Passive Solar Water Heater/Shower

Oh boy, here goes another  dense, boring how-to post, you think. Great. Why can’t we have more stories about your ex, or Renaissance faires, or something cool and fun? But bear with me here, because I’m about to show you how to build your own solar shower. And there’s PICTURES! Even one of me demonstrating the shower! (Sorry, it’s pretty g-rated.) The instructions given here will help even the most distractible person with zero plumbing knowledge (that’s me!) build a working solar shower. A shower built with the dimensions specified will hold about 7.5 gallons of water, enough for a decent shower including washing your hair. It won’t get hot, but it will get warm enough to be nice on a cooler summer night.

But wait, excited readers, before you get started you will need some tools and materials. Tools for this are pretty simple: you will need a power drill with a 1 1/2″ hole saw bit and a star bit for driving screws, an adjustable wrench, pencil or other marking tool, 60-grit sandpaper, channel lock pliers that will accommodate a 3″ object, and I think that’s it. For materials, you will need:

10′ section of 4″ diameter ABS pipe (the black plastic stuff)

1 1/2″ ABS female adapter

1 1/2″ ABS cleanout plug

2 4″ rubber end caps for pipes

Metal pipe hanger strapping– you can also buy this as individual pipe hangers with a loop for the pipe to go through and a screw to hold the loop shut, I recommend getting them in this form but can’t find the right part on the Home Depot website.

3/4″ bulkhead fitting (ABS, of course. This might take some searching around.)

6-10″ garden hose (don’t just cut a length from a longer one, make sure it has the adapters on both ends.)

8  1-1/2″ self-tapping screws

Dramm sprinkler head and shut-off valve (product #10-12365 and #10-12349 in their catalogue.) Don’t try to use another type of sprinkler head-this works best for low water pressure.

Nice big tube of flexible watertight caulk (I used Through The Roof) and caulk gun

Roll of pipe thread sealing tape

Can of ABS glue (do NOT use glue designed for PVC pipes!)

 

Ok, first order of business is figuring out where to hang your water heater. Choose a location that will get lots of sun during the day, and provides a mounting point at least 8′ off the ground. Now, you’re going to make a hole for the fill cap. SLOWLY drill a 1 1/2″ hole in one end of the pipe with the hole saw; if the drill bogs down in the plastic, just back off a little. Clean up the edges of the hole with sandpaper to remove little plastic shreddies. Now, put the female adapter over the hole-this is going to be your fill hole. See how it doesn’t sit flush over the hole? We’re getting to that. Now, wrap the sandpaper over the pipe with the gritty part facing up. You’re going to run the female adapter over the sandpaper until you sand enough of a curve into it that it sits flush over the pipe. When that’s done, put it over the hole you drilled, making sure there’s no gaps between the adapter and the pipe. Now, glue the adapter over the hole, using the ABS glue. Make sure to carefully follow the instructions on the bottle-that stuff sets FAST! Also it’s quite toxic, so keep kids and pets out of the way. Once it sets up, paint a thin layer of glue on the outside of the joint. Let dry undisturbed. Once this is done, screw the plug into the adapter-you now have a filler cap. IMG_20160717_145815282_HDR

You’ll end up with…this.

Now it’s time to assemble the hose end. Screw the shutoff valve and sprinkler head together, then attach them to the hose. Unscrew the two halves of the bulkhead fitting. The sticking-out bit (for lack of a better word) that screws into the round bit will be the part that passes through the rubber cap. place this part towards the bottom of the rubber end cap, trace around it, and cut a hole for it with a sharp knife-make the hole slightly smaller than the fitting. Push the fitting through the cap so the threaded part is on the outside. The hexagonal bit should be on the inside. Also note: there are two gaskets in the fitting, make sure one goes inside and the other goes outside! Tighten the bulkhead fitting as much as you can-you may have to grip one side with the channel-lock pliers and turn the other part. It’s threaded backwards, so turn left to tighten and right to loosen. When the fitting is tight as it can go, run a bead of sealer around the edge, between the fitting and the cap. You will probably need an adapter to attach the hose to the bulkhead fitting; take both parts into a hardware store and they should be able to tell you what part you need. Put pipe thread sealer tape on the threads of the fitting and the end of the hose. Then, take the rubber cap and put it on the end of the pipe, tightening the bolt on the little metal band around it as much as possible. Once it’s all attached together it should look like this-

IMG_20160717_145728232_HDR

Put the other cap on the filler end of the pipe, tightening the metal band with the adjusting bolt as far as it will go. You’re now ready to hang up your solar shower. Put the 4 pipe hangers in place around the pipe. Next, mark off where you’ll hang the heater. You’ll need it to be at least 7-8′ off the ground to get a good flow. You will also need to hang it at a slant. Mark off the position for the fill end 3-4″ higher than the drain end. Space the pipe hangers out evenly, making sure they have a solid support to go into, like joists or a trailer frame. Line up each hanger over a support, and mark out spots for 2 screws in each hanger, marking through the holes in the hangers with a pen or pencil. If you’re putting this on a trailer, line each hanger up with the metal bars that make up the frame. Next, take the heater down, and drill pilot holes for screws. Put the heater back up, making sure the hangers are lined up right. Rotate the pipe so the fill cap is facing up and the bulkhead fitting/drain is facing down. Have someone hold the heater up for you while you drive the screws in. Don’t let go until you’re sure the pipe will stay put! IMG_20160717_145831834_HDR

(I actually attached mine to the roof. If you do this, put a bead of sealer around the screws to avoid leaks.)

 

Congratulations, you now have a solar water heater! You can fill it with a bucket and a funnel, or run a garden hose directly into the filler cap. IMG_20160717_145928590_HDR

And here’s the shower in action! Happy summer, everyone!

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