A Homemade "Factory" Solar Collector

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Is it possible to slash the cost of solar water heating and still retain store-bought quality?

In order for solar technology to be accepted, it must be affordable . . . but while many manufacturers go to great lengths to develop well-designed, functional products, they often fall short of achieving even tolerable cost-effectiveness.

Part of the problem is that a sizable portion of production cost lies in assembly. Many solar enthusiasts are circumventing that built-in thorn by fabricating their own system components, most notably the collector panels.

Understandably enough, though, not all of us have the skills — or the time and inclination — required to design and construct a state-of-the-art solar collector from scratch. However, kit assembly is within the realm of even a novice do-it-yourselfer . . . and, by presenting our experiences with a typical piece-together panel, we'll give you the chance to decide whether this alternative is your cup of tea.

BOUGHT AND BUILT

Strictly speaking, our test collector didn't come delivered as a kit. Instead, it was pieced together from mail-ordered and locally available manufactured parts. Solar Components Corporation, P.O. Box 237, Manchester, NH 03105, proved to be an excellent source of solar energy products, accessible to anyone with a postage stamp; though it's possible to order certain parts directly from the manufacturer, the convenience of shopping by mail from one store can't be overlooked.

By the same token, it's pointless to send away for common items that are available in your local area. A glance at our materials list will allow you to determine which parts are best purchased in your own neighborhood.

Be aware that the panel we built is similar — if not nearly identical — to the flat plate hydronic collectors sold nationally by manufacturers and distributors. Our goal wasn't to make any technical advances, but to reduce costs to "volkspanel" proportions.

It's apparent from our illustration that there's not a whole lot to this project. In fact, aside from cutting the panel frames, the insulation and hardboard, and the glazing — and joining the fintube to the headers — it won't require that you be proficient in any shop skills whatsoever.

Nonetheless, we'll go over some of the finer points so there won't be any surprises when you're surrounded by strips of aluminum and copper. First, the flanged alloy frames come in 13' 4" lengths and have to be miter-cut with a hacksaw to make the collector box. This allows you to make panels of standard sizes — up to 4' X 9' — using two frame rails. For ease of assembly, we chose to use the corner-key design, which fastens together with push-in angled pins.

Our glazing selection was Kalwall Sun-Lite HP ... a high-transmittance, fiberglass-reinforced polymer that's very popular among solar site-builders. Because of this material's .040" thickness, the completed frame required two aluminum-angle supports beneath the plastic to prevent sagging. As an alternative, we'd suggest using a single sheet of double-strength glass cut to fit the finished opening.