ASHRAE Journal - March 2021 - 20

2021

ASHRAE AWARD OF ENGINEERING EXCELLENCE

By controlling where the excess ventilation air is introduced into the building, the team was able to increase
ventilation rates throughout the building and thus
increase the indoor air quality not only in the labs, but
also in the adjacent ofﬁce spaces. Because the laboratories require continuous exhaust even during unoccupied hours, the cascading air system results in a thorough ﬂush out of the ofﬁce spaces every night.
The added beneﬁt of the cascading air strategy is the
reduced amount of reheat energy needed to condition the lab spaces. Because of the high air change rates
required in laboratories, many of the spaces would
become overcooled if not for a signiﬁcant amount of
reheat energy. The air being transferred into the labs
from the adjacent ofﬁce spaces reduces the reheat
demand by using internal heat loads of the ofﬁce space
to warm up the air prior to being transferred into the
labs. It is estimated that fan energy and reheat reductions total 25 kBtu/ft2·yr (284 MJ/m2).
The project used ASHRAE Standard 55-2010 criteria to
meet thermal comfort targets. The Center for the Built
Environment Thermal Comfort Tool was used with the
following summer and winter conditions to verify compliance with ASHRAE Standard 55-2010:
* Activity level: 1.4 met;
* Space temperature: 72°F (22°C);
* Clothing thermal resistance values (clo) assumed:
1 (winter)/0.5 (summer);
* Radiant thermal control: N/A;
* Air velocity: 20 fpm (0.1 m/s); and
* Humidity/condensation: 50% relative humidity.
A post-occupancy survey recently conducted shows
that 90% of building occupants who responded to the
survey are " somewhat satisﬁed, " " satisﬁed " or " very
satisﬁed " with the air quality in the building and only
3% are " somewhat dissatisﬁed, " " dissatisﬁed, " or " very
dissatisﬁed. "

Innovation
Safety is a primary goal within any laboratory environment. Fume hoods, chemical storage cabinets and high
air change rates are used to maintain a safe indoor environment. To ensure a safe outdoor environment around
the building, lab exhaust discharge locations and velocities were studied using wind tunnel testing. Based on
actual locations of lab exhaust fans, outdoor air intakes
and occupied outdoor areas, the wind study informed
20

ASHRAE JOURNAL

ashrae.org

MARCH 2021

FIGURE 3 Cascading air strategy.

Exhaust Air Supply Air
Valve
Valve
Exhaust
Air
Valve Supply
Diffuser
Fume
Hood

Lab

VAV
Terminal
Unit
Transfer
Fan

Supply
Diffuser

Return
Grille

Ofﬁce

the design team of the minimum discharge velocities
required at speciﬁc wind speeds and directions. In general, the calmer the wind, the lower the discharge velocity needed to ensure the exhaust plume extends a safe
distance from the building (Figure 4).
An anemometer was installed on the roof of an adjacent building, which is taller than the Knight Cancer
Research Building. The anemometer communicates
with the HVAC controls system and provides real-time
wind speed and direction, which is used to reset the
minimum speed of the lab exhaust fans.
Fan speed has a cubed relationship to energy, which
means signiﬁcant potential to reduce energy use exists if
fans are allowed to operate at slower speeds. Being able
to turn down the lab exhaust fans during calm conditions is estimated to reduce the overall energy use of the
building by 10 kBtu/ft2·yr (114 MJ/m2·yr) without compromising the safety of the occupants in or around the
building.

Maintenance + Operation
Having the owner and building engineer involved
during the design phase kept the team focused on
how the building was going to be operated and maintained. The owner, Oregon Health & Science University
(OHSU), owns and maintains many buildings on their
campus, and as a result they have very vibrant design
and construction and building operation groups that
provided input into the project throughout the design.
Control sequences that have been tested and proven
on previous projects were implemented, and locations
of service valves, ﬁlters and disconnects were scrutinized. Thorough commissioning of mechanical, electrical, plumbing (MEP) systems was performed prior to
occupancy.
One important component of operating and maintaining a high efﬁciency building is a robust controls

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ASHRAE Journal - March 2021

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