Energy efficient in buildings

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					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

                                                          Power plant
                           Site Assembling

         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

          Embodied versus operating energy


                        1. Indirect                   2. Direct
                        Embodied                     Operating
                         Energy                       Energy

                 Poor design, less comfort, higher electricity consumption

        By combining different techniques, small increases in embodied energy
                will greatly decrease operating and total energy use

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

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
Malaysia Energy Centre                            Energy management system

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             EPI = 168 kWh/m2.annum
          Efficient lamps                     HVAC optimization
          Daylight integration
      Heating, ventilation and air       EPI = 133 kWh/m2.annum
       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

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
                                                  President’s Office & Residence Complex
   Implementation of recommendations
      Through Energy Service Companies (ESCOs)

Best practices and exemplary buildings
                                     Government support for
                                      existing residential homes:
                                        Study the house design
                                        Provide advice through expert
                                         team for improving energy
                                        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

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

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
    Productivity gains through lower absenteeism

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
• Beijing
   ▫ Construction of 240 000 m2 of residential &
     commercial buildings
   ▫ 65% & 75% energy savings for commercial
     & residential buildings, respectively
                                                          Cold in
• Shanghai                                                winter and
                                                          hot in
   ▫ Construction of 61 000 m2 of residential &           summer
     commercial buildings
   ▫ 65% heating & cooling energy savings

Heat transfer & comfort in rural houses
Heat consumption of rural houses
 • Simulated heat consumption of a conventional rural house in
   Heihe area

Heat transfer & comfort in rural houses
 • Simulated heat consumption houses
Heat consumption of rural 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
   ▫ Average coal consumption of the
     house: 2.75 tons/year
   ▫ This represents 72% savings in
     fuel consumption!

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 houses in Heihe area:
 • Results of measurements made on insulated
   ▫ 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 of thermal comfort on
 • Parameters with significant influence
   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

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
   72% reduction in sewer discharge
   54% waste reduction compared to average
 Energy consumption 2009: 69kWh/m²/per
    Office building Melbourne, Australia
Energy:                                    Water:
                                           • Accredited Low Flow Taps
•   Lighting Controls                      • Accredited Waterless Urinals
•   Lighting                               • Dual Flush Toilets
•   Building Management System             • Electronic Taps
•   Mixed mode air-conditioning (natural   • Grey Water / Rainwater Harvesting
                                           • Sprinkler Water Recovery
    ventilation and gas-driven air-
                                           • Waste Management
    conditioning units)
                                           • 3 bin system
•   Building Envelope Efficiency           Indoor Environment Quality
•   BMS Occupancy Control & Car Park       • Automated Windows and, Natural
    Ventilation                              Ventilation
•   Central Vacuum System                  • Mixed Mode & Openable Windows
                                           • Weather Station
•   Embedded Generation and Demand
                                           • Materials & Indoor Air Quality
    Management                             • Dedicated Tenants Exhaust Riser
•   Monitoring & Verification              Transport
•   Solar Arrays                           • Introduction of cycle racks and cycle
•   Solar Hot Water                          facilities
                                           • Reduction in number and sizes of car
•   Interface to Security                    spaces
    Lift Upgrade                           • 40 Albert Road is close to major
                                             transport hubs and public transport
Retrofitting prefabricated buildings - Ulaanbaatar


• 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
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
Barriers to energy efficiency in
•   Decentralized nature of the building sector
•   Lack of interaction
•   Misplaced incentives
•   Lack of information
•   Transaction costs
•   Deficient design process
•   Energy prices and market barriers