Bill makes a good point about taking advantage of the lower temperature
of the ice system. I worked on a project that had an ice storage system
that took advantage of the colder temperature. We made the chilled water
supply temperature 38F and return temperature 62F (DeltaT=24F). The
pumping power saved was pretty significant, since the chilled water had
to be pumped underground more than 1200 feet from the Chiller Plant to
the main building. The lower chilled water temperature allowed me to use
lower supply air temperature at the air handlers, which allowed me to
select smaller air handlers (due to lower cfm), which allowed me to
actually fit the air handlers into the allotted space! So there are more
benefits than just energy cost benefits...if you take advantage of the
opportunities.

Sincerely,

Keith Swartz, PE, LEED(r) AP