World's Largest Penguin Facility Counts on Condensing Boiler
A condensing hydronic boiler provides supplemental heat as required to maintain the temperature of the water-source, heat-pump loop system.
In April 2016, the Detroit Zoo, located in Royal Oak, Mich., opened the largest penguin facility in the world. The Polk Penguin Conservation Center is a 33,000-square-foot, iceberg-shaped structure that is home to more than 80 penguins of four species.
One of the most dramatic features of the Polk Penguin Conservation Center is a chilled, 326,000-gallon, 25-foot-deep aquatic area where visitors can watch penguins as they swim and glide through the water. There are also two acrylic underwater tunnels that offer views overhead and below the penguins in their naturalistic habitat.
The Detroit Zoo is committed to environmental leadership and earned the 2015 Green Award from the Association of Zoos and Aquariums for its efforts. So when the zoo began planning its new $30 million penguin center in 2012, the goal was to build and operate the facility in the most energy-efficient and sustainable manner possible.
The zoo tapped architectural firm Albert Kahn Associates in Detroit to design the Polk Penguin Conservation Center.
The zoo wanted to create the optimal environment for the penguins’ welfare, so they dictated that the air temperature be maintained at a near-freezing 40° F.
To most efficiently accomplish this goal, Albert Kahn Associates designed the mechanical system to reclaim and reuse rejected heat energy associated with the year-round cooling requirements of the exhibit and provide heating and cooling to meet seasonal requirements for public and husbandry areas of the facility.
Johannes Palm at Albert Kahn Associates recommended a condensing hydronic boiler for the application.
“The condensing hydronic boiler will provide supplemental heat as required to maintain the temperature of the water-source, heat-pump loop system,” explained Palm.
The condensing hydronic boiler that best met the design specifications was the Cleaver-Brooks ClearFire®-C fully condensing boiler. Designed to operate most efficiently in systems with low return-water temperatures, this boiler can achieve efficiencies up to 99%. Its modulating, pre-mix burner delivers 5:1 turndown and less than 20 ppm NOx.
The public areas of the Polk Penguin Conservation Center are conditioned using water-source heat pumps. The husbandry area, where back-of-house operations take place, is conditioned using a water-cooled, variable refrigerant-flow system coupled with a dedicated outside air ventilation heat-pump unit. The habitat is conditioned using water-cooled chillers that reject their heat to the heat-pump loop.
The heating requirement of the facility is provided in part by the heat recovered from the chilled water system. Supplemental heat and backup heating is provided by the high-efficiency, gas-firing condensing hydronic boiler.
“If the heat pump loop temperature falls below 60°F, then the boiler will be used to inject heat into the water-source, heat-pump loop,” explained Catherine Van Wormer, sales engineer at D.J. Conley Associates, located in Troy, Mich. “With the low water temperatures utilized in a heat-pump loop system, a condensing boiler is the perfect solution.”
The ClearFire-C condensing hydronic boiler was installed in the facility in the summer of 2015, and start-up was completed in February 2016.
The condensing hydronic boiler system in the new Polk Penguin Conservation Center is expected to be 15 to 20 percent more efficient than the traditional boiler system that operated in the zoo’s former Penguinarium, which was remodeled in 1985. The Detroit Zoo’s Penguinarium, built in 1968, was the first facility in North America designed specifically for penguins.