Introduction to Urban Design
GATEWAY COLLEGE OF ARCHITECTURE AND DESIGN, SONIPAT
HARYANALecture -04 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture LECTURE -04 VENTILATION FOR PASSIVE COOLING OF
BUILDING Ventilation in warm and humid climate Techniques for
Passive Cooling VENTILATION FOR PASSIVE COOLING OF BUILDINGSAir
flow in a building is either due to the pressure differences ,
caused by temperature differences [stack effect] or due to pressure
differences of the wind . Window play a dominant role in inducing
indoor ventilation due to wind forces . The various parameters that
affect the ventilation are:ClimateArea of fenestration/locationWind
direction Volume of the roomShading devicesWire meshes/fly
screensInternal partitions
1.STACK EFFECTStack ventilation , the principle of which depends
upon the buoyancy of the warmer air causing the air to rise and
leave the building from a higher outlet.This way the heavier cooler
air is replaced via a lower inlet.Lecture -01 Sustainable
Architecture B.Arch. G.C.A.D. Asst. Prof. Lenin Sachdeva Asst.
Prof. Parul Saini Sustainable Architecture STACK EFFECTStack
ventilation , the principle of which depends upon the buoyancy of
the warmer air causing the air to rise and leave the building from
a higher outlet.This way the heavier cooler air is replaced via a
lower inlet.Lecture -01 Sustainable Architecture B.Arch. G.C.A.D.
Asst. Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture 2.VENTILATION DUE TO WIND FORCESWhen wind strikes a
building ,a region of higher pressure is created across the
building in the direction of the incident wind[windward wall] . The
sides ,leeward wall and roof are all subjected to reduced pressure
.Therefore , a pressure gradient is created in the direction of the
incident wind.
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture 3.ROOM WITH WINDOWS ON ONE WALL ONLY
The available wind velocity in a room with a single window on
the windward side is about 10% of the outdoor velocity at point up
to a distance one sixth of the room width from the window.
4.EFFECT OF ORIENTATION ON VENTILATION
The orientation of a window with respect to the most probable
wind direction has considerable effect on the internal wind
speed.
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture 5.OUTDOOR WIND MANAGMENTLocal topography and surface
texture can greatly affect the wind conditions for any
building.Obstruction such as vegetation can greatly reduce wind
speed , whereas the land relief can enhance or diminish the wind
speed.
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture 6.EFFECT OF LOUVERS VERANDAH AND FLY SCREENVarious
construction elements such as louvers ,a veranda before the windows
, subdivision of the internal , space and the presence of fly
screens effect the air movement inside .
7.TREES AS WIND DEFLECTORSIt may not be always be possible to
locate the openings in the windward direction due to reasons like
the site restriction solar radiation , privacy etc.To some extent
the limitation can be overcome by designing suitable wind
deflectors.
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture 8.WIND TOWERThe hot ambient air enters the tower
through the openings in the tower and is cooled ,when it come in
contact with the cool tower and thus becomes heavier and sinks
down.When an inlet is provided to the rooms with an outlet on the
other side, there is a draft of cool air.After a whole day of heat
exchange , the wind tower become warm in the evening.
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture 9.COURTYARD EFFECTDue to the incident solar in the
courtyard , the air in the courtyard becomes warmer and rises up.
To replace it , cool air from the ground level flows through the
louvered openings of the room , thus producing the airflow.
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture 10.AIR VENTA typical vent is a hole cut in the apex of
a domed or cylindrical roof. Openings in the protective cap over
the vent direct wind across it .When air flow over a curved surface
, its velocity increases resulting in lowering of the pressure at
the apex of the curved roof , thereby ,inducing the hot air under
the roof to flow out through the vent.
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture 11.SOLAR CHIMNEYA solar chimney utilises the stack
effect , as already described but here the air is deliberately
heated by solar radiation in order to create an exhausting effect
.The use of solar chimney is advisable for regions ,where very low
wind speeds exist.
Lecture -01 Sustainable Architecture B.Arch. G.C.A.D. Asst.
Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture Reference PRATICAL HAND BOOK ON ENERGY CONSERVATION IN
BUILDING Lecture -01 Sustainable Architecture B.Arch. G.C.A.D.
Asst. Prof. Lenin Sachdeva Asst. Prof. Parul Saini Sustainable
Architecture
