Glazing switch in eQUEST, based on hour of the year

asked 2014-09-26 08:50:10 -0500

CJ
116 ●4

updated 2014-09-26 12:23:19 -0500

4675 ●9 ●17 http://bigladdersoftware.com/

I am working on a study project, and looking for ways to model glazing switch in eQUEST explicitly, meaning, forcing eQUEST to do one of the following:

Option 1: Switch GLASS-TYPE (4 available) based on the hour of the year, and not use eQUEST's built-in glazing switch functionality.

Option 2: Use the Layer-By-Layer specification method, and switch one layer based on the hour of the year.

I imagine that Option 1 is achievable with a user expression input for GLASS-TYPE, something along the lines of:

Hour 1: "Glass A", Hour 2: "Glass B" ... Hour 8760: "Glass D"

For Option 2, we would also need a similar user expression input for the window layer being switched (such as Hour 1: Layer 1...Hour 8760: Layer 4).

Part of what I am trying to look at is the simulation runtimes in these options, besides the effect on annual results.

I'd really appreciate if someone could help with writing user expressions for these 2 options. Once I have the format/s for them, I can automate it quickly in Excel and then back into eQUEST.

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answered 2014-09-26 10:18:47 -0500

yongqingzhao

939 ●5 ●10

updated 2014-09-27 06:26:12 -0500

Julien Marrec

29032 ●85 ●74 http://www.effibem.com/

The two options cannot be achieved with expression input for glazings because the expression input cannot make the value of keywords vary hourly. But in eQuest, glazing can be switched based on outside dry-bulb temperature, daylight illuminance, space load, intensity of solar radiation incident on the glazing and so on. It can be set in the blind/drapes-switching tab.

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True. I am aware of eQUEST's native glazing switch capability based on the criteria you listed. But if you had to vary an eQUEST input by the hour like I described, how would you? I am open to ideas beyond the 2 options I could think of.

Thanks for responding.

CJ ( 2014-09-26 11:23:22 -0500 )edit

@CJ I moved your response to the comments, since it was not an answer.

Neal Kruis ( 2014-09-26 12:22:48 -0500 )edit

Thanks Neal. I see how this works now.

CJ ( 2014-09-26 13:42:01 -0500 )edit

Okay, turns out you cannot have hourly values in a user expression. Exploring the option of using an 8760 shading schedule as a workaround to model this.

CJ ( 2014-09-26 16:10:16 -0500 )edit

@CJ I think that is the way to go. You're probably familiar with Rocky Moutain Institute's EMIT, but in case you're not, this will allow you to easily export an excel column to a proper DOE2-format 8760 hourly schedule you can just paste in your .inp of use the "import" function in eQuest.

Julien Marrec ( 2014-09-27 06:24:18 -0500 )edit

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answered 2014-09-26 20:22:05 -0500

Joe Huang
2712 ●4 ●13

Speaking mainly from my experience with DOE-2.1E, I don't think any version of DOE-2 allows for dynamic switching of a building envelope component. With simple windows defined by U and SC (SHGC), it is possible to add a SHADING-SCHEDULE and a CONDUCTANCE-SCHEDULE that can vary however you want (in 2.1E you could reference them with a FUNCTION, and I presume in DOE-2.2/2.3 with an Expression), but I think of that more as modeling drapes and shade screens and not as switching the windows themselves. The other thing to keep in mind is that the thermal behavior of the zone, i.e., its WEIGHTING-FACTOR, will always be constant. If the glazing area is limited, i.e., if the WWR is less than 20, that's not too bad, but if the WWR is large your results will be questionable. That was a problem I encountered many years ago when DOE wanted LBNL to model attached greenhouses with movable insulation at night.

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There is significant difference bettween input expression and input FUNCTION. FUNTION in DOE2.1e can modify Load and HVAC calculation.But The DOE2.2 utilizes expressions only in order to provide more intelligent defaulting(An expression allows the value of a keyword to dynamically default according to the value of another keyword, or a parameter).So the expression can not modify Load and HVAC calculation.And the input FUNCTION feature in DOE2.2 is not implemented.

yongqingzhao ( 2014-09-26 23:43:54 -0500 )edit

Thanks for reminding me about the difference between DOE-2.1E Functions and DOE-2.2/2.3 Expressions. Now that I think of it, 2.2/2.3 Expressions are more like 2.1E Macros than 2.1E Functions in that they operate at the level of the input file, whereas Functions reaches in and modifies the calculations within the code. As far as manipulating a shading or conductance schedule, that's probably doable using an Expression or a Macro as long as it doesn't require something that's calculated during the simulation. I was thinking of a Function I used to model the shading from roller blinds by changing the Shading Coefficient depending on the incident solar angle.

Joe Huang ( 2014-09-27 01:55:28 -0500 )edit

Yeah,your way of manipulating a shading or conductance schedule is doable.But I am very curious why input FUNCTION is not implemented in DOE2.2/2.3.The capacity of DOE2 is greatly weakened!

yongqingzhao ( 2014-09-27 02:17:24 -0500 )edit

There are a number of DOE-2 users, including me, who would like to see FUNCTION implemented in DOE-2.2/2.3. It's a great way to tweak and customize the program without the burden of recompiling the code and proliferating divergent versions of the same basic program.

Joe Huang ( 2014-09-29 11:35:41 -0500 )edit

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