Optics Experiments on the Cheap

Introduction: Optics Experiments on the Cheap

About: I am a stone mason. My hobby is making new solar cooking and gardening stuff. I have used solar heat to cook soil for a couple of years. In mother earth news in January, i read that their compost expert does t…

This video shows a simple way to test your optics for solar reflectors before you make them. I tried (and failed) to find software to do this.
Perhaps it is a good thing that I failed!
You can find info about compound parabolics at
and at
and perhaps you could test out some of the designs they show with this simple technique!
Brian White

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    5 Discussions


    11 years ago on Introduction

    I'd imagine a better way would be to heat the 7 liters incrementally, instead of all at once, this way it should be more efficient (faster). I'd start with a fast drip/trickle feed, onto or into a preheated metal heat pipe. Aim the concentrator at the heat pipe, until it good and hot, then open a valve to slowly allow the water in. This should flash boil the water, creating steam (which could run a turbine) which can then be directed to an insulated container which is then recirculated back through the heat pipe to be further heated. This should be a lot faster to heat the water than trying to heat it all at once.


    Reply 11 years ago on Introduction

    I used a 7 liter pot because i had a 7 liter pot. And it is a a "keep it simple" solar cooking project. I wanted just to get water hot for soup or stew, etc. A turbine is not necessary.


    Reply 10 years ago on Introduction

    Sure thing, believe me, i know ALL about using what i can scrounge up or have laying around! ;-) Good on you for having the go in you to attempt this. I think it's great. Just really thinking about others who may want to generate electricity using a similar system. Another way, not using water at all, would be to focus the energy onto a small solar cell (a few inches square), this apparently can multiply the cells output by up to 1000 times! (youtube solar concentrator PV cell) Happening in Israel at the moment. A guy has a parabolic concentrator made of individual small mirror (six inch i think), and directs the beam to a small PV cell, which he says increases the rated output of the cell by upto 1000 times! Another method i was thinking of would be along the same lines of the above example, but instead of using a small PV cell, a was thinking of a bank of peltier devices with the 'cold' side in a water bath, and the concentrated light aimed on the 'hot' side...should work, unless the peltier is destroyed first with the intense heat. Nice work gaiatechnician.


    You can download an evaluation copy of Rhino3D here:


    Rhino is a cad package which, among other things, will bounce curves (as many bounces as you like) off modeled surfaces.

    It's really easy, anyone who wants me to show them how can contact me on
    sugarandfat at yahoo d0t co d0t uk


    http://www.youtube.com/watch?v=9eY0xh23Anc is the making of a dome for a 45 degree compound solar dish. This dish is undergoing testing right now.
    45 degrees acceptance angle should mean that it can cook for up to 3 hours without moving the dish.
    It is heating 7 liters of water in a pot . It has gone from 17C to 60C in 1 hr 41 minutes. (it is about 1154 am right now)