Quick Answer
Reactive loads, such as motors and fluorescent lighting, consume real power but also create a lagging power factor due to inductive characteristics. Resistive loads, like incandescent lighting and heating elements, have a power factor of one and do not create a lagging or leading power factor. This distinction is crucial when calculating solar load requirements.
Understanding Reactive Loads
Reactive loads are a critical consideration when calculating solar load requirements. A 10 kilowatt (kW) motor with a power factor of 0.8 lagging means it consumes 12.5 kVA (10 kW / 0.8 power factor). To calculate the required solar panel size, you must consider the total kVA of reactive loads, as well as resistive loads. A general rule of thumb is to use a 1.25 to 1.5 multiplier for the total kVA of reactive loads to account for system losses and inverter efficiency.
Calculating Resistive Loads
Resistive loads typically have a power factor of one, meaning the kW rating is equal to the kVA rating. When calculating solar load requirements, it’s essential to consider the total kW of resistive loads, which can be found on the appliance’s nameplate or calculated based on usage patterns. For example, a 4 kW incandescent lighting system has a total kVA requirement of 4 kVA, as the power factor is one.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.