What's this

[Jayson Woodruff]

Wanted to see if anyone knows what this is. Interesting.



Jay W

[Eric Clements]

Solar collector.

[Jeff Shyu]

yeah, i was thinking PV panel too. looks fragile.

[Jayson Woodruff]

Well that was fast. But its special for many reasons. Here's a few: 3kW from 9am to 7pm (as oppose to the bad bell curve that is typical), in production would be <$3K (but you need to buy in 'bulk') and is already outdated on paper by a cheaper, more efficient version.

Practical solar power is coming fast.

Jay W

[Jeff Shyu]

yeah, walmart's been eye'ing how cost efficient it would be to put PV up on their roof (150~200k SF).

the problem is, WM is already so energy efficient, the meter would just be rolling back the entire day, and most cities don't want to pay WM back for the energy.

[Mako Koiwai]

Walmart Green Store:

http://www.networkworld.com/community/node/26110

I thought they also had a cold climate store that had a lot of tricks, including underground storage of heat, etc.

[Jeff Shyu]

all the stores we build for them in CA are coming up to speed on their new HE5 specs.

WM is really ahead of the curve on the whole "green building" thing, which has been a problem for us when we go to a city that requires LEED certification. the design already exceeds LEED requirements, but we end up having to pay to get it certified, to show that it's already performing above spec.

[David Avard]

How big/heavy is that thing? Looks about 8' x 20', which would put it at 15' tall. Too big/heavy for rooftops (of homes).

[Tom Tanquary]

Is this something you're working on? Is it built locally? Is there any press o this yet?

[George Schilling]

yeah, walmart's been eye'ing how cost efficient it would be to put PV up on their roof (150~200k SF).

the problem is, WM is already so energy efficient, the meter would just be rolling back the entire day, and most cities don't want to pay WM back for the energy.

Those b*st*rds. He's another reason for Wal Mart haters to hate Wall Mart...........taking money from public utilities through efficiency and innovation. What will they do next?

[Jeff Shyu]

little known Walmart fact:

Walmart invited Target design directors (among a ton of other design people) to a visit of the Walmart building to show off the technology.

they didn't take WM up on it.

anyways, back on PV panels. I've been hearing a lot about new/better/more efficient products that are "due to be released SOON", but haven't really seen anything with solid performance numbers / prices to back em up. I'd really like to see this go somewhere positive.

[Jayson Woodruff]

How big/heavy is that thing? Looks about 8' x 20', which would put it at 15' tall. Too big/heavy for rooftops (of homes).

That's about right, but it's really not that heavy, mostly made from plastic with fairly thin gauge alumnimum structure. Wind loading is where you get the forces.

It's inteded to be foundation mounted, but could go on specially constructed roof tops. It's a high concentrator PV*, so needs to be on a sun tracker device. This is why you get the full flat power rather than the bell curve. The target is for this to be in a large field for utility tie in (10+MegaW). I think if this concept makes it to full production, why wouldn't there be a market for it for commercial or event residential use. These 3 to 5kW panels wouldn't take up but half an urban back yard. Put it up a little bit higher than shown and you can still use that land space.

*High concentrator PV is where the sun collects into a magnifying reflector and is reflected onto a much smaller piece of solar cell. This keeps the amount of solar cell material lower while still catching all that sun. Solar cells are also found to be MORE efficient with concentrated sun light as well, which was not intuitive to me. Trade offs are need for the tracker and need to dump heat. The one shown in the picture is a 800x concentrator. Next rev is a 900x and doesn't have the heatsinks shown sticking straight out of the modules (they're tucked behind in the shade).

It's something I used to work on. This is an operating 'proof of design' (which means it works as specified, just doesn't yet meet cost/production targets) at Seal Beach.

Jay W

[Larry Andrews]

Jay - how do the dark cylinders work? Where's the reflectors? It's sorta hard to tell from the image.

Very, very cool stuffs though. I'm genuinely impressed. -la

[Jeff Shyu]

my guess is that the black prongs are what your typical PV cells are, but laid out in a cylindrical form. the reflectors are the silver parts around each of those black prongs.

edit: like a miniature version of this:


they had that in the 007 movie, casino royale

[Jayson Woodruff]

The solar cell is only about 1 sq cm per module (each 20-25W) and is mounted at the bottom of the black things facing 'down'. The sun is being refected out of the bowls to the cells. The black things are just big heat sinks (800-900suns need cooling). They're pointing up that way to minimize shadowing, but all that geometry is changing as mentioned earlier.

edit: like a miniature version of this:

I think you have a power tower there. While not photovoltaic, it's still 'solar power'. The reflectors point and concentrate light on a heat engine of some sort (steam a lot of times) and that engine pumps and creates power. Simple, and cheap, but has really 'topped out' in technology, so it's not going to get any better. Wind has similar 'issues'.

[Will Kalman]

I think you have a power tower there. While not photovoltaic, it's still 'solar power'. The reflectors point and concentrate light on a heat engine of some sort (steam a lot of times) and that engine pumps and creates power. Simple, and cheap, but has really 'topped out' in technology, so it's not going to get any better. Wind has similar 'issues'.

Actually,what he's got there is a solar updraft tower as all the bottom section panels are all parallel to the ground and there doesn't seem to be a collector at the top.

The solar energy heats up air in the flat part which then rises up past a turbine or turbines in the base of the "chimney".

http://en.wikipedia.org/wiki/Solar_updraft_tower" onclick="window.open(this.href);return false;

Yep, here's a video of the installation pictured...

http://video.google.com/videoplay?docid ... 7410595527" onclick="window.open(this.href);return false;

[Jeff Shyu]

damn you people with your eyes..

i was looking for the picture of the solar collector from the Casino Royale movie, and that was the closest i could find.