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Why the fan schedule is not working?

asked 2015-03-01 10:53:45 -0500

hugopft's avatar

updated 2015-03-01 14:35:39 -0500


I´ve been working in a HVAC system and I am facing a problem regarding to the fans that I had applied to my model. The fan is a constant volume fan. I made a schedule in order to turn the fan off during the weekends and between time period of 7:00pm and 7:00am during week. Then I associated this schedule to each fan. The result shows no reduction in the energy consumption if compared with the case in which the fans are kept turn on 24 hours per day, and every day of the week. It seems that the schedule made by me it is not being working. A bring some pictures here to show in details how I am dealing with it. My conclusion is based on the fan consumption which remains the same, even when my schedule is applied and in the zone mechanical ventilation, which shows that this fan is working continuously, without interruption (last picture).


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@hugopft, welcome to UnmetHours! Two quick things. 1. Your images did not upload properly. Try again? 2. Please tag your question with the software you are using, e.g., 'energyplus', 'openstudio', 'equest', 'ies-ve', etc. This will help route the question to the right people.

__AmirRoth__'s avatar __AmirRoth__  ( 2015-03-01 11:02:20 -0500 )edit

Thanks Amir Roth for the tips!!!

hugopft's avatar hugopft  ( 2015-03-01 11:08:45 -0500 )edit

@hugopft, I think the first image isn't showing the schedule that you are having problems with.

Geraldo Pithon's avatar Geraldo Pithon  ( 2015-03-01 17:06:08 -0500 )edit

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answered 2015-03-02 10:20:03 -0500

updated 2015-03-02 23:27:55 -0500

Leave the fan schedule as always on. Instead set the HVAC operation schedule from the "Control" sub tab. This will translate to the appropriate availability manager, taking into account night cycle settings.

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Here is the model with an HVAC Schedule coming on at 8 am and off at 5 pm. I plotted the schedule value vs supply outlet node flowrate and found expected agreement.

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First of all thanks for your answer Kyle Benne. I made the changes as you suggested, but the fan consumption remained the same.

hugopft's avatar hugopft  ( 2015-03-02 15:09:31 -0500 )edit

If you want to provide a link to your model I'll take a look.

Kyle Benne's avatar Kyle Benne  ( 2015-03-02 15:29:46 -0500 )edit

Here is the link with the model and the weather file.

Thanks for the attention.

hugopft's avatar hugopft  ( 2015-03-02 16:05:59 -0500 )edit

@hugopft I took a look at your model. I didn't see the Fan Constant Volume schedule shown in your original screenshot so I made a new schedule named "HVAC Schedule" and set as the availability schedule on "0BSL DE EQUIPPackaged Rooftop Heat Pump". I plotted the supply outlet node flow rate vs the HVAC schedule value on the air flow rates where zero as expected when schedule was off.

Kyle Benne's avatar Kyle Benne  ( 2015-03-02 23:25:17 -0500 )edit

Kyle Benne, thanks very much. Now the schedule is working properly.

hugopft's avatar hugopft  ( 2015-03-03 06:11:21 -0500 )edit

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Asked: 2015-03-01 10:53:45 -0500

Seen: 392 times

Last updated: Mar 02 '15