ASHRAE Journal - December 2020 - 48

Campus Science Building was modeled and predicted
to use 83.2 kBtu/ft2·yr (262.5 kWh/m2), and is currently
operating at an EUI of 79.63 kBtu/ft2·yr (251.2 kWh/m2),
which is one of the most energy-efﬁcient community
college buildings in the academic system.
Since laboratory buildings use simultaneous heating
and cooling, a modular heat-recovery chiller was used
in place of the traditional chiller and boiler cooling
and heating plants. This system has the ability, when
producing 45°F (7.2°C) chilled water, to simultaneously
produce 120°F (48.9°C) water by capturing the heat
rather than rejecting it. The HVAC design used two airhandling units to handle the heating and the cooling of
the building and the required ventilation air. The laboratory spaces required one-pass-through air due to the
high amount of exhaust with the fume hood, and, thus,
a 100% outdoor air system was provided with a runaround heat recovery coil in the exhaust airstream.
The classroom and ofﬁce spaces do not have this same
requirement; therefore, a traditional VAV air-handling
unit with heating and cooling coils was used to heat and
cool these spaces. However, this unit did not provide the
ventilation air to these spaces. The ventilation air was
provided through the laboratory unit. The advantage of
providing ventilation air via the 100% outside air lab unit
to non-lab spaces in lieu of the traditional air-handler
VAV system was the ability to use demand control ventilation via occupancy sensors and the energy recovery of
the run-around loop.
To generate additional energy reduction, dual-contact
occupancy sensors were provided to control the lights
in the building and to reset the temperature set point
during occupied times. In addition, the occupancy sensors were also able to be used to shut off ventilation
air in the classroom and lab spaces during occupied
hours because sensors were monitoring occupancy at
all times. Venturi valves were used in all lab spaces that
were designed to precisely control air at 8 ach, but also
allowed for a demand response to occupancy and hood
use.
When labs were unoccupied, or during unoccupied
hours, airﬂow reduced in labs from 8 ach to 2 ach, allowing for a reduction of 27,000 cfm (45 873.29 m3/h) of
conditioned 100% outside air. The design team additionally carefully coordinated the user group's hood sash
height requirements, where a reduced sash height from
18 in. (457 mm) in height to 12 in. (305 mm) was deemed
48

ASHRAE JOURNAL

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D ECEM BER 2020

FIGURE 1 Modeled EUI vs actual EUI.

EUI (kBtu/ft2·yr

2020

ASHRAE TECHNOLOGY AWARD CASE STUDIES

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Modeled EUI

Jun

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Dec

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Actual EUI

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appropriate for student use. The sash height reduction
allowed for an exhaust air reduction while operating
hoods of 7525 cfm (12,785 m3/h), compared to a working
sash height of 18 in. (457 mm) and a lab air-handler coilsize reduction of approximately 21 tons (74 kW).

Indoor Air Quality and Thermal Comfort

ASHRAE Standard 62.1-2010 air quality calculations
were performed for the science building. The building has a 100% outside air-handling unit that delivers
ventilation air to the entirety of the building. The air
handler uses a UV light system to treat for entering
airborne pathogens and microorganisms. Ventilation
air is designed to be closely monitored, measured, and
delivered with a combination of VAV boxes and venturi
valves that display cfm airﬂow values to a controls system graphical front end. To maintain safe and comfortable lab working spaces for students and staff, all lab
spaces in the building were designed to exceed ASHRAE
Standard 62.1-2010.
Venturi valves were implemented in the design to
accurately monitor airﬂows and pressurizations, and to
provide an immediate response to the lab hood operation in all labs on two ﬂoors of the building. Safety of
lab spaces is paramount and, as such, outside air and
exhaust air is provided 24/7 to lab spaces where users
have implemented occupancy schedules.
The system achieves 8 ach in occupied lab spaces, and
responds to an unoccupied schedule where lab spaces
are maintained at 2 ach or an airﬂow rate to maintain
minimum hood velocities. Venturi valves allow the system to remain active, so if a hood is operated during any
occupancy schedule, it will be successfully and safely
maintained at a minimum sash velocity. Administration
spaces and classrooms are provided with ventilation air

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ASHRAE Journal - December 2020

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