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Compared to most types of commercial buildings, data centers are
energy hogs. A large data center, for example, can easily consume
as much electrical power as a small city. Of all the facility’s
HVAC equipment, the chiller is easily the largest energy consumer.
As such, significant HVAC energy savings can be realized by reducing
chiller energy. The fact that the most energy efficient chiller
should be selected for the facility goes without saying. However,
an even more important issue is that reducing the number of hours
of chiller operation can have a larger impact on the reduction
of that piece of the building energy pie than simply selecting
a more energy efficient chiller.
An airside economizer takes advantage of the hours of the year
during which the outdoor enthalpy (energy content) is less than
the return air enthalpy. Under such outdoor conditions, using outdoor
air reduces the load that would be experienced at the air handling
unit when compared to using the return air flow.
When the outdoor enthalpy is less than the return air enthalpy
AND higher than the supply air enthalpy, some mechanical cooling
is still required in order to meet the requirements at the supply
air set point. Under these circumstances, the chiller will be required
to operate, though not at as high a load as would be required for
a 100% return air system. Significant energy savings can
be realized whether a partial or full economizer is utilized.
However, are humidity and protection of the equipment put at risk? What
about regional factors? Ultimately, reliability is still
the name of the game.
Syska’s Critical Facilities Team takes a look at airside economizers
and the possibility of utilizing this method of energy reduction
in a data center setting.
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