Chilled-Water System OptimizationPearl River, N.Y.
Feasibility study award – December 2008 Completed – May 2008
Pfizer (formerly Wyeth) Research Campus consists of three chiller plants with one chiller plant being independent from two other chiller plants. The chilled-water system has the distributed pumping system with smaller plant pumps and larger building pumps. The actual delta T was significantly low compared to the design delta T of 15 degrees F. The chilled- water system operation was very inefficient during low load conditions. The staff was compensating for poor delta T by over-pumping the machines. WM Group was called to review the existing system and find ways to improve delta T and decrease energy consumption.
As part of the feasibility study, WM Group conducted a survey of the site chilled-water generation, distribution and utilization systems. All chilled-water plants had primary-secondary systems with building pumps. WM Group performed hydraulic analysis and determined that the system could be converted to a virtual central variable-volume system by removing building pumps with power over 900 kW. Furthermore WM Group recommended installing the 1,400-ton plate-and-frame heat exchanger to extend the free cooling period. WM Group estimated the annual energy savings of 4,212,893 kWh with estimated annual cost savings of $560,000.
“In an effort to get a handle on how we were running the chilled-water systems and where the opportunities were to optimize these systems, we hired the WM Group to assist us….Through this effort, significant opportunities were revealed to us to do things better and more efficiently….Without exception, everything recommended by WM Group which was implemented provided very significant operational benefit and energy cost savings….We have realized savings in the past 12 months of about $850,000, with a significant portion of this savings directly attributed to the WM Group’s recommendations.”
Bill Geiling, Manager, Plant Engineering and Maintenance