Fix #10302 - CalcEquipmentFlowRates assert failure due to out of bounds std::array indexing

src/EnergyPlus/SolarCollectors.cc

@@ -1979,7 +1979,7 @@ namespace SolarCollectors {
             CondOfAir = Conductivity[Index];
             PrOfAir = Pr[Index];
             DensOfAir = Density[Index];
-        } else if (Index > NumOfPropDivisions) {
+        } else if (Index >= NumOfPropDivisions) { // 0-index, hence MaxIndex = NumOfPropDivisions - 1
             Index = NumOfPropDivisions - 1;
             VisDOfAir = Mu[Index];
             CondOfAir = Conductivity[Index];

src/EnergyPlus/SolarCollectors.hh

@@ -54,7 +54,9 @@
 
 // EnergyPlus Headers
 #include <EnergyPlus/DataGlobals.hh>
+#include <EnergyPlus/EPVector.hh>
 #include <EnergyPlus/EnergyPlus.hh>
+#include <EnergyPlus/Plant/DataPlant.hh>
 #include <EnergyPlus/PlantComponent.hh>
 
 namespace EnergyPlus {

tst/EnergyPlus/unit/CMakeLists.txt

@@ -221,6 +221,7 @@ set(test_src
     SizeWaterHeatingCoil.unit.cc
     SizingAnalysisObjects.unit.cc
     SizingManager.unit.cc
+    SolarCollectors.unit.cc
     SolarShading.unit.cc
     Standard621SimplifiedProcedure.unit.cc
     StandardRatings.unit.cc

tst/EnergyPlus/unit/SolarCollectors.unit.cc

@@ -0,0 +1,78 @@
+// EnergyPlus, Copyright (c) 1996-2024, The Board of Trustees of the University of Illinois,
+// The Regents of the University of California, through Lawrence Berkeley National Laboratory
+// (subject to receipt of any required approvals from the U.S. Dept. of Energy), Oak Ridge
+// National Laboratory, managed by UT-Battelle, Alliance for Sustainable Energy, LLC, and other
+// contributors. All rights reserved.
+//
+// NOTICE: This Software was developed under funding from the U.S. Department of Energy and the
+// U.S. Government consequently retains certain rights. As such, the U.S. Government has been
+// granted for itself and others acting on its behalf a paid-up, nonexclusive, irrevocable,
+// worldwide license in the Software to reproduce, distribute copies to the public, prepare
+// derivative works, and perform publicly and display publicly, and to permit others to do so.
+//
+// Redistribution and use in source and binary forms, with or without modification, are permitted
+// provided that the following conditions are met:
+//
+// (1) Redistributions of source code must retain the above copyright notice, this list of
+//     conditions and the following disclaimer.
+//
+// (2) Redistributions in binary form must reproduce the above copyright notice, this list of
+//     conditions and the following disclaimer in the documentation and/or other materials
+//     provided with the distribution.
+//
+// (3) Neither the name of the University of California, Lawrence Berkeley National Laboratory,
+//     the University of Illinois, U.S. Dept. of Energy nor the names of its contributors may be
+//     used to endorse or promote products derived from this software without specific prior
+//     written permission.
+//
+// (4) Use of EnergyPlus(TM) Name. If Licensee (i) distributes the software in stand-alone form
+//     without changes from the version obtained under this License, or (ii) Licensee makes a
+//     reference solely to the software portion of its product, Licensee must refer to the
+//     software as "EnergyPlus version X" software, where "X" is the version number Licensee
+//     obtained under this License and may not use a different name for the software. Except as
+//     specifically required in this Section (4), Licensee shall not use in a company name, a
+//     product name, in advertising, publicity, or other promotional activities any name, trade
+//     name, trademark, logo, or other designation of "EnergyPlus", "E+", "e+" or confusingly
+//     similar designation, without the U.S. Department of Energy's prior written consent.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
+// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+// Google Test Headers
+#include <gtest/gtest.h>
+
+// EnergyPlus Headers
+#include "Fixtures/EnergyPlusFixture.hh"
+#include <EnergyPlus/SolarCollectors.hh>
+
+#include <cmath>
+
+using namespace EnergyPlus;
+
+TEST_F(EnergyPlusFixture, CalcConvCoeffBetweenPlates)
+{
+    constexpr Real64 TempSurf1 = 251.0; // temperature of surface 1
+    constexpr Real64 TempSurf2 = 26.5;  // temperature of surface 2
+
+    constexpr Real64 Tref = 0.5 * (TempSurf1 + TempSurf2);
+
+    constexpr Real64 maxArrayTemp = 126.85; // This is the max temperature in the `Temps` array that stores the correlation temps
+    EXPECT_TRUE(Tref > maxArrayTemp);
+
+    // Irrelevant to this test
+    constexpr Real64 AirGap = 0.05;  // characteristic length [m]
+    constexpr Real64 CosTilt = 0.87; // cosine of surface tilt angle relative to the horizontal
+    constexpr Real64 SinTilt = 0.80; // sine of surface tilt angle relative to the horizontal
+
+    Real64 hConvCoef = EnergyPlus::SolarCollectors::CollectorData::CalcConvCoeffBetweenPlates(TempSurf1, TempSurf2, AirGap, CosTilt, SinTilt);
+    EXPECT_FALSE(std::isnan(hConvCoef));
+    EXPECT_TRUE(std::isfinite(hConvCoef));
+    EXPECT_NEAR(4.71593, hConvCoef, 0.001);
+}