Tuesday, November 25, 2014

Focused Sun... a low tech low concentration approach

Ugly - in a good way...

Focused Sun

They must have been in stealth mode as no pictures seem to be on the web save for the ones in the release, until Nov. 17th when they launched an Indigogo campaign. A million dollar goal and no early givers. Yikes. And the csp-world story neglected to mention the indigogo campaign.


It is much smaller than I thought based on the csp-world picture. Pretty good coverage in the video of why it is affordable.  It does not look like it is weather hard to the degree that it should be. But I like the effort to make it low tech and "makeable." I'm in the let many flowers bloom camp: but this does not seem deeply considered.

Also interesting (as a side note) that it is a collaboration between a Swede and some Americans in New Mexico. One of my favorite rivals is also designed by a Swede (the Solarus.se effort). I guess I must elevate my herring intake to stay in the game!

Take a look and let me know what you think.

Tuesday, November 11, 2014

PowerPanel guys are still plugging away. I love the tank design. ALOT.

Check out the video at the bottom of their home page: hot water storage could not be easier I think. Up to 200 F and it can be walked through any doorway and fits 350 gallons. (that's 93 C and 1325 l)

It looks like there are really only two foam parts (wall and half top/bottom) and a liner and an external girdle. Just all kinds of clever. Wish they'd show a price for it.


My design does not require storage. I just love smart. And this is smart stuff.

Irradiation evenness... getting better by a bunch

Thought I'd tease a bit of the recent findings from the optics team:

Earliest proof of concept:

takeaway... not good but the photons do get there... and I learned a lot.

Knowing where the trouble comes from (and rethinking many other tangentially important elements) gets us this:

these are not the same scale (btw) what we care about is the evenness of the light and of the image. The low value (or more precisely intensity) yellow smear is easily corrected (nearly a column above.) The cell size can now drop to about 1/5 the original intended size. I've not tiled it as a hexagon (an even better fit if you hope to grab circular images with fewer wasted margins. ) Hexagons should fit even better on parent wafers... quick estimate 500 per 156mm pseudo square... that is a tiny bit of Silicon serving a very large aperture.

I am trying to characterize the packing factor (how much margin is lost by the space between cells). Or in my case the space between individual mirror "wells." It is better for the heat (.95 or so) than for the PV but if those smears above get into the center they might scavenge  us up to 92 or so. Which would add aperture-efficiency to our list of accomplishments.

Stay tuned!

Study from the Thermal side of the house...

Thermal Plant .(com) is my new internet crush!

Here are some compelling figures on hybrid PVT systems from a thermal perspective. Optimization of the thermal fraction is their agenda and they pound TRNSYS to get some insight. Cool.

here is some of it:

The performance of the PVT system consists in the renewable energy production, net of auxiliary devices’ consumption. Expressed in terms of primary energy, this balance is in general considered an energy saving for the users. Obtained results are shown in the following figures.

Fig. 7. Total energy saving in case of electric heater and natural gas heater
Fig. 7. Total energy saving in case of electric heater and natural gas heater Fig. 7. Total energy saving in case of electric heater and natural gas heater

 By observing the graphs, it can be seen that primary energy savings are much more consistent in case of electric heater in comparison with natural gas one. Anyway, in both cases, by increasing the PVT collector surface the total energy saving is not increasing linearly, which leads to conclude that global system efficiency is slightly decreasing by increasing PVT area.
This  happens  because  the  largest  number  of  collectors  increases  the  heat  transfer  fluid  mean temperature in each loop, while progressively reducing both the PV and thermal efficiency.
However, to perform a complete assessment of the PVT energy performance, global system costs and
savings potentials must be taken in consideration, as reported hereafter.