By J. Michael Pearson, P.E., Senior Electrical Engineer, DLR
Group, Phoenix In this era of green architecture, there is one
sustainability tool at our disposal that has been most
underutilized—the technology of power-factor correction. In
fact, the U.S. Green Building Council would do well to include
power-factor correction as one of its credits for its Leadership
in Environmental and Energy Design certification program. We
engineers know power factor (PF) mainly as a mathematical
expression of the efficiency with which electrical energy is
used. More specifically, it is the ratio of "apparent" to "real"
power, or even more precisely, the cosine of the angle between
these two electrical vectors. And while this famous power
triangle is among the first lessons taught in engineering
school, its significance too often becomes overshadowed when one
gets down to the business of designing building systems. There
are several reasons for this, and they have, largely, to do with
economic realities. First and foremost,