Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The downward spike in your OAT looks like a mistake in the weather file. It happens. You can confirm and manually correct this in the .epw file using a text editor or something like Elements (free). This should fix that anomaly.
The unmet hours are hard to diagnose without the model, but some suggestions:
1. Are you seeing unmet hours in all zones, or just the labs?
2. Graph the Air System Outdoor Air Minimum Flow Fraction and the Air System Outdoor Air Flow Fraction. Are your lab zones forcing the entire system to run at 100% OA much of the time?
3. Graph the boiler part load ratio. Is it running at full capacity during the times you are getting unmet hours?
4. Graph the VAV terminal damper positions and terminal outlet node temperature and flow. Are the terminals behaving as expected? (this depends on your damper heating action.
5. If the terminals are maxed out but you still aren't hitting setpoint, check that the Maximum Reheat Air Temperature in the VAV terminal matches the Zone Heating Design Supply Air Temperature (in the Sizing:Zone object for each zone). If you are sizing the zone expecting 105F air, but the terminal only supplies 95F air, you could have unmet hours.
| | 2 | No.2 Revision |
The downward spike in your OAT looks like a mistake in the weather file. It happens. You can confirm and manually correct this in the .epw file using a text editor or something like Elements (free). This should fix that anomaly.
The unmet hours are hard to diagnose without the model, but some suggestions:
1. suggestions:
