HVAC Strategies

Air Distribution Ducts Performance

• 

  Allison Bailes, III

  Principal
  Energy Vanguard
  Decatur, Georgia
• 

  Marcus Bianchi

  Senior Building Science Program Lead
  Owens Corning
  Littleton, Colorado

An important part of HVAC design involves distributing air to meet the heating and cooling loads of a house, usually calculated for a specific design load day. Improving home performance involves increasing air sealing and insulation levels of the home, leading to loads that are lower and less need for air volume to condition the home. This session will discuss air distribution basics and the challenges of delivering the design volumetric flow rate of air at the desired temperature. We will discuss the needs for insulating ducts, both from a thermal and an acoustic performance need. The relevant parameters that need to be delivered by the system, including proper air temperature at the supply, surface temperature above the dew point in cooling mode, and reduce heat gain and heat loss through the duct to install smaller equipment and to save money, will all be discussed. We will also discuss types of insulation, as well as buried ducts, reflective insulation, and code requirements.

 

Learning Objectives:

• Identify the thermal and flow requirements of air ducts
• Understand the mechanisms involved in air distribution and the important parameters that need to be controlled in air distribution systems
• Become familiar with the code requirements for insulation in ducts