Re: [EnergyPlus_Support] Re: Need help for Naturally Ventilated Model

Small world, Joe. Some of the students in my office (having officially worked in my office for a while now are being taken onto staff this year having finished MEng), studied and still have irregular contact with Prof. Feustel, who was the 1st author on COMIS back in the day. I last had contact with him whilst working on my paper on modelling human driven window ventilation modelling. PS. For those if you who were unaware, Dr. Gu has implemented thermal comfort driven window ventilation, since e+v5, i.e. there are objects for AFN that can help you do this

On 9 Dec 2016 3:23 am, "Joe Huang YJHuang@xxxxxxxxxxxxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

Stuart,

That's interesting information! Does running CONTAM3DExport result in a tighter or a looser coupling between EnergyPlus and the airflow modeling? When I worked on the first implementation of an airflow model (COMIS) into EnergyPlus back in the day, it was what Jan Hensen would call a "ping-pong" and not an "onion" approach. One of the dirty secrets from my work was finding that the solutions would oscillate by time step. I had proposed making the link a half-onion (??) , i.e., redo the thermal calculation using the air flows computed by the air flow modeling, but unfortunately my funding got cut just at that point.

Joe
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang@whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
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"building energy simulations at your fingertips"
On 12/8/2016 12:38 PM, 'Dols, William Stuart (Fed)' william.dols@xxxxxxxx [EnergyPlus_Support] wrote:
NIST, the developers of CONTAM, have also enable the coupling of CONTAM with EnergyPlus directly. This coupling features a tool, CONTAM3DExport, that you can use to generate an EnergyPlus model from a CONTAM model. The process is documented in the “Working with EnergyPlus” section of the CONTAM User Guide. CONTAM3DExport can be used to generate an Airflow Network Model as well. See the following reference: Dols, W. S., S. J. Emmerich and B. J. Polidoro (2016). "Coupling the Multizone Airflow and Contaminant Transport Software CONTAM with EnergyPlus using Co-simulation." Building Simulation 9: 469-479.

CONTAM and associated tools are available from the website that Joe mentioned. http://www.bfrl.nist.gov/IAQanalysis/software/index.htm

- Stuart

W. Stuart Dols National Institute of Standards and Technology Engineering Laboratory Indoor Air Quality and Ventilation Group 100 Bureau Drive MS 8633 Gaithersburg, MD 20899-8633 301-975-5860 www.bfrl.nist.gov/IAQanalysis
From: EnergyPlus_Support@yahoogroups.com [mailto:EnergyPlus_Support@yahoogroups.com] Sent: Thursday, December 08, 2016 2:31 PM To: EnergyPlus_Support@yahoogroups.com Subject: Re: [EnergyPlus_Support] Re: Need help for Naturally Ventilated Model
The EnergyPlus documentation should explain the IDF objects that are used for the multi-zone air-flow modelling, which are very much tied to the thermal modeling of the building, i.e., walls, windows, doors, etc., except that instead of defining their thermal properties you are defining their air-flow properties, such as leakage area, and in the case of windows their operating schedules.

Bear in mind that EnergyPlus is using the AIRNET program to do the multi-zone air flow modeling. If you want more information about this that you don't find in the EnergyPlus documentation, you could also look at the CONTAM User Manual (www.bfrl.nist.gov/IAQanalysis/CONTAM/userguide.htm ). CONTAM is the successor program to AIRNET with a user-friendly GUI added.

Joe
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang@whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"
On 12/8/2016 9:46 AM, 'Edward G. Lyon' eglyon@xxxxxxx [EnergyPlus_Support] wrote:

Although perhaps a bit more effort, you could also look at ODS Studio. This Australian group has levered Blender as a graphic interface, OpenFoam as a CFD tool, and E+ as a calculation engine. Mark Pitman has written some C++ modules and Python code to assist in generating airflownetwork models for E+ analysis. There are some video demonstrating the code that may help you understand the general process, even if you go in a different direction to generate the model. I use this software for all our airflownetwork models, though I usually export the IDF at a geometry and network state and finish it with other editors. That said, it is a complex process that is not as simple as Mark makes it look. Geometry errors can creep into the model and thwart Mark’s Python code. Good luck�

Ned Lyon, P.E. (MA, WV) Staff Consultant

SIMPSON GUMPERTZ & HEGER 781.907.9000 main 781.907.9350 direct 617.285.2162 mobile 781.907.9009 fax www.sgh.com Send Files

From: EnergyPlus_Support@yahoogroups.com [mailto:EnergyPlus_Support@yahoogroups.com] Sent: Thursday, December 08, 2016 12:20 PM To: EnergyPlus_Support@yahoogroups.com Subject: Re: [EnergyPlus_Support] Re: Need help for Naturally Ventilated Model

I'm sorry, I cannot. All I can suggest is to look at the example files that come installed with E+ and to read the documentation. You also might consider posting your question on unmethours.com

On Thu, Dec 8, 2016 at 11:46 AM, bhavana patil ana5patil@xxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@yahoogroups.com> wrote:

Hi,

Thanks for the reply. Can you please suggest me good resource to learn air flow network

method? I am reading InputOutputReference document. I will really appreciate.

From: "allinson_louis@xxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@yahoogroups.com> To: EnergyPlus_Support@yahoogroups.com Sent: Thursday, December 8, 2016 3:56 PM Subject: [EnergyPlus_Support] Re: Need help for Naturally Ventilated Model

Hi

No you cannot assume 3 ACH. Natural ventilation airflow is dependent on buoyancy driven (caused by internal/external temperature difference) and wind driven. These vary transiently and therefore you will not be delivering a constant ventilation rate, even if you are controlling the vent.

ideally you want to use the airflow network to model airlfow through the windows. You also want to then control the window openings such that you deliver the necessary airflow for IAQ (CIBSE guide B recommends 10l/s/person) when occupied and the sufficient airflow to mitigate overheating.

i suggest that you read section Group - airflow network in the inputoutput document

you could also use an interface like DesignBuilder and read their help files on modelling ventilation through a window

kind regards