3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Heat Island Research History,Countermeasures, Adaptation, andImplementation in Japan
Hideki TakebayashiaaKobe University

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Contents• Guideline for urban heat island measures by Japanese government• Evaluation and certification program in Japan• “Cool roof guidebook” published by Architectural Institute ofJapan• Reviews of contributions to this field by Japanese researchers• Conclusions and acknowledgements

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Guideline for urban heat island measures byJapanese government

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Guideline for urban heat island measures byJapanese government• The building design guideline for mitigating heat island
phenomena by Ministry of Land, Infrastructure, Transport andTourism, Japan• Evaluation tool similar to LEED “CASBEE-HI” by Ministry ofLand, Infrastructure, Transport and Tourism, Japan• The guideline for countermeasure against heat island by
Ministry of the Environment, Japan• The local government guidelines for urban heat island measures;
e.g. Tokyo, Osaka, …

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

The building design guideline by Ministry ofLand, Infrastructure, Transport and Tourism
Consideration example of building design based on the building design guideline for urban heat island mitigation

Sun ShadeVentilation

Surface coverage on site
Exhaust heat frombuilding equipment

Exterior materials of building(Source:
http://www.mlit.go.jp/kisha/kisha04/07/070716/01.pdf)
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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

CASBEE-HI• Mitigation effect is evaluated by heat island load Q (W/m2)• Adaptation effect is evaluated by SET* (oC)
QualityoC): adaptation
SET*(Q ：暑熱環境の緩和効果

25×(SQHI－１)

HI

BEEHI

＝＝

2
LHI：ヒートアイランド負荷

Q(W/m ): mitigation
Load
仮想閉空間
（ C .V.）

Quality (SET*(oC))

25×(5－SLRHI)

敷地境界内

Q H I: 歩 行 者 空 間 等 の
温熱環境の質の向上（暑熱環境の緩和）

内部空間

L H I： 仮 想 閉 空 間 外 へ のLoad

ヒートアイランド負荷

建物高さ

外部空間

2H 程 度

HQuality（計画敷地）Load

Q(W/m2)6

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Countermeasure techniques in guideline by Ministry of
the Environment for urban heat island measures
Mitigation of HI
Mitigation
Phenomena

Mitigation of Hot
Adaptation
Environment

Countermeasure techniques

DaytimeUse of Wind

Use of Planting

Use of Water

Use of Reflection
Artifical heatrelease
Dissemination,awareness raising

Sea breeze and mountain-valley winds
Wind from rever
A park and a green area
Roadside trees
Making green space on a parking
Making green space on a site
Roof greening
Wall greening
FountainPavement with permeable materials
Use of permeable materials to walls
Water sprinking
Mist
Pavement with heat barrier materials
High albedo roof
District heating and cooling system
Reduction of exhaust heat from a building
Reduction of exhaust heat from a car
Prevention of heat stroke by providing
information

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Nighttime Daytime
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Energyof
Reduction
EnergyConserNighttime Consumption
vation

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73rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Local government guideline menus for urban
heat island measures in JapanWindGreenWater

Reflection

Artificial Heat Release

Dissemination, awareness raising

100%Menus including energy-saving effectare desirable

90%
80%
Ratio [%]

70%
60%
50%
40%

Japanese prefer Green technology?

30%
20%
10%
BDGL

Kanjo 2

ShibuyaTakeshiba

NakanoMarunouchi

Shinagawa

Sakai

Hirakata

Osaka City

Chiba

Chiyoda Ward

Saitama

Osaka

Tokyo0%Source: S. Yoshida, T. Sato, H. Takebayashi,T. Tanaka, A. Mochida, R. Ooka, R. Yoshie,Investigation on differences among theguideline in Japan, Study on the proposal ofa countermeasure guideline against urban
heat island of each city in East Asia (Part 1),
Hokuriku branch of Architectural Institute ofJapan, 2013 (in Japanese)

Japanese consumers have various information about the countermeasures technology.
PrefectureCityDistrict8

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Evaluation and certification program in Japan9

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Evaluation and certification program in Japan• High reflectance paint, sheet, tile and water retaining material
are evaluated by the Environmental Technology Verification (ETVJapan) Program in Ministry of the Environment. However, they
are just evaluated and not certified. Consumers will select one
based on the evaluated performance which is listed on the web.
• High reflectance paint, sheet, tile, pavement are certified andlabeled by Osaka HITEC if its solar reflectance is larger than 0.4.
Currently, water retaining materials, exterior insulation, green
roof, reflectivity reduction by aging are considering for thecertification.

103rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Environmental Technology Verification (ETVJapan) Program in Ministry of the Environment
The ETV Program solves the marketing problem of advanced
environmental technologies, that are ready for commercial
application and are believed to be useful, but nevertheless are not yet
being widely used since as end-users such as local governments,
private enterprises and consumers, refrain from introducing themsimply because of the absence of an objective assessment of theirenvironmental conservation effects, etc.
(Source: http://www.env.go.jp/policy/etv/en/index.html)

Verification criteria related to urban heat island:
Sunshade adhesive films for glazing, sunshade coating materials forglazing, high reflectance paint for roofs and water retentive
materials for roofs
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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Certification program by Osaka HITEC(Heat Island Measures Technology Consortium)
Certification criteria• More than 40% of solar reflectance in initial value for high solarreflectance paint on the building rooftop; Authenticate 3 products• More than 40% of solar reflectance in initial value for high solarreflectance pavement except for roadway; Authenticate 5 products• More than 40% of solar reflectance in initial value for high solarreflectance sheet (membrane)• More than 40% of solar reflectance ininitial value for high solar reflectanceon the residential rooftop (tile, slate);
Certificate, logo, thermal load simulation
Authenticate 2 products

result are issued to the applicant company
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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

“Cool roof guidebook” published byArchitectural Institute of Japan13

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

“Cool roof guidebook” published byArchitectural Institute of Japan
Category of Cool roof

Cool roof

Green roof Water retaining materials

Technology to cool the city
by Architectural Institute of Japan

published in March 201414

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Cool roof guidebook
Cool roof
Effect on the rooftop
Tokyo Station Granroof

Yoyogi Gymnasium

Pacifico Yokohama

School roof

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Cool roof guidebook
Green roof
Namba Parks

Effect on the rooftop

Green wall

Green orbit

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Water retaining materials

Cool roof guidebook

Effect on the rooftop

water-retentive wall

Cool pavements

Effect on the pavement

Various urban surface

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Cool roof guidebook
Contents• Cool roof and urban heat island• High reflectance technology• Green technology• Evaporative technology• Performance evaluation method• Physical properties, parameters for performance evaluation
High reflectance paint, high reflectance pavement, high reflectancemembrane, high reflectance sheet, green roof, green wall, green
parking, green schoolyard, green orbit, water-retentive pavement,water sprinkling, water-retentive wall all over Japan are explained.
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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Other books on heat island measures in Japan“Technology and measuresof urban heat island”
edited by Prof. Moriyama(2004)“Architecture, urban andheat island, Vision andchallenge of measures”
edited by AIJ (2007)“Heat island measures,Concept and method tocool the city” edited bySHASEJ (2009)19

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Reviews of contributions to this field byJapanese researchers

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Countermeasures by cool roof

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Yasushi KONDO, et al. have developed the cool roof calculator and calculated thecooling and heating load in each city in Japan. Cool roof is effective in the region south ofTokyo.

Cool roof

Northern Japan

CoolingloadOsaka

Normal roof

HeatingloadTokyo

Cool roof calculator

Heating and cooling load (MJ/(m2year))

Kunihiro Udoh, Yasushi Kondo, Hitoshi Takeda, Simple evaluation system of cool roof for proper
promotion, AIJ J. Technol. Des. 31, 849-854, 2009 (in Japanese with English abstract)

Southern Japan22

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Masayuki ICHINOSE, et al. have assessed paint performance over time with respect tosurface contamination and degradation of reflectivity through environmental exposure
tests. They also confirmed the effects of washing on solar reflectivity.
Masayuki Ichinose, Takashi Inoue, Yoshihito Sakamoto, Long-term performance of high-reflectivity
exterior panels, Building and Environment 44 (2009) 1601–1608

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Ken-ichi NARITA et al. have investigated the mitigation effects of green spaces inurban areas by several microclimatic observations in Tokyo. A significant air temperature dropin an adjacent built-up area was observed within a range of 80–90 m from the boundary in thecase of Shinjuku-Gyoen Park.

Radiative cooling

Clear skycalm
Cold airGreen space

Built-up area

Air temperature (oC)

Ken-ichi Narita, Hirofumi Sugawara, Cold-air Seeping-out Phenomena in an Urban Green Space, Journal ofGeography 120（2）411–425 2011

Cold-air Seeping-out

Built-up area

Green spaceDistance (m)24

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Adaptation25

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Atsumasa YOSHIDA, et al. have presented a method for quantification and evaluation ofurban thermal environment in terms of feeling temperature or subjective thermal perception
through the use of a human energy balance model. In a steady state, and even in an unsteadystate with its variations in weather and human factors, thermal comfort values can generally
be obtained by using the overall human thermal load.
Yasuhiro Shimazaki, Atsumasa Yoshida, Ryota Suzuki, Takeshi Kawabata, Daiki Imai, Shinichi Kinoshita,
Application of human thermal load into unsteady condition for improvement of outdoor thermal comfort,
Building and Environment 46 (2011) 1716-1724

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Implementation27

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Hideki TAKEBAYASHI, Prof. Masakazu MORIYAMA et al. have examined the priority
for the implementation of urban heat island mitigation measures. Top priority concerns thebuildings with large roof areas. They also have examined on the appropriate selection ofurban heat island measure technologies to urban block properties.
Hideki Takebayashi, Masakazu Moriyama, Relationships between the properties of an urban street canyon
and its radiant environment: Introduction of appropriate urban heat island mitigation technologies, Solar
Energy 86 (2012) 2255–2262
Hideki Takebayashi, Yutaro Kimura, Sae Kyogoku, Study on the appropriate selection of urban heat island
measure technologies to urban block properties, Sustainable Cities and Society 13 (2014) 217–222
Street tree for sidewalk
Cool pavement for roadway28

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Takashi ASAWA, Prof. Akira HOYANO, et al. have developed a thermal design tool foruse in planning outdoor spaces by combining a heat balance simulation for urban surfaces,
including buildings, the ground and greenery, with a 3D-CAD system.
Takashi Asawa,, Akira Hoyano, Kazuaki Nakaohkubo, Thermal design tool for outdoor spaces based on heatbalance simulation using a 3D-CAD system, Building and Environment 43 (2008) 2112–2123

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Countermeasures, Adaptation by wind30

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Akashi MOCHIDA, et al. have developed the guideline for prediction and assessmentof the pedestrian wind environment around buildings in the design stage. It covers
Computational domain and representation of surroundings, Grid discretization, Boundaryconditions, Solution algorithm, spatial discretization, Convergence of solution, Turbulencemodels, Validation of user’s CFD model.
Yoshihide Tominaga, Akashi Mochida, Ryuichiro Yoshie, Hiroto Kataoka, Tsuyoshi Nozue, Masaru
Yoshikawa, Taichi Shirasawa, AIJ guidelines for practical applications of CFD to pedestrian windenvironment around buildings, Journal of Wind Engineering and Industrial Aerodynamics 96 (2008)
1749–1761

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014Outstanding contributions by Japanese researchers
Prof. Akashi MOCHIDA, et al. have revealed the relationship between the building density
and the average wind velocity at pedestrian level in residential neighborhoods. The
development method of guidelines for realizing acceptable wind environment in residential
neighborhoods using the gross building coverage ratio is proposed.
Tetsu Kubota,, Masao Miura, Yoshihide Tominaga, Akashi Mochida, Wind tunnel tests on the relationshipbetween building density and pedestrian-level wind velocity: Development of guidelines for realizing
acceptable wind environment in residential neighborhoods, Building and Environment 43 (2008) 1699–1708

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Yasunobu ASHIE, et al. have developed a high-resolution computational fluid dynamics(CFD) model, which takes into account complex urban morphology. Airflow and temperaturefields over the 23 wards of Tokyo were simulated with a CFD technique using a total of
approximately 5 billion computational grid cells with a horizontal grid spacing of 5 m.
Yasunobu Ashie, Takaaki Kono, Urban-scale CFD analysis in support of a climate-sensitive design for theTokyo Bay area, Int. J. Climatol. 31: 174–188 (2011)33

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Meso-scale model34

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Hideki KIKUMOTO, Prof. Ryozo OOKA, et al. have constructed a prototype of thefuture (2031–2035) standard weather data based on the Model for Interdisciplinary Researchon Climate (MIROC) and the Weather Research and Forecasting (WRF) model, then estimatedthe impact of climate change on the energy performance of a detached house.
Hideki Kikumoto, Ryozo Ooka, Yusuke Arima, Toru Yamanaka, Study on the future weather dataconsidering the global and local climate change for building energy simulation, Sustainable Cities andSociety, 2014, in press

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Hiroyuki KUSAKA, et al. have developed a simple, single-layer urban canopy model,and compared it to both multi-layer and slab models. This model is adopted in the WRF, it iswidely used worldwide.
Hiroyuki Kusaka, Hiroaki Kondo, Yokihiro Kikegawa, Fujio Kimura, A Simple Single-Layer Urban Canopy
Model For Atmospheric Models: Comparison With Multi-Layer And Slab Models, Bound. -Layer Meteor.,
101, 329-358. 2001

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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Implementation37

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Outstanding contributions by Japanese researchers
Prof. Masakazu MORIYAMA, et al. have proposed “Urban climate map” for planningsupport and held actual community planning workshop. And, participants of the workshop
have made proposals.
Takahiro Tanaka, Takuhiro Yamashita, Masakazu Moriyama, Community planning workshop by using“urban climate map”: Practice of workshop in the Komagabayashi neighborhood, Nagata, Kobe, J. Environ.
Eng., AIJ, 511, 91-98, 2007 (in Japanese with English abstract)
Urban climate map

Urban climate map

Climate analysis map Advice map
Information providing,
decision supportDecision making
Various planning, policyUrban planning Architecture planning
Urban policy
Town planning
Image of “Urban climate map” use38

3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Conclusions and acknowledgements• Guideline for urban heat island measures have been establishedby Japanese government and local governments• Evaluation and certification program have been implemented by
Ministry of the Environment and Osaka HITEC• “Cool roof guidebook” was published by Architectural Institute ofJapan recently. In this guidebook, recently history of heat island
research in Japan have been aggregated.
• Some parts of contributions by Japanese researchers to this field
have been introduced.
• I would like to thank everyone who provided information andsponsors from Japan (Miki Coating Design Office, Daikin
Industries, Ltd., Nippon Paint Co., Ltd., which are organized byHeat Island Institute International).
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3rd International Conference on Countermeasures to Urban Heat Island – Venice, October 13-15, 2014

Thank you for your attention.
Hideki Takebayashi
Department of Architecture, Graduate School of Engineering,
Kobe University, Japan
E-mail: thideki@kobe-u.ac.jp

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