taken from CutterEdge Buildings, the weekly e-mail service from Cutter Information Corp.

Wisconsin engineer Mark Lentz has achieved the goal of designing > heating, ventilating, and air-conditioning (HVAC) systems that not only provide 100% outdoor air -- for improved indoor air quality -- but also slash energy costs substantially.  It is a goal the HVAC industry has claimed for years is impossible.

"An important added benefit is that the system could potentially reduce the threat of bio-terrorism for a wide variety of facilities," Lentz says.  "First, the system's active anti-microbial air-cleansing process intercepts and destroys contaminants coming from the outdoors.  It also inhibits the spread of contaminants released indoors such as anthrax spores by eliminating recirculation through HVAC air-handling systems."  Lentz's system captures particles 0.3 of a micron in diameter or larger. Anthrax spores generally are several microns in diameter.  A micron is one-millionth of a meter or 0.0039 inch.

Lentz's "hybrid" design is revealed and discussed in detail in the > exclusive special report "How to Supply 100% Outdoor Air and Save Significant Energy Too," which appeared in the September 2001 issue > of Cutter Environment's monthly newsletter *IEQ Strategies*.

The design, based on an approach Lentz calls a "Regenerative Double-Duct System", is not only competitive in price to conventional systems, but also costs less to maintain.  What's more, it relies on readily available equipment.

How does it achieve its startling performance?  The hybrid design uses a whole-system approach that takes full advantage of basic thermodynamic principles that are widely known but frequently ignored in the world of HVAC.

As described in *IEQ Strategies*, the double-duct system proved itself under unfavorable conditions: in a retrofit of the Wausau West High School in Wausau, Wisconsin, a brick-and-block building built in 1968 with no windows (so no opportunity for passive solar gain), no vapor barriers, and no insulation, despite Wisconsin's cold winters.

Rising fuel costs caused the school to slow its ventilation fans, reducing the air-exchange rate and worsening indoor air quality.  Rather than install a 440-ton chiller, Dennis Wald, the director of physical plant for the Wausau School District, turned to Lentz, a professional engineer and the winner of the Distinguished Service Award of ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers).

Lentz's system for the high school ventilates the building with 100% outdoor air, and an official state report said the system reduced building energy costs by about 21% or $100,000 a year.  (Lentz maintains that the actual savings were even higher, perhaps more than 35%.)

In conventional HVAC systems, Lentz explains, cooling is the dominant process, since large buildings produce and build up excess heat that the system must disperse. In his designs, Lentz turns a heat exchanger into an evaporative cooler that works over a wide range of applications in a variety of spaces.  Rather than having cooling be its major process, Lentz's system manages ventilation as the dominant process.



In the past few decades, volatile organic compound (VOC) concentrations in indoor environments have risen dramatically, to the point where they could be impacting human health and comfort.

Ironically, VOCs remain a mystery to many in the indoor air quality field.  Indoor air and health specialists know that VOCs are serious contaminants of indoor air, but until recently little information was available on the nature of VOCs, let alone how to deal with them.

*Volatile Organic Compounds in Indoor Environments*, the only practical, comprehensive study of its kind, demystifies VOCs.  In 400+ pages, Dr. Dagmar Schmidt Etkin presents the results of worldwide research on VOCs: their sources, health effects, and strategies for reducing their concentrations in indoor air.

Order *Volatile Organic Compounds in Indoor Environments* today!

For more information, or to reserve your copy, call 1-800-964-5118 or 781-648-8700, send an e-mail to sales@cutter.com, or visit http://cutter.com/energy/reports/vocs.htm .