Case Studies: HVAC Renovation

Mechanical Engineer: Nami Nahid

Client: Holiday Inn
12759 Fort Campbell Lane
Oak Grove Kentucky

Date: 03.2017

Description: After evaluation, the mechanical engineer determined the excessive humidity and challenges the hotel was experiencing was the result of negative building pressure due to existing HVAC design.

Building Pressure Analysis: When the air inside a building is under negative pressure relative to the outside air, many indoor environmental problems can develop or worsen, especially in a hot/humid climate. Affected areas can range from localized areas of building cavities (in exterior walls or ceilings) to excessive humidity throughout the building affecting all materials and occupants.

Scope of Work:

• Removed two (2) rooftop package units that served the hotel corridors and lobby and replaced with Daikin Rebel 100% outdoor air units. The existing return duct was capped below the roof level and the remaining duct served as a transfer air pressure balance between the floors.
• Removed one (1) package unit that served the conference room and replaced with a Daikin Rebel package unit equipped with modulating gas heating, variable inverter cooling compressor, and hot gas reheat coil dehumidification cycle.
• Seventeen (17) powered roof exhaust fans were removed and replaced with gravity relief hoods.
• A new wall mounted exhaust fan operated by a thermostat was installed in the boiler room to provide ventilation during heat build-up.
• Pipe insulation was removed and replaced with labels on all water pipe in the boiler room.
• A Daikin mini-split unit was installed in the Breakfast Preparation Room for additional cooling.
• Louvers in the Laundry Room were cleaned, re-wired, and placed back into operation for proper ventilation.

The Outcome:

The hotel is now experiencing positive building pressure and humidity levels within acceptable range, thus eliminating potential structural problems and uncomfortable comfort levels.