Atmospheric indoor climate in ppm


Is it possible to obtain the indoor atmospheric climate in ppm using LBT tool by incorporating additional strings into the HB model to OSM component?

I have checked the topic in the forum, but since I’m not familiar with additional strings, I would appreciate guidance from more experienced users.

Thanks in advance.

Hi @tru ,

Yes. You just need to add the following text to the IDF to get the CO2 calculation to happen:

    Yes,                     !- Carbon Dioxide Concentration
    Outdoor CO2 Level,       !- Outdoor Carbon Dioxide Schedule Name
    No;                      !- Generic Contaminant Concentration

    Outdoor CO2 Level,       !- Name
    ,                        !- Schedule Type Limits Name
    420;                     !- Hourly Value

Then, you can request CO2 concentration outputs like:

Zone Air CO2 Concentration

Here is a sample: (52.7 KB)


Hi @chris ,

Thanks a lot. Your help is always invaluable.

Based on your inputs, I’ve tried to set up a code for Zone air C02 concentration with natural ventilation and hybrid system following the EMS application guide. Since this is my first attempt, I have a few questions:

  1. How can I get the open factor to work in different stages, not just fully open or closed?
  2. By using the IDF file you provided, will Honeybee automatically recognize any HVAC system, or does it only recognize the default system “ideal air” (for example, a VAV system)?

Please find my .gh file attached. Thank you in advance for your help.

Co2_Temperature and HVAC (132.2 KB)

HI @tru ,

If you are tying to model something this custom, then it is really up to you to do your own research about the EnergyPlus objects that you are using by looking through the Input Output Reference. I know people who have use CO2 sensors to increase mechanical ventilation rates in EnergyPlus but I don’t recall nay posts on this forum that have looked at an automated natural ventilation strategy based on CO2. So you’ll have to do much of the work of figuring out how you want to model it and verifying for yourself that it’s simulating as you expect.

The last bit of guidance I can give you here is that I know the EMS actuator that you have there is not setting the opening factor of the window but rather the flow rate of the ventilation object. If you use the Airflow Network, it is possible to set an open factor of an individual window with the EMS. You can see a sample of this over here on the Pollination forum:

The example file in that part of the post also answers this question:

You can’t simulate the gradual opening of a window using just the components that we ship with honeybee but you can post-process the OSM to convert the simple open/closed controls into ones that do gradual opening.

I don’t really understand this question but it sounds like you can get your answer by just running a simulation with detailed HVAC and making sure the results make sense to you. You can figure it out, @tru . I believe in you.