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I am running into a wall and can not find a solution to my problem.

I have a single zone building with a constant air volume mechanical system. The ventilation rate is fixed on a schedule at 0.19 m3/s. 27 people come in and out of the room on a schedule. The CO2 should rise to about 1200 ppm and then reach steady state. This is a school so there are 180 days of class. The contaminant balance works correctly most of the time. But a couple of days for only some of my weather files, it does the calculation incorrectly and the CO2 shoots up. I've included an example where ventilation is blue line and CO2 is red line. Occupancy is the same for each day.

image:

‪https://ibb.co/KwtDdtq

I am running 70 files from historical weather and not every simulation has this problem. Only a handful do, but I don't see any pattern when it happens. My timestep is 5 minutes.

I could obviously post-process the answer, but I need to make sure that the contaminant balance is working because I'm going to be running some DCV control schemes.

I am running into a wall and can not find a solution to my problem.

I have a single zone building with a constant air volume mechanical system. The ventilation rate is fixed on a schedule at 0.19 m3/s. 27 people come in and out of the room on a schedule. The CO2 should rise to about 1200 ppm and then reach steady state. This is a school so there are 180 days of class. The contaminant balance works correctly most of the time. But a couple of days for only some of my weather files, it does the calculation incorrectly and the CO2 shoots up. I've included an example where ventilation is blue line and CO2 is red line. Occupancy is the same for each day.

image:

‪https://ibb.co/KwtDdtq

I am running 70 files from historical weather and not every simulation has this problem. Only a handful do, but I don't see any pattern when it happens. My timestep is 5 minutes.

I could obviously post-process the answer, but I need to make sure that the contaminant balance is working because I'm going to be running some DCV control schemes.

I am running into a wall and can not find a solution to my problem.

I have a single zone building with a constant air volume mechanical system. The ventilation rate is fixed on a schedule at 0.19 m3/s. 27 people come in and out of the room on a schedule. The CO2 should rise to about 1200 ppm and then reach steady state. This is a school so there are 180 days of class. The contaminant balance works correctly most of the time. But a couple of days for only some of my weather files, it does the calculation incorrectly and the CO2 shoots up. I've included an example where ventilation is blue line and CO2 is red line. Occupancy is the same for each day.

image:

‪https://ibb.co/KwtDdtqhttps://drive.google.com/file/d/1JJ80iXB2jsdhJuSXPDe5vhGP2ptAum3u/view?usp=sharing

I am running 70 files from historical weather and not every simulation has this problem. Only a handful do, but I don't see any pattern when it happens. My timestep is 5 minutes.

I could obviously post-process the answer, but I need to make sure that the contaminant balance is working because I'm going to be running some DCV control schemes.

I am running into a wall and can not find a solution to my problem.

I have a single zone building with a constant air volume mechanical system. The ventilation rate is fixed on a schedule at 0.19 m3/s. 27 people come in and out of the room on a schedule. The CO2 should rise to about 1200 ppm and then reach steady state. This is a school so there are 180 days of class. The contaminant balance works correctly most of the time. But a couple of days for only some of my weather files, it does the calculation incorrectly and the CO2 shoots up. I've included an example where ventilation is blue line and CO2 is red line. Occupancy is the same for each day.

https://drive.google.com/file/d/1JJ80iXB2jsdhJuSXPDe5vhGP2ptAum3u/view?usp=sharing

I am running 70 files from historical weather and not every simulation has this problem. Only a handful do, but I don't see any pattern when it happens. My timestep is 5 minutes.

I could obviously post-process the answer, but I need to make sure that the contaminant balance is working because I'm going to be running some DCV control schemes.