Thursday, September 21, 2006

a parabolic workshop light

I had made up a number of four foot parabolic solar reflectors for prototyping the solar heater project.

By supporting a single four foot florescent tube at the focus of one of these reflectors, I made a very effective workshop light, shown here illuminating my garage workbench.

The same ribs are used as in the longer, eight foot reflectors but with shorter side rails.

I haven't done a scientific test against a two tube fixture without a reflector, but I'm very pleased with the even and bright lighting of the bench surface and delighted to be using half of the electricity of a two tube fixture which I might have otherwise used without the reflector.

shop lighting reading list
a parabolic workshop light (this article)
led household bulbs
exploring efficient workshop lighting alternatives
work light led retrofit
testing fluorescent light fixtures - the test jig
testing fluorescent light fixtures - the test method (video)
testing fluorescent fixtures - 40 watt
efficient workshop lighting 2
updated bench lighting


David said...

What about if you rotate the fluorescent light 180 degrees so that the tube is on top and facing the reflector?

Alternatively, you could detach the arms that hold the tube ends so the light fitting is outside the reflector and the tube stays at the focus.

George Plhak said...

Hello David - thanks. Yes, the metal housing of the florescent tube does get in the way. I thought too of your second suggestion.

The next version will have a strip of LEDs along the focus, facing the reflector. There will be no large housing containing the florescent ballast. George

George Plhak said...

It occurs to me that a florescent tube needs a ground plane near it in order to light. That's the other function of the metal box. If I detached the arms as David suggested and moved the tube away from the box, the tube might not light.