Infiltration/VentilationPerArea Rate in Set EnergyPlus Zone Loads - Question

[ayezioro]

Hi, I have a couple of questions of this input. The calculation method you implemented is Flow/Area, which is supposed to be m3/s-m2. The units you request are l-s-m2. There is a difference among the. So just want to be sure which is the correct.

As a personal flavor i wish you allow AirChanges method. This i understand. The previous is for much technical users. The thing is that the input values for infiltration are critical for the results. I'm afraid of a bad use of this input.

The other question is, where the Ventilation input goes to in the idf (I assume it is ZoneVentilation:DesignFlowRate, but want to be sure)? Also there i wish for the ACH method.

Thanks, -A.

[chriswmackey]

@ayezioro , I am sorry. That label of l/s/m2 is a mi-labeling on my part. It is supposed to be m3/s-m2. I just changed the description and uploaded it to the githib. I also wish that this input was ACH (it would make my life so much easier). I think I am going to make a converter of ACH to m3/s-m2 for input zone geometries that should help this problem. We can leave this issue open until I make such a component.

[ayezioro]

OK, I was looking for how to translate from m3/s-m2? Do you have the formula or link that makes the conversion? I (think) i didn't find something clear ... (i'm lazy now).

[ayezioro]

As for the Ventilation question, can you give some insights?

[chriswmackey]

@ayezioro , I am guessing that you are talking about translating from m3/s-m2 to ACH. To do this, all that you have to do is multiply your ACH value by the volume of the room (in m3). This will give you the total airflow into your zone in m3/h. Next you need to divide this by 3600 since there are 3600 seconds in one hour. This will give you your airflow in m3/s. Finally, you need to divide this number by the floor area of the zone (in m2) to get m3/s-m2. So the conversion can only be done if we know the zone geometry and this is what my component will do.

The ventilation should be going into ZoneVentilation:DesignFlowRate but I just noticed that one of my HB IDFs does not have this object. @mostaphaRoudsari , do you know why this might be?

[ayezioro]

Hi, After some discussions on this issue (unfortunately it was held in a different issue) i came up, with the great help of Chris to this example (and component) for translating ACH to m3/s-m2. Can be used for both infiltration and ventilation rates. So the user needs to input only the desired/required ACH without the need to deal with such unfriendly units. Let me know what do you think: https://www.dropbox.com/s/pkiw2rvrjkvn9vt/ACH2m3_s-m2%2BLightDensityPerAreaCalculator.gh?dl=0 The example combines both LightCalculator and Inf/Vent calculator (I'm still not successful with the icons design ...) -A.

[chriswmackey]

@ayezioro ,

We never closed out this issue after you made your awesome component but I am glad that we did not as I now have a few extra things to be added. Unless you beat me to it, I will:

1) Add an output to your component that gives the total Flow/Zone (which helps when setting air flow for fan-driven natural ventilation).

2) Add a component to calculate infiltration flow by square meter of facade (which it seems a lot of people use as the facade is the origin of infiltration leaks).

-Chris