Energy Efficient Solar Homes Buildings

8/2/2019 Energy Efficient Solar Homes Buildings

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About TERI

TERI, established in 1974, is a not-for-profit, non-government research organization deeply committed toevery aspect of sustainable development. Over the years,TERI has been working with governments, multilateralorganizations, and corporate entities in providingcomprehensive support on aspects such as policy issues,project evaluation, and technology.

About MNRE

Akshay urja se desh vikas

Ghar ghar bijli, gaon gaon prakash

In 1982, the Government of India set up the DNES(Department of Non-conventional Energy Sources). Thiswas upgraded to the MNES (Ministry of Non-conventionalEnergy Sources) in 1992, and is now known as the MNRE(Ministry of New and Renewable Energy). The MNRE is thenodal ministry for all matters relating to the development

and promotion of new and renewable energy in the country.

Ministry ofNew and Renewable Energy

Government of India

The Energy and Resources Institute

For more information, please contact:Ministry of New and Renewable EnergyBlock No. 14, CGO Complex, Lodhi RoadNew Delhi - 110 003Tel. 011 2436 2488Fax. 011 2436 9788

Website: www.mnre.gov.in


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Energy efficient solar homes/buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Design aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Climatic zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Passive design features and their advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Orientation of building. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Sunshades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Window design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Double glazed windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Building insulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Roof treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Evaporative cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Landscaping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Surface to volume ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Passive heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Earth air tunnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Solar chimney . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Wind tower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Applicable passive features for various climatic zones . . . . . . . . . . . . . . . . . . . . . . . . . 10

Hot and dry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0

Warm and humid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Moderate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Cold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Composite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Energy-efficient lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

I n d o o r l i g h t i n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

Outdoor lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Energy-efficient a ir c onditioners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3

Selecting the right size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Selecting an efficient AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3Installing an AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Renewable energy devices/systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Solar water heating system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Building integrated PV system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

Other r enewable e nergy d evices/systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Annexure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

List of architects/experts and institutes/organizations with experience

in designing energy-efficient homes/building. . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

List of State Nodal Agencies for new and renewable energy. . . . . . . . . . . . . . . . . . 20

List of manufacturers of solar energy systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

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This information booklet has been prepared with financial assistance from the MNRE.No part of this publication can be transmitted in any form without prior permission of theMNRE and TERI.

Publication and editorial team:Dr A K Singhal, Director, MNREMr Dilip Nigam, Principal Scientific O fficer, MNREMs Mili Majumdar, Associate Director, TERIMr Gaurav Shorey, Research Associate, TERIMs Shraddha Mahore, Research Associate, TERIMs Pallavi Sah, Information Analyst, TERIMr T Radhakrishnan, Print Production Specialist, TERIMr Tamal Basu , Illustrator-Cum-Graphic Designer, TERIMs Archana Singh, Visualizer, TERI

Mr Mahfooz Alam, Graphics Assistant, TERI

Published by:The Energy and Resources InstituteDarbari Seth Block, I H C ComplexLodhi Road, New Delhi 110 003Tel. +91 11 2468 2100, 2468 2111Fax. +91 11 2468 2144, 2468 2145

DisclaimerThe MNRE (Ministry of New and Renewable Energy) and TERI (The Energy and ResourcesInstitute) do not assume any responsibility for the authenticity of the design, costs,performance data, and any other information contained in the booklet. The MNRE and TERIwill not be liable for any consequences arising out of use of any information or data c ontainedin the booklet.

Ministry of New and Renewable EnergyGovernment of IndiaBlock No. 14, CGO ComplexLodhi Road, New Delhi 110 003

CONTENTS


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ENERGY EFFICIENT SOLAR HOMES/BUILDINGS

Design aspects

The design of energy efficient solar homes/buildingsdepends on climate, solar path and intensity, humidity,wind flow, and ambient temperature of a particular place.Design parameters of homes/buildings, therefore, vary with

different climatic zones of the country.

Efficient solar homes/ buildings have been constructed in afew states as initiatives of the MNRE (Ministry of New andRenewable Energy). The governments of Himachal Pradesh,Punjab, Haryana, and Nagaland have made it mandatory toconstruct all buildings using passive design features. Thefollowing are the three fundamental strategies that

can be adopted to reduce energy consumption inhomes/buildings.

Incorporating solar passive techniques in a buildingdesign and enhancing building material specificationsfor minimizing the load on conventional systems(heating, cooling, ventilation, and lighting). Passivetechniques vary with climate, and simple techniquesthat are useful for new homes/buildings in differentclimates of India are listed in booklet.

Designing energy-efficient lighting and HVAC (heating,ventilating, and air conditioning) systems in

homes/buildings.

Homes/

buildings

that

incorporate

concepts of

solar passive

design and

utilize

energy-

efficient

equipment

and devices,

which run on

renewable

energy, are

called energy-

efficient solar

homes/

buildings.

Such homes/

buildings

provide

comfortable

living and

working

conditions,

both in winter

and in summer,

with minimal

consumption of

electricity.

Energy efficient

homes/

buildings can

save over 30%

to 40% of

electricity used

for lighting,

cooling or

heating.

Integrating renewable energy systems, such as solarphotovoltaic systems and solar water heating systems,with buildings to meet part of their load.

We all know that the sun travels daily from the east to thewest. Its movement from the north to the south and thesouth to north results in seasonal changes duringthe year. The orientation of a building in aparticular direction, therefore, can heat or cool

the building depending onthe climatic zone in which itis construct ed. Properorientation can help increaseor decrease the heat load by5%. For example, if the longsides of the building in thecomposite climatic zone facenorth and south and theshort sides face east andwest, the heat load canbe reduced.

PASSIVE DESIGN FEATURES AND THEIR

ADVANTAGES

Orientation of building

Climatic zones

The country can be divided into five climatic zones.

Some cities that fall in these zones are:

Zones Cities

Hot and dry Jodhpur and AhmedabadWarm and humid Chennai and Kolkata

Moderate Bangalore

Cold Leh, Shillong, and Shimla

Composite Bhopal and Delhi

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The orientation of a buildingdetermines the total amount of

energy required to heat or cool it.

Integrated PV panels generateelectricity while looking likea part of the building design


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Sunshades

Window design

Double glazedwindows

These are installed at the top ofwindows/doors to obstructsunrays that enter the buildingduring summers but allow themto enter during winters. Thishelps protect the building

from over heating duringsummers and keeps it warmduring winters, thereby reducingelectricity consumption whichotherwise, would increasedue to heavier use of roomcoolers/heaters.

Windows in a building allow light,heat, and air to come in. While

day light and air are welcome in buildings in

all climatic zones, heat may or may not berequired, depending on the climatic zonein which the building is constructed.

Therefore, decision regarding location of windowsshould be based on therequirement of heat in thebuilding. The sizes ofwind o ws a nd t heirshades also depend onthe climatic zone.

Insulation helps reduceheat gain into, and heatloss from, a building.Double glazed windowswith air gaps can act asgood insulation. Theinsulating air gap lowersthe heat gain of thebuilding. It should beused for air-conditionedspaces. BEE (Bureau of

Energy Efficiency) has9 9

recommended specificationsfor glazing in air-conditioneds p a c e s , i n t h e E n e r g yConservation Building Code2007 (www.bee-nic.in)

Insulation can be added to

walls or roofs to reduceheat transfer. It also helpsin moderating indoorthermal comfort and iseffective in reducingtemperature fluctuationsin non air-conditioned spaces. Some commonly usedinsulation materials are mineral wool, extruded/expanded polystyrene, PUF (polyurethane foam),and vermiculite, among others. Since roofs receivemaximum solar radiation, it is advisable to insulate themusing any of the above materials. Cavity walls are an

effective method of insulation. Fly ash-based aeratedconcrete blocks and cellular concrete blocks have goodinsulating properties and can be used for wall insulation.Suitable specifications can be provided by anarchitect depending on the climatic zone where thebuilding is to be constructed.

Building insulation

4

Sunshades reduce the directsolar radiation entering

the house.

Sunshades

Window design

The sizes of windows andtheir shades also depend onthe climatic zone.

Air or

inert gas

Inside

020 C00 C

Outside

Low-emissivity

coating

Double glazed windows

How a double glazedwindow works

Construction details(L to R) forinsulation, waterproofing,air-conditioning ducts, serviceducts underside the shadingelements, window frames andelectrical box protection


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Roof treatment

Evaporative cooling

Landscaping

Some simple roof treatments, other thanroof insulation, for reducing the summerheat gain in buildings, are as follows.

White washing the roof before theonset of the summer.

Spraying water on the roof. Sprinklingwater at regular intervals can reduceheat gain through roof.

Using shining and reflecting material for therooftop.

When water stored in a waterbody evaporates into thesurrounding air, it lowers theambient temperature. Thisphenomenon is known as

e v a p o r a t i v e c o o l i n g . T h epresence of a water body such asa pond, lake or sea near thebuilding or even a fountain in thecourtyard can provide thec o o l ing effec t . T he m o s tcommonly used system is adesert cooler, which compriseswater, evaporating pads, a fan, and a pump. Externalcooling through humidification can also be achieved bykeeping surfaces of roofs moist using sprays or lawnsprinklers. Evaporative cooling is very effective in the hot

and dry climatic zone, where humidity is low.

Landscaping provides a buffer againstheat, sun, noise, traffic, and airflow. It isalso effective in diverting airflow orexchanging heat in a solar-passive design.Deciduous trees, such as amaltas, champa,and similar varieties, provide shade in thesummer and sunlight in the winter whentheir leaves fall. So planting such trees tothe west and south-west of a building is anatural solar passive strategy. Evergreen

trees provide shade and wind control round the year.They are best placed to the north and north-west of abuilding. Natural cooling, without air-conditioning, canalso be enhanced by planting trees to channelsouth-easterly summer breezes in tropical climates. Hardsurfaces and dark coloured pavings such as concretepavements or cement concrete pathways around a houseshould be avoided because it may increase the

surrounding temperature. Increased temperature wouldresult in thermal discomfort inside the house andincrease air-conditioning bills. Instead, soft surfaces suchas organic paving or vegetated areas should be used.

A compact building gains less heat during daytime andloses less heat at night. The compactness of the buildingis the ratio of its surface area to its volume, that is,Compactness = S/V (surface area/volume). In hot-dryclimates the S/V ratio should be as low as possible tominimize heat gain. In warm humid climates the prime

concern is creating airy spaces. This would require ahigher S/V ratio.

In places in cold climatic zones, for example Shimla,where temperatures outside are lower than they areinside, heat flows away from buildings through theirexternal envelopes and due to air exchange. In suchclimates, passive heating measures are adopted toprovide thermal comfort and also to reduce the demandfor conventional heating. Two methods are popular forpassive heating of buildings.

Direct gain methodIt is the simplest, cheapest, mostc o m m o n , y e t e f f e c t i v eapproach for heating theinteriors of a building. Sunlightis permitted into habitablespaces through an opening,which allows it to directly strikeand heat the floor, walls orother internal objects. These, inturn, heat the air within theroom. Double glazed windows

face the south (in the northern

Surface to volume ratio

Passive heating

Trees reduce ambient airtemperatures and cool thesurrounding areas.

Water moderates harshambient conditions around

the building

Direct gain method

Insulate the roof with materialssuch as rock wool, mineralwool, EPS, XPS, vermiculite,and so on.


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hemisphere) to receive maximum sunlight in winter.During the night, these windows act as insulatingcurtains and prevent heat loss. In addition, during theday, when areas of the building exposed directly tosunlight tend to over-heat, high thermal mass absorbsand stores heat in bare massive walls or floors and arreststhe increase in room temperature. Heat stored in themass is then released into the interior during the night,

when the temperature falls, keeping the room suitablywarm. Some examples of thermal storage materials areconcrete, bricks, stone, and water, which are usuallylocated in internal or external walls, floors and otherbuilt-in structures that receive sunlight directly.

Indirect gain method In this strategy, a thermal storagewall is placed between the glazing and habitablespace. This prevents solar radiation from directlyentering the living space. It is absorbed, stored, andthen, indirectly transferred to the habitable space. Atrombe wall is a thick solid wall with vents at its lower

and upper ends. It is usually painted black or a darkcolour to increase its heat absorption capacity. Thiswall is placed directly behind the glazing with an airgap in between. The vents act as inlets of warm airinto the room and as outlets for flushing out cool airfrom the room. The air in the space between the

glazing gets heated and enters the habitable roomthrough the upper vents.

At a depth of 4 m below ground, the earthstemperature remains more or less constant

throughout the year. This temperature is nearlyequal to average temperature of the place.For example in Delhi, the temperature insummer may go up to 45 C during summer andfall to 4 C during winter, but at a depth of 4 mbelow ground the temperature remains nearly26 C round the year, which is averagetemperature of Delhi. The earth air tunnel takes

advantage of this phenomenon. Concrete humepipes are laid at a depth of 4 m below ground and

are surrounded by earth. The earth acts as a heatexchanger for air that is passed through this tunnel. Hot

summer air is passed through this buried pipe, and as it

Earth air tunnel

passes through, there is an exchange of heat between theair and the surrounding earth. Hence, during the summer,the air gets cooled and during winter it gets heated. Itworks in a similar manner during the winter, absorbing

earths heat and releasing it into the structure. Tunnel aircan be supplied to a house for cooling during summersand heating during winters.

Solar chimneys are tall, hollow structures that arepreferably located on the south/south-west portion of abuilding. These chimneys can help ventilate rooms andare ideal for hot climatic zones. They should, preferably, bedark in colour with lightweight construction (for instance,ferrocement). Spaces within a building have ventsopening into this chimney. The chimney heats up during

summer days and the air inside the chimney rises creatinga low-pressure zone. The air from the rooms of the housethen replaces the escaping chimney air creating alow-pressure zone inside your home. This makes way foroutside air to enter the home naturally and cool it.

Wind towers are specifically designed to use prevailingwind to draw air out of a space and, sometimes, to push airinto the space. This helps circulate cool air in the building.When hot ambient air enters the tower through openingsin it, it cools, becomes heavier and sinks. Inlets and outlets

in rooms induce cool air movement. In the presence of

Solar chimney

Wind tower

To catch favourablecool wind from the

south-west forpassive cooling

Earth air tunnel systems canbe used for passive spaceconditioning

Indirect gain method

Wind towerFor effectiveventilation, speciallyduring humid weather

Solar chimney


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wind, air is cooled more effectively and flows faster downthe tower and into the living area. After a whole day of airexchanges, the tower becomes warm in the evening.During the night, cooler ambient air comes in contactwith the bottom of the tower through the rooms. Thetower walls absorb heat during the daytime and release itat night, warming the cool night air in the tower. Warm airmoves up creating an upward draft and draws cool night

air through the doors and windows into the building. Thesystem works effectively in hot and dry types of climatewhere diurnal variations are high.

As mentioned earlier, buildings in different climatic zonesrequire different passive features to make structuresenergy-efficient. Some features that can be adopted in

particular zones are listed below.

Appropriate orientation and shape of building Insulation of building envelope Massive structure Air locks, lobbies, balconies, and verandahs Weather stripping and scheduling air changes Externalsurfacesprotectedbyoverhangs,fins,andtrees Pale colours and glazed china mosaic tiles Windows and exhausts Courtyards, wind towers, and arrangement of openings Trees, ponds, and evaporative cooling

Appropriate orientation and shape of building Roof insulation and wall insulation Reflective surface of roof Balconies and verandahs Wallsglasssurfaceprotectedbyoverhangs,fins,andtrees Pale colours and glazed china mosaic tiles Windows and exhausts Ventilated roof construction, courtyards, wind towers,

and arrangement of openings Dehumidifiers and desiccant cooling

APPLICABLE PASSIVE FEATURES FOR VARIOUS

CLIMATIC ZONES

Hot and dry

Warm and humid

Moderate

Cold

Composite

Appropriate orientation and shape of building Roof insulation and east and west wall insulation Walls facing east and west, glass surface protected by

overhangs, fins, and trees Pale colours and glazed china mosaic tiles Windows and exhausts Courtyards and arrangement of openings

Appropriate orientation and shape of building Use of trees as wind barriers Roof insulation, wall insulation, and double glazing Thicker walls Air locks and lobbies Weather stripping Darker colours Sun spaces, greenhouses and trombe walls

Appropriate orientation and shape of building Use of trees as wind barriers Roof insulation and wall insulation Thicker walls Air locks and balconies Weather stripping Walls, glass surfaces protected by overhangs, fins, and

trees Pale colours and glazed china mosaic tiles Exhausts Courtyards, wind towers, and arrangement of openings

Trees and ponds for evaporative cooling Dehumidifiers and desiccant cooling

Lighting in a home is generally responsible for 20% of theelectricity bill.

Efficient lighting reduces energy consumption, thereby,saving energy and money, without compromising on thequality of light. Lighting improvements are the surest way

of cutting energy bills. Using new lighting technologies

ENERGY-EFFICIENT LIGHTING

1 0 1 1


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1 3

can reduce energy use in the house by 50% to 75%.Lighting controls offer further energy savings by reducingthe amount of time that lights are on without being used.

Use fluorescent tubelights and energy-efficient CFLs (compact fluorescent lights)in fixtures at home for high-quality and

high-efficiency lighting. Fluorescent lampsare much more efficient than incandescent(standard) bulbs and last up to six timeslonger. Although fluorescent and compactfluorescent lamps cost a bit more thanincandescent bulbs, they pay forthemselves by saving energy overtheir lifetime.

A 15 W CFL can replace a 60 W incandescentbulb and a 20 W CFL can replace 100 W bulb.

The average cost of a CFL is Rs 100, and the

excess investment is easily paid back in ayears time. A 36 W triphosphor tubelight,provides 32% more light than an ordinarytubelight and can be used in larger spaces.

T5 tubelights are good replacements forordinary tubelights. They save about 40% energy and lasttwice as long as ordinary tubelights. The cost of a T5tubelight varies between Rs 450 and Rs 500.

Many homeowners use outdoor lighting fordecoration or security.

Consider PV-powered lightsfor areas that are not closeto an existing power supplyline. Solar outdoor lightsalso come as stand-alonefixtures. An 11 W CFL, with a74 W photovoltaic moduleand a 12 V/75 AH battery,costs Rs 22 00024 000.When fully charged, thebattery can power a lightfrom dusk to dawn.

Indoor lighting

Outdoor lighting

ENERGY-EFFICIENT AIR CONDITIONERS

ACs (air conditioners) are used to cool or heat a room andusually consume the highest energy among all homeappliances. Window ACs and split ACs are mostcommonly used. These are available in different sizes0.75 tonne, 1 tonne, 1.5 tonne, and 2 tonne. Insulation ofthe walls, roof, and efficient windows in the room would

allow you to pick an AC with lesser tonnage.

The energy consumption ofan AC depends on the sizeof the AC. Therefore, selectan AC that suits yourrequirements. A 1-tonne ACis appropriate for a 150 sq ftroom, while 2-tonne AC issufficient for a room, whichis 300 sq ft in area.

The efficiency of an AC affects energy consumption asmuch as the size of the AC does. Select an efficient AC,preferably one that has a BEE Star label. The number ofstars on the BEE label indicates the efficiency of an AC;the higher the number of stars the more efficient theappliance. For instance, a BEE 4-star rated 1.5-tonne ACwould consume 194 units of electricity in a monthcompared to an inefficient AC of the same size thatwould consume 278 units during the same period. Anefficient 1.5-tonne AC would cost about Rs 16 500,

whereas an ordinary AC would cost about Rs 15 000.The additional Rs 1500 invested on the efficient AC willbe recovered in less than six months due to savings in theelectricity bill. In case of the non-availability of the BEEstar label, check the EER (energy efficiency ratio)mentioned on the AC. An EER of 8 is equivalent to a 1-starBEE label and an EER of 10.6 and above is equivalent to5-star BEE label.

While installing an AC, ensure that the exterior (or back) ofthe AC is not exposed to direct sunlight and is away fromheat sources such as chimneys. Efficient airflow across the

Selecting the right size

Selecting an efficient AC

Installing an AC

Outdoor lights can be poweredby small PV (photovoltaic)modules that convert sunlightdirectly into electricity.


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1 4 1 5

exterior would ensure efficient operation of the AC. Sealdoors and windows properly to make sure that air doesnot escape through them. This would help in reducingenergy consumption.

A solar water heater is a device that uses heat energy ofthe sun to provide hot water for various applications. Inhomes, it is useful for bathing, washing, cleaning, and

other chores. A domestic solar water heater, with acapacity of 100 lpd (litres per day), is sufficient for a familyof four or five members. It can easily replace a2-kW electric geyser and can save up to 1500 units ofelectricity a year. It pays back the cost in three to five yearsdepending on the electricity tariff and hot water use in ayear. After this, hot water is available almost free of cost

during remaining lifespan of the system, which is about15-20 years.

The system is generally installed on the terrace andrequires minimum maintenance. It works automaticallyand one does not have to operate any part of the system.

Typically, a surface area of 3 sq m is required to install it. The system can also be installed on a south-facingwindowsill if space is not available on the terrace.

Two types of systems are being promotedone based onFPC (flat plat collectors) and the other on ETC (evacuatedtube collectors). The life of FPC-based systems is generally

RENEWABLE ENERGY DEVICES/SYSTEMS

Solar water heating system

1520 years, and they are costlier than ETC-basedsystems. There are 57 BIS (Bureau of Indian Standards)-approved manufacturers of these systems, and they havehad a stable market in the country for the last many years.

ETC-based systems are relatively new and couldbe more reliable for colder regions and regions

that have hard water. The life of these systems is, however,less since their collectors comprise glass tubes, which arefragile. There are 29 suppliers of these systems approvedby the MNRE. The list of manufacturers and suppliers isavailable at the Ministrys website ( www.mnre.gov.in).

The cost of solar water heaters, with a capacity of 100 lpdvaries between Rs 18 000 and Rs 25 000. To offset theinitial high price, loans at 2% are offered to users throughbanks/financial institutions. The list of such banks/financial institutions is available on the Ministrys website.In addition, some state governments also provide state

subsidy. For example, Delhi Transco Ltd offers Rs 6000 asrebate on installation of the system. A few governmentsalso provide rebate in property tax and in electricity tariffif a solar water heater has been installed at home. Detailsare available on the Ministrys website.

The installation of a solar water heating system in ahome/building needs to be planned at the time of itsconstruction. The following points may be kept in mindwhile planning for the same.

i) A 3-4 sq m (per 100 lpd system) shadow-free areashould be available on the terrace for installation.

Flat plate collectors-basedsolar water heater

Evacuated tubecollectors-based solarwater heater


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ii) Provision for concealed PER pipes, with requiredinsulation for installation of the system, should be

made at the design andconstruction stage of homes/buildings.

A number of builders anddevelopers have alreadystarted constructing housesand apartment blocks, whichare fitted with solar waterheating systems. An example isMagarpatta City, where a largenumber of such housing andoffice complexes have comeup on the outskirts of Pune.

A PV system can be incorporated in a building as part of

the building's structure. In new buildings, PV systems canbe built-in at the design and construction stage. They canbe retrofitted on existing buildings as well. Photovoltaicscan be integrated in every possible structurefrom bus

shelters to high-rise buildings. They can also be used aslandscaping elements.

Incorporating PV in a buildingresults in the following valueadditions.

Generating electricity at the

point of demand withoutany extra use of land area

Reducing the cooling loadof the building, as it alsoacts like a shading element

Replacing building construction material, such asglazing elements, depending on the building design

In building integrated PV systems, PV modules are used aspart of the building envelope. PV systems can beincorporated in a building in three basic ways.

Building integrated PV system

Faade-integrated photovoltaic systems Curtain walls,semitransparent PV windows, PV awnings, and so on

Roof-integrated photovoltaic systems Atrium roofs, flatand tilted roofs, skylights, tiles, and slates among othermaterials

Shadow-Voltaic PV systems that can be used asshadowing systems

There are various other renewable energy devices/systems, such as solar cookers, solar lanterns, solar homesystems, and solar inverters, which can be used forsaving conventional energy after the home/buildingis constructed. Details of these devices are available onMNRE website (www.mnre.gov.in).

Other renewable energy devices/systems

Systems integrated withbuildings in Magarpatta City

A BiPV system


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ANNEXURE

List of architects/experts/institutes/organizationswith experience in designing energy-efficienthomes/buildings

Architects / experts

Amit Kembhavi, DSP Design Associates Pvt. Ltd, ArchitectsInterior Designers, 5th Floor, Rahimtoola House

7, Homji Street, Fort, Mumbai 400 001

Anamika Prasad, Environmental Design Solutions522 Pocket C, Sector A, Vasant Kunj, New Delhi 110 070E-mail: [email protected]

Anant Mann and Siddhartha Wig, The Elements279 Sector 6, Panchkula 134 101

Arvind Krishan, Former Head - Deptt of Architecture, SPACentre for Architectural Systems AlternativesB-4/103 Safdurjung Enclave, New Delhi 110 029

Ashok B Lall, 2B , Ramkishore Road, Civil LinesNew Delhi 110 054

Ashutosh Kr Agarwal, 202, 2nd floor, A-2, Acharya NiketanMayur Vihar, Phase I, New Delhi 110 091

B K Tanuja, Partner, Kanvinde Rai & Chowdhury14-F Middle Circle, Connaught Place, New Delhi 110 001

Balakrishna Doshi, Vastu-shilpa Foundation for Studies &Research in Environmental Design, Sangath Thaltej RoadAhmedabad 380 054

C N Raghavendran, Partner C R Narayana Rao5 Karpagambal Nagar, Chennai 600 004E-mail: [email protected]

Christopher Charles Benninger Architects Pvt. Ltd

Shraddha 1 Samata Society, Ashok Nagar, Near BhosaleNagar Gate, Off University Road, Pune 411 007Maharastra, India

DSP Design Associates Pvt. Ltd, No. 60, 2nd laneAnand Park, Aundh, Pune 411 007

Gerard Da Cunha, Architecture AutonomousHouse No. 674, Torda, Salvador do-Mundo, BardezGoa 403 101; E-mail- [email protected]

Indranil Roy, Architects I Roy & AssociatesK 1/80 Basement, CR Park, New Delhi 110 019E-mail: [email protected]

Jaisim Fountainhead , 175/1, Pavilion Road, 1 Block EastJayanagar, Bangalore 560 011

Jayprakash Agrawal, Agrawal & Agrawal, 98 Beltala Road1st Floor, Kolkata

Mani Chowfla , Architects, D 374 Defence ColonyNew Delhi 110 024

Nalini Kembhavi, Kembhavi Architecture FoundationAugust House, Plot No. 40, Behind Pai Hotel

Bailappanavar Nagar, Hubli 580 029E-mail: [email protected]

Nimish Patel, Abhikram, 15 Laxmi Niwas Society, PaldiAhmedabad 380 007

Nisha Mathew, Soumitro Ghosh, Mathew & GhoshArchitects, 2 Temple Trees Row, Vivek Nagar P.O.Bangalore 560 047

Prasoon Shrivastava, Architect, R K & Associates1846/1 Silver Oak Compound, Napier Town, Jabalpur

Pravin Patel, A-13, Aditya Complex, Opp. TelevisionStation, Off Drive in Cinema Road, Ahmedabad 380 054

Rahul Kumar, Rajinder Kumar and AssociatesB-6/17, Shopping Centre, Safdarjung Enclave, New DelhiE-mail: [email protected]

Roopmathi Anand, Rajendran Associates58 SS Road, Alwarpet, Chennai 600 018E-mail: [email protected]

Sanjay Mohe, Director, MINDSPACE, 408, 12th MainRMV Extension, Sadashivnagar, Bangalore 560 080

Sanjay Prakash, Sanjay Prakash & AssociatesR1/301 Hauz Khas Enclave, New Delhi 110 016

Sen Kapadia, 104, Oyster Shell, Juhu Beach

Mumbai 400 049Sharukh Mistry, Mistry Architects, 444,13th Cross, 5thMain, 2nd Stage, Indiranagar, Bangalore 560 038E-mail: [email protected]

Stephan Paumier & AssociatesKhirki Extension Malaviya Nagar, New Delhi

Suhasini Ayer Guigan, Auroville Building CentreAuroshilpam, Auroville 605 101

Vinod Gupta, Space Design ConsultantsK-38, Jungpura Extension, New Delhi 110 014

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Vidur Bhardwaj, Consultant Architect, Design &Development Architects, Engineers & Interior DesignersC 58 Defence Colony, New Delhi 110 024E-mail: [email protected] / [email protected]

Vineeta Badawe, Director, V V Architects Pvt. Ltd6 Kilpauk Garden Road, 1st Street , KilpaukChennai 600 010E-mail: [email protected]

Institutes/Organizations

Gherzi Eastern Ltd16, Mahanirban Road, Kolkata 700 029

Ghosh Bose and Associates Pvt. Ltd8, Harrington Mansion, 8, Ho Chi Minh SaraniKolkata 700 071

HUDCOIndia Habitat Centre, Lodhi RoadNew Delhi 110 003

Himachal Pradesh State Council for Science Technology

and Environment,B-34, SDA Complex, KasumptiShimla 171 009

Solar Energy CentreMinistry of New and Renewable Energy, Gual PahariGurgaon District, Haryana

TERIDarbari Seth Block, IHC Complex, Lodhi RoadNew Delhi 110 003

Available on the MNRE website: www.mnre.gov.in

Available on the MNRE website: www.mnre.gov.in

List of State Nodal Agencies for new and

renewable energy

List of manufacturers of solar energy systems

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Energy Efficient Solar Homes Buildings

Documents