Energy efficiency in buildingsCase 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
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)
50-100 years lifetime!
Materials
Extraction
Site Assembling
Transport Electricity-HVAC
Power plant
Solid waste
Demolition
Operation DemolitionConstructionPre-construction
Slide prepared for ESCAP by Prof. B. Mohanty
Embodied versus operating energy
P4
Manufacturing
Embodied Energy
Operating Energy
1. Indirect 2. Direct
Poor design, less comfort, higher electricity consumption
By combining different techniques, small increases in embodied energy will greatly decrease operating and total energy use
Linkage
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
S5
Best practices and exemplary buildings
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 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
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
Malaysia Energy Centre
New construction: Indian Institute of Technology, Kanpur, India
S7
Best practices and exemplary buildings
Energy efficiency features Building envelope
Cavity wall with insulation Insulated & shaded roof Double glazed & shaded
windows Lighting system
Efficient fixtures Efficient lamps Daylight integration
Heating, ventilation and air conditioning (HVAC) system
Load calculated with optimized envelope & lighting system
Efficient chillers Efficient condensing system Use of geothermal cooling
EPI = 240 kWh/m2.annum
EPI = 208 kWh/m2.annum
EPI = 168 kWh/m2.annum
EPI = 133 kWh/m2.annum
EPI = 98 kWh/m2.annum
Envelope optimization
Lighting optimization
HVAC optimization
Control systems
Retrofitting/rehabilitation of government buildings: India
S8
Energy efficiency retrofit in buildings
President’s Office & Residence Complex
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)
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
S9
Best practices and exemplary buildings
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
Low-cost energy efficient housing promotion: Thailand
S10
Best practices and exemplary buildings
OPTION ALand 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
Role of public authoritiesExamples 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)
•Beijing▫ Construction of 240 000 m2 of residential &
commercial buildings▫ 65% & 75% energy savings for
commercial & residential buildings, respectively
•Shanghai▫ Construction of 61 000 m2 of residential &
commercial buildings▫ 65% heating & cooling energy savings
P12
Extremely cold
Cold
Cold in winter and hot in summer
Heat transfer & comfort in rural housesHeat consumption of rural houses• Simulated heat consumption of a conventional rural house in
Heihe area
P13
Heat transfer & comfort in rural housesHeat consumption of rural houses• Simulated heat consumption of 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!
P14
Heat transfer & comfort in rural housesHeat consumption of rural houses
• Simulated heat consumption of a well insulated rural house in Heihe area
P15
Heat transfer & comfort in rural housesComparison 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 housesParameters of thermal comfort• Parameters 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, AustraliaEnergy:• Lighting Controls• Lighting• Building Management System• Mixed mode air-conditioning
(natural ventilation and gas-driven air-conditioning 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 systemIndoor Environment Quality• Automated Windows and, Natural Ventilation • Mixed Mode & Openable Windows• Weather Station• Materials & Indoor Air Quality• Dedicated Tenants Exhaust RiserTransport• 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
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
Retrofitting prefabricated buildings - Ulaanbaatar
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