ASHRAE Journal - January 2023 - 49

TECHNICAL FEATURE
FIGURE 1 Energy end use breakdown in
kWh/m2·yr.
fl uorescent lighting with LED lights.
HVAC (Air Side)
23.58
Gas
17.88
Hot Water
0.78
Tenant Lighting
and Eqipment
38.22
Plug Loads
1
Lighting
3.82
Chilled Water
52.41
Fans
5.94
the facility's indoor environmental
quality (IEQ), where a survey reveals
84% of occupants giving highest
satisfaction ratings and 10% of occupants
giving near-to-highest ratings.
The 2021 energy audit and IEQ
surveys, both required by ASHRAE's
Building Energy Quotient (Building
EQ) and LEED O+M v4, were conducted
during the SARS-CoV-2
(COVID-19) pandemic.
With the detail of two ASHRAE
Level 1 Energy Audits conducted
by an ASHRAE Certifi ed Building
Energy Assessment Professional
(BEAP), both before and after the
building's renovation, and the
energy savings gained from implemented
energy conservation measures
recommended from the fi rst
audit, the project won the Energy
Genius Award.
Energy Reduction
The energy end use breakdown as
of the second audit in 2021 is shown
in Figure 1. The energy use breakdown
is based on utility bills for the
building and meter readings for
tenant areas.
The energy savings were achieved
through the following renovated
lighting and HVAC systems to
date, with ongoing phaseout of
Lighting
* Parking garage fl oor and staircase
area: T-5 fl uorescent light fi tting
controlled by building automation
system (BAS);
* Plant room: T-5 fl uorescent
light fi tting with manual control;
* Elevator lobby: LED downlights
(85%) and compact fl uorescent tubes
(15%) controlled by BAS;
* Communal area of offi ce fl oors:
LED downlights and light tubes
(85%) and compact fl uorescent tubes
with T-5 fl uorescent tube (15%) controlled
by BAS.
HVAC Systems
Heating System. The building air
conditioning heating source is provided
by two sets of gas-fi red boilers
with 2,500 kW (8,522,727 Btu/h)
heating capacity that are installed
in the boiler room. The hot water is
circulated through the hot water circulating
pump located in the above
fl oor water pump room to supply
hot water throughout the building.
Plate heat exchangers reheat supply
hot water for upper building offi ce
fl oors. Supply hot water is pumped
to fan coil terminal units delivering
heated airfl ow for perimeter spaces
of the north, east, south and west
sides of the building.
Cooling System. The building
air conditioning cooling source is
mainly provided by three centrifugal
chillers with total cooling capacity of
3,516 kW (1,000 tons) and two screw
chillers (Figure 2) with total cooling
capacity of 1,044 kW (296.6 tons)
to provide chilled water throughout
the building. Chilled water is
supplied through chilled water
pumps (Figure 3) to air-handling
FIGURE 3 Chiller pump room.
FIGURE 2 Chiller plant.
FIGURE 4 Typical air handling unit.
FIGURE 5 Typical cooling tower.
units (AHUs) at each offi ce fl oor
on the lower part of the building.
Afterward, the chilled water fl ows
through plate heat exchangers to
cool the chilled water prior to being
pumped to AHUs at each offi ce fl oor
in the upper part of the building
through secondary chilled water
pumps. A typical AHU is shown in
Figure 4.
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ASHRAE Journal - January 2023

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