Technology behind Green Building towards Energy Efficiency

M. Saikia, R. Bhowmik, D.C.Baruah

Department of Energy, Tezpur University

madhurjyasaikia3@gmail.com

rajibaec@gmail.com

baruahd@tezu.ernet.in

Abstract- In India, conventional buildings

consume high amount of resources in

normal functioning. This study discusses

various relevant renewable technology used

in green building in order to optimize

resources usage. Moreover, this study also

tries to investigate problems experiencing in

wide popularity of green buildings in actual

ground as market penetration of the

technology is important for survival.

Keywords - Building materials, design,

environment

I. INTRODUCTION

Energy conservation is the need of

time. One of the sectors which seriously

need attention is the household sector.

Inefficient building design is the root cause

of high energy consumption in household

sector. From this backdrop, the concept of

green building has risen. Green building is

actually those buildings which optimally use

resources like energy, water, and materials.

They are not only green from operation but

also from construction point of view. The

contour or design of this type of building is

site specific. Therefore, a simple building

cannot be a green building even with it

energy saving features. It starts from the

very beginning of design. LEED-INDIA is a

Green Building Rating System which is a

nationally accepted benchmark for the

design, construction and operation of high

performance green buildings.

II. TECHNOLOGY FOR GREEN BUILDING

A building interacts with the

environment through its external facades

such as walls, windows, projections and

roofs. Each component contributes to energy

efficient feature of the building. Of the

various factors, site plays important role.

The design of building may change

according to site as environmental

conditions are influenced by micro climate

and macro climate as well. Site specific

conditions like water body and vegetation

influences the design. The green building

design could not come out without

considering these conditions. This generally

helps to have a suitable indoor environment

throughout the year. Orientation of building

is a necessary part of the green building plan

and design. The best orientation is that the

buildings should receive maximum solar

radiation in winter and minimum in summer.

Therefore, we need to check sun’s position

in daily and seasonal basis by sun path

diagram. Determination of orientation of

building helps to control heat and wind

entering the building by (1) type of

glazings, (2) types of walls and roofs, and

(3) shading and (4) aperture

Geometry of building should be

appropriate to the climate and this helps in

greater way by controlling heat flow

magnitude. Suppose for a building in a cold

area, one need to minimize heat loss. For

that purpose, many techniques could be

undertaken as for example infrequently used

spaces could be placed in the direction of

house which faces cold winds and

maximizing exposure to habitable spaces.

Similarly, building geometry in hot climatic

area would change. The geometry for

commercial buildings in hot climatic zones

could be Central Atrium which uses the

thermal chimney effect. This effect produces

natural ventilation. During the day, air

warms up and floats up to the ceiling. This

warm air is siphoned off using fans at the

top of the exhaust columns and by

computerized windows at the top of the

atrium. The hot air is replaced by fresh air,

which is collected at ground level on the

shaded north side of the building. This

system reduces the pressure on HVAC

system and thereby reducing energy

consumption.

The heat flow due to radiation and

air movement can be controlled by varying

parameters of building geometry such as

surface area to volume ratio, shape of the

building, buffer spaces, arrangement of

openings and shading. The ratio of the

surface area to the volume of the building

(S/V ratio) depicts the magnitude of the heat

transfer in and out of the building. By shape

of building the wind pattern can be shaped

according to the need. Buffer spaces give

shading and catch wind while the shading

surfaces reduce heat gain. Generally, Walls

can be shaded by the use of projections,

balconies, fins, textured paints and

vegetation. Openings can be shaded with

appropriately sized chajjas and fins etc.

The building components such as

roof, walls, ground-based floor, fenestrations

external colour and texture involve

application of lots of different types of

material and basic science. Even by

modification in construction material in

building components can contribute a lot to

the energy efficiency. The green concept

starts with bricks. Some of these are

stabilized mud block; compressed earth

block, fine concrete blocks, clay fly ash

brick etc can replace conventional materials.

They have low energy consumption in

production. Now a day, lime is used in

foundation rather than cement while white

roof coating is used reflects 70 to 80 % of

the incident sun's energy.

Apart from building material,

sometimes additional structures are required

for heating, cooling and lighting needs.

Passive heating in cold climate can be

practiced in order to lessen dependency on

electricity or other means. In this approach,

bare massive walls or floors are provided to

absorb and store heat. This is the direct

heating method in which main components

are (1) glazing, (2) thermal mass (3)

insulation to reduce heat losses at night (4)

ventilation (5) shading. For more heat gain,

clerestories and skylight can be used. On the

other hand, in indirect gain approach solar

radiation is prevented from entering living

space and solar energy absorption and

control take place outside it. Trombe wall,

water wall and trans wall are some of the

examples of thermal storage used in this

application. Roof collectors like thermo

siphon air panels can be installed on south

facing rooftop (northern hemisphere) which

uses only the buoyancy of heated air to

circulate air through the collector,

eliminating the cost, maintenance, and

energy consumption of fans, sensors, and

controllers commonly used in other collector

designs. Similarly, in hotter regions there is

a great demand of cooling. Passive cooling

techniques like solar chimney and wind

tower which wind pressure for cooling are

useful. Like indoor air conditioning, lighting

is also important and consumes a good

portion of the energy usage. Though,

windows and doors serve the normal

purpose of lighting, some extra systems like

light pipe, light well, sun tracking unit and

Himawari system can enhance lighting and

thereby offsetting energy cost. Moreover,

lights with sensor and CFL have already

gained popularity in household application.

III. VIABILITY OF GREEN BUILDINGS

In response to growing concern

regarding climate change, people have

started thinking in energy conservation in

every sphere. The positive outcome is green

buildings instead of conventional homes

developed by corporate houses. These

houses look alike and do not have slightest

percent of energy efficiency feature as they

are developed in bulks. Though, the green

buildings are environment friendly and

stakeholder in sustainable development, still

they are lacking in practical application even

though repetitive trials by various

governments. The reason is simple. It

consumes quite large sum of investment to

develop such a project. According to CB

Richard Ellis, development of a greener

building designed to achieve one of the

higher standards of accreditation is likely to

add between 5% and 7.5% to construction

costs. In USA, the trend of development has

showed that an increase of 0-3% in capital

cost for the lower ratings, and up to 6.5%

cent for the highest ratings. The same

situation is applicable in Indian markets. The

extra cost burden has to be shouldered by

the buyers in order to have one green

building i.e. higher environmental standards

cost more. The best way to cut expenses in

building green houses is- sourcing the right

materials, using the right professionals and

securing suitable design features. In

addition, wide variations in the

responsiveness of planning and building

control authorities, which will introduce

market specific variation in total

development costs. Adoption of green

houses is also dependent on fluctuation of

oil prices. In some short time period, if oil

prices dip then this would surely inhibit the

adoption of green buildings by reducing the

absolute scale of cost saving achievable.

IV. CONCLUSION

The green building concept demands lower

energy consumption in every respect

whether construction or materials those are

being prepared for construction. In today’s

world modern buildings are designed by the

engineers and architectures so that it look

nice. But energy consumed on those

buildings are much higher as they use

conventional energy during construction.

Use of locally available materials for

production will cut down transportation cost

of building materials and also will save

energy.

ACKNOWLEDGEMENT

The authors sincerely acknowledge the

helpful inspiration from Professor

D.C.Baruah and also we are grateful to all

faculty members of the Department of

Energy, Tezpur University for their valuable

support.

References

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