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2019-08-08 10:22:38 -0500 marked best answer OpenStudio/EnergyPlus Thermal Zone Outdoor Air Balance with Exhaust Fan Only and 100% Outside Air System

I am attempting to model an outdoor rest station with two large bathrooms. Based on ASHRAE 62.1 the restrooms have an exhaust airflow requirement of 70 cfm/toilet. Additionally, I am modulating the CFM by the occupancy schedule since there is very low occupancy during the winter.

In OpenStudio, I am using a Fan:ZoneExhaust object in each thermal zone with the Maximum Flow Rate option matching the CFM for the number of toilets. Using a 100% outside air system, I was hoping that the system would supply the correct amount of ventilation air to the space to supplement the exhausted air, without specifying any ventilation requirements.

However, in the error report, I am receiving the message:

  ** Warning ** GetOAControllerInputs: Controller:MechanicalVentilation="CONTROLLER MECHANICAL VENTILATION 1
  **   ~~~   ** Cannot locate a matching DesignSpecification:OutdoorAir object for Zone="THERMAL ZONE: 1 FEMALE RESTROOM".
  **   ~~~   ** Using default OA of 0.00944 m3/s-person and 0.0 m3/s-m2.

and

   ** Severe  ** Controller:MechanicalVentilation="CONTROLLER MECHANICAL VENTILATION 1", Design Specification Outdoor Air Object Name blank
   **   ~~~   ** For Zone="THERMAL ZONE: 2 MALE RESTROOM".
   **   ~~~   ** This field either needs to be filled in in this object or Sizing:Zone object.
   **   ~~~   ** For this run, default values for these fields will be used.

Which appears to be applying a Design Specified Outdoor Air that doesn't really balance with the Fan:ZoneExhaust object.

My question is, using the Fan:ZoneExhaust object with the Decoupled mode and Unbalanced (as seen in the documentation), is my fan being properly balanced with the 100% OA packaged rooftop system?

Should I specify a 0 DesignSpecification:OutdoorAir or will this incorrectly size my system?

What is the best method to balance my ventilation and exhaust flowrates for these spaces?

What about when I add energy recovery ventilation? How do I force the exhaust air back to my central system while keeping the correct ventilation requirements for the restroom?

2019-07-17 07:58:12 -0500 commented answer E+ vs. IES: Loads Results comparison

Hi @lutinfr, can you please elaborate how I can change my calculation method to ASHRAE in IESVE?

2019-06-11 13:58:21 -0500 commented answer FMU Dymola variable input

Hi Giorgio, troubleshooting that kind of problem becomes more challenging without additional information. I would recomm

2019-06-06 08:44:59 -0500 edited answer FMU Dymola variable input

I have done this with other systems and found the best method is through the use of a plant loop with a PlantComponent:T

2019-06-06 08:44:30 -0500 answered a question FMU Dymola variable input

I have done this with other systems and found the best method is through the use of a plant loop with a PlantComponent:T

2019-06-04 01:08:41 -0500 marked best answer FMU Export of Python Code or Python Interface with FMI Standard for Use in EnergyPlus Co-Simulation

My research group has developed python code for a new building component that we would like to co-simulate with EnergyPlus. For reuseability and market impact we would like this connection to be as easy as possible for inexperienced users and believe packing the model using the Function Mockup Interface Standard (FMI) to be the best option.

We have explored JModelica to test other Functional Mockup Units (FMUs) but found that it does not do FMU export of Python code for model exchange or co-simulation.

I was curious if there any methods for packaging python code as an FMU? If there is not, is there another way of linking Python to the FMI standard or connecting it to a building energy software like EnergyPlus?

The alternative to this would be exporting the building energy model as an FMU and import into modelica/jmodelica or using BCVTB. Although this would work for us we worry it would make it too difficult for inexperienced individuals to use our tool.

2019-04-29 14:32:04 -0500 marked best answer Multizone Packaged Rooftop Heat Pump for ASHRAE Baseline

Hello Modeling Community,

I have set up a small building model (<2300m2) with zones for each of the interior rooms. After setting up the geometry I wanted to configure a baseline following ASHRAE 90.1-2010, which recommends a Packaged Rooftop Heat Pump system. I set up a Packaged Rooftop Heat Pump system in OpenStudio, replacing the SingleZone setpoint manager with a Scheduled:DualSetpoint manager. After a lot of head scratching and model iterations I discovered that the EnergyPlus documentation for the HVACTemplate:System:UnitaryHeatPump:AirToAir states:

This system may serve one or more HVACTemplate:Zone:Unitary objects. If this system serves more than one zone, only one zone is specified as the control zone.

Which may explain why my system was not properly autosizing for the entire building.

So my questions are:

  1. How do I setup a packaged rooftop heat pump system for a multizone building?
  2. Can I use the packaged rooftop heat pump system as a preheater/precooler and at the zone level use heating and cooling diffusers? Does this still follow ASHRAE 90.1-2010?
  3. Is it possible to autosize a packaged rooftop heat pump system for a building with multiple zones?
  4. Are there alternative systems I could consider for a baseline?

Thank you for your time,

Justin

2019-03-22 09:04:40 -0500 received badge  Self-Learner (source)
2019-03-22 06:23:27 -0500 commented answer OpenStudio User Interface Scaling Problems (Very Small Buttons)

@Aaron Boranian, thank you for the suggestion. I have posted my answer with additional details.

2019-03-22 06:22:27 -0500 answered a question OpenStudio User Interface Scaling Problems (Very Small Buttons)

After following @Aaron Boranian's answer I discovered an easier work around. Find either your OpenStudio shortcut or

2019-03-21 17:33:48 -0500 commented answer OpenStudio User Interface Scaling Problems (Very Small Buttons)

This issue was more easily solved by changing the compatibility options in windows under properties and change DPI setti

2019-03-21 17:33:00 -0500 commented answer OpenStudio User Interface Scaling Problems (Very Small Buttons)

This issue was more easily solved by changing the compatibility options in windows. See this image.

2019-02-15 13:40:46 -0500 commented answer Energyplus FMU in Pyfmi

@mfath in addition to the IDF file that Thierry asked for, can you post an image/script of the command line you are usin

2019-02-10 08:43:04 -0500 answered a question Energyplus FMU in Pyfmi

How are you compiling the EnergyPlus file as an FMU? Are you using the EnergyPlusToFMU tool provided by LBL? If not, I

2019-02-07 16:27:42 -0500 commented answer OpenStudio User Interface Scaling Problems (Very Small Buttons)

In the comments to the above article, the author notes that Windows 10 has built the fix in by right clicking the applic

2019-02-07 16:27:16 -0500 commented answer OpenStudio User Interface Scaling Problems (Very Small Buttons)

In the comments to the above article, the author notes that WIndows 10 has built the fix in by right clicking > Prope

2019-02-07 15:12:02 -0500 commented answer OpenStudio User Interface Scaling Problems (Very Small Buttons)

Aaron, thank you for the response. That worked like a charm!

2019-02-07 15:11:39 -0500 marked best answer OpenStudio User Interface Scaling Problems (Very Small Buttons)

I have just started using OpenStudio on a 4k monitor and found that the graphical user interface elements do not appear to be scaling correctly. All of the buttons are super tiny and hard to click.

Is there a setting or configuration file I can change to scale the interface elements?

2019-02-07 08:50:37 -0500 commented answer OpenStudio User Interface Scaling Problems (Very Small Buttons)

Thank you for your suggestion. I would hate to use a lower resolution just so that OpenStudio displays correctly. I hope

2019-02-07 08:02:57 -0500 asked a question OpenStudio User Interface Scaling Problems (Very Small Buttons)

OpenStudio User Interface Scaling Problems (Very Small Buttons) I have just started using OpenStudio on a 4k monitor and

2018-12-20 13:34:14 -0500 commented answer What is the best way to use Excel to work with IDF files?

I was just looking into using Pandas to read my EP output files the other day. However, I had trouble parsing the very l

2018-12-20 13:33:52 -0500 commented answer What is the best way to use Excel to work with IDF files?

@Lyle K, that is a very good suggestion. Thank you, I will start there!

2018-12-20 09:37:55 -0500 commented answer What is the best way to use Excel to work with IDF files?

I was just looking into using Pandas to read my Python output files the other day. However, I had trouble parsing the ve

2018-12-06 15:08:22 -0500 received badge  Popular Question (source)
2018-08-07 10:51:59 -0500 commented answer OS Error:''For zone: it is not possible to calculate the volume from the surrounding surfaces so either provide the volume value or define all the surfaces to fully enclose the zone.''

@Raghda Derbel You are close but it would be more accurate to sum all the volumes and set that as the volume in the ther

2018-08-07 10:16:01 -0500 commented answer DView Loading Data Extremely Slowly

@anchapin please post the GitHub issue link when you do so that I can post my experience and keep track of the solution.

2018-08-07 08:02:13 -0500 commented answer OS Error:''For zone: it is not possible to calculate the volume from the surrounding surfaces so either provide the volume value or define all the surfaces to fully enclose the zone.''

@Raghda Derbel, you will need to define a new thermal zone for each kitchen.

2018-07-31 09:45:41 -0500 marked best answer DView Loading Data Extremely Slowly

OpenStudio now uses DView directly for data visualization instead of ResultsViewer. However, while trying to open data dview takes several minutes (sometimes 15 or more) just to open a small output file. Are there any fixes I can do to that will make this process faster?

In the meantime, I will likely need to use another results viewer because this is too slow.

2018-07-26 17:19:24 -0500 commented answer Best method to define individual space properties

Thank you for your answer. I should really learn Ruby and the OpenStudio SDK. It seems like I could automate a lot of my

2018-07-26 17:18:51 -0500 marked best answer Best method to define individual space properties

I am setting up an OpenStudio model for an architectural project and there are quite a lot of spaces where I have to define unique properties for occupancy and ventilation. More specifically they are labs with fume hoods.

I've defined high level information as space types and placed local properties onto the spaces in the "Spaces" tab. However, the space type definitions remain part of the calculations.

Space Load Properties

Zone Name        |  Floor Area {m2} | # Occupants | Area per Occ {m2/person}| Occ per Area {person/m2}  
THERMAL ZONE: 514 ADV CHEM TL    167.93    25.0           6.70                    0.15

Is there a way to override the space type properties when a local load has been defined in the "Spaces" tab?

What are the best methods and practices when it comes to defining properties for individual spaces in OpenStudio?

I found this old question here but it seems to no longer be relevant with new versions of OpenStudio.

2018-07-24 16:57:51 -0500 edited question Best method to define individual space properties

Best method to define individual space properties I am setting up an OpenStudio model for an architectural project and t