Figure 3.2.8 Perimeter air vent
(Source: Hysan Development Company Limited)
Figure 3.2.9 Illustration of natural
ventilation
(Source: Hysan Development Company Limited)
Outdoor Conditions Operation Mode
Under Automatic Control
Operable Vents
(except 33/F, 37-38/F)
Air-Handing Units
(AHUs)
21°C- 23°C or above Normal
Close
Normal
16°C- 20°C and Relative
Humidity (RH) <75%
Mode 1
Open
• Free Cooling
• Variable Air Flow
15°C or below
Mode 2
Open or Partially Open
(avoid over-cooling)
• Free Cooling
• Variable Air Flow
Mixed Mode Ventilation
Mixed Mode Ventilation combines
natural ventilation (via operable
vents) and mechanical ventilation/
air conditioning to provide and
enhance occupants’ comfort on
office floors. Once the vents are
opened, unnecessary air conditioning
to individual perimeter zone will be
automatically switched off without
wasting energy. The effective area
benefiting from natural ventilation
would be a 5m deep space behind the
façade.
Free Cooling System
Free Cooling System or Economize
Cycle uses oversized air handling units
and air ducts. Outside fresh air will be
used for direct space cooling without
using cooling towers during the right
outdoor conditions, distributing a
higher air volume at faster speed to
enhance the thermal comfort level for
occupants.
Figure 3.2.11 Exterior of H Queen’s
(Source: Henderson Land Development Company Limited)
Figure 3.2.12 Slide open wall of H Queen’s
(Source: Henderson Land Development Company Limited)
DESIGN STAGE
3.2.2 Adequate Ventilation
Case study of Hysan Place:
Operable Vent
In the right external conditions, occupants can open
top and bottom operable vents along the perimeter
zones of the office floors, then the combined wind
and stack effect will enable occupants to enjoy
natural ventilation. The vents provide a healthier
and more comfortable environment for staff
working after-hours or contractors doing fitting
out work. Occupants may enjoy natural ventilation
during the transition season or non-office hours
according to their own comfort and ventilation
requirements.
DESIGN STAGE
3.2.2 Adequate Ventilation
Office
BUILDING
Office
BUILDING
Case Study of
H Queen’s:
Slide Open Wall
A curtain wall façade with slide-
open modules on each floor
is designed to enhance cross
ventilation in interior spaces and
to facilitate artwork delivery. A
glass lift is introduced for better
social connections within the
building.
Figure 3.2.10 Mixed mode ventilation
(Source: Hysan Development Company Limited)
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