COOLING OUR CITIES

ADVANCES IN SCIENCE AND DESIGN FOR THE MITIGATION OF URBAN HEATScientia Professor Mat Santamouris,

The Anita Lawrence Chair in High Performance Architecture at UNSW Built Environment

COOLING OUR CITIES

ADVANCES IN SCIENCE AND DESIGN FOR THE MITIGATION OF URBAN HEAT

The thermal balance in the urban environment differs substantially than that of rural

areas. Anthropogenic heat released by cars and combustion systems, higher amounts of

solar radiation stored, and blockage of the emitted infrared radiation by urban canyons

makes the global thermal balance more positive and contributes to the warming of the

environment.

MAGNITUDE OF HEAT ISLAND MEASURED THROUGH URBAN TRAVERSES

Source : M. Santamouris Analyzing the heat island magnitude and characteristics in one hundred Asian and Australian cities and regions, Science of the Total Environment 512–513 (2015)

Source : M. Santamouris : Analyzing the heat island magnitude and characteristics in one hundred Asian and Australian cities and regions, Science of the

Total Environment 512–513 (2015) 582–598

INCREASE OF THE DURATION OF HOT SPELLS

URBAN HEAT ISLAND AND LOCAL CLIMATE CHANGE

THE EVIDENCE OF GLOBAL AND LOCAL CLIMATE CHANGE IN SYDNEY

Mat Santamouris, Shamila Haddad, Francesco Fiorito, Lan Ding, Deo Prasad, Wang Ruzhu, Paul Osmond, Xiaoqiang Zhai : Urban

Heat Island and Overheating Characteristics in Sydney, Australia. An analysis of Multiyear measurements, Sustainability,2017

UNSW – BE : Climatic and Energy Study of Western Sydney, 2019

THE IMPACT ON PEAK POWER DEMAND

`

The peak electricity demand of

electricity per degree of increase of the

ambient temperature varies from 0,4 %

for Tokyo to 4,6 % for Thailand.

In average, there is a penalty on peak

electricity demand of about 20 W per

person and degree of temperature

increase

Source : M. Santamouris et al C.

On The Impact of Urban Heat Island and Global Warming

on the Power Demand and Electricity Consumption of

Buildings–A Review, Energy and Buildings, 2015

THE IMPACT ON ENERGY

Source : M. Santamouris On The Energy Impact of Urban Heat Island and Global Warming on Buildings, Energy and Buildings, 82, 2014

N

THE IMPACT ON OUTDOOR COMFORT

Number of Days with PMV > 2 at 14:00

THE IMPACT ON INDOOR COMFORT – SYDNEY LOW INCOME HOMES

Source : UNSW – OEH Project on Energy Poverty,

THE IMPACT ON INDOOR COMFORT – SYDNEY LOW INCOME HOMES

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

12

35

46

97

03

93

71

17

11

40

51

63

91

87

32

10

72

34

12

57

52

80

93

04

33

27

73

51

13

74

53

97

94

21

34

44

74

68

14

91

55

14

95

38

35

61

75

85

16

08

56

31

96

55

36

78

77

02

17

25

57

48

97

72

37

95

78

19

18

42

58

65

98

89

39

12

79

36

19

59

59

82

91

00

63

10

29

71

05

31

10

76

51

09

99

11

23

31

14

67

11

70

11

19

35

Source : UNSW – OEH Project on Energy Poverty,

CO

2 C

on

cen

trat

ion

, (p

pm

)

Time Health Threshold

MORTALITY AND TEMPERATURE

+ 2 C +5.3 %MORTALITY ANOMALY

MORBIDITY AND TEMPERATURE

+ 2 C + 6.4 %MORBIDITY ANOMALY

MORBIDITY

IMPORTANT INCREASE HEAT MORBIDITY 2002-

2017

MORBIDITY

IMPORTANT RELATION MAX TEMP AND

MORBIDITY 2001-2017

+ 1 C + 4.6 %ABOVE 27 C, 1.1 % BELOW 27 C

MORBIDITY

MORTALITY OVER 65 YEARS OLD

INCREASES BY 5 % IN SUMMER BETWEEN

2002-2016

VULNERABILITY

THE HIGHEST VULNERABILITY LEVELS IN

PARRAMATTA ARE CALCULATED FOR THE CBD

AREA

HEAT RELATED MORTALITY AND MORBIDITY IN PARRAMATTA

EXCESS DEADTHS PER 100000 INHABITANTS DURING THE SUMMER 2016-2017

Source : CRC LCL : Heat Mitigation Study Western Sydney. Sydney Water, 2017

+ 4-5

C

2017

2050

2050 +

+ 1.0

C2017 HW

+ 1 -

4 C

UNSW – BE : Climatic and Energy Study of Western Sydney, 2019

The Future Consumption of Air Conditioning

The 2050 Cooling Consumption of Residential Buildings

0.00E+00

5.00E+12

1.00E+13

1.50E+13

2.00E+13

2.50E+13

Low Development ScenarioAverage Development ScenarioHigh Development Scenario

Res

ide

nti

al C

on

sum

pti

on

fo

r C

oo

ling

(kW

h)

750 %

2010

320 %2270 %

1620 %1330 %

2670 %

Source : M. Santamouris : Cooling the Buildings, Energy and Buildings, 2016

CURRENT AND FUTURE ENERGY CONSUMPTION IN SYDNEY

Source : UNSW BE Study on the Third City in Sydney

Heating

Cooling

CALCULATED HEAT RELATED MORTALITY IN 2050

CLIMATE CHANGE MITIGATION TECHNOLOGIES

To face the problem both mitigation

and adaptation plans have to be

undertaken.

Proper mitigation techniques should

include any anthropogenic

intervention to reduce the sources

and enhance the sinks of temperature anomaly

URBAN HEAT MITIGATION TECHNOLOGIES

Evaporative

Radiative Cooling

Cool Roofs

Wind Protection

Green Facades

Use of the Ground

AnthropogenicHeat

Other Heat Sinks

Control

Advanced Materials

Ventilation

Other Vegetation

Cool Pavements

Green Roofs

Smart Clothing

Trees

Nanomaterials

Development of

White Coatings of

Very High

Reflectivity

2006

A. Synnefa, M. Santamouris, I. Livada: Solar Energy, 2006

2007

Development of

Colored Infrared

Reflective

Coatings

A. Synnefa, M. Santamouris and K.Apostolakis : Solar Energy 2007

2011

Development of

PCM Doped IR

Reflective

Coatings

T.Karlessi, M. Santamouris, et al : Building and Environment, 2011

Development of Highly

Reflective Asphaltic

Materials

Synnefa A, T. Karlessi, N. Gaitani, M. Santamouris, Building and Environment, 2011

2015

Development of

Thermochromic Color

Changing Coatings

T. Karlessi, M. Santamouris, K. Apostolakis, A. Synnefa, I. Livada: : Solar Energy, 2009

T. Karlessi and Mat Santamouris : J. low Carbon Technologies, 2015

Development of

Retroreflective

Coatings

F. Rossi, B. Castellani, A. Presciutti, E. Morini, M. Filipponi, A.Nicolini, M. Santamouris :

Applied Energy, 2015

2016

Development of

High Reflective

Membranes

A.L. Pisello, V.L. Castaldo, G. Pignatta, F. Cotana, M. Santamouris : Energy and

Buildings, 2016

2017

Research on

Advanced

Elastocaloric

Materials

G. Ranzi and M. Santamouris : ARC Discovery Grant, 2017

2018

Research on the

Use of Quantum

Dots for Cool

Coatings

Research on the

Development of

Surfaces of High

Radiative Cooling -

Surface

Temperature below

the Ambient T

Research on Advanced Mitigation Material for the Urban Environment

Research on Advanced Mitigation Material for the Urban Environment

Colored IR reflecting Coatings

Source : A. Synnefa

M. Santamouris et al

On the development, optical properties and thermal performance of cool colored coatings for the urban

environment, Solar Energy 81 (2007) 488–497

Research on Advanced Mitigation Material for the Urban Environment

Colored IR reflecting Coatings

M. Santamouris et al : Cooling Parramatta, Not published article

Source : T. Karlessi, M. Santamouris, K. Apostolakis, A.Synnefa I. Livada : Development and Testing of Thermochromic coatings for Buildings and Urban Structures, Solar Energy, 2008

common

cool

thermochromic

thermochromic

cool

commonthermochro

mic

thermochromic Thermochromic coatings change color

as a function of the ambient

temperature.

For low outdoor temperatures (winter),

the coatings may be dark presenting a

high absorptivity. For higher ambient

temperatures (summer), the coating

becomes white presenting a high

reflectivity. Thus, when applied on

roofs or walls they may present the

best performance all year round.

Research on Advanced Mitigation Material for the Urban Environment

Thermochromic Coatings

Research on Advanced Mitigation Material for the Urban Environment

Thermochromic Coatings

Source : T. Karlessi, M. Santamouris, K. Apostolakis, A.Synnefa I. Livada : Development and Testing of Thermochromic coatings for Buildings and Urban Structures, Solar Energy, 2008

28.4°C

60.0°C

30

40

50

AR01

0

10

20

30

40

50

60

70

0:00 2:24 4:48 7:12 9:36 12:00 14:24 16:48 19:12 21:36 0:00

time

tem

pera

ture

(C)

Common

Cool

Thermochromic

59.7 C

54.8 C --- > 4.9 K

38.8 C --- > 20.9 Kcool

common

thermochromic

Black

Quantum dots (QD) are very small semiconductor particles, only several nanometers in size, so small that their

optical and electronic properties differ from those of larger particles. They are a central theme in nanotechnology. Many

types of quantum dot will emit light of specific frequencies if electricity or light is applied to them, and these frequencies

can be precisely tuned by changing the dots' size, shape and material, giving rise to many applications.

Research on Advanced Mitigation Material for the Urban Environment

Use of Quantum Dots for Mitigation ?

M. Santamouris and S. Garshasbi : Innovative New Generation Mitigation Technologies, SET 2018

Research on Advanced Mitigation Material for the Urban Environment

Use of Quantum Dots for Mitigation ?

M. Santamouris and S. Garshasbi : Innovative New Generation Mitigation Technologies, SET 2018

Research on Advanced Mitigation Material for the Urban Environment

Use of Highly Radiative Materials – Below the Ambient Temperature ?

M.Santamouris : Advances In Materials Science for Mitigation, Submitted for Publication, 2019

Future Development and Performance

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 5 10 15 20 25 30 35 40

Maximum Surface Temperature Drop

Max

imum

Am

bien

t T

empe

ratu

re

Dro

p

HR : Highly Reflective White Materials

HR

IR : IR Reflective Colored Materials

IR

IRB : Infrared Reflective AsphaltI

IRB

TC : Thermochromic Materials

TC

QD: Quantum Dots

QD

DRC: Daytime Radiative Cooling

DRC

Current Best

2025 Target

Annual Mortality per 100000 citizens

01

02

03

04

Cities presents 6- 10 C higher

temperature during the summer

period than the surrounding suburban

zones

Energy Consumption for Cooling

Purposes is increasing up to 100

% because of the local climate

change

Peak Electricity Demand

increases by almost 100 % when

temperature increase from 20 C

to 40 C

Heat related mortality can be up

to 300 % higher during the heat

waves period

THE PROBLEM

01

02

03

04

Mitigation techniques based on the

use of water, greenery, and cool

materials can reduce the average

peak ambient temperature up to 2,5

C. Advanced technologies may

decrease temperature up to 4 C

Mitigation techniques can reduce

the cooling needs of a residential

and office building up to 39 %

and 32 % respectively.

Application of Mitigation

Techniques can reduce the peak

electricity demand up to 10 %

Application of mitigation

technologies can reduce the heat

related mortality up to 40 % and

decrease heat realted morbidity

up to 45 % THE IMPACT OF MITIGATION

Future Challenges and Priorities

1. Cities Face Major Challenges : Overpopulation, Increase of the Boundaries, Climate Change,

Poverty, Slow Technological Development

2. Challenges and Problems have to be translated into Opportunities . Generate Wealth,

Employment and Promote Social Equity through the Eradication of Poverty, Mitigation of Climate

Change, Decrease of the Energy Consumption, Improvement of the Environmental Quality.

3. Research on Building Physics and Building Science should concentrate on the development of

break through and innovative technologies able to provide radical solutions at low cost

4. There is a tremendous future market, up to 2050, exceeding 100 trillion US$ for green and

efficient building products, systems and technology.

5. Only those having a vision, translated to a concrete research and development plan aiming to

develop innovative and appropriate technology will benefit and survive.