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Energy efficiency in buildings

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. Pre-construction. Construction.

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Energy efficiency in buildings

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  1. Energy efficiency in buildings Case studies from around the world Case studies and most slides prepared for ESCAP by Prof. B. Mohanty

  2. Around 50% of all electricity is used in buildings Source: OECD/IEA, 2008, Energy Technology Perspectives 2008

  3. Pre-construction Construction Operation Demolition 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) Demolition Power plant Site Assembling Materials Electricity-HVAC Solid waste Extraction Transport 50-100 years lifetime! Slide prepared for ESCAP by Prof. B. Mohanty

  4. Embodied versus operating energy Manufacturing 1. Indirect 2. Direct Embodied Energy Operating Energy Linkage Poor design, less comfort, higherelectricity consumption By combining different techniques, small increases in embodied energy will greatly decrease operating and total energy use

  5. 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 • 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

  7. EPI = 240 kWh/m2.annum Envelope optimization EPI = 208 kWh/m2.annum Lighting optimization EPI = 168 kWh/m2.annum HVAC optimization EPI = 133 kWh/m2.annum Control systems EPI = 98 kWh/m2.annum 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 • New construction: Indian Institute of Technology, Kanpur, India

  8. Energy efficiency retrofit in buildings • 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) • Retrofitting/rehabilitation of government buildings: India President’s Office & Residence Complex

  9. 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

  10. 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

  12. 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 Extremely cold Cold Cold in winter and hot in summer

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

  14. Heat transfer & comfort in rural housesHeat consumption of rural houses • Simulated heat consumption of a well insulated rural house in Heihearea: • 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!

  15. Heat transfer & comfort in rural housesHeat consumption of rural houses • Simulated heat consumption of a well insulated rural house in Heihe area

  16. Heat transfer & comfort in rural housesComparison of heat consumption • Results of measurements made on insulated houses in Heihearea: • 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

  17. 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

  19. Office building Melbourne, Australia Energy: • 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 SecurityLift 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

  20. 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

  21. 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

  22. 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

  23. Thank you!! Kelly Hayden Energy Security Section ESCAP haydenk@un.org

  24. 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

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