Strategic Overview for Building Energy Efficiency
Preparing for the Next Decade International Conference on Energy Efficient Building Design
28th to 30th November 2016, New Delhi
Ashok B Lall
URBANIZATION TREND IN INDIA
NITI AAYOG PROJECTION OF DEMAND
-
10.0
20.0
30.0
40.0
50.0
60.0
2012 2017 2022 2027 2032 2037 2042 2047
Residential Space requirement (Billion m2)
Urban Rural
NITI AAYOG PROJECTION OF DEMAND
URBANIZATION TREND IN INDIA
URBAN HOUSING DEMAND
Currently 4-5 million households in the middle and low income categories
require housing in urban areas. Out of these 2.1 million homes are
required in seven major cities alone.
MAJOR SHIFT IN HOUSING TYPOLOGIES IN THE FORMAL HOUSING SECTOR
Embodied Energy
Embodied Energy: Building Structure & Finishes
Rationale Given that the window of opportunity for reversing climate
change has a horizon of the next ten years and also that the boom of residential building construction is expected to be at its height in the same decade , the contribution of embodied energy to CO2 emissions draws our attention .
Carbon dioxide emissions on account of the energy consumed
in production of residential buildings (Embodied energy ) , as against their consumption of the operational energy, will be significant in the context of rapid urban development .
This is on account on three factor
the adoption of construction materials compared to
traditional construction method
switch over to multistory frame construction using
reinforced cement concrete
relatively modest operational energy consumed in the
residential sector .
0
200
400
600
800
1000
1200
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
kWh
/m2
Years
Embodied Energy (kWh/m2) Operational Energy (kWh/m2)
At a conservative estimate the impact of embodied energy at the start of a residential buildings life is as much as operational energy spent over 10 years .
The Multiplier Effect of Embodied Energy in Construction Materials and Methods
COMPRESSED INTO ONE DECADE!
We can surmise that we have an explosion of CO2 emission on our
hands on account of high embodied energy methods of
construction
50% addition of built-space to existing stock
X
30% increase in embodied energy per unit area
X
over 63 cities of 1 million plus population today
Embodied Energy: Building Structure & Finishes
Methodology A data base of currently valid embodied energy in production
of materials in India taking into account improved industry practices was established .
Embodied Energy analysis of typical multistory building shows that
approximately 80 percent of the embodied energy of the total buildings is attributed to structural systems and external walls .
The structural and external walling systems embodied energy is calculated for following types of buildings using the construction materials data of a representative building of each type :
A. Building as usual - G+3 Hybrid Structure using burnt brick for walling . - G+8 RCC Frame With burnt brick infill . B. Environmentally conscious design - G+3 Hybrid Structure using load bearing Fly ash brick wall . - G+10 with Aerated Concrete Block Walling . Embodied Energy and Co2 Emissions per Unit area of net residential
space of the above examples is compared .
Embodied Energy Reinforcement steel - 27.3 MJ/Kg Cement - 3.2 MJ / Kg
Concrete
23%
Reinforcement
Steel55%
Brickwork
8%
Fenestration
6%Plaster
2%
Paint
2% Flooring
4%
Embodied energy %
Cement
18.35%
Sand
0.00%
Glass
2.19%
Stone
2.46%
Aggregate
1.20%
Steel
63.26%
Timber/Wood
0.27%
Bricks/Blocks
8.16%Others
4.11%
Cement
Sand
Aggregate
Steel
Timber/Wood
Glass
Stone
Bricks/Blocks
Others
Cost of materials
Cement
13.96%
Sand
3.39%
Aggregate
5.47%
Timber/Wood
16.36%
Steel
34.71%
Others
0.67%
Bricks/Blocks
7.43%Tiles
1.57%Stone
12.16%
Glass
0.29%
Ferro cement
concrete
3.98%
Cement
Sand
Aggregate
Timber/Wood
Steel
Ferro cement concrete
Others
Glass
Stone
Tiles
Bricks/Blocks
Material distribution by embodied energy % Material distribution by mass % Weight of materialsin kg
Others
1.34% Cement
7.75%
Aggregate
20.87%
Sand
15.95%Bricks/Blocks
44.18%
Steel
2.86%Stone
6.43% Timber/Wood
0.47%Glass
0.16%
Cement
Sand
Aggregate
Steel
Timber/Wood
Glass
Stone
Bricks/Blocks
Others
Cost distribution by material %
ANALYSIS
EMBODIED ENERGY IN CONSTRUCTION
Giving preference to low rise buildings (G+4) in residential
development and using low embodied energy materials for
external walling of a potential 20 -40 % reduction in EE/Sq. M. of
residential space compared to BAU .
For low rise buildings, considerable
reduction in
embodied energy
might be possible by
careful designing and
using materials with
low embodied
energy.
The range of CO2
emissions shows that in a well designed low
rise building emissions
are 30-40% less than an average high rise
building incorporating
a RCC frame
structure.
LOW EMBODIED ENERGY MATERIALS Options = Resilience
Growing dependence on refrigerant based air conditioning for thermal comfort.
Growing dependence on personalized motorized transport.
FUTURE OF THE URBAN MIDDLE CLASS
Sample Household Survey
The data for Abhiyan Apartments in Delhi (78 households) for the year 2007-08, 2008-09, 2009-10 shows a trend of increased average monthly electricity consumption per household.
LIGHTING 8%
KITCHEN 17%
AC 39%
CEILING FAN 17%
ENTERTAINMENT 16%
OTHERS 3%
There is an emerging trend of houses with EPI above 80 kWh/sq.m./year which are typically houses with 2 or more air conditioners and 4 or more occupants. This trend is visible in both climate types.
In a typical Chennai home air-conditioning and ceiling fans electromechanical aids for comfort consumes approximately 55 % of the energy bill .
Simple Passive Design : Insulate
Simple Passive Design : Shade
Simple Passive Design : Ventilate
3 ways reduction in air conditioning demand Lowering peak load Reducing diurnal period of demand Reducing seasonal period of demand
Simple Active Design : Integrate evap. cooling
Residential, Commercial, Institutional buildings Insulate Replace windows Add external adjustable shading LED Lighting Efficient radiant cooling system
PASSIVE UPGRADE ACTIVE RETROFIT
Residential, Commercial, Institutional buildings Insulate Replace windows Add external adjustable shading LED Lighting Efficient radiant cooling system
PASSIVE UPGRADE ACTIVE RETROFIT
INSTITUTE FOR RURAL RESEARCH & DEVELOPMENT, GURGAON
SOLAR ACCESS FOR SOLAR CITIES roof area to floor area ratio
TIME TO MANDATE ENERGY EFFICIENCY
Shade Ventilate Insulate
LEGISLATING AND MANDATING
Warn industry two years in advance of coming compliance standards
Make utility supply conditional on compliance
Global experience indicates that legislation is a must It starts with simple steps Can become more demanding progressively Takes at least a decade to alter market behavior and user expectations
LEGISLATING AND MANDATING
ADVANCING KNOWLEDGE Education, Training, Practice
INTEGRATION : Evaporative cooling and building mass - PROTOTYPE
On site T Beams and Hollow block
production for floor constructions
1. Vertical cooling ducts formed between
parallel load bearing masonry walls ,
which act as coolth stores .
2. Horizontal cooling ducts formed by
Precast Hollow Block floor construction ,
which also become coolth stores .
Evaporative cooling system
integrated with floor and wall
structure is a shared facility
between neighbors and requires a
co-operative management
arrangement.
P
Proposal for the REHAU core temperature control (CCTC) pipe size: RAUTHERM S 20x2,0mm pipe spacing: 15cm, pipe mounted on the lower reinforcement This piping layout of the CCTC is a first proposal, it has to be clarified: - occupied areas - distances to structural walls and beams - distances to ducts and air outlets - flow rate - position of the manifolds, in this proposal: manifold in the suspended ceiling below the chilled slab - pipe position in the concreted slab SECTION OF THE SLAB:
pipes near the manifold with a spacing of less than 15cm and pipes outside the chilled slab led in corrugated pipe The position and size of the space for air conditioning or air outlets has to be checked
RADIANT COOLING Plus Ceiling Fans
The planning of the structural system, external windows, placement of lights and fans in the slab and other services is such that each sub-divided space continues of receive: Radiant cooling for the RCC slab. Fresh Air Supply Daylight from the windows Artificial lighting Ceiling Fan Sprinkler system Fire Detector
REFLECTED CEILING PLAN
21
22.1
21.7
21.8
21
23.9
Air temp. 28.7
Air temp. 28.4
Surface temperatures Air temperature
INTEGRATION : refrigerant/ evaporative
cooling and building mass
Supplementary air velocity
I
INTEGRATION : at sub city scales - exploiting demand diversity and
temporal demand patterns and heat sinks
Residential, Commercial, Institutional buildings Insulate Replace windows Add external adjustable shading LED Lighting Efficient radiant cooling system
PASSIVE UPGRADE ACTIVE RETROFIT
Residential, Commercial, Institutional buildings Insulate Replace windows Add external adjustable shading LED Lighting Efficient radiant cooling system
PASSIVE UPGRADE ACTIVE RETROFIT
New Vaastu Shade
Ventilate Insulate
CONSUMER AWARENESS CAMPAIGN
THE EXTERNAL CHALLENGE
Nighttime land surface temperatures for Delhi, compiled from ASTER data for 2 October 2005 at 10:35pm, local time.
Source: Urban remote sensing for a fast-growing megacity: Delhi, India Netzband Maik and Atiqur Rahman
ENERGY INTENSITY OF URBAN FABRIC and UHI EFFECT
Source: (Memon, Leung, & LIU, 2007)
Controllable Variables
Urban Design and Structure related Population Related
Sky view Factor, Green Areas, Building Materials Anthropogenic heat, Air Pollution
UHI
Uncontrollable Variables
Anti-cyclone conditions, Season, Diurnal conditions, Wind
Speed, Cloud Cover
Scoping Study for Policy Initiatives to Minimize Urban Heat Island Effect for Low
Carbon Urban Growth
CAUSAL FACTORS OF UHI EFFECT
Building Building Building
Water percolation
Recharge of Ground Water
Building Building Building
Water percolation
Recharge of Ground Water
Building Building Building
Water percolation Reduction due to increase in hard surfaces
Building Building Building
Decreasing Ground water
Building
No Ground Water
Fully Air Conditioned! High Density Two Cars per Household
Vicious Cycle in full Steam !!
Water from Ganga
ENERGY INTENSITY OF URBAN FABRIC and UHI EFFECT
Compact
TREN
D
Incr
easi
ng
Ener
gy In
ten
sity
an
d U
HI
Dense Highrise
Building Building
Bengaluru Will be Unliveable in Five Years, Warns IISC Study
The IISC study claims that Bengaluru has witnessed an alarming growth of builtup area in the last 40 years.
The growth has been a phenomenal 525%. It also says that the vegetation of the once Green City
Bengaluru has seen a decline of 78%. The city also known as "Lake City" has lost 79% of its water bodies during the same period.
Vanishing lakes
A view Herohalli Lake. A view of Yelahanka lake
WATER SCARCITY
GLOBAL TEPERATURE RISE !
URBAN AIR AND NOISE POLLUTION
CITIZENS CONSCIENCE AND THE INFORMED CONSUMER