How to Build Solar Water Heater?
1. Poke two holes in the box at opposite ends of one side. Make them the size of the tubing you will use. Glue aluminium foil on the inside of the box and paint the foil black.
2. Insert tubing through one hole and curl it around the bottom of the box. Poke the tubing out the hole at the other end. Leave roughly equal amounts of tubing sticking out of both ends of the box.
3. Paint the tubing inside the box completely black.
4. If the tubing does not stay at the bottom of the box, pin it down. Do this by bending a paper clip around the tubing and sticking its ends through the bottom of the box. Bend the clip ends on the other side, clamping the tubing down.
5. Tape a thermometer to the bottom of the box.
6. Cover the box with plastic wrap, glass, or Plexiglas. Tape it on so that it is airtight. If you use plastic wrap, stretch it so that there are no wrinkles.
7. If the buckets you use do not have tops, make tops out of cardboard. Insulate the buckets by taping sheets of newspaper around them. Poke two holes in the top of one of the buckets for the tubing. This is your experiment bucket. The other bucket will be your control.
8. Fill both buckets with water. Insert tubing in your experiment bucket. Make sure that one end of the tubing is near the top, the other at the bottom. You may need to cut off some excess tubing to do this.
9. Prop up the box at a slant so that it is facing the sunlight (its shadow should be directly behind it). Place the experiment bucket on some support (books or another box will work), so that it is completely above the level of the collector. Arrange the control bucket at the same level.
10.Suck on one end of the tubing in the control bucket to fi ll the water pipe with water. Make sure there is no air in the pipe when you insert it back in the water.
11.Leave the solar heater and control bucket out in the sun for 3-4 hours and measure the temperature of the water periodically, as well as the temperature inside the heater.