the auto makers also researched one but no-one to my

   I've wondered if anyone is working on a Sterling Hybrid. The be all
reason for hybrids is their fuel efficiency. I see that electric motor
technology is there for the power requirements in a small space. You'd
need enough battery storage for the time lag in starting and power changes.


It seems to me that with the coming fuel squeeze, that efficiency should
be a primary concern and not just for solar applications. Is there much
efficency difference between a turbine and sterling at the same
temperature delta? And how much larger is the sterling?


  The downside is the limited availability

   That would be a problem with any heat engine. Where I live the
largest water users are the power companies, for cooling. I suppose that
is one of the reasons for the extreme heights of solar chimneys, for the
temperature gradient.

   Jeff