ASHRAE Journal - November 2020 - 45

2020 ASHRAE TECHNOLOGY AWARD CASE STUDIES

PHOTO 2 ELIF central mechanical room (steam to glycol heat exchanger).

©KENGRAHAMPHOTOGRAPHY.COM

of steam energy from the campus's central coal-ﬁred
power plant, conserving campus utility cost.
The facility's ventilation system was designed using
detailed pressure mapping in accordance with the
ASHRAE Laboratory Design Guide from project concept.
Pressure relationships, partition wall locations, door
swings, and door jamb sealing methods were thoroughly
understood and included for consideration as part of
facility programming. Differential pressures are maintained throughout the building using four 0.05 in. w.c.
(12 Pa) incremental differential pressure zones. This
level of "up-front" design detail allows the building to
provide simple, effortless zone pressure control between
its many zones.
All exhaust air from toilet rooms and other general
exhaust locations is ducted to the 100% outside air laboratory AHU system using exhaust air valves similar to
a typical laboratory suite. This allows all toilet/general
exhaust waste heat to be recaptured through the laboratory AHU air-to-air heat exchanger, contributing to outside air preheating. No small general exhaust fans with
direct exhaust were used on the project.
The two general recirculating AHUs, which support
office and general classroom areas, are tuned such
that their outside air intake rates match the supply
air deficient rate of the neighboring laboratory AHU
system, as well as meet IAQ requirements. Through
dedicated building pressure mapping, overall building pressure control is maintained with no direct
building relief air requirement during the heating
season. This provides nearly 100% ventilation system
heat recovery except for natural building exfiltration due to slightly positive building pressurization
control.

Operation and Maintenance
The building's HVAC system is designed to serve a
high-performance building in one of the harshest climates on the planet. Redundant backup systems are
fundamental, and system service accessibility is essential. The ﬁfth-ﬂoor dedicated mechanical penthouse
with elevator access allows for convenient HVAC system
inspection, maintenance, and, if necessary, equipment
replacement. Direct roof access from the penthouse provides for convenient rooftop chiller maintenance.
All air-handler systems share a common design
arrangement, except for capacities, for ease of understanding and operation. The three 100% outside air
AHUs further incorporate similar large air-to-air heat
exchangers with bypass control.
Outside air intake plenums are factory built by the AHU
manufacturer using the same insulated double-wall construction as the air-handler cabinets. Each intake plenum
unit includes a two-position, parallel-blade, insulated
damper with full thermal breaks for an ultratight thermal

1,600,000
1,400,000
1,200,000
1,000,000
800,000
600,000
400,000
200,000
0

Feb

Mar

Apr

May

First Stage

Jun
2018
Second Stage

Jul

Aug
Third Stage

Sep

Oct

Nov

Dec

Jan
| 2019

100
80
60
40
20
0
−20
−40
−60

Outside Air Temperature (°F)

Heat Output (Btu/h)

FIGURE 2 ELIF air-handling unit preheat coil waste heat utilization.

Outside Air Temperature

N OVEM BER 2020

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ASHRAE Journal - November 2020

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