Solarius-PV Case Study: Designing a 50 kW Commercial Solar System

Location: Assumed mid-latitude commercial rooftop (e.g., 40°N)
System size: 50 kW (AC-rated)
Roof type: Flat with tilt frames (assumed 10° tilt)
Mounting: South-facing arrays with 2 rows, string inverter layout
Primary goals: Maximize annual energy yield, meet structural/spacing constraints, optimize stringing for shading and mismatch

Create new project: Enter site coordinates (40°N, longitude assumed), climate file selection (typical meteorological year, TMY3 or local) and timezone.
Model geometry: Define flat roof area, usable surface, obstruction heights (parapet, HVAC). Set panel tilt to 10° and azimuth 180° (south).
Select components: Choose a commercial PV module (e.g., 400 W mono PERC) and a compatible string inverter (e.g., 50 kW central or two 25 kW string inverters). Enter module and inverter datasheets or pick from library.
Electrical configuration: Configure string lengths, number of strings, DC/AC ratio (~1.2), MPPT settings, and cable runs. Use Solarius-PV automatic stringing or manual layout to meet Vmp/Voc limits and inverter MPP ranges.
Shading and losses: Model near-field shading (rows, parapet) and far-field shading if needed. Input system losses: soiling (~2%), module mismatch (~1%), wiring (~2%), temperature coefficient and thermal losses per datasheet, and inverter efficiency.
Structural checks: Enter module weight, wind and snow loads per local code; run basic structural verifications available in Solarius-PV (or export to structural tool if needed).
Simulation run: Run annual production simulation with hourly resolution, review monthly and annual energy, and check performance ratio (PR).

Modules: 400 W, STC; 125 modules (50,000 W / 400 W = 125)
Array DC size: 50 kW DC (DC/AC 1.0) or 60 kW DC for DC/AC 1.2
Strings: 25 strings of 5 modules (example) — adjust to inverter limits
Estimated losses total: ~14% (soiling, mismatch, temp, wiring, etc.)
Expected annual production: ~60,000–70,000 kWh/year (assumes 4.8–5.6 kWh/kW/day average depending on location)
Performance ratio: ~0.75–0.82

DC/AC ratio: Higher ratio increases energy capture during low-irradiance but may clip in peak sun—choose 1.1–1.3 based on inverter clipping vs. energy gain analysis.
Stringing: Balance between fewer long strings (less combiner complexity) and meeting inverter V/I limits; consider mismatch from partial shading.
Inverter choice: Central inverter simplifies O&M for uniform arrays; string inverters or microinverters give better shading tolerance and monitoring granularity.
Tilt/azimuth: Small tilt on flat roof reduces soiling and wind loads; optimized tilt may marginally increase yield but increase structural complexity.

Single-line electrical diagram and stringing plan
Module layout and roof plan with shading visualization
Energy yield report (hourly/monthly/annual) and PR
Loss breakdown and sensitivity analysis (e.g., different DC/AC ratios, tilt angles)
Exportable reports for permitting and client proposals

Use site-specific irradiance (TMY or satellite) for best accuracy.
Run sensitivity cases for DC/AC ratios and inverter selection.
Validate shading inputs on-site (measure parapet/obstruction heights).
Keep string lengths within inverter voltage window at coldest expected temperature.

Date: February 6, 2026

Comments