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-YASH JHAWAR

B.ARCH (Xth SEM)

P.I.A.D.S.

PASSIVE

DESIGN

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y INTRODUCTION:

y Almost all houses and buildings in India are designed in a manner that theyrequire artificial sources of heating or cooling. These houses are energy

inefficient, too cold or too hot and comparatively expensive to run.Similarly, most homes use far more water than necessary, and are made ofmaterials that can damage health and the environment. Building a homeusing good design principles can save energy, water and money, whilecreating a more enjoyable and comfortable home.

Passive cooling systems are least expensive means of cooling a home

which maximizes the efficiency of the building envelope without any useof mechanical devices.

It rely on natural heat-sinks to remove heat from the building. Theyderive cooling directly from evaporation, convection, and radiation withoutusing any intermediate electrical devices.

All passive cooling strategies rely on daily changes in temperature and

relative humidity. The applicability of each system depends on the climatic conditions.

These design strategies reduce heat gains to internal space.

Using passive design will make our environment pollution free and

y peaceful to leave in.

YASH JHAWAR B.ARCH (X SEM) P.I.A.D.S

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y AIM: To study the advantages of passively designed houses. To study themethods of applying passive design techniques in a house or a building.

y OBJECTIVES:

y To study the importance of Passive design in houses and buildings.

y The objective will be to try and study the methods of applying passiveheating and cooling techniques while designing.

y To study use of passive designing in reducing energy consumption.

y SCOPE: The scope of the study is to study the actual designing of housesand buildings using passive designing. Passive designing relates to usingenvironmental elements to be useful to a house rather than using of anartificial system. Passive designing takes into account thermal comfort. Itallows designing in such a manner that the house needs minimum external

temperature regulators.

y LIMITATION: Lack of awareness about the increasing greenhouse effects,the emission of CFC and harmful gases. The high cost of developing asustainable design, and requirement of high cost materials in buildings.


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WHY TO USE PASSIVE DESIGN?

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y According to Research,

38% of the total energy

required by a house is used

up in heating or cooling the

house.

y Using passive design can

greatly reduce this.


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PASSIVE COOLING

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The main elements of design forpassive cooling are:

y Orientation for exposure tocooling breezes.

y Increase natural ventilation byreducing barriers to air pathsthrough the building.

y Provision of fans to provideventilation and air movement

in the absence of breezes.y Provide paths for warm air to

exit the building.


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METHODS TO ACHIEVE PASSIVE DESIGN

1.ORIENTATION

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y A home that is well positioned on its site deliverssignificant lifestyle and environmental benefits.Correct orientation assists passive heating andcooling, resulting in improved comfort anddecreased energy bills.

y In hot humid climates and hot dry climates withno winter heating requirements, orientation shouldaim to exclude sun year round and maximizeexposure to cooling breezes. It involves lettingwinter sun in and keeping unwanted summer

sun out.y This can be done with relative ease on northern

elevations by using shading devices to excludehigh angle summer sun and admit low anglewinter sun.


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2.SHADING

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y Shading of the building and outdoor spaces reduces

summer temperatures, improves comfort and saves

energy. Shading can block up to 90 percent of the

direct sun light.

y Use plants to shade the building, particularly

windows, to reduce unwanted glare and heat gain.

y With ideal north orientation sun can be

excluded in summer and admitted in winter using

simple horizontal devices, including eaves.


Can use overhangs on outside

facade of the building.

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3.PASSIVE COOLING BY AIRMOVEMENT

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y Air movement increases cooling byincreasing evaporation rates.

y Generally, cross ventilation is mosteffective for air exchange (buildingcooling) and fans for air movement(people cooling).

y An air speed of 0.5m persecond equates to a 3 degreedrop in temperature atrelative humidity of 50 percent.

y

In higher humidity, greaterairspeeds are required to achievethe same cooling benefits.

y Maximizing the flow of coolingbreezes through a home is anessential component of passive

design. YASH JHAWAR B.ARCH (X SEM) P.I.A.D.S

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In a wind tower, the hot air enters the tower through the

openings in the tower, gets cooled, and thus becomesheavier and sinks down.

The inlet and outlet of rooms induce cool air movement.

In the presence of wind, air is cooled more effectively

and flows faster down the tower and into the living area.

After a whole day of air exchanges, the tower becomeswarm in the evenings.

During the night, cooler ambient air comes in contact

with the bottom of the tower through the rooms.

4.WIND TOWER

Wind tower inJodhpur Hostel to

catch favorable cool wind from south-

west for passive cooling

Building-integrated chimney in a residence in

New Delhi


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5.EVAPORATIVE COOLING

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y Large amounts of heat are consumed bywater as it evaporates.This is called the

latent heat of evaporation.This heat is

partially drawn from surrounding air,

causing cooling.

y Evaporation is an effective passivecooling method.

y Evaporative cooling lowers indoor air

temperature by evaporating water. It is

effective in hot and dry climate where

the atmospheric humidity is low.The

presence of a water body such as a pond,

lake, and sea near the building or a

fountain in a courtyard can provide a

cooling effect.


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6.PASSIVE DOWN DRAUGHT COOLING

Evaporative cooling has been used for many

centuries in parts of the middle east, notablyIran and turkey.

In this system, wind catchers guide outside air

over water-filled pots, inducing evaporation and

causing a significant drop in temperature beforethe air enters the interior.

Such wind catchers become primary elements

of the architectural form also.

Passive downdraught evaporative cooling isparticularly effective in hot and dry climates. It

has been used to effectively cool the Torrent

Research Centre in Ahmedabad.

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6.INSULATION

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y Insulation acts as a barrier to heatflow and is essential to keep your

home warm in winter and cool in

summer.

y A well insulated and well designed

home will provide year-roundcomfort and will reduce

greenhouse gas emissions.

TYPICAL HEAT GAINSAND LOSSES

INATEMPERATE CLIMATE.YASH JHAWAR B.ARCH (X SEM) P.I.A.D.S

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7.THERMALMASS

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y Thermal mass is the ability of a material to absorb heatenergy. A lot of heat energy is required to change the

temperature of high density materials like concrete,

bricks and tiles.They are therefore said to have high

thermal mass. Lightweight materials such as timber

have low thermal mass.

y Externally insulated, dense materials like concrete,

bricks and other masonry are used in passive design to

absorb, store and re-release thermal energy.

y This moderates internal temperatures by averaging

day/night (diurnal) extremes, therefore increasing

comfort and reducing energy costs.


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y With a near consistent 8% rise in annual energy consumption in the

residential and commercial sectors, overall energy consumption in buildingshas seen an increase from a low of 14% in the 1970s to nearly 33% in

2004/05.

y T

his is directly related to higher greenhouse gas emissions.T

hus, it is theneed of the hour to design and construct High Performance Energy Efficient

Buildings.

y To fulfill this objective,TERI, in association with BEE (Bureau of Energy

Efficiency), Ministry of Power, Government of India, and White BoxTechnologies, USA, has undertaken a project 'High Performance

Commercial Buildings in India' to make commercial buildings in India energy

efficient.


CASE STUDY

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1.Solar Passive Design Building,

Transport Corporation of IndiaLtd (TCIL), Gurgaon

General Information:

y City: Gurgaon

y Climate: Composite

y Operational schedule 6 days and 12 hours

y Area of the building: 3058m(out of which2607 m- conditioned area, 451 m- Non-conditioned area)

Energy Performance Index of the building(KWh/sq.mts of built up area/annum):147as against 170 of the conventionalbuilding


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y Orientation: NE, SWThis helps in receiving less radiation

which results in lesser heat gains and

reduced the overall air-conditioning

requirement and hence saves energy.

Proper orientation also helps in

receiving natural light and ventilation

y Minimum height above the ground

level to limit exposure to external

conditions. Recessed windows to

reduce external solar heat gains.


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y Fountain to flow over extensive

surfaces to maximize evaporation.

Water evaporation has a cooling

effect in the surroundings.

y WALLS: Insulation helps retain

cool in summer and heat in winter,

and acts as sound proof.This can

create a major impact on indoor

thermal comfort of the building.


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y WINDOWSy Single glaze recessed windows

y Single glazed unit helps in integratingoptimum daylight

y Recessed windows and optimum WWR(Window Wall Ratio) which is less thanECBC standard (40%) helps in reducing

external solar heat gain

y

ROOFSy 35 mm thickness insulation with

reflective glazed tile paving

U-value = 1.01 W/m2K

y The glazed tile reflects heat off thesurface because of the high solarreflectivity and infrared emittance whichprevents heat gain and thus helps inreducing the cooling load from thebuilding envelope.


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y Window area minimized to 14%of the external wall area, smallpeep windows at seating heightand large windows at ceilinglevel

y

Small windows at the seatingareas can reduce thermaldiscomfort.The reduced percentage ofwindow area to wall area helpsin reducing the external heatgain into the building.

y 9% (18.10 KW of indoorlighting) of the total connectedload for the building.Luminaires used down lighterrecessed type CFLs, electronic

ballasts used mostly.LPD 5.9 W/m2

y The percentage of the lightingload to the total load shows thatthere is very less percentage ofartificial lighting used in the

building

y The electronic ballasts saveapprox 20-30% in energyconsumption over the standard

ballasts.


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2. Solar Passive Design Building, Dr. Reddys Lab.Ltd- IPDO - Innovation Plaza, Hyderabad

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y General Information:

Client: Dr. Reddyslaboratories Ltd- IPDO -

Innovation PlazaCity: HyderabadClimate: Hot & DryOperational schedule8h 30 min, 5 working days

a weekArea of the building:25, 682.6m


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y ORIENTATION:

y The longer faade on N-Sorientation and least

exposure on west helped toreduce the solar heat gainsin this hot climate region

y The store and wash Buffer

areas act against intensesolar radiation


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y Existing landscape preservedand integrated with the builtspaces

y The built areas are integratedwith lot of greenery and water

bodies Roof A, B and C haveskylights made fromtranslucent asbestos sheet

y Existing landscape preserved

with the built spaces makes allworking areas as naturallyventilated areas which do notrequire any air conditioning.

y The reception areas as well asresearch building blocks are

surrounded by water bodies,major modifiers of micro-climate which helps inmaintaining thermallycomfortable circulation areasand semi-open areas.


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y

Service areas along externalwalls act as buffer zone andpreventexternal conduction gain,thereby reducing the coolingload of the building

Single glazed blue grey 6mmwindows

Tinted glass with shading on all

windows helps

in reducing solar heat gain and

also the problem of glare.


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y Natural day light integration

through skylights in all the spaces

between the labs and circulation

areas which makes the spacesrequire no artificial light during day

time

y Inner glass partitions also help

integrate daylight for outside

circulation areas.

Energy Performance Index of the building

(KWh/sq.mts of built up area/annum): 131

As compared to199

earlier.


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THANK YOU!

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passive design(06-01-2011)

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