"Compound" parabolic solar cooker, make a template with technical drawing

Step 7 Other people's work

Other people have traveled the compound parabolic road.
Anyone who designs a flashlight reflector or lampshade reflector to spread out the light from the bulb is doing something similar, just doing it in reverse!
A guy called Roland Winston had patents for compound parabolic troughs. The patents have now expired and are online. He is a well respected scientist. He did things probably the perfectly mathematically correct way so I will put one of his patent drawings here. I found it online on about the 14th of January 2009. (Pity I did not see it earlier)
Here is a picture of one of them from the patent application itself! As you can see, he has a bump or dimple under the receiver. Once again, I do not know how this will work when we make a dish.
He seems to use 2 parabolas without a combined focus. Please take a look.
I do not know if I am allowed to show the entire patent (I have it in pdf format on my computer) it is easy to search for it, if you just put in the patent number and winston in your search.
As you can see, it is fairly similar to what I came up with but it is a trough not a dish.
Brian

Comments

[mscir]

Great article, thanks!
Please post the patent number for the work you mention by Roland Winston, I'd like to see what he did.
I wrote a freeware program that calculates parabolas of any depth and diameter, you can see or download it here . I'm thinking of writing a calculator to help people make compound parabolic collectors as you've described in this article, they are extremely useful because they don't have to be aimed as parabolic reflectors do, looking at his patent might help me get a few ideas about how to approach it.
Thanks, Mike

[gaiatechnician]

Hi, Mike, glad to hear from you. I gave a talk in February and in the research for it I found a very good pdf about Winston and other curves. (All seem to be for troughs). Anyway, several might be good, winstons with a 47 degree acceptance angle, (horizontal and aimed at the equinox sun would work), and there are 2 "seashell" troughs, and the trombe minell cusp. I don't remember the patent no. but if you send me your email address, I can send you the "interesting curves" PDF, etc.
It contains some of the math that you need.
Anyway, the seashell troughs are completely new to me but they help show that I was on the right track with my "clam shaped" solar cookers. (Even if I only ever made one).
Have you seen the solar design T-square? Thats what I used to make the clam shaped design. Maybe you could do a better design and more repeatable design with your grasp of mathematics? Brian

[User113]

Patents themselves are public domain, you can always copy and publish them (the documents themselves), even if they have not expired. The idea behind patents is that by telling others how to make and use the invention, they (the others) will be able to use that knowledge to improve other things. There is an incredible amount of information residing in the U.S. patent database, just waiting to be rediscovered and/or reapplied.

However, if the patents have not expired, you just have to be careful about making, using, offering to sell, selling or importing anything that is covered by the patent's claims. All modern U.S. patents have claims. See 35 U.S.C. 271.

[Kwena Moxadi]

Hello, I'm a first year student for engineering and we've been given a project to design and construct a solar cooker. I'm finding it hard to follow these steps because I'm not familiar with all the technical steps. please summarise these steps in simpler language for me to follow, starting even with potential material to be used. I'd appreciate it so much if you do. pictures not necessary.