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St. Joseph's Boiler Plant
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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
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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.
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