[Equest-users] Parametrics for Multi-family

Thu Apr 14 16:05:41 PDT 2016

Hi Sunayana,

One option to consider for Appendix G & similar contexts is that you can always do two separate models instead of rolling everything into a single model using parametrics.  Pros and cons both ways – but neither approach is “wrong.”

If you would like to push ahead with leveraging parametric runs to build your proposed on top of your baseline (typically I’d be going in the other direction, but the same advice applies), you can effect “autosizing” capacities for one run and “specified” inputs for the other leveraging a combination of input expressions and global parameters.

Example (pictures follow each step for subscribers that don’t receive with formatting):

1.       Set up a global parameter to serve as a “flag” – (tip: descriptive naming is always a good idea):

PARAMETER

   "Specify_CFM"          = 0  ..

2.       Use if/then expressions to switch up a specified capacity vs. no input (“no_def,” resulting in auto-sizing).  This example is intended for a system CFM entry (SUPPY-FLOW):

if(#PA("Specify_CFM")==0)

 then no_def  $ If Flag is off, no specified CFM

  else 1200    $ If Flag is on, specify this CFM

endif

(for this particular example, you would not see anything at the eQuest input box if it’s working correctly – toggling the #PA to something other than 0 should result in a pink input of 1,200 in the eQuest interface)

3.       For your parametric run, add a component which “activates” this #PA flag:

The result: For that parametric run, whatever you entered after “else” in the expression (i.e. 1200) will be used for the system’s SUPPLY-FLOW input.

I’d advise trying the above process a few times to get the hang of the concept, if this is all foreign.  You could modify that expression and use 4 different versions of it in your model for 4 distinct proposed typical system equipment selections, for example.

After this feels comfortable, a few other notes/tips to consider:

·         The expression for step #2 can grow in complexity to  specify different capacities based on other local inputs. 

·         In direct consideration of “summed systems:” Instead of a number (i.e. 1200), an expression can perform simple algebra (i.e. 3*400 or 600+200+400).  This is categorically BETTER practice than doing the same sort of math “on the side,” as you’re documenting how your inputs were determined directly within the model for your own/others’ reference. 

·         Instead of a static result, the expression can also do math incorporating other variables…  Considering the “combined” zones/systems you mentioned electing to use, you could specify CFM (& heating/cooling capacities… etc.) per local unit area to determine “weighted” capacity automatically.  This entered at a zonal level would result in 1.25 CFM/ft2, as an example:  #LR("SPACE","AREA")*1.25.

·         To save more time during inputs and further reduce potential for human error, everything we’re talking about for expressions can also be applied as user-defaults (“user default expressions”).  

Best of luck!

~Nick

------------------------------------------------------------------------------------------------------------------------------

Nick Caton, P.E.

  Senior Energy Engineer
  Energy and Sustainability Services
  North America Operations
  Schneider Electric

D  913.564.6361 
M  785.410.3317 
E  nicholas.caton at schneider-electric.com <mailto:nicholas.caton at schneider-electric.com> 
F  913.564.6380

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Sunayana Jain via Equest-users
Sent: Wednesday, April 13, 2016 4:40 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Parametrics for Multi-family

Hi All,

I have created a baseline model for a large multi-family building. Thermal zones in my model are such that some zones have 10 residential units, some have just 1 unit (corner ones) and likewise.  I am running parametric runs to obtain proposed model. Proposed and baseline residential systems are packaged terminal heat pumps.

I used weighted average to calculate kW/CFM, Cooling and Heating EIR for the proposed  systems and have put them in parametric runs. However, I am not sure how to put CFM and heating and cooling  capacities in parametric as I don’t want to run separate parametric for each thermal zone.

Any suggestions will be appreciated.

Thanks,

Sunayana

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