Urban Microclimate Design

in Hong Kong

Mr CHEUNG Hau-wai, SBS

Chairman, Hong Kong Green Building Council

28 April 2018

HKGBC Guidebook on

Urban Microclimate Study

A collaboration between HKGBC an

Chinese University of Hong Kong

CONTENT

1. Conception and Background

2. Study Scope

3. Guide for Microclimate Design

4. Key for Wider Application and Collaboration

5. Application beyond Microclimate

Climate Change in Hong Kong

Hong Kong's Climate Change Report (2015)

• Climate change is a critical

global issue and extreme

weather

• As mentioned in the Hong

Kong Climate Change Report

2015, Hong Kong will

experience increasing

extreme weather events

• Adoption of urban and

building designs

Hong Kong's Climate Action Plan 2030+ (2017)

Climate Change in Hong Kong

• Hong Kong Climate Action

Plan 2030+ emphasises the

importance of taking into

consideration urban climate

• High humidity and high

temperatures present the

greatest risk in causing heat-

related illness

Linkage to local credit system

31 UMC

Strategies

HKGBC Guidebook on Urban Microclimate Study

1. BEAM Plus embraces

planning, design,

construction, management,

operation and maintenance

of buildings

2. Microclimate design

required to address Site

Aspects for BEAM Plus New

Buildings

3. HKGBC commissioned the

Chinese University of Hong

Kong

• Provide rain

protection

• Increase evaporative

cooling

• Reduce heat

accumulation

• Reduce heat release

• Reduce direct

solar radiation

• Reduce surface

temperature

• Increase ventilation

with site planning

• Increase ventilation

with building design

UMC Design Guidelines

categorised into 8 approaches

The Guidebook provides a comprehensive tool

set for designers covering:

Increase ventilation with site planning

Kai Ching Estate

(1) Ventilation

Connect Open Spaces Arrange buildings to

channel wind

Long Ching Estate

Increase ventilation with site planning

(1) Ventilation

Building Set Back

Increase permeability of building blocks

Hysan Place

Increase ventilation with building design

(1) Ventilation

Permeable sky garden

URA's Kai Tak Development

Increase ventilation with building design

(1) Ventilation

to Increase building permeability - Create openings in building faç ades

Green Atrium

Increase ventilation with building design

(1) Ventilation

Increase ground zone air volume

1. Reduce heat discharge

near pedestrian area

2. Provide shading for

pedestrian activities

3. Provide water features &

greenery to increase

evaporative cooling

1. 2.

3.

(2) Public Health and Comfort

Outdoor open space

Increase ventilation

with Site Planning

(2) Public Health and Comfort Existing Building

Downwashed wind

captured by building

height difference Increase ground

zone air volume

with ventilation

bay or permeable

podium

Urban window to increase

building permeability

Increase ventilation with

Building Design

H/W > 4

Not effective

H/W < 2

effective

Reduce Temperature by Increase albedo

Reduce Temperature by

Reduce thermal mass

(2) Public Health and Comfort Existing Building

Reduce direct solar radiation Reduce surface temperature

Shading provided by covered walkway, tree canopies and

building blocks

Cool materials for ground surface and

green wall

Increase albedo and

sky view factor

(3) Radiation

Water features, greenery

and permeable paving Increase ventilation to carry away heat

(4) Heat Increase evaporative cooling

Reduce heat accumulation

Reduce heat release

Use light-weight external shades,

such as louvres

or green walls

Provide rain protection • Protecting pedestrians from precipitation will

improve the microclimate and usability of open

spaces.

• In designing a covered walkway, the angle of

deflection from the driving rain effect should be

considered.

(5) Precipitation

University

Industry Government

• Research

• Technology

• Education

• Practices

• Training

• Engagement

• Policies

• Incentives

• Public

awareness

University-Government-Industry Collaboration

Sustainable Development

Scientific Finding from the Collaboration

Govern-ment Industry

University

Our Way Forward…

Collaboration among

Universities,

Government and

Industry should ne

encouraged.

Govern-ment Industry

University

Our Way Forward…

General

Public

Investors

• Topical and Policy

issues

• Layman’s language

and Illustration

Stakeholder Engagement

1st Stakeholder Engagement meeting

(30 Sep 2016)

2nd Stakeholder Engagement meeting

(18 Apr 2017)

Platform for Government Departments, Industry and

Community to exchange views on issues of common interests.

Practitioners: • Consultants

• Developers

• Government

Departments (BD,

HKHA, DevB, EMSD,

EKEO)

• Universities (PolyU,

HKU)

• NGO (PGBC)

Problems in Hong Kong – Wall Effect

• Wall effect caused by

high-rise buildings along the coast, blocking the

ventilation pathways

across the urban area.

• Isolated high rise buildings

can improve ventilation of

surrounding area

• Districts with uniform

building height are worse

ventilated then those with

variable heights

Set Back

• Taking care of the health and

welfare of building occupants

and people on the street

• Mitigating and balancing the

need for development and

health and welfare

Microclimate Study

Hong Kong’s Contribution to

1) Hot and humid

climate region in

south east area

2) High rise and

density cities

Beyond Microclimate

Communal usage of precious natural resource - AIR

Communal usage of

1) Open space 2) Recreational area

3) Harbour promenade

4) Walking

Provide more design options and parameters for

1) Sustainable Building Design

Guidelines in APP-152

2) Planning Standard and Guidelines

relating to building height

[HKPSG Chapter 11]

Social Issues

Science

Solutions

Layman’s Language & Illustrations

Informed Public Opinion

Informed Decisions

Conclusion

Application beyond microclimate

Application beyond Hong

Kong to high density and tropical cities

HKGBC Guidebook on Urban Microclimate Study

Further Studies and Applications

HKGBC Guidebook on Urban Microclimate Study

For more information, please visit HKGBC website:

https://www.hkgbc.org.hk/eng/urbanmicroclimate.aspx

The full version of the Guidebook can be accessed at:

https://www.hkgbc.org.hk/eng/guidebooks.aspx.

https://www.hkgbc.org.hk/eng/urbanmicroclimate.aspxhttps://www.hkgbc.org.hk/eng/guidebooks.aspxhttps://www.hkgbc.org.hk/eng/guidebooks.aspx

Thank you!