DDepartment of Civil Engineering Green Building Technologies

UNIT-1

GREEN BUILDINGS

Definition: A Green building or sustainable building is a structure which is designed,

constructed, operated, or reused in an ecological and energy-efficient manner. A Green
Building is one which uses less water, optimises energy efficiency, conserves natural
resources, generates less water and provides healthier spaces for occupants as compared to a
conventional building.

Green building is the only answer through creating healthier and more resource-efficient
models of construction, renovation, operation, and maintenance. Green Architecture and
sustainable buildings are considered a modern trend in architectural thinking which
manipulates the relationship between the building and the environment.

Generally, office buildings are one of the highest types of buildings in energy consumption
compared to other building types. so it’s very important for an architect to implement specific
strategies in order to decrease energy consumption, especially in this type of building, by
using renewable energy sources such as solar energy, wind energy, and other sources which
contribute to electric energy rationalization.

Green Building refers to a structure and building process that is environmentally responsible
and resource-efficient throughout a building’s life cycle from sitting to design, construction,
operation, maintenance, renovation and demolition. This requires close cooperation of the
design team, the architects, the engineers and the client at all project stages. The Green
Building practice expands and complements the classical building design concerns of
economy, utility, durability and comfort.
The concept of Green building integrates a variety of strategies during the period of Design,
Construction, Maintenance, and Operation of buildings. Construction is an element of
civilization which is increasing continuously and thereby requires lots of natural or manmade
materials to fulfill the demand. Manufacturing of construction materials like Cement,
Conventional brick, steel, etc. These materials produce a large amount of CO2 and other
greenhouse gases which are hazardous or toxic in nature and cause environmental and health-
related problems. So it is today’s demand to acquire good construction practice and energy
efficient material which helps in less production of greenhouse gases and save energy.

Generally there are 4 elements of green building and that shows the main points required to
be considered while designing any building.
1. Smart Design
2. Energy efficiency
3. Eco Materials
4. Water Conservation

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Typical Features of Green Buildings

A green building includes environmental considerations in each stage of the building
construction and focuses on the design, construction, operation, and maintenance phases.

Green buildings typically incorporate superior air quality, abundant natural light, access to
views, and noise control which benefits building occupants, making these buildings better
places to work or live.

some of the most highlighted features of Green Buildings are

1. Air tightness and vapour barrier in building walls and surfaces

2. Waste reduction
3. Enthalpy recovery of exhaust air
4. Low solar heat gain coefficient of glass
5. Daylight-controlled lighting systems
6. Occupancy sensors
7. Water-efficient fittings
8. Rain-water harvesting
9. Materials recovery facility (MRF)
10. Vegetation
11. Site sustainability
12. Geothermal Heating and Cooling
13. HEPA (High-efficiency particulate arrestance)
14. CO2 Controlling ventilators
15. VSD(Variable Speed Drives)
16. Use of solar panels
17. Solar thermal collectors
18. Greywater/Blackwater Recycling
19. LED
20.Wind Turbines

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1.Air tightness and vapour barrier in building walls and surfaces

Walls that are able to keep out moisture and humidity from outside will make the building
naturally cooler. Because of this, air-conditioning systems will not have to work so hard to
cool down the building and thus lowers electricity costs.

2.Waste Reduction

Pollution control measures adopted and implemented on the project sites during construction
activities, Green buildings aim to reduce the amount of material being sent to landfills during
construction.

3.Enthalpy recovery of exhaust air

A device called an enthalpy wheel recovers cooled air from the inside and uses the coolness
of this “spent” air to cool fresh air from outside.

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4.Low solar heat gain coefficient of glass

Solar heat gain coefficient (SHGC) is the amount of solar radiation that enters through glass
and is released as beat inside a building. The lower the SHGC, the less solar heat it transmits,
and the cooler the building. This also lowers electricity costs because air-conditioning
systems don’t have to do all the work.

5.Daylight-controlled lighting systems

This type of lighting system has sensors that can detect daylight. During the day, the sensor
switches off the lights since there is enough light from the sun. When the sun sets, the system
will switch the lights on. This way, the use of artificial lighting during the daytime is reduced.

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6.Occupancy sensors

This lighting system only turns on when it senses people in the room. This technology can
also be found in escalators that activate only when there are people riding on them.
The process also dehumidifies the air from outside. This is a cost-efficient way to improve
indoor air quality and lessen energy consumed by air-conditioning systems.

7.Water-efficient fittings

The latest faucets and flush mechanisms use less water to do the same thing.

8. Rain-water Harvesting

A structure catches rainwater and then stores it in big containers. The water can then be used
to water plants, flush toilets, or supply cooling towers.

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9. Materials recovery facility (MRF)

An MRF is where the building’s garbage is segregated into biodegradable, recyclable, non-
recyclable, and special or hazardous waste. Biodegradable waste can be composted and used
as fertilizer for the building’s plants.

10. Vegetation

A significant portion of the building’s unpaved area is devoted to vegetation. This helps
reduce the heat urban island effect-when concrete surfaces so common in urban areas absorb
heat from the sun and radiate it to the surroundings. Plants also help absorb some rainwater
which would otherwise go to sewers and drainage, later on contributing to flooding.

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11.Site Sustainability

The building’s design, construction, and operation practices should have minimum impact on
ecosystems and water resources.

12. Geothermal Heating and Cooling-

The underground is an excellent heat sink in summer and an excellent heat source in winter.
Geothermal heat pumps take advantage of this providing heating and cooling for buildings

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with a lower kWh consumption than other methods. Indoor heating and cooling are provided
normally with hydronic piping, air-handling units, and air ducts.

13. HEPA (High-efficiency particulate arrestance)

HEPA stands for high-efficiency particulate arrestance. HEPA filters are among the best
available, capturing 99.97% of particles with a size of 0.3 microns or more. These filters
remove many pollutants and allergens from the air, improving indoor air quality.

14. CO2 Controlling Ventilators

Since human metabolism produces carbon dioxide, occupancy can be correlated with the
CO2 concentration in the air. Ventilation can be controlled with CO 2 sensors, reducing
airflow in proportion to occupancy to achieve energy savings.
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15. VSD(Variable Speed Drives)

Variable speed drives(VSD) are devices that modify the voltage and frequency supplied to a
motor, allowing it to operate below-rated rpm. VSDs are very useful in motors that drive fans
and pumps since these devices are often subject to part-load conditions. They are also known
as variable frequency drives (VFD).

16. Use of solar panels

Solar panels are among the most promising building upgrades if you have plenty of rooftop
areas available. They normally come with a 10-year warranty for manufacturing defects and a
25-year warranty for energy generation, in addition to having simple maintenance needs.

The payback period of solar panels only represents a small fraction of their service life.
Simple maintenance. The main requirement is keeping panel surfaces clean and free
of shadows. May be eligible for incentives from the government or utility companies.

17. Solar thermal collectors

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Solar radiation is used directly for domestic hot water instead of electricity generation. With
this building upgrade, you can rely less on your gas-fired water heater. There may be a slight
pumping cost in taller buildings since water has to reach the rooftop, but it is much less than
the ongoing cost of a water heater. However, Solar thermal collectors also harness sunlight.

18. Greywater/Blackwater Recycling-

The concepts of greywater and blackwater are used to describe water that has already been
used in plumbing fixtures. Blackwater includes water from all fixtures, while greywater
excludes the water discharged from toilets.

Although greywater is polluted with cleaning agents and grease, it can be collected and
reused for purposes such as flushing toilets or outdoor watering. Blackwater can also
be recycled for some purposes, but it requires special treatment.

19. LED

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LED uses over 30% less power consumption than fluorescent, over 50% less than HID, and
over 80% less than incandescent. LED also Reduced the cooling load for AC and
refrigeration equipment. LEDs have a long service life and almost no maintenance is
required.

20. Wind Turbines

A single wind turbine results in a lower cost per kilowatt. Electricity generation is enhanced
with a taller tower since airflow is more stable as height increases. Smaller turbines are closer
to the ground and susceptible to the turbulence caused by trees and constructions.

Benefits of Green Buildings:

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Following are the benefits of Green Building:

1. Reduction of natural resource consumption

2. Reduction of operating costs
3. Health, comfort and safety for all residents
4. Energy optimization and reduction of energy consumption
5. Increased productivity of the occupants
6. Better indoor air quality (IAQ has a tremendous impact on human health)
7. Green Building encourages companies to benefit from the Green corporate image and
to leave a very positive impression on customers, employees, business partners and
shareholders.

Sustainable Site Selection:

The Site on which we build can influence each and every aspect of the building we choose. In
this article, you can learn about various aspects to consider in site selection.

The primary goals for green buildings in selecting a site are

1. Protecting sensitive sites

2. Preserving undeveloped sites
3. Restoring and Reusing previously developed sites
4. Reducing impact on flora and fauna
5. Promoting connection to the community
6. Minimizing transportation impacts both the environment and energy use.

1. Site Selection Criteria

 The site selection and site plan must fulfill the regulations and guidelines of
UDPFI(Urban Development Plan Formulation and Implementation) , Eco-sensitive
zone regulations, Coastal zone regulations, and any other specific local bye-laws.
 Minimizing land disturbances by selecting previously disturbed lands; sites that are
close to public transportation, community and work centers, and services such as
pumping water and transporting electricity.
 Minimize long-term impacts on the community.
 Creating neighbourhoods with compactness, connectivity, and walkable streets.
 Climate zones (cold /hot/mixed) and Local Hydrology will have an impact on
building design. The same type of building will be designed in a different way
depending on outdoor temperature, outdoor humidity, and solar radiation.

The design varies in various aspects such as:

oWall materials and assembly

oSize and orientation of windows
oHeating system selection
oMethods for controlling moisture
oType of vegetation available for landscaping.
 Encouraging using less polluting modes of transportation.

2. Protection of Sensitive sites – Site Selection

 Site selection and Protect sensitive sites. These include

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o Prime farmland
o Parkland
o Flood hazard areas
o Habitat for endangered or threatened species
o Primary dunes
o Old-growth forests
o Wetlands and other water bodies (50′-100′ buffer space)
o Conservation areas

 Not developing or undergoing any construction activities within these sites and also
including buffer zones surrounding them.

3. Preservation and Restoration

Green Field Brown field

1. Greenfields are defined as previously undeveloped sites.

2. Brownfields are abandoned industrial and commercial sites that have perceived levels
of contamination.
3. Greyfields are previously developed sites that are not contaminated and have a visible
development and infrastructure
4. Restoring and Reusing Brownfields to prevent/limit the development of Greenfields.
5. Developing Greyfield and promoting urban density

4. Protection of Natural Features

1. Minimize Site disturbance.

2. Protecting the Site’s soil conditions.
o Retaining soils in place.
o Stockpiling and reusing soils.
o Restoring soils during construction.
o Revegetation of disturbed soils.
o Measures to prevent soil runoff during construction.
3. Protection of vegetation present on site.

5. Heat Island Reduction

The heat Islands are generated by the raised levels of temperatures from hardscapes and
buildings, particularly in urban areas. It refers to the absorption and retention of incoming
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solar radiation by the buildings and hard pavements surrounding them. When this heat is
released into the atmosphere, heat islands are formed having higher temperatures in urban
areas, compared to rural areas.

Effects of Higher Temperatures/heat Islands:

1. Increased energy consumption for cooling during summers.

2. Elevate emissions of air pollutants and greenhouse gases.
3. Contribute to heat exhaustion.
4. Heat-related Mortality.
5. Stressing aquatic ecosystems due to raised temperatures of water in streams, lakes and
ponds, rivers, etc.\

Ways to Reduce the Heat Island Effect:

1. Using light-colored roofing having high solar reflectance.

2. Installing green roofs/Vegetated roofs.
3. Including pavement with non-heat-absorbing materials.
4. Planting trees
5. Providing landscapes
6. Shade Parking surfaces.

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6. Site Waste Management

Manage the waste generated during site construction. It includes:

1. Debris such as
o Rocks
o Soil
o Vegetation
2. Any other hazardous materials present

Strategies Include

1. Prevent debris from moving to landfills.

2. Restrict debris transported to sensitive sites such as wetlands.
3. Reusing materials onsite itself.
4. Recycling debris offsite.

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5.

7. Greener forms of Transportation

One of the factors in the site selection process is transportation, proximity, and other
facilities.

1. Proximity to public transportation.

2. Onsite Traffic Signs.
3. Providing facilities of transportation that emit fewer carbon emissions.
o Installing Bicycle racks.
o Facilities for storing and covering bicycles.
o Providing pedestrian paths.
o Sidewalks for walking and biking.
4. Vehicles serving Carpools.
5. Encouraging Electric vehicles and providing electric charging stations.

8. Minimizing Light Pollution

Light pollution is the presence of artificial light in the outdoor environment.

Impacts of Light Pollution:

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1. Disrupts the habitat of nocturnal wildlife.

2. Interferes with normal plant growth cycles.
3. Conceal the night sky; interferes with the ability to view the night sky, stars, and
planets.
4. Causes light trespass – Spill of light into neighbouring properties.
5. Safety Hazard – Produces glare while driving.
6. Assists Intruders – Increase security risks.
7. Wastes energy – impacts environmental and economic concerns.

Strategies to Reduce Light Pollution:

1. Select light fixtures that minimize spillage, and focus light downward rather than
upward.
2. Providing accent lighting for pathways instead of higher pole-mounted lighting.
3. Eliminating Uplighting.
4. Installing fixtures downwards.
5. Locating outdoor amenities close to the main building.
6. Motion sensors and time schedules keep exterior lights on most of the time.
7. Eliminating exterior lighting wherever possible.
8. Reducing lighting near windows.

9. Site Strategies and Energy Use in Site Selection

1. A building on an exposed hilltop utilizes more energy than a building surrounded by

trees or adjacent buildings.
2. Trees, structures, fencing, and other forms of shielding help reduce wind velocity
downwind of the barriers.
3. Site planning not only refers to landscaping and natural features, but also exterior
equipment such as air-conditioning condensers, cooling towers, and pad-mounted
transformers.
o Unlike buildings, these equipment’s operate more efficiently when not
blocked by vegetation or structures.
4. Energy use rises by 20% or more by various risks such as-
o Air blockage by vegetation or other obstructions.

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oContamination of heat exchangers by dust or pollen

oRecirculation of exhausted air.
5. Locating an outdoor unit in an enclosed or partially enclosed location will cause air
recirculation and its high energy use.

Ways to reduce Increased Energy Use :

1. Maintaining clearance between the units and buildings or vegetation.

2. Locating units where outgoing air does not recirculate back into the units.

10. Storm and Site Water Conservation

1. One of the important goals of green projects is to mitigate the negative environmental
effects of stormwater runoff and reduce the use of outdoor use of potable water on the
site.
2. Impervious surfaces, buildings, and conventional storm drainage systems prevent
rainwater from percolating into the soil.
3. Surface runoff (also known as overland flow) is the flow of water occurring on the
ground surface when excess rainwater, stormwater, meltwater, or other sources, can
no longer sufficiently rapidly infiltrate the soil. (Wikipedia)

Effects of Storm Water Runoff:

1. Soil erosion
2. Habitat damage
3. Flooding
4. Water Pollution
5. Groundwater Aquifer depletion
6. Physical and chemical depletion of water resources.
7. Transfers surface contaminants along the same path.

Strategies to Reduce Storm Water Runoff:

Quantity of Storm Water Runoff:

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1. Reducing hardscapes for parking.

2. Minimizing on-site parking by encouraging public and non-motor vehicle
transportation.
3. Providing on-site percolation facilities.
4. Replacing Impervious surfaces with permeable methods such as
o Pervious pavers,
o Porous asphalt,
o Pervious concrete
o Vegetated Landscapes
5. Rainwater harvesting methods on site.
6. Reuse of stormwater for landscapes and flushing toilets.

Quality of Storm Water Runoff:

Advantages:

1. Improved on-site water quality.

2. Improves water quality in downstream rivers and lakes, etc.
o Thereby benefiting flora and fauna

Strategies to improve Quality of Storm Water Runoff

1. Proper management of water quantity and its velocity.

o Reduces containments, such as pesticides, biological waste, garbage, and
sediments.
2. Integrate pest management to minimize the use of pesticides.
3. Minimize on-site vehicles and contaminants to them such as oil, grease, dirt, etc.,
carried by tires.
4. Reduce onsite sources of pollutants – including pesticides, fertilizers, animal waste,
finishes for outdoor structures, etc.
5. Minimize artificial landscaping that requires chemicals.

11. Transported Water

Water is supplied by a municipal water system or well water that is sourced from an
underground aquifer and treated on-site.

Impacts of Using Transported Water:

1. Depletion of Potable Water Resources.

2. Use of water treatment chemicals.
3. Energy use and Power requirements for pumps.
4. Excess and unnecessary use of water increases surface runoff.

Strategies to Reduce Using Transported Water:

1. Employing water Efficiency measures.

2. Using non-potable water wherever possible such as for landscaping, flushing, etc.
3. Landscaping with native plant species that require fewer water resources.
4. Installing efficient irrigation methods such as Drip irrigation.
5. Selecting smaller fountains with fewer surface areas and with low flow rates.
6. Metering of water use helps to monitor the usage of water.
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12. Other Site Issues

Trees and vegetation, which are helpful for shading and protection from the energy effects of
the Sun, can also adversely contribute to humidity and other environmental problems if
located adjacent to buildings.

Trees can also threaten a building’s structure with their roots and branches.

Leaves and small branches can protrude into the windows.

Strategies to overcome the above problems:

1. Providing a buffer zone between the building and trees/vegetation.

2. Promote indoor environmental quality by protecting buildings from dirt and moisture.
o Installing walk-off mats at entrances.
o Textured paving materials instead of gravel.
3. Proper selection of landscaping materials and plants.

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