System types and layout overview

SunSolve Yield allows you to simulate three distinct types of PV system configurations, each with its own set of structural components and layout characteristics.

Available system types

There are currently three types of system that can be defined:

1. Fixed - modules have a single tilt angle and azimuth; the structure is comprised of posts, rafters and purlins.

2. Single axis tracker - modules will rotate about an axis point to follow the sun; the structure includes posts, rails and torque tubes.

3. Waves - modules have a single tilt angle and are arranged in pairs that face each other; the structure includes ballast blocks, rails and joints.

All system types support custom objects for representing additional structures or obstructions. Custom objects can be basic geometric shapes (box, sphere, cylinder) or complex shapes loaded from STL files generated with CAD software. They can be attached to the fixed part of the scene, the rotating part (for trackers), or to individual modules.

System-specific documentation

• Fixed System Layout - Details on fixed-tilt systems with purlins, rafters, and posts
• Waves System Layout - Information on wave configurations with ballasts, rails, and joints
• Single-Axis Tracker Layout - Guidance on tracking systems with torque tubes, clamps, and posts

Key concepts

Unit system

All three system types use the concept of a unit system - a representative section of the PV array that is repeated infinitely in all directions. By simulating a unit system rather than an entire array, SunSolve can accurately model the behavior of modules in the interior of large installations while minimizing computational requirements.

The unit system serves as the optical simulation domain for ray tracing. SunSolve performs wavelength-dependent ray tracing exclusively within the unit system boundaries, calculating light absorption in each cell based on the system structure, module arrangement, and ground properties defined there. The ray-traced optical results are then used by the electrical model:

• Module DC simulations: Electrical calculations use the ray-traced unit-system results directly
• String DC and Array AC simulations: Unit-system results are scaled to represent the full electrical array by multiplying by the ratio of total modules to unit-system modules

This approach allows SunSolve to accurately model optical effects like inter-row shading and structure shadowing in a representative unit system, then scale those results to calculate energy yields for much larger field layouts.

Technical constraints

The number of modules you can include in the unit system is limited by the computational requirements of ray tracing. SunSolve enforces maximum ray counts to ensure simulations complete in reasonable time with available system resources.

The actual limit depends on:

• Module type - Whether you’re using a simple module (simplified optics) or a complex module (full optical detail)
• Fidelity level - The optical fidelity setting (0.5×, 1×, 2×, 4×, 8×) that scales the number of rays traced per module
• Module count - More modules require more rays

The system calculates the maximum allowable rays as: moduleCount × 2,000,000 × fidelityMultiplier

Hard limits:

• Complex modules: 30 million rays maximum
• Simple modules: 250 million rays maximum

For a typical 144-cell module at different fidelity levels, the approximate maximum unit system module counts are:

Simple modules (simplified optics):

Fidelity Level	Max Modules
0.5×	249
1×	124
2×	61
4×	30
8×	14

Complex modules (full optical detail):

Fidelity Level	Max Modules
0.5×	29
1×	14
2×	6
4×	2
8×	0

If you exceed these limits, SunSolve will display the error: “Too many cells or modules for the unit system. Please consider ray tracing a smaller section of the system or selecting a simple module or using a lower fidelity level.”

Solutions if you encounter this limit:

1. Reduce the unit system size - Include fewer modules in your unit system (the optical results will still be scaled to your full array for String/Array simulations)
2. Use simple modules - Switch to simple module mode which allows much larger unit systems at the cost of simplified optical modeling
3. Lower fidelity - Reduce the fidelity level setting, though this will decrease the number of rays traced per module (see stochastic error for accuracy implications)

Dimension definition methods

Fixed and Single-axis Tracker systems support two dimension definition methods (XY Axis and Landscape/Portrait), while Waves systems use their own specialized approach based on peak and trough separations.

For detailed information about the dimension definition methods, see System dimensions: XY axis and landscape/portrait.

Select the system type that matches your installation, then refer to the corresponding detailed documentation page for configuration guidance.