solar thermal

show all solar thermal new to old

pool heater time lapse one day
Time lapse movie. Viewed from west end. A mostly clear day. Shows the movement of the solar array as the sun passes overhead. One pic every 60 seconds.
My most popular YouTube video.
how to make solar superheated steam

For some time I have been working with DIY parabolic solar collectors. Often I am asked if I can make steam? Yes, I can. This report is about my steam test.

Summary/Conclusion - DIY Flat Plate vs. Concentrator Performance

The parabolic trough concentrator (example mounted on the right side of the solar test jig in the picture), is used in large thermal plants in the desert but is not often home built like the "flat plate" type collector (example at the left. Both make great Do It Yourself (DIY) projects that can be adapted to local needs. Both work well. How does their performance compare? I decided to find out. I was surprised that my two fairly carefully researched and constructed models were fairly close in performance. But there were some big differences.

diy solar parabolic trough gen2 intro

I have been working on an update of my book based on some work I did which I am calling gen2. This item details some thoughts and goals.

More about evacuated tubes for parabolic troughs

I use common glass evacuated tubes as an insulated collector for a DIY parabolic trough concentrating collector. With the addition of a rotatable tracking parabolic trough behind a single evacuated tube, it is possible to increase the heat capture significantly, up to 8-15x safely. In this manner, it would be possible to do things that are not possible with a flat plate or an evacuated tube system - making steam for example. In a recent demonstration I showed that temperatures of over 630°F are possible on an experimental DIY basis.

solar pool heating with a parabolic trough

Links to some work I have done on solar pool heating.

solar tracking motor drive explained

I created this short amateur video to help explain some aspects about the motor drive that I am using for the diy gen2 solar parabolic trough heater. The actual motor drive in this video has been in service for five years in a Canadian climate running a tracking heater for a swimming pool.

The story video - done by a friend - on Youtube
cleaning parabolas easily

You've got parabolas to clean? My friend Richard shows how in a video at the end

solar bbq

This home built solar cooker is a parabolic solar reflector with a spit rod at the focus. A simple aligner post at the bottom front shows clearly when it is perfectly aimed at the sun. Aiming seems not that critical and the post makes it easy. We checked and moved very slightly only once during 1/2 hour of cooking.


Jon C. Fox said...

Wouldn't a non-imaging tracking solar concentrator be better - no motor or electronics needed, no moving parts? Roland Winston described these in his layperson-oriented article in a 1991 Scientific American:

but he and several others worked on this even earlier. A decent ray-tracing diagram is here:

I've also heard this described as a 'crab-eye' reflector, since apparently crabs owe their excellent peripheral vision to having compound parabolic eyes.

Since most optics are imaging, non-imaging optics is not as widely known, but for solar applications, especially thermal, these look great. However, I've not come across any DIY 'Winston' collectors. The basic construction techniques you use for your tracking parabolic concentrators might be applicable, but the underlying shape is different.

Have you already looked into 'Winston' collectors?

George Plhak said...

Yes. I know them as Compound Parabolic Collector (CPC). Whether CPC (or Winston) are "better" might depend upon the site location and the objectives of the installation.

I did not experiment with CPC, but there are many references on the interweb.

Thanks Jon!