3.7
Between air-conditioning and no air-conditioning
Natural ventilation saves energy. When the weather is right, opening the windows to bring in fresh air is welcomed by
most people. However, a few important issues must be considered when providing natural ventilation in shopping malls
and shop spaces:
3.7.1 Humidity problem
Humidity in Hong Kong is the key deterrent to providing natural ventilation in shopping malls and shop spaces. While
the indoor temperature can be increased or decreased slightly through passive design to make it more comfortable or
suitable, humidity is extremely difficult to mitigate without any mechanical means. When the outdoor air is warm and
humid, condensation will appear on surfaces where the temperature is lower. This condensation might cause sweating on
shop windows, slippery floors and even long-term damage, including smells from mould or rotting decorations.
For the above reasons, it does not seem possible to rely on natural ventilation for tenants’ areas within a shopping mall
and for shop spaces except in the case of outdoor restaurants or displays of outdoor furniture in a furniture store.
The following discussion focuses mainly on providing natural ventilation within the common areas of a shopping mall and
shop spaces.
3.7.2 Possibilities for natural ventilation in shopping malls and shop spaces
A. Balcony shopping corridor
A balcony shopping corridor with shops on one side and open to outside air on the other is a common type of permanent
naturally ventilated shopping mall and shop spaces in Hong Kong. Excellent connections to the outdoors can be
achieved and this arrangement is particularly beneficial in attracting customers or when there are nice views.
Care, however, must be taken on the selection of finishing materials. Non-slip floor finishes are critical since the
floor might become dangerously wet with condensation. Shop front design is also needed to prevent the infiltration
of pollutants from causing damage to shop goods, decorations, etc. which might not be a problem in air conditioned
shopping malls and shop spaces.
B. Courtyards
Outdoor courtyards in shopping malls and shop spaces create interesting spaces and attractions. They provide
opportunities for festive functions, alfresco dining and break-out spaces for children and the elderly.
Open-sided courtyards are better than those that are fully enclosed in terms of natural ventilation. To capture more wind,
it is advisable to open up the courtyard from different directions and at different levels.
C. Hybrid ventilation
Creating air-conditioned shopping malls and shop spaces that can switch to a natural ventilation mode whenever the
weather and population density are suitable seems to be the ideal solution in the context of Hong Kong.
The simplest form of hybrid ventilation is daily adopted by most of us as we turn on the air conditioner when it is hot and
open the windows when it is cool. In its application to shopping malls and shop spaces, air conditioning and mechanical
ventilation systems are provided alongside operable vents and windows. The two systems work together through a
computerised control system to maintain internal comfort while using less energy. Hybrid ventilation uses the natural
system most of the time but supplements it with a mechanical system when the required comfort level cannot be reached
by the natural system alone. The mechanical system is usually a low-energy fan. Hybrid ventilation still allows occupants
to enjoy pleasurable external conditions at any time.
3.7
Between air-conditioning and no air-conditioning
3
Planning for shopping malls and shop spaces
94 Hong Kong Green Shop Guide
