ASHRAE Journal - July 2014 - 38

2014 ASHRAE TEcHnology AwARd cASE STudiES

Figure 1: Virtual model of variable primary chilled water pump battery and dual
compressor water cooled chillers.

Photo 1: As-built perspective of variable primary chilled water pump battery and
dual compressor water cooled chillers.

as-built comparison of the variable primary chilled
water pumps and water cooled chillers.
Integrated building design methodology was used to
optimize holistic facility energy efficiency, to right-size
facility services, to allow early equipment selection and
release, to accommodate a fast track schedule, and to
provide early phased occupancy.
The geothermal loop is based on a decoupled
approach. The building loop incorporates variable
speed/volume pumping to respond to "Off-Line" and
"Operating in Dead Band" units. The well field loop
incorporates variable speed/volume pumping to
respond to heat rejection/extraction requirements of
the building loop. The well field contains 45 wells partitioned into three subzones, each containing 15 wells for
reliability.
HVAC chilled water plant design is based on variable
primary flow configuration employing a 14°F (7.7°C)
temperature differential. Variable primary chilled
water and constant volume condenser water pumps are
decoupled from individual chillers so that rotational
reliability can be provided. Condenser water pumps
use VFDs and flow measurement to match individual
and staged pump operation to variable system curve
characteristics.
All chilled water piping outside of the mechanical
equipment room is configured with grooved piping and
zoned so that scalable additions/modifications can be
incorporated to compliment changing manufacturing
requirements. Based on the virtual model, pipe sections
were pre-grooved in the shop and delivered to the site
for ready installation.

Machining, assembly, and paint zones use decoupled
ventilation and sensible cooling architecture. The ventilation units incorporate total energy recovery wheels
to pretreat 100% outdoor air with available excess building air. Ventilation air is injected via high-throw drum
louvers in central locations. The air turnover units,
designed to serve process sensible cooling needs only,
continuously turn cooling air and ventilation air over
so that ventilation air is mixed throughout the plant
breathing zone. Air turnover units incorporate variable frequency drives to respond to varying shift process loads and to selectively improve dehumidification
response.
HVAC system infrastructure was designed and
installed to allow staged occupancy. The main office and
employee services areas were configured with GSHP
and DX DOAS equipment so as to allow CAT to move in
about six months prior to completion of plant construction. Plant rooftop equipment was designed to provide
construction and pre-occupancy phase conditioned ventilation and flush-out without risking contamination of
recirculation paths.
Machining and assembly areas incorporate translucent
lighting roof panels and high-bay exterior fenestration
to provide daylighting enhancement on the production
floor.
HVAC and process systems layout allows for scalable addition of reliability and growth infrastructure,
notably:
* The HVAC chilled water plant includes provisions
for addition of a future 500 ton (1,760 kW) chiller, chilled
water pump, and condenser water pump. Capacity addi-

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ASHRAE Journal - July 2014

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