National Three-dimensional Garden City Building Seminar 13-18 Jan 2013, Shenzhen/Hong Kong/Macau, China (Senwa Hotel, Shenzhen) 讨 2013 1 13-18 ( ) Research on Green Roofs and Vertical Greening in Hong Kong 绿 顶 绿 1911-2011 Dr. Sam C. M. Hui Department of Mechanical Engineering The University of Hong Kong E-mail: cmhui@hku.hk 许
Contents 内 Introduction Potential benefits Green roof examples 顶绿 Vertical greening examples 绿 Major considerations 虑 Development trends 趋势 Conclusions 结论
Introduction Hong Kong Special Administrative Region (HKSAR) 别 区 Land area 积 : 1,104 km 2 Population : 7.06 millions Population density : 6,480 persons/ km 2 High urban density to meet population growth 应 Urban heat island and lack of greenery space 热岛 绿 问题 严
Introduction Promote green roofs and vertical greening to achieve urban sustainability 绿 顶 绿 现 续 Common types of roof greening: podium gardens and sky gardens 顶绿 : New greening techniques: 绿 术 Extensive green roofs 顶绿 Living walls & green facades 绿
A residential podium garden (Photos taken by Dr Sam C M Hui)
Podium garden (Kowloon Station) ( ) (Photos taken by Dr Sam C M Hui)
Sky gardens in commercial buildings (Kowloon Commerce Centre 贸 ) (HSBC Building Mongkok 汇 )
Another type of green roof in Hong Kong 绿 顶
Introduction Our research 们 * Started in 2002 2002 开 Assess the potential & impacts of urban greening 评 绿 Develop practical guidelines & information Promote education & technology development 进 (* See also http://www.mech.hku.hk/bse/greenroof/)
Introduction Examples of previous studies: Energy and environmental performance of green roofs and living walls 绿 顶 节 环 Design and assessment of modular green roof systems 顶绿 计 评 Life cycle analysis of green roof urban farming 顶绿 Feasibility study of green noise barriers 绿
Green roof research at a construction site office in Hong Kong 盘办 顶绿 (2002-2006) Green site office Modular design Green site office and typical site office Water sprinkler
Green roof research at a construction site office in Hong Kong 盘办 顶绿 Infrared pictures: Green roof Conventional roof
Thermal modelling of green roofs 绿 顶 导热 Radiation Transpiration Evaporation Conduction Radiation: Evapo-transpiration: Conduction: R n = R exp (-k s LAI) C p w T q" 2LAI ( ( r r ) h q ) / " ( Ts 1 Ts 2 e R i total m )
Study of modular green roof systems (2007-2008) 顶绿 Aluminum trays Wooden boxes Dry plant Plastic trays Wet plant Plastic trays (infrared photo)
Green roof systems from Germany (left) and Japan (right) 绿 顶 :
Introduction Current studies : Technical guidelines for green roof systems 顶绿 术 Technical guidelines for vertical greening systems 绿 术 Integration of green roof and solar energy systems 绿 顶 Evaluate indoor living walls 内 评 HK green roof policy 绿 顶
Typical structure of extensive green roof 顶绿 结 Vegetation Growing medium Filter membrane Drainage layer Waterproofing membrane Support panel Thermal insulation Vapour control layer Structural support
Integration of green roof and solar energy systems 绿 顶 (Photos taken by Dr Sam C M Hui)
Infra-red photos of vertical greening 绿 红 线 Bare wall Living wall
Potential benefits Green roofs & vertical greening 绿 顶 绿 Building integrated vegetation 综 Urban cityscape 观 Green infrastructure 绿 础 Possible benefits: 1. Environmental 环 2. Economic 3. Social
Potential benefits 1. Environmental benefits: 环 - Mitigate urban heat island 缓 热岛 - Improve air quality 质 - Stormwater management - Create natural habitat - Increase biodiversity - Insulate and absorb sound - Possible urban farming
Urban heat island in Hong Kong 热岛 区 乡 (Source: SCMP and Hong Kong Observatory)
(Source: www.accuweather.com) Rainstorm flooding problems in Hong Kong (2008) 问题
Potential benefits 2. Economic benefits: - Improve roof durability 顶 - Increase roof material lifetime 顶 - Reduce building cooling load and energy costs 负 - Provide open space & increase property value 开 - Green building credit points & image 绿 评
Thermal properties of green roofs 绿 顶 热 Outdoor Evapo-transpiration Shading Thermal mass Insulating property Roof slab Indoor
Potential benefits 3. Social benefits: - Aesthetic for city space - Provide community green space & gardens for sports & leisure 区绿 娱乐 - Community participation 区 积 - Provide education opportunities - Enhance local employment
School education green roof project 顶绿 (Source: Ng Yuk Secondary School)
School education green roof project 顶绿 (Source: Environment and Conservation Fund)
Urban Agriculture Green Roofs 顶绿 Urban Greenery 绿 Food System Green Building 绿 City Environment 环 Sustainability 续 Environmental 环 Social Economic
Green roof examples 顶绿 Green roof application is growing fast in Hong Kong in recent years 顶绿 应 来 1. Government projects (as demonstration) 项 ( ) (> 250 nos.) 2. School projects (with incentives/subsidies) 项 ( 奖励 / 贴 ) 3. Private projects (for green image) 项 ( 为 绿 )
Examples of green roofs in Hong Kong 顶绿 Ocean Park EMSD Headquarters Parklane, TST (Photos taken by Dr Sam C M Hui) HK Wetland Park 湿
Hong Kong Wetland Park Phases II 湿 (Source: Architectural Services Department)
Greening at Tamar project 舰 绿 (Photos taken by Dr Sam C M Hui)
(Source: ArchSD) New prison: green roof 监狱 顶绿
Government green roof projects 绿 顶项 Sewage treatment plant Refuge room Sewage pumping station (Source: Drainage Services Department and Housing Authority)
Roof greening on covered walkway 顶绿 (Photo taken by Dr Sam C M Hui) (Source: Housing Department, HK)
(Source: Architectural Services Department) School green roof project 顶绿
(Source: Architectural Services Department) School green roof project 顶绿
HKU Centennial Campus (Photos taken by Dr Sam C M Hui)
Introduce greening on existing rooftops 现 顶 绿 (Source: Development Bureau, HK)
Kai Tak Cruise Terminal 码 (Source: http://inhabitat.com and Development Bureau)
Vertical greening examples 绿 Common reasons for vertical greening 绿 : Aesthetic (how it looks) ( ) Cognitive (meaning) 认 ( ) Experiential (use) 验 ( ) Planning and financial gains ($) 规 财 Pollution absorption (air) ( ) Ecology (habitats) 态 ( )
Vertical greening examples 绿 Application methods of vertical greening 绿 应 : 1. Building façades or outdoor vertical surfaces 2. Interior walls or indoor vertical surfaces 内 内 3. Noise barriers (e.g. along the roads) ( ) 4. Slopes
An example of vertical greening 绿 (Source: CityWalk, Tsuen Wan, 湾, www.citywalk.com.hk)
An example of vertical greening 绿 (Source: CityWalk, Tsuen Wan, 湾, www.citywalk.com.hk)
A green wall in Central 环 绿
A green wall project in Kowloon Bay 湾 绿 (18 Kowloon East)
(The Hennessy) A green wall project in Wanchai 湾 绿
(Source: www.greening.gov.hk) Green wall for exhibition function 览 绿
Government demonstration projects 项 For a housing estate For a school building (Source: www.greening.gov.hk) For a government building (EMSD Headquarters)
(Source: www.everplant.com.hk) A school green wall project 绿 项
(Source: Hotel ICON) An indoor green wall in a hotel 内绿
Indoor green wall 内绿
(CityWalk 2, Tsuen Wan, 湾 2 ) Indoor green wall 内绿
Indoor green wall 内绿 (International Commerce Centre 贸 ) (Photos taken by Dr Sam C M Hui) (International Finance Centre )
(Source: Highway Department, HK) Green noise barrier 绿
(Source: Highway Department, HK) Greening on highway structures 绿 结
(Source: Civil Engineering and Development Department) Greening on slopes 绿
(Source: www.centamap.com)
Major considerations 虑 High-rise buildings: very limited roof spaces 层 顶 Better to apply green roofs to medium- or low-rise buildings/structures or podium roofs / 顶绿 Podium/sky gardens Structural loading 结 载 Determine validity and cost For existing buildings 对 现 Light-weight greening systems 轻质绿
Green roof on a low-rise building 层 顶绿 (Source: Hongkong Electric Co., Ltd.)
Major considerations 虑 Climatic factors Typhoons: strong wind might blow away the vegetation and soil Heavy rainfalls: hold and drain the rain water without creating pools of stagnant standing water 积 High temperature: affect some plant species Strong sunlight: solar and UV radiation 线辐
Infrared photo for assessing thermal effects 评 热 应 红 Typical hardy plants (sedums) used for green roofs 绿 顶
Major considerations 虑 Costs and commitments 诺 Capital cost (direct & indirect costs) 资 ( ) Recurrent maintenance costs 维 养费 Life cycle costs Risk of failure costs 败 Maintenance commitments 维 诺 Ownership 权
Major considerations 虑 Technical guide: 术 * 1. Introduction 2. Scope 围 3. Definitions 4. Planning Requirements 规 5. Design Considerations 计 项 6. Construction Methods 7. Maintenance Issues 维 问题 8. Project Management 项 (* See also http://www.mech.hku.hk/bse/greenroof/)
Development trends 趋势 Sustainable technologies Rainwater harvesting Renewable energy (e.g. solar photovoltaic & wind) Composting (for producing fertilizer) Farming and food production Agricultural green roofs Edible living walls
Integration of green roof, rainwater recycling and renewable energy 顶绿
Integration of green roof and solar energy systems 绿 顶 (Source: www.zinco.de)
Sustainable rooftop farming 续 顶 Wind energy Greenhouse Composting Solar energy (Source: www.skyvegetables.com) Rainwater harvesting
Green roof research with integrated systems 绿 顶 综 Micro-wind turbines Rainwater recycling Modular system 绿 顶 Built-in system 绿 顶 Space for green roof research and urban farming 绿 顶
Urban farming on green roofs 绿 顶 Farming on the roof 顶 Vegetables and herbal plants Water melon Green beans (Photos taken by Dr Sam C M Hui; Acknowledgement: St. Bonaventure Catholic Primary School )
Conclusions 结论 Green roofs and vertical greening are developing fast in Hong Kong 顶绿 绿 New techniques are applied to urban greening 术应 绿 More research is needed to determine suitable technologies and policy for promoting them 术 进 绿
THANK YOU 谢!! (More information: www.mech.hku.hk/bse/greenroof/)