"Martin Angove" wrote in message
...

1: If suntrackers are so efficient, why is it that the only one at the
Centre for Alternative Technology is about 25 years old? Why haven't
they installed more? Is it perhaps that the reflectors are a waste of
time?

Lots have happened in 25 years. Do a Goggle on sun trackers. There are
some off the shelf versions from the USA.

The point I think I was making was that they tend to get the best/most
efficient stuff at CAT eventually, and will try (almost) anything in the
meantime. Unless something's happened since I was last there, the only
sun tracker is this 25 year old thing. If they were so good (in this
climate perhaps) then *surely* CAT would have installed a couple more
up to date versions? I can understand how they might fractionally
increase the efficiency of a system where direct sunlight is the norm,
but where diffuse light is the norm (i.e. here) where do you aim your
device? On top of that you've the extra mechanicals to maintain, and the
extra energy required to cause the thing to track.

Some info:
Associated Press



1/13/2003 02:15 pm

A solar power demonstration program is making UNLV a hot spot for research
into tapping the sun in the southern Nevada desert as an alternative for the
nation's energy needs.

"UNLV is quickly becoming one of the leading solar researchers in the
country,"said Mary Jane Hale, a senior engineer for the National Renewable
Energy Lab in Golden, Colo."And then you have this great solar resource
there in southern Nevada."

UNLV researchers are trying to find an affordable way to generate energy
using the sun's power, and a parabolic dish array at the edge of the campus
helps to spotlight the program.

Two mirrored dishes track the sun, focusing light energy on a tube filled
with hydrogen gas that heats and drives the pistons of a Stirling engine.

The unit has been in operation for about a year. It produces 25 kilowatts of
power, or enough power for 250 100-watt lightbulbs, every second.

If testing is successful, the technology might justify the cost of putting
solar collectors on Bureau of Land Management property in the desert.

Sen. Harry Reid, D-Nev., helped secure $1 million in federal funds in 2002
for the UNLV research program. The University of Nevada, Reno got $1 million
of research money for geothermal energy.

However, the technology is expensive, and the nation has resisted
alternatives to fossil fuels.

Other solar technologies also are being tested, including a Duke Energy
project in Boulder City that uses oil, not hydrogen, to power the engine.

"What we have is a (presidential) administration right now that's not really
high on this kind of stuff,"said Bob Boehm, director of UNLV's Center for
Energy Research."They are high on oil."

The dishes soak up 30 percent of the sun's rays _ three times as much as
conventional solar panels. It would cost the average user triple the price
of traditional power sources, according to NREL officials.

But with continued research and use of the technology, costs are expected to
go down, officials said.

UNLV's renewable energy program is also training experts in a field where
there aren't many experts to go around, Boehm said.

The hope is that UNLV's projects will help make the state a Mecca not only
for the collection of energy but also the manufacturing of energy
collectors, Boehm said.

"It's not unreasonable that this could lead to some sort of industry
here,"he said."We are in a prime location for using the sun and
manufacturing these types of things."


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