receiver for parabolic dish solar concentrator

[nic]

If there are any survivors please tell us all about the experiment.

Now is the time when the survivors report about the experiment! Both our school projects have ended
with some interesting results, but the concentrators are not fully complete. There are still some things
I'll have to improve and finish, but let's say a good prototype (for both projects) was built.

You can read both reports my students wrote on my webpage:

http://www.nicolascretton.ch/index_LM.html

under the section "Diploma done during 2012". Since we live in the
Italian speaking part of Switzerland, the reports are in Italian, but
one can look at the pics and graphics...

In particular,

parabolic trough concentrator:

http://www.nicolascretton.ch/LM/LAM_Grueninger_Kunnakatt_Marcotullio.pdf

parabolic dish concentrato:

http://www.nicolascretton.ch/LM/LAM_Knecht_Kick_Cassis_Nicoli.pdf

videos:

http://www.nicolascretton.ch/video_dish.mp4

http://www.nicolascretton.ch/video_test_with_water.mov

As I said, I will go one working on both projects, maybe with other
students and I will report on this forum.

[russ]

Georges did two different versions of his parabolic trough concentrator: the old one (about 2 years ago) with a simple non insulated tube, and more recently, I believe last summer, he did one with a vacuum tube. (see the links in my previous message).

Ok - I will look at that - hadn't seen it!

[nic]

Some commercial parabolic concentrators do use a vacuum tube rather than like George's - a different thing altogether.

Georges did two different versions of his parabolic trough concentrator: the old one (about 2 years ago) with a simple non insulated tube, and more recently, I believe last summer, he did one with a vacuum tube. (see the links in my previous message).

[russ]

Some commercial parabolic concentrators do use a vacuum tube rather than like George's - a different thing altogether.

[nic]

In some of the commercial designs they do and people fail to see all the differences - it is expensive and not simple or easy.

the difference with respect to non-vacuum-insulated tubes, like flat classical panels?
hard to believe there is no difference in the winter, since vacuum tubes really reduce the heat losses (especially critical in the winter).

Now, maybe you mean the difference between fixed flat panels (with vacuum tubes) vs tracking concentrating troughs (with vacuum tubes) ?

Georges has done interesting tests (concentrator vs flat panels), although both with vacuum tubes and with tracking, so it might not
be relevant to what you had in mind.

http://georgesworkshop.blogspot.ca/2011/10/index-comparing-concentrator-to-flat.html

http://georgesworkshop.blogspot.ca/2011/12/conclusions.html

[nic]

Are you saying you plan to use a vacuum tube in a concentrator?

for our trough project, yes. It is very similar to http://georgesworkshop.blogspot.ca/2...-20-intro.html

[russ]

Are you saying you plan to use a vacuum tube in a concentrator?

In some of the commercial designs they do and people fail to see all the differences - it is expensive and not simple or easy.

[Naptown]

The working fluid we plan to use is Tyfocor LS. It's an antifreeze fluid, the same fluid than the one used in "classical" solar panels with vacuum tubes. It has nice properties (anti-corosion, resistance to heat).

As for the manifold, we'll have to build one made-to-measure, because of the large distance between tubes (around 60 cm). The manifold for solar panels with vacuum tubes have a much shorter distance between the tubes (in the picture attached, the manifold is shown as the bottom figure). As you can see, the copper header will be insulated to reduce heat losses in the manifold.

[ATTACH=CONFIG]2624[/ATTACH]

Are you saying you plan to use a vacuum tube in a concentrator?

[nic]

What is your working fluid ?

An aluminum block, 24" square, with a grid network of holes and manifolds drilled through it, and the blank ends "plugged" with threaded plugs, will collect and transfer a lot of heat for you. After it's machined, the outer surface is anodized black, to absorb energy better. As long as you keep pumping fluid through it, it's pretty safe, but if you overheat it, you will destroy it.

The working fluid we plan to use is Tyfocor LS. It's an antifreeze fluid, the same fluid than the one used in "classical" solar panels with vacuum tubes. It has nice properties (anti-corosion, resistance to heat).

As for the manifold, we'll have to build one made-to-measure, because of the large distance between tubes (around 60 cm). The manifold for solar panels with vacuum tubes have a much shorter distance between the tubes (in the picture attached, the manifold is shown as the bottom figure). As you can see, the copper header will be insulated to reduce heat losses in the manifold.

figure_manifold.jpg

[russ]

A parabolic trough concentrator is far safer as regards temperatures.

[Mike90250]

What is your working fluid ?

An aluminum block, 24" square, with a grid network of holes and manifolds drilled through it, and the blank ends "plugged" with threaded plugs, will collect and transfer a lot of heat for you. After it's machined, the outer surface is anodized black, to absorb energy better. As long as you keep pumping fluid through it, it's pretty safe, but if you overheat it, you will destroy it.

[Logan5]

I am new here and want to see these pic's. name is Logan

Hello,

with my students, we are building a solar tracker using a 180cm parabolic dish
(pretty much like this one: http://www.heliotrack.com/Dish180.html ).

We have the tracking almost under control but my question here is about the
receiver which should be placed at the focus of the parabola. The heat fluid should
go through "spiraling" pipes in the receiver, get heated and then go back to the water
tank in the house.

Does anyone know where to buy such a receiver (even second hand)? if not, can anyone
help us on how to build it (material, dimension, etc).

thanks,
Nic

I have a 1 meter dish. also considering converting it to concentrated solar water heating.

[russ]

Yes - a Redrock kit as I remember

[ReggieThe Dog]

Comments within the text

Nicely put Russ... I'll invest in one of those upmarket things if ever I become a millionaire. Until then I'll settle with our reservoir, despite having to share it with the ducks... hee hee
I have looked at Georges stuff before and to be fair about thirty other websites. George, as you say lays things out quite nicely and his set up is nicely arranged Though for tracking I believe he's using a redRok kit if my eyes don't deceive me.

[nic]

Nic - I thought George had really laid things out nicely for the average person with shop skills to follow.

Looking forward to seeing more of your work.

yes, true. George's model was immensely useful for us and I would recommend his brochure to everybody. I bought his brochure, but we had to make a few modifications, since his intent was for the summer (for the swimming pool). We wanted to use the troughs in the winter for house heating purposes, so we chose vacuum glass tubes, much more fragile than Georges original design (about 1.5 years ago). Hence all the "trouble" with the bearings and weight support.

On our side, I will post our final document on my webpage. Unfortunately, since we are in an Italian-speaking region, the diploma of my students will be written in Italian, as required by the high school regulation. More later.