Energy efficiency in buildings

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

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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

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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

Thank you!! Kelly HaydenEnergy Security [email protected]

Barriers to energy efficiency in buildings•Decentralized nature of the building

sector•Lack of interaction•Misplaced incentives•Lack of information•Transaction costs•Deficient design process•Energy prices and market barriers