Ventilation is an air distribution strategy that allows individuals to control the amount of ventilation received. The approach deliver fresh air more directly to the breathing zone and aims to improve air quality of inhaled air. Personalized ventilation provides a much higher ventilation effectiveness than conventional mixing ventilation systems by displacing pollution from the breathing zone far less air volume. Beyond improved air quality benefits, the strategy can also improve occupants thermal comfort, perceived air quality, and overall satisfaction with the indoor environment. Individuals preferences for temperature and air movement are not equal, and so traditional approaches to homogeneous environmental control have failed to achieve high occupant satisfaction. Techniques such as personalized ventilation facilitate control of a more diverse thermal environment that can improve thermal satisfaction for most occupants.
Local Exhaust Ventilation Systemaddresses the issue of avoiding the contamination of indoor air by specific high-emission sources by capturing airborne contaminants before they are spread into the environment. This can include water vapor control, lavatory bio effluent control, solvent vapors from industrial processes, and dust from wood- and metal-working machinery. Air can be exhausted through pressurized hoods or through the use of fans and pressurizing a specific area.
A local exhaust system is composed of 5 basic parts:
- A hood that captures the contaminant at its source
- Ducts for transporting the air
- An air-cleaning device that removes/minimizes the contaminant
- A fan that moves the air through the system
- An exhaust stack through which the contaminated air is discharged