Passive Solar Hot Water

Build Your Own Solar Water Heater

Build Your Own Solar Water Heater

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Kathleen Jarschke-Schultze KB6MPI

My husband and I live on the Salmon River in very rural Siskiyou County, Northern California. Our cabin is about half way between two of the three historic mining communities located on the river. All three towns and the mountainous areas surrounding them are off the power grid. We use primarily microhydro and are now incorporating solar into our system. In the past we've heated our house and water with wood. There are portions of each summer here when high fire danger allows no stove fires. You can't even use a chainsaw in the woods then. Just because we can't have stove fires doesn't mean we can't have hot water. Supplementing our wood stove heated water system we added an amazingly simple passive solar water heater.

Materials Needed

• one 4 ft. X 4 ft. square piece of 1/2" plywood

• roll of clear plastic

• plumbing fittings to hook into your water tank

• one 5 1/2 in. X 5 1/2 in. square of 1/2" plywood

• 4 square feet of aluminum litho press sheets

• four 3 foot lengths of baling wire

• pipe insulation

Design and construction of this heater are simple. Use the materials you have on hand.

It's the IDEA that counts. In order to get an idea of amounts and lengths needed, I am giving you the measurements of our solar water heater. But, remember, this system is very easy and adaptable to your space, materials and needs. So have fun.


The base is made up of four 4 ft. long 2" by 2" nailed into a square. This is covered by a 4 ft. square piece of 1/2" plywood, covered with shiny aluminum litho press sheets, available for most printers or newspapers . Aluminum foil will also work, but litho sheets last more than one season. Slightly in from the edges (1-2") are four 43" long 2" by 2"'s cut at a 45° angle on both ends, see diagram, attached in a pyramid shape and affixed to a 5 1/2" square of plywood at the top. Nail a 6p nail into each 2" by 2" about 3" up from the bottom. Here is where the obligatory baling wire comes in. Twist the end of a length to each nail, then start coiling the PVC pipe around the bottom of the pyramid resting on the protruding nails. When you have four coils of PVC, place a nail on each 2" by 2" directly above the last coil. Pull the baling wire up tightly and wrap it around the nail to make the coils firm against the pyramid (see diagram). Continue this coiling and securing 'til you reach the top square of plywood. It would be best if the PVC then extended unbroken to the metal intake atop the water tank. Location

Place the pyramid as close to your water tank as possible while still allowing full southern exposure. The top of the pyramid must be lower than the top of the tank and the bottom of the pyramid must be the same height or lower than the bottom of the tank (see diagram). For maximum efficiency insulate the top pipe from the pyramid to the tank. Make sure the pyramid platform is level. Our system has a ball valve in the top pipe where it changes to metal pipe to enter the tank. This enables us to shut off the system in the evening to keep the hot water from recirculating and cooling. Also the hose and ball valve from the bottom of the tank to the PVC at the bottom of the pyramid allows us to turn off the valve, unhook the hose and drain the system for winter. The finishing touch is to cover the outside of the pyramid with clear plastic and staple it down. We have to replace the plastic every year, as it deteriorates in one season's use. Conclusion

On a summer's day we get about 10 gallons of very hot water. It helps if, in the morning, you run the hot water faucet for a minute to get the flow going good. In building this system you can really let your homesteading adaptability come into play. My friend Sarah, who did the diagrams for this article, and I built a pyramid for her house. Utilizing materials we could find there, we substituted 2" by 4" for the 2" by 2". The only practical space to place the pyramid was a 66" by 30" space, right off her deck, so the unit became rectangle. To increase efficiency we placed a reflective backplate behind the pyramid to gather more solar radiation. The more black PVC you can get on your pyramid, the more hot water you will have. Within a few basic rules this design is limited only by your needs and imagination.

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Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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