Basic Principles

If you’ve ever left a garden hose out in the sun before turning it on, you know how easy it is for water to be heated by sunshine. Converting sunlight to electricity is a fairly complicated process, but converting it to heat is a no-brainer.

On the other hand, heating water (or anything else) using electricity or natural gas takes quite a bit of energy (and generates quite a lot of CO2 as a result). Replacing all this heat energy with the free heat we get from the sun makes a lot of sense, not only in terms of cost but in its reduced impact on the environment.

The water heating system I built has two main components:

• Solar Collector: A large surface that is heated by the sun
• Storage Tank: A water tank that stores the accumulated heat

Of course, there’s a little more to it than this, but those account for 90% of the materials and effort. Here’s a diagram showing how it all fits together:

The water in the storage tank is only there for collecting and storing heat; it’s not for drinking! Our potable water flows through a heat exchanger immersed in the tank, picking up some of that heat on its way to our regular electric water heater.

This document will go over the construction of each component. First, the Solar Collector.