improved IAQ, cooling energy savings,
and better acoustics for high performance buildings.
Displacement ventilation (DV) is an alternate air distribution
method for commercial and industrial spaces.1 Used since the late
1970s in Northern Europe and more recently in U.S. schools, DV
disproves the common perception that improving indoor air quality
(IAQ) in an air-conditioned space must result in higher energy
consumption. By providing supply air directly to building
occupants, IAQ is improved. By conditioning only the lower occupied
portion of the space, cooling energy can be reduced.
This design brief provides an introduction into the design and
application of DV. It addresses the following issues:
- Comparison with other air distribution systems
- Energy savings and IAQ improvements
- Typical applications
- Architectural design options
- HVAC design considerations
DV can reduce cooling energy use in all California climates. It is
especially beneficial in temperate climates, where the higher
supply air temperature increases opportunities for free cooling.
Schools, restaurants, theaters and auditoriums, atria, and other
open spaces with high ceilings are excellent applications. It
relies on a steady supply of cool air (near 65°F) at the floor to
carry heat and contaminants towards the ceiling exhaust. Initial
incremental costs for diffusers are offset by simplified ductwork
and the possibility for a smaller chiller, often resulting in a
lower total system cost.
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