The first commercial installation of a hybrid solar thermal-natural gas water heating system now is in use.

Originally designed for residential use, the system is also an efficient hot water delivery system for industrial and commercial applications up to 195°F (90.5°C). "What makes this system attractive for commercial applications is that you can ‘gang’ the tanks up to a quantity of eight, offering the potential to supply a vast amount of hot water to particular applications," says David Cygan, the Gas Technology Institute's industrial R&D and solar program manager.

GTI, headquartered in Des Plaines, Ill., with its manufacturing partner Solar Usage Now, Hamilton, Ind., installed the Sun Equinox system at the Samuel Billings Center, a county-owned building in Charlotte, N.C.

The installation includes two tanks, each with a 132-gal capacity and five solar collectors. The installation replaced a 100-gal water heater, giving the building more capacity. The tanks are polyethylene, "which can easily last 25 years or more," Cygan says, noting that the system has the potential to deliver energy cost savings of 40 percent and a corresponding reduction in greenhouse gases.

"It’s very cost-effective," says Thom Blake, president of Solar Usage Now. "Everything on the system is assembled and ready to snap into place, limiting expensive labor costs."

Natural gas is the cleanest-burning fossil fuel, which makes it an ideal complement to solar and wind, which is available only intermittently, GTI says. Pairing natural gas with renewable energy sources represents a real opportunity to move toward more environmentally friendly energy sources.

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