Ductless Heat PumpsDuctless Heat PumpsVentilationVentilation
Gary NordeenGary NordeenBill Kingrey, P.E.Bill Kingrey, P.E.
11/5/08 AFE Webinar11/5/08 AFE Webinar
IntroductionIntroduction
This presentation is an overview of ventilation requirements and methods for existing commercial buildings.
This is not intended as a design guide, only to provide an overview of the issues related to ventilation in commercial buildings. ASHRAE 62.1 is the applicable standard.
How Much Ventilation Air?How Much Ventilation Air?
From International Mechanical Code (IMC) Chapter 11 or ASHRAE 62.1 • 15 CFM – 20 CFM per person
depending on building occupancy• Number of people assumed in any area
is also given in the table
Ventilation Air System Ventilation Air System AlternativesAlternatives
• Existing HVAC system• Constant Volume • Variable Air Volume
• Dedicated outside air system• Hole in the wall• AAHX module
• Open window(s)
Existing Building Existing Building Ventilation RatesVentilation Rates
This presentation assumes that your existing building ventilation is adequate. If this is not the case, we suggest you hire a qualified specialist to review your outside air settings and occupancy assumptions.
See notes page on this slide, for further details on existing VAV and Constant Volume systems
Hole in the Wall VentilationHole in the Wall Ventilation• For units with outside air connections • Provide wall cap and a two-position
damper motor• Barometric damper not recommended
• Provide time clock, occupancy sensor or building control system connection to shut damper when not occupied
• Provide a single small fan with ductwork, filter and controls to serve multiple indoor units
Ventilation from an Ventilation from an Air-to-Air-Heat ExchangerAir-to-Air-Heat Exchanger
• Recommended for 24-hour facilities• Higher installation and maintenance
cost, lower operating cost • Connect to the building EMCS and set
to provide air during working hours• Install outlet(s) of AAHX near indoor
unit(s)• Install exhaust inlets in bathrooms or
above copier and FAX machines
Open Window VentilationOpen Window Ventilation
• Most codes allow you to use natural ventilation by opening the windows
• Operable window area must be at least 4% of the room area (IBC)
• Think about security issues
More InformationMore Information
Northwest Building Efficiency Center
866-929-6232
www.nwBuildings.org
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