Summary
For more than 100 years, The Toledo Zoo has been creating memories for the young and old alike. Each year, nearly one million people visit the zoo to explore the world and its fabulous creatures that live in displays resembling natural habitats, from the frozen Arctic tundra to the hot Sonoran Desert. Guests encounter animals, large and small, from mammoth African elephants to the tiniest toads, or stroll the grounds to view historic buildings constructed in the WPA-era.
Challenge
The Toledo Zoo’s Museum of Science building, constructed in the 1930s, houses offices, animal exhibits, the education department, a theater and a large hall sometimes used for special events. The building was being served by an older 80-ton Trane chiller with two 40-ton compressors, one of which had stopped functioning years earlier. The zoo wished to increase its cooling capacity to include the indoor theater, while replacing its aging HVAC system. With the facility’s electrical substation also nearing capacity, crossing the peak demand level, even once, would require the zoo to upgrade its service, resulting in a substantial increase in utility costs. The zoo sought a solution that would allow them to keep the building comfortable for employees and guests, without increasing electricity consumption.
Solution
Trane met with zoo owners and their consultant engineering firm, JDRM Engineering of Sylvania, Ohio, to discuss their repair/replacement options. A Trane EarthWise™ Ice Enhanced Air-Cooled Chiller Plant System was presented as an alternative solution. The Trane system is a comprehensive approach to HVAC design that couples an air-cooled chiller with ice tanks, integrated with a standard system controller and operator interface. After reviewing the benefits of the Trane EarthWise™ system, the zoo moved forward with its upgrade plans.
Meeting budget and aggressive scheduling requirements
As a levy-supported organization, the Toledo Zoo was able to take advantage of the Ohio State Term Schedule (STS), a cooperative purchasing program that allows members to use prenegotiated contracts to obtain most favored pricing. Enjoying the cost-saving benefits of the cooperative, the zoo was able to stay within its budget parameters. Rather than spending time initiating a bidding process, evaluating proposals and selecting a vendor, the zoo moved quickly, working directly with Trane, a preapproved Ohio STS vendor. Within days, Trane submitted a proposal to the owner and engineering consultant. The proposal was quickly approved and equipment was released. A process that normally takes months was completed in just eight days.
Bypassing substation upgrade
Instead of installing another 80-ton chiller to replace the aging equipment, the Trane EarthWise™ system, with one 40-ton air-cooled CGAM chiller, combined with two ice storage tanks providing 40 tons of melt ice cooling, meets the zoo’s needs. With the ice storage, the chiller required to cool the building is half the size of what would be needed with a conventional system, reducing project first costs.
Shifting the load
The chiller builds ice at night during off-peak hours when the building load is low. During the day, the ice is used to provide cooling for the building. The ice tanks help the zoo reduce overall campus electrical consumption and manage peak demands, helping the zoo to bypass a potential costly substation upgrade. Reducing costs, improving serviceability The museum building’s 80-ton chiller, which included a condenser located on a freestanding structure on the roof and a large compressor located in the basement, was removed. The new Trane 40-ton air-cooled scroll chiller was installed on the ground behind the building for easier serviceability. The smaller-sized chiller with its reliable, efficient design keeps maintenance costs lower.
Simplifying scheduling and control
Facility managers have full access to the system using the web-based Trane Tracer™ SC building automation system (BAS). The BAS makes scheduling, reporting and programming chores simple, improving efficiencies, increasing comfort and reducing energy costs. Trane can also access the system remotely should assistance be needed.
Results
Replacing its older 80-ton chiller with a Trane EarthWise™ Ice Enhanced Air-Cooled Chiller Plant System, including a 40-ton air-cooled CGAM chiller, two ice storage tanks and controls, has allowed the Toledo Zoo to increase capacity and reduce its electricity consumption, helping to avoid a costly substation upgrade. The smaller-size chiller, installed on the ground rather than on the roof and in the basement like the old chiller, reduced initial first costs of the upgrade project, improves serviceability and keeps maintenance costs lower.
The Toledo Zoo is pleased with the performance and efficiency of the ice storage, with the system often times going for days without running the chiller. “On an average summer day, the chiller doesn’t kick in at all,” said Dave Ruhl, assistant director of facilities construction, The Toledo Zoo. “Much of the time, during the day, we’re just running on ice.”
About Toledo Zoo
Built during the Big Deal, the Museum of Science building is one of several historical buildings on The Toledo Zoo campus. A 40-ton Trane air-cooled chiller designed for efficiency, combined with two ice storage tanks, helps reduce campus electrical consumption.
