Snowmelt system controls adjusted to save energy

At this large office campus, the sidewalk snowmelt system had never been reviewed or commissioned.


During a recent retro-commissioning investigation for a large office complex, exp U.S. Services learned that the boiler-heated glycol system used for snow melting ran continually whenever the outdoor air temperature was below 38 F. NOAA weather records revealed that while the temperature is below 38 F for about 2250 hours/year, the actual amount of time of snowfall is only 580 hours/year. This difference of about 1700 hours represents the time the snowmelt system is on when it doesn’t need to be.

Because large areas were covered by eight different snowmelt systems, the calculated annual savings was 43,000 therms of natural gas and $21,000. This system was installed many years before the popularity of commissioning, but this speaks to the need for retro-commissioning, and/or at least a periodic review of control sequences and operations. 

Terrence Malloy is project manager for the energy solutions group at exp US Services Inc. He focuses on energy conservation, retro-commissioning, and renewable energy systems.

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