ASHRAE Journal - March 2022 - 31

2022 ASHRAE AWARD OF ENGINEERING EXCELLENCE
DaiyaGate Ikebukuro, the fi rst tall offi ce building in Tokyo, Japan, connects to
Ikebukuro Station, the third-busiest railway station in the world. Tokyo has more
than a 70% chance of experiencing an earthquake with a magnitude of 7 or greater in
the next 30 years, and the high-rise was designed with resiliency in mind. It features
a new combination HVAC system of central air-handling unit (AHU) and perimeter
through-wall units (TWU), using exhaust heat recovery in the TWU for a highrise
building to achieve independent cooling/heating plus ventilation, along with
comfort and good air quality (Figure 1). The project received the 2022 ASHRAE Award of
Engineering Excellence.
This system, by successful integrative design, achieved
a healthy building that combines energy conservation,
resilience and indoor environmental comfort, considering
the health of the occupants and operational management.
The TWUs installed in the perimeter enclosure are
harmonized with the outer-braced structure, allowing
good daylighting and views and a high effective fl oor
area ratio (Figure 2).
Energy Effi ciency
The actual source energy use intensity (EUI) for the
entire building was reduced by about 58% compared
to the Japanese energy-saving standard and by about
44% compared to the ASHRAE Standard 90.1-2007. The
annual primary energy consumption
of the building was 1,043 MJ/m2·yr
(92 kBtu/ft2·yr), which is less than the
average value of 1,814 MJ/m2·yr (160
kBtu/ft2·yr) for offi ce buildings in
Tokyo. Japan. Key data and their contribution
to energy savings are shown
here:
1. The south core plan arrangement,
external walkways and bracing,
solar-tracking (automatically
controlled) blinds and low-e glass
dramatically improve the exterior
skin performance. The outer skin
performance resulted in the greatest
Shiro Tsukami, P.E.jp, is the engineering director of the
Building Services Design Division, Kitaro Mizuide, Ph.D.,
P.E.jp, is the executive offi cer and principal of the Building
Services Design Division, and Hirotaka Kubo, P.E.jp, is the
mechanical engineering of the Building Services Design
Division at NIKKEN SEKKEI LTD.
energy load reduction (28% reduction from the standard
value).
2. The heat source system for the AHUs consists of
air-cooled chillers and gas burning absorption chillers,
considering the functionality and redundancy of the
heat source system operation. A heat storage water
tank has been used to level the load and reduce peak
demand. The peak power demand of the building is
38 W/m2 (3.5 W/ft2), which is very low, because the
chilled water storage tank assists cooling demand
during summer peak hours (26% peak demand
reduction, compared to the case without the tank).
3. The heat source system was verifi ed for optimal
operation patterns using a life-cycle energy
FIGURE 1 Typical floor plan and HVAC zoning.
N
Offi ce
18.3 m (60 ft)
Through-Wall Unit (TWU)
Installed in Perimeter Enclosure
Exhaust Operation
By TWU
MR
Compact AC
Mechanical Room (MR)
18.3 m (60 ft)
Women's
Restroom
Intake Outside Air from the South Side Louver
61.8 m (202.8 ft)
Through-Wall Unit (TWU)
Air-Handling Unit (AHU)
Air-Conditioning Zone by AHU
M A R C H 2 0 2 2 ashrae.org ASHRAE JOURNAL
31
MR
Outdoor Air Route
Via Bypass Duct
Using TWU
18.3 m (60 ft)
Men's
Restroom
Elevator Hall
Elevator Hall
43.8 m (143.7 ft)
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ASHRAE Journal - March 2022

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