KEEPING TREASURES COOL

The Art Institute of Chicago recently replaced a three-decade-old 500-ton chiller unit. According to William Caddick, the executive director of facilities for the institute’s physical plant department, this 800,000-plus square-foot cooling project involved much more than just swapping in a new chiller.

“To properly maintain so many valuable works of art requires that humidity and temperature be kept at precise levels,” explained Caddick. “Adding to the challenge is a varied building design that includes multiple layers and high ceilings, as well as many skylights and revolving glass doors which add to the heat load.”

Additional project requirements included ease of operation, long-term cost savings, and the ability to meet very tight space and time constraints.

Carrier Commercial Services replaced the institute’s aging chillers, one of a series of four 500-ton chillers, with a 750-ton 19XR Evergreen® unit. Fitting into the existing footprint of the old unit, the new unit expanded the institute’s cooling capacity up to 25%, minimizing mechanical room space usage and sound disruptions. The units also provide environmentally sound, non-ozone depleting HFC-134a refrigerant, according to Carrier.

Under the right conditions and proper operation, Caddick explained, a chiller with increased capacity accomplishes the same cooling using fewer chillers, thereby conserving significant energy.

Also, to simplify indoor climate management for the entire institute — including the museum, classrooms, studios, auditoriums, food services, and administration offices — a Carrier Comfort Network® (CCN) was installed. According to Carrier, by utilizing Windows-based ComfortWORKS® software, the temperature and humidity throughout the institute can be controlled from one pc.

The Art Institute of Chicago received the award for its foresight in investing in energy-efficient, environmentally sound technology.

41 STORIES OF A/C

A Carrier environmental award was also presented to the office building at One East Wacker Drive. The 41-story complex houses major corporations, an atrium, a conferencing facility, several food service venues, and more.

Building management firm Jones Lang LaSalle had more requirements than just a pleasant indoor climate. Vice president Fred Wickham explained that the firm needed a complete system that was not only reliable, but also energy efficient.

“Our previous system required a significant amount of energy. We were looking to achieve significant operating cost savings with the new system,” said Wickham.

With the help of Temperature Equipment Corporation (TEC), a Chicago-based independent distributor of Carrier products, the building management firm replaced two 1,200-ton chiller units with three 700-ton 19XR Evergreen centrifugal chillers with unit-mounted variable-frequency drives (VFDs). According to Carrier, both chillers and the VFDs are cooled by HFC-134a.

The manufacturer also said the unit-mounted VFDs add a new dimension to chiller efficiency. Chicago-based McGuire Engineers designed the multiple chillers. The design gave the building the capability to stage chiller usage, gradually starting one up at a time as cooling loads increase during the day. The energy consumption can also be decreased during the building’s off-peak periods. Any-time the building is not running all three chillers at full load, they are conserving energy.

Carrier says that McGuire’s design also allows the building to achieve additional savings through the use of a Carrier chiller plant control system and a plate frame heat exchanger. During the winter, the chillers and the VFDs — and ultimately the building — will receive “free cooling” by utilizing cold water from the Chicago River to cool the entire system.

“In the end, we were impressed by the estimate life cycle cost of the equipment, which was shown to us by TEC using Carrier’s Chiller System Optimizer software,” Wickham said.

Like the Art Institute of Chicago, the 41-story office building was also equipped with a Carrier Comfort Network to allow temperature control from a PC.

“We are pleased that Carrier chose to recognize these building owners as environmental leaders,” said Gary Stern, TEC’s vice president, Applied Systems. “We hope the recognition will encourage other building owners to challenge their consulting engineers to design systems using equipment and technologies that provides both a sound financial and environmental return.”

Publication date: 07/15/2002