USPS Marriott Hotel & Convention Center/Norman, Oklahoma

The Problem.  Humidity was a huge problem in the Lobby.  The system cooling the lobby was a chilled water air handling unit (AHU).  The Hotel maintenance staff had closed off the outside air to the AHU serving the Lobby because it was getting too hot.  A humidity problem was created because the building was no longer pressurized.  So when the entry doors opened, hot humid air would rush in and mix with the cold air in the lobby and water would condense out of it.  I couldn't simply fix the pressurization problem by reopening the outside air dampers because then the building would still not be cool enough.

The Fix.  The building needed additional cooling to be able to open up the outside air dampers and have sufficient cooling.  So I decided the best solution was to add a Temtrol custom AHU in the ceiling of the Lobby.  It was a 15 ton custom AHU with reheat for humidity control.  The new unit gave them the additional cooling capacity they needed as well as more precise temperature/humidity control.

Avoid Air Infiltration.  Air infiltration is when outside air is introduced to the building through the building openings instead of the air conditioning system.  If a building is pressurized by introducing outside air through an AHU it will push air out through the building openings and block infiltration.  You want air to be introduced to the building through the mechanical systems so the moisture can be removed before it enters the space and you can avoid humidity problems.