Solar Buildings

8/12/2019 Solar Buildings

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PASSIVE SOLAR BUILDING

2013-14

ABSTRACT

Houses generally refer to a shelter or building that is meant as a dwelling or place for

habitation by human beings. Houses include many inds of dwelling ranging from

rudimentary huts or nomadic tribes to high!rise apartment buildings.

A ma"or constraint in meeting this demand is the spiraling cost of energy and other

changes in climate. Passive solar buildingsaim to maintain interior thermal comfort

throughout the sun#s daily and annual cycles whilst reducing the re$uirement for acti%e

heating and cooling system &assi%e solar building design is one part of green building

design' The scientific basis for passi%e solar building design has been de%eloped from a

combination of climatology' thermodynamics (particularly heat transfer)' and human

thermal comfort (for buildings to be inhabited by humans). Specific attention is directed

to the site and location of the dwelling' the pre%ailing climate' design and construction'

solar orientation' placement of gla*ing!and!shading elements' and incorporation of

thermal mass. +hile these considerations may be directed to any building' achie%ing an

ideal solution re$uires careful integration of these principles.

They present seminar intends to discuss

,emand for &assi%e solar building design.

-nterior thermal comfort

nergy sa%ings in the in future by fallowing passi%e building

design.

/rientation of building according to solar path

&assi%e solar heating strategies 0 relati%e design method.

n%ironment 1 friendly' energy!efficient technologie

,epartment /f Ci%il ngg' R23C' B44AR2 Page 1


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CONTENTS

5. -ntroduction 6

7. History 8

7.5 &re 3odern History

7.7 arly &assi%e Solar ,esign

7.9 3odern History

9. Components :

9.5 Collection

9.7 Storage

9.9 ,istribution

9.6 Control

6. Solar &ath -n &assi%e ,esign 55

;. &assi%e solar building design principles 59

;.5 /rientation

;.7 /%erhangs and Shading

;.9 +indows

;.6 Thermal mass8. &assi%e Solar Building ,esign Concepts 7. /ther Considerations 98

?. Conclusions 9:

:. References 6. Thermal mass in the interior absorbs 7< degrees' balancing the s$uare footage of glass (solar collectors) and the right amount

of effecti%e thermal storage mass.

-n winter' thermal mass absorbs heat by direct sunlight. At night the process is re%ersed

as thermal mass gi%es up heat' warming the room

by radiation' con%ection and conduction. -n the summer' thermal mass should be shaded

so it draws the warmth from the surrounding air and cools the room. The greater the area

of thermal mass' the greater its ability to store heat and maintain a uniform temperature.

There are two ways thermal mass wors in a passi%e design homeE direct solar

gain and indirect solar gain.

How thermal mass is used in a passi%ely designed home is the owner#s choice. Thermal

mass can tae numerous forms such as bric' tile or thic concrete floors (called a Solar

Slab). -t can also be a large bric or stone internal fireplace or an interior wall made of

adobe or bric.

A masonry or concrete wall (called a Tro4be 3all) or water filled containers (called

a Tube 3all) can also be used to absorb heat and cool. This type of system must ha%e

southern eposure and recei%e direct sunlight.

Regardless of which type of passi%e system is installed in your home' it must be

thoughtfully designed' balancing gla*ing with thermal storage mass.



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Chapter.8

Passive Solar 0uilding Design Con-epts .

A total of ele%en different passi%e concepts will be considered. 3any other possible solar

concepts were e%aluated. The ones listed below are appropriate in a wide range of

climates and building types.

(H) ,irect gain with storage

(H) -ndirect gain

(H) ,irect gain (without storage)

(H) Sunspaces

(C) ight 3echanical Dentilation

(C) atural Dentilation

(4) +indows



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(4) Sylights

(4) Sawtooth Apertures

(4) 3onitor Apertures

(4) AtriaThe letters (H)' (C)' and (4) stand for heating' cooling' and lighting' respecti%ely' and are

used to remind you of the purpose for each passi%e solar system concept.

5! Dire-t (ain

-n this system' the actual li%ing space is a solar collector' heat absorber and

distribution system. South facing glass admits solar energy into the house where it

stries directly and indirectly thermal mass materials in the house such as masonry

floors and walls. The direct gain system will utili*e 8< ! >;M of the sun#s energy

striing the windows.

@ig.>E Thermal mass in the interior absorbs the sunlight and radiates the heat at night

-n a direct gain system' the thermal mass floors and walls are functional parts of the

house. -t is also possible to use water containers inside the house to store heat. Howe%er'it is more difficult to integrate water storage containers in the design of the house.



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@ig.?E,irect =ain plus Storage.

Air ational =uard Composite /perations and Training @acility' Bangor' 3aine.

/TEThe illuminated mass wall on the left of the picture and the sloped direct gain

apertures in the roof.

Dire-t gain syste4 rules of tu4b.

A heat load analysis of the house should be conducted.

,o not eceed 8 inches of thicness in thermal mass materials.

,o not co%er thermal mass floors with wall to wall carpetingJ eep as bare as

functionally and aesthetically possible.

se a medium dar color for masonry floorsJ use light colors for other lightweight

wallsJ thermal mass walls can be any color.

@or e%ery s$uare foot of south glass' use 5;< pounds of masonry or 6 gallons of

water for thermal mass.

@ill the ca%ities of any concrete bloc used as thermal storage with concrete.



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se thermal mass at less thicness throughout the li%ing space rather than a

concentrated area of thicer mass.

The surface area of mass eposed to direct sunlight should be : times the area of

the gla*ing.

Sun tempering is the use of direct gain without added thermal mass. @or most

homes' multiply the house s$uare footage by


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@ig.5


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@ig.55E Thrombe wall

Thermal 3ass +alls or Trombe +all ,ay and ight /perable %ents at the top and

bottom of a thermal storage wall permit heat to con%ect from between the wall and the

glass into the li%ing space. +hen the %ents are closed at night radiant heat from the wall

heats the li%ing space.

Roof pond syste4s.

Si to twel%e inches of water are contained on a flat roof.

This system is best for cooling in low humidity climates but can be modified to wor in

high humidity climates. (ffecti%ely pro%ides heat in southern .S. latitudes during the

heating season for one story or upper stories of buildings.)

+ater is usually stored in large plastic or fiberglass containers co%ered by gla*ing and the

space below is warmed by radiant heat from the warm water abo%e.

These re$uire somewhat elaborate drainage systems' mo%able insulation to co%er and

unco%er the water at appropriate times' and a structural system to support up to 8; lbsLs$

ft dead load.



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Indire-t gain syste4 rules of tu4b for ter4al storage *alls

The eterior of the mass wall (toward the sun) should be a dar color.

se a minimum space of 6 inches between the thermal mass wall and the glass.

Dents used in a thermal mass wall must be closed at night.

A well insulated home (>!: BTLday!s$. ft.!degree @) will re$uire approimately

inches for concrete' ?!57 inches for adobe or other earth material and at least 8

inches for water.

5, Isolated (ain.

An isolated gain system has its integral parts separate from the main li%ing area of a

house. amples are a sunroom and a con%ecti%e loop through an air collector to a

storage system in the house. The ability to isolate the system from the primary li%ing

areas is the point of distinction for this type of system.

The isolated gain system will utili*e 5; ! 9


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collector naturally rises into the storage area and is replaced by return air from the lower

cooler section of the storage area. Heat can be released from the storage area either by

opening %ents that access the storage by mechanical means (fans)' or by conduction if the

storage is built into the house.

The sunroom has some ad%antages as an isolated gain approach in that it can pro%ide

additional usable space to the house and plants can be grown in it $uite effecti%ely.

The con%ecti%e air collector by comparison becomes more comple in trying to

achie%e additional functions from the system. This is a drawbac in this area where space

heating is less of a concern than in colder regions where the system would be used

longer. -t is best to use a system that pro%ides more than one function if the system is not

an integral part of the building. The sunroom approach will be emphasi*ed in this

information since it can pro%ide multiple functions.

@ig.57E ,ay and ight /peration of a Sunroom -solated =ain System



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Sunroo4s )Sunspa-e+.

Sunrooms can feature sloped andLor o%erhead glass' but is not recommended for the

Austin area. A sunroom will function ade$uately without o%erhead or sloped gla*ing.

,ue to long hot summers in this area' it is important to use ade$uate %entilation to let the

heat out. Sloped or o%erhead gla*ing is also a maintenance concern. ,ue to the intensity

of weather conditions for gla*ing facing the full .-. %entilationE passi%e design and brunt

of the sun and rain' seals between the ga*ing panels need to be of etremely high material

and installation $uality.

A thermal wall on the bac of the sunroom against the li%ing space will function lie

the indirect gain thermal mass wall. +ith a thermal wall in the sunroom' the etra heat

!,uring the day can be brought into the li%ing space %ia high and low %ents lie in the

indirect gain thermal wall.

3ore elaborate uses of the heated air generated in the sunspace can be designed into

this system' such as transferring the hot air into thermal mass located in another part of

the house.

Isolated (ain rules of tu4b for sunroo4s.

o

se a dar color for the thermal wall in a sunspace.o The thicness of the thermal wall should be ?!57 inches for adobe or earth

materials' 5

for each s$uare foot of li%ing space floor area. -f a water wall is used between the

sunroom and li%ing space instead of masonry' use


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6ig !,. sun spa-e

5/ Passive Solar Cooling.

7 'entilation 8 Operable 3indo*s

A primary strategy for cooling buildings without mechanical assistance (passi%e

cooling) in hot humid climates is to employ natural %entilation. (The @an and 4andscape

sections also address %entilation strategies.) -n the Austin area' pre%ailing summer

bree*es are from the south and southeast. This matches nicely with the increased gla*ing

on the south side needed for passi%e heating' maing it possible to achie%e helpful solar

gain and %entilation with the following strategiesE

&lace operable windows on the south eposure.

Casement windows offer the best airflow. Awning (or hopper) windows should be

fully opened or air will be directed to ceiling. Awning windows offer the best rain

protection and perform better than double hung windows.



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-f a room can ha%e windows on only one side' use two widely spaced windows

instead of one window.

7 3ing 3alls

+ing walls are %ertical solid panels placed alongside of windows perpendicular to the

wall on the windward side of the house.

@ig.56E Top Diew of +ing +alls Airflow &attern

+ing walls will accelerate the natural wind speed due to pressure differences created by

the wing wall

Ter4al Ci4ney

A thermal chimney employs con%ecti%e currents to draw air out of a building. By

creating a warm or hot *one with an eterior ehaust outlet' air can be drawn into the

house %entilating the structure.

Sunrooms can be designed to perform this function. The ecessi%e heat generated in a

south facing sunroom during the summer can be %ented at the top. +ith the connecting

lower %ents to the li%ing space open along with windows on the north side' air is drawn

through the li%ing space to be ehausted through the sunroom upper %ents. (The upper

%ents from the sunroom to the li%ing space and any side operable windows must be

closed and the thermal mass wall in the sunroom must be shaded.)



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@ig.5;E Summer Denting Sunroom

@ig.58E Summer Denting Thermal 3ass +all

Thermal mass indirect gain walls can be made to function similarly ecept that the

mass wall should be insulated on the inside when performing this function.



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@ig.5>E Thermal Chimney

Thermal chimneys can be constructed in a narrow configuration (lie a chimney) with an

easily heated blac metal absorber on the inside behind a gla*ed front that can reach high

temperatures and be insulated from the house. The chimney must terminate abo%e the

roof le%el. A rotating metal scoop at the top' which opens opposite' the wind will allow

heated air to ehaust without being o%ercome by the pre%ailing wind.

Thermal chimney effects can be integrated into the house with open stairwells and atria.

(This approach can be an aesthetic plus to the home as well.)

Oter 'entilation Strategies

3ae the outlet openings slightly larger than the inlet openings.

&lace the inlets at low to medium heights to pro%ide airflow at occupant le%els in

the room.



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@ig.5?E Thermal Chimney ffect Built into Home

-nlets close to a wall result in air FwashingF along the wall. Be certain to ha%e centrally

located inlets for air mo%ement in the center areas of the room.

+indow insect screens decrease the %elocity of slow bree*es more than stronger bree*es

(8


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51 Passive solar ligting.

S9yligts.

@ig.5:ESylight schematic.

Sylights (SI2)' as illustrated in @igure' are hori*ontal apertures cut through the roof of

a building.



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@ig.7


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story buildings that ha%e large open areas' such as industrial facilities' maintenance

facilities' and warehouses.

@ig.77E 3onitor aperture schematic.

$triu4.

AtriumE -n multistory commercial!type buildings' the most difficult location to daylight is

the center of the building' called the building core. An atrium (ATR) is a core daylighting

concept that opens up the center of the building so that it can he daylight. See @igure. An

atrium wors best when the perimeter of the building' within 5; ft of the eterior walls' is

daylighted using sidelighting techni$ues. An atrium can be capped with any of the roof

aperture systems pre%iously discussed.



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@ig.79E Atrium schematic

Chapter.>

Oter Consideration

Spe-ial (la:ing Syste4 8 3indo* Covering

The effecti%eness of direct solar gain systems is significantly enhanced by insulati%e

(e.g. double!gla*ing)' spectrally selecti%e gla*ing (low!e)' or mo%able window insulation

(window $uilts' bifold interior insulation shutters' shades' etc

=enerally' $uator!facing windows should not employ gla*ing coatings that inhibit solar

gain.

There is etensi%e use of super!insulated windows in the =erman passi%e house standard.

Selection of different spectrally selecti%e window coating depends on the ratio of heating

%ersus cooling degree!days for the design location.

(la:ing Sele-tion

E;uator 6a-ing (lass.



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The re$uirement for %ertical e$uator!facing glass is different than for the other three sides

of a building. Reflecti%e window coating and multiple panes of glass can reduce useful

solar gain. Howe%er' direct!gain systems are more dependent on double or triple coating

to reduce heat loss. -ndirect!gain and isolated!gain configurations may still be able to

function effecti%ely with only single!pane gla*ing. e%ertheless' the optimal cost!

effecti%e solution is both location and system dependent.

Roof#$ngle (lass < S9y %igt.

Sloping roof!angled glass is difficult to shade and insulate without sophisticated

mo%able systems. -n hot climates with significant degree day cooling re$uirements' it can

create a summer solar furnace (from the Ancient =ree L Roman term FheliocaminusF).

Roof!angled glass or sylights are not optimally placed to recei%e low!angled winter sun.

At the same time' they are the site of heat loss during winter from the buoyant warm air

that rises. As a result' they will increase heating and cooling energy re$uirements' which

ceeds the benefit of daylight energy consumption reduction compared to more energy!

efficient lighting systems such as light tubes.

Transparent glass and plastic ha%e little structural strength. Dertically' they bear their

own weight because only the thicness is sub"ect to gra%ity. As the angle tilts from

%ertical' an increased area (the sloped cross!section) must resist gra%ity. =lass is brittle !

-t does not fle much before breaing ! To counteract this' you must increase thicness'

or structural supports ! Both increase o%erall cost' and reduce solar gain potential. Sloped

gla*ing is eposed to the weather' leas' hail' ice!and!snow load' wind' and material

failure. cess solar gain' harsh lighting' and undesirable heat transfer through sloped

glass are difficult to control. Therefore' %ertical gla*ing is the o%erall best option for

sunspaces.

Operable Sading 8 Insulation Devi-es.



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A design with too much e$uator!facing glass can result in ecessi%e winter' spring' or

fall day heating' uncomfortably!bright li%ing spaces at certain times of the year' and

ecessi%e heat transfer on winter nights and summer days.

Although the sun is at the same altitude 8!wees before and after the solstice' the

heating and cooling re$uirements before and after the solstice are significantly different.

Heat storage on the arth#s surface causes Fthermal lag.F Dariable cloud co%er influences

solar gain potential. This means that latitude!specific fied window o%erhangs' while

important' are not a complete seasonal solar gain control solution.

Control mechanisms (such as manual!or!motori*ed interior insulated drapes'

shutters' eterior roll!down shade screens' or retractable awnings) can compensate for

differences caused by thermal lag or cloud co%er' and help control daily L hourly solar

gain re$uirement %ariations. Home automation systems that monitor temperature'

sunlight' time of day' and room occupancy can precisely control motori*ed window!

shading!and!insulation de%ices.



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Chapter.?

Con-lusions

&assi%e solar building design is a part of green building design by the pro%iding

this type of designJ we can able to use solar energy' which offers no cost 0 our

non!renewable resources can be sa%ed to a larger etent.

&assi%e solar building design pro%ides thermal comfort during %arious seasons'

lie summer' winter 0 it is %ery use full design to pro%ide natural %entilation in

the building' passi%e solar pro%ides natural light by installation of photo%oltaic'

which didnt re$uire any other source of energy' proper orientation of building

can be done by this type of design.

As we are seeing the day by day the earths weather condition is changing

improperly due to the pollution which we are maing on the earth' 0 global

temperature is also raising day by day' This year in -ndia we are obser%ing a



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Highest temperature of 6>o C' in north' so there is a lot of scope for this type of

construction which pro%ide us a complete comfort during all seasons and all

weathering condition.

-n western countries this type of construction is common scenario' and they ha%e

codal pro%isions for &assi%e solar design' but unfortunately in -ndia we are still

lacing behind' this is a %ery %ast study area to deal with' So i epect this report

may help us to now something about the need for this sub"ect.

Chapter.:

Referen-es.

5. nited state air force &assi%e solar design Handboo. .

7. California energy commission report on &assi%e solar design.

9. ASC "ournals

(ASC "ournal of architectural engineering %ol.5' no.5' march5::;' sep5::8).

6. Source boo for green and sustainable building design.

;. S ,epartment of ci%il engineers and energy conser%ation report.

8. S ,epartment of energy. (A report on passi%e solar system).



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