The meaning of zero carbon buildings for construction innovation and environmental design

近年世界各地都積極發展「零碳/低碳」建築，以達到節能減排及提高環保意識之目的。因為建築物是溫室氣體和碳排放的主要來源，所以未來建築節能和減碳排放成為大勢所趨。本論文深入剖析零碳建築的定義和相關概念，並且闡述了零碳建築的設計策略及意義，同時從建築和工程設計的觀點上，探討如何促進零碳建築的技術，以及在香港的發展情況。In recent years many countries in the world are developing zero-carbon/low-carbon buildings in order to achieve carbon emission reduction and improve the awareness of environmental design. Since the building sector is the major contributor of greenhouse gas and carbon emissions, therefore energy efficiency and carbon emission reduction in buildings have become an important trend for the future. This research paper investigates critically the meaning of zero carbon buildings and its related concepts. It also explains the design strategy and implications of zero carbon buildings. From the viewpoints of architectural and engineering design, the method to promote the technologies of zero carbon building is discussed and the current situation in Hong Kong is described.postprin

Energy benchmarking for buildings and plant engineering

Conference Theme: Sustainable Plant Engineering for Achieving Green and Environmental Friendliness Facilities in AsiaBenchmarking is the continuous activity of identifying, understanding and adapting best practice and processes that will lead to superior performance. It is becoming a key methodology for the assessment of energy efficiency opportunity. The process of energy benchmarking is very useful not only to building operation and management, but also to plant engineering and maintenance. By benchmarking the energy use, it is possible to set targets for promoting best practices and achieving better energy efficiency in buildings and industrial facilities. This research paper describes the basic principles of energy benchmarking and explains its significance to building facility management and plant engineering. As energy is important to every society and organization, it is believed that the benchmarking process can help evaluate performance, support decisions and facilitate improvements. The important issues and considerations for the implementation are discussed. It is hoped that more people can understand and make use of the benchmarking techniques to achieve sustainable facilities and plant engineering.postprintThe SOE Symposium 2010, Hong Kong, 10 July 2010. In Proceeding of the SOE Symposium, 2010, p. 87-9

高密度城市建筑屋顶绿化及都市农业

Invited paperMany urban cities in the world are trying to enhance sustainability by improving urban greenery and promoting urban farming. By installing green roofs with urban farming, it is possible to achieve environmental, social and economic sustainability for the buildings in urban cities because it can contribute to the mitigation of environmental problems, enhancement of community functions and development of urban food systems. This paper presents the findings of a research to investigate green roof urban farming for high-density urban cities like Hong Kong. The benefits and potential of rooftop urban farming are examined; some experiences in the world are described. The characteristics and constraints of high-density urban cities are studied and the situation in Hong Kong is evaluated critically. It is hoped that the research information will be useful to promoting sustainable buildings and environment in urban cities.世界上许多城市正在努力改善城市绿化和促进都市农业，以提高可持续性。通过安装绿色屋顶及都市农业，是有可能为城市建筑实现环境、社会和经济的可持续性，因为它可以有助于缓解环境问题，增强社区功能和发展城市粮食系统。本文介绍了一项研究结果，调查屋顶绿化及都市农业应用在像香港般的高密度城市之情况。探讨了屋顶都市农业的好处和潜力，并描述在世界上的一些经验。研究了高密度城市的特点和限制，也批判地探讨了香港的情况。希望这研究资料可以帮助促进可持续建筑和城市环境。postprin

Development of technical guidelines for green roof systems in Hong Kong

Green roof systems are living vegetation installed on the roofs and can provide many environmental and social benefits for achieving low carbon high performance building. This paper describes the major findings of a research to develop technical guidelines for green roof systems in Hong Kong. The current knowledge and latest trends of green roof technology in the world have been studied. Useful information and experience were examined for assessing the potential benefits and key design factors. By investigating the system components and practical considerations of typical green roof projects in Hong Kong and other countries, key information is established for preparing the technical guidelines. It is hoped that the research findings will not only fill in the information gap, but also enable the making of policy and strategy to promote better urban greenery and assess their performance systematically.postprintThe Joint Symposium 2010 on Low Carbon High Performance Buildings, Hong Kong, China, 23 November 2010. In Conference Proceedings, 2010, p. 1-

Green roof farming for buildings in urban cities

Invited paperMany urban cities in the world are trying to enhance sustainability by improving urban greenery and promoting urban farming. By installing green roofs with urban farming, it is possible to achieve environmental, social and economic sustainability for the buildings in urban cities because it can contribute to the mitigation of environmental problems, enhancement of community functions and development of urban food systems. This paper describes a research to investigate green roof urban farming for urban cities like Hong Kong. The benefits and potential of rooftop urban farming are examined; some experiences and examples in the world are described. The characteristics and constraints of urban cities are studied and the practical situation in Hong Kong is evaluated. It is hoped that the research information will be useful to promoting sustainable buildings and environment in urban cities. 世界上許多城市正在努力改善城市綠化和促進都市農業，以提高可持續性。通過推展綠色屋頂及都市農業，是有可能為城市建築實現環境、社會和經濟的可持續性，因為它可以有助於緩解環境問題，增強社區功能和發展城市糧食系統。本文介紹了一項研究，探討屋頂綠化及都市農業應用在像香港般的城市之情況。探討了屋頂都市農業的好處和潛力，並簡單描述在世界上的一些實際例子經驗。研究了城市建築的特點和限制，也探討了香港的實際情況。希望這研究資料可以幫助促進可持續建築和城市環境。published_or_final_versio

Assessment of thermal comfort in transitional spaces

Transitional spaces refer to those spaces located in-between interior and exterior environments acting as both buffer spaces and physical links, such as entrance canopies, foyers, lift lobbies, corridors, stairwells, etc. As transitional spaces may constitute a significant portion of the building volume and have large implications to occupants’ experience and building energy consumption, many research studies have come up in recent years to examine their conditions and characteristics. This research aims to investigate the thermal conditions and subjective thermal perceptions of occupants in the different types of transitional spaces. Semi-opened and fully enclosed lift lobbies and corridors in The University of Hong Kong (HKU) campus were chosen for the field study. Theoretical study, survey questionnaires and simple energy simulation have been implemented to examine the thermal comfort requirements, people’s perceptions and energy impact of transitional spaces. It was found that an opened area is easily influenced by variable weather conditions as it is close to natural environment while an enclosed one is totally separated from the exterior environment and commonly air-conditioned. This may lead to different subjective thermal responses in these two types of spaces. It was also discovered that people can accept wider thermal environment in transitional spaces and their thermal response varies with dressing, activity level, past thermal experience and prior thermal preference. It is believed that the current comfort standards and criteria are not designed for transitional spaces. The proposed thermal comfort ranges for transitional spaces were examined in this study using modified adaptive comfort model. This could be used to consider possible changes to the current design guidelines and standards. If the transitional spaces are designed with appropriate energy saving strategies such as passive design, hybrid ventilation and flexible HVAC controls, it can help achieve more energy efficient and healthy buildings in the future.postprin

Development of modular green roofs for high-density urban cities

Stream A: Lifecyle of implementing green roofs and green wallsMany cities are facing problems of urban heat island and lack of greenery space. Green roofs can help mitigate the adverse effects and bring the nature back to the urban area. To apply them effectively, it is important to evaluate the constraints and identify critical factors for planning and designing the green roofs. Modular green roofs have a good potential to suit high-density urban conditions because they can offer better flexibility, convenience and cost optimisation. This paper presents the research findings to develop modular green roof systems for high-density urban cities. Three different types of modular green roofs, including mat, tray and sack systems, were studied by assessing their designs and characteristics. The urban environment and typical buildings for green roof applications in Hong Kong were evaluated. Useful information was obtained to help design and select modular green roofs that can fit into high-density urban environment. In Hong Kong, the high-rise buildings have very limited roof spaces. It is usually more effective to apply green roofs to the top of medium- or low-rise buildings/structures or the intermediate podium roofs. For existing buildings, as they often have constraints on roof structural loading, it is necessary to select extremely lightweight systems. Modular green roofs can be designed to achieve this by adopting suitable vegetation and components. They can also provide greater flexibility for instant greening, future modification and maintenance. By optimising the manufacturing, nursery and installation processes, it is possible to reduce the unit cost of green roofs and allow wider spread.postprintThe 2008 World Green Roof Congress, London, 17-18 September 2008

綠色活牆在建築物的熱調節性能

Green living wall is an emerging new technology and a sustainable design strategy for high performance green buildings. By using the natural processes of the vegetation, it can provide the potential benefits for mitigating urban heat island, enhancing building’s thermal performance and improving air quality. For densely populated urban cities like Hong Kong, the space available for greening is very limited and green living walls can be applied to the exterior and interior surfaces of buildings to improve the city environment. This research aims to investigate the thermal regulation performance of green living walls. The basic principles and mechanisms of thermal regulation of green living walls were studied. The major characteristics of the heat transfer processes were evaluated and the key factors affecting the thermal regulation were identified. Theoretical models were developed for assessing the thermal regulation performance of different types of green living wall systems. It is hoped that the information obtained can offer useful knowledge and hints for designing and applying green living walls in urban cities.postprin

Thermal comfort and energy performance of chilled ceiling systems

Chilled ceiling systems are a relatively new approach to cooling and they have been applied in Europe and other countries for many years. The technology is based on ceiling-based radiant cooling panels coupled with chilled water pipes or coils. By combing convection and radiation, these systems have the potential to enhance thermal comfort and reduce energy use in air-conditioned buildings. This research studied the basic principles and key characteristics of chilled ceiling systems in order to assess their potential benefits on thermal comfort and energy performance. Field studies in two pilot projects in Hong Kong were carried out to investigate the system performance and practical considerations. Building energy simulation was applied to assess the potential benefits of the system on building energy performance. It is found from the field studies that the thermal comfort can be maintained in most of the time but some occupants feel that the air movement is sometimes too low. As compared with the conventional all-air systems, the chilled ceiling systems can reduce energy requirements by increasing chilled water temperature, decreasing supply air flow, downsizing air handling equipment and promoting higher room temperature. The results of building energy simulation show that the fan energy saving is the most important component and the percentages of energy saving for the HVAC system (19.8%) and the whole building (12.1%) are significant. 冷却吊顶系统是一个相对较新的冷却方法，在欧洲和其他国家已应用多年。该技术是基于冷冻水管道或盘管联结的天花板辐射冷却面板。这些系统通过结合对流和辐射，有潜力以提高热舒适度，并减少空调建筑物的能源使用。本研究探讨冷却吊顶系统的基本原理和主要特点，以评估其对热舒适性和节能性能潜在的好处。在香港的两个试点项目，进行了系统性能的调查和实际的考虑。并且应用建筑能耗模拟，来评估系统性能的潜在建筑节能好处。从研究试点项目发现，系统可以在大部分时间保持热舒适性，但也一些用户感到空气的流动有时过低。冷却吊顶系统与传统的全空气系统相比，可降低冷冻水温度增加的能源需求，减少空调供应送风量，削减空气处理设备，并促进更高的室温。建筑节能模拟分析结果表明，风机节能是最重要的组成部分，对空调系统(19.8%)和整个建筑(12.1%)的节能百分比结果是显著的。postprin

在建築地盤的熱應力和熱環境之研究

Heat stress is a recognized hazard for construction workers. To ensure safety and health of the workers, it is important to study the heat stress and thermal environment in construction sites, and develop practical solutions to avoid adverse health effects and accidents. In typical construction sites, the employees have to work long hours in thermally stressful environments, and with heavy physical workload, especially during summer time. As a result, they are at high risk and this may pose special hazards of heat stress. This research examines different kinds of heat stress indices and standards in the world. The result indicates that wet bulb globe temperature (WBGT) is a major factor affecting the level of heat stress because the rate of evaporation from human body is limited when WBGT increases. It is also found that some indexes provide little common agreement for the exposure limit and time; some can only be used for preliminary heat stress evaluation. In general, metabolic rate is the most difficult part to estimate in the heat stress equation for construction workers. It is concluded that engineering and administration method is the most effective way to control heat stress. Moreover, training and education for the employees are critical preventing accidents in construction sites.postprintThe Hunan-Hong Kong Joint Symposium 2011, Changsha, Hunan, China, 1-2 July 2011. In Proceedings of the Hunan-Hong Kong Joint Symposium, 2011, p. 52-612011湘港建築設備工程技術交流會, 中國, 湖南, 長沙, 2011年7月1日至2日. 會議記錄, 2011, p. 52-6