DA-76-07-2 -- Operating Experience with Return Temperature Control of Chilled Water PDF

The Purdue University central chilled water system serves a campus of some 647 acres. The ,chiller plant has an installed cooling capacity of 13,200 tons and is connected to 44 differentbuildings by approximately 35,500 ft. (6.7 miles) of underground piping. Within the 44 buildings,the central cooling system serves 260 major air conditioning systems and 2,775 fan coilor induction units. The cooling equipment installed in the 44 buildings represents totalinstalled load of 12,900 tons.

The authors believed that if they could conceive a control system that would allow terminal units to utilizethe full temperature rise of the chilled water over the entire load range, and provideadequate space cooling, they would greatly increase the capacity of the system. Also, the controlsystem had to be applicable to the existing systems. One of the avenues pursued was return watertemperature control which is discussed this paper.