Figure 1. TECO Central Plant Site Plan. (Expansion elements in blue.)
Medical Center space. Being served by a
centralized district energy system also
allows noise and vibration sources such
as large chillers and cooling towers to be
consolidated at the two plant locations.
This is a significant benefit to the Texas
Medical Center as more than one-third of
its building space is dedicated to research
or diagnostic equipment that is highly
sensitive to vibrations.
Coincidentally, an agreement to serve
a major new hospital was reached only
a few weeks before the master plan was
submitted to TECO’s board of directors.
Discussions on serving another major
new hospital are ongoing; most existing
customers are committed to continuing
to use TECO for future hospital and
research facilities.
Plan Recommendations
Completed in February 2007, TECO’s
master plan recommended many additions
to the Central Plant (fig. 1) and distribution system as well as a new chiller facility.
The plan calls for TECO to
install a 45-50 MW gas turbine with
space for a second identical unit;
install a 3-6 MW back-pressure steam
turbine;
install an 8. 75 million-gal, 75,000-
Source: Thermal Energy Corp.
ton-hr chilled-water thermal storage
tank;
add a new East Chiller Plant with
four 8,000-ton electric-drive chillers
and space for six future 8,000-ton
chillers (with extension of the existing perimeter flood wall protecting
the plant, a part of TECO’s detailed
flood plan);
build a 29,000-sq-ft addition to the
Operations Support Facility;
replace an existing 30,000-ton wooden
cooling tower;
expand and upgrade the existing 138
kV substation; and
install additional chilled-water loops
to serve new loads on the west and
south sides.
The plan compared a traditional
plant expansion using electric chillers,
gas boilers and emergency power generation for standby to a CHP system where
TECO could take advantage of generating
its own electricity and recovering the
waste energy. The CHP option prevailed
hands down, with a conservative pro
forma demonstrating a total savings
from CHP alone in excess of $200 million
over the next 15 years, with a possible
best-case scenario savings of $207 million.
In choosing the optimal CHP system
to serve the Texas Medical Center, TECO
and Jacobs Carter Burgess evaluated
three options:
Option 1 – a system sized so that all
the waste heat is used by the campus steam load
Option 2 – a system sized so that all
the waste heat is used by the campus steam load and the two existing
5,000-ton steam turbine-driven
chillers
Option 3 – a system sized so that the
campus cooling load could be met
without the local electric grid
The TECO CHP system will reduce
local emissions of carbon dioxide
the equivalent of removing the
carbon emissions of 51,817 cars
per year.
In addition to lowest life-cycle cost
and lowest customer rates, space limitations, available land and maximizing
reliability were the criteria that resulted
in selection of Option 2 as providing
TECO with the greatest value. A major
benefit of the on-site CHP system is that
TECO will be able to increase chilled-
