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No change in Zone Temperature before/after "Wind and Stack Open Area" measure

asked 2017-07-23 12:12:46 -0500

archsoso gravatar image

updated 2017-08-05 07:27:35 -0500

I'm using openstudio 1.11.1 and E+ 8-5-0.

My building has many windows with different dimensions and I want to make them operable.

I used Add Wind and Stack Open Area measure and set the dimensions of the windows then I ran the model.

However, I obtained the same results for the temperature as without "Add Wind and Stack Open Area", i.e., same results as when the windows are fixed type. Is that possible?

I think I may have a problem with the determination of the open area and average window height values. Any advice to input correct values?

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Is the open area in the measure "Wind and Stack Open Area" means the total area of of window in meter square (width*height)? what about the window height, is it in meter or meter square? @David Goldwasser

archsoso gravatar image archsoso  ( 2017-07-24 00:25:23 -0500 )edit

Please include a link to said Measure... Are you talking about Add Wind and Stack Open Area?

It would also be great if you could proof the spelling in your posts too, and no need for extra punctuation (eg: one "!" is more than enough). Note that all recent internet browsers allow you to use a Spell Checker, and you can add an English dictionary for that. I did it for you for this time, please review.

Julien Marrec gravatar image Julien Marrec  ( 2017-07-24 03:36:50 -0500 )edit

Ok, now that the uninteresting stuff is out of the way, let's get back to your question. There's a ton of reasons why it wouldn't produce different temperatures... The first one would be that the measure wasn't configured properly or didn't run (eg: you might have set the Min/Max temps such as it would never occur during the simulation). There's no way to tell what the measure did or didn't do in the current form of your question. Can you at least post a resulting ZoneVentilation:WindandStackOpenArea from the E+ IDF file generated after you ran the measure?

Julien Marrec gravatar image Julien Marrec  ( 2017-07-24 03:45:09 -0500 )edit

I think I have problem with determination the open area and average window height values. since I set the Min/Max temperature according to the temperature values that obtained for the fixed window results. Any advice to input correct values for open area and average window height?

archsoso gravatar image archsoso  ( 2017-07-24 04:11:28 -0500 )edit

I just checked the IDF file I found no results for ZoneVentilation:WindandStackOpenArea.

archsoso gravatar image archsoso  ( 2017-07-24 04:23:02 -0500 )edit

2 Answers

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answered 2017-07-26 17:11:18 -0500

updated 2017-07-26 19:33:29 -0500

  1. That measure is fairly simple: it takes the input arguments you give it and it creates ZoneVentilation:WindandStackOpenArea input objects with those argument values. For the meaning of those input values, you should read the documentation for that object. However, the measure uses the 'Average Window Height (m2)' argument as the value for the input field "Height Difference", which should not have units of m2. Lesson: measures on BCL are not perfect, and it _really_ helps to be able to read and understand what they do.

  2. Looking at the measure code, it appears that if you are not finding any ZoneVentilation:WindandStackOpenArea objects in your idf after running the measure, it _most likely_ means your input model does not contain any thermal zones, or the walls in your model do not have exterior boundary condition set to 'Outdoors'. The measure loops though all BuildingSurface:Detailed objects and finds the ones where Surface Type = "Wall" and Outside Boundary Condition = "Outdoors". It then finds the field that references the zone name and puts those names into an array, then loops through that array to create one WindandStackOpenArea object per zone. So something is clearly going wrong in that process.

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answered 2018-03-12 18:09:33 -0500

The older version of the Add Wind and Stack Open Area applied a default 0.7 m2 operable window area to any zone with an exterior wall, regardless of whether it had windows. I've updated the measure and it now asks for an operable window construction and calculates window area directly from the window geometry.

Note that while OpenStudio subsurfaces can have a FixedWindow orOperableWindow subsurface type, this distinction does not carry into EnergyPlus which treats all windows as a FenestrationSurface:Detailed. This EnergyPlus object does not have a subsurface type, so you need to specify a construction to let the measure know which windows are operable.

Measure Updates:

  • Changed inputs to have user selected an open area fraction schedule
  • Changed inputs to have user select an operable window construction
  • Measure now adds ZoneVentilation:WindandStackOpenArea objects per window instead of per zone
  • Measure now calculates operable area based on window geometry
  • Measure now calculates effective angle based on the surface normal of a given window
  • Measure now calculates height difference to neutral pressure level as half window height
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Asked: 2017-07-23 12:12:46 -0500

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Last updated: Mar 12 '18