Fix VAV min flow frac > 1.0 and a bunch of termunitsizing issues related to multiple airloops #6338

mjwitte · 2017-09-21T16:21:02Z

Pull request overview

Addresses VAV design minimum cooling air flow fraction > 1.0 when system adjusts zone flows #6327 to not allow design VAV min flow frac to be >1.0
Fix some places in size single duct to use TermUnitFinalZoneSizing as all terminal units should now in order to see the impact of any DesignSpecification:AirTerminal:Sizing inputs.
And make sure that VAV min flow is at least the MinOA requirement for the terminal unit, even if DesignSpecification:AirTerminal:Sizing sets the cooling flow to zero.
Many changes throughout sizing functions to make sure that scaling of load vs OA or both flow through properly to system sizing.
Move Std 62.1 sizing to use TermUnitFinalZoneSizing.
Remove Std 62.1 system-level scaling of zone-level OA flow rates (Voz).
Report base Voz with no system adjustments for Zone Minimum Outdoor Air Flow Rates reported for zone sizing in eio output "Zone Sizing Information" and table output "HVAC Sizing Summary - Zone Sensible Cooling (and Heating) subtables.
Fix various sizing timing related issues in evap cooler and VRF TUControl.
Engineering Ref changes

10. Review VRF coil sizing report diffs noted below.
11. Later - Additional test files to demonstrate that scaling is working as it should.
12. Addresses part of Additional Terminal Unit Sizing Issues #6481 (Change remaining Coil:Heating:Gas to Fuel plus cleanups on new coil sizing reports #6500 addresses the rest)

Explanation of Diffs

5ZoneAirCooledWithDOASAirLoop
eio diffs: VAV SYS 1 is a recirculation system (no outdoor air) so it should have a zero system central design heating load, and the diffs for reheat coil sizing look good, too.

- System Sizing Information, VAV SYS 1, Cooling, Sensible, 13220.08, 0.80120, 0.80120, CHICAGO_IL_USA ANNUAL COOLING 1% DESIGN CONDITIONS DB/MCWB, 7/21 00:00:00
- System Sizing Information, VAV SYS 1, Heating, Sensible, 9065.05, 0.49859, 0.49859, CHICAGO_IL_USA ANNUAL HEATING 99% DESIGN CONDITIONS DB, 1/21 01:00:00
- System Sizing Information, DOAS, Cooling, Sensible, 5685.65, 0.16562, 0.26412, CHICAGO_IL_USA ANNUAL COOLING 1% DESIGN CONDITIONS DB/MCWB, 7/21 00:00:00
- System Sizing Information, DOAS, Heating, Sensible, 9206.40, 0.13374, 0.26412, CHICAGO_IL_USA ANNUAL HEATING 99% DESIGN CONDITIONS DB, 1/21 24:00:00
+ System Sizing Information, VAV SYS 1, Cooling, Sensible, 11617.36, 0.80120, 0.80120, CHICAGO_IL_USA ANNUAL COOLING 1% DESIGN CONDITIONS DB/MCWB, 7/21 00:00:00
+ System Sizing Information, VAV SYS 1, Heating, Sensible, 0.00, 0.49859, 0.49859, ,  00:00:00
+ System Sizing Information, DOAS, Cooling, Sensible, 5636.75, 0.26412, 0.26412, CHICAGO_IL_USA ANNUAL COOLING 1% DESIGN CONDITIONS DB/MCWB, 7/21 00:00:00
+ System Sizing Information, DOAS, Heating, Sensible, 9206.40, 0.26412, 0.26412, CHICAGO_IL_USA ANNUAL HEATING 99% DESIGN CONDITIONS DB, 1/21 24:00:00
- Component Sizing Information, AirTerminal:SingleDuct:VAV:NoReheat, SPACE1-1 DOAS AIR TERMINAL, Design Size Constant Minimum Air Flow Fraction, 1.34439
+ Component Sizing Information, AirTerminal:SingleDuct:VAV:NoReheat, SPACE1-1 DOAS AIR TERMINAL, Design Size Constant Minimum Air Flow Fraction, 0.20000
- Component Sizing Information, AirTerminal:SingleDuct:VAV:Reheat, SPACE1-1 VAV REHEAT, Design Size Maximum Reheat Water Flow Rate [m3/s], 1.32891E-004
+ Component Sizing Information, AirTerminal:SingleDuct:VAV:Reheat, SPACE1-1 VAV REHEAT, Design Size Maximum Reheat Water Flow Rate [m3/s], 1.17091E-004
- Component Sizing Information, AirTerminal:SingleDuct:VAV:Reheat, SPACE1-1 VAV REHEAT, Design Size Reheat Coil Sizing Inlet Air Temperature [C], 12.20000
- Component Sizing Information, AirTerminal:SingleDuct:VAV:Reheat, SPACE1-1 VAV REHEAT, Design Size Reheat Coil Sizing Inlet Air Humidity Ratio [kgWater/kgDryAir], 3.00000E-003
- Component Sizing Information, Coil:Heating:Water, SPACE1-1 ZONE COIL, Design Size Rated Capacity [W], 6117.01392
- Component Sizing Information, Coil:Heating:Water, SPACE1-1 ZONE COIL, Design Size Maximum Water Flow Rate [m3/s], 1.32891E-004
- Component Sizing Information, Coil:Heating:Water, SPACE1-1 ZONE COIL, Design Size U-Factor Times Area Value [W/K], 141.32596
+ Component Sizing Information, AirTerminal:SingleDuct:VAV:Reheat, SPACE1-1 VAV REHEAT, Design Size Reheat Coil Sizing Inlet Air Temperature [C], 16.70000
+ Component Sizing Information, AirTerminal:SingleDuct:VAV:Reheat, SPACE1-1 VAV REHEAT, Design Size Reheat Coil Sizing Inlet Air Humidity Ratio [kgWater/kgDryAir], 8.00000E-003
+ Component Sizing Information, Coil:Heating:Water, SPACE1-1 ZONE COIL, Design Size Rated Capacity [W], 5389.72480
+ Component Sizing Information, Coil:Heating:Water, SPACE1-1 ZONE COIL, Design Size Maximum Water Flow Rate [m3/s], 1.17091E-004
+ Component Sizing Information, Coil:Heating:Water, SPACE1-1 ZONE COIL, Design Size U-Factor Times Area Value [W/K], 129.77653

5ZoneAirCooled_VRPSizing, 5ZoneAirCooled_VRPSizing_MaxZd
eio and table diffs for Zone-level OA flow rates per items 5 and 6 above.
5ZoneVAV-ChilledWaterStorage-Mixed_DCV_MaxZd and 5ZoneVAV-ChilledWaterStorage-Mixed_DCV_MultiPath
eio, eso, and table diffs
Zone MinOA is no longer adjusted by Std62 system-level ratios so this changes the powered induction unit minimum primary air flow rate, and also the reheat coil size.
Annual run of 5ZoneVAV-ChilledWaterStorage-Mixed_DCV_MultiPath shows some changes in annual energy use.
2% more heating gas, 2% decrease in cooling electricity (as related electric). Small change in hours not met (1 more heating not met out of 200, 5 more cooling out of 335).
Fault_FoulingEvapCooler_StripMallZoneEvapCooler, StripMallZoneEvapCoolerAutosized, StripMallZoneEvapCooler
table diffs - order of rows in Energy Meters table.
err diffs - Reported severe errors are the same, but they are now counted as 2 severe errors during sizing (because zone equipment is called sooner now in cases without system sizing, if there was autosized system equipment in this file, then the errors would be during sizing both before and after this PR).

   ** Severe  ** InitZoneEvaporativeCoolerUnit: ZoneHVAC:EvaporativeCoolerUnit = SMSTORE6 ZONE EVAP UNIT
   **   ~~~   ** ...unit fan volumetric flow rate less than evaporative cooler unit design supply air flow rate.
   . . .
   Before:
   ************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.
   ************* EnergyPlus Sizing Error Summary. During Sizing: 0 Warning; 0 Severe Errors.
   ************* EnergyPlus Completed Successfully-- 0 Warning; 2 Severe Errors; Elapsed Time=00hr 00min 28.24sec

   After:
   ************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.
   ************* EnergyPlus Sizing Error Summary. During Sizing: 0 Warning; 2 Severe Errors.
   ************* EnergyPlus Completed Successfully-- 0 Warning; 2 Severe Errors; Elapsed Time=00hr 00min 27.79sec

House-2FurnaceAC*
eio diffs - just small warmup convergence diffs
table diffs - Std62.1 reports - These files have two furnaces, one sized to 75% of the total load, and the other to 25%. Before this PR,, any zone-level flow rates in the Std 62 reports were the same for both systems which was wrong. Now they are different as expected. System level numbers were correct before and have not changed.
MultiStory and MicroCogeneration
rdd/mtd/table diffs - order of rows changed in Energy Meters table report. No change in values. Due to changes in ManageSizing to call zone equipment sooner when there is no system sizing.
RadLoTempElecTermReheat and RadLoTempHydrTermReheat
table diffs - In the new coil sizing details reports - before this PR, the Terminal Unit Reheat Coil Multiplier column was all -9999. Now there are values on the order of 2 or 3 - assuming they are correct.
RefBldgLargeHotelNew2004_Chicago
eio diffs - VAV min flow fraction is 1.0 now instead of 2+ - the whole reason this PR got started in the first place.

- Component Sizing Information, AirTerminal:SingleDuct:VAV:Reheat, CORRIDOR_FLR_3 VAV BOX COMPONENT, Design Size Constant Minimum Air Flow Fraction, 2.28980
+ Component Sizing Information, AirTerminal:SingleDuct:VAV:Reheat, CORRIDOR_FLR_3 VAV BOX COMPONENT, Design Size Constant Minimum Air Flow Fraction, 1.00000

HVACTemplate-5ZoneVRF and VariableRefrigerantFlow_5Zone
err diffs - some warnings now counted as sizing warnings due to earlier execution of VRF equipment.
VariableRefrigerantFlow_FluidTCtrl_HR_5Zone
err diffs - Small change reported ODB in warnings

 ** Warning ** AirConditioner:VariableRefrigerantFlow "VRF HEAT PUMP".
 **   ~~~   ** ...InitVRF: VRF Heat Pump Min/Max Outdoor Temperature in Heat Recovery Mode Limits have been exceeded and VRF heat recovery is disabled.
-   **   ~~~   ** ... Outdoor Dry-Bulb Temperature                       = 27.605
+   **   ~~~   ** ... Outdoor Dry-Bulb Temperature                       = 27.706
    **   ~~~   ** ... Heat Recovery Minimum Outdoor Dry-Bulb Temperature = -20.000
    **   ~~~   ** ... Heat Recovery Maximum Outdoor Dry-Bulb Temperature = 26.000
    **   ~~~   ** ... Check VRF Heat Pump Min/Max Outdoor Temperature in Heat Recovery Mode limits.
-   **   ~~~   **  During Warmup, Environment=MIAMI INTL AP ANN CLG .4% CONDNS DB=>MWB, at Simulation time=07/21 00:00 - 00:15
+   **   ~~~   **  During Sizing, Environment=MIAMI INTL AP ANN CLG .4% CONDNS DB=>MWB, at Simulation time=07/21 24:00 - 24:15

table diffs - In the new Coil Sizing Details table, significant differences in VRF terminal unit coil capacity and leaving conditions at "rating conditions".
???? Problem ???

DirectIndirectEvapCoolers, DirectIndirectEvapCoolersVSAS, HeatPumpWaterHeater, HeatPumpWaterHeaterStratified, RefBldgSecondarySchoolNew2004_Chicago, RefBldgSmallHotelNew2004_Chicago, and VSHeatPumpWaterHeater
eio diffs - change in time stamp for peak system heating load (no change in value)
LookupTables
eio diffs - just a change in order - table curve output shows before zone sizing output now.
table diffs - change in Design Size Constant Minimum Air Flow Fraction (no change in results, because there's a user-specified min frac)

Work Checklist

Add to this list or remove from it as applicable. This is a simple templated set of guidelines.

Title of PR should be user-synopsis style (clearly understandable in a standalone changelog context)
At least one of the following appropriate labels must be added to this PR to be consumed into the changelog:
- Defect: This pull request repairs a github defect issue. The github issue should be referenced in the PR description
- Refactoring: This pull request includes code changes that don't change the functionality of the program, just perform refactoring
- NewFeature: This pull request includes code to add a new feature to EnergyPlus
- Performance: This pull request includes code changes that are directed at improving the runtime performance of EnergyPlus
- DoNoPublish: This pull request includes changes that shouldn't be included in the changelog

Review Checklist

This will not be exhaustively relevant to every PR.

Code style (parentheses padding, variable names)
Functional code review (it has to work!)
If defect, results of running current develop vs this branch should exhibit the fix
CI status: all green or justified
Performance: CI Linux results include performance check -- verify this
Unit Test(s)
C++ checks:
- Argument types
- If any virtual classes, ensure virtual destructor included, other things

…inFlow6327

Myoldmopar

👍

Could you comment on the one question I had about the final calculation that pulls the flow back up to at least minOA?

Myoldmopar · 2017-09-22T02:37:01Z

src/EnergyPlus/SingleDuct.cc

@@ -2099,10 +2099,10 @@ namespace SingleDuct {
 		}
 		if ( Sys( SysNum ).ZoneMinAirFracMethod == ConstantMinFrac ) {
 			if ( ZoneSizingRunDone ) {
-				if ( CurZoneEqNum > 0 ) {
+				if ( CurTermUnitSizingNum > 0 ) {


Based on the issue description, I guess this gets the index correctly due to the extra TermUnitSizing objects being stored.

Myoldmopar · 2017-09-22T02:37:30Z

src/EnergyPlus/SingleDuct.cc

 					// use the combined defaults or other user inputs stored in DesCoolVolFlowMin
 					if ( Sys( SysNum ).MaxAirVolFlowRate > 0.0 ) {
-						MinAirFlowFracDes = FinalZoneSizing( CurZoneEqNum ).DesCoolVolFlowMin / Sys( SysNum ).MaxAirVolFlowRate;
+						MinAirFlowFracDes = min( 1.0, TermUnitFinalZoneSizing( CurTermUnitSizingNum ).DesCoolVolFlowMin / Sys( SysNum ).MaxAirVolFlowRate );


Makes sense to me.

Why would this ever be > 1 ? There is something else going on.

Valid point (why would this ever be > 1? One example is a hard-sized value for one and autosize for the other that aren't consistent. For the fully autosized case, other fixes in this PR should have gotten rid of that, but I haven't confirmed that.

Myoldmopar · 2017-09-22T02:39:10Z

src/EnergyPlus/SizingManager.cc

@@ -3768,6 +3768,9 @@ namespace SizingManager {
 					thisTUFZSizing.DesHeatOAFlowFrac = 0.0;
 				}
 				thisTUFZSizing.MinOA = thisFZSizing.MinOA * minOAFrac;
+
+				// Make sure cooling min flow is at least the minOA flow, regardless of the term unit cooling sizing ratio applied above
+				thisTUFZSizing.DesCoolVolFlowMin = max( thisTUFZSizing.DesCoolVolFlowMin, thisTUFZSizing.MinOA );


This seems like it stomps on things right at the end here. Is there any chance this could result in a DesCoolVolFlowMin too high and have the same problem (ratio>1.0) downstream somewhere?

Good question. I added this, because the DOAS system in 5ZoneAirCooledWithDOASAirLoop came back with a zero design min frac because it's airterminal sizing spec is 0 for cooling 1.0 for outdoor air.

One perspective is that the OA requirement should always be king at this point, so there should be two more lines here to make sure that DesHeatVolFlow and DesCoolVolFlow should be >=MinOA. But then what about all the other flavors of that? Will review the base zone sizing calcs to see which of these are checked against OA requirement in FinalZoneSizing.

The other perspective is that the equipment should sort this out and this line should go. The autosized airflow for this terminal unit was OK even without this line. It was just the autosized min frac that showed as zero.

@Myoldmopar @rraustad Back to sizing basics. The zone MinOA requirement impacts the cooling design flow rate during the base zone sizing calcs here. You can see from the blame that this has been the case since way-back-when. Interesting that this is only applied to cooling flow, and not heating, but that's how it is.

The way the air terminal sizing spec is working at the moment, the OA requirement will be the floor for the design cooling flow rate, even if a particular air terminal is supposed to deliver a fraction (or zero) of the OA. That's true with or without the line that was added here to adjust DesignCoolVolMinFlow.

I'm working on a fix for that now. I'm going to save some info about the impact of MinOA (like maybe DesignCoolVolFlowNoOA) that honors all the minima except MinOA and then use it here with the ratios to set TermUnitFinalZoneSizing.DesignCoolVolFlow appropriately. Not sure about all the other flavors of *Cool* here.

Myoldmopar · 2017-09-22T02:39:30Z

tst/EnergyPlus/unit/SingleDuct.unit.cc

+
+TEST_F( EnergyPlusFixture, VAVReheatTerminal_SizeMinFrac ) {
+	std::string const idf_objects = delimited_string( {
+		"Version,8.4;",


Version 8.4? 😃

What? It works. Will change if I change the other line.

Myoldmopar · 2017-09-22T02:40:20Z

tst/EnergyPlus/unit/SingleDuct.unit.cc

+	CurTermUnitSizingNum = 1;
+	DataSizing::TermUnitFinalZoneSizing( 1 ).DesCoolVolFlowMin = 0.5;
+	SingleDuct::SizeSys( SysNum );
+	EXPECT_EQ( 0.5, SingleDuct::Sys( SysNum ).ZoneMinAirFrac );


Makes sense.

Myoldmopar · 2017-09-22T02:40:34Z

tst/EnergyPlus/unit/SingleDuct.unit.cc

+	SingleDuct::Sys( SysNum ).ZoneMinAirFrac = AutoSize; // need to reset this so it sizes again
+	DataSizing::TermUnitFinalZoneSizing( 1 ).DesCoolVolFlowMin = 1.5;
+	SingleDuct::SizeSys( SysNum );
+	EXPECT_EQ( 1.0, SingleDuct::Sys( SysNum ).ZoneMinAirFrac );


Excellent. This unit test makes me feel very good about these changes.

…inFlow6327 Conflicts: tst/EnergyPlus/unit/SingleDuct.unit.cc

mjwitte · 2017-09-22T21:44:22Z

src/EnergyPlus/DataSizing.hh

@@ -455,6 +455,7 @@ namespace DataSizing {
 		bool EMSOverrideDesHeatMassOn; // true if EMS is acting on this structure
 		Real64 EMSValueDesHeatMassFlow; // Value EMS directing to use for Design Heating air mass flow [kg/s]
 		Real64 DesCoolMassFlow; // zone design cooling air mass flow rate [kg/s]
+		Real64 DesCoolMassFlowNoOA; // zone design cooling air mass flow rate with applying MinOA as a limit [kg/s]


Accidentally messed up this commit - it is a mix of new changes plus merging in develop. Initial display of this commit shows the new changes mostly, plus conflict resolution changes.

Myoldmopar · 2017-09-23T03:43:54Z

This seems good to go from my point of view. You're done with it right @mjwitte?

mjwitte · 2017-09-23T09:55:17Z

No, not quite done yet. I don't like the diffs in 5ZoneCoolBeam, so I'll revert those changes and sort that out later. Also, termunitsizing isn't flowing in correctly yet.

mjwitte · 2017-09-23T11:52:40Z

With this commit, airflow rates are where they should be. May still be an issue with system OA and reheat coil sizing. Will check back later.

…inFlow6327

rraustad · 2017-09-23T17:00:50Z

src/EnergyPlus/ZoneEquipmentManager.cc

+				}}
+
+				// Now make sure that the design cooling air flow rates are greater than or equal to the specified minimums including MinOA
+				{ Real64 MaxOfMinCoolVolFlow = 0.0; // max of the user specified design cooling minimum flows and min OA flow [m3/s]


What is the purpose of the open bracket here and close bracket at line 2773?

To limit the context of MaxOfMinCoolVolFlow and make sure it doesn't get confused with the other instance of MaxOfMinCoolVolFlow that was defined earlier without MinOA.

mjwitte · 2017-09-23T19:45:50Z

Made progress on the reheat coil sizing and the overall airloop sizing, but it's still not right if the system flow rate is specified in sizing:system along with airterminal sizing factors. Close.

Myoldmopar · 2017-09-24T12:17:09Z

src/EnergyPlus/DataSizing.cc

+		Real64 adjustedFlow = heatFlowNoOA * heatFlowRatio + ( heatFlowWithOA - heatFlowNoOA ) * this->SpecMinOAFrac;
+		return adjustedFlow;
+	}
+


These methods are so nice.

Yeah, but they are being added to DataSizing.cc what was a data-only file. I am not sure of the design policy but I would have expected such routines to be in SizingManager.cc. I guess the thinking is that since they are implemented as structure methods then this is the right place.

Myoldmopar · 2017-09-24T12:17:57Z

src/EnergyPlus/SimAirServingZones.cc

-					}
-					SysSizing( CurOverallSimDay, AirLoopNum ).NonCoinCoolMassFlow += ZoneSizing( CurOverallSimDay, CtrlZoneNum ).DesCoolMassFlow * coolFlowRatio / ( 1.0 + TermUnitSizing( TermUnitSizingIndex ).InducRat );
+					Real64 adjCoolMassFlow = TermUnitSizing( TermUnitSizingIndex ).applyTermUnitSizingCoolFlow( ZoneSizing( CurOverallSimDay, CtrlZoneNum ).DesCoolMassFlow, ZoneSizing( CurOverallSimDay, CtrlZoneNum ).DesCoolMassFlowNoOA );
+					SysSizing( CurOverallSimDay, AirLoopNum ).NonCoinCoolMassFlow += adjCoolMassFlow / ( 1.0 + TermUnitSizing( TermUnitSizingIndex ).InducRat );


mjwitte · 2017-09-24T18:36:42Z

The VRP diffs were not expected here. Investigating.

mjwitte · 2017-09-24T22:33:10Z

@Myoldmopar So, here's the status of this. In the original implementation of DesignSpecification:AirTerminal:Sizing (back in #6248) the limited set of test files I was using convinced me that the new sizing was working, and it does indeed flow through and, say if you specify a system to serve 50% of the cooling load, the flows and coils come out 50% smaller. Or, specifying one airloop to serve all of the heating/cooling (and no outdoor air) with a DOAS that serves all of the outdoor air and no heating/cooling - that works now.

But, I hadn't tested other more complicated combinations with air terminal sizing, like VRP, specified flow in the sizing:system object, sizing on "ventilationrequirement", etc. Those are what this PR is fixing. And it's turning out to be a lot of code changes - lots of places where FinalZoneSizing( CtrlZoneNum ) should be TermUnitFinalZoneSizing( TermUnitSizingIndex ) which include the air terminal sizing factors. Still working on this part.

So, the best path forward is probably to review #6272 and get that in. And if this one proves to be too much to throw in, then I'll add a caveat to the docs explaining what work and what doesn't at this point.

Myoldmopar · 2017-09-25T01:11:22Z

OK, I think given how far we are past the 11th hour, we should probably focus on your best path forward. Can you add those caveats to the documentation over in #6272 and I'll work on getting that in. Then we'll be done for 8.8.

…inFlow6327

mjwitte · 2018-03-12T20:52:05Z

@Myoldmopar @EnergyArchmage @rraustad OK, this is ready for review. Diffs are summarized/explained in the PR overview. Please look this over carefully - questions welcomed. I still need to look for any engineering ref changes that may be needed.

rraustad · 2018-03-12T23:51:26Z

src/EnergyPlus/SimAirServingZones.cc

 						ShowFatalError( "This is a defect. Please report this issue." );
 					}
 					if ( SysSizNum > 0 ) {
+						ZoneOAUnc = TermUnitFinalZoneSizing( TermUnitSizingIndex ).TotalOAFromPeople + TermUnitFinalZoneSizing( TermUnitSizingIndex ).TotalOAFromArea; // should not have diversity at this point


How are you splitting up people and area per terminal unit? line 4382 SimAirServingZones

rraustad · 2018-03-13T00:38:53Z

src/EnergyPlus/SizingManager.cc

+				// Outdoor air
+				thisTUFZSizing.MinOA = thisFZSizing.MinOA * minOAFrac;
+				thisTUFZSizing.TotalOAFromPeople = thisFZSizing.TotalOAFromPeople * minOAFrac;
+				thisTUFZSizing.TotalOAFromArea = thisFZSizing.TotalOAFromArea * minOAFrac;


Line 4355 SizingManager. So these are the total zone OA flow per person and zone, correct (from line 1640 of ZoneEquipmentManager)? And you move that data into each terminal unit sizing array which is then used for Std 62.1. Do you know the TU flow rate and the total zone flow rate here? You could use that ratio to allocate OA to each terminal unit. At the very least, you could divide by number of TU's per zone.

The user is supposed to manage OA allocation with DesignSpecification:AirTerminal:Sizing objects. I hadn't thought about trying to automatically allocate that. If the user puts more than one air terminal in the same zone without any DSATZ objects, then there will be excess OA. Flow rates are known here, so I suppose something could be done automatically for this case.

And just to clarify. TerminalUnitFinalZoneSizing is used for more than Std 62.1 calcs - it's used everywhere for terminal unit sizing, including .MinOA. So, then the question would be if we're going to automatically allocate OA for multiple terminal units without any DesignSpec AT Sizing objects, then do we automatically divide up the supply flow also? If there are no DSATZ objects, then the supply flow rate will be the same for every terminal unit in the same zone. So, that puts us back to dividing by the number of TUs per zone - but only if nobody in that zone has a DesignSpec AT Sizing object.

EnergyArchmage · 2018-03-14T19:14:26Z

src/EnergyPlus/SimAirServingZones.cc

 						//Vpz: "Primary" supply air from main air handler served by an oa mixer
-						ZonePA = FinalZoneSizing( CtrlZoneNum ).DesCoolVolFlow;
+						ZonePA = TermUnitFinalZoneSizing( TermUnitSizingIndex ).DesCoolVolFlow;
 						//Vdz: "Discharge" supply air delivered to zone by terminal unit
 						ZoneSA = max( TermUnitSizing( TermUnitSizingIndex ).AirVolFlow, ZonePA );


maybe this instance of TermUnitSizing should now be TermUnitFinalZoneSizing, line 4463 SimAirServingZones.cc

TermUnitSizing holds values that are set in the terminal units, e.g. here for PIU. The values should be based on TermUnitFinalZoneSizing with any scaling.

EnergyArchmage · 2018-03-14T19:17:36Z

src/EnergyPlus/SimAirServingZones.cc

 									// Don't allow the design terminal airflow to be less than the design heating airflow
-									TermUnitSizing( TermUnitSizingIndex ).AirVolFlow = max( TermUnitSizing( TermUnitSizingIndex ).AirVolFlow, FinalZoneSizing( CtrlZoneNum ).DesHeatVolFlow );
+									TermUnitSizing( TermUnitSizingIndex ).AirVolFlow = max( TermUnitSizing( TermUnitSizingIndex ).AirVolFlow, TermUnitFinalZoneSizing( TermUnitSizingIndex ).DesHeatVolFlow );


More TermUnitSizing vs TermUnitFinalZoneSizing here. And line 4607 below

EnergyArchmage · 2018-03-14T19:36:56Z

src/EnergyPlus/SimAirServingZones.cc

-			DataSizing::VpzMinClgByZone.dimension( NumOfZones, 0.0 );
-			DataSizing::VpzHtgByZone.dimension( NumOfZones, 0.0 );
-			DataSizing::VpzMinHtgByZone.dimension( NumOfZones, 0.0 );
+			DataSizing::VdzClgByZone.dimension( NumAirTerminalUnits, 0.0 );


Unfortunate that all these array variables are named *ByZone when now they should be *ByTerminal or something.

True, I could rename them if you think it's more clear.

EnergyArchmage · 2018-03-14T19:39:34Z

Pretty massive and important set of changes. I have reviewed the code changes and don't have any serious comments. Diffs seem appropriate

I/O Ref entry for DesignSpecification:AirTerminal:Sizing lists some limitations that I think have been addressed here, so the documentation can be revised to remove some caveats there.

EnergyArchmage · 2018-03-14T20:56:22Z

As for item # 10 in PR description, I have no idea. I am not up to speed with that VRF flavor. Presumably it is related to changes at line 7753 and 7767 in HVACVariableRefrigerantFlow.cc "Garate" stuff. seems like unrelated stuff crept in.

…inFlow6327

Myoldmopar · 2018-03-16T18:39:09Z

Looks good to me. I'm going to hold off on merging to let CI keep running on a few other branches, but this will go in within a couple hours.

VAV min flow frac and other sizing

af27546

mjwitte added the Defect Includes code to repair a defect in EnergyPlus label Sep 21, 2017

mjwitte added this to the EnergyPlus 8.8.0 milestone Sep 21, 2017

mjwitte added 2 commits September 21, 2017 15:34

VAV min flow frac sizing resolve diffs and failures

468595b

Merge remote-tracking branch 'remotes/origin/develop' into VAVDesignM…

01794c1

…inFlow6327

Myoldmopar approved these changes Sep 22, 2017

View reviewed changes

Merge remote-tracking branch 'remotes/origin/develop' into VAVDesignM…

a87c627

…inFlow6327 Conflicts: tst/EnergyPlus/unit/SingleDuct.unit.cc

mjwitte commented Sep 22, 2017

View reviewed changes

Myoldmopar mentioned this pull request Sep 23, 2017

Allow Multiple Air Loops to One Thermal Zone - Part 2 and Fix Zone Air Mass Balance #6272

Merged

20 tasks

Multiple Airloops - TermUnitFinalZoneSizing refinements

1e713e9

Merge remote-tracking branch 'remotes/origin/develop' into VAVDesignM…

d75ee25

…inFlow6327

rraustad reviewed Sep 23, 2017

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mjwitte added 2 commits September 23, 2017 23:27

Multiple Airloops - TermUnitFinalZoneSizing more refinements

1d32f46

Multiple Airloops - TermUnitFinalZoneSizing even more refinements

9d6c1ef

mjwitte changed the title ~~Fix VAV min flow frac > 1.0 and set some other sizing in singleduct to use TermUnitFinalZoneSizing~~ Fix VAV min flow frac > 1.0 and a bunch of termunitsizing issues related to multiple airloops Sep 24, 2017

Myoldmopar reviewed Sep 24, 2017

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Multiple Airloops - TermUnitFinalZoneSizing even more refinements II

2dce2f0

mjwitte modified the milestones: EnergyPlus 8.8.0, EnergyPlus Next Sep 25, 2017

mjwitte added 4 commits September 25, 2017 10:22

Merge remote-tracking branch 'remotes/origin/develop' into VAVDesignM…

b243eed

…inFlow6327

Air terminal sizing - Use TermUnitFinalZoneSizing in UpdateSysSizing

ad8586e

Tiny whitespace fix

7008d10

Merge remote-tracking branch 'remotes/origin/develop' into VAVDesignM…

e55796d

…inFlow6327

mjwitte added 2 commits March 7, 2018 20:50

Fix evap cooler unit tests

4929dae

Air terminal sizing - fix build warning

508ee56

mjwitte mentioned this pull request Mar 8, 2018

SolveRoot RegulaFalsi fails with an underflow in VRF model #6515

Closed

3 tasks

VRF sizing timing and protect against div by zero

36ed41b

mjwitte mentioned this pull request Mar 8, 2018

Underflow in CalcFluidHeatExchanger #6516

Closed

3 tasks

mjwitte added 2 commits March 8, 2018 16:50

Air terminal sizing - fix CoolBeam to use NonAirSysDesCoolLoad

97fdd40

Air terminal sizing - eliminate double scaling for air loops

85c8b33

NREL deleted a comment from nrel-bot-3 Mar 9, 2018

Air terminal sizing - fix ZoneSizing sequenced NoOA variables

102f82e

mjwitte requested review from Myoldmopar, rraustad and EnergyArchmage March 12, 2018 20:50

rraustad reviewed Mar 12, 2018

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rraustad reviewed Mar 13, 2018

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EnergyArchmage reviewed Mar 14, 2018

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EnergyArchmage approved these changes Mar 14, 2018

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mjwitte mentioned this pull request Mar 15, 2018

Suspect numbers in Airloop and Facility component loads reports #6337

Closed

3 tasks

mjwitte added 3 commits March 14, 2018 21:47

Merge remote-tracking branch 'remotes/origin/develop' into VAVDesignM…

94d3191

…inFlow6327

Air terminal sizing - delete list of limitations in I/O Ref

7f80804

Air terminal sizing - engineering ref

30ba4e2

Myoldmopar approved these changes Mar 16, 2018

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Myoldmopar merged commit 8074325 into develop Mar 17, 2018

Myoldmopar deleted the VAVDesignMinFlow6327 branch March 17, 2018 02:22

Myoldmopar mentioned this pull request Mar 17, 2018

VAV design minimum cooling air flow fraction > 1.0 when system adjusts zone flows #6327

Closed

5 tasks

Fix VAV min flow frac > 1.0 and a bunch of termunitsizing issues related to multiple airloops #6338

Fix VAV min flow frac > 1.0 and a bunch of termunitsizing issues related to multiple airloops #6338

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mjwitte commented Sep 21, 2017 • edited Loading

Pull request overview

Explanation of Diffs

Work Checklist

Review Checklist

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Myoldmopar commented Sep 23, 2017

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EnergyArchmage Mar 14, 2018 • edited Loading

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mjwitte commented Sep 24, 2017

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Myoldmopar commented Sep 25, 2017

mjwitte commented Mar 12, 2018

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EnergyArchmage Mar 14, 2018 • edited Loading

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EnergyArchmage commented Mar 14, 2018

EnergyArchmage commented Mar 14, 2018

Myoldmopar commented Mar 16, 2018

mjwitte commented Sep 21, 2017 •

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rraustad Mar 12, 2018 •

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