This week we are finally getting the solar panels installed that will heat our floors and provide our domestic hot water!
The process began months ago with Andy DeRocher our project manager at Full Spectrum Solar, who designed the system. Full Spectrum always uses Heliodyne panels, which have been made in California since 1976. Mark O’Neal, who has taken Andy’s place, likes them because they have a long track record of good performance, and in 2011, they were redesigned to be even more efficient.
Solar hot water panels work like this:
(1) The panels face the sun and heat the tubes of fluid inside. The panels are insulated on the back and sides to help build and retain the heat, and when there is sufficient heat to be drawn from the solar collectors, a controller automatically activates pumps.
(2) Heated antifreeze fluid is circulated from the collector into the house where its heat is passed through a heat exchanger, transferring the heat to water in a storage tank
(3) The antifreeze is then pumped back to the collector to be reheated. This circulation loop will continue as long as there is heat to be drawn from the collector. There is a sensor on the panels so when the panels are cooler than the water tank it doesn’t circulate.
(4) During times when there is little or no sun, a backup propane boiler will be activated to provide adequate hot water.
Our four solar panels are 4’x10’ each and have been set up at a 60 degree angle to the sun. This angle optimizes solar collection in the winter when we will need the heat the most, and dials down the over production that would exist in the summer if we tilted the panels at a shallower angle.
Though they look like something that could easily be blown over, they’re actually mounted to a very sturdy rack, and they are rated for winds up to 120 mph.
The glass on the front is tempered and can take even tough hail storms. Mark said they had a case a few years ago of a home where they had installed panels on the roof. After a major hail storm, they had to remove the panels to repair damaged the roof. Then they re-installed the perfectly intact panels. (I’ll bet those people wished they had put up more solar panels.)
I stood in front of them today while talking with the installers. It was a sunny day. I put my hand on the surface at the bottom. It was pretty warm. Then I put my hand up about 3 feet. It was too hot to touch.
The best spot to place them on our property was behind the house on the north side. Their position was carefully selected to avoid shade from the house or the woods to the east and involved a little compromise. The sun starts to shine on the top of the array about 8:00am, as soon as it clears the ridge across the narrow valley in front of the house. And it doesn’t hit them fully until about 9 a.m. at this time of year after it has risen above the shade of the house. But from then on, look out! They will catch the rays until the sun sets over the western horizon. That means our 165-gallon hot water tank will be fully charged for the long, cold night.
Our installer said he thought it was preferable to emphasize later, rather than earlier sun because mornings are often a little hazy, which can minimize the sun getting through. In fact we pitched the panels about 10 degrees west of south to maximize the afternoon gain.
Yes, they are huge, black panels, but to me they look like a step toward a sustainable future.
Have you got solar panels, or are you thinking about them?
If now, what is holding you back? Let us know.