Add air terminal unit sizing option, allow air loops with no return path, and partially allow multiple air loops serving the same zone

[mjwitte]

Pull request overview

This new feature

1. Partially removes the limitation of one airloop (AirLoopHVAC) system per zone, allowing multiple air distribution units and multiple return air nodes in the same zone.
2. Adds an option to specify return air flow fraction (AirLoopHVAC field Design Return Air Flow Fraction of Supply Air Flow).
3. Adds options for user-control of sizing with DesignSpecification:AirTerminal:Sizing.
4. Allows an airloop with no return path.
5. Two new example files:
   5ZoneAirCooledWithDOASAirLoop (demostrates two air loops serving the same zones and DesignSpecification:AirTerminal:Sizing and no return path) and DOASDXCOIL_wADPBFMethod_NoReturnPath (demonstrates no return path, results identical to DOASDXCOIL_wADPBFMethod)
6. Not working yet Adds options to specify the return air node for heat gain from lights, airflow windows, and refrigeration cases.
7. Not working yet Manages allocation of return air flow to multiple airloops serving the same zone.

Note that there some limitations in the multiple air loop implementation related to room air models, output reporting, etc.

See #6272 for part 2 of this feature implementation.

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
• IDD changes:
  • Verify naming conventions and styles, memos and notes and defaults
  • Open windows IDF Editor with modified IDD to check for errors
  • If transition, add rules to spreadsheet
  • If transition, add transition source
  • If transition, update idfs
• If new idf included, locally check the err file and other outputs
• Documentation changes in place
• Changed docs build successfully
• ExpandObjects changes?
• If output changes, including tabular output structure, add to output rules file for interfaces

[rraustad]

Diff's from MacOS look OK. This is hopeful.

[rraustad]

@mjwitte can you take a quick look at this. I took the new example file DOASDXCOIL_wADPBFMethod_NoReturnPath and compared it to DOASDXCOIL_wADPBFMethod. The last several columns do not line up, but those shown below do line up and show diff's. Can you explain?

This is the last few columns in the spreadsheet that have diff's. Diff's are *NoReturn - original exam;ple file. I'll email the spreadsheet separately.

[rraustad]

Spreadsheet sent, please acknowledge.

[rraustad]

OK, now I'm a little confused. The coils operate the exact same way and the air flow rate is the same. Yet the heating coil outlet temp is different? There is no return in one case which means the system entering air temp is different. So this might be doing what it should be doing but I would think the coils would operate differently. @mjwitte might be able to explain.

Original:

AirLoopHVAC,
  DOAS,                    !- Name
  ,                        !- Controller List Name
  DOAS Availability Managers,  !- Availability Manager List Name
  autosize,                !- Design Supply Air Flow Rate {m3/s}
  DOAS Branches,           !- Branch List Name
  ,                        !- Connector List Name
  DOAS Air Loop Inlet,     !- Supply Side Inlet Node Name
  DOAS Return Air Outlet,  !- Demand Side Outlet Node Name
  DOAS Supply Path Inlet,  !- Demand Side Inlet Node Names
  DOAS Heating Coil Outlet;!- Supply Side Outlet Node Names

NoReturnPath:

AirLoopHVAC,
  DOAS,                    !- Name
  ,                        !- Controller List Name
  DOAS Availability Managers,  !- Availability Manager List Name
  autosize,                !- Design Supply Air Flow Rate {m3/s}
  DOAS Branches,           !- Branch List Name
  ,                        !- Connector List Name
  DOAS Outdoor Air Inlet,  !- Supply Side Inlet Node Name
  ,                        !- Demand Side Outlet Node Name
  DOAS Supply Path Inlet,  !- Demand Side Inlet Node Names
  DOAS Heating Coil Outlet;!- Supply Side Outlet Node Names

[rraustad]

And the coils are fighting each other, but that is the same as the original file. This may be due to humidity control but if there is no return in one case then shouldn't the coil operation change?

SetpointManager:MultiZone:Humidity:Maximum,
  Maximum MZone HumRatio setpoint,  !- Name
  DOAS,                    !- HVAC Air Loop Name
  0.003,                   !- Minimum Setpoint Humidity Ratio {kgWater/kgDryAir}
  0.015,                   !- Maximum Setpoint Humidity Ratio {kgWater/kgDryAir}
  DOAS Dehumidifier Setpoint Nodes;  !- Setpoint Node or NodeList Name

NodeList,
  DOAS Dehumidifier Setpoint Nodes,  !- Name
  DOAS Cooling Coil Outlet;!- Node 1 Name

[rraustad]

It appears in the figures above that when there is air flow, the results are identical. That's good, but I still can't figure out why since the inlet air temp is different, right?

[mjwitte]

This should be 100% OA so the return air gets relieved and has no impact.

…

-------- Original message -------- From: Richard Raustad <[email protected]> Date: 8/19/17 2:15 PM (GMT-06:00) To: NREL/EnergyPlus <[email protected]> Cc: "Michael J. Witte" <[email protected]>, Mention <[email protected]> Subject: Re: [NREL/EnergyPlus] Add air terminal unit sizing option, allow air &nbsp; loops with no return path, and partially allow multiple air loops serving the &nbsp; same zone (#6248) It appears in the figures above that when there is air flow, the results are identical. That's good, but I still can't figure out why since the inlet air temp is different, right? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread. {"api_version":"1.0","publisher":{"api_key":"05dde50f1d1a384dd78767c55493e4bb","name":"GitHub"},"entity":{"external_key":"github/NREL/EnergyPlus","title":"NREL/EnergyPlus","subtitle":"GitHub repository","main_image_url":"https://cloud.githubusercontent.com/assets/143418/17495839/a5054eac-5d88-11e6-95fc-7290892c7bb5.png","avatar_image_url":"https://cloud.githubusercontent.com/assets/143418/15842166/7c72db34-2c0b-11e6-9aed-b52498112777.png","action":{"name":"Open in GitHub","url":"https://github.com/NREL/EnergyPlus"}},"updates":{"snippets":[{"icon":"PERSON","message":"@rraustad in #6248: It appears in the figures above that when there is air flow, the results are identical. That's good, but I still can't figure out why since the inlet air temp is different, right?"}],"action":{"name":"View Pull Request","url":"#6248 (comment)"}}}

[rraustad]

That's obvious. Why doesn't the coil operation change?

[mjwitte]

The node name has changed but the conditions at the first coil inlet should be identical. In both cases it should be OA conditions plus maybe fan heat ( I forget where the fan is).

…

-------- Original message -------- From: Richard Raustad <[email protected]> Date: 8/19/17 3:33 PM (GMT-06:00) To: NREL/EnergyPlus <[email protected]> Cc: "Michael J. Witte" <[email protected]>, Mention <[email protected]> Subject: Re: [NREL/EnergyPlus] Add air terminal unit sizing option, allow air &nbsp; loops with no return path, and partially allow multiple air loops serving the &nbsp; same zone (#6248) That's obvious. Why doesn't the coil operation change? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread. {"api_version":"1.0","publisher":{"api_key":"05dde50f1d1a384dd78767c55493e4bb","name":"GitHub"},"entity":{"external_key":"github/NREL/EnergyPlus","title":"NREL/EnergyPlus","subtitle":"GitHub repository","main_image_url":"https://cloud.githubusercontent.com/assets/143418/17495839/a5054eac-5d88-11e6-95fc-7290892c7bb5.png","avatar_image_url":"https://cloud.githubusercontent.com/assets/143418/15842166/7c72db34-2c0b-11e6-9aed-b52498112777.png","action":{"name":"Open in GitHub","url":"https://github.com/NREL/EnergyPlus"}},"updates":{"snippets":[{"icon":"PERSON","message":"@rraustad in #6248: That's obvious. Why doesn't the coil operation change?"}],"action":{"name":"View Pull Request","url":"#6248 (comment)"}}}

[rraustad]

Note in this figure, the system inlet node temp is identical when air flow > 0. So OK, the same inlet temp exists and coil performance is the same. It's a blow thru fan and this temp is before the fan.

[rraustad]

So the heating coil outlet temp is not different when air flow > 0. Since there is no OA mixer, the system inlet temp = OAT now when air flow = 0. Consider this reviewed and accepted.

[rraustad]

This is a little weird. The compiler says this is unused:

line 543 DataZoneEquipment.
ZoneEquipList( ControlledZoneNum ).EquipIndex = 0;

This is a glitch not a show stopper.

[rraustad]

No, it's the header file, saying ZoneEquipConfig isn't used.

extern Array1D< EquipConfiguration > ZoneEquipConfig;

[rraustad]

I agree. Put this in place for future revisions.

[rraustad]

Reviewed and merged.

[rraustad]

I don't know what issue this relates to nor the Pivotal ticket.