Stevens Institute of Technology: Babbio Center

Background

The Babbio Center and attached 60,000-square-foot parking garage were built in 2005 and are among the newest structures on the Stevens campus. When the campus central steam plant was decommissioned in 2015, Stevens saw an opportunity to implement further energy efficiency upgrades at the Babbio Center through retro-commissioning. Improvements have been made gradually, with the goal of maintaining occupant comfort in the multi-purpose building that includes classrooms, offices, and conference space.

Babbio is a six-story building used primarily for classes Monday through Saturday, 8am to 10pm. A majority of the classrooms are used by the School of Technology Management and the School of Systems and Enterprises. The building also contains an auditorium and the Center for Complex Systems and Enterprises, which includes an energy intensive, high-tech research center and lab.

Solutions

Stevens chose to decommission the central steam plant because the aging, leaking infrastructure needed to be replaced, and a new campus-wide central plant was not economically feasible. The school opted for distributed generation, dispersing small cogeneration units, chillers, and high-efficiency boilers throughout campus. To address cost concerns, Stevens entered into a power purchase agreement (PPA) with American DG. The PPA was expanded as the units were gradually installed throughout the main campus academic buildings.

Primary energy efficiency measure upgrades included:

Chiller Replacement: Absorption chiller replaced with a new gas engine chiller
Condensing Boiler Upgrade: Steam heat exchanger replaced by two condensing boilers
Variable Speed Pumping: Implemented on chilled water pumping for AHU coils, as well as hot water pumping

To improve temperature controls, variable frequency drives (VFDs) were installed in November 2016 on two AHUs that control water flow through the boiler for a cost of $13,000. While these AHUs were originally outfitted with VFDs, they had been replaced with motor starters over the years. The new VFDs resulted in improved temperature control of the fan discharge and have reduced energy consumption since the pumps now provide heating/chilled water in only the quantities needed.

The Babbio Center was built with defective reheat valves from Belimo. The valves would fail in the open (or closed) position, resulting in space overcooling or overheating. Belimo provided replacement valves, a cost of $43,000 including labor, for free under the original warranty. Over the 2016-2017 winter break the Stevens Facilities team began installing the replacement valves in the classrooms and some offices. Replacement and commissioning of these valves has allowed Stevens to run Babbio’s air handlers to produce 55-degree air and use the reheats to provide local comfort, improving the learning environment. Since the VAVs were able to modulate air flow, there was better control of temperature, and energy has been conserved as well. To date, approximately 40 of the 120 valves have been replaced, with the goal of completing the project by the end of summer 2017.

ANNUAL ENERGY USE

ANNUAL ENERGY COST

ANNUAL WATER USE

ANNUAL WATER COST

ANNUAL PLANT ELECTRICITY USE

ANNUAL PLANT ELECTRICITY COST

IN BUILDING ENERGY USE

IN BUILDING ENERGY COST

ACROSS NETWORK USE

ACROSS NETWORK COST

ANNUAL EMISSIONS

USE

COST

ANNUAL WASTE COST

ANNUAL WASTE USE

Babbio Exterior

Babbio Central Stairway

View from Babbio Atrium

Stevens Institute of Technology: Babbio Center

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Babbio Exterior

Babbio Central Stairway

View from Babbio Atrium