[Equest-users] Parametric runs and user expressions

[John Aulbach]

Hi Gang:
Got what should be a simple questions for the gurus..
I have a building which has two water cooled chillers on the first 4 floors. I also have about 30 floors of water cooled DX units. I have a cooling tower and condenser loop set up for the 1st four floors. I am having trouble setting up the water cooled loop for the 30 floors of DX units. 
Can anyone give me a simple example?
Thanks.
John R. Aulbach, PE 

     On Tuesday, February 24, 2015 8:15 AM, David Reddy <david at 360-analytics.com> wrote:
   

   Hi Julien,
 
 I am pretty sure you can't use an expression to set a global parameter; they are limited to being numeric or string (symbol) values.
 
 Unless I am mistaken on what you are after, you can change the values of global parameters in parametric runs; see below for an example.
 
 
 
 To my knowledge, no, you can't reset or restore defaults using parametric runs, but I can't say I've ever investigated this.  You can use expressions that are dependent on a global parameters to set a keyword value to unused or no_default. For example:
 
 {if(#pa("901 HVAC Flag") ==1)
 then 45
 else unused
 endif}
 
 -David
 
 
 On 2/24/2015 6:48 AM, Julien Marrec wrote:
  
      Hi,
 
  Is there a way to implement the following::
 
  - Use a user expression to set a global parameter's value?
  ex: define a parameter which refers to another one: {#PA("GPM_DHW")*500*65/1000000} 
 - Use a user expression in a parametric run component?
 Ex: I would like to set one keyword to refer to a global parameter
 
 
  - In parametric runs, reset values to be default values? Or at least specify the "unused" keyword?
  
  Thanks,
  Julien
  
  Side note: this is pretty weird, but if you have a UVT with HEAT SOURCE being electricity, it stills include some furnace losses, exactly 800 BTU/H (on your fuel meter) which is the DOE default.
 I found this because I've got one example where I have a UVT which Heat source is a furnace in my baseline, and it's actually electric in my proposed model.
 In my baseline, I have defined a user default for the FURNACE-AUX to be 0 BTU/H (no pilot light consumption). This 0 BTU/H value stays once I change heat source to electricity, and gives me a lower gas consumption that I would get if I manually restore FURNACE-AUX to be DOE default (which displays "n/a")).
 
 
  
 
        --
 Julien Marrec, EBCP, BPI MFBA
 Energy&Sustainability Engineer
 T: +33 6 95 14 42 13
 
 LinkedIn (en) : www.linkedin.com/in/julienmarrec
 LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr
            
  
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