November 29, 2002—Though it has been around for hundreds of years, research, development and use of displacement ventilation gained popularity in industrial applications in the 1970s, mostly in Scandinavian countries. It became more widely used for commercial premises in the 1980s and is now gaining popularity in other countries.
A new book, Displacement Ventilation in Non-Industrial Premises, serves as a comprehensive design manual. The book explains the benefits and limitations of displacement in commercial ventilation and outlines where ventilation should be applied. Case studies for a restaurant, office cubicle, auditorium, meeting room and classroom are included.
Published by the Federation of European Heating and Air-Conditioning Associations (REHVA), the book is being sold in the United States by ASHRAE. With displacement ventilation, warm contaminants rise to the ceiling, contaminated air is extracted, and fresh, cool air is supplied at floor level. Displacement ventilation has two main advantages over traditional mixing systems, according to Hkon Skistad, editor of the book. First, it ensures improved indoor air quality throughout occupied spaces and removes more contaminants at high level than conventional mixing air-distribution systems, Skistad said.
“Second, as an efficient use of energy due to its capability to remove exhaust air from the room at a higher temperature than that in the occupied zone, this strategy allows a higher inlet temperature for the same internal heat gain/load.”
Therefore, less cooling is needed for a given temperature in the occupied spaces, and longer periods of free cooling with better air quality in the occupied spaces ensues.
The book also points out the limitations of displacement ventilation. The technique is no marvel that can solve all ventilation problems, but a principle that has definite advantages when applied correctly, Skistad said. The cost of Displacement Ventilation in Non-Industrial Premises is $39, plus shipping and handling.
To order, contact ASHRAE Customer Service at 800/527-4723 (United States and Canada), fax 404/321-5478, by mail at 1791 Tullie Circle NE, Atlanta, GA 30329, or visit ASHRAE online.
