Dr. B. V. Venkatarama Reddy

Professor, Dept of Civil Engineering,

Indian Institute of Science, Bangalore

THIS PRESENTATION WAS SHARED BY

FOR THE SESSION:

“Embodied Energy and the Life Cycle Approach”

DURING ANGAN 2019

B. V. Venkatarama Reddy Professor Department of Civil Engineering & Centre for Sustainable Technologies Indian Institute of Science Bangalore – 560 012, INDIA

3

Energy in Buildings & Sustainability – an overview

Lecture delivered at ‘ANGAN 2019’, 11 September 2019, New Delhi

Limited resources

Mass of resources:

6 x 1021 t

Planets Material & Mineral wealth •Limited •Non-renewable

The Planet Earth

Finite size

Emissions

Anthropogenic

activities

Mining resources

Prior 4400 BC till 1500 AD after 1800 AD

Zero Embodied

Carbon materials

Medium Embodied

carbon materials

High Embodied

Carbon materials

Global consumption of construction materials: > 60 billion t /annum

Per capita consumption: 8 t/annum (~6.5 t is aggregates)

Reddy BVV, SCMT5, 2019

Material resources

Exhaustible: Soil, Stone, Sand, Minerals & chemicals....

Renewable: Biomass - grasses, bamboo, wood… grown

Recyclable: Solid wastes - Industrial & mine ..

Sustainability?

There are many definitions for sustainability

6

Definition of sustainable development

Kumarappa (1945) “Economy of permanency” Brundtland report (1987)

Sustainable society:

Manages its economic growth without

causing irreparable damage to environment

Satisfies peoples’ needs without jeopardizing

prospects of future generations

Sustainable development:

Meeting the needs of the

present without compromising

ability of future generations to

meet their own needs

Prime focus in both these definitions is: • Sustainable extraction of resources from the planet earth • Without causing irreparable damage to the environment

… sustainability – renewable/regenerate

Pillars of Sustainability - Socio… - Economic.. - Environ..

Demand for Material resources

Mined resources

Sustainability ?????

Need for renewable resources

The planet hosts several living organisms • Human societies occupy ~2% of the planet’s surface

area but consume 75% of the planet’s resources (O’Meara 1999)

What is Green (construction)?

…green is about decarbonization!

refers to the changing relative amounts of carbon and hydrogen in

the fuels burnt to generate energy ….....(T. Bradford, 2006)

… about emission reduction

Type of fuel Carbon Hydrogen

Firewood Coal Oil Natural gas Hydrogen

10 2 1 1 0

1 1 2 4 1

Built Habitat/Environment

Consume •Energy •Material resources

Generate •Wastes •Emissions

45 50 60

0

20

40

60

80

100

120

Energy use Global waterconsumption

Global raw materialconsumption

%

[Willmott Dixon Group 2010]

By 2025, Buildings worldwide will be the largest consumers of global energy - greater than the transportation and industry sectors combined.

Agriculture

7%

Industry 44%

Transport

18%

Residential &

commercial

14%

Others

[PERCENTAGE

]

[CATEGORY NAME]

[PERCENTAGE]

India (2012) [Teddy 2013]

Energy in Buildings

Buildings

Energy for Materials &

Construction

Energy for

maintenance

Embodied Energy

Operational Energy

Operational Energy

Embodied Energy

11

Raw material

extraction

Building material

production

Construction

Operation, maintenance,

repair & refurbishments

Demolition &

Disposal

Initial Embodied

Energy

Recurring Embodied

Energy

Operational Energy

Demolition Energy

Embodied Energy

of building materials

& construction

Durability of material

Thermal performance

of materials/system

Building Life Cycle Life Cycle Energy

Life Cycle Energy (LCE) of a building

Attributes of building material

Praseeda et al. 2014, E&B, 2015

Embodied Energy (EE) – System Boundaries

[Dixit et al. 2010] 13

Methods for Embodied Energy Analysis

• Process analysis

• Input – Output analysis

• Hybrid methods [Menzies et al. 2008, Treloar et al. 2000]

14

Embodied Energy (EE) value depends upon

• System boundary considered

• Method of analysis

EE is not a unique value – it is a range

Process flow chart Raw Meal

Limestone Other raw

materials

Raw Mill Preheater

Kiln

Clinker storage

Cement Mill

Cement storage Packing & Dispatch

Gypsum

Fly Ash or Slag

Coal Mill Clinker cooling

Cement: Process of manufacture

15

Embodied Energy in Cement

Cement ready to dispatch to site EE of cement = 2.376 MJ/kg

Limestone Extraction

Mixing and grinding of raw

materials

Clinker production

Grinding of clinker

Packing and storage

Dir

ect en

erg

y

Indir

ect

energ

y

Sta

ge 1

Embodied Energy

Transportation energy

Other raw materials

Process Energy

0.032 MJ/kg

0.084 MJ/kg

2.26 MJ/kg

Praseeda et al. 2014, E&B, 2015

Embodied Energy in building materials

Type of material Sp. energy consumption

(MJ per kg)

Cement

Lime

Lime-pozzolana

Steel

Aluminum

Glass

3.00 - 4.00 (2.38 – 3.72)

4.75 – 5.75

2.00 – 2.50

42.0 (30)

236.8 (100 - 140)

25.8 (10 – 15)

Burnt brick

Hollow con. Block

Vitrified floor tile

1 – 2.5 (1.2 – 4.05)

0.60 – 0.75

5.5 – 6.5 (10.63)

Red colour highlighted – Praseeda et al. E&B 2015

Embodied Energy of burnt clay brick

Types of kiln EE (MJ/kg)

1 Clamps 1.7 – 2.9

2 Intermittent type 1.88

3 BTKs 1.20 – 4.05

4 CBRI improved BTK 1.51

5 Hoffmanns kiln 2.94

6 Downdraught kiln 3.36 – 3.48

7 VSBK 1.20

EE of burnt clay brick: 1.20 – 4.05 MJ/kg

18

0

1

2

3

4

51

2

3

4

5

6

7

8

9

10

11

12

13

14

Embodied Energyof Brick (MJ/kg)

Praseeda et al. 2014, E&B, 2015

Sl.

No. Climatic zone

Mean monthly

temperature (°C)

Relative Humidity

(RH) Regions

1 Hot and Dry Above 30 Below 55% Western & central part

2 Warm and Humid Above 30 Above 55%

Coastal regions Between 25 - 30 Above 75%

3 Temperate (Moderate) Between 25 - 30 Below 75% Pune, Bangalore

4 Cold Below 25 For any RH value Northern parts of India

5 Composite Six months or more do not fall within

any of the above categories

New Delhi, Kanpur,

Allahabad etc.

Embodied and operational energy in buildings

43 residential buildings in 4 climatic zones

(27 rural dwellings & 16 urban dwellings)

Designated as RD1 – RD27 UD1 – UD16

19

Embodied energy in rural and urban dwellings

EE of dwellings with natural materials is an order of magnitude lower than those with conventional brick-concrete

0.00

2.00

4.00

6.00

8.00

10.00

12.00

RD

4

RD

8

RD

14

RD

6

RD

23

RD

3

RD

15

RD

9

RD

26

RD

22

RD

27

RD

2

RD

21

RD

17

RD

1

RD

24

RD

19

RD

18

RD

7

RD

20

RD

13

RD

16

RD

5

RD

25

RD

11

RD

12

RD

10

UD

2

UD

4

UD

1

UD

16

UD

5

UD

6

UD

11

UD

8

UD

7

UD

15

UD

10

UD

9

UD

12

UD

3

UD

13

UD

14

1 2 3 4 5 6 7 8 9

Em

bo

die

d E

ne

rgy (

GJ

/m2)

Monolithic RC walls

RC frame burnt clay brick masonry

load bearing burnt clay brick

Rural dwellings with natural

and conventional materials

Source: Praseeda et al. E&B, 2016

Embodied energy = 11 GJ/m2

Monolithic RC walls Load bearing

brick masonry

RC frame burnt

brick masonry

EE = 4 – 6 GJ/m2 EE = 2.5 – 3.5 GJ/m2

Life Cycle Energy (LCE) in rural dwellings

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

RD

1

RD

2

RD

3

RD

4

RD

5

RD

6

RD

7

RD

8

RD

9

RD

11

RD

12

RD

13

RD

14

RD

15

RD

16

RD

17

RD

18

RD

19

RD

20

RD

21

RD

22

RD

23

RD

24

RD

25

RD

26

RD

27

Composite climate Warm & Humid climate Moderateclimate

Coldclimate

Lif

e C

ycle

En

erg

y (

GJ/

m2) OE for 50 yrs EE

EE represents 0.21 to 68% of LCE in rural dwellings

Source: Praseeda et al. E&B, 2016

Life Cycle Energy (LCE) in urban dwellings

0

2

4

6

8

10

12

14

UD1 UD3 UD4 UD5 UD6 UD7 UD8 UD9 UD10 UD11 UD15

Composite Warm & Humid climateModerateCold

Lif

e C

ycle

En

erg

y (

GJ/

m2)

OE for 50 yrs EE

EE represents 10 to 80% of LCE in urban dwellings

Source: Praseeda et al. E&B, 2016

Embodied vs Operational Energy

Urban dwellings from warm – humid and moderate climate zones

24

0

1

2

3

4

0 5 10 15 20 25 30 35 40 45 50

En

erg

y (

GJ/

m2/

yr)

Years

EE (UD9) OE (UD9) EE (UD10) OE (UD10) EE (UD11) OE(UD11)

EE < OE

EE > OE

Depends on

•Climate

•Conditioning type

•Envelope/materials

Source: Praseeda et al. E&B, 2016

Current rating systems

Attempt to address……… • Site planning, location & linkages • Design, materials & construction • Water & waste management • Awareness & education • Healthy living conditions

• Energy consumption, generation…

• Indoor environment quality, space conditioning…

Parameter Weightage

LEED-USA BREEAM - UK GRIHA-India

Materials, and construction methods

6 – 9%

13.5%

10%

Energy (consumption/generation,

Indoor environment quality,

space conditioning)

57%

39%

50%

Current rating systems

Attempt to link the concept of Green buildings to

Sustainable Construction

Energy conservation & pollution reduction Too much emphasis on

Little or less emphasis on:

• Conservation of dwindling basic material resources

• Environmental damage due to indiscriminate mining of materials 26

Sustainable habitat

Materials

Energy

Share of

sustainability parameters

in built habitat

Green Buildings address only • Part of the

sustainability issues

Reddy BVV, SCMT5, 2019

Major issues

Managing material resources

Minimising pollution – Energy

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Sustainable habitat

Thank you 29

Summary

• Consumption of construction material is alarming: 8 t (6.5 t aggregates) /capita/annum

• Sustainable constructions: should address both

the issues on energy & material resources

• EE: not a unique value – it is a range & dynamic

EE < OE

EE > OE

Details 30 - Storey concrete frame

2 - Storey brick wall

Total weight (t) 1,66,944 550

Built up area (m2) 92,903 251

Weight (t/m2) 1.79 2.19

Embodied energy (GJ/m2)

4.28 2.40

Weight & Embodied Energy of Building

Masonry

7.40%

Concrete

81.78%

Metal cladding

0.01%Ceramic

1.22%

Glass

1.17%Plastering

3.32%

Steel

5.10%

Ceramic

1.94%

Glass

0.10%

Granite

slab

0.60%

Concrete

37%

Stone

Masonry

22.60%

Brick

Masonry

29.07%

Steel

0.91%

Timber

0.42%

Plaster

6.94%

Distribution of mass

30 – Storey Building

2 – Storey Building

• Judicious use of material resources

• Use natural materials or effect changes with minimum energy expenditure – low carbon materials

• Reduce & recycle – think end of life utilisation

• Great need to use biomass based renewable materials

• Utilise solid wastes for construction products

Possible options for addressing issues on sustainable construction materials

32