12/30/2013

Right-Size Your Ventilation Needs

Learn how demand control ventilation can reduce energy use

By

 
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    Scheduling alone for classrooms and conference spaces won’t reveal how many people are truly present on an hourly basis. DCV is ideal for dense and highly variable occupancies.

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    Fixed Vs. Demand Control
    If your building uses fixed ventilation yet has variable occupancy patterns, energy is wasted whenever excess air is supplied. Instead, implement demand control ventilation (DCV) to calculate occupancy and adjust air supply in real-time. As shown in this sample facility, different people counting strategies offer various levels of sensitivity.
    Ventilation
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    Credit: DOE

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A Breezy Solution
Demand control ventilation isn’t a flashy energy efficiency project, but it consistently generates payback under five years or less. Paybacks can also be achieved more quickly if the system incorporates lighting and electrical outlets (vampire energy) controls. For upfront investments, owners can expect to pay less than $100 for occupancy sensors, Nall estimates. CO2 sensors can cost several hundred dollars per unit, adds Lawrence.

“The installation costs for a DCV project vary significantly depending on building size, existing infrastructure, and control requirements. An owner can expect to pay approximately $1,000 to $2,000 per point on average,” Nohra adds.

Nall was recently involved with a renovation project that incorporated DCV by using occupancy sensors. A series of perimeter offices and those adjacent to an atrium were paired with a dedicated outside air system and variable speed fan coils.

Each 160-square-foot office has a two-position damper. The default setting for an unoccupied office delivers 10 cfm of outside air. Anticipating occupant diversity when the office is in use, the secondary position is configured for three guests at 25 cfm.

“This ensures that we’re providing the minimum ventilation for the maximum expected occupancy,” Nall stresses.

Whenever the system senses the room is unoccupied, it can scale back ventilation to 40% of peak flow. The project cost less than $1,000 per office and since the occupancy sensor controls ambient lighting and power receptacles, the payback is under five years. The DCV capability also meets the LEED credit for increasing ventilation by 30%.

Lawrence also oversaw a DCV project at the University of Georgia. The retrofit converted a single classroom, but has seen great success since its installation. Payback was achieved in less than two years and there are plans to adapt more areas in the future.

“Regardless of the actual design standard, energy savings with a DCV retrofit should focus on a comparison to the existing ventilation patterns, even if they do not match current codes or standards,” emphasizes Lawrence. “If a building is not providing ventilation that meets existing standards, then the primary benefits of DCV are indoor air quality.”

 

Jennie Morton jennie.morton@buildings.com is senior editor of BUILDINGS.

 


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Visit our website today to learn about the design flexibility of a Morton building and the endless possibilities of partnering with our designBUILD team.


Wood construction is both cost and energy efficient. Check out Morton Buildings and our designBUILD team online today to discover all the benefits of post-frame construction.


When choosing a metal-clad building for your next construction project, consider Morton Buildings, Inc., and their designBUILD team, we’ll make your dream a reality.

We Can Help You Reduce Energy by 30%

Our mission is to help our customers manage their buildings' energy costs, improve reliability, and enhance performance while having a positive impact on the environment.
CLICK HERE to find out how.

Add highly responsive multi-zone comfort to any building project, in any climate. Our CITY MULTI H2i R2- and Y-Series VRF systems give you flexibility to fit the needs of any building. Enjoy 100% heating capacity at 0°F outdoor ambient, and 85% heating capacity at -13°F outdoor ambient.  For more information, log on to www.mitsubishipro.com


Visit our website today to learn about the design flexibility of a Morton building and the endless possibilities of partnering with our designBUILD team.


Wood construction is both cost and energy efficient. Check out Morton Buildings and our designBUILD team online today to discover all the benefits of post-frame construction.


When choosing a metal-clad building for your next construction project, consider Morton Buildings, Inc., and their designBUILD team, we’ll make your dream a reality.

We Can Help You Reduce Energy by 30%

Our mission is to help our customers manage their buildings' energy costs, improve reliability, and enhance performance while having a positive impact on the environment.
CLICK HERE to find out how.

Add highly responsive multi-zone comfort to any building project, in any climate. Our CITY MULTI H2i R2- and Y-Series VRF systems give you flexibility to fit the needs of any building. Enjoy 100% heating capacity at 0°F outdoor ambient, and 85% heating capacity at -13°F outdoor ambient.  For more information, log on to www.mitsubishipro.com

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