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DIY Solar Panels

An Interview with Scott Davis

We're forever discussing the merits of solar panels, in terms of getting them installed for you. A lot of people see them as a complicated technology that they'd be terrified to consider building themselves! Whilst certainly the latest mass-produced solar panels are produced from top of the range materials, the theory behind solar panels is really quite simple and there is a rising online community of DIY solar enthusiasts, keen to cut their bills. This week, I got in touch with Scott Davis, whose list of projects include a 24 foot by 8 foot ground mounted collector for solar hot water, and for solar winter space heating in his garden, as well as a solar hot air collector which drives hot air into his basement.

Source: (Scott's homepage)

Scott very kindly took the time out of his schedule to answer a few questions for us, and we hope this may encourage a few of you to take up this as a new hobby - see Scott's email group for a bit of info to get you started. Right, on with the questions:

Hello! People often think of solar panels as something full of complicated cutting-edge technology. Is this the case?

Oh, no, at least it doesn't have to be. Highly efficient collectors can easily be built with nothing more complicated than window screen and an insulated wooden box!

One of the really exciting aspects of solar heating technology is that it is both elegantly simple, something anyone who can pick up a hand saw and drill can enjoy, while also being ripe for experimentation and technological advancement by the backyard hobbyist / experimenter / inventor.

The basics of solar are simple. When the sun shines on things they get hot. If the material is black, it absorbs more of the sun's energy and gets even hotter. If the black material is insulated under a clear glazing such as glass, Plexiglas, polycarbonate, etc., it gets REALLY hot, even in the dead of winter! All we are doing is retrieving the heat that the sun freely provides daily, using air or liquid to pull the heat off of the hot material in our collectors and transport it to a place where we need it.

That said, while the basics of solar are simple and have been around for a millennia, I am completely amazed, astounded really, at how much there is still to learn about DIY solar. Just last winter, Gary of and I did some side by side testing of some common hot air collector designs and we were amazed at the variations in performance. One of the exciting results is that one of the best, highest performing designs is also the cheapest and least complicated to construct - something anyone can do!

Solar is such an interesting, inexpensive and useful endeavor, I would have thought the things we are experimenting with now would have been fleshed out decades ago. The really great news is the fun, thrill and satisfaction of making those discoveries is left for us! Ask yourself, what other opportunities can you think of that the average person, with no particular construction skills or science background, can inexpensively, meaningfully participate in, that has the impact of what we are doing? We have the opportunity to help folks heat their homes with clean, free energy, provided courtesy of the sun, for a lifetime!

How did you get into these solar energy projects? Did you have a lot of DIY experience?

I manage an office and write software for a living. I sit in front of a PC all day, so I got into solar with virtually no DIY experience. In fact, thinking about solar projects is so different from the rest of my daily responsibilities, it is a truly pleasant and rejuvenating diversion. But no, I had almost no DIY / hands on building experience at all when I began.

I know a lot of folks start out in solar to save money, which obviously is another great aspect of the hobby, but that wasn't the main motivation for me. I got into solar because I love nature and taking care of our precious planet. I've always had an interest in science, solar is extremely interesting, it's really fun to try experiments and it is just such an obvious part of the energy solution!

You built several solar projects, including a downspout hot air solar collector - It looks like a brilliant idea! Could you very briefly describe what this solar collector system does?

You bet. This is a low profile, neighborhood friendly collector, only 13 inches high and 24 feet long, that can barely be noticed from the road. This collector is nothing more than aluminum downspouts that you find at your local hardware store, connected in a loop, painted black and put under Plexiglass glazing. There is a snap switch in the collector that turns on a fan when the collector reaches 110F. For hours every sunny day, this simple system pulls the coldest air off the floor, circulates it through the downspouts, where it heats up freely and cleanly, courtesy of the sun and then returns it to our living space for us to enjoy.

When you installed electric solar panels on your roof, what was the most difficult part of the project?

I am most enthused about solar heat, since that can be done inexpensively, safely and easily by anyone. With solar electric, you've got to do it right or bad things can happen. Fortunately, I had wonderful assistance from my friend Dave who helped me through the difficult parts of determining the right components, wire sizes, circuit layout, etc. I would encourage anyone to set up a solar heating system, but for solar electric, if you don't know what you are doing, definitely partner with someone who does.

Have you ever worked out how much you're saving with solar, in terms of money or carbon dioxide emissions?

Honestly, no, I'm much more interested in focusing on different hot air and hot water collector designs, ways to build collectors inexpensively and easily that perform well. The payback for solar heat is a lot quicker than solar electric. If pressed for a number, I would guess I've reduced my heating costs by 30% to 40%, maybe more, but that doesn't tell the whole story. There is a quality / comfort component that doesn't show up in those numbers. We have our conventional heat set at 67F. On sunny winter days, our house will reach the low 70s by solar alone, so we are enjoying more warmth than we would have otherwise if we were just running conventional heat. There is also the quality add of the really nice, under floor radiant heat that I'm using to distribute the heat from my hydronic pex and CPVC collectors. A lot of folks consider warm feet in the dead of winter priceless!

Have you ever thought of any other renewable DIY projects like wind for electricity? Do you have any solar plans in the pipeline?

Wind was actually my first area of solar interest. Unfortunately, the prevailing winds here are from the west and we have woods directly to the west of us, so that's not an option at my house.

I am continually brainstorming ways to easily collect and distribute solar heat that anyone, regardless of DIY experience can build. Just a few weeks ago, my son Brad and I built this CPVC collector [edit: see video below], which is super cheap to build and is working great! Most copper collectors have 6 inch spacing of risers, but because CPVC is so cheap, building a collector with 3 inch spacing works out fine. Even though copper is much more thermally conductive, the extra CPVC risers seem to be overcoming that difference and this collector is definitely a great, easy, inexpensive project that anyone can build. No soldering required - all you need is CPVC, a hand saw, some aluminum flashing and some caulk. I plan to continue to experiment with both hot air and hot water collectors with experiments like this one.

By the way, I should add that building solar collectors is a great family pastime. I've had the help of my entire family on various projects here and we've had a ball.

I've seen you have an email group here - do you think solar is becoming more popular, and if so, why?

Oh, yes, solar is definitely becoming more popular and there are lots of reasons. Folks are becoming more educated on how we are affecting our planet, energy issues and this is one area where we each can genuinely make a difference. Building solar projects gives us the opportunity to stay warmer, save money, think, learn, brainstorm, connect with others who share our interest and enjoy first hand, the fruits of our time spent on our solar hobby. There is nothing quite like feeling the free hot air blowing out of our collectors across our hands, heating our homes or taking a hot shower with water heated by our projects! Our solar projects will continue to give us that wonderful return for decades. Building solar projects is a fun hobby that takes care of our planet and pays us too!

I think that DIY solar in particular will grow strongly for a long time and there is a simple reason for that. Collectors are easy and inexpensive to make, but cost a lot to ship. What's more, commercial collector manufacturers have the added expense of facilities, overhead, salaries, benefits, etc., that all adds to the costs of the units they sell. I understand that In many cases, the cost to ship a collector alone is more than the entire cost of the collector that we can build ourselves. Plus, we have the fun and satisfaction of doing it! There is just no way that the commercial manufacturers are going to overcome the sensible economics, as well as the other great reasons, of doing solar ourselves.

I'm really glad you mentioned our e-mail group! I'd like to invite anyone who is excited about DIY solar, wants to learn more and would like to share this great hobby with others to join our e-mail group, SimplySolar. We are learning a lot, sharing our experiments / experiences, eager to help new folks and would love for you to be a part of our group!

Thanks again Scott!