Here's an Instructable to make a simple, cheap, and energy efficient air conditioner with basic materials, and should cost less than $5. How it works is evaporating water in the
A/C (air-conditioner) pulls heat away, making the inside cold. The fan sucks air through the A/C, making the air cold. The warmer it gets, the more effective this A/C gets.
And it's easy on your wallet!
The materials are:
-popsicle sticks (about 20)
-cooling fan from computer
-solar panel, batteries, or other low voltage power source
-cloth that absorbs well
-hot glue and a glue gun
Step 1: Cooling fan... Meet the popsicle sticks.
You can get cooling fans free from computer repair shops and are in power supplies.
Once you find a suitable one (bigger ther better), stick six popsicle stick like the picture below.
You can trim the round ends with scissors if you want.
Step 2: Dress Up Time!
Now cut a few strips of the cloth that absorbs well (shamwow, towel, burlap...) like one of the pictures below Then cut using scissors four or more popsicle sticks so it's the same size as the base width . Glue the cloth strips onto the cut popsicle sticks. Then glue that on like the main pic. Attach another stick on the opposite side and glue the cloth onto it. The bottom pictures are examples.
Step 3: Dress Up Some More!
Glue another of these together (pic on the bottom). Then stick two popsicle sticks together like the two back ones on the first step. Glue it on like the pic shows and put another stick that's the base width size onto the other side. Streach the cloth across and attach it to the stick.
Step 4: Coveralls
If you have any extra cloth left, glue that on the sides. Remember: the more cloth, the better if there's easy airflow around everything.