Energy efficient buildings

Energy Efficient Planning and Design Of Buildings

Ar.Kirti D. Bhonsle, Asst.Professor, Aayojan School Of Architecture, Jaipur [Raj.].

Introduction-

Climate change is a very real problem. India is clearly one of the countries, which is vulnerable to climate

change impact in a very significant way. Apocalyptic list includes accelerated frequency of extreme weather

events, changes in long term precipitation patterns, a rise in sea level and an increased spread of water

borne diseases such as malaria and dengue.

In terms of the per capita emissions of the greenhouse gases that may cause climate change, India is less

than one quarter of the global average and is less than one-twelfth of the U.S. per capita emissions.” Even

though our economy is set to grow at the pace of 8-9% our emissions are much lower than many countries.”

� Accelerated glacial melt around the Himalayas will eventually lead to a significant scarcity of water

resources across India.

� Increased water precipitation might mean that certain states get flooded and face drought in the

same year.

� Rising sea levels would have disastrous consequences for coastal areas, inundating low-lying

habitation structures.

� Extreme weather events like tornados and cyclones will occur with increasing frequency and greater

severity.

� India is highly vulnerable to the impacts of a human induced climate change in coming years.

A hurricane in the New Orleans, floods in Mumbai, Bangalore and Chennai and now a cold wave in North

India. The frequency of extreme weather events has got many asking one question –

Are these severe occurrences caused by natural vari ability or are they the effect of a human induced

climate change?

An Awakening Call-

A human induced climate change clearly points towards the degree of responsibility that each individual

human being on the planet should have towards “Saving the Planet” . All the sectors of economy like

Industry, Agriculture, Software Technology, Science and many more must work for this common cause,

which is the basis of our survival.

It is energy that has kept us empowered through the ages and is the guiding factor that keeps things rolling

on, on all fronts. The building sector is growing at a rapid pace and is the third largest consumer of energy,

after industry and agriculture. The buildings tend to create environmental problems that are affecting the



ecosystem. Consciousness among people involved in building industry lead to a number of views on this

issue that can be broadly summarized as –

� Reformist – A radical change in the social and cultural values with economic growth ceasing to be

the panacea for prosperity and well being and with the family and community taking precedence over

the individual look to –

- Simple lifestyles,

- Local labour and materials,

- Return of used resources

- A local but global approach.

� Reactionary – Propagators of this type of approach advocate the philosophy of

- Green Architecture

- Bioclimatic Architecture

� Revolutionary – This group thinks by the way of technological fix by harnessing technology in an

appropriate manner. In an Interventionist approach they prefer to coerce society to form new

structures and communities. The architecture is assertive, glossy and of the moment.

Talking of the “energy efficient planning and design of buildings” will be the same as thinking of the

green perspective in architectural history, which is popularly known as “Vernacular Architecture ” or the

“Vernacular design of buildings”

Evolutionary process of architectural endea vor

But as we all know that just thinking of the past makes a coward of us, just being in the present

makes us static but being in the present with due regard to the past and with the knowledge to formulate the

future will add dynamistic touch to our initiatives and interventions.

[Vernacular Architecture]+[Technology Advancements]+[Green Architecture]= Bioclimatic Architecture

Considering architecture as an environmental custodian Green Architecture is seen as a reaction to

the predicament of environmental depredation. The environmental crisis that currently faces us has focused



attention on the impact buildings have on the environment. Our perspectives have widened from trying to

radically reduce energy use to trying to achieve a sustainable equilibrium in use of resources.

Architecture is considered to be the reconciliation of the intuitive and the rational ideas, thus deriving

a close relation between building, site and nature. First we had nature and hen came the environment.

Environment is the smoke humanity has cast on nature. Environment and green mean numerous and

different things: they have lost any precision they might have had when coined.

Green Sensibilities include the following –

*Responses to the natural climatic forces

*Utilization of resources

*Historical relationship between architecture and environment.

Issues-

Protection of the globe through radical re-evaluation of the way buildings are designed and constructed

reflects the concerns of the Green Movement generally. The remedial measures given for the global

depredation are –technological innovation, rational planning, appropriate specification of materials and an

effective building system management. On the other hand bioclimatic describes an approach to building

design which is inspired by nature and which applies a sustained logic to every aspect of a project, focused

on optimizing and using the environment. The logic covers conditions of setting, economy, construction,

building, management and individual health and well being, in addition to building physics.

CII-Sohrabji Godrej Green Business Center has been launched in India to offer the much needed Green

Services to the Indian Industry. The buildings mentioned above have been awarded the coveted Platinum

rating from US Green Building Council [USGBC] under the Leadership in Energy and Environmental Design

[LEED] programme. The one in Hyderabad is the first ‘Platinum Rated’ building outside the US and the third

in the world.

1] CII-Godrej GBC,Hyderabad, LEED Platinum 2]ITC Green Centre ,LEED Platinum



Energy Efficiency-

Some of the energy efficient measures that are constant wherever the building is located are –

* Embodied, grey and induced energy – Energy use in the manufacture of the materials,

components and systems: in their distribution and transportation and in the construction of building needs to

be husbanded and minimized wherever the building is located.

Material Size[cms] Block size Energy/block[MJ] Energyinbrickeq.[MJ] Blockenergy

Granite stone 18x18x18 0.325 0 0 0

Burnt brick 23x11x7.5 1 4.5 4.5 100%

Stabilized mud block 23x19x10 0.434 2.73 1.18 26.20%

Hollow concrete block 40x20x20 0.118 9.2 1.09 24.20%

* Comfort management – The management of the comfort systems in a complex building and the

split between the central and local management and control of systems will not only affect the efficient

performance of the building but influence the occupants identification with it, their sense of being a part of it

and the manner in which it delivers comfort.

The energy consumed in the life of a building. The graph above shows how energy is consumed over the 60

years life of a building. The flatter the incline, the more energy efficient is the building. This was arrived at by

the researches carried out in BRECSU.



* Energy generation – Local energy generation using renewable sources –winds turbines,

photovoltaic and biomass etc.- minimizes greenhouse emissions wherever the building is located but

different regions will favour different renewable systems.

TOTAL ENERGY IN BUILDINGS

4.2

2.65

0.930.21 0.13 0.046

5.83 5.835.83

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energy/sq.m[GJ] equivalent coal tons energy in 25yrs/sq.m[GJ]

Planning and Design of Buildings-

The key aspects in the design of a building should be its “comfort criteria ” that varies with an individual, a

group, physical activities and the psychological state of mind of the occupants. The effective way of

designing a building is by exploiting the natural forces i.e. by harnessing the beneficial attributes of the

climate without recourse to mechanical systems that is popularly known as the ‘passive solar design’ .

ENERGY IN BUILDING MATERIALS

5.85 5.63 2.33

42

236.8

25.83

100

3.75

206 200

0.220

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1kg 1kg 1kg 1kg 1kg 1kg 1kg 1no. 1cu.m 1sq.m. 1ml

Cement Lime Lime+Flyash Steel Aluminium Glass GRFP Brick Sand Marble Polyster

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unit[

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Solar chimneys as shown in the sketch above are the flues constructed to exhaust air from a building using a

combination of stack effect, external pressure differentials and the heating of the flue by sun so that cooler

air is drawn to fill the vaccum.

Similarly the designs of the thermal storage walls and the green house spaces as shown below help in

preventing the direct heat gain from the sun and is found very effective.

Shaping the roof profile helps in increasing

the area of sheltered region that is to be

provided in a building against adverse winds



The sketch above shows the solar thermal collector, which is a device for collecting solar energy in the form

of heat, usually by exposing a fluid to the sun’s rays. The sketch adjacent to it shows the orientation of the

buildings with the longer axis along the east-west direction with larger overhangs on the southern side

provides protection against the harsh sunrays in hot-arid climates. On the other hand the buildings in the cold

regions need to have glass facades on the southern facing of the building to be able to trap the maximum of

the solar radiations to keep the interiors warm and comfortable.

Passive solar designs also depend on the quantum of exposed surfaces of the building to the sun’s rays

which is clearly explained by the sketches below where a cube with unit dimensions has been taken -

Evaporative cooling is another passive means of

providing thermal comfort in the buildings as is shown in

the two sketches where the properties of water to

gradually gain heat in the day brings cool air inside the

house and gradually lose heat at night brings in warm

breezes in the night thus providing favourable conditions

in the buildings near water bodies.

The other sketch shows the next version of water films

being used as solar thermal collectors.



In the first case the cubes have been so arranged in the simplest of ways wherein the volume is 8 cu.units

and its surface area is 28 sq.units.

In the second case the volume being the same as 8 cu.units, the arrangement is so done that the surface

area is reduced to 24 sq.units thus lowering down the amount of exposed surfaces of the cube. This still

brings down the possibility of solar gain by the various building materials so used in the buildings

construction. The exercise clearly points out that proper clustering of the building blocks helps in reducing

the exposed surface area which in turn reduces heat gain by the building.

Stack effect shown in the building section shows the

vertical movement of air caused by convection, the

phenomenon by which hot air rises pulling cooler air in

to fill the vaccum. The hot air is usually expelled at high

Level



The provision of the thermal storage wall with a thermal mass, tells about the capacity of a material to take

up heat from the surrounding space. A material of low thermal inertia, such as stone or concrete, can be

used to absorb heat during the day when temperature are high and release it at night when it is cooler.

Vegetation – Effective vegetation cover can help in protecting the building from the direct heat gain of the

sun. More so in cold regions, the rows of deciduous plantations on the west face of the building provide

• Heat gain in winters as the tree sheds its leaves in winters and provide

• Protection from the direct rays of the sun in summers as the tree is in its full bloom with thick foliage.

Roof space can be insulated using materials like batts, loose fills, blankets etc. Even the installation of

the solar water heater on rooftop can provide good insulation and sufficient ventilation of the roof space.

Floor space insulation can also be achieved by proper carpeting, batts, provision of wooden or vinyl flooring

etc.

Small windows can be provided with effective louvers to reduce the heat transfer on the other hand large

windows can be provided with solar films, awnings, reflective curtains etc along with proper weather

stripping. Windows or openings can also be provided with a variety of shading devices horizontal, vertical or

of the egg-crate type increasing the extent of shaded area of the window.



Pergolas, shade slats can be positioned to offer best protection to the building along with the breezeblock

walls to prevent the direct winds and sun to strike the buildings thus improving comfort conditions within the

building.

Along with all these passive means of solar design and many more what is required is optimizing orientation,

finding a balance between sun shading and sun trapping, installing windows that open to its best effects but

when closed are properly weather stripped, insulating well and ensuring leak free construction that also

involves understanding the thermal performance of the materials, planning the interior to mitigate the

extreme thermal fluctuation and landscaping to create complementary external condition.



Conclusions -

Modest buildings at a small scale can achieve absolute comfort conditions with purely passive solar designs

but in buildings of a larger scale with high occupancies the situation becomes difficult calling in for the

combined usage of the passive along with the active means of thermal comfort. A building that combines the

exploitation of the natural forces with carefully conceived and orchestrated use of artificial measures to

produce energy efficiency is known as mixed mode building.

Typical cross section showing the mixed mode energy strategy used in this building.

The main entrance of the

Barclaycard Headquarters,

Northampton, U.K.

Climatic zone –Temperate

Features –

Orientation –north-south

Ventilation – natural and night time

both

Solar control systems

Thermal mass storage

Daylighting

Energy saving controls for artificial

lighting.

Use of mixed mode energy strategy



Some of the issues that need to be addressed in the design of contemporary bioclimatic buildings and

settings are threefold -

• Energy

• Health and well being

• Sustainability

# Over and above the measures needed to provide comfort in energy efficient manner are that

affecting energy consumption in construction generally. These apply regardless of the climatic zones. They

include embodied, grey and induced energy, which calls for renewable energy generation and efficient and

responsive management of energy systems. The embodied energy is the energy consumed in the

manufacture of building materials, components and systems.

# The W.H.O. Has defined Health as “A state of complete social, physical and mental we ll

being of a person.” With this in mind, the aim of the building is Shelter, Security and Well-being.

There are some buildings that tend to cause a Sick Building Syndrome, which is a combination of the health

malfunctions, which affect a significant percentage of a buildings population. The effects include lethargy,

headaches, respiratory infections, eyestrain and dryness of the eyes, aching muscles and asthma, which are

not experienced by occupants when away from the building. There are a number of apparent causes of SBS

which include air conditioning, sealed windows, re-circulated air, high density occupation, smoking, air borne

micro organisms, dust and dust-mite excrement.

# Sustainability is the concept of managing the use of natural resources so that the amount of the

resource is not irretrievably depleted. The development of renewable alternatives to non-renewable

resources is essential and the stock of renewables in use must be maintained. Economic development taking

place in this way is termed “Sustainable Development ” and is defined as development that meets the

needs of the present without compromising on the ability of the future generations.

In a way the passive solar or bioclimatic building has to mimic the attributes of an organism by trying

to accommodate the climate’s capriciousness. It may mean a constant adjustment of the building envelope



i.e. one-quarter of a buildings wall surface must be capable of opening and closing, one-third be capable of

introducing uninterrupted daylight and a similar area must allow sunlight to enter at certain times and screen

it at others and by degrees. More so all these functions to happen without interfering with the buildings views

to the outside.

With the uncertainties of the climate which we discussed in the beginning and then of the passive

solar designs, mixed mode designs and so on we can look forward to the day when adjustments in building

fabric and service systems in response to the changing meteorological conditions and modes of operation

will be activated by the onset of change of climate itself or even in anticipation of it. When this happens the

“Intelligent Buildings” would have truly arrived.

Whatever may be the level of sophistication of technology in the future but the goal to reach should

be a sustainable building that over its life breaks even or is in credit in respect to energy consumption. As

providers of a central link between man and nature, architects through their designs need to enlighten the

path to wards sustainability in architecture.

References –

• Venkatarama Reddy.B.V, Progress of Stabilized Mud Block Construction in India, Proc. National

Workshop on Alternative Building Methods, Deptt. Of Civil Engineering, IISc, Bangalore.

• Haseltine.B.A, Comparison of Energy Requirements of Building Materials and Structures, The

Structural Engineer, No.9, Vol-59, 1975.

• David Lloyd Jones, Architecture and the Environment-Bioclimatic Building Design, Lawrence King

Publishing.

• Connaughton,J.N.,Real Low-energy buildings:the energy costs of materials, Eds.SusanRoaf and

Mary Hancock, Blackwell Scientific, London, 1992.

Energy efficient buildings

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