Solar shower project

I’ve been planning a solar shower since July, but since then it has always been a second-priority project, and with the garden in full swing and plenty of summer events I didn’t have time to work on it until now.  I got the panel for free from my off-grid friends Jesse and Eva, who got it from a hoarder but couldn’t make use of it in their cloudy valley.  The tank is our old well pressure tank, left on the property when the landlords removed it four years ago.  The pump was found on Craigslist for $15; it had a stuck shaft but was easily fixed.  Despite all of that cheapness the project total still came to around $400-$500 with insulation, plumbing, and supplies for my panel mount.

Panel aimed at the setting sun

Inside the panel water flows upward through parallel copper pipes encased by the black sunlight-absorbing aluminum fins.  The two faucets on the wall are the hot and cold for the shower.  Actually building the shower will be my next project…

Dual-axis adjustable panel mount

I wanted to be able to both tilt the panel and rotate it to face the sun.  Ideally this would be done automatically, but dual-axis tracking systems are well out of my budget.  So I settled for this design of my own imagination.  The 1 5/8″ post is sunk almost four feet into the ground, but with the 100 lb panel it is still a bit shaky.  I may add angle braces or pour some concrete around the base.

Plumbing inside the barn

The plumbing is all done with PEX plastic pipe, which is becoming the new standard for home plumbing.  It is freeze tolerant and can withstand temperatures up to 200 degrees, which is what I needed for this system.  The shutoff and filter in the foreground will be enclosed in an insulated box to prevent freezing.

Tank, pump (blue), and mixing valve (upper right) inside a very well-insulated box.

The box is built from 2×6’s and pressboard that were lying around the property.  It is insulated with R-19 fiberglass and lined with reflective insulation, for an estimated R-value close to 30. Cold water enters at bottom right when hot water is used.  Otherwise the water flows in a loop, out of the tank at the bottom, through the pump and out to the panel, and back into the tank at the top.  At the upper right is a thermostatic mixing valve, at $74 the most expensive part of the system.  When the tank exceeds 115 degrees (which will be common in the summer), it mixes in cold water to keep the output at 115 degrees and prevent scalding water from reaching the shower.

95 degrees - almost warm enough for a shower

This remote thermometer has a five-foot capillary tube and is inserted into a thermowell in the back of the tank.  Today the temperature rose from 70 to 95 degrees – not as much as I might have hoped for.  With the low winter sun our tall apple tree shades the panel for 2+ hours in the afternoon.

My bedroom has been smelling a bit musty lately, and I looked behind my dresser today to discover this solid coating of gray mold.  I sprayed it down with 50% bleach and it is now sitting outside our front door de-bleaching.

Unwanted fungus!

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