ASHRAE Journal - May 2024 - 58

2024 ASHRAE TECHNOLOGY AWARDS CASE STUDY
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space via the clerestory window. The butterfl y
shades (Online Figure 2 ) act as a fi lter between
the exterior and interior spaces, reducing the effect
of glare from the east west low angle sun, omitting the
need for interior blinds and helping maintain the view
to external areas.
Daylight and glare simulations were conducted to
optimize the design of the butterfl y veil and balance
daylight availability and glare. The sky condition used
in the simulation is the standard CIE Overcast Sky. The
daylight simulation threshold was conservatively set to
1.0% daylight factor (DF) equal to 300 lux for at least fi ve
to six hours a day (based on an average overcast sky DF
to lux comparison).
Glare simulations were performed to detect potential
areas with high glare potential. For these areas with
higher risk of glare, venetian blinds were installed and
adjustable by users. High-performance, double-glazed
low E-glass of U-value 1.6 W/m2K (0.28 Btu/h· ft2 °F) and
SC value of 0.30 was selected for fenestration, replacing
single-glazed glass that was used before the renovation.
shades (
OPERATION & MAINTENANCE
The building is maintained by the Campus Asset
Management (CAM) department. Maintenance is
carried out periodically to ensure all equipment and
systems are performing at optimal levels. The staff
is trained to use the building management system
for the operation and control of the building services
equipment.
The design of the hybrid cooling system without
recirculation greatly reduced the complexity of the
ACMV system. Without return air ducts, about half
of the ducts are removed compared to a conventional
system. Ventilation units for hybrid spaces have a simple
confi guration with a fi ltration system (electronic air
cleaners), cooling coil, and fans wi th variable speed
drives that simplify the maintenance. All spaces
have exposed ceilings with acoustic spray for sound
absorption. The choice to remove all false ceilings
greatly simplifi es maintenance and monitoring as all
services are visible and easily access ible.
All space use and occupancy is tracked in real time
through indoor air quality sensors, temperature sensors
as well as occupancy sensors. Status of electrostatic air
cleaners is monitored in real time to ensure units are
running properly.
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ASHRAE JOURNAL ashrae.org MAY 2 0 2 4
COST EFFECTIVENESS
Through careful design consideration and the
push of a leaner renovation approach, the SDE1
renovation cost is $1,500/m2 ($139.40/ft2). The return
on investment (ROI) for the introduction of the
hybrid cooling system and controls is less than one
year due to operational energy savings and reduced
maintenance cost.
ROI of the photovoltaic (PV) installation has been
calculated to be less than seven years. Overall, the cost
increase to achieve net zero performance is calculated to
be 7%, with an ROI of less than six years.
ENVIRONMENTAL IMPACT
SDE1 is an adaptive reuse project where existing
building structures (i.e. foundation, slab, column and
roof) were retained while the façade, internal fi nishes
and all the building services were replaced. This
signifi cantly reduces the amount of waste and concrete
required as compared to full demolition.
A detailed life-cycle assessment (LCA) study
calculated the embodied carbon of the renovation to
be 175 kgCO2e/m2. The scope of the LCA was cradle-tograve
(A1 to C4), with service life of the building after
renovation estimated at 50 years (minor refurbishment
every 10 years, major ACMV and electrical renovation
every 20 years, including full replacement of PV panels
at year 25). The embodied carbon for the adaptive
renovation is about one-fourth that of a newly built
project and can potentially reach carbon neutrality
within 50 years.
The following design strategies allowed further
reduction of the project's embodied carbon:
 The decision to not install false ceilings reduced the
embodied carbon of the building by 10 tons.
 When conditions allowed, painted railings in
mild steel replaced the conventional stainless steel
used on campus.
 Reusing as much existing structure as possible.
 Using fabric ducts for air distribution.
 Using environmental product declaration to
carefully select products.
About 422 kWp (kilowatt peak) of solar PV with an
annual generation of about 464,277 kWh/yr has been
installed on the SDE1 roof. This can offset more than
100% of the total building energ y use based on measured
2022 electricity use. 
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