Energy efficiency in buildings
Case studies from around the
world
Case studies and most slides prepared
for ESCAP by Prof. B. Mohanty
Around 50% of all electricity is
used in buildings
Source: OECD/IEA, 2008, Energy Technology Perspectives 2008
Energy and buildings
Pre-construction
Construction
Operation
Demolition
Demolition
Site Assembling
Power plant
Materials
Extraction
Transport
Electricity-HVAC
Solid waste
50-100 years lifetime!
 During building construction & renovation (Embodied energy in the building materials, Energy
needed during construction & renovation process)
 During building operation over its life span (Energy to achieve thermal and lighting comfort, Energy
needed for types of appliances)
Slide prepared for ESCAP by Prof. B. Mohanty
P4
Embodied versus operating energy
Manufacturing
1. Indirect
2. Direct
Embodied
Energy
Operating
Energy
Linkage
Poor design, less comfort, higher electricity consumption
By combining different techniques, small increases in embodied energy
will greatly decrease operating and total energy use
S5
Best practices and exemplary buildings
 Low energy office building: Malaysia
 Key data
 Gross floor area: 20 000 m2
 Energy performance index: 114 kWh/m2/year
 Addition cost to construct: 5%
 Annual energy savings: RM 600 000
 Payback period: 5 years

Energy efficiency features
 Orientation & building
envelope insulation
 Energy efficient lighting,
ventilation & office appliances
 Energy management system
Ministry of Energy, Water & Telecommunications, Malaysia
6
Malaysia Energy Centre
 Zero energy office building
 Key data
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Gross floor area: 4 000 m2
Energy performance index: 35 kWh/m2/year (excluding solar PV)
Energy performance index: 0 kWh/m2/year (including solar PV)
Addition cost to construct: 21% (excluding solar PV)
Addition cost to construct: 45% (including solar PV)
Payback: <22 years
Malaysia Energy Centre
 Energy efficiency features
 Building envelope
insulation & double glazing
 Almost 100% day-lighting &
task lighting
 Energy efficient ventilation
& floor slab cooling
 Energy efficient appliances
 Energy management system
S7
Best practices and exemplary buildings
 New construction: Indian Institute of Technology, Kanpur, India

Energy efficiency features
EPI = 240 kWh/m2.annum
 Building envelope
Envelope optimization
 Cavity wall with insulation
 Insulated & shaded roof
EPI = 208 kWh/m2.annum
 Double glazed & shaded windows Lighting optimization
 Lighting system
 Efficient fixtures
 Efficient lamps
 Daylight integration
EPI = 168 kWh/m2.annum
HVAC optimization
EPI = 133 kWh/m2.annum
 Heating, ventilation and air
conditioning (HVAC) system
Control systems
 Load calculated with optimized
envelope & lighting system
EPI = 98 kWh/m2.annum
 Efficient chillers
 Efficient condensing system
 Use of geothermal cooling
S8
Energy efficiency retrofit in buildings
 Retrofitting/rehabilitation of government buildings: India

Energy audits conducted in important
government buildings
 President’s Office & Residence Complex
 Prime Minister’s Office
 Government Offices (Power, Railways,
Telecommunications, Transport)
 Medical Institute & Hospital Building
 Airport Terminals

Assessed energy savings potential
 Varying between 25 and 46%
 Payback period: 1 to 4 years

Implementation of recommendations
 Through Energy Service Companies (ESCOs)
President’s Office & Residence Complex
S9
Best practices and exemplary buildings
 Government support for
existing residential homes:
Thailand
 Study the house design
 Provide advice through expert
team for improving energy
efficiency
 Extend financial support up to 30%
of the actual improvement costs
 Support from national energy agency (DEDE) for the construction of energy
efficient new residential homes
 Detailed design of 3 types of individual houses of different sizes and
costs based on detailed study carried out by experts
 Construction permit given by concerned authorities in a short time
S10
Best practices and exemplary buildings
 Low-cost energy efficient housing promotion: Thailand
OPTION A
Land area: 13.00 m. x 16.00 m.; Built-up area: 84 m2; Configuration: 2 bedrooms, 1 bathroom, living room,
dining room, kitchen, parking for 1 car; Estimated cost (2004) 700,000 Baht
11
ING office building in Amsterdam
 One of the pioneer sustainable building
 Features of the building
 Absence of air conditioning system
 Use of massive 18” interior walls to act as insulator and
building flushed with night air
 Building energy consumption one-tenth of its predecessors and
one-fifth of new office building
 Annual energy cost savings of US$2.9 million compared to costs
of additional features of US$700,000 (payback time of only 3
months)
 Productivity gains through lower absenteeism
P12
Role of public authorities
Examples
of implementation in China
• Harbin / Heihe
▫ Rehabilitation of 6 buildings (20 500 m2)
▫ Construction of 20 rural houses
▫ 50% heating energy savings (65% in 2
buildings)
Extremely
cold
• Beijing
▫ Construction of 240 000 m2 of residential &
commercial buildings
Cold
▫ 65% & 75% energy savings for commercial
& residential buildings, respectively
• Shanghai
▫ Construction of 61 000 m2 of residential &
commercial buildings
▫ 65% heating & cooling energy savings
Cold in
winter and
hot in
summer
P13
Heat transfer & comfort in rural houses
Heat
consumption
of rural houses
• Simulated
heat consumption
of a conventional rural house in
Heihe area
P14
Heat transfer & comfort in rural houses
Heat
consumption
of rural of
houses
• Simulated
heat consumption
a
well insulated rural house in
Heihe area:
▫ Most insulated house constructed
with following features
 18 cm EPS insulation in walls
 12 cm EPS insulation in floor
 18 cm EPS + 20 cm wood chips in
the roof above the ceiling
 Triple glazing plastic windows +
well ceiled night times curtains
 Improved air tightness with inlet
pipes for fresh hygienic air
▫ Assumption: the whole house is
maintained at 18°C throughout
winter
▫ Average coal consumption of the
house: 2.75 tons/year
▫ This represents 72% savings in
fuel consumption!
P15
Heat transfer & comfort in rural houses
Heat consumption of rural houses
• Simulated heat consumption of a well insulated rural house
in Heihe area
Heat transfer & comfort in rural houses
Comparison
of heat consumption
• Results of measurements
made on insulated houses in Heihe area:
▫ A well insulated house uses 2.5 times less energy/m2 than the
conventional one;
▫ A very well insulated one uses 4.4 times less energy/m2 than the
conventional one
Heat transfer & comfort in rural houses
Parameters
thermal
comfort
• Parametersof
with
significant
influence on
thermal energy use in winter
▫ Internal air temperature
▫ Inside building envelope temperature
(walls, glazing, roof, floor)
▫ Mean radiant temperature, which is the
temperature effectively felt by occupants
▫ Internal relative air humidity that should
be kept below 60% for better comfort and
for avoiding condensation and moisture
appearance on inner walls;
▫ Velocity of air streams on occupants with
air colder than skin temperature (about
32°C) should be kept below 0.2 m/s;
▫ Temperature gradient in the room should
be kept minimal by preferring radiant
heating systems rather than convective
ones
18
Office building in Melbourne, Australia
 Refurbished with 87% of the building
structure recycled and awarded 6 green
star- office design rating
 Project achievements:
 65% reduction in energy use compared to
use prior to retrofit
 88% reduction in water use compared to
average
 72% reduction in sewer discharge
 54% waste reduction compared to average
 Energy consumption 2009: 69kWh/m²/per
annum
 http://www.ourgreenoffice.com/project%
20pages/key_features.html
Office building Melbourne, Australia
Energy:
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Lighting Controls
Lighting
Building Management System
Mixed mode air-conditioning (natural
ventilation and gas-driven airconditioning units)
Building Envelope Efficiency
BMS Occupancy Control & Car Park
Ventilation
Central Vacuum System
Embedded Generation and Demand
Management
Monitoring & Verification
Solar Arrays
Solar Hot Water
Interface to Security
Lift Upgrade
Water:
• Accredited Low Flow Taps
• Accredited Waterless Urinals
• Dual Flush Toilets
• Electronic Taps
• Grey Water / Rainwater Harvesting
• Sprinkler Water Recovery
• Waste Management
• 3 bin system
Indoor Environment Quality
• Automated Windows and, Natural
Ventilation
• Mixed Mode & Openable Windows
• Weather Station
• Materials & Indoor Air Quality
• Dedicated Tenants Exhaust Riser
Transport
• Introduction of cycle racks and cycle
facilities
• Reduction in number and sizes of car
spaces
• 40 Albert Road is close to major
transport hubs and public transport
Retrofitting prefabricated buildings - Ulaanbaatar
Mongolia
• Approximately 250,000 people (20% of the urban population) live in
prefabricated buildings in Ulaanbaatar.
• Pilot project of one apartment building to determine potential energy savings.
• It was found that up to 40 % of the heating energy can be saved. A potential
60% or more is also possible with consumption-oriented heating tariffs.
Source: D + C journal, GTZ article, accessed from
http://www.inwent.org/ez/articles/168966/index.en.shtml
Source: Thermo-technical rehabilitation of pre-cast panel buildings in Ulaanbaatar, pre-feasibility study, City
Government of Ulaanbaatar, Cities Development Initiative for Asia (CDIA), GTZ, 2009
Scaling up to all of Ulaanbaatar
• The potential savings of scaling this pilot up to all
prefabricated buildings in Ulaanbaatar:
▫ 426 buildings, a total of 2,973,840 m2 floor-space;
▫ Estimated heat energy consumption in 2007:
1,040,844,000 kWh/year.
▫ Estimated heat energy consumption after retrofitting:
297,384,000 kWh/year
▫ Energy saved : 743,460,000 kWh/year
▫ Coal saved: 561'724 tonnes/year or 8320 wagons
▫ CO2 saved: 842'586 tonnes/year
▫ Financial savings: 8,987,576,320 ₮ (USD 7,681,689
(2007) USD 6,454,737 (Mar 2010))
Source: GTZ/UDCP, Energy saving potential through thermo-technical rehabilitation of precast panel
buildings in Ulaanbaatar, Mongolia, 2007
Thank you!!
Kelly Hayden
Energy Security Section
ESCAP
haydenk@un.org
Barriers to energy efficiency in
buildings
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Decentralized nature of the building sector
Lack of interaction
Misplaced incentives
Lack of information
Transaction costs
Deficient design process
Energy prices and market barriers