Shower Power

download the ppt presentation

For our kinetic energy project for Sustainable Energy, Rory and I tried to find a way to harness water power from shower drains to charge rechargeable batteries. In the end, we had to come up with alternative applications for the energy we tapped into, but we had some limited success. Our process and discoveries follow.

Since we don't plan to destroy anyone's actual drainpipes (and it would be difficult to present our project in class if we did) we're simulating a bathtub/shower and drain with our handy tupperware box.

It looks nice now, but you should know that it was a ridiculous pain to get the drain installed in this container. I poked a small hole in the bottom with a dremmel, then used a circular blade to widen the hole, and then used a sanding bit to smooth and further widen the hole. Everything was going well until I was pushing the drain through the hole. I pushed a bit too hard, and the plastic cracked along the bottom. *#($*!$%. Luckily, it doesn't appear to be a major problem - water hasn't leaked through it (so far).

While I was working on installing the shower drain, Rory was doing motor testing and rigging up the fan blades to turn the motor. He modified some fan blades he got at the ghetto motor store to "catch" the water. (See the before and after pictures below.)



The next major challenge was lengthening the motor's shaft so that we could insert the fan blade partway into the PVC pipe but still keep the motor itself outside of the pipe (and hopefully dry).

Once our mini-turbine was ready, we had to install it in the pipe. Rory took a Dremmel to the pipe and cut out a rectangular area in which we mounted the turbine. We attached the breadboard and were ready for user testing. We began with simply turning the fan blade manually (no water) and successfully lit the led. See the video below -- it's exciting.

In stage 2 of user testing, we took our creation into the women's bathroom and filled our "bathtub" with water. We pulled the plug, and BAM! Nothing really happened. We discovered several things -- one, the pipe was too large in diameter. We weren't able to send enough water through the pipe to turn the turbine just by accumulating about a gallon in the tupperware container. Two, our turbine wasn't in exactly the right position to catch the water flow and turn effectively. Three, having a rectangular hole cut out of your pipe facilitates water spilling everywhere.

How powerful is this?

Our open current voltage = 15-20V with a maximum of 35V. Our closed circuit current is 2-2.5mA.