Diversity factor

${\displaystyle f_{\text{Diversity}}=\frac{\sum _{i=1}^n{\text{Individual peak load}}_i}{\sum _{i=1}^n\text{Max}({\text{Aggregated load}}_i)}}$

The diversity factor is always greater than 1. The aggregate load ${\displaystyle \left(\sum _{i=1}^n{\text{Aggregated load}}_i\right)}$ is time dependent as well as being dependent upon equipment characteristics. The diversity factor recognizes that the whole load does not equal the sum of its parts due to this time interdependence or "diversity." For example, one might have ten air conditioning units that are 20 tons each at a facility with an average full load equivalent operating hours of 2000 hours per year. However, since the units are each thermostatically controlled, it is not known exactly when each unit turns on. If the ten units are substantially larger than the facility's actual peak AC load, then fewer than all ten units will likely come on at once. Thus, even though each unit runs a total of a couple of thousand (2000) hours a year, they do not all come on at the same time to affect the facility's peak load. The diversity factor provides a correction factor to use, resulting in a lower total power load for the ten AC units. If the energy balance done for this facility comes out within reason, but the demand balance shows far too much power for the peak load, then one can use the diversity factor to bring the power into line with the facility's true peak load. The diversity factor does not affect the energy; it only affects the power.

Coincidence factor

The coincidence factor is the reciprocal of the diversity factor. The simultaneity factor may be identical to either the coincidence factor or the diversity factor, depending on the sources of definition; the International Electrotechnical Commission defines the coincidence and simultaneity factors identically, with the diversity factor being their reciprocal. Since the only change in definition is to take the inverse, all one needs to know is whether the factor is greater than or less than one.