By 2008, buildings accounted for 60% of greenhouse gas emissions in Hong Kong (with respect to the electricity generation and consumption). In order to promote environmental protection and sustainable building, the Construction Industry Council and the Hong Kong government presented the first Zero Carbon Building (ZCB) in Hong Kong, finished in 2012. It is a showcase eco-building of design and technology for the construction industry and for the community to raise awareness of low carbon living.
More than a building with zero net energy consumption on an annual basis, ZCB exports surplus energy to account for what was used during the construction and for the major structural materials. Among the amazing features of ZCB, three ideas are worth mentioning:
1. Sustainable Habitat: Landscape area.
To reduce the heat island effect by cooling the air and attract wildlife into the city, over 50% of the total site is greenery area. It includes an urban native woodland with 220 native trees and a constructed wetland with subsurface flow to recollect and treat rainwater with zero energy means to use in toilets.
2. Energy hierarchy priority
This approach divides energy in three steps: conservation, efficiency and production. First one is achieved by passive design, which leads to 20% of energy saving by taking advantage of the natural elements. The efficiency is given by the automatic window and cooling operations with real-time monitoring and a variety of innovative products, which include the High-Volume-Low-Speed fans, dessicant dehumidification and under-floor cooling. Energy efficiency by green active systems leads to an additional 25% of energy saving. Lastly, energy production comes from two sources: Bio-diesel tri-generation system from waste cooking oil and 600 solar panels.
The Bio-diesel system on ZCB has a 75% increase in energy use compared to conventional power plants as it is used for the electric and the adsorption chiller as well as for the dessicant dehumidification. Compared to a reference building, in a cloudy day in spring ZCB energy use is 98% lower and both sources deliver more energy than what is needed to power the building. The building is able to sell and distribute to the Hong Kong energy grid the energy that is left over after its internal consumption.
3. Climate responsive design
The building form and orientation is a product of research and modeling. Engineers studied the winds and solar trajectory in the site during summer and winter to maximize the natural window-to-window ventilation and to reduce exposure to heat gain. Also, the gradually sloping roof matches Hong Kong’s latitude to maximize energy capture for solar panels while it reduces light refraction for surrounding buildings.
Post in collaboration with Silvana Montoya. Part of the Low Carbon City Forum blog. http://www.LowCarbon.City
HKCIC. “The first zero carbon building in Hong Kong”. Building Journal. Hong Kong, June 2012, p. 30 – 44.
HKCIC. “ZCB” [Online since 2012] http://zcb.hkcic.org/ [Retrieved 20 April 2016]