Marlins Park, the new home of baseball’s Miami Marlins, is the first retractable roof facility in the world to earn LEED Gold certification. Photo courtesy of Robert Vigon/Miami Marlins

Major League Baseball’s newest stadium gem is also a beauty when it comes to sustainability.

Marlins Park, the new $634-million home of the Miami (nee Florida) Marlins, is the first retractable roof facility in the world to earn LEED Gold certification. The ballpark, which has the smallest seating capacity amongst MLB stadiums at 37,442, covers 2.8 million sq. ft. and sits on the site of the former Orange Bowl in the Little Havana area of Miami. Two 450-gallon aquariums on either side of home plate highlight the many eye-grabbing components of the ballpark

“When you have buildings that have transient occupancies and use large amounts of resources in a short amount of time - in certain cases using up as much energy as a small city - you have to know exactly what you want to focus on to provide energy-efficient solutions,” says M-E Engineers Director of Sustainable Design Mohit Mehta, LEED AP BD +C. M-E Engineers was the MEP firm of record on the project.

For starters, site water consumption was reduced 67% through the use of native and adaptive plants and drip irrigation. In addition, effective strategies were implemented to control, reduce and treat storm water runoff before it leaves the project site.

The ballpark features waterless fixtures such as Kohler and Zurn waterless urinals, Zurn low-flow toilets, Zurn lavatory faucets and Speakman low-flow showerheads.

“When you add all that up, the project realizes more than 50% potable water savings within the ballpark,” Mehta states.

A majority of the cooling is generated by two large Trane water-cooled heat recovery chillers. “We are able to consistently capture waste heat from the chillers for heating domestic water in the ballpark,” Mehta says. “As a result, under full capacity, we expect the domestic water PVI boilers serving the service level and main concourses to be off a majority of the time. The savings with this approach are significant.”

Trane energy recovery systems are used in the player locker rooms where the incoming outside air is pre-treated by the exhaust air streams, substantially reducing the load on the cooling coils. The ballpark also realizes additional efficiencies through the use of high-efficiency Halton Capture Jet kitchen hoods in the concession areas.

“The kitchen and concession areas exhaust a ton of air and need a lot of makeup air,” Mehta says. “The kitchen hoods contribute to an average reduction in airflow of about 29%.”

One of the main reasons for the retractable roof facility was to shield fans from the sometimes uncomfortable South Florida heat, humidity and afternoon downpours. Mehta notes keeping the environment comfortable in such a large facility is a delicate undertaking.

Cooling the ballpark’s bowl must be done gradually and in stages. “You have to be very careful how you bring the temperature down once the roof closes. We’re constantly monitoring the temperature, humidity and dew point in the space to avoid condensation,” he says. “It takes about four hours to bring the space down to optimum temperature and humidity conditions.”

The ballpark uses demand-controlled ventilation technology, while CO2 sensors monitor the occupancy of the building. “We’re continuously minimizing the ventilation air based on occupancy and that saves additional energy,” Mehta says. “There is a sophisticated building management system that controls the sequences. This is very critical and a huge challenge to achieve this.”

Mehta stresses the LEED Gold designation was the result of a team effort. When it comes to sustainability, “Everybody wants to know what the silver bullet is,” he says.

“The ballpark needs to be analyzed as an integrated whole to take advantage of synergistic effects – to ensure that the total environmental impact is minimized. This is a big project in a harsh climate. We’re predicting almost 25% energy savings compared to the ASHRAE 90.1 baseline. It’s very satisfying.”