Pictured are (kneeling left to right)

Kevin Anttila, Griewahn and Thomas Doran; (standing left to right) Kutches, Erik Samuelson and Roger Rantala

Students Audit Dining Services' Energy Use


In a research project aligned with NMU’s sustainability efforts, students from the climate control technology program completed the first phase of a Dining Services energy audit. They spent most of last semester collecting data from refrigeration equipment in the Marketplace and CatTrax facilities. The objectives were to reveal total energy consumption, suggest more efficient alternatives to existing commercial equipment, implement a preventive maintenance schedule to deter excessive service calls and propose a maximum five-year payback plan on investment.


“The ultimate goal is to reduce overall energy costs for Dining Services,” said instructor Nicholas Griewahn (Technology and Occupational Sciences). “Because of the time limitations of a semester and the amount of equipment we plan to examine, we’re approaching this in multiple phases. We started with the refrigeration equipment. Later we’ll do a more in-depth analysis of issues that surfaced this semester and review mechanical systems used in foodservice operations.”


The refrigeration equipment included both walk-in and reach-in coolers and freezers. Instruments like the one pictured were used to determine temperature, humidity and average compressor run times. Other data was gleaned from visually observing the condition of door gaskets, hardware and general system operations.


“It’s great to get hands-on experience in an actual work environment where the equipment is spread out and you’re dealing with people and have to be more professional,” said student Eric Kutches. “It’s different than in a lab, where everything is right there and the only people around are your instructor and fellow students.”


Three of the walk-ins use open loop, water-cooled condenser systems. The water is not recycled for any purpose, so Griewahn said it’s basically considered a loss. Students measured the usage with one-gallon containers over a specified time period. Though not a precise method, it provided some insight as to how much water cycles through the units and the consumption was estimated at nearly $9,000 per year.


The special topics class recommended retrofitting with new air-cooled condensers and variable-speed evaporator fan motors. Based on the initial investment of $10,932 and the projected annual savings of $10,237, they figured the upgrades would pay for themselves in about 13 months.


A final report on the first phase will include full cost breakdowns and other suggested changes that could be implemented to improve energy use trends. The directed study research project was supported in part by a Wildcat Innovation Fund award. The class presented its preliminary findings at the Celebration of Student Research and Creative Works in April.



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Updated: June 13, 2012

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