fix expm1 math

NREL · Dec 25, 2024 · 8956557 · 8956557 · nrel-bot-2c · Dec 25, 2024
1 parent 62fd1a4
commit 8956557
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Showing 2 changed files with 4 additions and 4 deletions.
diff --git a/src/EnergyPlus/HeatRecovery.cc b/src/EnergyPlus/HeatRecovery.cc
@@ -3133,7 +3133,7 @@ namespace HeatRecovery {
             } break;
             case HXConfiguration::CrossFlowBothUnmixed: { // CROSS FLOW BOTH UNMIXED
                 Temp = Z * std::pow(NTU, -0.22);
-                Eps = 1.0 - std::expm1(std::exp(-NTU * Temp) / Temp);
+                Eps = 1.0 - std::exp(std::expm1(-NTU * Temp) / Temp);
             } break;
             case HXConfiguration::CrossFlowOther: { // CROSS FLOW, Cmax MIXED, Cmin UNMIXED
                 Eps = (1.0 - std::exp(-Z * (1.0 - std::exp(-NTU)))) / Z;
@@ -3273,7 +3273,7 @@ namespace HeatRecovery {
         int SolFla;                  // Flag of solver
         Real64 constexpr NTU0(0.0);  // lower bound for NTU
         Real64 constexpr NTU1(50.0); // upper bound for NTU
-        auto f = [Eps, Z](Real64 const NTU) { return 1.0 - std::expm1(std::exp(-std::pow(NTU, 0.78) * Z) / Z * std::pow(NTU, 0.22)) - Eps; };
+        auto f = [Eps, Z](Real64 const NTU) { return 1.0 - std::exp(std::expm1(-std::pow(NTU, 0.78) * Z) / Z * std::pow(NTU, 0.22)) - Eps; };
         General::SolveRoot(state, Acc, MaxIte, SolFla, NTU, f, NTU0, NTU1);
 
         if (SolFla == -2) {

diff --git a/src/EnergyPlus/WaterThermalTanks.cc b/src/EnergyPlus/WaterThermalTanks.cc
@@ -8084,8 +8084,8 @@ void WaterThermalTankData::CalcWaterThermalTankStratified(EnergyPlusData &state)
                             FinalFactorMixing = dt / NodeCapacitance;
                             AvgFactorMixing = FinalFactorMixing / 2.0;
                         } else {
-                            FinalFactorMixing = expm1(A[k] * dt) / A[k] / NodeCapacitance;
-                            AvgFactorMixing = (expm1(A[k] * dt) / A[k] / dt - 1.0) / A[k] / NodeCapacitance;
+                            FinalFactorMixing = std::expm1(A[k] * dt) / A[k] / NodeCapacitance;
+                            AvgFactorMixing = (std::expm1(A[k] * dt) / A[k] / dt - 1.0) / A[k] / NodeCapacitance;
                         }
                         const Real64 Q_AdiabaticMixing = (Tmixed - Tfinal[k]) / FinalFactorMixing;
                         Tfinal[k] = Tmixed;