Chilling in Chicago

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Citizens Acquires Water, Wastewater Systems

Olympic-Scale Community Energy

Campus Conference Wrapup

103rd Annual Conference Preview

… and more

District EnergySECOND QUARTER 2012

www.districtenergy.org

The city of Chicago has long been known for its bold

approach to engineering and industry. The world’s

first steel frame skyscraper, the Home Insurance

Building, was built in Chicago in 1885; it helped

launch a revolutionary style of commercial architecture,

known as the Chicago School, that allowed the creation of

tall, slender buildings with a strong and relatively delicate

steel skeleton. Fifteen years later, engineers reversed the flow

of the Chicago River so that it emptied into the Mississippi

River instead of Lake Michigan, thereby alleviating a growing

sanitation problem.

A more recent example of Chicago-style engineering is the

city’s district cooling network. Thermal Chicago Corporation

owns and operates the world’s largest interconnected district

cooling system, serving about 100 buildings and 45 million sq ft

of space in downtown Chicago. The system includes five inter-

connected plants serving the Loop, West Loop, South Loop and

Cover Story

© 2012 International District Energy Association. ALL RIGHTS RESERVED. 12 District Energy / Second Quarter 2012

Hog Butcher for the World,

Tool Maker, Stacker of Wheat,

Player with Railroads and the

Nation’s Freight Handler;

Stormy, husky, brawling,

City of the Big Shoulders.

– From Carl Sandburg’s poem “Chicago,” 1916

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River North areas. Thanks to its proven reliability and multiple

benefits, customers have turned to Thermal Chicago’s district

cooling service as an alternative for both new and replacement

air-conditioning systems. Its mixed customer base includes

commercial facilities, office towers, condominiums, apartment

buildings, theaters, hotels, data centers, retail centers and

schools. Its contract capacity has increased approximately

15 percent since 2004 – and it’s still growing.

System History Chicago’s district cooling system has a brief but intrigu-

ing history. Its origins can be traced back to a landmark inter-

national agreement designed to reverse the thinning of the

stratospheric ozone layer that shields the planet from UV-B

radiation. The Montreal Protocol on Substances that Deplete

the Ozone Layer was negotiated and signed by 24 countries

and the European Economic Community in September 1987.

District Cooling, Chicago-Style: World’s largest interconnected system continues to grow

© 2012 International District Energy Association. ALL RIGHTS RESERVED. District Energy / Second Quarter 2012 13

The Protocol called for the phase-out of ozone-depleting

chemicals including chlorofluorocarbons (CFCs), commonly

used as refrigerants in air-conditioning systems. Many of

Chicago’s commercial buildings were operating chillers that

used such refrigerants and were thus faced with the expensive

prospect of either replacing or refurbishing them. Chicago’s

electric utility, Commonwealth Edison Co. (ComEd), convinced

customers to contract their cooling service from a new district

cooling system that could operate without CFCs.

During the early 1990s, it was not uncommon for regu-

lated utilities like ComEd (now a subsidiary of Exelon Corp.)

to branch out into nonregulated utilities such as thermal

energy systems. ComEd saw such an opportunity in down-

town Chicago and built a district cooling plant in the heart

of the Loop. By 1995 the system had about a dozen custom-

ers, primarily older buildings whose chillers would have soon

required replacement. Over time, the customer base expanded

© 2012 International District Energy Association. ALL RIGHTS RESERVED.

to include new construction as well.

Additional plants were gradually added

to satisfy the increased demand, and by

2002 the system had grown to include

five interconnected plants throughout

the downtown area.

Even as the district cooling network

was being expanded, its ownership was

going through several transitions. In

the late 1990s ComEd went through

a merger, and its parent company

became Unicom, which then merged

with Pepco to become Exelon, the larg-

est owner-operator of nuclear power

plants in the U.S. Exelon shed most of

its nonregulated businesses around

2004, which is when Thermal Chicago

was sold to Macquarie Infrastructure

Co., its current owner. After this dives-

titure, Macquarie retained ownership

of the Chicago cooling system along

with two other properties from the

Exelon portfolio: 100 percent of a large

municipal heating and cooling opera-

tion outside downtown Chicago and

75 percent of the heating, cooling and

emergency power systems at the Planet

Hollywood complex in Las Vegas. This

complex includes the Planet Hollywood

Hotel and Casino, a shopping mall, a

performing arts theater, and a condo/

time-share tower (formerly known as

Westgate). These installations are cur-

rently operated by Thermal Chicago.

Finding Opportunities in Unlikely Places Finding vacant land to build cooling

plants in Chicago’s urban core was not

an easy proposition, but that challenge

inspired a number of creative solutions

that ultimately proved effective. The

first plant, P1, was located at State and

Adams and was designed to include first-

floor retail to comply with area zoning.

Its exterior facade gives few clues as to

what’s inside: four 5,000-ton chillers, 66

ice tanks with a capacity of 66,000 ton-

hr, three large cooling towers, and relat-

ed pumps, valves and other equipment.

The next plant, P2, was built in

1996 at the corner of Franklin and Van

Buren. It is the only plant designed

exclusively as a cooling facility, and,

unlike the others, it does not share the

property with any other users. P2 con-

tains one of the world’s largest ice tanks,

with a capacity of 2 million gal. It can

deliver 125,000 ton-hr of cooling to the

system. The plant has won several archi-

tectural awards and is featured on the

Chicago Architecture Foundation River

Cruise. Because it abuts Congress

Expressway, the plant employs special

evaporative condenser cooling towers to

minimize any plume that could prove

hazardous to drivers on the expressway.

The next plant to come on line was

P3, in 1997. It is located in the Blue

Plant P1 is located at the corner of State and Adams in an area zoned for retail, allowing the first floor to be occupied by a pharmacy while the rest of the building houses chillers, ice tanks and cooling towers.

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Plant P2 is located at Franklin and Van Buren, adjacent to the Congress Expressway. Its 2 million-gal ice tank has a capacity of 125,000 ton-hr.

Co

urt

esy

Ther

mal

Ch

icag

o.

14 District Energy / Second Quarter 2012

Cross-Blue Shield of Illinois Tower on

East Randolph Street, a building that

has its own amazing history. Originally

built as a 32-story tower, the structure

grew by 24 stories in 2007 as the result

of an ambitious expansion project,

which in turn presented new challenges

for Thermal Chicago. “Our cooling tow-

ers were on the roof, so they had to

build the support structure around the

towers and then complete the floors

above all the way to the top,” recalls

Thermal Chicago Corporation President

Dave Bump. “Meanwhile, we had to keep

the old towers running until we demol-

ished them after switching over to the

new towers on the new roof. Then the

remaining stories were filled in.” At that

stage, two additional Trane compressors

were added, augmenting the seven exist-

ing Mycom chillers and 100,000 ton-hr

of ice storage in the plant.

Plant P4 is located in the basement

of the Merchandise Mart, a major whole-

sale design center and international busi-

ness center facing the Chicago River. The

Mart, which spans two city blocks and

rises 25 stories, had its own chiller plant

dating to the 1940s that looked “like

something off an old battleship,” says

Bump. In 1987 ice storage was added. In

2000 the system became integrated with

the Thermal Chicago network, and the

plant was substantially expanded with

© 2012 International District Energy Association. ALL RIGHTS RESERVED.

old equipment retired. The plant uses

river water as a heat sink.

The newest plant, P5, is also invis-

ible from the street, located under IBM

Plaza along the river, next to Trump

Tower. Unlike the other plants, it does

not contain ice storage, instead housing

10 Trane chillers that can chill water to

34 degrees F.

The original decision to build a sys-

tem based largely on ice storage was

driven by the scarcity of available land

in downtown Chicago. Ice storage offers

a relatively compact storage volume

compared to chilled water, making it a

more practical solution. “If you had put

a water tank everywhere you’ve got an

ice tank, real estate would have become

a real problem,” says Jack Kattner of

Kattner Associates, marketing and sales

representative for Thermal Chicago.

Using ice also enables the system to

pump a much colder temperature of

water to its customer buildings, allow-

ing them to use smaller air handlers

and reduce the amount of metal

required for internal systems.

Unlike many district cooling sys-

tems, which utilize uniform equipment

throughout, Thermal Chicago employs

diverse methods including ice tank stor-

age, ammonia chillers and river water

chillers, as well as traditional-type

chillers. At the heart of it all is thermal

Plant P4 is situated in the basement of the Merchandise Mart, which in 2007 became the world’s largest building to receive LEED® (Leadership in Energy and Environmental Design) for Existing Buildings certification.

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storage, which allows ice to be made

during the night, when electric demand

and cost are low. It is then stored and

allowed to melt slowly the following

day to meet demand. This reduces

System Snapshot: Thermal ChicagoSystem Owner-Operator: Thermal Chicago CorporationLocation: Chicago, Ill.

Chilled-Water System

Startup Year 1995

Number of Buildings Served Approximately 100

Total Space Served 45 million sq ft

Total Capacity 101,000 tons including 315,000 ton-hr ice thermal energy storage:

Plant P1 – 20,000 tons (66,000 ton-hr ice tank)

Plant P2 – 23,000 tons (125,000 ton-hr ice tank)

Plant P3 – 23,000 tons (100,000 ton-hr ice tank)

Plant P4 – 20,000 tons (24,000 ton-hr ice tank)

Plant P5 – 15,000 tons

Total Number of Chillers 44

Fuel Type Electricity

Distribution Network Length 8 trench miles

Piping Type Welded steel with epoxy coating

Piping Diameter Range 12 to 30 inches

System Pressure 100 psig

System Temperatures 34 F supply/54 F return

Source: Thermal Chicago.

District Energy / Second Quarter 2012 15

Part of the piping network above the ice tanks on the roof of Plant P2. A thin concrete slab covers the tank and the piping distributes water evenly across the tank sections.

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stress on the grid. By using ice, Thermal

Chicago can avoid 40 MW of peak load

on the grid for a short period of time

and 20 MW for a longer period of time.

The advantages of operating chillers at

© 2012 International District Energy Association. ALL RIGHTS RESERVED. 16 District Energy / Fourth Quarter 2011

night are amplified in Illinois, which gets

roughly 40 percent of its electricity from

nuclear plants – about twice the national

average. As Bump explains, “Large nucle-

ar plants don’t like to load-follow; they

benefit from a nighttime load, which we

provide. In return, we purchase our elec-

tricity at a reduced rate.”

On the water management side,

the Thermal Chicago system has a total

capacity of approximately 8 million

gal, which flow through 8 trench miles

of distribution piping and hundreds

of individual heat exchangers. The

company has its own in-house Ph.D.

chemist who oversees long-term asset

16 District Energy / Second Quarter 2012

preservation, trains other staff and pur-

chases chemicals as commodities. Staff

continually monitors the pH levels,

conductivity and microbiological activ-

ity, taking action as needed to preserve

optimum water quality. The water in

the distribution network is dyed pink

in order to distinguish it from the city

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Where’s the Heat? Given the fact that Chicago is in

a northern climate where most major

cities are served by some type of dis-

trict heating network, it is interest-

ing to note that the Windy City does

not have such a system. In theory,

a heating network could have been

installed at the same time as the cool-

ing network. However, many buildings

in the Loop have electric baseboard

heating, historically a practical option

considering the relatively low cost of

nuclear-generated electricity in Illinois.

Converting those buildings to a hot-

water system would prove impractical.

Today, there is a mixture of buildings

with electric heat and internal gas-

fired boilers, but a neighborhood of

hydronic buildings would have to be

found in order to support a district

network.

Tour Thermal Chicago With IDEA Tours of the Thermal Chicago

system will be a highlight of the IDEA

103rd Annual Conference and Trade

Show at the Hyatt Regency Chicago,

June 29-July 2, 2012. The conference

theme is “Cooler, Cleaner, Cities,”

and it promises to be filled with

stimulating presentations, workshops

and networking opportunities, along

with a lively trade show featuring

top engineering, manufacturing and

consulting firms from around the

globe. For more information, visit

www.districtenergy.org/calendar.Plant P1 began serving the first Thermal Chicago customers in 1995. Today it contributes 20,000 tons of capacity to the interconnected district cooling network.

© 2012 International District Energy Association. ALL RIGHTS RESERVED. District Energy / Second Quarter 2012 17

water supply in the event of a leak. It is

notable that no chemicals are added to

the condenser-side water used from the

Chicago River.

Customer Benefits Thermal Chicago operates on an

economic dispatch model that ensures

customers are getting the most eco-

nomical cooling available. The company

uses variable-frequency drives and a

mix of electricity sources and contracts.

All plants have multiple feeders com-

ing in from different substations, and

the whole system is interconnected; if

a substation goes down and takes out

part of a plant, the rest of the plant is

still operational, together with all the

other plants that are feeding into the

system.

Connecting to the Thermal Chicago

network eliminates the electricity

demands of on-site chillers and cool-

ing towers, of course, but it can also

help customers lower their other elec-

tric costs as well. As Bump explains,

“Roughly 50 percent of a building’s

peak electricity usage is for air condi-

tioning. By using district cooling, they

do not need major electricity-using

chillers, cooling towers and associated

pumps. They instead have a very flat

electric load profile, which is very

attractive in a deregulated market to

our retail energy suppliers. We believe

those customers can get more favorable

electric rates because of those predict-

able, flat load profiles.”

Because several of its customer

buildings have multiple tenants with

diverse energy needs, Thermal Chicago

can provide separate process feeds and

individual metering as required. For

data centers and other mission-critical

customers, the system offers the highest

possible level of reliability. In addition,

Thermal Chicago has a fiber optic sys-

tem that enables its personnel to moni-

tor every customer building from any of

the five plants or even via their smart-

phones. “Customers appreciate the fact

that we have someone in our control

room monitoring their building 24/7,

and there have been many times when

we’ve alerted them to issues that they

had not even noticed yet,” says Bump.

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An insider’s knowledge.

An outsider’s perspective.

Kattner Associates gives you both.

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District Energy / Second Quarter 2012 17

In addition to providing reliable

and efficient cooling service, Thermal

Chicago offers important opportuni-

ties for customers with respect to

their sustainability goals and their

desire to earn points toward their

LEED® (Leadership in Energy and

Environmental Design) certification.

As Kattner explains, “We work with

these customers in four key areas.

The first is refrigerant management

and commissioning, which are key

aspects of our full-time business.

Second, we use a reasonable amount

of nighttime electricity, which is largely

nuclear-based, so there’s a carbon

footprint reduction (during peak peri-

ods, some of the customers’ electric-

ity would be coming from coal- or

gas-fired peaking plants). Third, we

use river water as a heat sink. If all of

our customers were using individual

cooling towers, they would evaporate

water at a much greater rate than we

do. Fourth, it’s possible for customers

to earn additional points by providing

bike racks, fitness centers and other

amenities such as green roofs and

solar collectors that can occupy space

that would have been utilized for

their on-site chillers.”

Besides the reliability, environ-

mental benefits, electricity and water

savings, use of the Thermal Chicago

system saves customers on up-front

and ongoing capital and maintenance

costs. It allows preservation of valu-

able space in the buildings by elimi-

nating all the traditional water chilling

and cooling tower equipment and thus

allows greater architectural freedom

in new buildings.

With a solid track record earned

over its 17 years of operation, Thermal

Chicago now serves about 45 million

sq ft of building space, or about 20

percent of the downtown market. That

leaves plenty of room for growth,

and the company sees strong poten-

tial in building renovations and new

construction now that the economy

is starting to pick up. Regardless of

the challenges posed by any of those

future projects, Thermal Chicago can

draw on its legacy of Chicago-style

ingenuity to get the job done.