ASHRAE Journal - June 2022 - 58

ASHRAE TECHNOLOGY AWARD CASE STUDIES
Indoor Air Quality and Thermal Comfort
IAQ design was based on ASHRAE Standards 62.1-2016
and 55-2010 to meet indoor quality and thermal comfort
criteria. The objective was to provide occupants with a
comfortable and optimal indoor environment.
The DOAS provides the optimal amount of OA to each
space and minimizes the consumed energy. Air effectiveness
was considered based on the local VRF fan coil
units used to provide comfort cooling to the classrooms.
Common areas, classrooms, conference rooms and
other high-density spaces have CO2 sensors within the
breathing zone, which allow ventilation to be modulated
according to actual need. The third-level lab requires
four air changes per hour (ach) of exhaust air. All labs
maintain a negative pressure relative to the corridor to
prevent the migration of contaminants.
The IAQ design also looked at contaminant levels in
each classroom based on using electronic air fi ltration
provided at all VRF fan coil units to demonstrate that
OA levels could be dropped below those recommended
by ASHRAE Standard 62.1-2016. The design met the
ASHRAE Standard 62.1-2016 OA requirement based on
the Ventilation Rate Procedure.
The design verifi ed that the project complied with the
requirements of ASHRAE Standard 55-2010 and LEED
requirements for thermal comfort.
Innovation
To achieve net zero energy, a solar array is designed to
produce all the energy consumed on site.
The building is fully submetered, allowing real-time
access to data for HVAC, lighting and plug loads.
A revised control strategy for the DOAS operation and
locating the VRF air-cooled condensing units indoors
allowed for additional energy savings by not having
to oversize the equipment to accommodate the cold
weather climate. Since most of the cooling and heating
season is limited on part-load conditions, we observed
that the local VRF fan coil use was limited to peak shaving
of cooling and heating loads, and the main cooling in
the space was done by the DOAS units.
An automatic control-task tuning lighting system
interlocked with the building automation system (BAS)
allowed the ability to adjust light levels per space, set
time schedules and defi ne limits on maximum light
output. High-end trim and task tuning setting throughout
the spaces, the corridor and staircase lighting was
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reduced, and full lighting shutdown during non-operational
hours and fully automated lighting system with
a computer interface improved the effi ciency. During
the certifi cation period, the automated lighting control
system energy savings was recorded at 54.5% compared
to the IECC 2015 baseline calculation. The building is
equipped with a central lighting system with daylight
sensors throughout all spaces. Lighting for the project
showed a 68% energy reduction over baseline.
Operation and Maintenance
During design, the team advocated for involvement of
the operation and maintenance personnel to discuss the
proposed principles and obtain feedback. Mechanical
rooms and air-handling units are set up to provide the
required access and space for maintenance. Labs have
no ceilings, and most fan coils are installed either in
hallway cabinets or local mechanical rooms to facilitate
access. A BAS is implemented to automatically control
the various building systems and provide operation and
maintenance alarms. The building went through a commissioning
process to improve the operation of the systems.
After start-up, the school operating engineers, the
design engineers and the commissioning agent reviewed
monthly reports over a one-year span with comments
and actions that helped optimize the operation.
Cost Effectiveness
Total construction cost for the project was $23 million.
The mechanical system cost including controls was
$1.975 million and the PV arrays cost $994,000. A total
$1 million grant was awarded to the school from ICECF
in obtaining and documenting proof of obtaining net
zero use over a consecutive 12-month period. Since the
building was able to achieve Net Zero Energy certifi cation,
the grant money completely paid for the installation
of the PV arrays. Also, all future energy generated
by the PV arrays will completely offset the total energy
consumption cost during that year.
The difference in cost between the baseline mechanical
system (based on Standard 90.1-2007) and the system
provided for this project was approximately $300,000.
Based on the energy model, the energy savings alone
between the baseline system and the system provided
yielded a simple payback of 7.8 years. However, since
the building has demonstrated net zero energy performance,
the simple payback is close to zero years.
2022
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ASHRAE Journal - June 2022

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