Most chillers are designed for peak load and then
operate at loads less than the peak most of the time.
Many chiller manufacturers provide data that identifies
a chiller’s part-load performance as an aid to evaluating
energy costs. Ideally a chiller operates at a desired temperature
difference (typically 45-55 degrees F; 25-30 degrees
C) at a given flow rate to meet a given load. As the
load requirement increases or decreases, the chiller will
load or unload to meet the need. A reset schedule that
allows the chilled water temperature to be adjusted to
meet thermal building loads based on enthalpy provides
an ideal method of reducing energy consumption.