The document discusses various strategies for ventilating buildings through natural or mechanical means. It describes natural ventilation driven by wind or buoyancy forces, as well as mechanical ventilation using ducts or underfloor distribution. Specific natural ventilation techniques are explained, including wind-driven cross ventilation using openings on opposite sides of a building, and buoyancy-driven stack ventilation which uses chimneys or atriums to draw in cool air and exhaust warm air. Roof ventilators, underfloor distribution systems, and concepts like "breathing buildings" which utilize natural air flow are also outlined.

1. Ventilation and Air
Movement
SUBMITTED TO: SUBMITTED BY:
DR. VASHIMANT KUNWAR PARITOSH
PULKIT GOYAL
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2. Introduction
 Ventilation strategies
 Natural ventilation
 Types of Natural Ventilation Openings
 Cooling sensation from airflow
 Wind-driven cross ventilation
 Buoyancy-driven stack ventilation
 Underfloor air distribution (UFAD)
 Breathing building
 Wind Turbo Roof Air Ventilator
 Conclusion
 References
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3. Ventilation strategies
 Natural ventilation
 flow driven by wind and temperature
 Forced air – mechanical ventilation
 fan-driven through ducts
 Traditional HVAC
 mechanical cooling, overhead distribution
 Unconventional HVAC
 mechanical cooling, unconventional distribution
 Hybrid ventilation
 combinations of the above systems
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4. Natural Ventilation
 Ventilation driven by natural pressure forces
• wind
• buoyancy - due to temperature differences; the ‘stack effect’
 The ventilation of indoor environments is also necessary to maintain
the required levels of oxygen and air quality in a space.
 For breathing and general fresh air require about 10 ls-1 per person
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5. Types of Natural Ventilation
Openings
 Windows :
Windows sliding vertically, sliding horizontally, tilting,
swinging
 Doors, monitor openings and skylights.
 Roof Ventilators (weather proof air outlet).
 Stacks connecting to registers
 Specially designed inlet or outlet openings.
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6. Cooling sensation from airflow
0
2
4
6
8
10
0 0.5 1 1.5 2 2.5 3 3.5
Airflow (m/s)
Coolingsensationdeg.C
Source: Natural Ventilation in Buildings, Tony Rofail,
NEERG seminar, 31 Aug 2006, Windtech Consultants
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7. Wind-driven cross ventilation
 Wind-driven cross ventilation occurs via ventilation
openings on opposite sides of an enclosed space.
 The building floor span depth in the direction of the
ventilation flow must be limited to effectively
remove the heat and pollutants from the space by
typical driving forces.
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8. Wind-driven contd…
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9. Buoyancy-driven stack ventilation
 Buoyancy-driven stack ventilation or displacement ventilation (DV)
relies on density differences to draw cool, outdoor air in at low
ventilation openings and exhausts
 A chimney or atrium is frequently used to generate sufficient
buoyancy forces to achieve the needed flow.
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10. Buoyancy-driven contd…
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11. Portland Building, UK 5/9/2015
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12. Underfloor air distribution
(UFAD)[3]
 Underfloor air distribution (UFAD) is an air distribution
strategy for providing ventilation and space conditioning in
buildings as part of the design of an HVAC system.
 UFAD systems use an underfloor supply plenum located
between the structural concrete slab and a raised
floor system to supply conditioned air through
floor diffusers directly into the occupied zone of the
building.
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13. 5/9/2015
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14. 5/9/2015
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15. Wind Turbo Roof Air Ventilator[2]
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 It spins with the slightest breeze, creating
an upward draft which draws hot air,
odor, smokes, dampness and other
pollutant particles upwards.
 Creat invisible convection current, and in
the process extract them together with
pollutant particles, which has become
hot due to the buildings exposure to long
hours of sunlight and manufacturing
processes and due to other pollutants
particles within the building.

16. Contd..[3]
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 As the stale and hot air is extracted by the Air
ventilators, it is replaced by fresh air at ambient
temperature entering through the natural openings

17. Breathing building[1]
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18. Conclusion
 Low cost
 Easy installation
 Protect from high heating
 No water leakage
 Anti-corrosion, anti-acids and bases, anti-oxidation
 Light weight
 Long use
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19. References
1. Breathing building-
http://www.breathingbuildings.com/products/nat
ural-ventilation-explained
2. UADF-
http://cbe.berkeley.edu/underfloorair/applyingTheTechn
ology.htm
3. Wind Turbo Roof Air Ventilator-
http://www.airventilatorindia.co.in/Eco_AirVentilat
or.html,
http://www.realvents.com/Roof_ventilators.html,
http://www.svspoweredventilators.com/
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