System Configuration

System configuration defines the physical layout, electrical topology, and operational characteristics of your photovoltaic installation. These parameters directly influence power generation calculations and uncertainty propagation.

Module Parameters

Module parameters define the physical and electrical characteristics of individual photovoltaic modules.

Physical Dimensions

Module Length

Default: 2.0 m
Units: Meters
Usage: View factor calculations for bifacial systems and shading analysis
Impact: Affects row spacing optimization and ground coverage ratio

Module Width

Default: 1.0 m
Units: Meters
Usage: Combined with length to determine module area
Calculation: Area = Length × Width (used for power density calculations)

Height Above Ground

Default: 1.5 m
Units: Meters
Range: ≥ 0 m
Usage: Ground reflection calculations and thermal modeling
Impact: Higher mounting improves air circulation and bifacial gain

Electrical Characteristics

Power Rating at STC

Default: 460 W
Units: Watts
Definition: Nameplate power under Standard Test Conditions (1000 W/m², 25°C, AM1.5)
Usage: Baseline for all power calculations and efficiency derivations

Module Efficiency Temperature Coefficient

Default: 0.00295 /K
Units: Per Kelvin
Definition: Fractional power loss per degree temperature rise above 25°C
Range: > 0 (power decreases with temperature)
Typical values: 0.003-0.004 /K for silicon modules

Bifaciality

Default: 1.0
Range: ≥ 0
Definition: Rear-to-front power ratio under identical irradiance conditions
Values: 0.7-0.95 for typical bifacial modules, 0.0 for monofacial
Usage: Scales rear irradiance contribution to total power

Cell-Level Parameters

Cell-to-Cell Mismatch

Default: 0.004
Range: 0 to 1
Definition: Power variation between cells within a module
Impact: Reduces overall module power output
Application: Represents manufacturing variations and aging effects

System Architecture

System architecture defines how modules are connected and arranged within the installation.

String Configuration

Modules per String

Default: 27
Range: > 0
Definition: Number of modules connected in series
Impact: Affects voltage levels and mismatch losses
Considerations: Limited by inverter input voltage range

Strings per Inverter

Default: 1
Range: > 0
Definition: Number of parallel strings connected to each inverter
Usage: Current capacity and power distribution calculations
Design factor: Affects system granularity and performance optimization

Number of Inverters

Default: 1
Range: > 0
Definition: Total inverters in the system
Impact: System redundancy and inverter loading calculations
Scaling: Determines overall system AC capacity

Physical Layout

Row Pitch

Default: 5.6 m
Units: Meters
Range: > 0 m
Definition: Center-to-center distance between module rows
Usage: Shading calculations and land use optimization
Trade-off: Larger pitch reduces shading but increases land requirements

Module Azimuth

Default: 90° (East-facing)
Units: Degrees
Range: 0° to 360°
Reference: 0° = North, 90° = East, 180° = South, 270° = West
Usage: Solar irradiance calculations and optimal orientation analysis
Regional optimization: South-facing (180°) often optimal in Northern Hemisphere

Fallback Module Tilt

Default: 30°
Units: Degrees
Range: -90° to 90°
Definition: Module tilt angle when not specified in weather data
Usage: Fixed installations or when tracking data unavailable
Optimization: Often set to latitude angle for maximum annual irradiance

Tracking Systems

Tracking Type

Default: Fixed (no tracking)
Options: Fixed tilt, Single-axis tracking
Usage: Determines solar tracking calculations
Impact: Tracking systems increase irradiance capture but add complexity

Tilt Limit

Default: 55°
Units: Degrees
Range: -90° to 90°
Definition: Maximum tilt angle for tracking systems
Purpose: Prevents excessive wind loading and structural stress
Application: Only relevant for tracking installations

Optical Settings

Optical settings control how irradiance components are processed and modified for power calculations.

Irradiance Multipliers

Beam Multiplier Front

Default: 1.0
Range: ≥ 0
Definition: Scaling factor for direct irradiance on front surface
Usage: Accounts for optical enhancements or losses
Examples: Anti-reflective coatings, lens systems

Beam Multiplier Rear

Default: 1.0
Range: ≥ 0
Definition: Scaling factor for direct irradiance on rear surface
Application: Bifacial systems only
Impact: Modifies rear-side direct irradiance contribution

Isotropic Multiplier Front

Default: 1.01
Range: ≥ 0
Definition: Scaling factor for diffuse irradiance on front surface
Typical range: 1.0-1.05 for standard installations
Purpose: Accounts for diffuse light collection efficiency

Isotropic Multiplier Rear

Default: 1.0
Range: ≥ 0
Definition: Scaling factor for diffuse irradiance on rear surface
Usage: Bifacial diffuse light collection modeling

Fallback Values

These values are used when corresponding data is not provided in weather files.

Fallback Albedo

Default: 0.2
Range: 0 to 1
Definition: Ground reflectance when not specified in weather data
Typical values: 0.2 (grass), 0.25 (gravel), 0.4 (concrete), 0.8 (snow)

Fallback Soiling Front

Default: 0.02 (2% losses)
Range: 0 to 1
Definition: Front surface soiling losses when not in weather data
Impact: 0.02 = 2% transmission loss, 0.05 = 5% loss
Seasonal variation: May be higher in dusty or arid climates

Fallback Soiling Rear

Default: 0.01 (1% losses)
Range: 0 to 1
Definition: Rear surface soiling losses for bifacial modules
Rationale: Rear surfaces typically accumulate less soiling than front

Fallback Spectral Correction

Default: 1.0
Range: ≥ 0
Definition: Spectral mismatch correction factor
Usage: Accounts for differences between reference and actual solar spectrum
Variation: Location and weather dependent

Advanced Optical Parameters

Extra Irradiance

Default: 1.0
Range: ≥ 0
Definition: Additional irradiance enhancement factor
Applications: Concentrated PV, reflector systems, or site-specific enhancements

Fallback Rear Transmission Factor

Default: 0.0
Range: ≥ 0
Definition: Light transmission through module structure to rear surface
Relevance: Bifacial systems with semi-transparent or perforated mounting

Fallback Rear Structural Shading Factor

Default: 0.0
Range: 0 to 1
Definition: Fraction of rear surface unshaded by mounting structure
Impact: Reduces effective bifacial collection area
Examples: Frame shadows, mounting rail blockage

Electrical Settings

Electrical settings define power conversion efficiency and system-level losses.

Inverter Performance

Inverter Efficiency

Default: 0.98 (98%)
Range: 0 to 1
Definition: DC to AC power conversion efficiency
Variation: May vary with loading conditions and temperature
Typical range: 0.95-0.99 for modern inverters

System Losses

Inverter Wiring Loss

Default: 0.0 (0%)
Range: 0 to 1
Definition: AC side wiring and connection losses
Components: AC cables, combiner boxes, transformers
Typical values: 0.01-0.03 depending on system size

String Wiring Loss

Default: 0.01 (1%)
Range: 0 to 1
Definition: DC wiring losses within strings
Components: MC4 connectors, DC cables, fuses
Distance dependent: Longer cable runs increase losses

Max Power Tracking Loss

Default: 0.0 (0%)
Range: 0 to 1
Definition: MPPT algorithm efficiency losses
Modern inverters: Typically < 0.005 (0.5%)
Conditions: May increase under rapidly changing conditions

Component Mismatch

Module-to-Module Mismatch

Default: 0.01 (1%)
Range: 0 to 1
Definition: Power variations between modules in same string
Sources: Manufacturing tolerances, aging differences, soiling variations
Impact: Limits string performance to weakest module

String-to-String Mismatch

Default: 0.0 (0%)
Range: 0 to 1
Definition: Power variations between parallel strings
Causes: Shading differences, module variations, wiring differences
Mitigation: Power optimizers, string monitoring

Inverter-to-Inverter Mismatch

Default: 0.0 (0%)
Range: 0 to 1
Definition: Performance variations between inverters
Relevance: Multi-inverter systems only
Sources: Manufacturing differences, environmental conditions

Thermal Settings

Thermal parameters control module operating temperature calculations, which directly affect power output.

Heat Transfer Coefficients

Uc (Convective Heat Transfer)

Default: 25.0 W/m²K
Units: Watts per square meter per Kelvin
Range: ≥ 0
Definition: Base convective heat transfer coefficient
Usage: Module temperature rise calculations above ambient

Uv (Wind-Dependent Heat Transfer)

Default: 1.2 W/m³Ks
Units: Watts per cubic meter per Kelvin per second
Range: ≥ 0
Definition: Wind speed dependent heat transfer coefficient
Formula: Total U-value = Uc + Uv × wind_speed
Impact: Higher wind speeds improve module cooling

Alpha (Solar Absorptance)

Default: 0.9
Range: ≥ 0
Definition: Fraction of incident solar energy absorbed by module
Typical range: 0.85-0.95 for standard modules
Usage: Determines solar heating component of module temperature

Operational Settings

Operational parameters account for real-world performance factors and system availability.

Performance Factors

DC Health

Default: 1.0 (100%)
Range: 0 to 1
Definition: Overall DC system health factor
Applications: Accounts for gradual performance degradation, component aging
Monitoring: Can be updated based on system performance data

Availability

Default: 0.99 (99%)
Range: 0 to 1
Definition: Fraction of time system is operational
Includes: Maintenance downtime, grid outages, equipment failures
Industry typical: 0.97-0.995 depending on system design and maintenance

Curtailment

Default: 0.0 (0%)
Range: 0 to 1
Definition: Fraction of potential power lost to curtailment
Causes: Grid constraints, power purchase agreement limits, frequency regulation
Variability: May be time-of-day or seasonally dependent

Yield Modifier

Default: 1.0
Range: ≥ 0
Definition: Overall yield adjustment factor
Usage: Site-specific corrections, performance guarantees
Applications: Accounts for factors not captured in other parameters

Undulating Ground

Default: 1.0
Range: ≥ 0
Definition: Ground topology correction factor
Purpose: Accounts for non-flat terrain effects on irradiance
Relevance: Hilly or sloped installation sites

Degradation

Annual Degradation Rate

Default: 0.0 (0% per year)
Range: 0 to 1
Definition: Annual fractional power loss due to aging
Typical values: 0.005-0.008 (0.5-0.8% per year) for silicon modules
Application: Applied cumulatively over analysis period