Re: Sterling engines for ships

On Fri, 24 Apr 2009 14:04:52 +0200, "Roger Conroy"
<rogerconroy.nospam@xxxxxxxxxxx> wrote:


"Andrew Robert Breen" <azb@xxxxxxxxxx> wrote in message
news:6qe8c6xgcv.ln2@xxxxxxxxxxxxxxxxxx
In article <gss07m$387$1@xxxxxxxxxxxxxxxxxxx>,
Roger Conroy <rogerconroy.nospam@xxxxxxxxxxx> wrote:

"Andrew Robert Breen" <azb@xxxxxxxxxx> wrote in message

Supervised a project on measuring the actual efficiency of a Stirling
engine a few years back: great fun.

So what was your conclusion - are they a worthwhile prime mover?

Our workshop-built engine turned out to be surprisingly efficient. Can't
remember the figures off-hand, but it was coming in at about 50% of its
theoretical (Carnot) efficiency, which certainly meant it'd beat any real
steam engine of its size and was probably competitive with a petrol engine
(it was a bit larger than the powerhead of a small outboard motor, and we
did consider trying to bodge it to the leg of a small Seagull motor at one
stage..). In the tests we were limited by how hot we could get the
electrical element we were using as the calibrated energy source - it
certainly produced much more power when heated with a propane burner. A
fully-engineered version using better materials (ceramics might be good in
places) would do a lot better. So yes, I reckon they are viable in more
general roles than they're currently used in - they could beat the best
diesels on efficiency, but they'd need a lot of engineering to get there
(just think on the time taken to develop the current generation of big
marine diesels...)

--
Andy Breen ~ Not speaking on behalf of the University of Wales,
Aberystwyth
Feng Shui: an ancient oriental art for extracting
money from the gullible (Martin Sinclair)

If one can run them on cheap (or even free) fuel they could really be one of
the major players in a post-oil world.
I once read a very positive article in a farming magazine about an
experimental engine in the ~100 kilowatt range fueled by wheat straw and
other agricultural trash burned in a firebox that looks like it came off an
old fashioned steam train engine, although the fuel is actually formed into
nodules and fed in automatically.


There was a flurry of research post-1973 oil crises but most of it
seems to have come to naught. I recall that Ford(?) or one of the big
US auto makers even had an experimental car with one in. Trouble is
they are big, slow accelerating and do not suit that sector of the car
market that needs an extension of personality rather than a means of
transportation - ie 99% of the market. IIRC the car had a radiator
about three times bigger than normal cars do.

A number of satellites use them - mainly as cooling machinery. A few
submarines have been fitted with them. Here and there stationary
pumps are powered by them. At one stage we had a couple at
waterholes/bores in the Kruger Park but I think all have been replaced
by solar powered pumps.

The popularity of the Sterling comes and goes. They have been around
for almost 2 centuries but have made little inroads into the power
production sector. Pity. I used to have a webpage, one of the first
IIRC, on Stirling engines. Back in the early nineties when the WWW
was just struggling to its feet!

Eugene L Griessel

Decisions of the judges will be final unless shouted down by a
really overwhelming majority of the crowd present. Abusive and
obscene language may not be used by contestants when addressing
members of the judging panel, or, conversely, by members of the
judging panel when addressing contestants (unless struck by a
boomerang).

- I post only from Sci.Military.Naval -
.

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