Should You Implement an Air-Side
Economizer for Your Data Center?
IN THE RIGHT CONDITIONS, YOU CAN SAVE ON DATA CENTER COOLING
The need for efficient data center cooling is growing quickly, as its global market
is expected to reach $20 billion by 2024,
according to a study from Market Study
Report. Facilities managers need every
advantage to reduce energy spend from
data centers, and for many facilities, using
air-side economizers is the best choice to
reduce costs for cooling.
Air-side economizers cool data centers
by bringing outside air into a building and
distributing it to servers. They are integrated into a central air handling system
with ducts for intake and exhaust, and their
filters reduce contaminants from entering
the data center. When properly integrated,
economizers can reach up to 30% energy
savings on cooling, although in many
cases they don’t reach this potential due
to poor design and implementation, as the
American Council for an Energy-Efficient
Economy describes. These systems require
proper planning because of some of their
inherent limitations.
One significant problem with air-side
economizers is that they do not always lend
themselves to retrofits. Many data centers
are located in the interiors of lower levels
and basements in buildings, so an air-side
economizer might not be the most cost-effective solution because the data center is
hard to reach. If you can get it to effectively
reach your data center without too much
expense and difficulty, they can be especially effective.
CLIMATE CONCERNS WITH AIR-SIDE
ECONOMIZERS
But because the air is brought in and
out of the building without recirculation,
the outside air needs to be under the right
conditions. In cooler climates, they work
exceptionally well. According to Lawrence
Berkeley National Laboratory, if the outside
air is cool enough, only the fans need to be
run and the mechanical cooling equipment
can be shut down, contributing to energy
savings. Even when it isn’t cooler outside,
air-side economizers can operate.
“If the outside air temperature is higher
than the required supply air temperature
but lower than the temperature of the air
returning to the cooling equipment, it can
still provide partial cooling and reduce the
load on the cooling equipment," explains
Berkeley Lab. "The effectiveness of this
scheme depends on the local climate and
the ability to move a relatively large volume
of air simultaneously into and out of the
One simple way to reduce the heat of
the air used and get the most out an air-
side economizer is to make sure outside air
intakes are located on the north side of a
building because there is significantly less
solar heat gain compared to the south side,
explains the Department of Energy.
Even if your facilities are in a warmer climate, you still have options for savings with
an air-side economizer, says ENERGY STAR:
“Because data centers must be cooled 24/7,
365 days per year, air-side economizers may
even make sense in hot climates, where they
can take advantage of cooler evening or
winter air temperatures.”
The wrong combination of heat and
humidity can decrease the savings potential of an air-side economizer. For example,
cool air that is very dry might require you
to spend a considerable amount on humidifying the air, which cuts into the savings
your economizer would otherwise provide.
ASHRAE provides recommendations for
where air-side economizers work best. Be
sure to consult with engineers about how
one might work in your climate.
Unique HVAC Debuts
at Cornell Tech
NYC CAMPUS WELCOMES FIRST-OF-ITS-KIND TECHNOLOGY
For the first time in the United States, a supplemental groundwater pumping system will increase the efficiency of a
closed-loop geothermal system.
The Roosevelt Island campus of Cornell
Tech, Cornell University’s applied technology program, will obtain all of the heating,
cooling and domestic hot water for its
Emma and Georgina Bloomberg Center
from the ground source heat pump system without combusting any fossil fuels.
Together, the facility’s energy-efficient
design, solar PV panels and the innovative
heat pump will save roughly 500 tons of
carbon dioxide per year.
The Bloomberg Center’s geothermal
system relies on water-filled fissures in
the local bedrock. The water is tapped
by 80 boreholes, each 400 feet deep, as
part of the groundwater pumping system.
This process then increases the efficiency
of the closed-loop geothermal system,
ensuring lower energy use and a smaller
environmental impact.
“The Bloomberg Center’s innovative
ground source heat pump system is a
perfect match for Cornell’s mission of
education, research and outreach,” says
Steve Beyers, Energy Engineer at Cornell
University. “It demonstrates respect for the
environment while saving energy dollars
for investment into our education mission,
but it’s also a great experiment in new
I
WA
N
B
A
AN
CORNELL TECH will use a ground
source heat pump with a closed-loop
geothermal system to obtain heating,
cooling and hot water for its Roosevelt
Island campus.
