A zero carbon building is a building with zero net energy consumption or
zero net carbon emissions on an annual basis. In recent years, low/zero carbon
buildings have attracted much attention in many countries because they are
considered as an important strategy to achieve energy conservation and reduce
greenhouse gases emissions. Located at the heart of Kowloon Bay, the upcoming vibrant
premier business district in Hong Kong, ZCB is a green oasis in a densely
populated urban area.
ZCB is the
first Zero Carbon Building in Hong Kong. Developed by the Construction Industry
Council in collaborating with the Hong Kong Government, it aims to showcase the
state-of-the art eco-building design and technologies to the construction
industry locally and internationally and to raise community awareness of low
carbon living in Hong Kong. (HKCIC, 2012)
This ZCB generates on-site renewable energy from photovoltaic panels and
a tri-generation system using biofuel made of waste cooking oil and achieves
zero net carbon emissions on an annual basis. Beyond the common definition of a
‘zero carbon building’, ZCB exports surplus energy to offset embodied carbon of
its construction process and major structural materials.
Ecological systems
The building
has been designed passive as well as active systems to avoid emitting
carbonaceous substances, here are some of the main systems:
Wind Catcher
Wind catcher is a device that ventilates a building by the use of wind.
A small tower on the roof contains an opening that faces the prevailing wind,
which is at a cooler temperature than the interior of the building. Because the
wind velocity at this opening is greater than it is at the lower windows of the
building, air in the shaft of the tower is forced down the shaft to cool the
building.
Light Pipes
Light pipes are highly reflective tubes that capture light from domes on
the roof. They help bring light to windowless areas inside the building.
High Performance glazing
The high performance glass wall system offers good thermal and optical
performance to lower cooling load, reduces the reliance on artificial lighting
and hence reduce energy consumption. The reflecting shade inside the glazing
achieves this by reflecting heat and reducing heat again.
High-Volume-Low-Speed Fans
High-volume-low-speed fans can generate high volume of air flow at a low
speed. The noise associated with the movement of the fan blades is low. These
huge ceiling fans move large volumes of air effectively by using their patented
blade design, which enhances evaporation for comfort. The fan can effectively
reduce the necessary duration of air conditioning.
Active Skylight
The active skylight is a roof window frame set with inclined shading
fins. The skylights can be shaded if necessary to optimize daylighting and
solar control. The shading fins are controlled by computer software and sensors
by adjusting their shading angles to cut out direct sunlight at different
angles as the sun passes over the building. They diffuse daylight into the
interior as needed, greatly reducing the heat gain from direct sunlight.
Renewable Energy
In the ZCB, renewable energy is generated on site from solar energy by
photovoltaic (PV) panels and from biofuel (one kind of biomass) made of waste
cooking oil.
Other Features
-Main facade
facing south-east for higher potential to capture prevailing summer breeze
-Tapered built
form to create larger pressure differences on different building facades to
draw stronger air flow across the building
-High headroom
for key spaces to enhance stack ventilation effect
-Natrually
ventilated design at entrance to enhance ventilation effect
Based on the
above designs and technologies, the ZCB consequently does not increase the
amount of greenhouse gases in the atmosphere. It does at times consume
non-renewable energy and produce greenhouse gases, but at other times reduce
energy consumption and greenhouse gas production elsewhere by the same amount,
that’s why it introduce all these systems to achieve the goal of zero-carbon
emission.
Reference
ZCB Experience, viewed 30 May 2015, <http://zcb.hkcic.org/Eng/Features/map.aspx>
Tim Smedley, 2013, ‘Can zero-carbon
buildings become a reality?’, The Guardian, viewed 30 May 2015, <http://www.theguardian.com/sustainable-business/can-zero-carbon-buildings-become-reality>
