Feature
Story
Cool Trends on Campus:
A survey of thermal
storage use
energy
John S. Andrepont, President, The Cool Solutions Company
The use of thermal energy storage by
district cooling systems on college, university and other campuses has been
documented throughout the past two
decades, particularly in recent years.
Many of these thermal energy storage
(TES) examples have been presented as
case studies at International District
Energy Association conferences or in
District Energy magazine articles.
While such case studies have helped
illustrate that TES offers a wide range of
potential benefits (see sidebar), it has
remained unclear exactly how widespread
the use of TES on campus
has become. The author
recognized that a survey
of campus TES systems
would provide meaning-
ful and useful insights
into the extent and form
of campus TES applica-
tions. This ‘benchmark-
ing’ of campus TES use
could be beneficial, both
to existing campus own-
ers/operators of TES
systems and to those con-
sidering – or even those
who may not yet have
considered – employing
TES on their campuses
around the world.
To that end, Cool
Solutions conducted a
survey during 2004 to
document and quantify
campus TES use, supplementing and formalizing
data it had been accumulating on the issue for a
number of years. Though
data can often be dry
and uninteresting, the
results of this survey are decidedly ‘cool’
and should be beneficial for campus utility planners and operators, not to mention business officers and trustees.
The sheer number of campus TES
installations, the cumulative impact on
electric load management, the broad
range of geographic locales and climatic
conditions, and notably the large number
of repeat users (either multiple TES phases
at a single campus, or TES at multiple
campuses within a campus system) are
all quite eye-opening – even to those
Chicago Bridge & Iron Co.
Installed in 1996 at the University of California–Irvine, this 46,150-ton-
hour chilled-water TES tank is the largest of eight similar installations at
seven UC campuses around the state. Total stratified chilled-water TES
capacity on UC campuses is 254,000 ton-hours, representing a peak
electric load shift of approximately 27 MW, or 3. 4 MW per installation.
Large TES installations added in lieu of conventional chiller-plant capacity at times of system expansion often provide significant capital cost
and operating cost savings.
To date, 159 identified TES
installations, on 124 campuses,
comprise more than 1. 8
million ton-hours of daily
TES capacity and achieve an
estimated total peak load shift
of more than 258,000 tons (or
194 MW).
already familiar with the TES marketplace.
To date, 159 identified TES installations,
on 124 campuses, comprise more than
1. 8 million ton-hours of daily TES capacity and achieve an estimated total peak
load shift of more than 258,000 tons (or
194 MW). On average, they exhibit a TES
capacity of 11,374 ton-hours and a peak
load shift of 1,625 tons (or 1. 2 MW) per
