Retrofits: Sustainable Strategies

  February 25, 2011

I'm Dan Hounsell, editor of Maintenance Solutions magazine. Today's topic is, sustainable retrofit solutions.

For maintenance and engineering managers with the Des Moines (Iowa) Public Schools, students, energy efficiency, and utility cost savings are top of mind before, during, and after every building renovation and system upgrade they undertake. And the school district is not short on projects.

Of the 52 schools in the district, 38 have undergone renovations and upgrades that led to an Energy Star rating by earning a score of at least 75 on a scale of 100. The rating means those 38 schools perform better in terms of energy efficiency than 75 percent of similar buildings nationwide.

Due to the various projects the district undertakes, it is important for facilities technicians to have a resource they can use to keep track of the different green technologies and strategies. The district maintains a four-page document highlighting sustainable strategies in all aspects of facilities, including HVAC, recycling, lighting, transportation, water and land conservation, and purchasing. HVAC upgrades are responsible for many of the improvements in energy efficiency and the indoor environment. As part of its green and sustainable strategies document, the district lists the following elements specific to HVAC systems:

• variable-frequency drives on ground-source loop pumps and cooling-tower fan motors

• premium-efficiency motors

• carbon-dioxide sensors in HVAC systems serving large areas

• geothermal heating and cooling systems.

"We want to use the most current and latest technology as best we can, but we never like to be guinea pigs," says Dave Silver, the district's facilities director. "We like to use proven technology and proven products with a track record whenever we can. You're also thinking about energy usage and indoor air quality. One thing we're paying close attention to is the impact of mechanical HVAC equipment on the acoustics in the classroom."

Silver says the district completed five HVAC upgrades this summer, and geothermal installations were part of each project. The systems have been achieving the energy savings and indoor environmental quality goals the district expected, and the maintenance requirements have been minimal.


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