On June 6, PM attended Viessmann Mfg.’s “Say Hello To Solar” one-day seminar at the company’s Warwick, R.I., training offices, and learned that even though America’s solar market is a "slice-of-a-slice-of-the-pie" compared to the rest of the world, there is huge potential for growth.

“It's an exciting time to be interested in solar,” Viessmann Academy instructor Jim McCarthy told the class of approximately 30 industry professionals, with titles ranging from service tech to business owner, and builder to wholesaler.

Viessmann, which has been in the solar market abroad non-stop since 1978, offers North American professionals two models of solar heat collectors. Attendees of this class were introduced to the Vitosol 100 flat-panel solar collector and the Vitosol 300 evacuated-tube solar collector. Each has its advantages for the application at hand, but primarily they are designed for offsetting the DHW demand for residences and commercial projects.

We were able to see the “guts” of both systems, and McCarthy familiarized the class with the requirements of installing a solar water heating system - such as finding a home’s “solar window” with respect to True South, and determining the collector’s angle of inclination for optimum sunlight exposure. But overall he emphasized “common sense design.”

DHW is a constant load in a home, McCarthy said. Learning how to offset the cost of heating water through solar is a good step toward reducing our eco-footprint, carbon emissions and environmental demand.

“Solar DHW can be used with any existing system. You can retrofit a system with a preheat tank with relative ease,” McCarthy told us. This presents the real opportunity for a contractor. He urged attendees to get comfortable designing and installing the simple preheat systems, since once the process is no longer a challenge, system design gets easier, and prices can come down.

PM will further explore solar heating in the next few months, but in the meantime, here are a few new things we learned:

• The tiny copper pipe inside the Vitosol 300 vacuum tubes work as individual one-pipe steam systems. The energy produced is what heats the solar fluid and thus fuels the DHW.
• Expect a return on investment anywhere from six to 16 years, depending on your geographic location and sun exposure: Southwest customers will see sooner ROI, Northeast a bit later.
• Conceptually, solar is going to give you the most heat when you don’t need it (in the summer months), so be sure to size your system correctly, or design-in a dump zone through controls, such as diverting hot water for pool heating.

 

• Because flow rates required for a solar system are so low, it is relatively easy to make new-construction homes “solar ready.”
• Web sites are available to help determine if your area is ripe for solar: www.retscreen.net aids in system sizing; www.solarpathfinder.com offers solar site analysis; and www.DSIREusa.org helps uncover rebate and tax incentive information in your state.