LG LC098HV4 Engineering Manual page 55

Method 2: Unconditioned Outdoor Air (Non-Ducted, Fan Assisted Ventilation)
When approved by local codes, the fan assisted ventilation method uses exhaust fans to remove air from the building, and outdoor air is
drawn into occupied spaces through a wall louver or gravity roof intake hood. Supply fans can also be used to push the outdoor air into the
space and building positive pressure will vent the exhaust air through louvers or roof-mounted exhaust hoods. Outdoor air is neither cooled
nor heated before entering the building.
This may result in loss of building pressurization control, increasing infiltration loads with adverse effects.
Advantages
• Outdoor air may be manually controlled by the occupant or auto-
matic controls may be installed to open/close outdoor air dampers
or to turn on/off ventilation fans.
• Useful for large open spaces like warehouses, garages, and
workshops.
• Outdoor air volume is a known quantity. Air loads may be easier to
calculate since fans will regulate the amount of outdoor air.
• May be used with the full lineup of Duct-Free Split system indoor
units.
Figure 32: Unconditioned Outdoor Air (Non-Ducted, Fan Assisted Ventilation).
OA Wall
Louver
BUILDING VENTILATION DESIGN GUIDE
Damper
Due to our policy of continuous product innovation, some specifications may change without notification.
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Disadvantages
• In some locations of the country, it may be difficult to control
humidity levels while outdoor air louvers/hoods are opened.
• Thermal comfort levels may be substandard when louvers/hoods
are opened.
• Indoor units may have to be oversized to account for the added
heating/cooling loads when louvers/hoods are open.
• Hot, cold, and/or humid areas may be present if the outdoor air is
not evenly distributed to the different spaces.
Methodology illustrations are for examples only and do not depict actual
indoor units for the specific outdoor unit pairing. These are generic illus-
trations to show ventilation design only.
Roof Fan
INTRODUCTION | 55