1.
AIR DISTRIBUTION SYSTEM
2.POINTS CONSIDERED IN AIR DISTRIBUTION SYSTEM
3.BUILT UP AHU
4.FANS IN AIR CONDITIONING
5.TYPES OF FANS
CENTRIFUGAL FAN
PROPELLER FAN
6.DUCTS
7.DUCT SHAPES
CIRCULAR
RECTANGULAR
8.OTHER SUPPORTING COMPONENTS
9.DIFFERENT TYPES & SHAPES OF THE DUCTS
SRUSHTI CHITNIS
SECOND YEAR M. ARCH. ( ENV)
SUSTAINABLE BUILDING DESIGN, PRINCIPLES,MATERIALS &TECHNOLOGY- II
HEATING, VENTILATION AND AIR CONDITIONING
AIR DISTRIBUTION SYSTEM
IT DIRECTS THE AIR FROM AIR CONDITIONING EQUIPMENT TO
THE SPACE TO BE CONDITIONED & THEN BACK TO THE
EQUIPMENT.
THE SYSTEM COMBINES FAN, DUCT & OUTLETS.
THE FAN ASSEMBLY CONNECTING TO A STRAIGHT RUN OF
DUCT AT THE END OF WHICH OUTLETS ARE INSTALLED.
THE SYSTEM BECOMES COMPLEX BECAUSE OF
ELBOWS
BENDS
TURNING VANES
SIZE REDUCTIONS
LOUVRES
INTRICATE OUTLETS
THESE ADD RESISTANCE TO THE SYSTEM.
TOTAL RESISTANCE OF THESE COMPONENTS TO THE FLOW OF
AIR + FRICTIONAL RESISTANCE CAUSED BY PASSAGE OF AIR
OVER THE SURFACE OF STRAIGHT DUCT ARE THE MAJOR
FACTORS IN DETERMINING THE SIZE OF FAN, FAN MOTOR &
AMOUNT OF AIR PRESSURE.
HEATING, VENTILATION AND AIR CONDITIONING
AIR DISTRIBUTION SYSTEM
TOTAL RESISTANCE OF THESE COMPONENTS TO THE FLOW
OF AIR & FRICTIONAL RESISTANCE CAUSED BY PASSAGE OF
AIR PASSING OVER THE MAJOR FACTORS IN DETERMINING
THE SIZE OF THE FAN, FAN MOTOR & AMOUNT OF AIR
PRESSURE.
HEATING, VENTILATION AND AIR CONDITIONING
AIR DISTRIBUTION SYSTEM
BUILT UP AHU:
•IT IS A CONSTRUCTED
ROOM WITH
INSULATION TO
WALLS,ROOF
DESIGNED,
•OPENINGS FOR
RETURN AND SUPPLY
AIR DUCTS
•GOOD FLOORING IS
DESIRABLE.
HEATING, VENTILATION AND AIR CONDITIONING
FANS IN AIR CONDITIONING
THE SUCCESSFUL
OPERATION OF AIR-
CONDITIONING DEPENDS
UPON THE PROPER
SELECTION OF THE FAN & ITS
OPERATIONAL
PERFORMANCE UNDER
VARIABLE LOAD
CONDITIONS.
HEATING, VENTILATION AND AIR CONDITIONING
TYPES OF FANS
1. CENTRIFUGAL FAN:
• IT IS ENCLOSED IN AHU.
• ENTIRE FAN IS INSTALLED IN A HOUSING OR
PLENUM. HOUSING SHOULD PERMIT
FORCED AIR FLOW IN TO FAN SCROLL.
• COMMONLY USED IN COMMERCIAL &
RESIDENTIAL SYSTEM INSTALLATIONS.
• SUITABLE FOR VARIOUS APPLICATIONS FOR
HEATING, COOLING, HUMIDIFICATION &
VENTILATION ETC.
• THERE ARE TWO BLADE TYPES:(DEPENDS
ON CUPPING & DIRECTION OF ROTATION)
I) FORWARD &
II) BACKWARD CURVED.
HEATING, VENTILATION AND AIR CONDITIONING
i) FORWARD CURVED:
• EXACTING NATURE BY
OPERATION
• DUCT RESISTANCE SHOULD BE
DETERMINED QUITE
ACCURATELY.
• OPTIMIZING OF HP IS NECESSARY
IN THIS DESIGN
ii) BACKWARD CURVED:
NOT AS CRITICAL IN RELATION OF
DUCT RESISTANCE.
SPEED & HP RELATION NEVER
CHANGES.
HEATING, VENTILATION AND AIR CONDITIONING
DAMPER
SCROLL
WHEEL
SHAFT
PLUMMER
BLOCK
MOTOR
SCROLL:CASING OR ENCLOSER FOR SHAFT & WHEEL
SHAFT: AROUND WHICH WHEEL ROTATES
WHEELS: CYLINDRICAL IN SHAPE ,CONTAINS BACKWARD OR
FORWARD
CURVED BLADES WITH PLATES
IT IS FIXED ON FLOOR PLATE.
HEATING, VENTILATION AND AIR CONDITIONING
DIFFERENT TYPES & SIZES OF
CENTRIFUGAL FANS
HEATING, VENTILATION AND AIR CONDITIONING
2. PROPELLER FAN:
•GENERALLY USED IN SMALL S
SCALE AIR CONDITIONING UNITS. W
E
•STATIC PRESSURE GENERATED BY E
PROPELLER FAN IS LOW & HENCE P
DISPLACE AIR IS VERY LOW.
•SPEED OF FAN MEASURED @ TIP
OF THE FAN IN RPM (V= 300-500
M/S)
•FAN SHOULD KEPT IN INSULATED
ENCLOSURE TO AVOID NOISE
POLLUTION.
•SWEEP (Ø OF FAN) GENERALLY
9”-18”
HEATING, VENTILATION AND AIR CONDITIONING
DUCTS
•THE DUCTS SHOULD BE DESIGNED TO CARRY THE
REQUIRED QUANTITY OF AIR FROM THE FAN TO AN
AIR CONDITIONED SPACE WITH MINIMUM LOSSES
AND ITS SIZE SHOULD BE MOST ECONOMICAL.
•THE VELOCITIES IN THE DUCT MUST BE HIGH
ENOUGH TO REDUCE THE SIZE OF THE DUCTS BUT
THEY MUST BE LOW ENOUGH TO REDUCE THE NOISE
LEVEL & PRESSURE LOSSES TO ECONOMIC POWER
REQUIREMENTS FOR RUNNING THE AIR
CONDITIONING PLANT.
HEATING, VENTILATION AND AIR CONDITIONING
DUCT SHAPES
BASIC SHAPES SQUARE, RECTANGULAR & CIRCULAR
CIRCULAR : IT IS MOST ECONOMICAL & HENCE MORE PREFERRED.
IT CARRIES MORE AIR IN LESS SPACE, HENCE REQUIRE
LESS DUCT MATERIALS,
LESS DUCT SURFACE,
LESS FRICTION,
LESS INSULATION REQUIRED,
LESSER THE DUCT SURFACE BETTER FOR FAN ENERGY
EFFICIENCY.
RECTANGULAR : THESE DUCTS ARE VERY POPULAR.
EASIER TO WORK WITH FLAT SURFACES.
ACCEPT LIMITATION OF SPACE IN CEILING FLOOR
JOISTS
MATERIALS: USUALLY THEY ARE IN G.I, M.S.( GAUGES 18,20,22 &24 )
FIBREGLASS, TILES,CEMENT, PVC, PLASTIC, ALUMINIUM
HEATING, VENTILATION AND AIR CONDITIONING
The system becomes complex
because of-
ELBOWS,
BENDS,
TAKE -OFFS,
TURNING VANS,
SIZE REDUCTIONS,
DAMPERS AND LOUVRES.
These add resistance to the system.
Turning Vanes
R < Elbow End Cap
(generally 90°)
R
R > Bend Collar :for
(smooth curve)
supply &
return
HEATING, VENTILATION AND AIR CONDITIONING
HEATING, VENTILATION AND AIR CONDITIONING
HEATING, VENTILATION AND AIR CONDITIONING
DIFFERENT TYPES & SHAPES OF THE DU
HEATING, VENTILATION AND AIR CONDITIONING
DIFFERENT TYPES & SHAPES OF THE
DUCTS
HEATING, VENTILATION AND AIR CONDITIONING
DIFFERENT TYPES & SHAPES OF THE
DUCTS
HEATING, VENTILATION AND AIR CONDITIONING
DIFFERENT TYPES & SHAPES OF
THE DUCTS
HEATING, VENTILATION AND AIR CONDITIONING
HEATING, VENTILATION AND AIR CONDITIONING
