DIY Solar Concentrators, Made Better.
Added 2025-07-10 16:38:00 +0000 UTCIn this video we dive into compound parabolic concentrators (CPCs) and their incredible ability to focus light from multiple input angles onto a central target at once. This allows them to provide concentrated solar heat without active solar tracking, as well as increased absorbance from indirect sources (such as scattered light in cloudy weather). The method I use in this video is called a "string construction", which uses a string to simulate the reflection of light rays and sketch out idealized reflective curves.
Comments
I found this awesome user friendly ray optics simulator: https://phydemo.app/ray-optics/simulator/ one can setup parabolic mirror, circular targets, beams... even the aperture angle of the beam can be adjusted.
Antoine
2025-07-14 17:49:29 +0000 UTCGREAT video ! i was also playing with parabolic mirror for about 1 year (mostly working on target to boil liquids and cook). if you consider a point target, your method end up drawing two parabolas on each side. in practice I imagine one could have a reflector where the angle could be adjusted with hinge to adjust for cloudy day or cloudless ones. Looking forward to prototyping !
Antoine
2025-07-13 21:15:59 +0000 UTCDo you know the formula for this shape? There are 3 distinct sections, something like a cardioid, then maybe a hyperbola, and the rest is parabolic. I printed a mock-up using splines in f360 and put aluminum tape on it. It seems to work, but I see a distinct band of light that isn't hitting the pipe from that middle curve, so I obviously got something wrong.
Peter Trench
2025-07-13 16:13:35 +0000 UTCVery cool video! The history of this CPC is fascinating. It was developed by Roland Winston 60 years ago because he needed a high-sensitivity detector in experimental particle physics. The discovery then kickstarted a whole research field known as nonimaging optics, which forms the backbone of all solar concentrator optics and important developments in illumination optics (such as those fancy reflectors used in car headlamps). Roland retired a few years ago and unfortunately passed away earlier this year, but the research field remains active. Fun fact 1: If you combine the CPC you made with a vacuum tube you can in fact get high enough temperatures to generate steam from sunlight with no moving parts. This is what Winston Cone Optics was developing recently: https://news.ucmerced.edu/news/2021/winston-cone-optics-innovative-technology-garners-state-national-attention Fun fact 2: One of the leading research groups in nonimaging optics started carrying their ideas over to completely different applications such as high-end virtual reality optics: https://virtualrealitytimes.com/2023/01/02/apple-acquires-lens-manufacturer-limbak/ I do research in this field, and help organize an annual academic conference where we bring together nonimaging optics researchers from across the world. The next one is coming up this August in San Diego, US: https://nonimaging-conference.org/ (I tried posting this comment on youtube but maybe it got blocket because I had external links. Anyway, thought you might find it interesting so I post it here intead.)
Håkon J. D. Johnsen
2025-07-12 20:05:12 +0000 UTC
