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As the discretionary operation of
diesel generators becomes
increasingly restricted and the
recently announced Clean Power
Plan enters the implementation
phase, a pivot toward
cogenerated cooling from
resilient dual-fuel gas turbines
will become essential to the
boomer data center industry.
And radial gas turbines rated at
1.8MW are ideally designed for
data center applications.
Coupled with an absorption
chiller, a single turbine generator
displaces 2300kW of electric
power from the grid. But more
importantly, a dual-fuel turbine is
capable of smoothly switching
from 100% natural gas to 100%
diesel at full load without power
interruption in the event that the
utility gas supply is disrupted.
Such turbines can single-
handedly provide superior
reliability of prime electric power
and equipment cooling during
normal operation and in times of
emergency, reducing or
eliminating requirements for
backup diesel generators, UPS,
and associated maintenance.
Data centers are large power
consumers and heat producers,
requiring backup generators and
redundant cooling to qualify for
high reliability ratings. Diesel
generators sufficient to power
the electronics and electric
cooling (normally powered from
the grid) have been the standard
for data center standby power
due to their ability to startup
rapidly in the event of a power
outage. Uninterruptible Power
Supplies (UPS) bridge the gap to
maintain power during the ten
seconds it takes for the diesels
come on line. Despite tightening
restrictions on exercising diesel
engines for maintenance and
reliability checks, gas
reciprocating engines have not
displaced diesels. Gas engines
are slower to start and bring up
to full load, so they must be
accompanied by higher-capacity
UPS. Further, the probability of
gas supply disruption during a
major disaster results in
unacceptable system reliability
for the gas option. While some
gas generators can be operated
on diesel as well, they typically
required a minimum diesel flow
at all times, making extended
operation unacceptable unless
expensive emissions controls are
employed.
Enter the dual-fuel gas turbine,
capable of smoothly switching
from 100% natural gas to 100%
diesel at full load without power
interruption in the event that the
utility gas supply is disrupted.
The generator is operated 24/7
on 100% natural gas in parallel
with the grid, transitioning
seamlessly to island mode when
grid power is interrupted. In
order to maximize value during
normal operation, an absorption
chiller powered by turbine
exhaust provides continuous
equipment cooling to the facility.
Excess chiller capacity is
employed in a turbine inlet
cooling (TIC) system to boost
generator output.
by brent voelker
Fueling the inFormation economy:
ResilienT PoweR anD
CogeneRaTeD Cooling
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7X24 MAGAZINE FALL 2015