Introduction to Solar PV Systems

Introduction to Solar Photovoltaic (PV) Systems
Key concepts, components, and design fundamentals

1. What Is a Solar PV System?

• Definition: A solar photovoltaic (PV) system converts sunlight directly into electricity using semiconductor devices (solar cells) that exhibit the photovoltaic effect.
• Typical Applications
  • Residential rooftop installations
  • Commercial and industrial rooftop/ground‑mount systems
  • Utility‑scale solar farms
  • Off‑grid power for remote sites, telecom towers, RVs, and marine vessels

2. Core Components & Their Functions

3. Basic System Configurations

1. Grid‑Tied (On‑Grid) System

   • No storage; power exported to grid when generation exceeds load.
   • Requires anti‑islanding protection.

2. Hybrid System

   • Grid‑tied + battery backup.
   • Provides backup during outages and can perform load‑shifting.

3. Off‑Grid System

   • No grid connection; relies on batteries + possibly a generator.
   • Must be sized for worst‑case load and autonomy days.

4. Design Fundamentals

4.1 Sizing the PV Array

1. Determine Energy Demand

   • Calculate average daily consumption (kWh/day) from utility bills or load inventory.

2. Account for System Losses

   • Typical derating factor: 0.75 – 0.85 (covers inverter efficiency, wiring, temperature, shading).

3. Compute Required DC Capacity

[ \text{Required DC (kW)} = \frac{\text{Daily Energy (kWh)}}{\text{Peak Sun Hours (PSH)} \times \text{Derating Factor}} ]

• Peak Sun Hours: average solar irradiance (kW/m²) integrated over a day for the site (e.g., 4.5 h for many U.S. locations).

4. Select Number of Modules

[ \text{Modules} = \frac{\text{