From 46d76883ee1ad22ecc9b1eaae3aaad1a8b040ee5 Mon Sep 17 00:00:00 2001
From: "Michael J. Witte" <mjwitte@gard.com>
Date: Mon, 7 Aug 2023 11:23:25 -0500
Subject: [PATCH] Space HVAC - fix space HB diffs for space system node

---
 src/EnergyPlus/ZoneEquipmentManager.cc       | 10 ++++++++++
 src/EnergyPlus/ZoneTempPredictorCorrector.cc | 17 +++++++++++------
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/EnergyPlus/ZoneEquipmentManager.cc b/src/EnergyPlus/ZoneEquipmentManager.cc
index 3f045061771..cc1fd65f939 100644
--- a/src/EnergyPlus/ZoneEquipmentManager.cc
+++ b/src/EnergyPlus/ZoneEquipmentManager.cc
@@ -4524,6 +4524,16 @@ void CalcZoneMassBalance(EnergyPlusData &state, bool const FirstHVACIteration)
             zoneNode.MassFlowRateMaxAvail = TotInletAirMassFlowRateMaxAvail;
             zoneNode.MassFlowRateMin = TotInletAirMassFlowRateMin;
             zoneNode.MassFlowRateMinAvail = TotInletAirMassFlowRateMinAvail;
+            if (state.dataHeatBal->doSpaceHeatBalance) {
+                for (int spaceNum : state.dataHeatBal->Zone(ZoneNum).spaceIndexes) {
+                    auto &spaceNode = Node(state.dataHeatBal->space(spaceNum).SystemZoneNodeNumber);
+                    spaceNode.MassFlowRate = TotInletAirMassFlowRate;
+                    spaceNode.MassFlowRateMax = TotInletAirMassFlowRateMax;
+                    spaceNode.MassFlowRateMaxAvail = TotInletAirMassFlowRateMaxAvail;
+                    spaceNode.MassFlowRateMin = TotInletAirMassFlowRateMin;
+                    spaceNode.MassFlowRateMinAvail = TotInletAirMassFlowRateMinAvail;
+                }
+            }
 
             // Calculate standard return air flow rate using default method of inlets minus exhausts adjusted for "balanced" exhaust flow
             Real64 StdTotalReturnMassFlow =
diff --git a/src/EnergyPlus/ZoneTempPredictorCorrector.cc b/src/EnergyPlus/ZoneTempPredictorCorrector.cc
index 51803ea04d0..68fd7a7bc4d 100644
--- a/src/EnergyPlus/ZoneTempPredictorCorrector.cc
+++ b/src/EnergyPlus/ZoneTempPredictorCorrector.cc
@@ -7160,6 +7160,11 @@ void ZoneSpaceHeatBalanceData::calcPredictedSystemLoad(EnergyPlusData &state, Re
     Real64 LoadToHeatingSetPoint = 0.0;
     Real64 LoadToCoolingSetPoint = 0.0;
 
+    int zoneNodeNum = thisZone.SystemZoneNodeNumber;
+    if (spaceNum > 0) {
+        zoneNodeNum = state.dataHeatBal->space(spaceNum).SystemZoneNodeNumber;
+    }
+
     switch (state.dataHeatBalFanSys->TempControlType(zoneNum)) {
     case DataHVACGlobals::ThermostatType::Uncontrolled:
         // Uncontrolled Zone
@@ -7307,8 +7312,8 @@ void ZoneSpaceHeatBalanceData::calcPredictedSystemLoad(EnergyPlusData &state, Re
             totalLoad = LoadToCoolingSetPoint;
         } else if (LoadToHeatingSetPoint <= 0.0 && LoadToCoolingSetPoint >= 0.0) { // deadband includes zero loads
             totalLoad = 0.0;
-            if (thisZone.SystemZoneNodeNumber > 0) {
-                ZoneSetPoint = state.dataLoopNodes->Node(thisZone.SystemZoneNodeNumber).Temp;
+            if (zoneNodeNum > 0) {
+                ZoneSetPoint = state.dataLoopNodes->Node(zoneNodeNum).Temp;
                 ZoneSetPoint = max(ZoneSetPoint, thisZoneThermostatSetPointLo); // trap out of deadband
                 ZoneSetPoint = min(ZoneSetPoint, thisZoneThermostatSetPointHi); // trap out of deadband
             }
@@ -7393,8 +7398,8 @@ void ZoneSpaceHeatBalanceData::calcPredictedSystemLoad(EnergyPlusData &state, Re
         } else if (LoadToHeatingSetPoint <= 0.0 && LoadToCoolingSetPoint >= 0.0) { // deadband includes zero loads
             // this turns out to cause instabilities sometimes? that lead to setpoint errors if predictor is off.
             totalLoad = 0.0;
-            if (thisZone.SystemZoneNodeNumber > 0) {
-                ZoneSetPoint = state.dataLoopNodes->Node(thisZone.SystemZoneNodeNumber).Temp;
+            if (zoneNodeNum > 0) {
+                ZoneSetPoint = state.dataLoopNodes->Node(zoneNodeNum).Temp;
                 ZoneSetPoint = max(ZoneSetPoint, thisZoneThermostatSetPointLo); // trap out of deadband
                 ZoneSetPoint = min(ZoneSetPoint, thisZoneThermostatSetPointHi); // trap out of deadband
             }
@@ -7504,8 +7509,8 @@ void ZoneSpaceHeatBalanceData::calcPredictedSystemLoad(EnergyPlusData &state, Re
     }
 
     // If the ZoneNodeNum has been set for a Controlled Zone, then the zone setpoint is placed on the node.
-    if (thisZone.SystemZoneNodeNumber > 0) {
-        state.dataLoopNodes->Node(thisZone.SystemZoneNodeNumber).TempSetPoint = ZoneSetPoint;
+    if (zoneNodeNum > 0) {
+        state.dataLoopNodes->Node(zoneNodeNum).TempSetPoint = ZoneSetPoint;
     }
 
     state.dataZoneEnergyDemand->Setback(zoneNum) = (ZoneSetPoint > this->ZoneSetPointLast);