I spend a lot of time looking at appropriate technologies coming from missionaries and other groups that work in third world countries.
I figure – if it works in areas lacking infrastructure then it will work if we ever lose our infrastructure.
This idea came from a couple of YouTube videos I saw of people making water bottle skylights out of 20oz soda bottles.
This is also called a solar bottle bulb. Either way, the concept is pretty simple I have used this in domes and animal houses several times.
Most specifically I got it from the video at the bottom of this page.
I modified it slightly and was quite pleased that two of them gave enough light in my cement dome that I can see what I am doing.
Actually, if I am in the general area of one of the lights I can actually read by the light.
- 1 clear soda bottle
- Plastic roof flashing
- 2 eyebolts
- Duct tape
- Mylar space blanket
- Drill two small holes on opposite sides of the plastic flashing, and thread the eyebolts in the holes
- Fill the bottle with water, leaving enough space that you can add about a ¼ cup of bleach to keep anything from growing in the water.
- Cut the mylar blanket into a strip approximately 1/3 the height of the bottle.
- Center the mylar strip in the middle of the bottle and wrap it tightly – you need to leave unwrapped bottle at the top of the bottle to gather light, and at the bottom to release it. – Basically you are making a reflective tube to channel the light.
- Insert the bottle into the flashing, leaving about 1/3 of the bottle sticking outside the top of the flashing.
- Wrap wire around one eye bolt, pull the wire tight over the bottom of the bottle, and then secure it to the other eye bolt – this keeps the bottle from dropping out of the flashing.
- Insert the entire assembly on your roof and calk as needed to prevent leaks.
Over time UV light will degrade the plastic – but since soda bottles are everywhere, it is a simple process to rebuild as needed.