Solar Hot Water System
Our outdoor shower makes excellent use of a handmade solar hot water system. This is a simple system that will supply hot water to the shower and also to a sink on the outside of the outhouse.
The System in a Nutshell
Designed minimally and for warmer weather, the water supply comes from the house via a hose line and into the outhouse. The main supply line connects to PEX piping and splits off at the shower and again at the sink to supply cold water. The remaining line goes into a hot water tank that rests above a handmade solar hot water panel. From the tank the water comes out and into the panel where it is heated by the sun. The water exits the panel and travels back into the tank from which it is then drawn through pipe to the sink and shower for hot water use.Our shower floor consists of large flagstone slab with a drainage bed of gravel to fist sized rocks directly beneath the slab. The drainage bed leads down a shallow dug trench and into a small pit filled with rocks.
Thermo-siphon
When hot water is not being drawn from the system, a natural thermo-siphoning occurs within the panel and the tank. Hot water that is running through the panel will enter the tank hotter than the water that is filling the tank volume. That forces the slightly cooler water to exit the tank and run back down into the panel. And so the cycle continues.
The Panel
The solar hot water panel that we made is incredibly simple and is very low cost.
A shallow plywood box topped with a piece of tempered glass from an old patio door houses the piping.
Water will run through a network of vertical pipes connected by horizontal pipes at the top and bottom.
Once the water runs through, it exits at the bottom of the panel from a pipe split off of the rest. Corrugated metal roofing that is typically used for barns makes a great housing for the piping itself. This roofing is painted black and then fastened into the bottom of the panel box. Corrugations that are a half circle shape hold half inch copper pipe very well.
Building the solar panel.
By resting the pipe in the half circles, there is much more of the pipe in contact with the metal than if it rested on a flat sheet of metal. This is a great benefit because heat is conducted through the metal roofing and into the pipes. As the pipes heat more and more, so does the water that runs through them.
Finished solar hot water shower and sink.
