Getting started with ventilation simulation in OS

asked 2017-04-26 22:09:03 -0500

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Dear all,

I am a (very new) research staff in agricultural engineering field and want to simulate energy balance of greenhouses.

Currently, I am trying to model very simple greenhouse with natural ventilation. With OpenStudio, I set natural ventilation to "Zone Equipment" in "Thermal Zones" and ran the model. However, it seems that there was no ventilation as it is shown in results (I checked the Zone Ventilation Total Heat Loss Energy).

The description of the model is like; with one thermal zone and two windows, using weather data downloaded from E+ webpage (Tokyo), without anything set in the space.

I would like to know what is the possible solution for this.

Best regards,

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answered 2017-04-27 00:16:25 -0500

David Goldwasser

20295 ●94 ●14 http://www.openstudio.net/

updated 2017-04-27 00:20:41 -0500

@rtsuchiya, you aren't doing anything wrong, you are hitting this issue which effects Zone Ventilation Design Flow Rate when there isn't another piece of zone equipment on the zone. If you check `Simple Ventilation' in the tabular output it probably also shows 0 (in addition to what you are seeing in time series results).

You should be able to work around this by also adding a Fan Zone Exhaust object with a max flow rate of 0 (so it doesn't do anything). Let me know if that doesn't work. In test I just did I had fan after the zone ventilation but it may be fine in either order (but I'm not sure).

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Thank you for your advise, I tried. However, it seems the problem was not solved yet.

Result shown in the Table (Zone Equipment Detail) is like;

Object Sizing Sizing Units Description Value Value Units Count

OS:Fan:ZoneExhaust 0.00 cfm Fan Efficiency 0.60 fraction

OS:ZoneVentilation:DesignFlowRate

(Ventilation is still blank. Outdoor Air is too.)

For Natural Ventilation, I chose the schedule whose type is OnOff and set the value 1 all the day long.

Do I need to provide you more information?

rtsuchiya ( 2017-04-27 02:06:46 -0500 )edit

Zone Equipment Detail, Air Loops Detail, and Plant Loops Detail sections of the OpenStuido Results are meant to give a quick overview of model elements across loops and zones. For many objects you get additional detail beyond the object name, but for some you just get the name. That doesn't mean there isn't more information. Also these tables just echo back input data.

Zone Ventilation Design Flow Rate is one of the objets that just reports the name. To see if it is functioning in the model look at the "Avg. Simple Ventilation" column of "Outdoor Air Table"

David Goldwasser ( 2017-04-27 09:46:10 -0500 )edit

Thank you. I understood that those variables are just echo. But, when checking "Avg. Simple Ventilation", the value is still 0. This means the ventilation doesn't work... I am afraid that I made a simple mistake in my setting. I will check more carefully later, but if you still have more tips, I'd like to know that. Thank you very much for your kind comment.

rtsuchiya ( 2017-04-27 23:20:11 -0500 )edit

In addition, the term "None" is shown in the far left column of the table. Does this mean I missed inputting something?

rtsuchiya ( 2017-04-27 23:28:29 -0500 )edit

If you post a link to the file or email it to OpenStudio@nrel.gov I can take a look.

David Goldwasser ( 2017-04-28 08:51:59 -0500 )edit

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