Achimedes & His Friendly Sun Powered Deathray

As the story goes... in 114BC Archimedes used solar death rays to destroy enemy Roman ships that dared to sail too close to the Syracuse by focusing the rays of the sun using a series of giant mirrors. It's true! They even proved that its possible on Mythbusters, so you know it's legit.

Anyways, we may not be torching enemy vessels with our innovative Simple Drainback design, but we are using the sun's energy with good purpose. And we don't use a complicated series of giant mirrors, either. What do we use? One tank, one pump, and one controller. It's that simple:

The sun begins to heat the collectors, and when the collector's sensor is hotter than the tank, the controller turns on the pump, and solar water is pumped up to the collectors. The solar water is then heated as it passes through the collectors. The solar water then flows down to the tank, and heats the water within the tank. The cooler solar water is pumped from the bottom of the tank back up to the solar collectors. As the solar water continues to circulate, the coiled heat exchanger transfers the heat from the tank to the domestic water within the heat exchanger. The tank sensor will signal when the tank has reached its maximum temperature, and will then turn off the pump. The solar water then drains back from the solar collectors down to the tank.

So when hot water is drawn for domestic use, cold water enters the heat exchanger, an then comes out hot. The hot reservoir continues to supply energy to the domestic line until the stored solar water cools.

Then the sun reheats the tank. When the collector temperature drops below the tank temperature, the pump turns off and the water drains back into the tank. The system then waits again for the sun to heat the collectors.

Check out this simple video demonstrating how it works:  http://simpledrainback.com/simpledrainback.swf

(No Romans were harmed in the making of this video demonstration.)