The Solator - a solar shower.

Intro: Ever tried a “solar shower” sold cheaply in camping shops? The principle is great and they are light and compact to pack. However, being flimsy, leaks develop … mmm!
The Solator was born/designed from a wish for a more durable DIY unit, using materials readily available.

Principle: Sunlight is absorbed best by black surfaces. Water in contact with such surfaces can be heated to useful temperatures for showering. Inner tubes (for vehicles) are durable, non-corroding and foldable. However they tend to be grey – not black – due to chalk-dust coating. To improve absorption, the sunny side was lightly sprayed black (this may help protect tube from UV attack). (To improve insulation, the bottom surface could be silver painted.)
Water volume within the “toroid” shape can be calculated from V=2.π.π (r.r+ R), where V is the water volume in liters, r is radius of tube cross-section (cms) and R is the mean radius of the tube (cms).

Materials Needed: a 14" inner truck/vannette tube (s/h patched ones may still have useful life). This contains approx. 27lts water.
Shower head (plastic) – not essential
Flexible plastic tubing – 10mmØ x say 1m.
Garden hosepipe ½" with tap connector (suited)
Tank connector ½" (plastic was used)
Ball valve ½" with ½" female ends
½” BSP - ½ push-on hose connector (plastic)
Thick (3mm) plastic sheet to cut out washers

To Make: Make 2 plastic washers to fit tank connector with, say, 10mm extra outer radius. These clamp the rubber tube to seal it. Carefully cut a smaller diam hole in outer diameter of tube (suggest on side with valve but back-to-back). Carefully push tank connector and one plastic washer through cut hole (a second model had a 50mm diam repair patch fitted to the connector site). Assemble then fit tank connector facing outward with 2nd washer then nut on outer side. The old valve stem may be removed and patch applied to that spot (left in on prototype). Ball valve and hose connector can be fitted.

To use: Unit only operates in sunshine.
Fit garden hose and fill from tap (or funnel), ensuring ball-valve first open! Fill till tube takes full, un-stretched shape. Remove hose. Positioning ball-valve uppermost, “crack” valve open to remove all air from inside tube (air prevents heat conducting from rubber wall to the water within – tube gets very hot but water remains cold!).
Position tube:
· on a slope outdoors preferably where
· the sun lingers long,
· out of the wind and
· on an insulated surface e.g. closed-cell bubble-wrap/foam to prevent heat transfer through the underside.
We sat the tube on a bubble-wrap sheet in a wheelbarrow and propped it up at the front end. This encouraged thermal siphoning to bring cooler water in contact with heating surfaces.
Showers need to be taken late afternoon/early evening (i.e. soon after sundown) since black surfaces radiate rapidly back into the atmosphere (a down side of black!). A good method of reducing/delaying this loss is to cover the unit at 5pm with a blanket until bathing.
A satisfactory means of supporting the unit whilst showering has yet to be found. The best so far is merely to balance the tube on a tree branch some 30cm above head-height at the shower site. Fit the tube and rose. Pressure and flow-rate is sufficient for most needs. Temp cannot be regulated, hence care is needed if water temp exceeds 50oC. Two or 3 persons may enjoy adequate showers from one tube.
In Practice: Setting the Solator out mid-morning, we found that 50C+ was reliably reached by 4pm, provided that the sun shone most of the time. Clouds kill the heating – in fact, the tube cooled in shade. With clear skies, we managed 68C one day – too hot to use. Blacking the top surface does improve heat absorption but a durable paint has yet to be found.
A simple slatted base was knocked together from pine strips to keep feet clear of the muddy ground.
Conclusion: The Solator seems to be a cheap, innovative and practical unit for shower water heating in sunny locations.
We wish you success in your solar shower unit!

This leaflet is produced by a non-profiting individual wishing to promote solar water heating systems.
For further info, contact:

P.O. Box 20241, KITWE, Zambia.
dustybushtech@gmail.com
The earth is the LORD’s, and the fullness thereof; the world,
and they that dwell therein. Ps 24:1

***** Aug 10
May 2019
The test of an innovation is whether or not it is still in use. I'm on the 5th tube. My wife and I continue to shower daily when the sun shines. Several visitors have tried it out - enthusiastically. 2019