parabolic solar trough

[joji]

Howdy. I built the solar trough collector as described in www.solarflower.org and I am quite happy with it. It boils water in about two minutes. Now I am working on version 2.0 from metal instead of wood. I am going to use Arduino solar tracker that will be driving small servo for one axis tracking.
https://www.youtube.com/watch?featur...&v=3ci4T3GU7oU
https://www.youtube.com/watch?featur...&v=W1r4ImkoO_o
This is the guide I followed for the tracker http://mad-science.wonderhowto.com/h...acker-0137747/.
Also for the collector 2.0 itself I made sketchup drawings. https://drive.google.com/open?id=0B6...EVsaTlEeFBDNHM I was wondering if anyone could comment on this project and provide suggestions/constructive criticism. The goal is to heat water for the beginning. If all goes well I would like to produce electricity.
Peace

[Guest]

Can you take a screenshot of your design instead. I dont want to find and download program to open your specific file my friend
I do like Parabolics and think it would be great.

What do you mean by "I would like to produce electricity.
Im interested to know your idea..

[joji]

There you have it updated. Well for starter I will just heat water. But later after I improve it I want to hook it up to some sort of turbine. I am building now small tesla turbine as a proof of concept. Will see how that goes. Perhaps I will post about that later. If tesla turbine won't be any good I am considering to buy steam engine and hook it up with generator. Preferably in a closed loop.

[Guest]

What sort of materials will you use. What kinda of mirror reflection will you use for the parabolic. Finding that kinda of material probably expensive. What do you think
Thanks for updating with pics!

[joji]

The first version that I built has wooden frame. It's not sturdy enough. I might just use more wood but I don't like it because it's too flexible. It's twisting a bit. Plan is to use metal frame for the new version. Mirror is from polished aluminium plate. It's not expensive. One plate that is roughly 1M x 1.2M size cost me some 6 euro.

[Guest]

Interesting man. Very interesting I didnt know they had polished aluminum plate which is Great!. Im sure when the Sun hits the plate it will infact heat the polished aluminum causing less focal heat to a given area. As im sure when the sun hits the plate the aluminum will have thermal properties which heats the aluminum so you should expect less heat transmission to where you are directing the sun-rays.
What is your opinion.

[joji]

Reflectivity of polished aluminium is something about 90% which is good enough for me. I am going the cheap way. Make it cheap, yet efficient and simple. That is my mantra.

[Guest]

True.. but I wasnt refering to reflectivity. I was just speaking about the thermal principle of aluminum since it tends to heat very quickly. which will transmit less heat to your focal area you are trying to boil.

[jflorey2]

There you have it updated. Well for starter I will just heat water. But later after I improve it I want to hook it up to some sort of turbine. I am building now small tesla turbine as a proof of concept. Will see how that goes. Perhaps I will post about that later. If tesla turbine won't be any good I am considering to buy steam engine and hook it up with generator. Preferably in a closed loop.

Just to save you from disappointment, small steam engines/small turbines are some of the most inefficient devices out there. If you are doing it for a demo, then great; you can definitely get something that will light LED's or something using off the shelf components. But if your goal is actual power you'd be much better off with concentrating PV.

[joji]

True.. but I wasnt refering to reflectivity. I was just speaking about the thermal principle of aluminum since it tends to heat very quickly. which will transmit less heat to your focal area you are trying to boil.

different wavelength have different reflectivity on aluminium. https://laserbeamproducts.wordpress....-and-infrared/
But why bother? The first ****ty version of collector I built can boil water in 2 minutes. But I am open for suggestions. That is the reason I posted here after all. Can you suggest better material that is not supper expensive? I would be glad

[Guest]

Glad you asked my friend. This is all about conversation and exploring possibilities openly with one another.
And as far As I can think I believe this mirror sheets would and could work better. I believe it has similar reflectiveness.
And more than likely it will not heat itself as bad as aluminum, but I could be wrong but I doubt it.
Ive bought this product recently and the mirror reflective is outstanding. No complaints. It is 80-90percent reflective I believe. Pretty clear for such a material.

Perhaps sticking this on a material that has very Low thermal conductivity would be best. Being that this is very thin material it can bounce heat very quickly if the underlay is low thermal conductive
http://www.ebay.com/itm/Wall-Foil-Mi...16.m2518.l4276

[joji]

Just to save you from disappointment, small steam engines/small turbines are some of the most inefficient devices out there. If you are doing it for a demo, then great; you can definitely get something that will light LED's or something using off the shelf components. But if your goal is actual power you'd be much better off with concentrating PV.

These guys are selling 10KW steam engine

http://www.steamengineworks.com/tech-specs/

I know that efficiency will be low but considering sun is shining for free, I am ok with it. Definitely planning to use PV as well. If this parabolic concentrator proves to be any good for power generation I will just multiply the quantity. Perhaps increase the efficiency by improvements. Worst case I will use it just to warm up water.

[jflorey2]

Definitely planning to use PV as well.

OK. From the numbers on that page, the efficiency of that steam engine is about 6%. If your collector efficiency is 50%, then your overall efficiency is 3%. Compare to solar-PV which is around 15%.

[joji]

OK. From the numbers on that page, the efficiency of that steam engine is about 6%. If your collector efficiency is 50%, then your overall efficiency is 3%. Compare to solar-PV which is around 15%.

I did say that I am planning to use PV as well you know? But this is something you can make on your backyard from scrap material. Try to do that with PV.

[jflorey2]

I did say that I am planning to use PV as well you know? But this is something you can make on your backyard from scrap material. Try to do that with PV.

I suspect you would have better luck making PV from scrap material than making a steam engine/generator from scrap material. Here's one way to do it:

http://www.instructables.com/id/DIY-solar-cell-from-scratch/

But like I said, if you are going to do it just for fun, go for it. There are worse hobbies.