Solar shower

After the expansion of the garden recently, I found that pre-cleaning myself prior entering the house was necessary. I used to use tap water for this, but it can be pretty cold in Quebec so I build-up a solar heated outdoor shower with the spare parts from the water system.

The system is made of recycled wood and a piece of Plexiglas that prevents heat from escaping but let the light get in. I have a total 48 rolls of ¼ inch pipe (250 ft long) that are split into two circuit (24 rolls each) to allow a better flow.

The water temperature is controlled with two valves. One for cold (direct water) and the other for the heated water. The water can get pretty hot inside the system but only for a limited time. That is the water stored into the pipes. After a few minutes of direct sunshine exposure the water reached 44 deg. When flowing, the water eventually cools down in two steps. The first one that I called inertial heated water is when the pipes are still hot, but the stored water has been consumed. Finally the last step is the steady state that is when the water is only heated by the sun continuously.

One of my objectives was that the system was small enough to be portable. I was also seeking for an interesting continuous temperature, but not necessary with a high flow.

Here are the measurements I did with the system:

The measurements were done with an outdoor temperature of 27 deg in the shadow and 38 deg under direct sun. The box was slight inclined toward the sun, but not completely facing it and there were a few overcasts. The box as an interior size of 87 cm by 48 cm.

The conclusions are that air increased by 2 deg the water temperature while the sun added another 5 deg to it. In other words, the system also work at tempering the water when there is no sun. At 27 deg the temperature is acceptable for long showers, especially when started with warmer temperature and cooled down gradually. However in most situations I don’t need to reach the continuous flow as I never run it with max flow and always mix the stored water with cold water which make it last for 5 to 10 min. (Especially that when reducing the flow the water have more time to warm up in the pipes.)

If more time is desired (example two peoples) the shower might be stopped for 5 min and water heat-up again to it's maximum temperature.

The only annoying thing is to control the cold water flow when the stored water is exhausted because it creates a significant temperature drop. An automatic system would be nice but I don’t think a passive system exist for such low water flow…

Another nice feature is that it is detachable so that I can focus on my feet or water plants with warm water.

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