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New Occupancy Control Could Slash Energy Expenses for Ventilation

Up to 18% savings possible without affecting comfort, researchers say


Up to 18% savings possible without affecting comfort, researchers say.

Pairs of advanced ventilation controls now in development are designed to adjust ventilation according to room occupancy.
Credit: PNNL

A new building control in development could cut the average large office building’s energy bill by up to 18% without affecting comfort, according to researchers at the Pacific Northwest National Laboratory, operated by the DOE.

The device would be able to customize fan speeds and air movement depending on the number of people it senses in different areas or zones. Ventilation sensors in use today operate with an all-or-nothing strategy – the system runs when it detects a presence, even if the room isn’t full. However, a room that’s far from capacity doesn’t need as much ventilation as a room with a large crowd in it.

“This is the reason you often feel cold when you’re in a big space like a conference room or cafeteria without a lot of people,” says engineer Guopeng Liu, the lead author of the report. “Technology available today doesn’t detect how many people are in a room, so air flow is at maximum capacity nearly constantly. This creates a big demand to re-heat the air before it enters the rooms. It takes a lot of energy to keep you comfortable under those circumstances.”

The prototype building used in the model had 12 stories and a basement and covered roughly 500,000 square feet.

Using past studies of occupancy patterns and typical office temperature parameters (which required the simulation to heat the building if it was under 70 degrees F. and cool starting at 75, with a 10-degree setback on weekends), the team found that the advanced controls would save at least $40,000 in 13 of the 15 U.S. climate regions.

In fact, two cities – Baltimore and Fairbanks – promised savings of more than $100,000 because the building would have a reduced need to heat cold outdoor air being pumped in.