City University of Hong Kong Department Name

Green Building Performance

Green buildings are in promotion in Hong Kong. Since 1996, the Building Environmental Assessment Method (BEAM) has been introduced to this high-density high-rise subtropical city for green building assessment. On the energy use aspect, the BEAM assessment encourages integrative design of buildings and systems, and new provisions that improve energy efficiency and saving. More recently, the HK3030 initiative from the Hong Kong Green Building Council targets at a reduction of the building energy consumption by 30% in 2030, with the 2005 level of consumption as basis. To realize this goal, substantial improvement on building energy efficiency over the current situation is crucial. It becomes a whole building industry need of searching for different innovative techniques to fulfil the 30/30 target. The local building industry is also in need oiable fif releld measured data and convincing technical information to demonstrate the engineering practicality, energy saving potential, as well as cost benefits.

For large commercial buildings like offices, air-conditioning is in need most of the time. OTTV (overall thermal transfer value) evaluation is a useful statutory control measure. Green roof, other than the aesthetical and leisure effect on buildings, helps in reducing the temperature of the roof surface through the shades of the vegetation and evapotranspiration. Experimental projects were undertaken to investigate green roof as a bioclimatic strategy to improve building energy efficiency.

Other building features, such as the use of balcony, double skin facade, etc. were also investigated, in particular their implications on OTTV performance. Substantial reduction in heat transmission can translate into achievable comfort indoor environment with reduced electricity consumption of the air conditioning plant. It is most effective to implement the roof garden design at the early building project stage so that a holistic approach can be adopted to scrutinize various building sustainability issues.

Cross-section view showing the layers of construction of the green roof garden: Plot A – Zoysia japonica, Plot B - Ophiopogon jaburan, and Plot C – Duranta repens.

Daily temperature profiles at layers of green roof on typical sunny day

 

Related publications:

Journal articles:

Chan ALS, Chow TT, Fong KF, Lin Z. Investigation on energy performance of double skin facade in Hong Kong. Energy and Buildings, 41(11), 2009, 1135-1142.

Chow Tin-tai, Lin Zhang, Fong Kwong-fai, Chan Lok-shun, He Miao-miao. Thermal performance of natural airflow window in subtropical and temperate climate zones – a comparative study. Energy Conversion and Management, 50(8), 2009, 1884-1890.

Chan ALS, Chow TT. Investigation on energy performance and energy payback period of application of balcony for residential apartment in Hong Kong. Energy and Buildings, 42(12), 2010, 2400-2405.

Fong KF, Lee CK, Chow TT. Comparative study of solar cooling systems with building-integrated solar collectors for use in sub-tropical regions like Hong Kong. Applied Energy, 90(1), 2012, 189-195.

Chan ALS, Chow TT. Energy and economic performance of green roof system under future climatic conditions in Hong Kong. Energy and Buildings, 64, Sep 2013, 182-198.

Chan ALS, Chow TT. Evaluation of Overall Thermal Transfer Value (OTTV) for commercial buildings constructed with green roof. Applied Energy, 107, Jul 2013, 10-24.

Chan ALS, Chow TT. Calculation of Overall Thermal Transfer Value (OTTV) for commercial buildings constructed with naturally-ventilated double skin façade in subtropical Hong Kong. Energy and Buildings, 69, February 2014, 14-21.

Chan ALS, Chow TT. Thermal performance of air-conditioned office buildings constructed with inclined walls in different climates in China. Applied Energy, 114, February 2014, 45-57.

Fong SKF, Lee CK and Chow TT. Investigation on variable flow control in existing water-cooled chiller plant of high-rise commercial building in subtropical climate. HVAC&R Research, 20(1), 2014, 51-60.

Fong, SKF and Lee CK. Investigation on zero grid-electricity design strategies of solid oxide fuel cell trigeneration system for high-rise building in hot and humid climate. Applied Energy, 114, 2014, 426-433.

 

Conference papers:

Chan LS, Chow TT, Fong KF, Chu TCK. Application of cooling towers in existing buildings in Hong Kong. Proceedings of IAQVEC 2001, the 4th International Conference on IAQ, Ventilation & Energy Conservation in Buildings, Changsha, China, Oct 2001, Vol.2, pp.969-977.

Chan ALS, Chow TT. Study of water cooling schemes for commercial air-conditioning applications. Proceedings of CIB Working Commission 070, the Facilities Management and Maintenance Global Symposium 2002, Glasgow, UK, Sep 2002, pp.696-705.

Fong Kwong-Fai, Fong Ming-Lun, Chow Tin-Tai. Measurement and verification for performance contract of HVAC energy conservation in Hong Kong. Proceedings of the 4th Asian Conference on Refrigeration and Air-conditioning, Taipei, Taiwan, May 2009. (CD-ROM)

Chan LS, Chow TT, Fong KF, Lin Z. Investigation of urban heat island effect on the energy performance of buildings in Hong Kong. Renewable Energy 2010, Yokohama, Japan, Jun-Jul 2010. (CD-ROM)

Chow Tin-tai, Fong KF, Tse Norman, Fong Alan, Lin Zhang, Chan Apple. Studying energy audit via intelligent project studio. Proceedings of CLIMA 2010, the 10th REHVA World Congress, Antalya, Turkey, May 2010. (CD-ROM)

Chow TT. Energy use aspect of green building assessment in Hong Kong. Proceedings of High Energy Performance Buildings Workshop, DYNASTEE, Brussels, Belgium, 24-26 June 2013. (CD-ROM)

 

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