High-Efficiency Central Chiller Plant for Medical Center

This project called for a new central chiller plant for a major NYC medical center. Large horizontal split case pumps, a pre-fabricated secondary chilled water VFD package, and the plate and frame heat exchanger (for free-cooling) were specified and provided by G.A. Fleet. SCHW VFD controls include advanced logic for sequencing 300 HP pumps with the highest wire-to-water efficiency.

 

Horizontal split case pumps for condenser water. These pumps were selected specifically for their extremely low NPSHR (under 14 ft), since the cooling tower was located only one floor above the pump level.



Installation of horizontal split case pump showing proper installation of a single pressure gage with isolation valves for suction and discharge connections. This installation is recommended to eliminate the loss of calibration over time when using separate gauges for reading suction and discharge pressure.



This pre-fabricated, pre-engineered Secondary Chilled Water VFD and control system operates the (3) 300 HP SCHW pumps. Each VFD includes soft-start bypass. The control logic operates the SCHW system at the lowest possible energy consumption using wire-to-water efficiency analysis. H-O-A switches are provided for simple operator control in the event of electronic control failure.



The plate and frame heat exchanger is utilized for free cooling operation. In this cooling mode the refrigeration and dehumidification requirements of the medical center are met without mechanical cooling (chillers) by rejecting the CHW heat gain through the cooling tower. Plate type heat exchangers are ideal for this application due to the large surface area in a small footprint, allowing a close approach temperature between the hot and cold circuits.