Alternative Power sources - solar trough for electricity

Author

solar trough for electricity

peter E

2005-07-24, 9:06 pm

Hi all,

I am completely knew to this field.

I was wondering of the costs of parabolic trough solar collectors for
electricity generation in developing countires.

My best guess was an oil filled tube system running to a tank that
provides steam which in turn powers a generator. For storage envision
water reserviors at differing heights.

Does anyone know which companies provide complete systems, and the
price of. Parabolic dish and stirling engine generators appear to cost
into the hundreds of thousands and thus do not bear thinking about. PV
cells seem quite expensive in initial outlay but do have the advantage
of low maintneance.

Links to relevant websites would be appreciated.

Regards, N. Peter Evans

peter E

2005-07-24, 9:06 pm

after having a small look at other posts I can see that parabolic
dishes seem an option, especially as angle controllers cost $35.
Trough, or parabolic dish I do not care, whichever is cheapest.

If the tube is filled with air and that in turns runs an air motor, is
that cheaper ansdsimpler, if not as effecient?

Surely this sort of thing must have been dozens of times and there
ought to be an off the shelf sytem that can be purchased.

N. Peter Evans

SQLit

2005-07-24, 9:06 pm

"peter E" <nicholas.evans@students.vu.edu.au> wrote in message
news:1122085494.771732.197930@g49g2000cwa.googlegroups.com...
> after having a small look at other posts I can see that parabolic
> dishes seem an option, especially as angle controllers cost $35.
> Trough, or parabolic dish I do not care, whichever is cheapest.
>
> If the tube is filled with air and that in turns runs an air motor, is
> that cheaper ansdsimpler, if not as effecient?
>
> Surely this sort of thing must have been dozens of times and there
> ought to be an off the shelf sytem that can be purchased.
>
> N. Peter Evans

Arizona Public Service runs a solar research site in Tempe Az.
They are using sterling motors during the day and natural gas at night. I
believe that the cost for each "sun flower" is over a million dollars and it
produces 25 kw
http://www.aps.com/my_community/Solar/Solar_6.html
Check out the pages

Your intentions seem pure. But there is no easy/cheap way to do what your
describing. Some simple research on Horsepower and its conversion from
different sources is all that you need to do.

As an example
Have you ever wondered why pressure washers that are commonly sold are with
gas engines? The size and cost of electric motors makes them more expensive
than their gas counter parts.
Believe me I have tried to figure out how to do it cause I would prefer not
to have another motor to take care of. Sure you can get little electric
pressure washers with ~2000 psi, but the gallons are not there.

Please post your links to the "air motor" If it does not use compressed air
I would be interested.

Every time you exchange energy you loose some. Example ---- solar----
PV----- inverter----- battery----- load. Losses can reach close to 50%.

peter E

2005-07-24, 9:06 pm

hi all,

have spent all day looking into this topic and have learnt a lot

have come across an excellent website into alternative power, seems
very much based around the practical, like how do I build such a
turbine, etc.

Site is http://www.fieldlines.com/

It had a lot of practical stuff too, like someone that built a 6' wind
turbine for $100. When you compare the $3000 that a commercial one can
cost you can see that building one from junk is often worth it.

When I looked into trough power, saw that only about 9 or so in
commercial operation in the whole world, against mor than 40000 PV
solar projects.

The trough people are doing some research with direct steam, in that
the tube is filled with water, whcih is heated and the steam that comes
off goes directly into a steam engine.

I have read about cheaper construction techniques in using mylar film
from home depot streched between 2 plywood parabolic formers, how cost
effective this is I do not know.

Yes the big stirling-dish setups cost a huge amount of money

By air motor I meant that the motor was run by compressed air, and the
air is compressed by heat from the sun. But on thinking about this
doubt it would work well, at 300C air would at 570K about twice normal
air temp of 290K, thus at 300C its pressure would only be 2 bar.

>From a commercial large scale set up it seems that trough power is
almost there, very close to being economic. I jsut wonder if the home
tinkerer say in a village in some small country would be able to come
up with. Seems that it would have to be large area to provide anything
of use, 10 square meters of area at least. If there happened to be a
steam engine lying around may be an economic project,,, but who happens
to have a steam engine lying around. Yes PV is much simpler.

Yes you are right about each exchange losing energy.

One advantage of the engine driving a pump directly is that no
batteries are required, just use the height difference of two small
dams. In developing countires the ability to make two small dams is
often easier than spending thousands of dollars on lead acid battery
storage.

with home power, if off grid is often better to go completely DC,
Lights work fine with DC. Many household appliacnces use transformers
inside them to convert AC currect to DC to power their motors. You can
buy DC powered fridges. do not know about TV's

home made trough power systems do not seem economic

Regards, N. Peter Evans

Bill Kaszeta / Photovoltaic Resources

2005-07-25, 1:21 am

On 22 Jul 2005 19:09:42 -0700, "peter E" <nicholas.evans@students.vu.edu.au> wrote:

>Hi all,
>
>I am completely knew to this field.
>
>I was wondering of the costs of parabolic trough solar collectors for
>electricity generation in developing countires.
>
>My best guess was an oil filled tube system running to a tank that
>provides steam which in turn powers a generator. For storage envision
>water reserviors at differing heights.
>
>Does anyone know which companies provide complete systems, and the
>price of. Parabolic dish and stirling engine generators appear to cost
>into the hundreds of thousands and thus do not bear thinking about. PV
>cells seem quite expensive in initial outlay but do have the advantage
>of low maintneance.
>
>Links to relevant websites would be appreciated.
>
>Regards, N. Peter Evans
>

This idea has been tried and found in accordance with
the following question/answer:

Q: How do you make a small fortune in solar energy?

A: Start with a large fortune!

Bill Kaszeta
Photovoltaic Resources Int'l
Tempe Arizona USA
bill@pvri-removethis.biz

peter E

2005-07-25, 11:21 pm

have looked into this a bit more and found 20hp steam engines for $6500
and 3hp for $2500. They are made my a one man band in America. I
suspect that India would be the place to find them cheaply, but it is a
real chore to search for information there.

Not many businesses seem to have websites and their yellow pages site
is a mess. Steam power also requires water and maintenace.

At this point PV still seems a better solar way to go that parabolic
troughs and boilers. I did work out how to make the troughs cheaply
using mylar film and some simple jigs and chipboard, but still seems
dead idea at this stage

Junk alternator converted to DC . mylar and chipboard troughs, indian
made steam engine... no it just is not working, cost would still be
over $1000 for a 100W system, best off using PV cells. Maybe if scaled
up to 10kW might go OK,, say using 100 sqr meters of trough area to
power a village... hmm maybe.. maybe. Still not looking good though. A
ballpark figure of 10kW for $10000 may be reasonable, but have no idea
if it could be done for this price. A lot more maintenance than PV...
but in developing countires labuor is cheap, $1 a day. Still looks like
going nowhere though.

10kW PV costs 80000? a lot of power.. how much cost to make 100sqr
meters of parabolic troughs? fair bit..

When commerical operators say they cannot yet compete with coal fired
power stations is thus uneconomic. But if the competition if for
off-grid systems does it have a chance? here the competition is PV
cells. At larger scales troughs seem competitive to PV, what about
smaller scales? The maintenace issue is probably less of a factor in a
developing country than a rich country due to low labour rates.

Is just an idea,,, if someone lends me $10000 to have a go then will
try. Until then think the best thing to do is to drop it.

N. Peter Evans

peter E

2005-07-26, 12:21 am

have looked around a bit more and found these engines at 10hp, compound
engines to boot that cost $1800

http://www.tinypower.com/store.php?...ion=show_detail

unfortunately still need a generator, boiler and troughs. Plus needs
100L of water an hour, I guess you could condense most of it though.

Think this idea is well and truly dead with PV looking best way to go
for mini solar projects.

N. Peter Evans

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