[Equest-users] Parametric runs and user expressions

Julien Marrec julien.marrec at gmail.com
Wed Feb 25 00:35:38 PST 2015


John,

Even though I'm not a guru I'll give it a shot...

Which type of zone HVAC system are you using for those 30 floors with water
cooled DX?

If you look at the help entry for CONDENSER-TYPE:

WATER-COOLED          The condenser is water cooled. You must attach the
condenser to a CIRCULATION-LOOP of TYPE = CW or WLHP via the CW-LOOP
keyword. For PSZ, PVAVS and PVVT, use of this value indicates that a
water-to-air heat pump (WLHP) is to be modeled.

If you use PSZ, PVAVS and PVVT, you go to Cooling > Condenser, set
CONDENSER-TYPE = WATER-COOLED, then it will allow you to specify the CW
loop you want to use (CW-LOOP).

If you use a PMZ or PTAC, even though you can select CONDENSER-TYPE =
WATER-COOLED, the GUI doesn't let you enter the CW-LOOP. I'm not sure why,
or if forcing it in the INP file achieves the right results. I'll let one
of them guru chime in on that :).



​

Best,
Julien

--
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
<http://www.linkedin.com/in/julienmarrec>

2015-02-25 7:20 GMT+01:00 John Aulbach <jra_sac at yahoo.com>:

> 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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