Hello,
It would be greatly appreciated if someone would provide some advice on
how to create a user input expression. In order to easily manipulate
the percent glass of a building in the detailed interface, I would like
to create an expression that sets window width based on a global
parameter for percent glass I created. To accomplish this, I right
click on the width input cell and select "Edit/View User Expression...",
then enter the following code I came up with based on what I have been
reading in the DOE-2 help files.
(PARENT( EXTERIOR-WALL:HEIGHT ) *
PARENT( EXTERIOR-WALL:WIDTH ) *
PARAMETER("East Wall Percent Glass")) /
LOCAL( HEIGHT )
This does not work. Below are the errors that the above expression
generate.
Expression Parsing Error: Invalid BDL Keyword Function Argument
'EXTERIOR-WALL:HEIGHT'
Expression Parsing Error: Invalid BDL Keyword Function Argument
'EXTERIOR-WALL:HEIGHT'
Expression Parsing Error: Invalid BDL Keyword Function Argument
'EXTERIOR-WALL:HEIGHT'
I have tried several variations of this expression with no luck.
Thank you in advance for any advice you can provide.
Jeremy
To access a parent parameter use the command #P. To access a local
parameter use the command #L. Also, global parameters are referenced by
the #PA command. The errors you describe are because the name of the
parameter you are trying to reference isn't EXTERIOR-WALL:HEIGHT, it's
just HEIGHT.
Try this:
{#P("HEIGHT")*#P("WIDTH")*#PA("East Wall Percent Glass")/#L("HEIGHT")}
If that doesn't work let me know, as I just typed that up on the fly.
Robby Oylear
Jeremy--
check out Brandon Nichols's page below. Half way down that post he
describes how to do write expressions for glazing. You can add a
glazing % global parameter to his code and it should work.
http://elcca-exchange.blogspot.com/2006/12/equest-detailed-editor-notes.html
Steve Mignogna
Thank you! It works great now.
I have another question if you have minute to reply. Can I reference a
parameter that is not a global, parent, or local parameter in my
expression? For example, can I include the height of the plenum wall in
the wall area calculation?
Something like:
((PARENT( "HEIGHT" )+( EL1 East Wall (G.7.E13)("HEIGHT"))) *
PARENT( "WIDTH" ) *
PARAMETER("East Wall Percent Glass")) /
LOCAL( "HEIGHT" )
Dear all,
While writing an expression for window frame width of curtain walls in
eQuest 3.61, I am getting 'Expression parsing error' saying the user
expression is too long. The expression used is-
default :
PARENT("WIDTH")*PARENT("HEIGHT")*0.0464/(PARENT("WIDTH")+PARENT("HEIGHT"))
How should I modify or change it?
Are there provisions for creating local variable by arithmetic operation on
present variables? For example, the length of this expression can be reduced
, if I calculate perimeter of parent wall first and use that value directly
in the expression.
Any help will be appreciated.
Regards,
Prabhat Barnwal
I just pasted the expression into one of my projects and it worked fine.
You may just need to allow the expression to go onto two lines like so:
PARENT("WIDTH")*PARENT("HEIGHT")*0.0464/
(PARENT("WIDTH")+PARENT("HEIGHT"))
Another way to shorten the expression is use #P instead of writing out
"Parent"
#P("WIDTH")*#P("HEIGHT")*0.0464/(#P("WIDTH")+#P("HEIGHT"))
Hope this helps
--
Karen
I have a mechanical room that is conditioned to 95 in cooling through
exhaust fans and heated to 65 with unit heaters.
Do the exhaust fans constitute as a cooling system? The system would
need to provide a sensible capacity of 5 btu/h*ft2 for the mech room to
be considered to be a cooled space, which I have not yet calculated.
The reason I as is that if these exhaust fans are not considered a
cooling system then the baseline cooling system will need to be modeled
to complete an accurate LEED model.
Any suggestions?
Timothy Howe, MS, LEED(r) AP
Does anyone know if it's possible to call a simulation result as a variable
in an expression? I would like use the Supply CFM of a system, as sized by
eQUEST (in a previous run) and shown on SV-A, in the expression for Outside
Air Ratio, Minimum Flow Ratio, etc.
Thanks,
Jay Keazer, EI
Hello!
Does anyone know why eQuest/DOE2.2 is not included in the list of qualified
software that can be used to apply for EPAct 2005 Federal Tax incentives?
The current list includes DOE-2.1-E and DOE-2.1E-JJH as well as Energy Plus,
VisualDOE, Trace 7000, and others.
It seems like eQuest is one of the more popular modeling software packages
used for LEED energy modeling - should I stop using it because DOE2.2 and
eQuest are not registered as qualifying software? If Trace 7000 and
VisualDOE can be qualified, eQuest certainly should be.
Thanks,
Eric
Only DOE-2 input keyword values/selections can be referenced by BDL
expressions.
That having been said, you CAN setup a numeric Global Parameter called
"SupplyCFM", set its value manually following a sizing run and then
reference that global param in your BDL expressions. The only downside
here is that you have to manually update this global param each time the
Supply CFM changes in order for your various (dependent) keywords to
adjust to the new CFM value.
- Scott
Hi Prabhat,
I'm glad it worked for you. I have not worked in the user input expression
mode too much either, but did develop a way to calculate what direction a
window is facing and determine glass type based on this info. I'm attaching
the text file with the module and instructions.
I found that the best resource for this is the help file. Once help is
open, under contents go to: Volume 3: Topics --> Building Description
Language --> Keyword Expressions
When learning expressions, start with a very small expression, and try it
out. Try running the file too to make sure there are no run-time errors as
a result of the expression. Once you get a small piece working, add to it
slowly. This will help you figure out exactly where your errors are.
Good luck! I hope I can help with future questions.
--
Karen
Tim
My thoughts on this would be that your main system should be sized to
provide the fresh air at your cooling temperature to replace the air
rejected by the exhaust, and you will probably find this is happening
unless your space is negatively pressurized.
Gary Chatfield