Extend Spaces to Sizing and HVAC #9982

mjwitte · 2023-04-26T20:03:46Z

Pull request overview

Partially address Extend Spaces to Sizing #8927
- When ZoneAirHeatBalanceAlgorithm "Do Space Heat Balance for Sizing" = Yes, zone sizing is also done for all spaces. The HVAC Sizing Summary table report will include subtables for Space Sensible Cooling and Heating as well as for Zone Sensible Cooling and Heating. Space Sizing will also be reported to the eio output.
- At this stage, the space sizing results are reported, but not used.
- Zone sizing remains unchanged, sizing for all spaces in the zone lumped together which is essentially the same as the coincident space load.
Partially addresses Extend Spaces to HVAC #8928
- Adds two new objects SpaceHVAC:EquipmentConnections and SpaceHVAC:ZoneEquipmentSplitter.
- These objects allow one or more zones to be simulated at the space level for HVAC, leading to independent air temperature and humidity in each space.
TODO in this pull request:
- Review zone vs space calcs carefully.
- Finalize IDD
TODO in future pull requests for v23.2:
- Add unit tests.
- Add engineering ref notes.
- Use the space exhaust and return nodes?
- Set zone temperature and humidity based on lumping spaces together.
- Change surface heat balance to use space air conditions instead of zone.
- For zones without space heat balance set all space conditions to the zone condition.
- Use space return node fields
- Add checks and warnings for various constraints (e.g. if one space has SpaceHVAC then all spaces in that zone must also).
TODO in future pull requests post-v23.2:
- Allow zone equipment sizing to be based on coincident or non-coincident space loads. - IDD change

Pull Request Author

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

Reviewer

This will not be exhaustively relevant to every PR.

rraustad · 2023-04-26T20:36:12Z

design/FY2023/NFP-Space Sizing and HVAC.md

+```
+
+### ZoneHVAC:SpaceSplitter
+* *New object, splits the air flow from a single piece of zone equipment to one or more Spaces.*


How does the air loop splitter know how much air goes to each zone without these fraction inputs? The zone air flows create these fractions among a group of zones (i.e., it's not the splitter that does this). And if there is a splitter doesn't there need to be a mixer? My point is that I think you can use the existing splitter/mixer objects just like the air loop. The only question I have is the mechanism to get the zone (space) flow rates back to the outlet nodes of the splitter (space splitter). The answer is buried in the node maxavail data.

Good questions. A diagram would be helpful. Currently, let's say we have a 2-zone airloop.

AirloopOutlet --> ZoneSplitter --> Zone1 ATU Inlet --> Zone1 ATU Outlet --> Zone 1 |--> Zone2 ATU Inlet --> Zone2 ATU Outlet --> Zone 2

The ATUs control the flow and set maxavail on the ATU Inlet nodes which gets passed back up to the airloop.
The proposed method keeps all of the same nodes as above but adds the SpaceSplitter between the ATU outlet and the Space inlet nodes.

AirloopOutlet --> ZoneSplitter --> Zone1 ATU Inlet --> Zone1 ATU Outlet --> SpaceSplitter1--> Space 1a Supply Inlet --> Space 1a (Zone 1) | |--> Space 1b Supply Inlet --> Space 1b (Zone 1) |--> Zone2 ATU Inlet --> Zone2 ATU Outlet --> SpaceSplitter2--> Space 2a Supply Inlet (Zone 2)

So, the flow controls for the main airloop would stay the same, and the SpaceSplitter would divide up the flow to the various space diffuser outlets (which are completely passive with no controls on them). If the thermostat is located in a specific space, then the ATU will control total flow to give the controlling space the flow it needs (kind of the way unitary uses the control zone flow fraction to pro-rate the output). I'm sure there are some holes in the scheme yet.

In the first diagram, Zone1 and Zone 2 have design flow rates. The air loop, and the splitter, do not know those flow rates, yet the correct amount of air gets to each zone. In the second diagram, Space 1a, Space 1b, and Space 2a all have design flow rates. I don't see what's changed to need a new object. The existing splitter divides up flows without the need for flow fraction inputs. The only difference here is a ganged splitter configuration but flow is still determined from the design flow rates. Maybe in the Splitter code, space splitters are modeled first so that the zone splitters know the same information known now at the zone splitter outlet nodes. I agree you could do this either way with the same result. I think all you would need to do is place the space MassFlowRateMax and MaxAvail on the space inlet node and the existing splitter object works the same way it does now. Then model space splitters first to pass the information up to the zone splitters. Easier said than done?

As proposed, there is no object or field to specify space design flow rates (or user specified flow rates/fractions) for the space inlets, except the SpaceSplitter. If we put a ZoneSplitter there, where would the space-level flow information reside?

The proposed "Do Space Heat Balance for Sizing" tentatively means that given a space load you would pass a supply air T and w (from Sizing:Zone) to the space and calculate the space air flow rate. A Tstat is needed in the space for this method or the single Tstat within the zone could be used, to get the space SPs. I'm not sure if this proposal intends to do that or not but if it does you have the space air flows and therefore the space fractions. If the space air flows are not calculated and the space loads are calculated, the space loads provide the space fractions. This seems tricky for non-coincident sizing since the space peak times may not line up with the zone peak time, and then what would happen? I think here non-coincident applies to zones, not spaces.

I assume the intent is to split the zone air flow into space flows at fixed fractions, and those flows sum to meet the coincident space peak load and air flow that match the zone. If a sizing run is done then you have the information needed to calculate the fractions. If the intent is to allow the user to "test and balance" the space diffusers (likely before they know the zone/space loads) then you would need an input. So it seems you only need these fractions when sizing is not performed. How about the AirLoopHVAC:ZoneSplitter? A single input for a space name/fraction pair list is required if the inlet node connects to a splitter and all outlet nodes connect to space inlet nodes. After doing this I'm not sure this is any better. The last 2 objects are really no better than your original suggestion except that when autosizing the FlowFractionList isn't needed. I'm also not sure what a 3rd party front end would want, use of the same object, or a specific object per use case. Proceed at will. Another thought, for non-autosized, you know the space loads prior to simulating the air systems and there is also an opportunity to calculate the space fractions. But then the space fractions would vary and that would be wierd (but all set points would be met!). Consider this discussion food for thought.

AirLoopHVAC:ZoneSplitter, Zone Supply Air Splitter 1, !- Name , !- Space Name and Flow Fraction List Zone Eq In Node, !- Inlet Node Name SPACE1-1 Space Splitter, !- Outlet 1 Node Name SPACE2-1 ATU In Node, !- Outlet 2 Node Name SPACE3-1 ATU In Node, !- Outlet 3 Node Name SPACE4-1 ATU In Node, !- Outlet 4 Node Name SPACE5-1 ATU In Node; !- Outlet 5 Node Name AirLoopHVAC:ZoneSplitter, Zone Space1-1 Air Splitter, !- Name SPACE1-1 Flow Fraction List, !- Space Name and Flow Fraction List SPACE1-1 Space Splitter, !- Inlet Node Name SPACE1-1a ATU In Node, !- Outlet 1 Node Name SPACE1-1b ATU In Node; !- Outlet 2 Node Name ZoneHVAC:FlowFractionList, SPACE1-1 Flow Fraction List, !- Name 0.4, !- Space Fraction for Outlet 1 Node 0.6; !- Space Fraction for Outlet 2 Node

I just looked at the Space object and a flow fraction input would work there as well.

I assume the intent is to split the zone air flow into space flows at fixed fractions, and those flows sum to meet the coincident space peak load and air flow that match the zone. If a sizing run is done then you have the information needed to calculate the fractions.

Yes, if autosized.

. If the intent is to allow the user to "test and balance" the space diffusers (likely before they know the zone/space loads) then you would need an input.

Either way, we need an autosizable input somewhere. Same as VAV terminal unit supply flow rate.

rraustad · 2023-04-27T16:18:18Z

design/FY2023/NFP-Space Sizing and HVAC.md

+       \type node
+  A3 ; \field Space Air Inlet Node or NodeList Name
+       \type node
+```


Or even here is better to add the flow fraction? I assume unconditioned spaces are not allowed in a conditioned zone so each space would have this object.

Or even here is better to add the flow fraction? I assume unconditioned spaces are not allowed in a conditioned zone so each space would have this object.

Maybe, but this would not allow different balancing for different equipment. I'll work on expanding the NFP and adding some diagrams to consider some options here.

Also, I started with a space equipment list to allow space-level HVAC equipment, then decide that wasn't necessary, but I probably need to allow that back in, because a fan coil, say, would rarely serve more than one room (space).

As a side note, I always find the reverse maxavail flow resolution in the airloops to be rather opaque (i.e. I can't follow it in the code). So my goal is to keep this as simple and straightforward as possible.

nrel-bot-2c · 2023-05-04T15:05:04Z

@mjwitte it has been 7 days since this pull request was last updated.

…gHVAC

rraustad · 2023-05-05T21:17:40Z

design/FY2023/NFP-Space Sizing and HVAC.md

+       \units dimensionless
+       \minimum 0.0
+       \maximum 1.0
+       \autosizable


Should probably run these extensible fields out to about 10 in the idd when implemented. I can see a hallway with 5 or more spaces on a single zone on each side of the hallway.

rraustad · 2023-05-05T21:35:25Z

design/FY2023/NFP-Space Sizing and HVAC.md

+       \required-field
+       \type node
+  A3 ; \field Space Air Inlet Node or NodeList Name
+       \type node


I did not understand this on the first go around. Why doesn't a space have an exhaust or return outlet node? Will these nodes be implied as connecting to a zone exhaust/return outlet? and how to know which space has which outlet type? If an air loop connects to these spaces then yes, the air flow would sum to a zone return node. If a PTAC is connected to a space then the space would need an exhaust node. Also need a space exhaust node for "space" exhaust fans.

Yeah, I was hoping to avoid space-level return/exhaust nodes, but that might not work out.

EnergyArchmage · 2023-05-17T18:48:59Z

design/FY2023/NFP-Space Sizing and HVAC.md

+Zone,Sum,Zone Heating Setpoint Not Met While Occupied Time [hr]
+Zone,Sum,Zone Cooling Setpoint Not Met Time [hr]
+Zone,Sum,Zone Cooling Setpoint Not Met While Occupied Time [hr]
+```


These Setpoint Not Met Time output variables seem important. Seems like a clear method for how the space level results get rolled up to the zone level will be needed, eg. average temperature for zone first and then compare to setpoint, or is zone unmet if any spaces are unmet.

…gHVAC

nrel-bot · 2023-07-14T00:13:42Z

@mjwitte @Myoldmopar it has been 28 days since this pull request was last updated.

…gHVAC

mjwitte

Code walkthru part 1

mjwitte · 2023-08-17T22:14:50Z

src/EnergyPlus/DataHeatBalance.hh

@@ -453,6 +453,9 @@ namespace DataHeatBalance {
        Real64 ExtGrossWallArea = 0.0;                  // Exterior Wall Area for Zone (Gross)
        Real64 ExteriorTotalSurfArea = 0.0;             // Total surface area of all exterior surfaces for Zone
        int SystemZoneNodeNumber = 0;                   // This is the zone or space node number for the system for a controlled zone
+        Real64 FloorArea = 0.0;                         // Floor area used for this space


Move these to be available for both zone and space under the same field names. Changes space floorArea to ZoneSpace FloorArea which cause a bunch of case changes anywhere space floorArea was used. Same for totOccupants to TotOccupants.

I know it's really difficult to predict refactors like this, but it could help to take a quick look through the code you want to touch in your next phase, and quickly do some renaming in a first-pass PR before functional changes. I get that it won't be obvious at first, just saying that would make explaining and digesting the PR changes easier all around.

mjwitte · 2023-08-17T22:16:06Z

src/EnergyPlus/DataSizing.cc

@@ -314,6 +314,100 @@ void ZoneSizingData::allocateMemberArrays(int const numOfTimeStepInDay)
    this->LatentHeatFlowSeq.dimension(numOfTimeStepInDay, 0.0);
 }

+void TermUnitZoneSizingData::allocateMemberArrays(int const numOfTimeStepInDay)


Some new methods for the new struct TermUnitZoneSizingData which is a subset of ZoneSizingData.

mjwitte · 2023-08-17T22:18:27Z

src/EnergyPlus/DataSizing.hh

@@ -594,15 +594,104 @@ namespace DataSizing {
        ZoneSizing zoneSizingMethod = ZoneSizing::Invalid; // load to sizing on: sensible, latent, sensibleandlatent, sensibleonlynolatent
        std::string CoolSizingType;                        // string reported to eio, Cooling or Latent Cooling
        std::string HeatSizingType;                        // string reported to eio, Heating or Latent Heating
+        std::string CoolPeakDateHrMin;                     // date:hr:min of cooling peak


These were loose arrays, moved them into the ZoneSizingData struct.

mjwitte · 2023-08-17T22:18:56Z

src/EnergyPlus/DataSizing.hh

        void zeroMemberData();
        void allocateMemberArrays(int numOfTimeStepInDay);
    };

+    // based on ZoneSizingData but only member variables that are actually used by terminal unit sizing
+    struct TermUnitZoneSizingData


New struct, subset of ZoneSizingData.

So does ZoneSizingData inherit this subset class now so that these variables aren't repeated?

mjwitte · 2023-08-17T22:20:50Z

src/EnergyPlus/DataSizing.hh

+    Array2D<DataSizing::ZoneSizingData> SpaceSizing;                      // Data for space sizing (all data, all design)
+    EPVector<DataSizing::ZoneSizingData> FinalSpaceSizing;                // Final data for space sizing including effects
+    Array2D<DataSizing::ZoneSizingData> CalcSpaceSizing;                  // Data for space sizing (all data)
+    EPVector<DataSizing::ZoneSizingData> CalcFinalSpaceSizing;            // Final data for space sizing (calculated only)


New space sizing arrays.

mjwitte · 2023-08-17T22:28:25Z

src/EnergyPlus/HVACCooledBeam.cc

-                                           state.dataSize->ZoneSizThermSetPtHi(state.dataSize->CurZoneEqNum));
+                                           state.dataSize->TermUnitFinalZoneSizing(state.dataSize->CurTermUnitSizingNum).ZoneSizThermSetPtHi);


Moving some of the loose arrays into the TermUnitFinalZoneSizing struct caused a bunch of changes like this all over the HVAC code.

mjwitte · 2023-08-17T22:29:32Z

src/EnergyPlus/HeatBalanceAirManager.cc

-    if (state.dataHeatBal->doSpaceHeatBalanceSizing || state.dataHeatBal->doSpaceHeatBalanceSimulation) {
-        state.dataHeatBal->spaceAirRpt.allocate(state.dataGlobal->NumOfZones);
+    if (state.dataHeatBal->doSpaceHeatBalanceSimulation) {
+        state.dataHeatBal->spaceAirRpt.allocate(state.dataGlobal->numSpaces);


Some related cleanup of existing code.

mjwitte · 2023-08-17T22:30:04Z

src/EnergyPlus/OutputReportPredefined.cc

@@ -438,6 +438,26 @@ namespace OutputReportPredefined {

        s->pdrSizing = newPreDefReport(state, "HVACSizingSummary", "Size", "HVAC Sizing Summary");

+        s->pdstSpaceClSize = newPreDefSubTable(state, s->pdrSizing, "Space Sensible Cooling");


New space sizing output tables.

mjwitte · 2023-08-17T22:35:41Z

src/EnergyPlus/SizingManager.cc

@@ -592,180 +583,36 @@ void ManageSizing(EnergyPlusData &state)

    // report sizing results to eio file
    if (state.dataSize->ZoneSizingRunDone) {
+        bool isSpace = true;
+        if (state.dataHeatBal->doSpaceHeatBalanceSizing) {
+            for (int spaceNum = 1; spaceNum <= state.dataGlobal->numSpaces; ++spaceNum) {


Report space sizing, then zone sizing, to both eio and table.

mjwitte · 2023-08-17T22:36:56Z

src/EnergyPlus/SizingManager.cc

        for (int CtrlZoneNum = 1; CtrlZoneNum <= state.dataGlobal->NumOfZones; ++CtrlZoneNum) {
            if (!state.dataZoneEquip->ZoneEquipConfig(CtrlZoneNum).IsControlled) continue;
-            if (state.dataSize->FinalZoneSizing(CtrlZoneNum).DesCoolVolFlow > 0.0) {


Moved a bunch to shared reportZoneSizing function.

mjwitte

Code walkthru part 2 of 2.

mjwitte · 2023-08-17T22:42:03Z

src/EnergyPlus/ZoneEquipmentManager.cc

@@ -380,6 +380,305 @@ void InitZoneEquipment(EnergyPlusData &state, bool const FirstHVACIteration) //
        airLoopFlow.ExcessZoneExhFlow = 0.0;
    }
 }
+void sizeZoneSpaceEquipmentPart1(EnergyPlusData &state,


Split SizeZoneEquipment into pieces that can be re-used for zones and spaces.

mjwitte · 2023-08-17T22:46:50Z

src/EnergyPlus/ZoneEquipmentManager.cc

+        if (state.dataHeatBal->doSpaceHeatBalanceSimulation && !state.dataGlobal->DoingSizing) {
+            for (int spaceNum : state.dataHeatBal->Zone(ControlledZoneNum).spaceIndexes) {


Zero some things at the space level prior to simulating zone equipment.

mjwitte · 2023-08-17T22:47:34Z

src/EnergyPlus/ZoneEquipmentManager.cc

@@ -3461,17 +3624,47 @@ void SimZoneEquipment(EnergyPlusData &state, bool const FirstHVACIteration, bool
                }
            }

-            UpdateSystemOutputRequired(state, ControlledZoneNum, SysOutputProvided, LatOutputProvided, EquipTypeNum);
+            // If SpaceHVAC is active and this equipment has a space splitter, distribute the equipment output and update the spaces


Apply the SpaceHVAC:ZoneEquipmentSplitter for this piece of zone equip.

mjwitte · 2023-08-17T22:48:59Z

src/EnergyPlus/ZoneEquipmentManager.cc

-                    TotInletAirMassFlowRateMaxAvail += thisNode.MassFlowRateMaxAvail;
-                    TotInletAirMassFlowRateMin += thisNode.MassFlowRateMin;
-                    TotInletAirMassFlowRateMinAvail += thisNode.MassFlowRateMinAvail;
+            // SpaceHVAC TODO: For now, ZoneMassBalance happens at the zone level, not space


mjwitte · 2023-08-17T22:49:24Z

src/EnergyPlus/ZoneEquipmentManager.cc

@@ -4365,12 +4560,6 @@ void CalcZoneMassBalance(EnergyPlusData &state, bool const FirstHVACIteration)
                CalcZoneMixingFlowRateOfReceivingZone(state, ZoneNum, ZoneMixingAirMassFlowRate);
                ZoneMixingNetAirMassFlowRate = massConservation.MixingMassFlowRate - massConservation.MixingSourceMassFlowRate;
            }
-            auto &zoneNode = Node(zoneEquipConfig.ZoneNode);


Moved to shared function.

mjwitte · 2023-08-17T22:50:02Z

src/EnergyPlus/ZoneTempPredictorCorrector.cc

-            if (state.dataHeatBal->doSpaceHeatBalanceSizing || state.dataHeatBal->doSpaceHeatBalanceSimulation) {
+            if (state.dataHeatBal->doSpaceHeatBalanceSimulation) {


Some more related cleanup of existing code.

Myoldmopar · 2023-08-18T16:22:10Z

@mjwitte nice job getting clean CI! EIO diffs in the two space example files appear to be the only meaningful changes, which I would expect to see.

Thanks for the code walk-through, that's super helpful! I'll take a look now.

Myoldmopar · 2023-08-18T16:23:40Z

Partially address Extend Spaces to Sizing #8927

When ZoneAirHeatBalanceAlgorithm "Do Space Heat Balance for Sizing" = Yes, zone sizing is also done for all spaces. The HVAC Sizing Summary table report will include subtables for Space Sensible Cooling and Heating as well as for Zone Sensible Cooling and Heating. Space Sizing will also be reported to the eio output.

At this stage, the space sizing results are reported, but not used.

Zone sizing remains unchanged, sizing for all spaces in the zone lumped together which is essentially the same as the coincident space load.

Partially addresses Extend Spaces to HVAC #8928

OK, this makes sense, and is a big reason why we are getting clean CI.

Adds two new objects SpaceHVAC:EquipmentConnections and SpaceHVAC:ZoneEquipmentSplitter.

These objects allow one or more zones to be simulated at the space level for HVAC, leading to independent air temperature and humidity in each space.

Nice.

Myoldmopar

Well. This is big 😆

You've obviously done a ton of work here, and nothing raises a red flag. It's tough to scrutinize any one specific change because so many of the changes had to be spread around. I'm encouraged that CI is happy -- you didn't break anything in the current code. As @rraustad would say, we shouldn't hold this up arbitrarily and we probably need to get this out and available to users and refine it over time.

Myoldmopar · 2023-08-18T16:28:30Z

src/EnergyPlus/DataHeatBalance.hh

@@ -453,6 +453,9 @@ namespace DataHeatBalance {
        Real64 ExtGrossWallArea = 0.0;                  // Exterior Wall Area for Zone (Gross)
        Real64 ExteriorTotalSurfArea = 0.0;             // Total surface area of all exterior surfaces for Zone
        int SystemZoneNodeNumber = 0;                   // This is the zone or space node number for the system for a controlled zone
+        Real64 FloorArea = 0.0;                         // Floor area used for this space


I know it's really difficult to predict refactors like this, but it could help to take a quick look through the code you want to touch in your next phase, and quickly do some renaming in a first-pass PR before functional changes. I get that it won't be obvious at first, just saying that would make explaining and digesting the PR changes easier all around.

Myoldmopar · 2023-08-18T16:30:05Z

src/EnergyPlus/DataSizing.hh

        void zeroMemberData();
        void allocateMemberArrays(int numOfTimeStepInDay);
    };

+    // based on ZoneSizingData but only member variables that are actually used by terminal unit sizing
+    struct TermUnitZoneSizingData


So does ZoneSizingData inherit this subset class now so that these variables aren't repeated?

Myoldmopar · 2023-08-18T16:30:31Z

src/EnergyPlus/DataZoneEquipment.hh

+        int zoneEquipInletNodeNum = 0;
+        DataZoneEquipment::SpaceEquipSizingBasis spaceSizingBasis = DataZoneEquipment::SpaceEquipSizingBasis::Invalid;
+        std::vector<ZoneEquipSplitterMixerSpace> spaces;
+    };


Nice clean little structs 👍 👍

Myoldmopar · 2023-08-18T16:31:24Z

src/EnergyPlus/OutputReportPredefined.hh

-        this->columnTag.deallocate();
-        this->tableEntry.deallocate();
-        this->CompSizeTableEntry.deallocate();
-        this->ShadowRelate.deallocate();


Oh my gawd. 👍

rraustad

Review of IO Ref and IDD.

rraustad · 2023-08-18T16:30:36Z

doc/input-output-reference/src/overview/group-zone-equipment.tex

+\subsection{SpaceHVAC:EquipmentConnections}\label{spacehvacequipmentconnections}
+
+If HVAC equipment is modeled at the Space level for one or more zones, the SpaceHVAC:EquipmentConnections statement defines the node connections to a space. Any space modeled with SpaceHVAC:EquipmentConnections will have its own air temperature and humidity ratio, and surfaces and internal gains in the zone will interact with the space conditions.
+Note that all nodes mentioned in the SpaceHVAC:EquipmentConnections input must be unique. That is, all nodes in all the SpaceHVAC:EquipmentConnections statements referenced by the ``Space Air Inlet Nodes'', ``Space Air Exhaust Nodes'', ``Space Air Node Name'' and ``Space Return Air Node Name'' cannot have any node name appearing more than once. Unlike ZoneHVAC:EquipmentConnections, there is no equipment list. Equipment is connected to spaces using \hyperref[spacehvaczoneequipmentsplitter]{SpaceHVAC:ZoneEquipmentSplitter}. If any space in a zone has a SpaceHVAC:EquipmentConnections object, then all spaces in that zone must have one, even if they are not served by any HVAC equipment. SpaceHVAC is only used when \hyperref[zoneairheatbalancealgorithm]{ZoneAirHeatBalanceAlgorithm} ``Do Space Heat Balance for Simulation'' is Yes. 


I checked that the minimum fraction was indeed 0. But it can also be autosized. I guess if the user selects autosize then this space IS actually served by the HVAC equipment. There is no way to know if this space is served by the HVAC system other than a hard 0 as the fraction. Not requesting changes, just stating an observation.

N1, \field Space 1 Fraction \note Fraction of this zone equipment output or airflow distributed to this space. \default autosize \units dimensionless \minimum 0.0

rraustad · 2023-08-18T17:09:04Z

doc/input-output-reference/src/overview/group-zone-equipment.tex

+
+\paragraph{Field: Space Return Air Node 1 Flow Rate Fraction Schedule Name}\label{field-space-return-air-flow-rate-fraction-schedule-name}
+
+The name of a schedule to specify the return air flow rate for the first return air node as a fraction of the base return air. If the next field is blank, then the return air flow rate is the total supply inlet flow rate to the space less the total exhaust node flow rate from the space multiplied by this schedule name. If this field is left blank, the schedule defaults to 1.0 at all times.


So if this schedule fraction is 0.5, assuming no exhaust, then the return flow is 1/2 of the space total supply inlet flow (the sum of all the space inlets). Where does the rest of the air go? I have to applaud the space concept effort here but boy is it hard to grasp all the connections/interactions.

This is the same as the existing Zone equip connection object. If there's a second airloop serving the zone or space excess air will go there otherwise it's exfiltration

rraustad · 2023-08-18T17:16:51Z

doc/input-output-reference/src/overview/group-zone-equipment.tex

+
+\paragraph{Field: Space Return Air Node 1 Flow Rate Basis Node or NodeList Name}\label{field-space-return-air-flow-rate-basis-node-or-nodelist-name}
+
+The name of a node or list of nodes (\hyperref[nodelist]{NodeList}) that is used to calculate the return air flow rate for the first return air node in this space. The sum of the current flow rates for this node(s) multiplied by the Space Return Air Node 1 Flow Rate Fraction Schedule determines the return air flow rate. If this field is blank, then the base return air flow rate is the total supply inlet flow rate to the space less the total exhaust node flow rate from the space in the case of a single air loop serving this space. If there are multiple air loops serving this space, the base return air flow rate is governed by the corresponding supply inlet flow rate and the AirloopHVAC Design Return Air Flow Fraction of Supply Air Flow.


I assume this node name is the name of a space inlet node? When would this node not be a space inlet node?

Probably but not limited to that.

rraustad · 2023-08-18T17:26:19Z

doc/input-output-reference/src/overview/group-zone-equipment.tex

+      SPACE3-1 Out Node,     !- Space Return Air Node or NodeList Name
+      ,                      !- Space Return Air Node 1 Flow Rate Fraction Schedule Name
+      ;                      !- Space Return Air Node 1 Flow Rate Basis Node or NodeList Name
+\end{lstlisting}


There can be multiple space inlets, exhausts, and returns. But there is only 1 fraction schedule. It seems like spaces are currently limited to a single return node? or Return Air Node 1 is the only node that can have a fraction applied? I feel the urge to see "extensible" here.

Maybe someday

rraustad · 2023-08-18T17:33:40Z

doc/input-output-reference/src/overview/group-zone-equipment.tex

+    Zone 5-Remainder,        !- Space 3 Name
+    0.2,                     !- Space 3 Fraction {dimensionless}
+    Zone 5-Remainder In Node;  !- Space 3 Node Name
+\end{lstlisting}


Is there any connection between Space 1 Fraction in the mixer and the splitter? I think you told me that the splitter and mixer would NOT be used in unison (therefore the mixer and splitter fractions have no relationship) and are used based on the equipment type (e.g., PTAC vs ZoneExhaust).

No connection. For example, a fan coil could draw from one space and supply 2 or more spaces (once the mass balance code is implemented).

rraustad · 2023-08-18T17:39:09Z

idd/Energy+.idd.in

+       \key Ideal
+       \default SingleSpace
+   A7, \field Control Space Name
+       \note Used with SingleSpace thermostat control method


\note This field is only used when Thermostat Control Method = SingleSpace.

rraustad · 2023-08-18T17:43:05Z

idd/Energy+.idd.in

+       \begin-extensible
+       \required-field
+       \type object-list
+       \object-list SpaceNames


Does this object need a min-fields? I'm trying to figure out where I can stop providing inputs for this object.

Yes, minfilelds up to last field for space 1

OK, min-fields is already there and includes up to N1 since A10 is not required for non-airflow equipment.

rraustad · 2023-08-18T17:45:21Z

idd/Energy+.idd.in

+  A11, \field Space 2 Name
+       \required-field
+       \type object-list
+       \object-list SpaceNames


And I see that Space 2 Name is a required-field, as is Space 3 Name. I think that's a mistake. There can technically be only 1 space in a zone so requiring any fields after Space 1 might be troublesome?

Required is a mistake. If you want to make these idd changes please go ahead.

I will make the few changes to the idd. (notes, required-field, min-fields)

rraustad · 2023-08-18T17:46:01Z

idd/Energy+.idd.in

+       \required-field
+       \type node
+   A7, \field Space 2 Name
+       \required-field


Same comment on required-field here after Space 1.

rraustad · 2023-08-18T17:47:56Z

doc/input-output-reference/src/overview/group-zone-equipment.tex

@@ -212,14 +212,18 @@ \subsubsection{Inputs}\label{inputs-1-052}
 \begin{lstlisting}


The figure above should use actual object names so that users better understand the connections.

…ceSizingHVAC

rraustad · 2023-08-23T17:28:18Z

The only diffs here are with the 2 5ZoneAirCooledWithSpace* example files. I think this effort is ready to merge. I'm happy to do that later today just to not create a moving develop while CI is running.

rraustad

Reviewed code, commented and discussed, reviewed diffs.

rraustad · 2023-08-23T18:45:29Z

I just pulled develop and unit tests run successfully.

rraustad · 2023-08-23T20:01:17Z

5ZoneAirCooledWithSpacesHVAC.idf:

It appears that all the numbers are matching in these tables. Probably need to eventually make these more similar (e.g., include space volume, etc,). Thinking about the windows, does sunlight hit the space next to the window, or is distributed to all spaces?

And space type summary seems to make sense given the input in the Space object. The total row could eventually be filled in.

Space,
  Space 5 Office,          !- Name
  Zone 5,                  !- Zone Name
  autocalculate,           !- Ceiling Height {m}
  autocalculate,           !- Volume {m3}
  ,                        !- Floor Area {m2}
  Office,                  !- Space Type
  Std 62.1 Office Space,   !- Tag 1
  Std 90.1 Office-Open Plan;  !- Tag 2

rraustad · 2023-08-23T20:08:25Z

And Space 3* is peaking at different times, that's a good sign.

Comparing to zone cooling loads:

And Space 3 loads double when a zone multiplier of 2 is used:

rraustad · 2023-08-23T20:10:58Z

@Myoldmopar this is ready to merge. Let me know if you have other tests you want to run, otherwise I can merge this. My review is now complete.

Myoldmopar · 2023-08-23T20:16:27Z

I don't need anything else, merge away!

rraustad · 2023-08-23T20:26:05Z

Nice expansion of what spaces can do. Also, a 1.7% speed improvement.

Initial NFP

adb7535

mjwitte added NewFeature Includes code to add a new feature to EnergyPlus IDDChange Code changes impact the IDD file (cannot be merged after IO freeze) labels Apr 26, 2023

mjwitte added this to the EnergyPlus 23.2 IOFreeze milestone Apr 26, 2023

rraustad reviewed Apr 26, 2023

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rraustad reviewed Apr 27, 2023

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mjwitte added 2 commits May 5, 2023 15:35

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

196440c

…gHVAC

SpaceHVAC NFP Rev 1

007e50f

rraustad reviewed May 5, 2023

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EnergyArchmage reviewed May 17, 2023

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mjwitte added 5 commits May 19, 2023 12:57

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

5832cb5

…gHVAC

Start design [decent_ci_skip]

5d7c5ad

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

2b37000

…gHVAC

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

dc682fe

…gHVAC

More design [decent_ci_skip]

352563b

mjwitte added 12 commits July 17, 2023 09:35

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

49a40ac

…gHVAC

SpaceSizing - references and const

0e89cf5

SpaceSizing - more references and const

a3e6ec1

Prune TermUnitFinalZoneSizing

6ed366e

SpaceSizing - more const

dd02d04

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

139e165

…gHVAC

SpaceSizing - break apart UpdateZoneSizing

d219397

SpaceSizing - break apart UpdateZoneSizing cleanup

7739729

SpaceSizing - move some loose arrays into ZoneSizingData

061a6e9

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

c0ad1e7

…gHVAC

SpaceSizing - move more loose arrays into ZoneSizingData

2f100c7

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

670563f

…gHVAC

mjwitte added 4 commits August 16, 2023 17:14

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

f30f250

…gHVAC

Space HVAC - NonAirSysOutput

a1e2fd3

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

77eeb62

…gHVAC

Space HVAC - add SpaceHVAC:ZoneEquipmentMixer

69cd732

mjwitte commented Aug 17, 2023

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mjwitte added 3 commits August 17, 2023 21:39

Space HVAC - add exhaust fan to new testfile

603368e

Space HVAC - repairs

99ca30f

Space HVAC - fix broken ifs

8f0f792

Myoldmopar approved these changes Aug 18, 2023

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rraustad reviewed Aug 18, 2023

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rraustad added 2 commits August 18, 2023 15:46

A few minor changes to idd

89b3f28

Merge branch 'develop' of https://github.com/NREL/EnergyPlus into Spa…

96ebb6a

…ceSizingHVAC

rraustad approved these changes Aug 23, 2023

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rraustad merged commit 6120b0b into develop Aug 23, 2023
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rraustad deleted the SpaceSizingHVAC branch August 23, 2023 20:26

jmarrec mentioned this pull request Aug 25, 2023

E+ 23.2.0: Wrap SpaceHVAC:EquipmentConnections, SpaceHVAC:ZoneEquipmentSplitter, and SpaceHVAC:ZoneEquipmentMixer NREL/OpenStudio#4944

Open

This was referenced Sep 19, 2023

Space Sizing and HVAC part2 - Code cleanups #10174

Merged

Space Sizing and HVAC Part 3 #10205

Merged

Space Sizing and HVAC Documentation and Unit Test Updates #10239

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mjwitte mentioned this pull request Jun 17, 2024

Space Sizing and HVAC Part 4 #10566

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25 tasks

		state.dataSize->ZoneSizThermSetPtHi(state.dataSize->CurZoneEqNum));
		state.dataSize->TermUnitFinalZoneSizing(state.dataSize->CurTermUnitSizingNum).ZoneSizThermSetPtHi);

		@@ -438,6 +438,26 @@ namespace OutputReportPredefined {

		s->pdrSizing = newPreDefReport(state, "HVACSizingSummary", "Size", "HVAC Sizing Summary");

		s->pdstSpaceClSize = newPreDefSubTable(state, s->pdrSizing, "Space Sensible Cooling");

		if (state.dataHeatBal->doSpaceHeatBalanceSimulation && !state.dataGlobal->DoingSizing) {
		for (int spaceNum : state.dataHeatBal->Zone(ControlledZoneNum).spaceIndexes) {


		\paragraph{Field: Space Return Air Node 1 Flow Rate Fraction Schedule Name}\label{field-space-return-air-flow-rate-fraction-schedule-name}

		The name of a schedule to specify the return air flow rate for the first return air node as a fraction of the base return air. If the next field is blank, then the return air flow rate is the total supply inlet flow rate to the space less the total exhaust node flow rate from the space multiplied by this schedule name. If this field is left blank, the schedule defaults to 1.0 at all times.


		\paragraph{Field: Space Return Air Node 1 Flow Rate Basis Node or NodeList Name}\label{field-space-return-air-flow-rate-basis-node-or-nodelist-name}

		The name of a node or list of nodes (\hyperref[nodelist]{NodeList}) that is used to calculate the return air flow rate for the first return air node in this space. The sum of the current flow rates for this node(s) multiplied by the Space Return Air Node 1 Flow Rate Fraction Schedule determines the return air flow rate. If this field is blank, then the base return air flow rate is the total supply inlet flow rate to the space less the total exhaust node flow rate from the space in the case of a single air loop serving this space. If there are multiple air loops serving this space, the base return air flow rate is governed by the corresponding supply inlet flow rate and the AirloopHVAC Design Return Air Flow Fraction of Supply Air Flow.

		@@ -212,14 +212,18 @@ \subsubsection{Inputs}\label{inputs-1-052}
		\begin{lstlisting}

Extend Spaces to Sizing and HVAC #9982

Extend Spaces to Sizing and HVAC #9982

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mjwitte commented Apr 26, 2023 • edited by rraustad Loading

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