Combined heat and power (CHP) engines, which produce electricity and use recovered heat for generating hot water or air, were once available only as large systems to be used in large commercial buildings. Increasingly, though, engine companies are manufacturing “micro” systems for use in homes and smaller commercial buildings. These cogeneration units are known as microCHP systems and run on propane or natural gas.

Regular readers of the Propane Energy Update will recall our coverage of the ecopower microCHP system by Marathon (January 2011 PEU), sized for home use only. A more recent entry-the CP10WN-SPB-by Yanmar America Corp. offers higher output, producing up to 10 kilowatts of electrical output compared to ecopower’s 4.5 kilowatts. The CP10WN-SPB is rated 88 percent efficient and produces 66,000 Btu of thermal energy. It is expected to be commercially available later this year.

While the CP10WN-SPB is new to the United States, a version of it has been used in Japan and other Asian countries for more than 13 years, says George Woodcock, Manager, Energy System Division, of Yanmar America Corp.

“We’ve made some slight modifications to it to meet the U.S. market and get EPA certification,” says Woodcock, adding that it also has a UL 2200 listing for generator use. This means that it has been UL tested at a high level, an important consideration for municipalities and owners of commercial buildings.

MicroCHP systems use an internal combustion engine, most efficiently fueled by propane, to generate heat and turn a small internal electrical generator that produces electricity. All engines produce heat, but a microCHP system captures it and transfers it to a conventional central-air blower for space heating or to a water supply and delivery pipes for use by various appliances and plumbing fixtures.

The Yanmar unit has off-grid capabilities; contributes to the reduction of greenhouse gasses; offers net metering where available; and is the quietest in its class (54 decibels at 3.3 feet). It only needs servicing after 10,000 hours of continuous use, “which means 13 months and three weeks of ‘no touch’ for the customer,” says Woodcock.

The unit is designed for larger homes and commercial establishments “that require both electrical output and hot water, such as nursing homes and Laundromats,” says Woodcock. “Plus, any entity that needs a reliable power source such as police and fire stations.

“Cogeneration is old technology,” Woodcock adds. “What’s new is applying it on a small scale. We’ve got customers who want that.”

Check out the New Technology area of this site to learn more about CHP systems. And stay tuned for an online training course about CHP systems, currently in development and scheduled to be available later this year at the Propane Training Academy.