Alternate energy systems in Architecture

Why is it important ?Resource depletion Global warming

Relevance to the Building Industry?

• Buildings are responsible for 40 % of the total energy

• 70% of this energy is used to heat or cool these buildings.

• 21% green house gas emission come from the buildings.

• Use natural energy (sun, wind, geothermal, biomass etc.) to conserve conventional energy for achieving thermal comfort.

• Thermal comfort refers to comfortable indoor conditions (temperature, humidity, air movement)

Sun is the only Source of day light on earth.( One should be clear that the light coming to earth due to scattering in space is not considered as daylight , for example moon light.)

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Daylight Area: Area with in the relevant contour.

Daylight Penetration: The maximum distance to which a given daylight factor contour penetrates into the room

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1. Intensity2. Flux3. illumination4. Illuminance

1.Intensity(I): amount of light emmitted by the sourcemesured in candela(cd)

One candela = intensity of 1/60 cm2 uniformaly emmitting black body radiator at the mpt of platinum(3223 F)

2.Flux(f): amount of flow of light, per unit solid anglemesured in lumens(lm)

One lumen= flow of light emitted by a unit intensity point source within a unit solid angle

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3.illumination(e): amount of flux falling per unit areamesured in lux

One Lux = unit flux falling upon a unit area, i.e. Lm/m2.

4.illuminance(l): brightness of surfacemeasures in apostilb(asb) or cd/m2

Defined as:1.If a Light source is of 1cd intensity having surface area of 1 m2 , its illuminace is 1cd/m2

2. If a completely reflecting and diffusing surface, has an illumination of 1 lux, its luminance is 1asb, 1cd/m2=3.14 asb.

1. Intensity2. Flux3. illumination4. Illuminance

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sun

Azimuth

Altitude

Azimuth: Angle between the meridians passing through the position of sun and the north point.

Altitude: Angular distance of any point of celestial sphere , measured from the horizon, on the great circle, passing through the body.

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Foot prints

Sky lights

Light shelves

Light pipe

Atria/light wells

Saw tooth

Clerestories

Fresnel lenses/ Holographic films

FOOT PRINT

ATRIUM

Light shelve

Skylight

Light pipes

Light well

FOOT PRINT

CELESTORIES

Saw tooth

Largest Solar Powered BuildingDezhou, Shangdong Province innorthwest China

The solar furnace at Odeillo