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

Info@nwBuildings.org

www.nwBuildings.org