Electrical Load Diversity Factor (DF) is a measure of how much the total electrical load of a commercial building varies from the sum of individual maximum loads. It is used to account for the fact that not all electrical loads in a building operate at their peak simultaneously. A lower diversity factor indicates a more uniform load distribution, while a higher diversity factor suggests that the peak loads of different electrical devices occur at different times.
To calculate the electrical load diversity factor in a commercial building, follow these steps:
Identify individual loads: Make a list of all the major electrical loads in the building, such as lighting, HVAC systems, motors, computers, kitchen equipment, elevators, etc. Note down their respective maximum power ratings (usually in kilowatts, kW) or their demand in kilovolt-amperes (kVA) if it's an AC system.
Determine the maximum coincident load: Find the sum of the maximum power ratings or demands of all individual loads that are likely to operate simultaneously at any given time. This represents the maximum coincident load of the building.
Calculate the total building load: Measure or obtain data on the total electrical load of the building during a specific period, such as a day or a month. This total load can be obtained from the utility bills or through monitoring devices.
Determine the Diversity Factor: The Diversity Factor (DF) is calculated using the formula:
Diversity Factor (DF) = Maximum Coincident Load / Total Building Load
For example, if the maximum coincident load is 200 kW and the total building load is 300 kW, the Diversity Factor would be 200 kW / 300 kW = 0.67.
It's important to note that the Diversity Factor can vary depending on the time of day, day of the week, or even the season. Therefore, it's recommended to analyze load data over an extended period to get a more accurate representation of the building's electrical load diversity.
By considering the Diversity Factor, electrical engineers and designers can properly size the electrical systems, generators, and other infrastructure to handle the maximum expected load without unnecessary over-sizing and cost.