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Merged
cpaulgilman merged 13 commits into from
Jul 23, 2025
Merged

SSC: Add builtin snow depth array, support varying periods for this array. #1335

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a4830d7
minimum working example of using snow depth with user input. Not robu…
berg-michael May 14, 2025
bfcac80
Merge branch 'develop' into nohrsc_snow_data
berg-michael Jun 2, 2025
a1ce527
allow snow_array default to be of length 1 for testing (repeat 8760 t…
berg-michael Jun 2, 2025
d27be5f
first pass at editing tests to reflect new variables
berg-michael Jun 2, 2025
295a431
Use boolean operators correctly
berg-michael Jun 2, 2025
e012eaa
add new snow variables to tranche of pv tests
berg-michael Jun 2, 2025
f8da74e
add new defaults to pvyield common data
berg-michael Jun 2, 2025
cff422f
add snow related vars to more tests- these tests have presaved json i…
berg-michael Jun 2, 2025
e7d0903
JSON-based tests: put new vars in test data, and remove them from tes…
berg-michael Jun 3, 2025
50ce79f
If snow data and weather file have different periods that are divisib…
berg-michael Jul 2, 2025
8d9f627
add tests of snow data, including shorter than/longer than weather fi…
berg-michael Jul 2, 2025
2fe3bb8
Fix bug that led to OOB when running a lifetime (vs one year) simulat…
berg-michael Jul 3, 2025
79eff5b
Merge branch 'develop' into nohrsc_snow_data
cpaulgilman Jul 18, 2025
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38 changes: 37 additions & 1 deletion shared/lib_pv_io_manager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -206,6 +206,41 @@ Irradiance_IO::Irradiance_IO(compute_module* cm, std::string cmName)
throw exec_error(cmName, "Albedos must be greater than zero and less than one in the monthly uniform albedo matrix.");
}
}
// read in the user entered snow data

std::vector<double> orig_snow_array = cm->as_vector_double("snow_array");
// align the user entered snow data with the weather file data
std::vector<double> aligned_snow_array;
aligned_snow_array.reserve(numberOfWeatherFileRecords);
if (orig_snow_array.size() == 1) {
aligned_snow_array.resize(numberOfWeatherFileRecords);
std::fill(aligned_snow_array.begin(), aligned_snow_array.end(), orig_snow_array[0]);
}
else if (orig_snow_array.size() < numberOfWeatherFileRecords) {
if (numberOfWeatherFileRecords % orig_snow_array.size() != 0) {
throw exec_error(cmName, "Snow depth array and weather file must have divisible periods.");
}
size_t mult = numberOfWeatherFileRecords / orig_snow_array.size();
for (double depth : orig_snow_array) {
for (size_t j = 0; j < mult; j++) {
aligned_snow_array.push_back(depth);
}
}
}
else if (orig_snow_array.size() == numberOfWeatherFileRecords) {
aligned_snow_array = orig_snow_array;
}
else {
if (orig_snow_array.size() % numberOfWeatherFileRecords != 0) {
throw exec_error(cmName, "Snow depth array and weather file must have divisible periods.");
}
size_t mult = orig_snow_array.size() / numberOfWeatherFileRecords;
for (size_t i = 0; i < orig_snow_array.size(); i += mult) {
aligned_snow_array.push_back(orig_snow_array[i]);
}
}
userSpecifiedSnowDepth = aligned_snow_array;


checkWeatherFile(cm, cmName);
}
Expand Down Expand Up @@ -307,7 +342,7 @@ void Irradiance_IO::AllocateOutputs(compute_module* cm)
else {
p_weatherFileAlbedo = cm->allocate("alb", numberOfWeatherFileRecords);
}
p_weatherFileSnowDepth = cm->allocate("snowdepth", numberOfWeatherFileRecords);
p_snowDepth = cm->allocate("snowdepth", numberOfWeatherFileRecords);

// If using input POA, must have POA for every subarray or assume POA applies to each subarray
for (size_t subarray = 0; subarray != numberOfSubarrays; subarray++) {
Expand Down Expand Up @@ -725,6 +760,7 @@ PVSystem_IO::PVSystem_IO(compute_module* cm, std::string cmName, Simulation_IO*
enableDCLifetimeLosses = cm->as_boolean("en_dc_lifetime_losses");
enableACLifetimeLosses = cm->as_boolean("en_ac_lifetime_losses");
enableSnowModel = cm->as_boolean("en_snow_model");
useWeatherFileSnow = cm->as_boolean("use_snow_weather_file");

// The shared inverter of the PV array and a tightly-coupled DC connected battery
std::unique_ptr<SharedInverter> tmpSharedInverter(new SharedInverter(Inverter->inverterType, numberOfInverters, &Inverter->sandiaInverter, &Inverter->partloadInverter, &Inverter->ondInverter, numberOfInvertersClipping));
Expand Down
4 changes: 3 additions & 1 deletion shared/lib_pv_io_manager.h
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Expand Up @@ -234,6 +234,7 @@ struct Irradiance_IO
flag useSpatialAlbedos; /// Specify whether to use spatial albedos
std::vector<double> userSpecifiedMonthlyAlbedo; /// User can provide monthly uniform ground albedo values (0-1)
util::matrix_t<double> userSpecifiedMonthlySpatialAlbedos; /// User can provide monthly spatial ground albedo values (0-1), [month, location]
std::vector<double> userSpecifiedSnowDepth; /// User can provide hourly snow depth data (cm)

// Irradiance data Outputs (p_ is just a convention to organize all pointer outputs)
ssc_number_t * p_weatherFileGHI; /// The Global Horizonal Irradiance from the weather file [W/m2]
Expand All @@ -245,7 +246,7 @@ struct Irradiance_IO
ssc_number_t * p_weatherFileAmbientTemp; /// The ambient temperature from the weather file [C]
ssc_number_t * p_weatherFileAlbedo; /// The ground albedo from the weather file
ssc_number_t* p_weatherFileAlbedoSpatial; /// The ground albedo from the weather file and spatial matrix input
ssc_number_t * p_weatherFileSnowDepth; /// The snow depth from the weather file
ssc_number_t * p_snowDepth; /// The snow depth from the weather file or user input array
ssc_number_t * p_IrradianceCalculated[3]; /// The calculated components of the irradiance [W/m2]
ssc_number_t * p_sunZenithAngle; /// The calculate sun zenith angle [degrees]
ssc_number_t * p_sunAltitudeAngle; /// The calculated sun altitude angle [degrees]
Expand Down Expand Up @@ -297,6 +298,7 @@ struct PVSystem_IO
flag enableDCLifetimeLosses;
flag enableACLifetimeLosses;
flag enableSnowModel;
flag useWeatherFileSnow;

int stringsInParallel;
double ratedACOutput; ///< AC Power rating for whole system (all inverters)
Expand Down
29 changes: 24 additions & 5 deletions ssc/cmod_pvsamv1.cpp
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Expand Up @@ -64,7 +64,8 @@ static var_info _cm_vtab_pvsamv1[] = {
// misc inputs
{SSC_INPUT, SSC_NUMBER, "en_snow_model", "Toggle snow loss estimation", "0/1", "", "Losses", "?=0", "BOOLEAN", "" },
{ SSC_INPUT, SSC_NUMBER, "snow_slide_coefficient", "Snow Slide Coefficient", "", "", "Losses", "?=1.97", "", "" },

{SSC_INPUT, SSC_ARRAY, "snow_array", "Hourly snow depth ", "cm", "", "Losses", "?", "", ""},
{SSC_INPUT, SSC_NUMBER, "use_snow_weather_file", "Use the snow depth from the weather file", "0/1", "0=user-specified,1=weatherfile", "Losses", "*", "", ""},
{SSC_INPUT, SSC_NUMBER, "system_capacity", "DC Nameplate capacity", "kWdc", "", "System Design", "*", "", "" },
{SSC_INPUT, SSC_NUMBER, "use_wf_albedo", "Use albedo in weather file if provided", "0/1", "0=user-specified,1=weatherfile", "Solar Resource", "?=1", "BOOLEAN", "" },
{SSC_INPUT, SSC_NUMBER, "use_spatial_albedos", "Use spatial albedo values", "0/1", "0=no,1=yes", "Solar Resource", "?=0", "BOOLEAN", "" },
Expand Down Expand Up @@ -620,7 +621,7 @@ static var_info _cm_vtab_pvsamv1[] = {
{ SSC_OUTPUT, SSC_ARRAY, "tdry", "Weather file ambient temperature", "C", "", "Time Series", "*", "", "" },
{ SSC_OUTPUT, SSC_ARRAY, "alb", "Albedo", "", "", "Time Series", "", "", "" },
{ SSC_OUTPUT, SSC_MATRIX, "alb_spatial", "Albedo spatial", "", "", "Time Series", "", "", "" },
{ SSC_OUTPUT, SSC_ARRAY, "snowdepth", "Weather file snow depth", "cm", "", "Time Series", "", "", "" },
{ SSC_OUTPUT, SSC_ARRAY, "snowdepth", "Snow depth", "cm", "", "Time Series", "", "", "" },

// calculated sun position data
{ SSC_OUTPUT, SSC_ARRAY, "sol_zen", "Sun zenith angle", "degrees", "", "Time Series", "*", "", "" },
Expand Down Expand Up @@ -2445,9 +2446,20 @@ void cm_pvsamv1::exec()
if (PVSystem->enableSnowModel)
{
float smLoss = 0.0f;

float snowDep = 0.0f;
// Now we have the option to either use weather file snow data or user input snow data
if (PVSystem->useWeatherFileSnow)
{
// Use weather file snow data
snowDep = (float)wf.snow;
}
else
{
// Use user input snow data
snowDep = Irradiance->userSpecifiedSnowDepth[idx % nrec];
}
if (!Subarrays[nn]->snowModel.getLoss((float)(Subarrays[nn]->poa.poaBeamFront + Subarrays[nn]->poa.poaDiffuseFront + Subarrays[nn]->poa.poaGroundFront + ipoa_rear_after_losses[nn]),
(float)Subarrays[nn]->poa.surfaceTiltDegrees, (float)wf.wspd, (float)wf.tdry, (float)wf.snow, sunup, 1.0f / step_per_hour, smLoss))
(float)Subarrays[nn]->poa.surfaceTiltDegrees, (float)wf.wspd, (float)wf.tdry, snowDep, sunup, 1.0f / step_per_hour, smLoss))
{
if (!Subarrays[nn]->snowModel.good)
throw exec_error("pvsamv1", Subarrays[nn]->snowModel.msg);
Expand Down Expand Up @@ -2544,7 +2556,14 @@ void cm_pvsamv1::exec()
{
Irradiance->p_weatherFileWindSpeed[idx] = (ssc_number_t)wf.wspd;
Irradiance->p_weatherFileAmbientTemp[idx] = (ssc_number_t)wf.tdry;
Irradiance->p_weatherFileSnowDepth[idx] = (ssc_number_t)wf.snow;
double snoDep;
if (PVSystem->useWeatherFileSnow) {
snoDep = (ssc_number_t)wf.snow;
}
else {
snoDep = Irradiance->userSpecifiedSnowDepth[idx % nrec];
}
Irradiance->p_snowDepth[idx] = snoDep;
Irradiance->p_sunZenithAngle[idx] = (ssc_number_t)solzen;
Irradiance->p_sunAltitudeAngle[idx] = (ssc_number_t)solalt;
Irradiance->p_sunAzimuthAngle[idx] = (ssc_number_t)solazi;
Expand Down
2 changes: 2 additions & 0 deletions test/input_cases/general_data/pvsmoothing_Phoenix_Validation_alloptions.json
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6 changes: 6 additions & 0 deletions test/input_cases/pvsamv1_common_data.cpp
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Expand Up @@ -68,6 +68,9 @@ void pvsamv_nofinancial_default(ssc_data_t& data)
ssc_data_set_number(data, "transformer_no_load_loss", 0);
ssc_data_set_number(data, "transformer_load_loss", 0);
ssc_data_set_number(data, "en_snow_model", 0);
ssc_data_set_number(data, "use_snow_weather_file", 1);
ssc_number_t snow_array[1] = { 0 };
ssc_data_set_array(data, "snow_array", snow_array, 1);
ssc_data_set_number(data, "system_capacity", 4.6928696632385254);
ssc_data_set_number(data, "use_wf_albedo", 0);
ssc_number_t p_albedo[12] = { 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224 };
Expand Down Expand Up @@ -568,6 +571,9 @@ void pvsamv1_with_residential_default(ssc_data_t& data)
ssc_data_set_number(data, "use_wf_albedo", 0);
ssc_number_t p_albedo[12] = { 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224 };
ssc_data_set_array(data, "albedo", p_albedo, 12);
ssc_data_set_number(data, "use_snow_weather_file", 1);
ssc_number_t snow_array[1] = { 0 };
ssc_data_set_array(data, "snow_array", snow_array, 1);
ssc_data_set_number(data, "irrad_mode", 0);
ssc_data_set_number(data, "sky_model", 2);
ssc_data_set_number(data, "inverter_count", 1);
Expand Down
12 changes: 12 additions & 0 deletions test/input_cases/pvyield_common_data.h
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Expand Up @@ -58,6 +58,9 @@ void pvyield_no_financial_meteo(ssc_data_t& data)
ssc_data_set_number(data, "transformer_no_load_loss", 0);
ssc_data_set_number(data, "transformer_load_loss", 0);
ssc_data_set_number(data, "en_snow_model", 0);
ssc_data_set_number(data, "use_snow_weather_file", 1);
ssc_number_t snow_array[1] = { 0 };
ssc_data_set_array(data, "snow_array", snow_array, 1);
ssc_data_set_number(data, "system_capacity", 4182.357);
ssc_data_set_number(data, "use_wf_albedo", 0);
ssc_number_t p_albedo[12] = { 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224 };
Expand Down Expand Up @@ -506,6 +509,9 @@ void pvyield_bifacial_case(ssc_data_t& data)
ssc_data_set_number(data, "transformer_no_load_loss", 0);
ssc_data_set_number(data, "transformer_load_loss", 0);
ssc_data_set_number(data, "en_snow_model", 0);
ssc_data_set_number(data, "use_snow_weather_file", 1);
ssc_number_t snow_array[1] = { 0 };
ssc_data_set_array(data, "snow_array", snow_array, 1);
ssc_data_set_number(data, "system_capacity", 206200);
ssc_data_set_number(data, "use_wf_albedo", 1);
ssc_number_t p_albedo[12] = { 0.005, 0.005, 0.004, 0.006, 0.015, 0.042, 0.083, 0.003, 0.066, 0.049, 0.013, 0.007 };
Expand Down Expand Up @@ -942,6 +948,9 @@ void pvyield_user_support_80603_meteo(ssc_data_t& data)
ssc_data_set_number(data, "transformer_no_load_loss", 0);
ssc_data_set_number(data, "transformer_load_loss", 0);
ssc_data_set_number(data, "en_snow_model", 0);
ssc_data_set_number(data, "use_snow_weather_file", 1);
ssc_number_t snow_array[1] = { 0 };
ssc_data_set_array(data, "snow_array", snow_array, 1);
ssc_data_set_number(data, "system_capacity", 4182.357);
ssc_data_set_number(data, "use_wf_albedo", 0);
ssc_number_t p_albedo[12] = { 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224 };
Expand Down Expand Up @@ -1380,6 +1389,9 @@ void pvyield_user_support_80603_AZ(ssc_data_t& data)
ssc_data_set_number(data, "transformer_no_load_loss", 0);
ssc_data_set_number(data, "transformer_load_loss", 0);
ssc_data_set_number(data, "en_snow_model", 0);
ssc_data_set_number(data, "use_snow_weather_file", 1);
ssc_number_t snow_array[1] = { 0 };
ssc_data_set_array(data, "snow_array", snow_array, 1);
ssc_data_set_number(data, "system_capacity", 4182.357);
ssc_data_set_number(data, "use_wf_albedo", 0);
ssc_number_t p_albedo[12] = { 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224, 0.20000000298023224 };
Expand Down
2 changes: 2 additions & 0 deletions test/input_json/PV_Batt_MP.json
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2 changes: 2 additions & 0 deletions test/input_json/solesca/test_fixed_tilt_racking.json
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Expand Up @@ -38,6 +38,8 @@
"transformer_no_load_loss": 0.0,
"transformer_load_loss": 0.0,
"en_snow_model": 0.0,
"use_snow_weather_file": 1,
"snow_array": [0],
"use_wf_albedo": 1.0,
"use_spatial_albedos": 0.0,
"albedo": [
Expand Down
2 changes: 2 additions & 0 deletions test/input_json/solesca/test_flush_mount_racking.json
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Expand Up @@ -38,6 +38,8 @@
"transformer_no_load_loss": 0.5,
"transformer_load_loss": 0.8,
"en_snow_model": 0.0,
"use_snow_weather_file": 1,
"snow_array": [0],
"use_wf_albedo": 0.0,
"use_spatial_albedos": 0.0,
"albedo": [
Expand Down
2 changes: 2 additions & 0 deletions test/shared_test/lib_battery_dispatch_pvsmoothing_fom_test.cpp
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Expand Up @@ -58,6 +58,8 @@ TEST_F(PVSmoothing_lib_battery_dispatch, PV_Phoenix_all_on) {
nfc1 = sprintf(file_path, "%s/test/input_cases/general_data/phoenix_az_33.450495_-111.983688_psmv3_60_tmy_1mInterpolated.csv", SSCDIR);
ssc_data_set_string(dat, "solar_resource_file", file_path);



// Run with fixed output
int errors = run_module(dat, "pvsamv1");
// minimize memory usage for Travis
Expand Down
57 changes: 57 additions & 0 deletions test/ssc_test/cmod_pvsamv1_test.cpp
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Expand Up @@ -1044,6 +1044,63 @@ TEST_F(CMPvsamv1PowerIntegration_cmod_pvsamv1, SnowModel)

}


/// Test PVSAMv1 with Snow Model enabled and set to 1-axis Tracking
TEST_F(CMPvsamv1PowerIntegration_cmod_pvsamv1, UserArraySnowModel)
{


std::map<std::string, double> pairs;

pairs["en_snow_model"] = 1;
pairs["subarray1_track_mode"] = 1;

// initial sim to get output snow data;
int pvsam_errors = modify_ssc_data_and_run_module(data, "pvsamv1", pairs);
EXPECT_FALSE(pvsam_errors);
ssc_number_t annual_energy;
ssc_data_get_number(data, "annual_energy", &annual_energy);
EXPECT_NEAR(annual_energy, 11395, m_error_tolerance_hi) << "Annual energy.";

// pull the wf snow data and put it into an array
int l = 8760;
ssc_number_t* snowdepth = ssc_data_get_array(data, "snowdepth", &l);
ssc_data_set_array(data, "snow_array", snowdepth, 8760);
// Use the snow data from the snow depth array
pairs["use_snow_weather_file"] = 0;
pvsam_errors = modify_ssc_data_and_run_module(data, "pvsamv1", pairs);
EXPECT_FALSE(pvsam_errors);
ssc_data_get_number(data, "annual_energy", &annual_energy);
EXPECT_NEAR(annual_energy, 11395, m_error_tolerance_hi) << "Annual energy.";

// Check handling of upsampled data
std::vector<ssc_number_t> upsampled;
upsampled.reserve(8760 * 2);
for (size_t i = 0; i < 8760; i++) {
upsampled.push_back(snowdepth[i]);
upsampled.push_back(snowdepth[i]);
}
ssc_data_set_array(data, "snow_array", upsampled.data(), 8760*2);
pvsam_errors = modify_ssc_data_and_run_module(data, "pvsamv1", pairs);
EXPECT_FALSE(pvsam_errors);
ssc_data_get_number(data, "annual_energy", &annual_energy);
EXPECT_NEAR(annual_energy, 11395, m_error_tolerance_hi) << "Annual energy.";

// Check handling of downsampled data
std::vector<ssc_number_t> downsampled;
downsampled.reserve(8760 / 2);
for (size_t i = 0; i < 8760/2; i++) {
downsampled.push_back(snowdepth[2*i]);
}
ssc_data_set_array(data, "snow_array", downsampled.data(), 8760 / 2);
pvsam_errors = modify_ssc_data_and_run_module(data, "pvsamv1", pairs);
EXPECT_FALSE(pvsam_errors);
ssc_data_get_number(data, "annual_energy", &annual_energy);
EXPECT_NEAR(annual_energy, 11377, m_error_tolerance_hi) << "Annual energy.";


}

TEST_F(CMPvsamv1PowerIntegration_cmod_pvsamv1, SubhourlyClippingCorrectionModel)
{
std::map<std::string, double> pairs;
Expand Down
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