Instructables

Complete Steps for Building A Solar Thermal Soda/Beer Can Heater for A Greenhouse

video Complete Steps for Building A Solar Thermal Soda/Beer Can Heater for A Greenhouse
I needed a way to add free heat to my greenhouse. I am growing cool weather vegetables like lettuce, spinach, cabbage and kale. They can take a light frost. My goal is to keep the greenhouse producing through January. Yes... freezing days and nights in my gardening  zone, zone 7.

This videos shows you every step of the build from supplies and cost, all they way to sealing the plexi-glass to the frame. Here is what you will see:

1. All the parts and costs
2. How to drill, seal and stack the cans
3. How to build the box
4. How to paint and arrange the cans
5. How to seal the glass

The  video will teach everything you need to know to build one yourself. You can make them as large as you wish. If you build a large scale design you will need to use wood for the frame backing.

Link to my blog entry with videos that show output heat tests of over 140 degrees.

The principle is pretty simple. Cool air comes in from the bottom. It is heated nicely as it travels up the cans. It is released back into the greenhouse from the top of the unit. Nature creates a natural current. Heat rises and moves upward creating a current that draws in cool air. This is a small scale model for my needs. Some solar heaters use over 200 cans in columns of 25+. They are used for heating rooms. This design is just for a small greenhouse.
diy_bloke11 days ago

i have been doing this too and at a certain moment i wondered if the beer cans were really necessary... if maybe just a black box would do the same. after all the surface gets a set amount of energy from the sun. beercans are not going to increase that amount, so i really wonder