Fans Are Consuming Too Much Energy

asked 2017-04-27 01:11:32 -0600

mcdonaa1 gravatar image

updated 2017-08-06 16:17:46 -0600

I am running an OpenStudio model with a packaged rooftop air conditioner. My fans are consuming 1/3 of the energy or more despite turning heating nearly off, and cooling way down. Is it because the fan continues to pump in Outside Air?

Any idea on how to reduce the fans energy consumption? It should be half or less of what it currently is...


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Is the design flow rate what you're expecting? If it's variable volume, is it operating seasonally at the rates you expect?

Adam Hilton gravatar image Adam Hilton  ( 2017-04-27 07:27:27 -0600 )edit

If you're using a constant volume fan that is always on, and the system availability is always on, then the fan will run continuously.

mdahlhausen gravatar image mdahlhausen  ( 2017-04-27 11:21:54 -0600 )edit

So how do I regulate either variable or constant fans? I would like to turn them down significantly. It seems to be operating all the time. I only want the fan to operate when cooling is being called for, or a necessary OSA infusion, and it is necessary to blow air through the ducts. Otherwise, it should be off. And all of that only during occupancy. Unoccupied hours, it should not be operating at all.

mcdonaa1 gravatar image mcdonaa1  ( 2017-04-27 11:27:23 -0600 )edit

Regulate the fan speed using variable volume terminals. There is a terminal AirTerminal:SingleDuct:VAV:NoReheat that will keep the fan at minimum during heating and reset to 100% for increasing cooling load. Assign the damper to Normal heating action. Assign an availability schedule to the air loop that tells it when you want it to operate.

Adam Hilton gravatar image Adam Hilton  ( 2017-04-27 12:36:52 -0600 )edit