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HST software interfaces with the pvsamv1 module within the SAM SDK for all energy simulations. The following table defines the specific SAM input variables which are set by HST software:

 

SAM VariableValueDescription
6par_aiscUser Defined (within User Defined Module) Open circuit voltage temperature coefficient
6par_areaUser Defined (within User Defined Module) Module area
6par_bifacial_ground_clearance_heightUser Defined (within User Defined Module) Ground Clearance Height of Rack (used for bifacial model)
6par_bifacial_ground_transmission factorUser Defined (within User Defined Module)Percentage of Front-side module area allowing passage of light, including gaps between modules.
6par_bifacialityUser Defined (within User Defined Module) Ratio of backside cell efficiency to frontside cell efficiency
6par_bvocUser Defined (within User Defined Module) Short circuit current temperature coefficient
6par_celltechUser Defined (within User Defined Module) Solar cell technology type
6par_gpmpUser Defined (within User Defined Module)Maximum power point temperature coefficient
6par_impUser Defined (within User Defined Module) Maximum Power Point Current
6par_iscUser Defined (within User Defined Module) Maximum Short Circuit Current
6par_is_bifacialUser Defined (within User Defined Module) Toggle to specify if module is bifacial or not
6par_mountingFixed = One Story Building Height or LessArray mounting height
6par_nserUser Defined (within User Defined Module)Number of Cells in Series
6par_standoffFixed = Ground or Rack Mounted Standoff mode
6par_tnoctUser Defined (within User Defined Module) Nominal operating cell temperature
6par_vmpUser Defined (within User Defined Module)Maximum power point voltage
6par_vocUser Defined (within User Defined Module)Maximum Open Circuit Voltage
acwiring_lossSet to 0All AC modeling simulated external to SAM simulation
ac_transmission_lossSet to 0All AC modeling simulated external to SAM simulation
adjust:constantSet to 0All AC modeling simulated external to SAM simulation
albedoDefault = 0.2Ground Albedo used only if this data is not included in hourly weather file 
cec_a_refFixed (from CEC Module Database per User Selection of Module)Nonideality factor a
cec_adjustFixed (from CEC Module Database per User Selection of Module)Temperature coefficient adjustment
cec_alpha_scFixed (from CEC Module Database per User Selection of Module) Short circuit current temperature coefficient
cec_areaFixed (from CEC Module Database per User Selection of Module) Module area
cec_array_colsFixed = 10Columns of modules in array. Note: This parameter is not used in the energy model since cec_heat_transfer is set to use modue dimensions instead of Array dimensions
cec_array_rowsFixed = 1Rows of modules in array. Note: This parameter is not used in the energy model since cec_heat_transfer is set to use modue dimensions instead of Array dimensions
 cec_backside_tempFixed = 20Module backside temperature. Note: This parameter is not used in the energy model since cec_mounting_config is set to Rack Mounted
 cec_beta_ocFixed (from CEC Module Database per User Selection of Module)Open circuit voltage temperature coefficient
cec_bifacial_ground_clearance_heightUser Defined (within User Defined Module) Ground Clearance Height of Rack (used for bifacial model)
cec_bifacial_ground_transmission factorUser Defined (within User Defined Module)Percentage of Front-side module area allowing passage of light, including gaps between modules.
cec_bifacialityUser Defined (within User Defined Module) Ratio of backside cell efficiency to frontside cell efficiency
 cec_gamma_rFixed (from CEC Module Database per User Selection of Module) Maximum power point temperature coefficient
 cec_gap_spacingFixed = 0.05Module Gap Spacing Note: This parameter is not used in the energy model since cec_mounting_config is set to Rack Mounted
 cec_heat_transferFixed = Module DimensionsHeat transfer dimensions
 cec_heightFixed = One Story building Height or Lower Array mounting height
cec_is_bifacialUser Defined (within User Defined Module) Toggle to specify if module is bifacial or not
 cec_i_l_refFixed (from CEC Module Database per User Selection of Module) Light current
 cec_i_mp_refFixed (from CEC Module Database per User Selection of Module) Maximum power point current
 cec_i_o_refFixed (from CEC Module Database per User Selection of Module) Saturation current
 cec_i_sc_refFixed (from CEC Module Database per User Selection of Module)Short circuit current
 cec_module_lengthUser DefinedModule Length
 cec_module_widthUser DefinedModule Width
 cec_mounting_configFixed = Rack MountedMounting configuration
 cec_mounting_orientationFixed = Structures Do Not Impede Flow UnderneathMounting structure orientation
 cec_n_sFixed (from CEC Module Database per User Selection of Module) Number of cells in series
 cec_r_sFixed (from CEC Module Database per User Selection of Module) Series resistance
 cec_r_sh_refFixed (from CEC Module Database per User Selection of Module) Shunt resistance
 cec_standoffFixed = Ground or Rack Mounted Standoff mode
 cec_t_noctFixed (from CEC Module Database per User Selection of Module) Nominal operating cell temperature
 cec_temp_corr_modeFixed = Heat Transfer MethodCell temperature model selection
 cec_v_mp_refFixed (from CEC Module Database per User Selection of Module) Maximum power point voltage
 cec_v_oc_refFixed (from CEC Module Database per User Selection of Module) Open circuit voltage
 dc_adjust:constantUser Defined = Non-Ohmic DC Loss Input DC Constant loss adjustment
 dcoptimizer_lossFixed = 0 DC power optimizer loss
 inv_ds_effUser Defined (within User Defined Inverter) Weighted or Peak or Nominal Efficiency
 inv_ds_pacoUser Defined (within User Defined Inverter) AC maximum power rating
 inv_ds_pntUser Defined (within User Defined Inverter) AC power consumed by inverter at night
 inv_ds_psoUser Defined (within User Defined Inverter) DC power required to enable the inversion process
 inv_ds_vdcmaxUser Defined (within User Defined Inverter) Maximum DC input operating voltage
 inv_ds_vdcoUser Defined (within User Defined Inverter) DC input voltage for the rated AC power rating
 inv_snl_c0Fixed (from CEC Inverter Database per User Selection of Inverter) Curvature between AC power and DC power at ref
 inv_snl_c1Fixed (from CEC Inverter Database per User Selection of Inverter) Coefficient of Pdco variation with DC input voltage
 inv_snl_c2Fixed (from CEC Inverter Database per User Selection of Inverter) Coefficient of Pso variation with DC input voltage
 inv_snl_c3Fixed (from CEC Inverter Database per User Selection of Inverter) Coefficient of Co variation with DC input voltage
 inv_snl_pacoFixed (from CEC Inverter Database per User Selection of Inverter) AC maximum power rating
 inv_snl_pdcoFixed (from CEC Inverter Database per User Selection of Inverter) DC input power at which AC power rating is achieved
 inv_snl_pntFixed (from CEC Inverter Database per User Selection of Inverter) AC power consumed by inverter at night
 inv_snl_psoFixed (from CEC Inverter Database per User Selection of Inverter) DC power required to enable the inversion process
 inv_snl_vdcmaxFixed (from CEC Inverter Database per User Selection of Inverter) Maximum DC input operating voltage
 inv_snl_vdcoFixed (from CEC Inverter Database per User Selection of Inverter) DC input voltage for the rated AC power rating
 inverter_countHST Calculated Number of inverters
 inverter_modelFixed (CEC Model when CEC Inverter Selected or Datasheet Model when User Defined Inverter Data Entered) Inverter model specifier
 irrad_modeUser Defined Irradiance input translation mode
 module_modelFixed (CEC Model when CEC Module Selected or 6 Parameter Model when User Defined Module Data Entered) Photovoltaic module model specifier
 modules_per_stringHST Calculated Modules per string
 mppt_hi_inverterUser Defined (if User Defined Inverter) / Fixed (if CEC Inverter) Maximum inverter MPPT voltage window
 mppt_low_inverterUser Defined (if User Defined Inverter) / Fixed (if CEC Inverter) Minimum inverter MPPT voltage window
 sky_modelFixed = Perez Diffuse sky model
 solar_resource_fileUser Defined Weather file in TMY2, TMY3
 strings_in_parallelHST Calculated String in parallel
 subarray1_azimuthHST Calculated (if Optimized over Azimuth) Otherwise User Defined Sub-array 1 Azimuth
 subarray1_backtrackUser Defined Sub-array 1 Backtracking enabled
 subarray1_dcwiring_lossHST Calculated = DC String + DC Feeder Wiring Losses Sub-array 1 DC wiring loss
 subarray1_diodeconn_lossFixed = 0 Sub-array 1 DC diodes and connections loss
 subarray1_gcrHST Calculated (if Optimized over Row Spacing) Otherwise User Defined Sub-array 1 Ground coverage ratio
 subarray1_mismatch_lossFixed = 0 Sub-array 1 DC mismatch loss
 subarray1_mod_orientUser Defined (Landscape or Portrait)Sub-array 1 Module orientation for self-shading
 subarray1_nameplate_lossFixed = 0Sub-array 1 DC nameplate loss
 subarray1_nmodxHST Calculated Sub-array 1 no. of modules along bottom for self-shading
 subarray1_nmodyUser Defined = Number of Modules Up per RackSub-array 1 no. of modules along side for self-shading
 subarray1_rotlimUser Defined Sub-array 1 Tracker rotation limit
 subarray1_shade_modeFixed = Non-Linear (if Crystaline) or Linear (if Thin Film) Sub-array 1 shading mode (fixed tilt or 1x tracking)
 subarray1_soilingUser Defined (Annual or Monthly) Sub-array 1 Monthly soiling loss
 subarray1_tiltHST Calculated (if Optimized over Tilt) Otherwise User Defined Sub-array 1 Tilt
 subarray1_track_modeUser Defined (Fixed-Tilt or Tracking) Sub-array 1 Tracking mode
 subarray1_tracking_lossFixed = 0 Sub-array 1 DC tracking error loss
 subarray2_enableFixed = Disabled Sub-array 2 Enable
 subarray3_enableFixed = Disabled Sub-array 3 Enable
 subarray4_enableFixed = Disabled Sub-array 4 Enable
 system_capacityHST Calculated = DC Nameplate Rating DC Nameplate capacity
 system_use_lifetime_outputUser Defined (either 1st year or lifetime simulation) PV lifetime simulation
 transformer_load_lossSet to 0All AC modeling simulated external to SAM simulation
 transformer_no_load_lossSet to 0All AC modeling simulated external to SAM simulation
use_wf_albedoSet to YesUses hourly Ground Albedo if included in weather file 
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SAM IMPLEMENTATION