entasis79-

its cool that you stumbled onto those writings...
i was actually really interested in this stuff a few years back and spent the better part of the semester thinking about, sketching, and reading about possible solar engines.

as metamechanic refered to, schlaich is doing a solar chimney in [http://www.enviromission.com.au/]Australia[/url]

it will produce a significant amount of energy and has tremendous potential where the space and solar energy is available. Its very low maintenance, zero pollution and really only requires the initial capital investment and little more.

there was a 50kwh prototype built in spain in the 80's which you can find information on all over the place.

The idea that one could generate any significant amount of power on the scale of a single building with this type of technology was roundly shot down by all my profs as well as the MP who wrote those articles you reference, but the secondary idea i also pursued for a bit was to have such a system basically roofing a large complex...

i messed up the link above... sorry

Australia

ha...i was just about to post about your mini-obsession with integrating those solar engines, lletdownl...

the solar flue does work as a great passive ventilation tool...

for power generation, we were thinking more along the lines of a campus wide or high-rise tower wide power generation tool... something that would actually create a differential pressure great enough to turn a turbine...

sadly, i think the investment needed would far outweigh any kind of integrated power generation tool that is building scale... only those massive towers with that crazy height can become (sorta) feasible...

i wanted so badly to use all the heat thrown off by our computers to generate meaningful energy, that "idea" died long ago...but passively relieving that heat from the space is big $$ and bigger eco-friendliness

I worked on a house in Tucson years ago where we did a number of these ventilation shafts. I never did hear if they worked. However, Line and Space did a project based upon the same principles. There was something similar used in Phoenix years ago to cool a large civic plaza. The architect was Carl Rahl, I believe. It wasn't for generating
electricity, but was for introducing a mist of water into the ventilation shafts. Actually Liberty might have been around when this work was going on. The house I worked on was for the Librarian for the University of Arizona Librarian and her husband. It was the design of William Cook. Carl was at the Univeristy of Arizona, experimental station, where they were doing all sorts of interesting projects from raising shrimp, making salt, and playing with plant types in the desert along with Architectural designs for desert regions.

The proposed tower in Austrailia looks amazing. This video gives a great idea of what it would look like.

Can you imagine seeing this beautiful 1000 meter tall tower off in the distance?!? Or the view from the top? Amazing.

The initial costs on building something like that must be astronomical, I would imagine.

Did you guys ever come up with a proposal for your complex roof top tower that you thought would be viable? It seems like a great idea.

Snooker, in your Tucson house, how did the cool air enter the space? I have seen images where there is some type of pipe that brings in cooled air from the ground beneath the house, is this common?

we never were able to spend enough time on it to get a viable option... and its really a stretch to say that there is a viable option. The volume of air that must be moved in order to create quality wind for the turbines requires a massive coverage area, and in order to provide a significant enough pressure differential the tower must reach to much cooler air (hence a 1000m tower). Obviously integrating both of those requirements into a complex where people will be is difficult not only due to cost but comfort as well... who would want to spend their days in the beating sun under a massive glass canopy?

there might be ways to lower the height of the tower, such as introducing mist or some other coolant to create the pressure differential between base and top artificially... Williams idea about a heat exchanger could possibly allow the height of the tower to come down if it would work, but only because in theory, it would allow for more of the heat energy to be transfered into the incoming air.

i think if this topic is something you are interested in, you should read up on solar engines as well as these passive systems as i personally think there is a lot of potential in existing technologies reinterpreted by modern and future technologies... we are already seeing it with the effect nano-technology is having on PV technology. I have always been fascinated in particular by the Stirling engine... i did another side project theorizing ways series of solar powered stirling engines could be used.

not electricity generating, but the cooling towers at the Zion National Park Visitor Center in Utah are said to work very well.






I'm hoping to make it over there this summer, I'll let you know firsthand

Here is a picture of the Line and Space Project:

FRO, thanks for the images! Definitely let us know about it when you go.

lletdownl,
The Stirling engine is something that I feel like I could easily become obsessed with now, thanks!

I would love to hear more about the solar powered stirling engine! That sounds very interesting.

The cool tower at Zions works well from my experience. But it cools by the cooler air dropping, after having taken on moisture from the wet mats covering the openings; the inverse of the solar flue idea (hot air out the top. When you sit by the openings you can actually feel a cool breeze, definitely worth a visit.
j

anyone know of any firms anywhere in the US that are pushing/investigating this type of technology for buildable projects?

toroid, are you speaking of passive design in general? or cooling towers? or solar flues?

passive design elements are very regional and climate specific, so as far as a firm pushing one specific element, i don't think that's too common. any good environmental engineering firm and green thinking architect will more than likely explore the possibilities of passive design in a project. (at least that's how it ought to be)

there was a decent article in archrecord this month..."getting aggressive about passive design" and highlights some of the trends...but the firms and projects it highlights (SCB, NBBJ) are by no means all-stars of the industry.

hope that's a decent enough start for you...

entasis79
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it wasnt a terribly complicated concept but is difficult to describe without visuals... but the gist of it was that a series of individual solar engines would be set in series, each engine contributing its small amount of work to the bigger system, each module would be as small and light weight as possible. the side facing direct solar radiation would be an air tight, fixed volume, glass enclosed, heavily insulated space. it would be seperated from the back of the system by a piston like mechanism.
in a set, closed volume, as temperature increases, as does pressure. the air heating up pressures the piston backwards driving a weighted wheel up like a gear as well as revealing a pressure release valve. the heated air in the closed volume is released at the top, and cooler air (possibly through ground source pumps or otherwise) would be sucked in at the bottom by the vacuume created. the cooler air being more dense would be easier for the returning piston to compress as it moves back forward, and the cycle would begin again.

this wasnt a typical sterling system, however, as i proposed an open system instead of closed... meaning there would be an exchange of air at the end of every cycle rather than cooling then heating the same air. again, this wouldnt be an efficient system at all, and might generate next to no power, but if the modules could be miniturized and then set in arrays of thousands, its possible they could have higher efficiencies than pv, as stirling engines are theoretically much much much more efficient than any other kind of engines we have made

i did a project on it in undergrad with drawings... if your further interested, perhaps i could show you some diagrams

lletdownl,
It sounds like a very interesting idea (an open Stirling).
It seems like the idea of a solar powered stirling engine (or a series of them) has such incredible potential. This is why my obsession is starting to take hold.
If you would be willing to share a PDF or something, that would be great!

Postal, thanks for the Archrecord article! I can't wait to read that.

I have a rather dumb question about passive design...

How would you define it?

I see that term used quite a bit and it has become somewhat of a blanket word for many sustainable designs and ideas. Can someone help me out?

the easiest way i think to define it:
a design strategy that uses zero energy beyond the initial capital investment...no moving parts etc....

i can definately see how this term gets jumbled up, because a building can rarely be entirely passive... so a portion of the performance of a passive concept may be enhanced by an "active" mechanism (fan)...(swamp cooling, earth tubes/labyrinths, etc) see what I'm getting at?

so, in most cases passive design will only get you so far towards creating a year round comfortable environment... it includes solar orientation, thermal mass, earth tubes, solar flues, cooling towers, etc...

the next step is to integrate every possible known strategy to use as little energy as possible to heat or cool, humidify or dehumidify the air as needed... then on top of that see if you can implent some kind of local power generation to supplement the power needed for the active systems... then think about water conservation, gray water re-use, rain collecting etc.., then think about the recycling of building materials, embodied energy, etc... then thin... honestly the list goes on and on, and there's no one single optimal combination... but it's always important to be very site specific... i recommend reading anything by ken yeang. there are better books on passive design, but yeang doesn't get caught up in one aspect of design (power generation, passive design, etc.) but rather tries to add everything up...it's quite remarkable, that one would even try to collect and analyze all this information on a building by building basis, but i'm happy to say that people are trying to do it to the best of their abilities...

but, if you're interested, you should see if your school has a class about these issues, for us it was integrated into our mech/elec courses...the issue is huge, and i'm fairly certain my undestanding of these concepts are not what they should be...

we trying to use solar chimneys to cool down our warehouse.
ive been doing some research over the past few months, and
we are going to start building them in july or august.

is the great article Postal talked about in Arch Record.

It is a great read if you are interested in some of the current "passive" projects.
Thanks Postal.

Also, thanks for the explanation as to what constitutes "passive". Your right, it does seem to get jumbled up.
I will absolutely look into a class about this at school.

Lego, how large of an area is your warehouse?

How many chimneys do you need to cool that area?

I am excited that a passive system like this could be viable for what I would imagine is a large volume.