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Solar chimney

Posted: Fri May 05, 2023 7:06 am
by Joeboy

Re: Solar chimney

Posted: Fri May 05, 2023 8:22 am
by Moxi
Am I missing something here or have they just invented a wind turbine that only works in sunny conditions and appears to take up a massive amount of space horizontally and vertically when compared with a conventional turbine ? It would be interesting to know what the area covered was so that you could run a comparison with the same space covered in just solar panels.

I expect the next great idea to improve the induced draft turbine would be to spray cold water just after the turbine position to create a pressure drop and increase the updraft velocity as they do in conventional thermal power stations at the condenser unit.

Moxi

Re: Solar chimney

Posted: Fri May 05, 2023 9:13 am
by Joeboy
I would suspect a desert location? 🏜 It looks like a low tech, materials cheap way to turn a turbine.

Re: Solar chimney

Posted: Fri May 05, 2023 9:16 am
by AE-NMidlands
I would guess it might be aimed at places where it is often very hot and the air is still. I'm surprised that the wind doesn't affect it though, surely chimneys draw better with a wind across the top?
How about using pv panels for the greenhouse glass around the E, S and W to get a different additional output?
I also wonder whether its output - if it works at all - would continue on into the evening as the ambient air temp drops (apparently it's often freezing overnight in really hot deserts.) There will be quite a thermal mass under the collector area, or could be if you wanted it and it didn't handicap the air heater too much.
Image
seems to show asphalt over sand and gravel layers with insulation under that. I would expect the asphalt volatiles to evaporate off and coat the underside of the absorber pretty quickly, but if it's IR coming through that might not bee too much of a problem.

Re: Solar chimney

Posted: Fri May 05, 2023 9:24 am
by Bugtownboy
One of the papers proposed water filled heat tubes under the collector rather than relying on underlying sand & gravel.

Spanish prototype generated electricity for 7 years at low cost.

Interesting concept for certain locations.

Re: Solar chimney

Posted: Fri May 05, 2023 9:30 am
by marshman
Its an "old" idea. Some of the references date back to 2010 and earlier. I recall this was "debated" in the old forum.II.F Advantages


Extract from the Encyclopedia of Physical Science and Technology 2003

Solar chimneys operate simply and have a number of other advantages:

1. The collector can use all solar radiation, both direct and diffused. This is crucial for tropical countries, where the sky is frequently overcast.

2. Due to the heat storage system the solar chimney will operate 24 hr on pure solar energy. The water tubes under the glass roof absorb part of the radiated energy during the day and release it into the collector at night. Thus solar chimneys produce electricity at night as well.

3. Solar chimneys are particularly reliable and not liable to break down, in comparison with other solar generating plants.



It's "advantage" is that it is effectively a "solar generator" where a proportion of the energy (heat) is stored at the base of the chimney and then released at night when the sun goes down. The idea is that you then get continuous generation. I suspect that PV with battery storage would now be more efficient and reliable - tech has moved on a lot in the intervening years.