Energy savings improves
the bottom line
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high-resolution instruments, IBBR researchers have figured out the molecular structure
of proteins, unraveled the protein interactions involved in autoimmune disorders and
discovered possible countermeasures for
Their infinitesimally precise experiments
require around-the-clock lab access—and
those labs require a stable environment. A
change in room temperature of just one or
two degrees could twist the outcome of an
experiment; increased humidity could interfere with sensitive scientific equipment.
With all this in mind, the IBBR facilities management team—challenged by a
state mandate to reduce energy consumption and a university commitment to
reduce total energy consumption 20 percent by 2020—embarked on an aggressive
energy reduction plan. One of the first
actions: a chiller plant optimization project that achieved substantial savings.
When the project began, the plant was
consuming energy at 0.9 k W/ton and
operating at just 50 percent output. Now
the plant runs 27 to 37 percent more
efficiently, effectively keeping energy costs
flat while building occupancy increased.
IBBR has also reduced CO2 emissions by
about 125 tons per year and improved
plant reliability, so that the lab environment remains stable, even through icy,
snowy winters and hot, humid summers.
T WO BUILDINGS, ONE PLANT
The IBBR campuses, part of the University
System of Maryland, occupy over 200,000 sf
of lab and office space in Rockville. The original building opened in 1989, and a wing was
added in 1995, for a building total of 75,000
sf. Each wing has separate chilled water
plant and hot water systems and mechanical
systems, built to size for the original construction. The systems were connected when
the new wing was built, but the components
remain segregated. This allows the systems
to operate as though they are a single plant,
with built-in redundancy. Building 2, built
in 2007, is a 126,000 sf facility that also has a
chiller plant and a steam-heating plant.
Combined, the entire system—the IB-
BR’s environmental stabilization plant—
maintains the lab environment by condi-
tioning and controlling the temperature,
humidity, and quantity of air flowing to
and through the labs in each building
with large, 100 percent ventilation air
handling units and a combination of vari-
able and constant volume terminal units.
A Siemens Apogee building automation
system controls and monitors the plant.
Facilities staff knocked out easier
projects first. They took steps to conserve
water, which IBBR was using at a rate of
1 million gallons a month. They attacked
the lighting, which consumes 20 percent
of the lab’s energy, and reduced the number of fixtures installed throughout the
labs. Then the real work began. Because
the HVAC system accounts for as much
as 70 percent of the lab’s energy use, they
first turned their attention to optimizing
the 900-ton chiller plant in Building 2.
NEWER CHILLER PLANT COMPONENTS ARE
Although it was just five years old when
IBBR launched its project, Building 2
turned out to be the better candidate for
HVAC optimization. Its 900-ton plant
has two 450-ton electric centrifugal water
chillers, two condenser water pumps, two
cooling tower cells, two primary pumps
and two secondary pumps.
It was originally outfitted with several
variable speed pumps, but the primary
chilled water and condensing pump ran
at a constant volume, the cooler towers
were configured to maintain a consistent speed, and water temperature was
controlled with a cooling tower bypass
valve—these were prime targets for efficiency measures.
The chillers were manufactured at the
same time, but one of them had never
run as efficiently as the other and had ongoing problems with surging. The plant
has to provide 3,800 hours of cooling
every year, so the facilities staff started
their review of individual plant components with the chillers. They found that
optimizing each component separately
could significantly increase the plant’s
overall efficiency, allowing it to operate
at the lowest possible k W/ton without
degrading the atmosphere of the labs.
SOLUTION: A SYSTEM BUILT ON
IBBR chose Optimum Energy’s Op-
tiCx HVAC optimization platform with
OptimumLOOP control software for chilled
water systems. It offered several advantages:
it used much of the existing plant equip-
ment; a dedicated Optimum engineer would
oversee implementation and consult on best
practices; and the solution “self learns” the
most efficient operating conditions of each
component, then uses that intelligence to
optimize the entire plant.
From the variable-speed drives and sen-
sors installed on chillers, pumps, valves and
tower fans, the OptimumLOOP software
collects a tremendous amount of data about
the plant equipment, including water flow,
electrical power consumption, load con-
ditions and more. It compares the data to
control algorithms, assesses plant conditions
in real time and then automatically changes
pump and fan speeds, leaving chilled water
temperature, equipment staging and other
operational changes to maximize efficiency.
IBBR began deploying the solution in
2013, after completing the university’s
procurement process and getting some
funding from their local energy provider.
The first step was installing some new
variable drives to convert IBBR into an
all-variable-flow plant, as well as the
sensors on each plant component.
Next came connecting OptimumLOOP
with the Siemens building automation system and upgrading the building automation
system network in Building 2 to Ethernet
to ensure the data flow wouldn’t challenge
the local network capacity. When that was
finished, IBBR had OptimumLOOP up and
running across the chiller plant—just in
time for the cooling season of 2014.
ENERGY USE DROPS 30 PERCENT
In the first year of full operation, the
optimized plant cut the IBBR’s energy use
by an average of 30 percent. Originally, each
primary chilled water pump ran consistently
at 60 Hz. Now they each run at an average
of 55 Hz. By itself, that may not appear
to deliver huge savings, but the change in
speed provides about 20 percent savings for
these pumps alone. And OptimumLOOP’s
relational control algorithms maximize
overall plant performance and meet the
optimal parameters for current conditions.
IBBR found that running individual pieces
of equipment at more efficient speeds adds
up to one big number.
2014 was a year of testing and tuning.
For instance, in trying to protect itself
from surging, the chiller control panel
ended up hampering energy efficient
operation. The chief problem was old
data: working with Optimum engineers,
the IBBR facilities team urged chiller mechanics to update the data at the control
panel, and Siemens engineers adjusted
the chiller code in their system to address
condensing water control issues.