Solar Array Sizing: How to Calculate for Peak Summer Use?

Understanding Peak Summer Load

To calculate solar array sizing for peak summer use, you must first determine the highest energy demand during this period. This involves analyzing your energy consumption patterns, usually expressed in kilowatt-hours (kWh), and identifying the most energy-intensive appliances and systems. For residential applications, consider factors like air conditioning, pool pumps, and refrigeration units.

Calculating Peak Power Demand

Using data from your past energy bills or by analyzing your energy usage patterns, identify the peak power demand in kilowatts (kW). This can be found by dividing the peak energy demand (in kWh) by the number of hours it occurs. For example, if your peak demand is 10 kWh and it occurs in 1 hour, the peak power demand is 10 kWh / 1 hour = 10 kW. Then, consider the system losses, including inverter efficiency and wiring losses, which typically range from 10-20% for well-designed systems.

Determining System Size

To calculate the required system size, consider the peak power demand and the system’s efficiency. A general rule of thumb is to oversize the system by 10-20% to account for system losses and ensure a reliable supply during peak periods. For example, if the peak power demand is 10 kW, the system size would be 11-12 kW to account for system losses. Additionally, consider the solar irradiance in your area during peak summer months, which can affect the system’s performance. A good rule of thumb is to use the 75% DC system efficiency and 80% AC system efficiency.