[Equest-users] Appendix G Baseline Systems 6 and 8 - supply air temperature controls?
Robby Oylear
robbyoylear at gmail.com
Thu Nov 21 13:17:48 PST 2013
I'm not sure I follow your interpretation on G3.1.3.14. The supply air
temperature setpoint is constant at the design condition regardless of
whether you reset airflow or temperature first. At the design condition
there will be no reset occurring because you're by definition, at design.
I've always interpreted that whole section of G3.1.3.14 to be referring to
the terminal unit fans only.
TEMPERATURE-FIRST makes the most sense to me for accomplishing G3.1.3.12,
but I may be biased as in a marine climate resetting temperature up
increases economizer hours dramatically.
-Robby
On Thu, Nov 21, 2013 at 10:28 AM, Bishop, Bill <bbishop at pathfinder-ea.com>wrote:
> I also created an input file template for System 6 which could be used
> for System 8 with some modification. Comments/mods are welcomed.
>
>
>
> $ *********************************************************
>
> $ ** **
>
> $ ** Performance Curves **
>
> $ ** **
>
> $ *********************************************************
>
>
>
> "G3.1.3.15 VAV Fan Curve fPLR" = CURVE-FIT
>
> TYPE = CUBIC
>
> INPUT-TYPE = COEFFICIENTS
>
> COEFFICIENTS = ( 0.0013, 0.147, 0.9506, -0.0998 )
>
> ..
>
>
>
>
>
> $ *********************************************************
>
> $ ** **
>
> $ ** HVAC Systems / Zones **
>
> $ ** **
>
> $ *********************************************************
>
>
>
> SET-DEFAULT FOR ZONE
>
> TYPE = CONDITIONED
>
> MIN-FLOW-RATIO = 0.3 $ Per G3.1.3.14
>
> ZONE-FAN-KW/FLOW = 0.00035 $ Per G3.1.3.14
>
> ZONE-FAN-RATIO = 0.5 $ Per G3.1.3.14
>
> TERMINAL-TYPE = PARALLEL-PIU $ For all zones served by Sys 6 or Sys
> 8
>
> ..
>
>
>
> SET-DEFAULT FOR SYSTEM
>
> TYPE = PIU $ For Baseline System 6 and System 8
>
> HEAT-SOURCE = ELECTRIC $ Per Table G3.1.1B and User's Manual
> p.G-23
>
> ZONE-HEAT-SOURCE = ELECTRIC $ Per Table G3.1.1B and User's Manual
> p.G-23
>
> HEAT-SIZING-RATI = 1.25 $ Per G3.1.2.2
>
> COOL-SIZING-RATI = 1.15 $ Per G3.1.2.2
>
> COOL-SOURCE = ELEC-DX $ Per Table G3.1.1B
>
> MAX-SUPPLY-T = 92 $ Per G3.1.2.8 (20F above room heat
> T-Stat
>
> HEAT-SET-T = 62 $ = COOL-MAX-RESET-T plus 1F
>
> MIN-SUPPLY-T = 56 $ Per G3.1.2.8 (20F below room cool
> T-Stat
>
> COOL-CONTROL = WARMEST $ Per G3.1.3.12
>
> ECONO-LIMIT-T = 70 $ Per G3.1.2.7 and Table G3.1.2.6B by
> climate zone
>
> ECONO-LOCKOUT = YES $ (Seems like a reasonable baseline
> default)
>
> COOL-MIN-RESET-T = 56 $ = MIN-SUPPLY-T
>
> RESET-PRIORITY = AIRFLOW-FIRST $ Per G3.1.3.12 and G3.1.3.14
>
> COOL-MAX-RESET-T = 61 $ Per G3.1.3.12 (5F above MIN-SUPPLY-T)
>
> OA-CONTROL = OA-TEMP $ Per G3.1.2.6 and Table G3.1.2.6A
>
> FAN-CONTROL = FAN-EIR-FPLR $ Per G3.1.3.15
>
> NIGHT-CYCLE-CTRL = CYCLE-ON-ANY $ Per G3.1.2.4
>
> FAN-EIR-FPLR = "G3.1.3.15 VAV Fan Curve fPLR" $ Per G3.1.3.15
>
> REHEAT-DELTA-T = 36 $ = MAX-SUPPLY-T minus MIN-SUPPLY-T
>
> ..
>
>
>
> $ Bill
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Bishop, Bill
> *Sent:* Thursday, November 21, 2013 1:14 PM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] Appendix G Baseline Systems 6 and 8 - supply
> air temperature controls?
>
>
>
> ASHRAE Standard 90.1, G3.1.3.12 requires cooling supply air temperature
> reset for Systems 5 through 8.
>
> G3.1.3.14 requires “supply air temperature setpoint shall be constant at
> the design condition” for Systems 6 and 8.
>
> How should we interpret this and model it in eQUEST (for Systems 6 and 8)?
>
>
>
> If the “design condition” in G3.1.3.14 means “peak design flow rate”, I
> suggest the following cooling control settings:
>
> - COOL-CONTROL = WARMEST
>
> - COOL-MIN-RESET-T = 56 $ (assumes 76F
> cooling T-stat; 56F MIN-SUPPLY-T for 20F difference per G3.1.2.8)
>
> - RESET-PRIORITY = AIRFLOW-FIRST
>
> - COOL-MAX-RESET-T = 61 $ (5F reset per
> G3.1.3.12; assumes 76F cooling T-stat)
>
>
>
> Using a RESET-PRIORITY of “TEMP-FIRST” resets the supply air temperature
> *before* the airflow, which does not satisfy the G3.1.3.14 requirement.
>
> Using a RESET-PRIORITY of “TEMP-FIRST” or “SIMULTANEOUS” does not satisfy
> the G3.1.3.12 requirement, since temperature is reset well before minimum
> cooling load conditions are reached.
>
>
>
> Does anyone have an alternative/additional suggestion or interpretation?
>
>
>
> Thanks,
>
> Bill
>
>
>
> *William Bishop, PE, BEMP, BEAP, LEED AP **|** Pathfinder Engineers &
> Architects LLP*
>
> *Senior Energy Engineer*
>
> [image: webCertified_logo_colorRGB72DPI.jpg]
>
>
>
> 134 South Fitzhugh Street Rochester, NY 14608
>
> T: (585) 325-6004 Ext. 114 F: (585) 325-6005
>
> bbishop at pathfinder-ea.com <wbishop at pathfinder-ea.com>
> www.pathfinder-ea.com
>
> P Sustainability – the forest AND the trees. P
>
>
>
>
>
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