Green Buildings - innovative green technologies and case studies

Notes on ARC 306 GREEN BUILDINGS : Unit 5
Compiled by CT.Lakshmanan B.Arch., M.C.P. Page 1
UNIT-5 INNOVATIVE GREEN TECHNOLOGIES AND CASE STUDIES 9
Innovative uses of solar energy : BIPV, Solar Forest, Solar powered street elements,- Innovative materials:
Phase changing materials, Light sensitive glass, Self cleansing glass- Integrated Use of Landscape :
Vertical Landscape, Green Wall, Green Roof. Case studies on Green buildings : CII building,Hyderabad,
Gurgaon Development Centre-Wipro Ltd. Gurgaon; Technopolis, Kolkata; Grundfos Pumps India Pvt Ltd,
Chennai; Olympia Technology Park, Chennai.
INNOVATIVE USES OF SOLAR ENERGY
One of the most promising renewable energy technologies is photovoltaics. Photovoltaics (PV) is a truly
elegant means of producing electricity on site, directly from the sun, without concern for energy supply or
environmental harm. These solid-state devices simply make electricity out of sunlight, silently with no
maintenance, no pollution, and no depletion of materials.
A Building Integrated Photovoltaics (BIPV) system consists of integrating photovoltaics modules into the
building envelope, such as the roof or the façade. By simultaneously serving as building envelope material
and power generator, BIPV systems can provide savings in materials and electricity costs, reduce use of
fossil fuels and emission of ozone depleting gases, and add architectural interest to the building.
A complete BIPV system includes:
 the PV modules (which might be thin-film or crystalline, transparent, semi-transparent, or opaque);
 a charge controller, to regulate the power into and out of the battery storage bank (in stand-alone
systems);
 a power storage system, generally comprised of the utility grid in utility-interactive systems or, a
number of batteries in stand-alone systems;
 power conversion equipment including an inverter to convert the PV modules' DC output to AC
compatible with the utility grid;
 backup power supplies such as diesel generators (optional-typically employed in stand-alone systems);
and
 appropriate support and mounting hardware, wiring, and safety disconnects
BIPV system diagram

BIPV systems can either be interfaced with the available utility grid or they may be designed as stand-
alone, off-grid systems. The benefits of power production at the point of use include savings to the utility in
the losses associated with transmission and distribution (known as 'grid support'), and savings to the
consumer through lower electric bills because of peak saving (matching peak production with periods of
peak demand). Moreover, buildings that produce power using renewable energy sources reduce the
demands on traditional utility generators, often reducing the overall emissions of climate-change gasses.
Design of a Building Integrated Photovoltaics (BIPV) System
BIPV systems should be approached to where energy conscious design techniques have been employed,
and equipment and systems have been carefully selected and specified. They should be viewed in terms of
life-cycle cost, and not just initial cost because the overall cost may be reduced by the avoided costs of the
building materials and labor they replace. Design considerations for BIPV systems must include the
building's use and electrical loads, its location and orientation, the appropriate building and safety codes,
and the relevant utility issues and costs.
Steps in designing a BIPV system include:
Carefully consider the application of energy-conscious design practices and/or energy-efficiency measures
to reduce the energy requirements of the building. This will enhance comfort and save money while also
enabling a given BIPV system to provide a greater percentage contribution to the load.
Choose Between a Utility-Interactive PV System and a Stand-alone PV System:
The vast majority of BIPV systems will be tied to a utility grid, using the grid as storage and backup. The
systems should be sized to meet the goals of the owner—typically defined by budget or space constraints;
and, the inverter must be chosen with an understanding of the requirements of the utility.
For those 'stand-alone' systems powered by PV alone, the system, including storage, must be sized to
meet the peak demand/lowest power production projections of the building. To avoid over sizing the
PV/battery system for unusual or occasional peak loads, a backup generator is often used. This kind of
system is sometimes referred to as a "PV-genset hybrid."
Shift the Peak: If the peak building loads do not match the peak power output of the PV array, it may be
economically appropriate to incorporate batteries into certain grid-tied systems to offset the most expensive
power demand periods. This system could also act as an uninterruptible power system (UPS).
Provide Adequate Ventilation: PV conversion efficiencies are reduced by elevated operating
temperatures. This is truer with crystalline silicon PV cells than amorphous silicon thin-films. To improve
conversion efficiency, allow appropriate ventilation behind the modules to dissipate heat.
Evaluate Using Hybrid PV-Solar Thermal Systems: As an option to optimize system efficiency, a
designer may choose to capture and utilize the solar thermal resource developed through the heating of the
modules. This can be attractive in cold climates for the pre-heating of incoming ventilation make-up air.
Consider Integrating Daylighting and Photovoltaic Collection: Using semi-transparent thin-film
modules, or crystalline modules with custom-spaced cells between two layers of glass, designers may use
PV to create unique daylighting features in façade, roofing, or skylight PV systems. The BIPV elements can
also help to reduce unwanted cooling load and glare associated with large expanses of architectural
glazing.

Incorporate PV Modules into Shading Devices: PV arrays conceived as "eyebrows" or awnings over
view glass areas of a building can provide appropriate passive solar shading. When sunshades are
considered as part of an integrated design approach, chiller capacity can often be smaller and perimeter
cooling distribution reduced or even eliminated.
Design for the Local Climate and Environment: Designers should understand the impacts of the climate
and environment on the array output. Cold, clear days will increase power production, while hot, overcast
days will reduce array output;
 Surfaces reflecting light onto the array (e.g., snow) will increase the array output;
 Arrays must be designed for potential snow- and wind-loading conditions;
 Properly angled arrays will shed snow loads relatively quickly; and,
 Arrays in dry, dusty environments or environments with heavy industrial or traffic (auto, airline) pollution
will require washing to limit efficiency losses.
Address Site Planning and Orientation Issues: Early in the design phase, ensure that your solar array
will receive maximum exposure to the sun and will not be shaded by site obstructions such as nearby
buildings or trees. It is particularly important that the system be completely unshaded during the peak solar
collection period consisting of three hours on either side of solar noon. The impact of shading on a PV array
has a much greater influence on the electrical harvest than the footprint of the shadow.
Consider Array Orientation: Different array orientation can have a significant impact on the annual energy
output of a system, with tilted arrays generating 50%-70% more electricity than a vertical façade.
Reduce Building Envelope and Other On-site Loads: Minimize the loads experienced by the BIPV
system. Employ daylighting, energy-efficient motors, and other peak reduction strategies whenever
possible.
Professionals: The use of BIPV is relatively new. Ensure that the design, installation, and maintenance
professionals involved with the project are properly trained, licensed, certified, and experienced in PV
systems work.
In addition, BIPV systems can be designed to blend with traditional building materials and designs, or they
may be used to create a high-technology, future-oriented appearance. Semi-transparent arrays of spaced
crystalline cells can provide diffuse, interior natural lighting. High profile systems can also signal a desire on
the part of the owner to provide an environmentally conscious work environment.
APPLICATION
 Photovoltaics may be integrated into many different assemblies within a building envelope:
 Solar cells can be incorporated into the façade of a building, complementing or replacing traditional
view or spandrel glass. Often, these installations are vertical, reducing access to available solar
resources, but the large surface area of buildings can help compensate for the reduced power.
 Photovoltaics may be incorporated into awnings and saw-tooth designs on a building façade. These
increase access to direct sunlight while providing additional architectural benefits such as passive
shading.
 The use of PV in roofing systems can provide a direct replacement for batten and seam metal roofing
and traditional 3-tab asphalt shingles.
 Using PV for skylight systems can be both an economical use of PV and an exciting design feature.

SOLAR FOREST
A solar forest is a design solution for charging electric vehicles and generating solar energy. This forest
offers shade, provides free EV charging and generates solar energy while simultaneously improving the
appearance of the urban landscape. The trees here have photovoltaic leaves, responsible for collection of
solar power. Each of their trunks has a power outlet to charge an electric vehicle.
Imagine a parking lot that keeps your car cool and charges it while you do whatever you need to do after
parking your car. That’s what the new solar forest designed by designer Neville Mars aims to
achieve. Electric-powered automobiles are a great way of reducing pollution levels but the main hurdle in
the way of them becoming mainstream vehicles is long duration of time they need to recharge. Even to
cover small distance you need to recharge your vehicle for hours. One solution is to speed up the
recharging process, and another is recharging the cars while they stand unused, like in a parking lot.
Sometimes vehicles are left in the parking place for hours while people take care of their chores or work in
their offices. This is the perfect time to charge the vehicles. The trees of the solar forest are made of
photovoltaic leaves mounted upon poles that are like giant power strips for electric vehicles. You can simply
plug in your vehicle to charge it. To increase efficiency the solar panels adjust themselves according to the
position of the sun. The vehicles also remain cool under their shade.
Just like any other new innovation there are naysayers for this project too, like, there is not going to be
enough sun for every tree, or it is going to be very costly to build such panels, and, it will be very difficult to
take your vehicles in (as it happens in the natural forest) and then take them out, but the basic idea is the
thought that goes into such projects. We are sure to find new solutions as more and more people pitch in
instead of just pointing at things that cannot be achieved.

SOLAR AND WATER-POWERED STREET LIGHTS Take a Cue from the Mango Leaf
Designer Adam Mikloski has come up with a beautiful design for solar powered street lights in India.
Mimicking the structure of a seedling and the shape of mango leaves, the concept design captures not just
sunlight but also rain to power the lamps.
The tops of the leaves have solar cells for sunny days. Meanwhile when it rains, the shape of the "leaves"
funnels water to a drain into the post, where a water turbine can gather energy from the moving water.
The designer writes:
[In] India, due to monsoon climate there is a high fall, which can be perfectly utilized...The number
of sunny hours after the rainy season is high. Recycling the power of the sun and rain constitutes
the basis of my concept. To define the shape, I used leaves and shoots of plants. Leaves are

extremely important for drainage. I considered the shape of mango leaves favorable as regards
functionality, shape, and cultural history. The top of the leaf is appropriate for installing solar cells
and for collecting water, while the stalk can divert and recycle this amount of rain. LEDs are
operated by rechargeable batteries.
One question is what happens to the water once it cycles through the post. These lamps will be less
appealing if they have to be part of a more elaborate drainage system under water. However, perhaps it is
enough to have a hole at the base of the post for the water to exit. The LED bulbs are a good choice for
minimizing how much energy the lamps consume, and the rechargeable batteries would be placed in the
post.
Over all, the concept design is a beautiful and elegant use of biomimicry, as well as an interesting and
practical use of both solar and water power to light up a street. Maximizing two natural elements rather than
just one to power the lights is a great way to make sure a design is a good fit for an area with varying
weather, and will work no matter what the conditions.
PHASE-CHANGE MATERIAL
Anyone with thick brick or stone walls has probably noticed that their home takes a long time to heat or cool
during the day. This is because for years architects have employed high mass materials, which slow the
flow of temperature, as a means to build passive, eco-friendly buildings. While these materials work well at
regulating temperature fluctuations, they can be expensive, require additional structure and eat up building
square footage. Thankfully, scientists have been working hard on developing the same technology, but on
a microscopic level, in the form of phase change materials.
The basic idea of passive buildings and thermal mass, is building materials with a high mass (water, stone
or concrete) collect and store heat throughout the day, and then slowly release it as the temperature drops.
Ideally this design technique is used in climates who have extreme temperature fluctuations from day to
night, or season to season. The thermal mass aides in a building's efficiency, reduces the need for heating
and cooling equipment — and is done so without any moving parts.

Phase change materials (PCM) provide thermal mass, but on a much smaller scale. PCMs work by melting
and solidifying at a specific temperature — heat is absorbed at the solid state, and when the material
reaches a predetermined temperature, it changes to a liquid and releases the stored energy (heat). When
the temperature falls below a predetermined degree, the PCM re-solidifys and the process repeats. The
most common PCMs come in the form of paraffin, fatty acids and salt hydrates, each with their own
advantages and disadvantages. Most PCMs must be encapsulated to be stored and prevent evaporation
and absorption.
How do they work?
When heat is applied to a substance, the energy transfers in one of two ways. The first is that the
substance gains heat. For example, if heat is applied to water, it will rise in temperature to a maximum of
100°C — its boiling point. Likewise, if heat is removed, the temperature of the water will fall, to a minimum
of 0°C, or its freezing point. This type of heat transfer, or storage, is called sensible heat.
However, adding heat does not always cause a substance’s temperature to rise. If heat is added to water
that is already boiling, it remains at 100°C, and the absorbed heat instead causes the water to turn from a
liquid into a vapour.
This is a phenomenon common to all pure substances. As they absorb heat, they eventually reach a
melting point (in solid form) or evaporation point (in liquid form), at which point they change state — from
solid to liquid, or from liquid to gas. During this process, they absorb heat but do not get hotter. This type of
heat storage is known as latent heat.
It is this latent heat that enables PCMs to control room temperature. The PCMs used in construction
typically change from solid to liquid at 23-26°C. (Computer simulations show that 26°C is the optimal
phase-change temperature for passive summer heat reduction in buildings, while 23°C is needed for
situations where PCMs are part of a mechanical air-conditioning system.) As they melt, they begin to
absorb heat from the room, rather than simply gaining heat themselves. In this way, the room temperature
can be kept constant until the change of state — or phase change — is complete. The PCM can be
returned to its solid state by night-time ventilation (as long as the night air is cooler than the phase-change
temperature), or by mechanical means in hotter climates. The phase-change cycle is then ready to begin
again the next day.
Types of PCM
There are many types of PCM but not all are suitable for use in buildings. Water, for example, has transition
temperatures of 0°C and 100°C, neither of which are conducive to a comfortable living or working
environment. The selection criteria when choosing a PCM include:
 A melting temperature in the desired operating range — in construction this would be 23°C or
26°C.
 A high latent heat of fusion per unit volume — in other words, they can store a large amount of
heat per unit of volume, minimising the area of PCM tiles that are needed.
 High thermal conductivity. The quicker the PCM reacts to changes in temperature, the more
effective the phase changes will be.

 Minimal changes in volume — substances expand or contract when they change state. Because
PCMs in construction need to be contained within a cassette, large changes in volume could create
problems.
 Congruent melting. This means that the composition of the liquid is the same as that of the solid,
which is important to prevent separation and supercooling.
 A completely reversible freezing/melting cycle.
 Durability over a large number of cycles.
 Non-corrosiveness to construction materials.
 Non-flammability.
The two main types of PCM used in construction are inorganic salt hydrates and organic paraffin or
fatty acids, and both materials have a set of advantages and disadvantages that must be taken into
consideration.
1. Inorganics: salt hydrates
Advantages: Salt hydrates are a low-cost, readily available PCM. They have a high latent heat storage
capacity and high thermal conductivity. They are also non-flammable.
Disadvantages: The volume change between the solid and liquid states is very high. Another problem
with the solid-liquid transition is the danger of supercooling. This is when the temperature of a liquid is
reduced to below its freezing point without it becoming a solid.
Additives called “nucleating agents” can help with this process, but they become less effective over
time. Salt hydrates are also very hygroscopic, which means they trap humidity. By doing this, the water
content varies and the melting point varies as well. This is a danger for long-term stability.
2. Organics: paraffins and fatty acids
Advantages: Paraffins and fatty acids do not expand as they melt, and freeze without much
supercooling, so they do not need nucleating agents. They are chemically stable, compatible with
conventional construction materials and recyclable. Paraffins are hydrophobic, which means they are
water-repellant. As a result, their phase-change points are reliable. Pure paraffins are also highly durable,
and do not degrade in contact with oxygen. Nor can pure materials, consisting of a single substance,
separate from themselves — unlike salt hydrates, which could break away from their water content when
cycled frequently.
Disadvantages: Organic PCMs are flammable and have low thermal conductivity and low latent heat
storage capacity. Impurities reduce heat capacity further, so it is very important that the paraffins used are
in a pure state. This, however, raises the cost, as they have to be completely refined of oil.
When to use PCMs
PCMs are particularly suitable for applications in classrooms, offices, retail or healthcare buildings, which
generally rise in temperature during the working day, through the heat load generated by people and
equipment, but can be purged with night-time air when not in use.

PCMs can be used in the following ways:
 Designed in conjunction with the heating, ventilation and air-conditioning (HVAC) system to maximise
the efficiency of active or passive cooling strategies. From naturally ventilated spaces to integrated
chilled ceilings, most types of HVAC system can be made more efficient.
 To offset the requirement of air conditioning, therefore saving on energy, and energy costs.
 To optimise the use of regenerative cooling and heating sources.
PCMs should NOT be considered in the following circumstances:
 As a replacement for insulation — PCMs act as a thermal storage unit, rather than blocking out or
containing thermal energy.
 On exterior walls — being exposed to solar gain greatly reduces the capacity of the PCM.
 As an addition to existing active cooling or heating.
 As a replacement for air conditioning to manage internal humidity — PCMs only manage thermal
comfort.
Construction materials
Microencapsulation
Construction applications use phase-change materials as they change between their solid and liquid states,
rather than between a liquid and a gas state, as the volume change is far less. This does present the
practical problem of containing the material in its liquid state. An effective solution here is
microencapsulation.
The idea is that the PCM, in the form of a wax, is contained in an extremely hard plastic shell. Each capsule
is tiny — for example, the BASF Micronal DS 5000 X microcapsules used in Armstrong’s CoolZone
products have a diameter of about 2-20 microns — or 0.002-0.02mm. Because the capsules have a very
large surface-volume ratio, they allow a high level of heat transfer, while also protecting the paraffin to keep
it in its pure form.
Pure paraffin is a suitable material for the wax because it undergoes less expansion than other PCMs,
maintains its form in a liquid state and is highly durable — after 10,000 test cycles of the BASF Micronal DS
5000 X microcapsules (which use pure paraffin) there were no damaged capsules. The formulation of the
paraffin wax can be adjusted to give a melting point of either 23°C or 26°C.
PCMs in ceiling tiles
Because heat rises, an effective use of PCM microcapsules is to place them in a cassette and add them to
a suspended ceiling tile. As paraffin is flammable, the PCM insert must be sandwiched between tiles in a
material with a good fire reaction performance, such as metal. A metal tile also offers good thermal
conductivity, pulling the heat through into the PCM. A typical loading of 50% of the ceiling in PCM tiles will
maintain the temperature in an typical mechanically ventilated office at 24°C for up to four to five hours.
After that, the room will continue to heat up as before, until the heating load reduces. The other 50% of tiles
can be service tiles or standard acoustic ceiling tiles. PCM tiles should not be cut and so are not suitable for
perimeter cuts or service penetrations.

With cooler night-time temperatures, the PCM will return to solid form, transferring the heat energy back
into the room. This means that the room is not too cool first thing in the morning but at a comfortable
working temperature, and the PCM tiles are reset for another working day.
Using metal PCM ceiling tiles in this way can lead to significant reductions in energy use. For example,
10sq m of Armstrong’s CoolZone tile can store up to 2kWh of energy. Over a 30-year lifecycle, this saves
6MWh of thermal energy, which would create approximately 1,140kg of CO2, if supplied by mechanical
cooling.
A metal PCM ceiling tile such as Armstrong CoolZone can be dropped into a standard suspended ceiling
grid system, making installation simple. Each PCM cassette weighs approximately 9kg, so grid
strengthening may be required.
LIGHT SENSITIVE GLASS / PHOTOSENSITIVE GLASS
Photosensitive glass is a crystal-clear glass that belongs to the lithium-silicate family of glasses, in which an
image of a mask can be captured by microscopic metallic particles in the glass when it is exposed to short
wave radiations such as ultraviolet light
Photosensitive glass is similar to photo paper; however, it responds to UV light instead of visible light. The
United Nations Secretariat Building at their headquarters in New York City makes use of this technology in
a unique way. Built in 1952, by Le Corbusier and Niemeyer, this 39-story structure is located next to the
East River. The building uses steel frame construction with glass and marble curtain walls. In a 1952 issue
from The New Yorker, Brendan Gill and Gordon Cotler state that the glass walls are made to resemble
marble, which covers the façade of the structure as well. They mention a benefit of the “marble glass” is
that it does not need to be cleaned as often as plain clear glass. In order to give the wall material the look
of marble without it actually being marble, photosensitive glass was used. Each panel of glass used had to
be “baked,” at an extremely high temperature so that the texture and color of the marble would appear on it
in visible light. The image appears like a photograph, but not on paper.
The photosensitive glass walls of the United Nations Secretariat Building are purely for aesthetic value. It is
not just simply a wall of glass. Well, it is, but it does not appear that way. Thanks to Corning, customized
glass can be made—creating the perfect piece of cladding for anyone who wants it.

SELF CLEANSING GLASS
SGG Bioclean
The transparent coating on the exterior surface of SGG Bioclean harnesses both solar and hydro power to
efficiently remove dried water marks, organic pollutants, dust, etc from the glass. To activate the coating,
the self cleaning glass must be exposed to natural light.
DESCRIPTION
A low-maintenance exterior glass that stays clean by itself is what SGG BIOCLEAN stands for. This self
cleaning glass is ideal for most outdoor applications, particularly for areas which are hard or unsafe to
reach out to for cleaning purposes.
PRODUCT APPLICATION
SGG Bioclean has been specially designed to remain cleaner for longer than conventional glass. This
importantly allows using glass in places never thought of before. It is designed for varied external
applications and can be used in all environments and is particularly effective in heavily polluted areas.
The basic applications could be:
 Glazed facades, exterior shop fronts and display windows, overhead and atria glazing
 Conservatories, balconies and overhead glazing
 Windows and patio doors
 Hard to reach areas
RANGE
SGG Bioclean is available on SGG Planilux, SGG Planitherm FUTURN N and many products from
theSGG COOL-LITE range.In the two latter cases, the glass is dual-coated with a coating on each face.
PERFORMANCE
The performance of the self-cleaning function can vary depending on the environment and the location of
the glass such as:
 The type of dirt
 The amount of dirt
 Total exposure to light and rain
 The incline of the installation
Optimum performance is obtained when glazed in a vertical position with maximum exposure to direct
sunshine and rain. During dry spells and in shaded areas, SGG Bioclean still has the ability to clean itself
very easily than ordinary glazing and may simply require rinse with clean soft water.
GREEN ROOFS
The building of green roofs is becoming a good practice in a lot of countries in Europe, especially in
Germany, as well as in the USA (Osmundson, 1999). In the Netherlands a lot of small scale projects has
been realized (Teeuw et al., 1997) but large scale implementation takes much more effort. In a report
published by the municipality of Rotterdam (Anonymus, 2007) a survey is given about the different types of
green roofs with full financial details. Comparison of different types was needed to stimulate large scale
application including suggestions for a system of subsidies (Anonymus, 2007).

The advantages of vegetation on roofs are clear:
 Increase of water buffering capacity.
 Less runoff due to use by plants, transpiration and evaporation.
 Decrease of the amount of water in the sewer system (reducing cleaning costs).
 Improvement of air quality (deposition of particulate matter on leaves for example).
 Reduction of the heat island effect in urban areas.
 Energy savings (increase of insulation capacity – keep building cool in summer and keep cold out in
winter).
 Noise level reduction up to 10 dB(A).
 Increase of lifetime of roofing material.
 Increase of aesthetic values.
 Increase of ecological values.
 Higher selling price of buildings.
A range of different types of designs are now available and realized: from very extensive (ecological roof,
Sedum roof) till intensive roofs (garden and parks).
Greening of outside walls of buildings
The same advantages of vegetation on roofs can be described for greening systems on walls. In recent
years different systems (figure 1) have been developed, like greening direct on the wall, greening systems
before the wall and greening possibilities incorporated within the construction of the wall (Hendriks, 2008).
Despite the range of possibilities there is still great hesitation in the building sector (from the originator,
designer, architect till the builder and the user) to increase the amount of outdoor wall greening. Probably
mainly due to the possible disadvantages: the need for extra maintenance, falling of leaves, chance of
damaging the wall structure, increase of the amount of insect and spiders in the house and the expected
extra costs involved.
Different types of façade greening (from Hermy et al., 2005)
By allowing and encouraging plants to grow on walls the natural environment is being extended into urban
areas; the natural habitats of cliff and rock slopes are simulated by brick and concrete. There is a

widespread belief that plants are harmful to building structures, ripping out mortar and prising apart joints
with their roots. The evidence suggests that these problems have been greatly exaggerated, except where
decay has already set in and plants can accelerate the process of deterioration by the growing process.
Certainly there is little evidence that plants damage walls. In most cases the exact opposite is true, with
plant cover protecting the wall from the elements. Ancient walls still stand, despite centuries of plant
growth.
The leaves of climbing plants on walls provide a large surface area which is capable of filtering out a lot of
dust particles (particulate matter PMx) and other pollutants such as NOx and taking up CO2 in daytime.
Hard surfaces of concrete and glass encourage runoff of rainwater into the sewage system. Many plants
hold water on their leaf surfaces longer than materials and processes of transpiration and evaporation can
add more water into the air. The result of this is a more pleasant climate in the urban area.
What is a green wall?
Photo credit: Patrick Blanc
Let’s focus on living walls, also called ‘biowalls’, ‘vertical gardens’ or ‘Vertical Vegetated Complex Walls’
(VCW). The simplest way is to picture it as a cliff: the synthetic medium is the interface to which the cliff
growing plant species can hang onto. The hydroponic system is often used to create a succession of dry
periods and humid ones.
One of the more important moments in the design process of a green wall is the choosing of species: you
must choose plants which will grow straight and will have beautiful lower foliage, as they will be seen from
underneath. The first living walls used tropical plants but the choice is now much larger. As more recent
green walls create beautiful patterns, it is becoming a new urban art.

Why green walls?
They have multiple impacts on cities and citizens; they protect buildings from the effects of natural
elements; they are introducing more gardens in urban areas and they can even be used to grow
vegetables!
Under sun exposure, a bare wall will contribute to heat conduction inside the building, making the internal
building temperature rise, and contributing to the urban ‘heat island’ effect. But green walls, where the
leaves of plants lose water through evapotranspiration, lower the surrounding air and building
temperatures. Green walls also depress the cities temperature–they create a microclimate.
The Tokyo Institute of Technology proved that green walls lower the energy loss of buildings. They also
prevent the creation of urban dust (partly due to the effect of wind over buildings) and absorb heavy metal
particulates from the atmosphere.
However, the first consequence of living walls is the creation of new green space in cities, where available
space is scarce. Green walls are still newcomers in landscape architecture, and innovation is fast. They are
invading new places every day. On bridges and roads, they can cover ugly or decaying concrete structures,
such as in Mexico City.

Every country invents new solutions to answer its own particular problems. In Canada, where winters are
very long, green walls are placed inside buildings to help offset SAD (Seasonal Affective Disorder).
We need gardens to be happier, even scientists have proven as much with the biophilia hypothesis. Let’s
build some green walls to achieve this goal! One must not forget that as with every green space, green
walls have advantages and drawbacks (such as using a non-biodegradable medium and often huge water
needs) and must only be seen as part of the solution to make our concrete jungle cities greener.
Benefits
Green Roof and Green Wall installations have increased significantly in recent years due to a variety
of aesthetic, economic, and ecological benefits. The following list includes a brief overview of the various
benefits associated with green roofs and green walls.
Aesthetic Value & Improved Health
Green roofs and green walls transform unsightly roofing materials and walls into attractive green spaces
that help restore metal health and well-being. Many studies have shown positive health benefits directly
associated with views and access to vegetation. In the city we are surrounded by utilitarian, even unsightly
building materials such as asphalt shingles, roofing membranes, concrete walls, etc. So, why not consider
a green roof or a green wall to improve your views? The aesthetic and experiential pleasure you derive
from daily exposure to a green roof or wall can translate into increased property value.

Habitat Creation
Green roofs often produce habitats similar to that of meadows or fallow farm fields. Adding a green roof to a
residential or commercial structure effectively recreates the habitat that may have existed on site prior to
development. These habitats attract beneficial insects and birds, bringing nature closer to your home and
restoring urban ecology on your property. As more people install green roofs, our neighbourhoods and city
will benefit from improved & restored urban ecology.
Rainwater Retention
Green roofs are designed to capture and store rainwater to support plant growth. Rainwater on a
conventional roof is directed to downspouts or city infrastructure which can overload a combined storm
water / sewage system, resulting in a series of problems. Like rain barrels connected to downspouts,
rainwater storage and reuse with a green roof or wall makes good ecologic sense. The ability for green roof
plants to utilize existing rainwater means less irrigation. Native and drought tolerant plants further reduce
the need for green roof irrigation. However, a sturdy waterproof membrane beneath a green roof or wall
ensures that your building always remains dry.
Atmospheric Cooling & Moderation
Rainwater captured by a green roof or wall and transpired by its plants moderates surrounding
temperatures. Moist soil and active plants act like a humidifier. During hot summer days this extra moisture
can help cool the spaces around green roofs and walls. On a larger scale, green roofs and walls when
combined with other sustainable strategies can significantly reduce the urban heat island effect. Reversing
the heat island effect would ultimately result in cooler summer temperatures and a much more pleasant
living environment.
Structural Cooling, Insulation & Reduced Energy Costs
Vegetation on green roofs or walls intercepts the suns rays to help keep your house cooler during hot
summer months. The special media used for plant growth acts as an added layer of insulation, further
moderating the internal temperature of a building all season long. During the height of summer, surface roof
temperatures can be reduced by up to 30 degrees Celsius with a green roof. This presents considerable
savings on air conditioning costs. Furthermore, the cooler surface area on a green roof enables roof-
mounted air conditioners as well as solar panels to operate much more efficiently. In a number of different
ways, green roofs and walls help reduce your energy demands and save you money.
Improved Air Quality & Physical Health
Plants convert carbon dioxide and water into oxygen through a process known as photosynthesis. A green
wall in your home, office or commercial establishment can increase oxygen levels and remove harmful
toxins from the air. This results in a better living or working environment and has a positive impact on
physical health. Studies show significant reduction in employee illness when working in a ‘green’ building.
Reducing employee illness has considerable financial benefits for an employer.
Extended Roofing Membrane Life
Replacing a large roofing membrane represents a significant capital cost to a building owner. However,
some estimates suggest green roofs can actually double the life expectancy of your roofing membrane.
While green roofs represent a greater initial investment, a green roof represents a financial savings over
time by doubling the life of your waterproof membrane and providing significant energy savings.

Sound Attenuation & Radiation Blockage
External noises can be reduced significantly with green roofs and walls. Plants, growing media and the void
spaces between particles, as well as drainage board, filter fabric, and a waterproof membrane collectively
perform as a sound barrier. Sound attenuation can be highly effective in urban environments when trying to
reduce automobile noise from adjacent roadways, overhead airplane noise, emergency vehicle sirens, etc.
Green roofs have also been found to block almost all incoming and in some cases outgoing
electromagnetic radiation. With the proliferation of telecommunication devices, transmission towers are now
commonly located on top of buildings where we live and work. Reducing our daily exposure to
electromagnetic radiation with green roofs can have significant heath benefits.
LEED Certification Points
Earn a variety of LEED® Credits for your building project by including green roofs and green walls.
Leadership in Energy and Environmental Design (LEED) is a third-party certification program and an
internationally accepted benchmark for the design, construction and operation of high performance green
buildings.
Marketing Potential & Increased Property Value
Green roofs and walls can increase your property values. Market research has shown a considerable
increase in the lease rates or purchasing prices that can be charged for buildings with ‘green’ amenities
such as green roofs or green walls. Rooftop gardens accessible to condominium tenants can be marketed
as a unique amenity to fetch higher prices per unit. Green roofs and walls make a bold statement about a
person’s or a company’s commitment to environmental sustainability.
Food Production
Vegetables, salad greens and herbs can be grown on a green roof or a green wall. High-end restaurants
that depend on organic and fresh produce have begun to employ green roof and wall systems for on site
food production and harvesting flexibility. As more people question the origin of their produce, local food
production on roofs and walls could become commonplace in our society. Green roofs with meadow
flowers can be used to produce honey with an on site bee hive/apiary. Such food production represents a
cost savings and profit stream for green roof and wall growers.

CII SOHRABJI GODREJ GREEN BUSINESS CENTRE
Project Details
location
Hyderabad, India
Name
CII Sohrabji Godrej Green Business Centre
Developer
The project is a unique and successful model of public-private partnership between the Government of
Andhra Pradesh, Pirojsha Godrej Foundation, and the Confederation of Indian Industry (CII), with the
technical support of USAID
Architectural Design
Karan Grover and Associates, India
size
4.5 acres (total site area)
1,858 m2 (total built up area)
1,115 m2 (total air-conditioned area)
type
Office building
Building details
Office building Seminar hall Green Technology Centre displaying the latest and emerging green building
materials and technologies in India Large numbers of visitors are escorted on green building tour
Ratings
Awarded the LEED Platinum Rating for New Construction (NC) v 2.0 by the U.S. Green Building Council
(USGBC) in November 2003
The building is a perfect blend of India’s rich architectural splendor and technological innovations,
incorporating traditional concepts into modern and contemporary architecture. Extensive energy simulation
exercises were undertaken to orient the building in such a way that minimizes the heat ingress while
allowing natural daylight to penetrate abundantly. The building incorporates several world-class energy and
environmentfriendly features, including solar PV systems, indoor air quality monitoring, a high efficiency
HVAC system, a passive cooling system using wind towers, high performance glass, aesthetic roof
gardens, rain water harvesting, root zone treatment system, etc. The extensive landscape is also home to
varieties of trees, most of which are native and adaptive to local climatic conditions.
The green building boasts a 50% saving in overall energy consumption, 35 % reduction in potable water
consumption and usage of 80% of recycled / recyclable material. Most importantly, the building has
enabled the widespread green building movement in India.

Green features and sustainable technologies
Energy Efficiency
 State-of-the- art Building Management Systems (BMS) were installed for realtime monitoring of energy
consumption.
 The use of aerated concrete blocks for facades reduces the load on air-conditioning by 15-20%.
 Double-glazed units with argon gas filling between the glass panes enhance the thermal properties.
Zero Water Discharge Building
 All of the wastewater, including grey and black water, generated in the building is treated biologically
through a process called the Root Zone Treatment System.
 The outlet-treated water meets the Central Pollution Control Board (CPCB) norms. The treated water is
used for landscaping
Minimum Disturbance to the Site
 The building design was conceived to have minimum disturbance to the surrounding ecological
environment.
 The disturbance to the site was limited within 40 feet from the building footprint during the construction
phase.
 This has preserved the majority of the existing flora and fauna and natural microbiological organism
around the building.
 Extensive erosion and sedimentation control measures to prevent topsoil erosion have als been taken
at the site during construction.
Materials and Resources
 80% of the materials used in the building are sourced within 500 miles from the project site.
 Most of the construction material also uses post-consumer and industrial waste as a raw material
during the manufacturing process.
 Fly-ash based bricks, glass, aluminum, and ceramic tiles, which contain consumer and industrial waste,
are used in constructing the building to encourage the usage of recycled content.
 Office furniture is made of bagassebased composite wood.

 More than 50% of the construction waste is recycled within the building or sent to other sites and
diverted from landfills.
Renew able Energy
 20% of the building energy requirements are catered to by solar photovoltaics.
 The solar PV has an installed capacity of 23.5 kW.
Indoor Air Quality
 Indoor air quality is continuously monitored and a minimum fresh air is pumped
 into the conditioned spaces at all times.
 Fresh air is also drawn into the building through wind towers.
 The use of low volatile organic compound (VOC) paints and coatings, adhesives, sealants, and carpets
also helps to improve indoor air quality.
Other Notable Green Features
 Fenestration maximized on the north orientation
 Rain water harvesting
 Water-less urinals in men’s restroom
 Water-efficient fixtures: ultra low and low-flow flush fixtures
 Water-cooled scroll chiller
 HFC-based refrigerant in chillers
 Secondary chilled water pumps installed with variable frequency drives (VFDs)
 Energy-efficient lighting systems through compact fluorescent light bulbs (CFLs)
 Roof garden covering 60% of building area
 Large vegetative open spaces
 Swales for storm water collection
 Maximum day lighting
 Operable windows and lighting controls for better day lighting and views
 Electric vehicle for staff use
 Shaded carpark
Cost and Benefits
This was the first green building in the country. Hence, the incremental cost was 18% higher. However,
green buildings coming up now are being delivered at an incremental cost of 6-8%. The initial incremental
cost gets paid back in 3 to 4 years.
Benefits achieved so far:
 Over 120,000 kWh of energy savings per year as compared to an ASHRAE 90.1 base case
 Potable water savings to tune of 20-30% vis-à-vis conventional building
 Excellent indoor air quality
 100% day lighting (Artificial lights are switched on just before dusk)
 Higher productivity of occupants

MEASURABLE RESULTS
energy savings 55% reduction, with ASHRAE 90.1 as the baseline 120,000 kWh / year
Reduction in CO 2 emissions ~ 100 tons / year (building is functional since January 2004)
Water savings 35% reduction in potable water consumption
Envelope thermal transfer value U-value of double glazing: 1.70 Watt/m2 °K
U-value of solid wall: 0.57 Watt/m2 °K
U-value of roof: 0.294 Watt/m2 °K
Air conditioning system efficiency0.8 kW/ton (watercooled scroll chiller system with CoP: 4.23 at
ARI condition) Installed two 25 TR chillers
Energy efficiency index (EEI) 84 kWh/m2/year
WIPRO DEVELOPMENT CENTRE
Developer: Wipro Technologies
Location: Udyog Vihar, Phase III
City: Gurgaon
Project Usage: IT Office
Project Architect: Design and Development
Energy Consultant: EDS
Project Start: Completion: 2004 2006
LEED Rating Status: Certified
LEED Rating Type: New Construction
LEED Rating Level: Platinum
Built up Area (Sq ft): 175,000
Material Selection: 40% of the material sourced within 500 miles of the site. Use of certified wood.
Project Highlights/ Special Green features: Energy efficient technologies for non regulated loads. Water
efficiency by use of water saving fixtures.

Factors impacting sustainability
–Effective Use of soil & Landscapes
–Efficient Use of Water
–Energy Efficient & Eco Friendly Equipment
–Effective Control & Building Management Systems
–Use of Renewable Energy
–Use of Recycled/Recyclable Materials
–Improved indoor air quality for health and comfort
Benefits
–Reduces energy and water consumption
–Reduces ecological footprint
–Improves quality of workspace
TECHNOPOLIS
Client: Rahul Saraf
Category: It/office Building
Location: Sector-v, Salt Lake, Kolkata
Total Built-up: 670118.88 Sqft
Duration: 2004-2006
Construction Cost: 99 Crores
Structural Consultants: Pedric Error + Sanjiv
Parekh Associates, Kolkata
Façade Consultants: Glasswall Systems, Mumbai
Mep Consultants: Entask, Kolkata
Landscape Consultants: Design Accord, Delhi
As a pioneer of its time, Technopolis has the distinction of achieving the “Gold Rating” from The U.S. Green
Building Council. The project incorporates several green features that amount to about 35% of energy
savings. Considering the fact that any IT edifice houses employees who work under a lot of pressure
around the clock, trying to meet the demands of deadlines, it is but inevitable that the architecture around
them has to be pronounced in such a way that it provides relief, both visually and physiologically. The
challenge of design, therefore, lay in providing a sense of openness in a high density development. We
knew from the beginning that we wanted the building to incorporate characteristics of a public square or a
public campus, both of which suggest interaction and social interface, and thus creating spaces that would
act as a buffer between home and workplace.
The project sits on 2 acres of land with a total built-up area of about 6.3 lac sqft. accommodated in 16 floors
and houses approximately 7000 employees. As part of the design, it was decided to open up the ground
floor with an unobstructed view of the main approach interface that occupies a large expanse. About
30,000 sqft. of space has been planned with triple height which covers the driveway and the entrance foyer.
A full height glass wall supported by spider-fixture system on metal structure has been used to divide the
driveway & foyer. This particular element has provided multiple opportunities in incorporating design
sophistication, landscaping & interior planning. The 20,000 sqft. portico is covered with a metal roof
supported on inclined steel columns. The large span structure with 40 ft. high ceiling generates a total

sense of openness. The sloping grass patch partially protruding in the covered area of portico further adds
to the purpose of this “Techno Environment”.
The overall building mass has been split into two volumes and treated with glass in different colors. To gain
full advantage of the northern orientation, maximum glazing is applied with varying characters. Façades
facing south & west have been provided with large overhangs and minimum glazing. The six storied high
void acts as a courtyard and helps in façade articulation. The terrace garden in the front extends into this
courtyard and generates about 20,000 sqft. of green space for employee usage. The loss of openness due
to high ground coverage could be recompensed with the large terrace garden at 2nd floor level. The first
floor in its entirety has been spared to provide common amenities such as a large food court, coffee shops,
bookstore, training center and others. Health club facilities have also been provided on the top floor
adjacent to the terrace garden.
In all, Technopolis, as far as IT office buildings are concerned, has turned out to be a combination of
sophistication and sustainable design example, a well-rounded representation of our initial intentions to
provide buffer spaces for the well-being of its employees while adhering to green design principles.

GRUNDFOS GREEN BUILDING
Grundfos Green building - A symbol of responsibility and sustainability
Grundfos, the Danish pump major has always been in the forefront of delivering sustainable pump solutions
with a clear vision for the future, etched on strong fundamental values. Like their products, their product
innovation, in-house production process, usage and choice of materials and new technologies highlight
their sincere desire on World's resource conservation, with minimal impact on the surrounding environment.
'The overall Grundfos goal is that when this generation delivers planet Earth to the next generation, it
should be a cleaner and more energizing place than the place when we inherited' says the Group Chairman
Mr.Niels Due Jensen. Hence, it is a logical turn for Grundfos India when it built its new facility in March
2005, as 'Green Building' which symbolizes its core values and the positive way they wished to conduct
their business in India.
Grundfos have achieved 42 points out of 69 points in LEED rating leading to be certified as the First Gold
Rated Green Building in India. Grundfos managed to score four out of five in innovation and design process
and 12 out of 15 in indoor environmental quality. However, they were able to achieve five out of 17 points in
energy and atmosphere category.
Table I: Points achieved by Grundfos for their Green Building under LEED rating.
 Double skin brick wall with 25mm air cavity, double-glazed low U glass to minimize the heat ingress
into the building thus minimizing the building heat load

 Hydro Fluoro Carbon (HFC) based Chillers with a high Co-efficient of performance (COP - 2.7) and
with thermal storage system to minimize peak and connected load
 Continuous monitoring and maintaining fresh air (around 15-20 CFM per person) by effective CO2 level
monitoring through Sensors, installed at key locations of the building

 95% of the time, the daylight is used due to open lighting Architectural construction
 'Zero discharge' of water due to 100% waste water recycling and its economic use for irrigation and
flushing of toilets
 Less usage of low Volatile Organic Compound (VOC) sealant / carpets / composite woods / paints to
reduce air pollution to maintain good indoor air quality
 10% of the building materials used for the construction of the building are either refurbished or
salvaged from Grundfos old offices to minimize the use of virgin materials
 Less usage of low Volatile Organic Compound (VOC) sealant / carpets / composite woods / paints to
reduce air pollution to maintain good indoor air quality
 43% reduction in potable water usage installing water efficient fittings like dual flush toilet, sensor
based urinals, waterless urinals and low flow fixtures
 Rainwater recharge pits to improve groundwater levels in the surrounding areas
 60% of the materials used in the building have high recycled content (Al, Steel, Glass, Brick, Fly ash
cement, MDF wood)
 Native plants to minimize water requirement for irrigation and uprooting and re-planting of 'the already
existing trees' within the premises
 High efficiency irrigation system like sprinklers for lawn & drip irrigation for trees and shrubs.
 Limiting building foot print to have more open spaces for landscaping
 Shower & changing facilities for the bicyclists, battery operated vehicle's charging facility
 Rainwater recharge pits to ensure zero discharge to municipal drainage
 Most non-roof impervious surfaces around the building are shaded by the use of mature vegetation to
minimize the heat island effect
 No smoking zones created all over the building

The Olympia Tech Park covers 1.8-million square feet in Chennai, Tamilnadu. This is considered as the
largest green building in the world. This building was awarded with LEED Gold certification.
"Olympia Tech Park has the lowest energy consumption, high natural lighting systems, 100 per cent water
recycling and other environment-friendly practices," says Ajit Chordia, managing director of Khivraj Tech
Park Pvt Ltd, which owns Olympia Tech Park.
The building plays host to companies like Hewlett-Packard, ABN Amro, Visteon, Mindtree Technologies
and Verizon.
At present, a third of the power required to run the building is met through renewable energy sources. With
the opportunity to meet two-thirds of power requirements through renewable energy sources and other
green practices over the next two years, the tech park has more carbon credits to gain in the pipeline.
Olympia Tech Park stands to earn revenues in the region of Rs 1.50 crore a year, to begin with, by forward
trading incertified emission reductions (CERs) or carbon credits.
"In our case, returns via carbon credits amounts to just 2 per cent of our revenues," says Chordia, adding:
"But the goodwill generated among our participant companies is unlimited."

"The long-term gains from energy efficient sources like air-conditioning, renewable energy sources like
recycled water, efficient ventilation systems and lesser carbon emissions will result in annual savings of at
least 20 per cent of our overall maintenance expenses," says a developer.
The park has applied for registration with the United Nations Framework Convention on Climate Change
(UNFCC), as a forerunner to entering the lucrative carbon credit trading market.
"We expect UNFCC approval within three weeks, following which we will commence carbon trading. We
expect to generate 20,000 CERs annually for now, but will generate more carbon credits as we comply with
additional compliance norms laid out under the Kyoto Protocol," Chordia said.

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