[BLDG-SIM] eQUEST warning messages: HSUPPLY, DHW Loop Pump, CURINV

[Andy McNamara]

I am modeling a building in eQUEST with the following HVAC system types:
PTAC, UVT, MZS, PMZS.  The building is situated in New York City, where code
ventilation requirements for the baseline model require exhaust rates
roughly triple ASHRAE 62 guidelines (those requirements will be changing
shortly).  It is a 15 story multifamily building comprised of 5 shells due
to different floor shapes and zoning patterns.  I am having difficulty
understanding three of the warning messages and thought I would see if other
have experienced/solved these problems before.  Thanks in advance!

1)  I am pretty sure this warning message pertains to the MZS or PMZS
because they are the only two air-side systems with HSUPPLY specified in the
INP file.

**WARNING**********************************************************************

             User-specified HSUPPLY-CFM is larger than
             available return air.  Heating capacity may
             be inadequate.
I checked the BEPS report and it shows that
"PERCENT OF HOURS ANY SYSTEM ZONE OUTSIDE OF THROTTLING RANGE = 86.0
PERCENT OF HOURS ANY PLANT LOAD NOT SATISFIED                =  0.0"

2)  I tried increasing the "Pump Head" under "Domestic Water
Heater/Attachments" in the DDI from the default of 1 to several other
values, but the warning message always spits back a number that is 5 ft
greater than whatever I enter under "Pump Head".  E.g., I enter Pump Head =
100, it spits back a loop head of 105 in the warning message.
 **WARNING**********************************************************************
             Pump: DHW Loop Pump                    has a user-specified
head
             of         1. feet, but the loop head is       6. feet.

3)  Per a recommendation from Mike Tillou on the BLDG-SIM archive, I tried
changing all curves in the model to "default", but that did not remove the
following error message (which repeats for literally hundreds of pages).
CURINV: No real root for CURVE:
 1  1.353483  0.015932 -0.369414  0.000000  0.000000  0.000000
CURINV: No real root for CURVE:
 1  1.353483  0.015932 -0.369414  0.000000  0.000000  0.000000
CURINV: No real root for CURVE:
 1  1.353483  0.015932 -0.369414  0.000000  0.000000  0.000000


(Background):
Even though I think I've figured out the source of this warning message, I
thought I'd include it in case it's relevant to understanding the warning
messages above.

This warning is coming from the exhaust rates being specified higher than
outdoor air intake rates.
**WARNING**********************************************************************
             ZONE EL1 ESE Perim Zn ( G.ESE1)        in SYSTEM EL1 Sys1
(PTAC) (G.ESE1)
             has unused EXHAUST-CFM specified.
             This has been converted to outside air.

Thank you so much!  Looking forward to hearing back from those with
thoughts/insights/experiences on this.

Best,
Andy

-- 
****************************************************
Andrew McNamara, LEED AP
Bright Power, Inc.
43 W. 33rd St.
Suite 302
New York, NY 10001
p. 212.803.5868
f. 866.379.8026
c. 917.974.4499
amcnamara at brightpower.biz
www.brightpower.biz


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