For those who don’t live there, Maine has a reputation as being a cold place in the winter. Actually, those who live there think that, too. Snow? Average about 70 inches. Temperature? The average for January is 7 degrees. Needless to say, buildings are weather proofed as much as possible, and heated as economically as possible. Mainers have another reputation to uphold: they are thrifty and conserve energy.
Maine became a state in 1820 and, like Maine itself, the Maine National Guard has the distinction of having existed as an organization prior to the existence of the United States itself. The National Guard is composed of various units, including aviation, based at facilities throughout the state.
In Bangor, a city of 32,000, the Guard’s Aviation Support Facility has taken to technology for a defense against winter. Not content with building envelope improvements and a solar photovoltaic installation at the aviation facility, they have pioneered the use of micro-combined heat and power (micro-CHP) systems to cut energy costs and carbon emissions while improving resilience and redundancy.
Combined heat and power systems save energy and reduce carbon emissions by reusing the heat that is produced when generating electricity. The energy manager, A. J. Ballard, worked with Dalkia Aegis, a manufacturer, developer, and installer of propane and natural gas micro-CHP systems, to design CHP systems for two of his facilities.
The first, a 75-kW micro-CHP system, at the Aviation Support Facility, demonstrated how much energy savings micro-CHP can achieve. The results so far? It’s cut 30% of the facility’s energy consumption, creating about $60,000 of savings per year. The project, which won an Energy Star CHP award, served as a model for future CHP projects with the Army National Guard and specifically for the new NMRC (Northern Maine Readiness Center), a 45,000-sq.ft. facility in Presque Isle, Maine, serving the Army National Guard 185th Engineer Support Co.
Obviously, the Army National Guard has locations all over the country, and not all facilities have access to natural gas. Maine’s Aviation Support Facility and NMRC, for example, could not access natural gas to power the CHP system, so Dalkia Aegis designed the systems to run on propane. The NMRC uses two 10-kW micro-CHP units from Yanmar as the primary heat sources for the low-temperature radiant slabs used in the building, as well as for domestic hot water. The micro-CHP units are tied together with propane boilers for backup heat, with the boilers kicking in automatically when additional heat is needed or if the CHP systems go down.
The micro-CHP system also meets a new directive from the Army to provide resilience and redundancy in its facilities by providing a backup power source. If the NMRC is affected by one of Northern Maine’s numerous outages, caused by an aging grid or severe weather, the CHP units continue generating power to keep the facility’s administrative offices functioning.
While energy savings have historically been the primary driver for facilities looking at CHP systems, resilience, and carbon footprint reduction have become more important in recent years. A common misconception is that because micro-CHP systems run on propane or natural gas, they are creating additional carbon emissions. In reality, because micro-CHP systems are so efficient, they can heat and power a facility with fewer carbon emissions than relying on today’s power grid.
Architects and engineers might also be surprised by the small footprint and quiet operation of today’s micro-CHP systems. A typical unit fits in a 4-by-8-ft. footprint about as large as a sheet of plywood, and with noise levels around 70 decibels, they can be the quietest piece of equipment in the boiler room. That makes them a great option for facilities where lots of people are using heat and hot water, such as multifamily buildings; healthcare and nursing homes; hospitality and athletic centers; prisons; and, of course, Army bases and barracks.
In the near future, facilities may also be able to bring cleaner fuels into the mix such as hydrogen, which can be mixed with propane or natural gas, and renewable propane or natural gas.
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