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1Ventilation and Air Movement

SUBMITTED TO: SUBMITTED BY:

DR. VASHIMANT KUNWAR PARITOSH

PULKIT GOYAL

04/17/2023

2Introduction

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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3Ventilation 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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4Natural 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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5Types 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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6Cooling sensation from airflow

0

2

4

6

8

10

0 0.5 1 1.5 2 2.5 3 3.5

Airflow (m/s)

Co

olin

g s

ensa

tio

n d

eg. C

Source: Natural Ventilation in Buildings, Tony Rofail, NEERG seminar, 31 Aug 2006, Windtech Consultants

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7Wind-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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8Wind-driven contd…

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9Buoyancy-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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10Buoyancy-driven contd…

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11

Portland Building, UK

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12Underfloor 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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15Wind Turbo Roof Air Ventilator[2]

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.

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16Contd..[3]

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

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17Breathing building[1]

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18Conclusion

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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19References

1. Breathing building-http://www.breathingbuildings.com/products/natural-ventilation-explained

2. UADF-http://cbe.berkeley.edu/underfloorair/applyingTheTechnology.htm

3. Wind Turbo Roof Air Ventilator-http://www.airventilatorindia.co.in/Eco_AirVentilator.html, http://www.realvents.com/Roof_ventilators.html, http://www.svspoweredventilators.com/