IAQ Control With Back-To-School Simplicity

August 5, 2004
/ Print / Reprints /
ShareMore
/ Text Size+
As mechanical manager for Leon County Schools in Tallahassee, Fla., Dave Ventry is responsible for maintaining the mechanical and HVAC operations of 50 school campuses in the district. When the district faced the need to meet the Florida version of the ASHRAE 62 ventilation code, which requires the introduction of 15 cfm of outdoor air per person, Ventry sought a district-wide solution for controlling humidity levels while complying with the state of Florida's new fresh air requirements.

The age of the equipment was another reason for the mechanical renovation, as students and teachers were feeling uncomfortable in a number of schools.

To address these issues, the district scheduled five schools for mechanical retrofitting during a five-year span starting in 2002. Roger Walsh, P.E., Walsh Engineering Inc., was selected by the district to work with Ventry to develop a plan for schools within the district, including Killearn Lakes Elementary School.

Challenging Conditions

"The original system at Killearn Lakes was a mechanic's worst nightmare," said Ventry. "Every classroom and administrative office had its own small water-source heat pump unit to cover its HVAC and IAQ needs. You can imagine the maintenance headaches with literally 60 separate units."

Clearly, the first order of business was to create accessible mechanical spaces. Walsh and Ventry devised a plan to construct a mezzanine floor above each of the school's single-story wings. Key to the mechanical solution of achieving the outdoor air code requirement was the need to control the level of humidity being introduced into the buildings.

"If the humidity isn't controlled, you've just opened yourself up to perfect conditions for bacteria and toxic mold," said Walsh.

Walsh worked with engineers from Applied Mechanical Equipment of Jacksonville, Fla., to pre-sent to Ventry the idea of using Desert Aire Q-Pumpsâ„¢ combined with TotalAireâ„¢ 5- to 20-ton dehumidifiers, each equipped with an enthalpy wheel to maximize the sensible and latent heat recovery. Unlike traditional heat pumps, which use a two-element reverse cycle system, Desert Aire's Q-Pump uses a four-element refrigeration system that relies on the dehumidifier's reheat coil for heating, thus eliminating the need for a reversing valve.

"To be honest," Ventry stated, "I was leery when I first looked at the Desert Aire unit with its circuitry, configuration circuits, and recovery wheel. My initial thought was, ‘Gosh, that's complicated,' but when I really looked at it and broke it down, I soon realized it is quite simple. When I say ‘simple,' I mean that it is precise at doing what it's supposed to do and appeals to my common sense."

After becoming comfortable with Desert Aire's approach, Ventry requested detailed technical information from Desert Aire and studied the TotalAire unit's control logic.

"I wanted to make full use of our existing controllers, so I wrote my own software program to make sure our controllers would match the Desert Aire controller requirements," Ventry said.

The Desert Aire system at Killearn Lakes has been in place since October 2002, and Ventry can vouch for its performance. "I'm very pleased. The Desert Aire system has reduced our maintenance costs substantially and has delivered on everything promised."

For more information, visit www.desert-aire.com.

Publication date: 08/09/2004

Did you enjoy this article? Click here to subscribe to The NEWS Magazine

You must login or register in order to post a comment.

Multimedia

Videos

Image Galleries

2014 MCAA Annual Convention

Scenes from the 2014 MCAA Annual Convention in Scottsdale, Ariz.

Podcasts

NEWSmakers: Julian Scadden

Training is an ongoing process. Julian will discuss how you can generate maximum return on time and energy invested training by following a three part process. Listen to this podcast to get expert tips on training, tracking and follow up. 

More Podcasts

THE MAGAZINE

ACHRNEWS

NEWS 04-14-14 cover

2014 April 14

Check out the weekly edition of The NEWS today!

Table Of Contents Subscribe

SERVICE CALLS POLL

Which statement on service calls best applies to your business?
View Results Poll Archive

HVACR INDUSTRY STORE

plumbing-hvac.gif
2014 National Plumbing & HVAC Estimator

Every plumbing and HVAC estimator can use the cost estimates in this practical manual!

More Products

Clear Seas Research

 

Clear Seas ResearchWith access to over one million professionals and more than 60 industry-specific publications, Clear Seas Research offers relevant insights from those who know your industry best. Let us customize a market research solution that exceeds your marketing goals.

DON'T MISS A THING

Magazine image
 
Register today for complete access to ACHRNews.com. Get full access to the latest features, Extra Edition, and more.

STAY CONNECTED

facebook icontwitter iconyoutube iconLinkedIn i con