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

Data Center Stored Energy Including Stored Cooling

One of the new innovative cooling solutions available for the data center is
stored cooling. Technically, this works something like the old idea of having
an icehouse, where during the winter, ice chunks are cut from the frozen lake
and stored in an ice warehouse with the ice covered with straw. Then in the
summer, the ice is transported to your icebox (replaced by modern day refrig-
erators). In concept, data center stored cooling is a type of 21st-century tech-
nology to replace the 19th-century icehouse. Just like the icehouse, the
technology works best when used in a climate where it gets cold in the win-
ter, and you have lots of “cold” to store. Canada, for example, is a good choice
for the technology. Because I grew up in North Dakota, I can attest that this
state has a lot of winter cold to store for cooling of data centers.
In addition to stored cooling for data centers, innovations are underway for
many types of stored energy. One interesting initiative is the partnership
between the U.S. DOE Energy Storage Research Program and the New York
State Energy Research and Development Authority (NYSERDA) to demon-
strate electrical energy storage options. The demonstration projects include ptg
electrical energy storage devices at multiple sites in New York State. The
projects are described online at http://www.storagemonitoring.com/
nyserda-doe/storage-home.shtml.
In the solar power section, Appendix C, “Comparison of Different Power-
Generation Methods,” describes methods for storing energy. Some of these
energy storage methods could be applicable for data centers. The storage
methods include the following:

■ Thermal storage systems can generate electricity during cloudy weather
and at night.
■ Thermal mass systems can store solar energy in the form of heat at
domestically useful temperatures for daily or seasonal durations.
Thermal storage systems generally use readily available materials with
high specific heat capacities such as water, earth, and stone. Well-
designed systems can lower peak demand, shift time-of-use to off-peak
hours, and reduce overall heating and cooling requirements.
■ Phase change materials such as paraffin wax and Glauber’s salt are
another thermal storage media.