St. Joseph's Hospital and Medical Center
Phoenix, AZ

Syska Hennessy Group provides extensive infrastructure consulting to Catholic Healthcare West's largest facility - the 1.3M sq. ft. campus of St. Joseph's Hospital in Phoenix, Arizona. Just five years ago the campus on 3rd Avenue and Thomas had a much different look. The hospital had two chiller plants. One of these chiller plants was co-located in the center of the main hospital building with the high-pressure steam plant. The hospital administrators were again in a growth mode and saw the central real estate taken-up by the old plant as too valuable. This location was also problematic due to the fact that the systems within plant were boxed in by the growth of the medical facility over the years. No expansion of the boiler plant or this internal chiller plant was possible. Also as part of this project an existing utility tunnel needed to be eliminated to allow for the growth of the medical facility. This tunnel carried all of the main medical gas systems to the hospital.

Syska Hennessy Group was acquired to first be the campus utilities master plan engineer as well as to produce a central plant study. Our concept was to move all of the chillers to the north plant, create a new north boiler plant and completely rework all of the piping systems. The study compared co-generation and a couple different hybrid plants to an all-electric plant. Through our analysis of the existing conditions of the facility we found that the hydraulics of the chilled water system were such that several large portions of the main hospital were being starved of capacity during peak season.


St. Joseph Chiller

The result of the owner's review of the study was a hybrid plant. 3250 ton electric and 2500 tons gas-fired absorption, as well as a new 30,000 #/hr, 125 psig steam plant. Our redesign of the plant occurred in phases, as did all of the cross connections within the main hospital. To keep them in business, all of the new capacity had to installed and operational prior to tying into the hospital and removing the old plant. The piping within the existing plant could not support the new total capacity, so all new piping and pumping systems were installed in phases. This allowed us to bring the new gas-fired portion of the plant on-line to pickup the load of the hospital, so the existing electric portion of the plant could be retrofitted to work in harmony with the new system. All of the hospital's chilled water, steam and medical gas systems were tied over to the new equipment with NO Downtime. Internal to the hospital several variable speed booster pumping stations were installed which resolved the hydraulic problems in an energy saving manner with variable frequency drives and return water maximizing logic.