Fresnel Lens Solar grill
by Bruce Joseph
(Tucson, AZ USA)
Bruce's Fresnel Lens Grill
I purchased a 30" x 40" linear Fresnel lens, and built a frame for it out of 2" x 2" lumber. This frame is mounted on a wooden stand which allows me to tilt the lens to align it with the sun, and raise it about 60" off of the ground.
The lens has a 42" focal length, and I'm currently cooking on a cast iron skillet placed on a modified heavy-duty camera tripod.
When I built the cooker, my goal was to boil a quart of water in less than 30 minutes. I heat water in a 2" x 22" copper pipe, and can boil over a quart in about 20 minutes.
After learning that I could boil water, I decided to try cooking food.
The Fresnel lens can get VERY hot (I would guess 700+ F) so it's very easy to burn food with it. My current technique is to place food on the cast iron skillet, then put a bacon press over that. (Similar to a panini press.) Heating the bacon press instead of directly heating the food, spreads the heat out and minimizes burning. I can cook a hamburger, a few hot dogs, a grilled cheese sandwich and other foods in about 5 minutes.
The design is a work in progress, and I'm looking to replace the lens stand with a table.
I plan to build a parabolic cooker and a box cooker later this year.
Nice to hear from you again...
And, very nice job on your write up and description of your Fresnel lens cooker.
I, and other site visitors, appreciate very much your descriptions of how you built it and especially how you have used it.
...very good submission, thank you for sharing with us.