ARCHITECTURE FACULTY
| Researcher : Lau SSY |
| Project Title: | A research on the calibration of local weather data for use in daylight design and prediction for tall buildings in densely built cities |
| Investigator(s): | Lau SSY, Chau KW, Rahim R, Baharuddin B, Chau Leung KC |
| Department: | Architecture |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2006 |
| Completion Date: | 12/2009 |
| Abstract: |
| To study and provide a detailed understanding of sky conditions of urban locations. Combined field and computer modeling of sky computer shall be adopted to quantify daylight distribution characteristics. High-rise residential apartments will be used as a proxy in the study and investigation; to focus on the architecture of computer simulation techniques involving data with presumably complicated or dynamic variables. |
| Project Title: | A study on the perception and psychology of daylight qualities of tall buildings in densely built cities - informing designers what users think |
| Investigator(s): | Lau SSY, Chau KW, Rahim R, Wittkopf SK, Baharuddin B, Ho DCW, Chau Leung KC |
| Department: | Architecture |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2007 |
| Completion Date: | 12/2009 |
| Abstract: |
| To study and devise a framework of socially-based criteria that measures user evaluation of environmental qualities (combining subjective and objective evaluation of daylight). |
| Project Title: | A research on the energy performance of an innovative window design for tall buildings in densely-built city environments |
| Investigator(s): | Lau SSY, Baharuddin |
| Department: | Architecture |
| Source(s) of Funding: | Small Project Funding |
| Start Date: | 01/2009 |
| Abstract: |
| I.1. Purpose Electric-lighting amounts to 30% of building energy usage. Recent researches demonstrated significant breakthrough in deploying daylight to minimize electric lighting. This proposal will verify the theoretical hypotheses and engineering model for Anidolic day-lighting application in tall buildings. Results will be published in a referred journal and for a new GRF application in 2009. If proven viable, the Anidolic theory could make a contribution towards the global sustainable city initiative by integrating energy-saving technology with building design for acute urban situations found in most densely-built cities. I.2. Background/key issues I.2.1. 1. Morphological character of densely-built cities, building heights and close proximity causing obstruction to daylight, is a negative factor for energy-saving daylight applications. In planning terms, the morphological characteristics of a compact city are: i. Density, high plot ratio and close-distance. ii. Vertical expansion that limits sky view; iii. Location effect that combines i) and ii) above; iv. Increasing building heights. HK has a staggering urban density -- 6,500 persons/sq. km. overall. Super-high-rise buildings inhibit daylight to reach the lower floors resulted in the reliance on electric lighting. The geographical character with 89% surface area being mountains and terrains, makes the setting worse. The combined result is an artificial or natural canyon where living spaces are deprived of daylight, natural ventilation and views. Fig.1, Urban character of a Compact City (photo by author, 2005) Figure 1: With taller buildings, it is pertinent to introduce energy-saving measures. 2. Lack of study on the interrelationship between climatology and building performance. For decades, our ancestors’ ability to design with nature has been displaced or neglected by materials or technologies such as high-performance glazing or air-conditioning. The missed opportunity by building designers presents a gap for this research – to propose an integrated climatic-responsive (daylight) building design technology. 3. Empirical study deals with the quantitative measure of daylight in the rear zone of interior spaces. Environmental benefits of fenestration will be measured. The social impact on users- task performance (glare) and psychological effects will be studied. However, there is a counter-argument that advanced daylight systems are costly to build and maintain while return might be marginal. Works by others and authors suggested otherwise. Below is a summary of their counter-arguments: 1. Courret, G., Scartezzini, J.-L, Francioli, D., Meyer, J.-J. “Design and assessment of an Anidolic light-duct” described the design/assessment of day-lighting performance in a prototype versus a conventional facade. Measurements (overcast sky) established that daylight factor on the work-plane 5 m from the window was more than doubled. Monitoring shown a saving of 30% lighting energy. Visual comfort measurements shown that visual quality is objectively improved at the rear work-plane. 2. Molteni, S.C., Courret, G., Paule, B., Michel, L., Scartezzini, J.-L. “Design of Anidolic zenithal light-guides for day-lighting underground spaces”, for underground spaces where windows are inadequate and skylights unsuitable, zenithal light-guides were used. Anidolic theory was tested and shown that it could improve the luminous performance. 3. Ochoa, C. E., Capeluto, I. G. (2006). “Evaluating visual comfort and performance of three natural lighting systems for deep office buildings in highly luminous climates.” Three different day-light systems for a side-lit office space were analyzed: a single window without any external protection, a horizontal light-shelf and an Anidolic concentrator. The Anidolic concentrator provided the highest illuminance levels. 4. Wittkopf, S. K. (2007). “Daylight performance of Anidolic ceiling under different sky conditions.” An Anidolic ceiling provided a more homogenized day-light distribution in the interior compared to other façade options, such as additional clerestory windows. 5. Wittkopf, S. K., Yuniarti, E., Soon, L. K. (2006). “Prediction of energy savings with Anidolic integrated ceiling (AIC) across different day-light climates” analyzed savings for different locations with Singapore representing a location of high sun altitude and high building density, while Sheffield representing a location of lower sun altitude and moderate urban density. Computational simulation shown a more than 20% saving in electric energy. Savings are quite similar for both locations. A. Work by us: 1. Ongoing RGC grants (Ref. HKU7205/02H and HKU7663/05H) helped the authors to accumulate knowledge of local conditions which involved over ten projects with architects to design building fenestrations for optimum daylight access to meet statutory requirements. 2. An example of the study -- an invited participation in the sustainability strategies (Anidolic system) for a swimming complex for a secondary school to improve day-light usage. Fig.3a, Isolux & False Colour simulation of daylight performance (Overcast Sky) Fig.3b, Light-pipe geometry (above) and enhanced Daylight Factor (DF) 3. Another work on the application of Anidolic theory on high-rise residential buildings using RADIANCE indicated a significant improvement in DF, DA, and Vertical Illuminance. Fig.4a, Example of densed development (above), and Daylight Factor performance (below) Fig.4b, Daylight Factor at working plane (above), and Daylight Autonomy (below) Fig.4c, Vertical illuminance in the right side of the wall (above), and the rear part (below) 4. Simulations by field measurement Fig.5, Quantitative parameters for day-lighting in high-rise buildings. 5. Preliminary Findings by us: - Results from Anidolic system in non-residential buildings (RADIANCE): o Reduces artificial lighting energy requirement of about 19% compared to an ordinary window system. o Improves the illuminance uniformity by 3.3 times of an ordinary window system. o Reduces the illuminance near the window by 30%, benefit for glare protection. o Reduces environmental impact by reducing the energy use of electrical lighting produced from fossil fuels. - The results from the application of Anidolic system in residential buildings (RADIANCE): o Improvement of 63.6% Daylight Factor (DF) at the working plane o Improvement of Daylight Autonomy (DA) at the working plane o Improves the vertical illuminance -- brightness of the wall in the rear part of a room. In summary, the objectives of this study include: 1. To investigate the theoretical (and technical) applicability of an advanced daylight system in a high-dense urban situation. 2. To quantify the benefits i.e. energy, health and sustainable benefits of the application of an advanced (Anidolic) day-lighting system. 3. Verify and formulate a theoretical framework and methodology for a full-scale research. |
| Project Title: | Quantifying the environmental performance of greenery in high density urban forms in sub-tropical cities - Hong Kong and Shanghai |
| Investigator(s): | Lau SSY |
| Department: | Architecture |
| Source(s) of Funding: | Seed Funding Programme for Applied Research |
| Start Date: | 03/2010 |
| Abstract: |
| Objective: The proposed project aims at investigating the environmental performances of urban greenery in different urban built forms featuring high-rise and high-density. The purpose of the study is to understand the strengths and limitations of urban vegetation in terms of environmental cooling in a high-rise high-density urban context, and to inform urban designers and architects in achieving a thermally-comfortable and energy-conservative urban environment. Buildings perform a significant role in energy-saving in recent global initiatives to reduce carbon dioxide emission. At the city scale, increasing governmental and community attention focus on the positive impacts of greenery as an active measure for shading, cooling, stress recovery; and more recently, carbon reduction for the design and operation of new and existing buildings -- for particular interest, in 2009 the Hong Kong Government has designated a reduction value of 23kg of CO2 per additional tree capable of reaching 5 meter height (the EMSD Carbon Audit Protocol, 2009). It is imperative for every player in the building and construction industry to be familiarized with theoretical and practical knowledge in the field of building science relating to greenery for buildings and cities. The research team at HKU Architecture has over the past 6 years carried out studies on the overall impact of urban heat island as it impacts local temperature and peak energy load for cooling. The study have covered both inner, coastal urban situations in Hong Kong and published a series of international journal papers on the understanding of the scope of problems for building design and layout for compact cities. Recent investigation focused on Shanghai which is praised for its advocation for urban greenery by imposing a stringent requirement for green ratio which is above the threshold of the national standard. The initial study have collected background information of the performance of urban greenery for different types of housing development (one international journal paper is in the press). The interest of the research team is to advance these initial studies of both cities to establish a common platform for wider industrial applications based on the comparison of building controls (by means of statutory requirements), design practice, local climatology, site factors, & human comfort preferences using existing and new data from HK and Shanghai. The 12-month study will assist in the preparation of a submission for a major local research grant, as well as international and local publications to publicize the knowledge for applied use by professionals. Industrial support has been sought by inviting two major industrial representatives to be team member to provide support in terms of validating the practical value of the knowledge. Hong Kong has its unique geographical features. Of the total land area of about 1000km2, 75% is mountains with flourishing vegetation covers. The urbanized area only account for about 15% and is mainly concentrated in Kowloon, north Hong Kong and some parts of New Territory. Stringent limitation on the buildable land results in an extremely high-density and high-rise urban form with deep urban canyons. Trees are hard to be found within these canyons but hundreds meters away from the urban center one can find green hills with dense vegetation cover. At the urban scale, the urban morphology may be in agreement with the concept of compact city which is thought to facilitate sustainability, but at the micro-scale ecological stress can be caused by high density. The lack of greenery at these urban locations could be a main contributor to the deteriorated environment. Shanghai, on the other hand, is a flat city without hills in it s domain. The urbanization process proceeds in the form of urban sprawl from urban center to its perimeter. Density decreases while greenery increases from the downtown to suburb areas. However at the inner city of shanghai, developers learns from Hong Kong experience on the multiple and intensive land use (MILU) pattern, and the traditional low-rise high-density Lilong housing is being replaced by high-rise high-density residential blocks on which stringent green ratios is stipulated by local codes. The impact of the evolving urban form on thermal environment remains unexplored. Therefore, the impacts of two distinct greening scenarios at the urban scale on thermal environment needs a systematic investigation. Key issues and problems to be addressed are as follows: 1) Review the evolution of urban environment and the challenge it poses on the role of green space in environmental cooling. There has been a trend of increasing density in urbanization progression in Hong Kong and other mega-cities in Asia, to accommodate ever-increasing population. For instance, currently developed real estates in Hong Kong are normally no less than 55 to 60 floors. The most commonly-found green open spaces in urban Hong Kong can be summarized into three types, i.e. pocket parks in mix-used street blocks, courtyard greening in enclosed mid-rise buildings and podium greening surrounded by interspersed high-rise towers. Research has shown that built form exerts impacts on the cooling performance of greenery (see next section). In response to the evolving density and urban form, the current paradigm of green space design needs a systematic review. 2) Evaluate existing urban greenery in various configurations. The thermal effect of greenery in influencing radiation, air temperature, humidity and air velocity is to be quantitative evaluated in relation to the built form and urban greenery. Thermal indices including mean radiant temperature (MRT) and physical equivalent temperature (PET) are to be calculated based on the measured data to quantitatively evaluate the impact upon human thermal comfort. A set of empirical models are to be derived including critical built form and greenery variables in predicting outdoor thermal environment and its impact on human thermal comfort. The models derived from Hong Kong are to be validated using data from Shanghai. 3) To recommend the optimal design schemes of green open spaces to meet the evolving urban form in Hong Kong and in Shanghai. Based on the results of quantitative evaluation, guidelines and optimal design schemes are proposed. The key issues cover the urban-scale ratio and distribution of green space, the optimal forms and sizes of green spaces inside the high-rise high-density urban context, and the suggested landscape design strategy (configuration of plant species, green ratio in the open spaces, etc.). Refer to the Attachment No.4: Reference, for the literature reference. |
| List of Research Outputs |
| Lau S.S.Y., (E) C40/Climate Dialogue Conference on Low Carbon Cities for High Quality Living, C40/Climate Dialogue Conference. Hong Kong, 2009. |
| Lau S.S.Y., Zhang Z. and Gou Z., (E) China Green Building Politics and Rating Label (Under Review), 中国绿色建筑发展政策与评价标识 (待发), Journal of Hong Kong Institute of Architects. 香港建筑师学报, 2009. |
| Lau S.S.Y., (E) Erice International Seminars on Planetary Emergencies (42nd Session), World Federation of Scientists and ICSC - World Laboratory. Erice, Italy, 2009. |
| Lau S.S.Y., Baharuddin and Gou Z., (E) Greenhouse Gas Emission Accounting for Buildings - An Introduction to Carbon Audit in Hong Kong, 建筑物温室气体排放审计--香港建筑物碳审计指引介绍, Energy of China [Class-A Core Periodical for Thesis in Science]. 中国能源, 2009, 30-33. |
| Lau S.S.Y., Baharuddin and Gou Z., (E) Greenhouse Gas Emission Auditing in Buildings, Energy of China. 2009, 31: 30-33. |
| Lau S.S.Y., (E) Paper Reviewer Invitation for Thermal Performance of a Vegetated Cladding System on Facade Wall (Ms. Ref. No.: BAE-D-09-00844), Building and Environment. 2009. |
| Lau S.S.Y., (E) Public Engagement on Building Design to Foster a Quality and Sustainable Built Environment - Forum on Sustainable Urban and Building Development, Council for Sustainable Development, University of Hong Kong. 2009. |
| Lau S.S.Y., Li F.M. and Baharuddin , (E) Qualitative Study on Window Design for High-rise and High-density Residential Building in Hong Kong (to be submitted), 2009. |
| Lau S.S.Y. and Gou Z., (E) Studying Comfort, Air-conditioning and Energy-use in Context, 'Sustaining Our Cool Living Heritage Workshop’. Malacca, 2009. |
| Lau S.S.Y., Gou Z. and Zhang Z., (E) Summary of Green Building Development in Hong Kong, China Architectural Journal. 2009, 11: 71-74. |
| Lau S.S.Y., Yang F. and Qian F., (E) Summertime Heat Island Intensities in Three High-rise Housing Quarters in Inner-city Shanghai China: Building Layout, Density and Greenery, Building and Environment. 2009. |
| Lau S.S.Y. and Baharuddin , (E) Validation of RADIANCE Sky Models against Local Sky Conditions of Hong Kong (Under Review), Energy and Buildings. 2009. |
| Lau S.S.Y., (S) 7th National Annnal Meeting of Postgraduates in Architecture & Urban Planning, 第七届全国建筑与规划研究生年会, Wuhan Huazhong University of Technology. 2009. |
| Lau S.S.Y., (S) 8ª Bienal Internacional de Arquitetura (Lecture, Juror, Exhibition), Brazilian Institute of Architects (IAB). Sao Paulo, Brazil, 2009. |
| Lau S.S.Y. and Wang J., (S) Hierarchical Production of Privacy: Gating in Compact Living in Hong Kong (to be submitted), 2009. |
| Lau S.S.Y., (S) Joint Hong Kong and Tianjin Conference for Sustainable Building Conference Proceedings, 香港天津可持續發展建築技術專業咨詢研討會論文集. Tianjin, 2009. |
| Lau S.S.Y., (S) Joint Hong Kong and Tianjin Conference for Sustainable Building, 香港天津可持續發展建築技術專業咨詢研討會, 天津. Tianjin, 2009. |
| Lau S.S.Y., (S) Reviewer for The Compact City Revisited, Perception of Urban Density: An Assessment of the Physical Parameters, Built Environment. 2009. |
| Lau S.S.Y., (S) SOCooLH Sustaining Our Cool Living Heritage, Residential Workshop, Melaka, School of Social and Political Sciences, University of Sydney, Centre for Advanced Studies in Architecture, National University of Singapore, Asia Research Institute, National University of Singapore. 2009. |
| Lau S.S.Y. and Hazelzet A.C.A., (S) Social Networks in Asian 'Enclave Cities: Lessons from Bangkok and Tokyo, The New Urban Question Urbanism beyond Neo-Liberalism, 4th Conference of international Forum on Urbanism, TU Delft. 2009. |
| Lau S.S.Y., Wang J., Gou Z. and Xu Z., (S) Teaching Social Sustainability at the Master of Architecture and Urban Design Studio at the University of Hong Kong (to be submitted), Journal of Architecture Education (JAE), USA-China [Class-A Core Periodical for Thesis in Science]. 2009. |
| Researcher : Lee ALC |
| List of Research Outputs |
| Lee A.L.C., Identity, In: Saywell, James, Hinge Magazine. Hong Kong, Hinge Marketing Ltd, 2009, 168: 8-10. |
| Researcher : Pu L |
| List of Research Outputs |
| Arner D.W., Chau K.W., Hsu B.F.C., Pretorius F.I.H. and Pu L., Regulating Credit Rating Agencies in Hong Kong: Lessons from the Global Financial Crisis, In: Professor Benjiman Geva, Banking and Finance Law Review. Toronto, Carswell, 2010, 25: 361-403. |