Solar Panel Hot Water Heater

Solar Water Heater

This is a solar panel I made with some big glass panels I scrounged.  It measures about 10 feet long by 3 feet wide.  It saves on the propane bill big time, during the summer months.  Sorry for the blurry photo, I used my aging Palm treo 650 camera.  So this is certainly renewable energy, the sun comes up pretty much every morning like clockwork.

Some people talk about disaster readiness, and I’m all for it.  The economy is showing troubling signs etc.  However I consider propane to be an ongoing disaster that started many years ago, and to that end, I do everything I can to minimize use of it.  Natural gas isn’t available in my area, and isn’t that much cheaper than propane here anyway.  In the winter, I have help from my wood stove to heat my domestic hot water.

The way I built this panel is very simple, it’s just a box made of 2×6’s and OSB.  I lined the inside with polyisocyanurate insulation, that’s the ivory colored stuff that usually comes with foil on each side.  Then I painted the inside all flat black.  There is about 110 feet of 3/4″ copper pipe occupying the interior and I could add more, but my source for recycled pipe dried up before I had it filled.

Accumulating tank

The panel circulates by convection into this accumulating tank, which is nothing but a gas water heater that I tapped into the lower drain port for the cold exit.  This accumulator is up in the attic of my house.  I drain it down during the winter.  So here’s how it works, the cold water drops down out of the drain fitting and down a pipe into the bottom of the solar heater, and then the hot water from the heater rises back up and into the hot outlet of the accumulating tank.  There are no pumps, but it works great.  It makes 40 gallons of nice hot water in a typical day.

The black lines you see in the first picture that go up into the eaves of the house are rubber hoses that connect the solar hot water panel to the accumulating tank.  In the picture above, you can see some light on the lower left where the pipes out to the eaves from inside the attic.

When you open the hot water faucet or take a shower, then cold water from the well comes into the cold inlet of the accumulating tank (different from the drain fitting) and then the hot water comes through the plumbing and into the propane fired water heater, which does a tiny amount of work to heat the water the rest of the way up to where its thermostat is set (much less heating to do than icy cold well water).