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Solar Hot Water Shower

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.

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.

copper pipe, solar hot water, corrugated iron panel

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.

outhouse, solar hot water panel, homemade

Finished solar hot water shower and sink.

Reciprocal Roof

What is a reciprocal roof?

Reciprocal Frame Architecture by Olga Popovic Larsen

‘Reciprocal frames consist of linear members which are mutually supported and interlocking, forming either a flat, horizontal structure or a pitched three dimensional frame system.
The simplest form of a reciprocal frame is a beam system arranged around a single, central circle.
Each member is supported at the outer end by a ring, beam or column and at the inner end is supported by the adjacent member. When reciprocal frame members are arranged regularly around a central point of symmetry we get a regular reciprocal frame structure.’

We were lucky enough to be able to go into Circle Organics’ woodland and find logs we could use for the rafters of our reciprocal roof.  An octagon was build on the top of our square outhouse to accommodate eight rafters, as we wanted our roof to be round.

The octagonal frame to support our rafters.

The octagonal frame to support our rafters.

Once we had sourced our rafters, that were as straight as possible and 11′ long, we had the tricky task of pulling them up on the roof and positioning them. Firstly we placed some supporting rafters to help hold our rafters in place and to make it easier and safer for us.


Positioning our rafters.

All the rafter were placed in position, one end on one point of the octagon and the other end in the centre. Each rafter rested on the previous one and they were tied together with twine. We used twine so we had some flexibility to tweak the rafters in place and to make sure they were supporting each other and that we had our desired shape. Once we were satisfied we screwed them together and the twine was cut.

We then used slab wood for sheathing the roof to create a sturdy platform that we will put straw bales and soil on to make a living green roof.

slab roof, reciprocal roof, green roof

The slab wood sheathing.




We have been building an outhouse that includes a composting toilet and solar hot water shower for the farm so that interns working and staying there will be able to use if for years to come.
The outhouse has been built mainly from pallets and any other material we could find to up cycle rather than buy. To separate the shower from the toilet we are building a cord wood wall and using tin cans and slab wood for siding on the outside wall. We bought a second hand sink and have hooked it up to the solar hot water.
For the roof we decided to build a reciprocal roof and plant a green roof on top of it.




Studying hard and getting to grips with building science!