Door U-Value

chonghuil · Posts: 6

Hello,
Just run into another question:
How to set up the swinging door U-value to 0.7?
I tried "set U-value", but didn't allow me to.

BTW, is there an easier way to setup baseline model for LEED?
Do you have such an ASHRAE 2007 (only 1999 ASHRAE code is available) templet?
Or you have to set up every baseline change yourself?

Thanks.
Chonghui

jean marais · Posts: 93

There are at the minute no templates for this Sad

. That doesn't mean that there won't be in the future. Setting up a door U-value this high is not possible with the "door" object (see page 194 of the E+ Input Output Ref.) in energy plus, as far as I can tell, because it uses normal construction types which I think max out at U 3.845 W/m2K. I also needed a U of 3.975, but I'm leaving it at 3.845 because it's more conservative and fairly close enough.

I can suggest the following work around:

The "window" object can however handle "WindowMaterial:SimpleGlazingSystem" construction type where one can specify the SHGC and U-value. DB supports this input (check the glazing type under the openings tab. where you can set up an ASHRAE glazing type that has the SHGC and U-value you need). This means you could consider using a glazing as a door by setting the solar properies as it would be for your door.

I don't know how else to do it. I have the same issues and have not yet implemented this.

Anybody else?

parag.karanjkar · Posts: 37

I work with the glazing elements as a substitute for materials that have high U-values.
As you said Jean, I use the same work around.

However, I faced a problem further.
Trying to follow certain guideline U-values for inclined skylights, I required entering U-values in the range of 8-11.
DesignBuilder calculates the U-value and SHGC with certain ambient conditions. For the U-Value calculation, the guidelines I follow recommend entirely different weather conditions to compute the U-value and SHGC. (I suppose Indian Climate versus UK climate makes a lot of difference in the U-value calculation)

Therefore, DB allows U - values for a window (any entity) as high as 6.5 or so. The same material will have a different U-value, SHGC through a different calculation method or different ambient variable values.

How do you think one should go around this?

jean marais · Posts: 93

From what I can remember the e+ U-value calculation for windows was maxing out at 6.5. In that project I needed 6.81 and at the time the direct input method was not available through DB and was only released in e+ half way through the project. I just stuck to 6.5 as it was conservative in any event.

I've not tried to enter values higher than 6.5 in the direct input way and can't say if it works or how e+ is going around using these values. Sorry.

Theoretically, any glazing material can now also be specified directly with the assembly U-value and SHGC for window objects. Are you using the skylight objects in e+ that are not yet supported in DB, or are you using normal window objects in DB for skylights?

parag.karanjkar · Posts: 37

I was trying to use those in DB - not in E+.
There is no direct input yet for glazing material though.

jean marais · Posts: 93

What version are you using. The latest release 2.2? You are right, but the beta releases have supported it since 2.3.4.002 (21/07/10). It will obviously be released with the 2.3 version. Until then you could either use the beta versions (with caution, and regularly check the revision history (http://www.designbuilder.co.uk/content/view/28/43/) so that you can see if there are errors that crop up in the beta you are working in and if it effects your outcomes; Or output the idf file and edit it, thereafter running the simulation using e+. You can always read the results back into DB (as long as the geometry doesn't change, in which case new zone ids are created). As a tip, always save the DB file into the same folder as where you output the e+ idf to, and also output a csv file which tracks the zone IDs to the zone names you use in DB in the same folder. If you do a new simulation repeat the process into a new folder. Don't change the DB file that you saved with the output idf. Instead save it as a seperate working file so that the zone ids always remain compatible.

This probably sound a bit confusing. See how you get on and then let us know.

jean marais · Posts: 93

** Severe ** Out of range value Numeric Field#1 (U-Factor), value=7.38000, range={>0 and <=7}, in WINDOWMATERIAL:SIMPLEGLAZINGSYSTEM=SIMPLE 1003

It looks like the U values max out at 7, even for the simple input

parag.karanjkar · Posts: 37

Hey,
I am using 2.3.5.011
however Andy mentioned that simple u-value for glazing will be implemented from 2.3.5.015

and btw, thanks for the very useful advice you provided here !

parag.karanjkar · Posts: 37

I use DB itself to track the zone ids.
In the 'Edit --> Options --> Simulation Options' I can see the zone id used in the E+ calculations.
The CSV file you output -- is it better to copy Zone Ids from there ? Excel to Excel ?

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