Advantages of a Dedicated Outdoor Air System

Dedicated Outdoor Air Systems could be engineered for high energy performance buildings.

 

We hope you might enjoy this article. This is one of our many eco-snacks series. We will continue on the topic of the reducing energy consumption through Dedicated Outdoor Air System (DOAS).

Synopsis:

A building ventilation system can take care of many functions such as: heating, cooling, humidity control, odors, indoor air quality, etc. Several technologies exist in the industry. One of which is a system named Dedicated Outdoor Air System. What is a Dedicated Outdoor Air System or DOAS?

The DOAS’s provides ventilation air to achieve acceptable indoor air quality. ASHRAE 62.1 allows to establish the amount of outside air required according to space area and number of occupants. Other considerations such as space activities and contaminants are important. 

Glimpse into an eco-friendly solution:

A DOAS uses separate equipment to condition all of the outdoor air brought into a building for ventilation. A DOAS delivers it to each zone, either directly or in conjunction with local HVAC equipment serving those same zones. The local HVAC equipment controls zone temperature.

This allows the selected fan to be of low power requirements. The reason is that DOAS requires a lower airflow. Of course, some design consideration needs to be given to the conditioning of that air (humidity, heat, cooling, etc.).

Decentralized DOAS could provide additional savings because shorter ductwork requires less static pressure. This means reducing the required fan head pressure. That decentralization could be done by having one system per floor or per zone.

DOAS coupled with heat recovery, DCV, zone-level terminals such as chilled beams and radiant panels drives down energy costs even further.

DOAS comes with many benefits including:

  • Energy savings of 15% to 30% or more;
  • Lowering initial investment costs by reducing plant equipment sizes;
  • Providing better indoor air quality by delivering the correct amount of outdoor air to the spaces all the time;
  • Providing better humidity control.

Conclusion:

Selecting the right equipment for the building is a process that can be go beyond acquisition costs. The engineer could also investigate operating costs which for some energy systems accounts for more than 75% of the lifetime ownership costs. This could help the owner make a better decision.

We hope this article was informative to you.

Which other areas could energy professionals help you in reducing your energy bills? Our next article will look into other avenues of energy reduction. Stay tune for upcoming articles and feel free to give us a call or write us.

Ecovision Consultants
+1 (888) 294-8802
www.ecovision.ca

References:

Life-Cycle for DOAS with VAV – ASHRAE Journal April 2018

Common Pitfalls in design and operation of DOAS – ASHRAE Journal Sept 2018

Design Consideration for DOAS – ASHRAE Journal

What is compressed air – NRCAN

picture – Kendeda Fund

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