ASHRAE Journal - September 2023 - 58

SECOND PLACE 2023 ASHRAE TECHNOLOGY AWARDS
consumed was electricity, and the remaining 12% was
natural gas. The total energy consumption for the year
of 2020 was 40,133,068 kBtu and the resulting emissions
were 437 MT of CO2e. While energy efficient upgrades
contribute a portion of the 75% energy reduction and
~90% emissions reduction, the change in use from
laboratory research to office is certainly the largest
driver. Gas use, however, was reduced significantly
due to the operating strategy of using the heat recovery
chiller and the air source heat pumps as first stages
of heat in the central plant. The overall low campus
FIGURE 1 Airside heat recovery schematics.
Typical Office AHU & Heat Recovery AHU
Min OA
Max OA
Cooling
Coil
EA
Filter
To Terminal
Units
occupancy and use during the post-renovation data
period should also be considered.
Indoor Air Quality
Features that enhance the employee experience
and improve employee productivity are paramount
to attracting and retaining talent. Indoor air quality
was enhanced through strategies including increased
volumes, filtration and monitoring. Air-handling
unit (AHU) design volumes exceed ASHRAE Standard
62.1-2010 by 50% to ensure adequate system level
ventilation and to minimize indoor CO2 levels. Space
CO2 sensing influences outdoor air delivery but also
reduces outdoor air during reduced occupancy to
minimize energy consumption. All air-handling units
providing ventilation include MERV 13 filtration with
space provisions for future carbon filtration if needed.
Design modeling of different occupancy patterns drove
a better understanding of how CO2 levels might change
based on ventilation quantity. Interior plantings were
selected for their oxygen content, supporting high
cognitive function. Additionally, the existing building's
expansive 16 ft (4.9 m) floor-to-floor heights provide
58
ASHRAE JOURNAL ashrae.org S E PTEM B ER 2023
MERV 13
Filter
Future
Carbon
Filter
Heating
Coil
Cooling
Coil
OA
EA
CASE STUDY
impressive views of Elliott Bay, creating open, airy and
flexible workspaces.
Innovation
Three innovative elements of the campus HVAC
approach include:
Central Plant Reuse. Careful study early in design
led to thoughtful reuse of many central plant elements.
The previous plant had substantially more capacity
than required for this campus, allowing reuse of chilled
water and condenser water mains as well as most of the
existing chilled water
distribution to campus
buildings. Existing
chillers were retained
and refurbished.
This selective reuse
approach not only
reduced cost and
construction duration,
but also drove down
embodied carbon.
Increased
MERV 8
Filter
Cooling
Coil
L4
L3
L2
L1
Ventilation. The
increased ventilation rates in the Basis of Design drove
an innovative approach to space level CO2 control and
conference room ventilation design and drove the
inclusion of relief air AHU heat recovery as another
option for energy savings.
Campus Heat Recovery. By focusing a centralized
heat recovery chiller for primary heat recovery, we
were able to pick up 24/7 cooling loads from each and
every building and maximize our recovered heat to be
used across campus.
Final Thoughts
This campus development project incorporated
design and construction resources and undertook a
series of studies to help the owner make important
decisions. By thoughtful analysis, we were able to add
value and make huge decisions, like demolishing the
entire steam system and moving toward more energy
efficient, lower temperature methods. Studies also
showed we could achieve superior energy performance
by using an overhead VAV system, saving a large
amount of first cost.
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IDF/Electric Low Pressure System
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ASHRAE Journal - September 2023

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