With HVAC Upgrades, Look Beyond Like-Kind Replacement
February 9, 2012
Today's tip from
Building Operating Management magazine: When replacing elements of the HVAC system, evaluate whether to replace units with a like kind or not.
Say you're replacing a chiller. Because chillers can easily last 30 years or more, the odds are good that the needs of the building and its occupants have changed since it was installed. In that case, it probably isn't a good idea to replace units with like kind.
For one thing, chillers with older technology are not as energy efficient as units made today. What's more, you might find out that the size of the existing unit may not meet the needs of current and future occupants. There's also the question of how much redundancy you have and need. Questions like those are why bringing in an outside engineer, while an added expense, is probably a good idea.
The result of not replacing in kind can be significant. Two Shell Plaza in Houston was formerly outfitted with four 500-ton chillers. As a result of an upgrade by Hines, two of those chillers remain, but only in a backup role. The cooling is now provided by a pair of 680-ton chillers with variable frequency drives. That approach not only allows for more efficiency, but also gives more flexibility when it comes to providing cool air during off-peak hours when only a limited number of tenants need it. Changes like that can only come about if a project is properly evaluated beforehand and the building's use is carefully examined.
In some cases it might be preferable to replace with similar units. Kirk Beaudoin, territory facilities manager, North American retail operations, Nike, says that tracking service calls, breakdowns and temperature complaints helps his company identify problems that would prevent the organization from being able to replace old units with similar new units. "Our assumption is that our stores were properly designed when built. So unless we have identified ongoing comfort issues that are related to sizing of equipment, or if there have been any modifications to the store which would require a review of the systems, we generally replace with the same tonnage," he says.
This has been a
Building Operating Management Tip of the Day. Thanks for listening.
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