passive solar building design sas

7/30/2019 Passive Solar Building Design Sas

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PASSIVE SOLAR

BUILDING DESIGN

PRESENTED BY:SASMITA DASREGD. NO.:0901109029CIVIL BRANCH


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Proposed model of passive

solar system There are 2 type of proposed

model

1.glass pane model

2.trombe wall model 1.Glass pane model: in this model solar energy passes

directly into the living space

through south facing windows. The floors or walls provide storage

for night time heating.


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The Incidence angles of solar radiation depend upon

latitude , window orientation , day of the year , time of

day.

This absorbed energy could be stored, transportedthrough the envelope by conduction, transported to the

interior air by convection, or transported to another area

by radiation (long wave).

Q si + Q r i hiA i (Ti - Ta) - A i (Ti - T) / Ri = (mc) i dTi/dt (1) The index i (i = 1, 2 11) is used to label the areas. In

addition, conservation of energy for the interior air is

expressed as:

=111iAihi(Ti

Ta)

r (mc)a (Ta

T) = (mc)a dTa/dt (2) Qri =(Ji - Ti 4) iAi / (1- i) (3)


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Where the radiosities Ji were determined from

temperatures by solving:

Ti 4 - Ji + (1-i)/ ( iAi ) [(J=111jj- Ji) AjFji)] = 0 (4)

Equation (4) was solved by Gauss elimination for eachtime step. Equations 1 and 2 were numerically integrated

by the first order explicit Euler method:

T (t+t) T (t) + t(dT/dt) (5)

The convective film coefficients are calculated by h = (k/L) C (Rayleigh number) m (6)


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This figure illustrates the measured and simulated testcell air temperatures along with the measured insulation

and ambient temperature for the glass model.

The mean deviation of the simulated temperatures fromthe measured temperatures was found to be -11C & the

maximum deviation was 5.4C.


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2.Trombe wall model

In trombe wall model heat transfer through the wall was

by conduction with no convective mixing.

Qri + (UA) c (Tr- T1) + (UA) 1 (T - T1) = (mc) 1 dTi/dt (7)

Radioactive heating by the storage wall is: Qri = AT (b4 - T14) / [1/ T + (AT/A1) (1- 1)/ 1] (8)

A heat balance for the living space room air yielded:

hTAT (b - Tr) + (UA)c (T1 - Tr) + (mc)r(T -Tr) + r(mc)r(T0 -

Tr

) = (mc)r

dTr

/dt (9) The average air temperature in that space was

calculated as:

Ts = 2 mcTr + (UA) w T + hTAT 0 (10)

2 mc + (UA) w + hTAT


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Ts = 2 mcTr + (UA) w T + hTAT 0 (10)

2 mc + (UA) w + hTAT

Conduction heat transfer through trombe wall is numerically

solved by these equation

x (t +t) = x -x(t) = (1 - 2 ) x (t) + x +x(t) (11)

Where = t/ x2.

The mean deviation of the simulated

temperatures from the

measured.


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CONTENTS:

IntroductionAbout Energy

(i)Energy sources

(ii)Energy uses

Activities for designing solar homes

Passive solar building designs

Principles of passive solar buildings

Conclusions

References


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INTRODUCTIONPassive solar techniques make use of the steady supply of

solar energy by means of building designs that careful balance

their energy requirements with the buildings site and window

orientation.

The term passive indicates that no additional mechanicalequipments is used other than the normal building materials.

All solar gains are brought in through windows.

All passive techniques use building elements such as walls,

windows, floors and roofs, in addition to exterior buildingelements and landscaping to control heat generated by solar

radiation.


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Solar heating designs collect and store thermal energy from

direct sunlight.

Passive cooling minimizes the effects of solar radiation

through shading or generating airflows with convectionventilation.

The benefits of passive solar techniques include simplicity,

price and the design elegance of fulfilling ones need with

materials at hand.


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ABOUT ENERGYRenewable energy technologies play a very important role inreducing green house emissions in our society.

Energy sources:

-The society we live in uses energy and to runsystem and services depend upon energy .

-Where this all this energy come from? All the energy

come from natural world, so where can energy be

found, and in what form?-Energy can be classified into two components.

i)Renewable Energy

ii)Nonrenewable Energy


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1.Renewable energy

Renewable sources of energy are those which are

continuously replenished by natural processes on the

earth within relatively short period e.g. 24 hrs, a week

or a year.

Example: Solar, wind and hydro energy.


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2.Nonrenewable Energy

Nonrenewable energy sources are those with finite

Reserves, and are not renewed within our life times.

They may take millions or billions of years to form.

Example: these are fossil fuels such as oil, gas and coal

and nuclear fuel i.e. Uranium.


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Energy uses:

Prior to Industrial Revolution; human societies are largelydependent on renewable energy sources such as solar

energy.

Solar energy is used to heat, cool and light homes and

dry crops.


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ACTIVITIES FOR DESIGNING SOLARBULDINGS

1.Identify the Task

You are aiming to design and build a model of solar

efficient house. What does this mean? What are thekey features of such house? How many pepole will

live in this house? Where is it to be located? What is

the local climate like? What other problems do u

need to think about before commencing the design?

2.Project brief

This should include the names of people

in group, answer the questions

above in step 1.


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7.Final testing

Modify model is tested

8.Final report

9.Presentation

10.Extension activity

A written report that includes details of research , project

brief , design, model, test activities and conclusions.

Model is presented.

A number of homes in this area is visited and passivesolar and energy efficient features are identified.


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PASSIVE SOLAR BUILDING DESIGN Background Information: Passive solar homes can provide comfort with saving on

energy cost.

It ensures energy from the sun or controlling the entry ofthe sun.

Buildings are designed as a combined solar collector

and thermal storage facility to heat the home in winter as

well as incorporating principles that stop the sun fromoverheating the house in summer.

These are otherwise called as energy

efficient homes.


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Principles of passive solar

buildings 1.climatic conditions: Local climatic conditions; such as suns varying

movement during seasons; the direction of prevailing

wind and temperatures and humidity must beconsidered.


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2.Orientation

The direction or orientation of the house will haveconsiderable influence on its energy efficiency and comfort.

To heat living areas in winter by utilizing the sun these

rooms need to be placed on north wide of the home with

windows allow winter sunlight into this room.

Conversely the home needs to be oriented to minimize the

entry of sun


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3.windows;shading and

ventilation The large windows in the house should be on

north side.

This will allow winters sun to warm the living

areas.

These windows should also be protecected by

using some sort of shading device.

To keep out the hot summer sun also provide a

correctly sized eave and verandah over the

windows.

Windows to the cold south side of the house

should be kept minimum.

West facing windows need to be shaded from

sun.


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4.Building materials

Heavyweight building materials such as concrete floors

& brick walls can absorb winter warmth from directsunlight.

This warmth is released into the room when the sun has

moved on.

In summer these heavy materials absorb heat from theroom & keep temperatures low and comfortable.

Different colors are better absorbing the heat from the

sun than others.


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5.Insulation

Insulation of walls and ceilings will help prevent heatfrom the house in winter & entering the house in

summer.


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6.Landscaping

Appropriate landscaping can improve both summer and

winter conditions in home. Plants can be used to block strong winds, cool hot summer

winds, provide shade & reduce sunlight reflection. Features such as ponds or pools on the windward side can

assist with evaporative precooling.


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Advantages & disadvantages:

Advantages:(i) Saves money

(ii)environmentally friendly

(iii)independent/ semi-independent(iv)low/ no maintenance

Disadvantages:

(i)High cost of semiconducting materials

(ii)High cost of energy

(iii)Large area of installation

(iv)Influence by presence of clouds


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conclusions

The best part of passive solar building design is that they

have no moving parts.

They can perform effortlessly & quietly without

mechanical & electrical assistance.

Most design consideration can be made & implemented

using standard building materials & basic construction

skills.

Heating bills can be reduced by as much as 40%

annually & also improve comfort of living place.

Simple techniques can consumed huge energy through

years.

passive solar building design sas

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