Building Ventilation Design Guide; Decoupled Dedicated Outdoor Air System (Ddoas) - LG Multi IV Engineering Manual

Building Ventilation Design Guide

ASHRAE 62.1 and local codes specify the minimum volume of outdoor air that must be provided to an occupied space. Outdoor air is
required to minimize adverse health effects, and it provides acceptable indoor air quality for building occupants. The five methods of
accomplishing this with LG Multi V IV systems are summarized here.
Disclaimer
or evaluated by LG Electronics, U.S.A., Inc., In all cases, the designer, installer, and contractor should understand if the suggested method is
used, it is used at their own risk. LG Electronics U.S.A., Inc., takes no responsibility and offers no warranty, expressed or implied, in law or in
• For a complete copy of Standard 62.1-2010, refer to the American Standard of Heating and Air Conditioning Engineers (ASHRAE)
website at www.ashrae.org.
• For more information on how to properly size a ventilation air pretreatment system, refer to the article, "Selecting DOAS Equipment with
Reserve Capacity" by John Murphy, published in the ASHRAE Journal, April 2010.
Method 1: Decoupled Dedicated Outdoor Air System (DDOAS)
Provide a separate, dedicated outdoor-air system designed to filter, condition, and dehumidify ventilation air and deliver it directly to the
conditioned space through a separate register or grille. This approach requires a separate independent ventilation duct system not
associated with the Multi V IV system.
LG recommends using the DDOAS method in all installations.
Advantages
• Does not add additional heating or cooling loads to indoor units.
• May be used with a full lineup of the indoor units.
• The outdoor air unit may supply "neutral" air to the occupant space
even when the Multi V indoor unit fan changes speed or cycles on
and off. DDOAS controls do not have to be interlocked with the
Multi V IV system.
• In lieu of installing localized smaller outside air treatment
equipment throughout the building, this method centralizes the
ventilation air source making service and filter changes easier.
• Third-party demand control ventilation controls are more readily
accommodated.
Outdoor Air
Outdoor Air Unit / ERV
BUILDING VENTILATION DESIGN GUIDE
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Disadvantages
• Ceiling space is required to accommodate ductwork between the
centralized outdoor air unit and ceiling diffusers.
Methodology illustrations are for examples only and do not depict
generic illustrations to show ventilation design only.
Ceiling Diffuser
Multi V Ceiling-Cassette Indoor Unit
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