Merge pull request #4754 from NREL/88621024-ElectricLoadCenterStorage…

…Battery-Crash 88621024 electric load center storage battery crash
NREL · Mar 11, 2015 · 6dd7037 · 6dd7037 · nrel-bot · Mar 11, 2015
2 parents 29b69b1 + bcc7daf
commit 6dd7037
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Showing 4 changed files with 147 additions and 21 deletions.
diff --git a/src/EnergyPlus/ManageElectricPower.cc b/src/EnergyPlus/ManageElectricPower.cc
@@ -3029,26 +3029,9 @@ namespace ManageElectricPower {
 
 				Pw = tmpPdraw / Numbattery;
 				q0 = ElecStorage( ElecStorNum ).LastTimeStepAvailable + ElecStorage( ElecStorNum ).LastTimeStepBound;
-				I0 = 10.0; // Initial assumption
-				T0 = qmax / I0; // Initial Assumption
-				qmaxf = qmax * k * c * T0 / ( 1.0 - std::exp( -k * T0 ) + c * ( k * T0 - 1.0 + std::exp( -k * T0 ) ) ); //Initial calculation of a function qmax(I)
-				Xf = ( qmax - q0 ) / qmaxf;
-				Ef = E0c + CurveValue( ElecStorage( ElecStorNum ).DischargeCurveNum, Xf ); //E0d+Ac*Xf+Cc*X/(Dc-Xf)
-				Volt = Ef - I0 * InternalR;
-				Inew = Pw / Volt;
-				Tnew = qmaxf / Inew;
-				error = 1.0;
-
-				while ( error > 0.0001 ) { //Iteration process to get converged current(I)
-					I0 = Inew;
-					T0 = Tnew;
-					qmaxf = qmax * k * c * T0 / ( 1.0 - std::exp( -k * T0 ) + c * ( k * T0 - 1.0 + std::exp( -k * T0 ) ) );
-					Xf = ( qmax - q0 ) / qmaxf;
-					Ef = E0c + CurveValue( ElecStorage( ElecStorNum ).DischargeCurveNum, Xf ); //E0c+Ad*Xf+Cd*X/(Dd-Xf)
-					Volt = Ef - I0 * InternalR;
-					Inew = Pw / Volt;
-					Tnew = qmaxf / Inew;
-					error = std::abs( Inew - I0 );
+				bool ok = determineCurrentForBatteryDischarge( I0, T0, Volt, Pw, q0, ElecStorage( ElecStorNum ).DischargeCurveNum, k, c, qmax, E0c, InternalR );
+				if ( !ok ){
+					ShowFatalError( "ElectricLoadCenter:Storage:Battery named=\"" + ElecStorage( ElecStorNum ).Name + "\". Battery discharge current could not be estimated due to iteration limit reached. " );
 				}
 
 				dividend = k * ElecStorage( ElecStorNum ).LastTimeStepAvailable * std::exp( -k * TimeStepSys ) + q0 * k * c * ( 1.0 - std::exp( -k * TimeStepSys ) );
@@ -3192,6 +3175,82 @@ namespace ManageElectricPower {
 
 	//*****************************************************************************************************************
 
+	bool 
+	determineCurrentForBatteryDischarge( 
+		Real64& curI0, 
+		Real64& curT0, 
+		Real64& curVolt,
+		Real64 const Pw, 
+		Real64 const q0,
+		int const CurveNum,
+		Real64 const k,
+		Real64 const c,
+		Real64 const qmax,
+		Real64 const E0c,
+		Real64 const InternalR )
+	{
+		// FUNCTION INFORMATION:
+		//       AUTHOR         B. Griffith
+		//       DATE WRITTEN   June-August 2008
+		//       MODIFIED       BG May 2009, added EMS
+		//                      BN (FSEC) Feb 2010 (pass out two storage values)
+		//                      Y. KyungTae & W. Wang July-August, 2011 Added a battery model
+		//       RE-ENGINEERED  Jason Glazer, GARD Analytics, February 2015, refactor charge calculation into a function
+
+		// PURPOSE OF THIS FUNCTION:
+		// Calculate the current for battery discharge in a separate function so that it could be called from the unit tests
+
+		// METHODOLOGY EMPLOYED:
+		// na
+
+		// REFERENCES:
+		// na
+
+		// Using/Aliasing
+		using CurveManager::CurveValue;
+
+		// Locals
+		// FUNCTION ARGUMENT DEFINITIONS:
+
+		// INTERFACE BLOCK SPECIFICATIONS:
+		// na
+
+		// DERIVED TYPE DEFINITIONS:
+		// na
+
+		// FUNCTION LOCAL VARIABLE DECLARATIONS:
+		curI0 = 10.0; // Initial assumption
+		curT0 = qmax / curI0; // Initial Assumption
+		Real64 qmaxf = qmax * k * c * curT0 / ( 1.0 - std::exp( -k * curT0 ) + c * ( k * curT0 - 1.0 + std::exp( -k * curT0 ) ) ); //Initial calculation of a function qmax(I)
+		Real64 Xf = ( qmax - q0 ) / qmaxf;
+		Real64 Ef = E0c + CurveValue( CurveNum, Xf ); //E0d+Ac*Xf+Cc*X/(Dc-Xf)
+		curVolt = Ef - curI0 * InternalR;
+		Real64 Inew = Pw / curVolt;
+		Real64 Tnew = qmaxf / Inew;
+		Real64 error = 1.0;
+		int countForIteration = 0;
+		bool exceedIterationLimit = false;
+
+		while ( error > 0.0001 ) { //Iteration process to get converged current(I)
+			curI0 = Inew;
+			curT0 = Tnew;
+			qmaxf = qmax * k * c * curT0 / ( 1.0 - std::exp( -k * curT0 ) + c * ( k * curT0 - 1.0 + std::exp( -k * curT0 ) ) );
+			Xf = ( qmax - q0 ) / qmaxf;
+			Ef = E0c + CurveValue( CurveNum, Xf ); //E0c+Ad*Xf+Cd*X/(Dd-Xf)
+			curVolt = Ef - curI0 * InternalR;
+			Inew = Pw / curVolt;
+			Tnew = qmaxf / Inew;
+			error = std::abs( Inew - curI0 );
+			countForIteration++;
+			if ( countForIteration > 1000 ){
+				exceedIterationLimit = true;
+				break;
+			}
+		}
+		return (!exceedIterationLimit);
+	}
+
+
 	void
 	FigureElectricalStorageZoneGains()
 	{

diff --git a/src/EnergyPlus/ManageElectricPower.hh b/src/EnergyPlus/ManageElectricPower.hh
@@ -1029,6 +1029,21 @@ namespace ManageElectricPower {
 
 	//*****************************************************************************************************************
 
+	bool
+		determineCurrentForBatteryDischarge(
+		Real64& curI0,
+		Real64& curT0,
+		Real64& curVolt,
+		Real64 const Pw,
+		Real64 const q0,
+		int const CurveNum,
+		Real64 const k,
+		Real64 const c,
+		Real64 const qmax,
+		Real64 const E0c,
+		Real64 const InternalR
+	);
+
 	void
 	FigureElectricalStorageZoneGains();
 

diff --git a/tst/EnergyPlus/unit/CMakeLists.txt b/tst/EnergyPlus/unit/CMakeLists.txt
@@ -12,8 +12,9 @@ set( test_src
   FluidCoolers.unit.cc
   GroundHeatExchangers.unit.cc
   HeatBalanceManager.unit.cc
-  HVACStandaloneERV.unit.cc
   Humidifiers.unit.cc
+  HVACStandaloneERV.unit.cc
+  ManageElectricPower.unit.cc
   MixedAir.unit.cc
   PurchasedAirManager.unit.cc
   OutputProcessor.unit.cc

diff --git a/tst/EnergyPlus/unit/ManageElectricPower.unit.cc b/tst/EnergyPlus/unit/ManageElectricPower.unit.cc
@@ -0,0 +1,51 @@
+// EnergyPlus::ExteriorEnergyUse Unit Tests
+
+// Google Test Headers
+#include <gtest/gtest.h>
+
+// EnergyPlus Headers
+#include <EnergyPlus/ExteriorEnergyUse.hh>
+#include <EnergyPlus/ManageElectricPower.hh>
+#include <EnergyPlus/CurveManager.hh>
+
+using namespace EnergyPlus;
+using namespace EnergyPlus::ManageElectricPower;
+using namespace EnergyPlus::CurveManager;
+using namespace ObjexxFCL;
+using namespace DataGlobals;
+
+TEST( ManageElectricPowerTest, BatteryDischargeTest )
+{
+
+	NumCurves = 1;
+	PerfCurve.allocate( NumCurves );
+	PerfCurve( 1 ).CurveType = CurveType_RectangularHyperbola1;
+	PerfCurve( 1 ).InterpolationType = EvaluateCurveToLimits;
+	PerfCurve( 1 ).Coeff1 = 0.0899;
+	PerfCurve( 1 ).Coeff2 = -98.24;
+	PerfCurve( 1 ).Coeff3 = -.0082;
+	int CurveNum1 = 1;
+	Real64 k = 0.5874;
+	Real64 c = 0.37;
+	Real64 qmax = 86.1;
+	Real64 E0c = 12.6;
+	Real64 InternalR = 0.054;
+
+	Real64 I0 = 0.159;
+	Real64 T0 = 537.9;
+	Real64 Volt = 12.59;
+	Real64 Pw = 2.0;
+	Real64 q0 = 60.2;
+
+	EXPECT_TRUE( determineCurrentForBatteryDischarge( I0, T0, Volt, Pw, q0, CurveNum1, k, c, qmax, E0c, InternalR ) );
+
+	I0 = -222.7;
+	T0 = -0.145;
+	Volt = 24.54;
+	Pw = 48000;
+	q0 = 0;
+
+	EXPECT_FALSE( determineCurrentForBatteryDischarge( I0, T0, Volt, Pw, q0, CurveNum1, k, c, qmax, E0c, InternalR ) );
+
+	PerfCurve.deallocate();
+}