AIR LEAKAGE WASTES ENERGY

Recent studies have demonstrated that modern commercial buildings are not airtight.   Pressurized underfloor plenums exaggerate losses of supply air before it can enter and cool occupied spaces.  APACS avoids significant air leakage and consequent energy losses by operating at near atmospheric pressure in the underfloor plenum.

Data on significant measurable leakage rates are summarized in "Myths About Building Envelopes," by Andrew K. Persily, Ph.D., in the ASHRAE Journal.  [Click here] to review the article (PDF).

This article was published in ASHRAE Journal, March 1999 © 1999 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.  This posting is by permission of ASHRAE, and is presented for educational purposes only.  ASHRAE does not endorse or recommend commercial products or services.  This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE.  Contact ASHRAE at www.ashrae.org. 

The ASHRAE Underfloor Air Distribution (UFAD) Design Guide describes some of the advantages of zero-pressure plenums over pressurized plenums.  [Click here] to review an excerpt (PDF).