IMM,
Just a quickie, because this is turning into one of your religious-type
arguments, but

a: the sun tracker you mention is in NEVADA, for Pete's sake, not
NEASDEN! We *started* by discussing domestic scale arrangements in this
country. It needs DIRECT sunlight to work, hence their suggestion of it
being useful in the desert. All large reflector-arrays I've seen to date
have been in similar situations. It is very hard to focus a completely
diffuse source, which is what the sun is throughout most of the year in
this country. Even on only partly cloudy days you begin to reduce
efficiency dramatically. There are other technologies which are much
more suited to Britain's climate.

b: it is on a very large scale (25kW), when compared with domestic use
(and what kind of journalistic rubbish is "25kW per second"?)

c: it involves high pressure hot gasses and doesn't look like something
which could be scaled down any time soon.

d: I'm not convinced that an unsealed Stirling engine is really a
Stirling engine. It sounds more like a conventional high pressure steam
engine. Incidentally, are we actually talking about steam pressure
cylinders, or steam turbines when referring to "normal" steam engines?

e: when you say that "virtually all" Stirlings have a piston in cylinder
arrangement, I presume you are referring to an "expansion" cylinder
somehow attached to the main cylinder which contains the bulk of the
working fluid and the displacement piston? This is an interesting
compromise and the calculations as to dimensions of this extra cylinder
will have to be made very carefully in order to allow maximum heating
and cooling of the working fluid which is common to it and the main
cylinder.

f: are you aware that the fuel consumption and emmissions figures for
Renault's dCi Diesel High Pressure Common Rail engines actually *better*
those of Toyota's so-called "green" hybrid car? Ok, it was in a Renault
brochure I read this, but it's scary. (We have a large - 1.9l - Renault
dCi and it's fantastic. Last time I did the 400 mile round trip to see
the parents I averaged 61mpg, and I wasn't trying *very* hard to be
economical. The 1.9l dCi Scenic out-accellerates our 1.6l 16V Laguna
too).

Hwyl!

M.

--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
.... If we don't succeed, we run the risk of failure