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The Greening of IT
178 How Companies Can Make a Difference for the Environment

management features), server energy use will vary widely during the day. Just
using the server name-plate power will become more and more inaccurate.
Manufacturers have provided additional software to record equipment power
and temperature. We have installed data center energy management software
for a set of the servers as part of determining the best practices from the proj-
ect for all data centers we manage, including the one in this analysis.
As legacy equipment that will not be refreshed for several years does not
have this capability, we will have to use a combination of planned and actual
measurements for the next several years. To increase the accuracy of under-
standing energy usage of legacy servers, we are installing metering at differ-
ent levels of the power distribution. This will enable us to reconcile the
difference between the newer equipment we have data on and the older
equipment that we don’t have data on.

Step 5. Cool
Cooling improvements to the data center were provided by implementing
the recommendations of the energy assessment. Many of these suggestions
were tactical in nature and did not have a significant amount of investment ptg
required for the return. Other suggestions were more long term in nature.
The team provided information on the estimated amount of savings, the
implementation cost, and the return on investment period. In total, the team
identified improvement opportunities that would result in saving 10 percent
of the power in the data center.
Most people in IT are familiar with the cooling implementations where
data centers are air-cooled using Computer Room Air Conditioners
(CRACs). What they might not be familiar with is that simple air leaks
resulting in inappropriate air flow can dramatically reduce the efficiency of
this type of cooling solution. The two most common air leaks are in the floor-
based cable cutouts and in the spacing between servers that are installed in
racks. To mitigate the cutout leaks, brushes were installed in the cutouts.
Rack-spacing leaks were mitigated by installing panel blanks in the racks.
Most IT equipment is designed to be cooled by having cold air come in the
front of the equipment and leave heated through the back. Without panel
blanks installed, hot air recirculation was misdirected.
The next area of tactical cooling improvement was the actual placement of
perforated tiles. These tiles are designed to go into the cold aisles so that cold
air can enter the front of the IT equipment. Over time, aisles were moved and
equipment reinstalled so that the perforated tiles were not in the optimal