Buildings in Hong Kong account for over 90% of electricity consumption and 60% of total carbon emissions of the city. Over the years, we spare no effort to promote sustainable building design and adopt various state-of-the-art technologies to enhance energy efficiency and resource conservation in our development projects.
In 2014, we published the Sustainable Building Design Considerations Guidelines to provide a comprehensive guide for our designers to practise green and sustainable building design to improve our built environment. The Guidelines outline most of the important design considerations of the passive design in architecture and active design and provide useful references on sustainable construction materials and methods. We also developed a standard Particular Specification (PS) for the design of ArchSD temporary site office to further promote the use of green materials.
Passive Design in Architecture
Passive design in architecture is an approach to building design that uses the building architecture to minimise energy consumption and improve thermal comfort. We adopt suitable measures in the planning, disposition, orientation, building form and material selection to optimise interaction with the local microclimate. Our passive design in architecture strategies include:
Active design is an approach using the electrical and mechanical systems, such as heating, ventilation and air conditioning (HVAC) systems and lighting systems, to create comfortable conditions. These installations have significant influence over the energy use, greenhouse gases emissions, water use, thermal comfort and other sustainability outcomes of buildings. We have incorporated active design to improve the following aspects in buildings:
Construction and Materials
Apart from passive design in architecture and active design, adopting sustainable construction methods and materials also forms an important part in sustainable buildings. Common sustainable construction methods include prefabrication, pollution control during construction and the adoption of 3R principles (i.e. Reduce, Reuse and Recycle). In addition, we use sustainable materials such as recycled materials and timber from well-managed sources.
The building integrates a number of passive design in architecture and active design features which puts strong emphasis on energy conservation and greening. Lush landscaping was planted on the ground floor, elevated walkway and the roof. The office tower has a special vertical green belt on the building façades, a “green ribbon”, which comprised a series of vertical terraces climbing up the office tower to the roof garden. To maximise energy efficiency, the building is connected to the District Cooling System for air-conditioning. This feature also allows us to make use of more space on roof level for greening and photovoltaic panels.
The building achieves high thermal performance of building envelope by using double glazing as well as both vertical and horizontal sunshades. With this high performance façade system, the energy efficiency of air conditioning can be optimised.
Close up of the vertical sunshades (left) and application of sunshades in different areas of the façade (right) to reduce heat gain and glare.
In addition, the building equips with various renewable energy devices, including:
Diagrame showing the mechanism of solar chimney (left). It utilise solar heat to warm up the air at the top of an open shaft, thereby producing natural ventilation of occupied space under the shaft. Computational fluid dynamics diagram showing the induced air flow in the carpark (right)
Apart from the above design features, the building also adopted free cooling to office spaces, heat recovery wheel, brushless DC motors for fan coil units, heat recovery from condensate and lift regenerating power to reduce energy consumption and maximise energy efficiency.
Other environmental features adopted in the project include automatic refuse collection system, rainwater collecting and storage system, use of recycled materials, adaptive and modular design for office area, life cycle assessment on structural elements, dripping irrigation system and water saving sanitary fittings.
The building also features an education path to enable the public to understand and appreciate various sustainable features. Interactive display and signage totem have been established as part of the education path.
Environmental features map in the interactive display showing green features adopted and the benefits of the green features.
With all the above remarkable green building features, the building was awarded Grand Award for Buildings Under Construction in New Buildings Category in 2014 Green Building Award arranged by HKGBC. Also, the building has achieved Platinum rating in the Provisional Assessment Stage of the Building Environmental Assessment Method (BEAM Plus), and will be assessed under the Leadership in Energy and Environmental Design (LEED) certification programme.
In addition to adopting sustainable features in buildings, we also explore every opportunity to incorporate green elements during the construction stages. We applied various green features to build the construction site office for two schools located at Site 1A-3 and Site 1A-4 of Kai Tak Development. For example, recycled construction and demolition (C&D) materials such as broken concrete, concrete blocks and fill material were used to form site access and the footing of the site office. We also utilised various reused materials including structural steel, timber panels, bamboo, grille, concrete blocks, aluminium panels, tempered glass, etc. to build the site office to further reduce the use of virgin materials.
To create a pleasant working environment for the site officers, we transplanted an existing tree into the courtyard of the site office, and put a lot of potted plants in the office as well as established a green roof. Furthermore, the use of skylight and ribbon window allowed natural lighting entering into the office. A small fish pool was also set up as an amenity and to harvest rainwater for watering the plants. As one of our sustainable measures, we retained and reused about 50% of the materials or components of this construction site office in a special school project to conserve resources.
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