Growing and potential impacts of climate change, such as flooding in coastal areas, change in weather patterns, and melting of the permafrost have created new challenges for the engineering and construction industry. These challenges involve adaptation in the design and construction of projects to address these impacts, as well as developing ways to reduce and controlling greenhouse gas (GHG) emissions to mitigate climate change.
Engineering has the lead responsibility for determining the technical feasibility and cost parameters to overcome these challenges. Engineering and construction projects are implemented with the help of a set of standard documents that lay out the work process of the projects. They include standard design detail drawings, standard design criteria, standard specifications, design guides and work process flow diagrams. Incorporating in these standard documents materials and processes which assist project engineers to identify and assess climate change related impacts can be a major step in effectively preparing to meet the challenges of climate change mitigation and adaptation.
3. INTRODUCTION
:
New challenges for the construction industry
• Impacts of climate change
• Design to reduce GHG emissions
Engineering has the lead responsibility
• For determining the technical feasibility and cost
Set of standard documents
• Standard design detail drawings, standard design
criteria, standard specifications
• Design guides and work process flow diagrams
4. Climate change & Potential
Impacts:
Climate Change
How Will Climate Change
The Contribution of Buildings to Climate Change
The Impact of Climate Change on Construction
Potential Impacts On Development
5. Climate Change:
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IPCC declared that ‘warming of the climate system is unequivocal’
– Changes in temperatures
– Hot extremes, heat waves and heavy precipitation events
– Tropical cyclones with larger peak wind speeds
– Heavy precipitation associated with ongoing increases of
tropical sea surface temperatures.
– Decreases in snow cover
6. How will Climate Change:
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All parts of the world will experience significant changes
in climate over this century. These changes can be summarised as:
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Hotter, drier summers
Milder, wetter winters
More frequent extreme high temperatures
More frequent extreme winter precipitation
Significant decreases in soil moisture content in the summer
Net Sea level rise and increases in sea surge height
Possible higher wind speeds
7. The Contribution of Buildings:
Today, buildings are responsible for more than 40 percent of
global energy used, and as much as one third of global greenhouse
gas emissions, both in developed and developing countries.
In absolute terms:
•8.6 billion metric tons CO2 eqv in 2004
•15.6 billion metric tons CO2 eqv. by 2030 (expected)
Furthermore, the Buildings and Construction Sector is also
responsible for significant non-CO2 GHG emissions such as
halocarbons (CFCs and HCFCs) and hydro fluorocarbons (HFCs)
due to their applications for cooling, refrigeration, and in the case of
halocarbons, insulation materials.
8. The Impact on Construction:
Climatic factors
Soil Drying
Temperature
Relative Humidity
Precipitation
Impacts
Increase will affect water tables and could affect foundations in
clay soils
Maximum and minimum changes will affect heating, cooling, air
conditioning costs and thermal air movement. Frequency of
cycling through freezing point will affect durability.
Increase will affect condensation and associated damage or
mould growth
Increase and decrease will affect water tables (foundations and
basements); cleaning costs will be increased in winter, with
associated redecoration requirements.
Gales
Increase will affect need for weather tightness, risk of water
ingress, effectiveness of air conditioning, energy use, risk of roof
failures
Radiation
Increase may affect need for solar glare control
Cloud
Increase in winter will increase the need for electric lighting;
reduction in summer may reduce the need for electric lighting for
certain buildings
9. Impacts
Components,
sub-structures and
whole buildings
Air conditioning
Need to upgrade airtightness
Basements
(sub-structure)
Increased risk of heave or subsidence, water ingress,
consequential damage to finishes and stored items
Materials
Plastics life is reduced due to increased radiation Increased
salt spray zone in marine areas will reduce life duration
Roofs
Increased fixing costs and risk of failures due to gales,
wind and Precipitation
Increased cleaning costs due to wind, gales, relative
humidity, precipitation. May alter construction costs and
period owing to wet weather and associated loss of
production.
Whole building
Structure/cladding/ Increased risk of cracking due to different thermal or
renders/Membranes moisture movements
Timber-framed
Construction
Increased risk of failure due to increase in relative
humidity, depending on design
10. OPTIMIZING THE DESIGN PROCESS:
In many respects designing to meet climate change challenges
is sustainable design. A project execution approach integrating the
following concepts for sustainable engineering, procurement and
construction (S-EPC) is directly relevant to designing for climate
change:
•Site master planning and design for ecology
•Process design to conserve water, energy and other natural resources
•Passive design of facilities to save energy in plant and building operations, e.g.
Energy Star® roofs or green (vegetated) roofs; adequate insulation of building
walls, roofs, pipes, ducts and vessels, to minimize fossil-fuelled power
consumption and emissions
•High-efficiency HVAC and electrical systems including high-performance
lighting systems integrated with daylighting and smart controls
•Onsite renewable energy with energy storage for peak use, meeting the power
demand that has been reduced by all of the above concepts, and resulting in
reduced fossil fuel demand / emissions.
•Eco-purchasing and contracting: “greening” the supply chain to minimize
climate change impacts of the supply chain.
11. CONCEPTUAL DESIGN:
The conceptual design phase is when sustainable design,
climate change mitigation and adaptation features can be most easily
incorporated into a project.
During conceptual design, the integrated sustainable design team
evaluates design alternatives. Project facilities, process and mechanical
equipment, and building components or features should be evaluated based on
their sustainability as well as feasibility and cost-effectiveness. The team should
consider the maturity of the technology of the building, facility or process
feature; the capital expenditure (i.e., first cost) required to procure, install, and
implement the facility, building or process feature under consideration.
Consider alternatives to:
•Maximize energy efficiency and minimize GHG emissions:
•Maximize water efficiency:
•Minimize the embodied energy and carbon content of materials:
12. PRELIMINARY DESIGN:
During preliminary design develop the facility energy model to
confirm the design meets the established performance goals; calculate
facility operations GHG emissions and materials embodied carbon
content; develop a facility life-cycle cost estimate; include building
information in the 3-D model. Periodically update these calculations and
verify the project continues to meet the sustainable design performance
goals as design progresses.
The following tasks are included in this design phase:
•Include sustainable engineering concepts in system design descriptions and
facility design descriptions. Right-size systems and facilities using software
models (not conventional rules-of thumb), avoid over-design.
•Identify energy consumption by category, e.g., internal loads from the
processes, building envelope loads (heat losses / gains through walls, roofs,
etc.), ventilation requirements, and others.
13. Contd…
• Identify energy interactions between systems and opportunities for
reductions in energy requirements and cost savings through energy
efficiency measures.
• Develop alternative design solutions to reduce energy loads and evaluate
systems as a whole.
• Iterate these optimization steps and refine the system selection / design to
arrive at the optimized combination of systems for energy efficiency and
emissions reduction.
• Update the energy model, emissions calculations, cost estimate and 3-D
model to reflect the design, as it develops.
Conduct a second review of progress toward meeting energy and
emissions goals on the project, after the design concept is developed. This
review can be concurrent with other required design reviews and is
intended to confirm continued progress toward meeting the established
sustainable design criteria.
14. DETAILED DESIGN &
CONSTRUCTION :
Continue to promote an integrated work process among all
disciplines to assure continued implementation of the established energy
efficiency and emissions reduction goals. Specify low embodied CO2
and energy content materials. Include embodied energy and CO2
evaluation criteria in technical bid evaluations. Specify materials
available locally.
Consider construction waste management options, construction
vehicle options, etc.
Finalize the:
•Energy model
•3-D model with building information
•GHG emissions calculations
•Life-cycle cost estimate
Conduct a third and final review of the design relative to the energy
efficiency and emissions reduction goals.
15. ENERGY EFFICIENCY
MODELS:
THERE ARE DIFFERENT LOGICS in pursuing the energy
efficiency of buildings, ranging from lower to higher technological
approaches. These are models that can be applied to improve energy
efficiency in buildings;
• Low- and zero-energy buildings
• Passive housing de-sign
• Energy-plus buildings
• EcoCities
• Refurbishment aspects
• Commissioning processes.
16. Low Energy Buildings:
The Definition of low-energy building can be divided into two
specific approaches:
The concept of 50% & The concept of 0%
A building constructed using the 50% concept consumes only
one half of the heating energy of a standard building.
The low energy consumption is based on an increased level of
thermal insulation, high performance windows, airtight structural
details and a ventilation heat recovery system.
In USA-Arizona, USA-Grand Canyon (California), Belgium,
Canada, Denmark, Finland, Germany, Italy, Japan, the Netherlands,
Norway, Sweden and Switzerland zero energy buildings were built.
17. Zero Energy Buildings:
Zero-energy buildings(an ultra-low-energy buildings) are buildings
that produce as much energy as they consume over a full year.
Energy can be stored on site, in batteries or thermal storage.
The grid can be used as seasonal storage via net metering, as some
buildings produce more in the summer and use more in the winter, but
when the annual accounting is complete, the total net energy use must
be zero. Buildings that produce a surplus of energy are known as
energy-plus buildings.
The Worldwide Fund for Nature (WWF) zero-energy housing
project in the Netherlands & The Malaysia Energy Centre (Pusat
Tenaga Malaysia) headquarters are zero-energy office (ZEO)
buildings.
18. Passive Houses:
A passive house is a building in which a comfortable interior
climate can be maintained with-out active heating and cooling systems.
The house heats and cools itself, and is therefore ‘passive’.
Characteristics of passive houses
Compact form and good insulation:
U-Factor <=0.15W/(m2K)
Orientation and shade considerations:
Passive use of solar energy
Energy-efficient window glazing and U-Factor <=0.80W/(m2K) {glazing and frames, combined}
frames:
solar heat-gain coefficients around 50%
Building envelope air-tightness:
Air Leakage <=0.61/hour
Passive pre heating of fresh air:
Fresh air supply through underground ducts that exchange
heat with the soil. This preheats fresh air to a temperature
above 5oC, even on cold winter days
Highly efficient heat recovery from Heat recovery rate over 80%
exhaust air:
Hot water supply using regenerative Solar collectors or Heat pumps
energy sources:
Energy-saving household appliances:
Low energy refrigerators, stoves, freezers, lamps, washers,
dryers, etc. are indispensable in a passive house
19. Eco Cities:
In order to render the building energy efficient, the whole
energy chain has to be considered, including the local environmental
conditions, community issues, transportation systems and working and
living structures.
Eco Cities are settlement patterns for sustainable cities, which
were developed in a project supported by the European Union. The
energy chain for buildings in Eco Cities includes the following items:
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Low-energy houses;
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Low-temperature heating systems;
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Low-temperature heat distribution system;
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Use of renewable energy sources whenever possible;
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Heat production as near as possible;
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Electricity production;
20. CONCLUSIO
N to
Designing : meet the challenges of climate change
does not require a completely new design process.
Incorporating sustainable design considerations into the
conventional design process can result in more energy efficient
and lower GHG emitting designs if sustainable design
performance goals are set early in the project development and
regularly monitored to assure the evolving design continues to
support achieving the goals.
And when considered in the context of the overall life-
cycle cost of a project, sustainable design will reduce life-cycle
costs and produce significant benefits for climate change.
21. REFERENCES
:
Dr. R. B. Draper, Dr. P Attanayake (2010),” DESIGNING TO
MEET CLIMATE CHANGE CHALLENGES”, International
Conference on Sustainable Built Environment (ICSBE-2010).
Sylvie Lemmet, (2010), “SUSTAINABLE BUILDINGS AND
CLIMATE INITIATIVE”, Sustainable united Nations.
“BUILDINGS AND CLIMATE CHANGE” - Status, Challenges and
Opportunities by United Nations Environment Programme, 2007.
Gardiner, Theobald (2006), “ADOPTING TO CLIMATE CHANGE
IMPACTS: A good practice guide for sustainable communities”.
Michael J. Holmes, Jacob N. Hacker (2007), “CLIMATE CHANGE,
THERMAL COMFORT AND ENERGY: Meeting the design
challenges of the 21st century”
N.J. Cullen BSc(Hons), “CLIMATE CHANGE –DESIGNING
BUILDINGS WITH A FUTURE”, National Conference 2001
MarkSnow, Deo Prasad (2011), “CLIMATE CHANGE ADAPTION
FOR BUILDING DESIGNERS”, Australian Institute of Architects.