Fresnel Lens Focal Length Change with Water, Concentrated Solar Power

[ringonian]

so water defeats the purpose of a solar collecting project due to changing its focal point. is it possible to keep the focal point uniform? maybe placing a straight glass pane in front of the fresnel lens similar to a dual glass window? or maybe placing another fresnel lens behind the other (short of the focal point, possibly) similar to a telescope?

[Raycheetah]

Thanks for the safety tip, Dan. Anything else we need to know about? =^[.]~=

[muddymuddymuddmann]

hEY DAN, I LOVE THE ONE I GOT FROM YOU. IT HAS ENTERTAINED ME WELL. I HAVE COOKED HOTDOGS ON IT AND MADE COFFEE AND I TRIED TO COOK SOME FISH BUT I REALLY FRIED IT .

I MADE A COVER FOR MINE AND A PRETTY GOOD STAND. ITS NOT AS PRETTY AS THE FRAME YOU MADE BUT ITS STURDY. AND ADJUSTABLE. I TRIED THE WATER THING AND GOT RESULTS OF ABOUT SEVEN FOOT. IT RUNS MY ENGINE REAL GOOD. THANKS

MUDDy

[GREENPOWERSCIENCE]

:-) Thanks MUDDy

If we every get wind here in FL I will test your turbine design. Looks really good, I just need wind.

Dan

[koenstr]

but the question is: why is the focal length increasing???

[Twistx77]

@koenstr Correct me if I'm wrong,I don't know about a Fresnel Lens but for a normal convergent lense the thicker it is the smaller the focal length is. Water works as part of the lense's thickness.

[Frosttty]

Is there any kind of laquer or some other liquid that would harden with nice optical qualities to permanently increase your focal length?

[doug2877]

nice tip

[asmundhagen]

I learned something:-)

Norway

[Shaunt1]

Amazing tool!

[madjimms]

Another great video, I love our beloved Sol......

Oh & I enjoy Dan to!

PS:where is your wife lately?

[GetMeThere1]

Very interesting! Of course, you could always have a thing plastic or glass protector to keep water off the lens--without losing TOO much light.

I suppose the water collects in the ridges, which would HUGELY change the parameters of the lens.

[CTOL1]

Cool

[TaylorHolmes]

that was your most nauseating video yet, but It still got 5 stars from me.

Dan Rojas is so tough, he eats still wool for breakfast.

[RupertsCrystals]

Wouldn't it be easier to have the groove side facing downwards? Or is the lens grooved on both sides.

Ok, I know they're not grooves, but I don't know what they're called. :-|

[Anothercoilgun]

Oooooo. Dan is smoking grass.

[marthale7]

I bet the Florida Dew might of killed some of them poor ants on the ground around you :)

[ddrusa]

awesome

[squirrelbong]

great video, is this effect caused by the water's surface or the temperature change from the water?

[globalarte]

squirrelbong :

Is caused by the refraction variation caused by the water filling the grooves

of the Fresnel surface (i think).

[pvampire]

Wow! I had no idea the focal length would change like that with water. Also, you just gave me a very good idea. I often make my own homemade charcol for black powder, filters, ect...a Fresnel would be perfect for that. Just get a quart paint can, (clean) and fill it with pine or light wood with a very small hole in the lid,....and in a small time...30 mins or less you'd have a can full of high quality charcol! Now I know I need a fresne.!!!

[pvampire]

Ususally I use a BBQ or open fire for charcol making, but I think the fresnel would be better as I'm sure the beam would be hotter than most BBQ's and definetly more effecient, plus no open flame!

[DigitalRM]

Awesome as always :)

[Ragrog105]

I didn't realize that about Fresnel lenses. Thanks for the demonstration.

[mlav85]

cool