Displacement ventilation

A method of space conditioning where conditioned air is supplied at or near the floor. Since the air is supplied at very low velocities, a cool layer of air collects in the occupied zone resulting in comfortable conditions for the occupants. Buoyant forces remove heat generated by occupants and equipment, as well as odors and pollutants, all of which stratify under the ceiling and are extracted from the space by return or exhaust fans. Displacement ventilation systems were originally used in industrial facilities and subsequently in office buildings, auditoria, performing arts centers, and spaces with large interior volumes. These systems are effective in improving indoor air quality as well as providing energy savings when compared with a conventional fully mixed system.

References in periodicals archive

In recent years, there has been an increase in the availability of integrated operating room air distribution products.

Constructing Operating Room HVAC With Performance Assurances; An Alternate Approach

The research project was proposed by ASHRAE Technical Committee 5.3, Room Air Distribution, with ARI cosponsoring the project.

Fan-Powered VAV Terminal Units: Application and Modeling Implications From Past and Current Research

The transmission of exhaled small particles from one person to another in an indoor environment can take place both directly (in the microenvironment around the persons) and via the room air distribution. The impact of these transmission routes for two persons is investigated in detail by evaluating the exposure to gaseous substances (simulating particles <5 [micro]m) in a room with a vertical temperature gradient obtained by displacement ventilation.

Airborne cross-infection risk between two people standing in surroundings with a vertical temperature gradient

New chapters on room air distribution, integrated building design, and chemical, biological, radiological, and explosive incidents are contained in the new 2007 ASHRAE Handbook titled HVAC Applications.

ASHRAE publishes new Handbook volume

In a recent study, "Ventilation of Poultry Slaughtering and Processing Plants," authored by Albert Heber, associate professor of agriculture and biological engineering, Purdue University, West Lafayette, Ind., it was found that doors have a significant effect on room air distribution.

Opening doors to food safety and sanitation

Current room air distribution design practice does not take into account the air movement induced by the thermal flows from occupants, which often results in inaccurate exposure prediction.

Airflow characteristics and pollution distribution around a thermal manikin--impact of specific personal and indoor environmental factors

In 2001, a research proposal was presented to ASHRAE from TC 5.3, Room Air Distribution, to study building energy consumption differences when using parallel vs.

VAV Terminal Units: Looking Back, Ahead

Diffuse Ceiling Inlet Systems and the Room Air Distribution. in Clima 2010 : 10th Rehva World Congress: Sustainable Energy Use in Buildings.

Breathing and Cross-Infection Risk in the Microenvironment around People

The convective flow generated by a human body has a significant impact on the room air distribution and, thus, on the transport of pollution and contagious pathogens, inhaled air quality, thermal comfort, and, ultimately, occupants' performance and well-being.

Impact of geometry of a sedentary occupant simulator on the generated thermal plume: experimental investigation

These factors are what drive the science of room air distribution.

Basics of Well-Mixed Room Air Distribution

The Performance of Diffuse Ceiling Inlet and other Room Air Distribution Systems.

Interpersonal Transport of Droplet Nuclei among Three Manikins in a Full-Scale Test Room

Diffuse Ceiling Inlet Systems and the Room Air Distribution. in Clima 2010: 10th Rehva World Congress: Sustainable Energy Use in Buildings.

Breathing and cross-infection risk in the microenvironment around people