Carl came up with this very simple and effective solar batch heater that heats up one bucket of water. You put the 5 gallon bucket into the glazed box, put it in the sun, wait a few hours, and then take the heated bucket of water to where you need it.
Perfect for a cabin, emergencies or just locations without running hot water.
Thanks to Carl for providing this!
From Carl:
I placed it on the wheeled base shown and aimed it a couple of times a day.
I made a foam insert to place in the top of the bucket and threw a blanket over it to retain the heat. This kept the water warm about 9 pm.
Camping, camp, cabin. For any primitive area needing warm water, this is a very simple way to get it.
With only labor and simple materials, this is easy to scale up in size. Build a box for 3 buckets,or a long one on a south wall for many buckets.
The essence of this is a batch heater that you carry to the bathing area and use. I scooped the water out with a 32 oz. plastic cup and poured it over myself. 4 gallons was always enough to bathe with.
Click images for full size
Performance
Test day: May 21, 2014 -- a sunny clear day.
11 am
Placed 37 lbs of water at 53F in the box.
Ambient temperature 72F, clear skies
Midday
Clear skies with an ambient high of 85F.
6 pm
Stopped
Ambient temperature 84F
Water in bucket 122F
Warning
Be very careful when handling or using the hot water -- it can be very hot, and will require tempering with cooler water for a shower.
Rough Plans
In one of the comments below, Nicole requested a rough plan and list of materials. The sketches below are a rough cut at this based on the photos that Carl supplied. So, these are not the actual dimensions that Carl used, but they are fairly close, and the dimensions are not that critical.
The first sketch shows a cut diagram for all of the sides, front, back and bottom -- and a cut size for the glazing.
This sketch shows a top view (looking down) on the assembled enclosure.
The wood strips in the corners, which can be about 1 by 1 inch are used to attach the sides to the back and front.
Materials:
For the sides, front, back and bottom you could use half inch plywood.
The glazing could be 1/8 inch thick plexiglass. Lexan (polycarbonate) would be better than Plexiglass, because it holds up to higher temperatures and is tougher, but its also more expensive. For a quick and dirty version, clear polyethylene film could be used and would work nearly as well thermally.
Use yellow wood workers glue to glue the parts together. Drywall screws work fine for attaching the various parts together and are cheap.
Assembly
I'd cut out all the pieces first.
Attach the 1 by 1 strips to the vertical edges of the front and back -- place them 1/2 inch in from the edges of the front and back pieces so the the sides will nest into them. Use yellow glue and 1.25 inch drywall screws.
Attach the sides to the front and back pieces using by screws and glue to the 1 by 1 strips you attached to the front and back in the step just above. You should now have the basic box. Test fit the bucket inside the box to make sure it fits and that the glazing will clear the bucket.
Place the box on the base and center it. Mark the inside edges of the box on the base with a marker.
Add the 1 by 1 attachment strips to the base using the lines you marked in the step above to locate them.
Attach the base to the box using screws, glue and the 1 by 1 strips you added just above.
Attach the glazing stop strips to the glazing. They sould be about 1 inch above the bottom of the glazing. These strips keep the glazing from sliding off the box. The stop strips could be more of the 1 by 1.
If you want the whole assembly to be easy to rotate (to face the sun), you could use a kitchen cabinet lazy susan between the bottom of the box and another piece of plywood that is about the same size as the bottom and sits on the ground.
This is all made to fit around a typical 5 gallon plastic bucket (like the orange ones that Home Depot sells).
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