The University of Akron, in Akron, Ohio, has a reputation for being environmentally active in its use of energy resources. Not only does it have an Office of Sustainability that acts as a liaison on all capital planning projects; it also has the FirstEnergy Advanced Research Center that develops energy technology to generate efficient electric power with minimal carbon dioxide emissions. The university also fine-tuned its energy systems to get the most value out of them and its newer buildings were built to LEED standards.

The university only had two things holding it back from being an energy efficiency super star: a large enough staff to make needed upgrades and the lack of money to pay for them — problems all too common with colleges and universities around the country.

INCENTIVES

Then three things happened that solved all of the university's problems.

First, the Ohio state government passed House Bill 251 which called for a 20 percent reduction in energy consumption and greenhouse gas emissions at public institutions in the state. That would seem daunting since it had already honed its energy systems to be as efficient as possible. And it would have been disastrous without the other two events.

Second, the Ohio Air Quality Development Authority (OAQDA) offered the university $60 million in financing via bonds to help it achieve the goals set by the state.

“The University of Akron is extremely pleased to make use of QECB financing as part of the overall financial package to assist us in significantly cutting energy costs and greenhouse gas emissions," said David J. Cummins, vice president of Finance and Administration and CFO. "This project will improve both the indoor and outdoor environment in numerous buildings across campus, while also benefiting the residents of our county and region.”

The third thing that happened was Johnson Controls made the university an offer it couldn’t refuse — a guaranteed energy performance contract.

That contract means the upgrades will be paid for by the savings in energy and utility costs over the term of the 15 year contract. The university will not pay upfront costs and Johnson Controls guaranteed the contracted savings. The company has been successful in many similar ventures, performing more than 2,500 performance contracting projects with guaranteed savings of $7.5 billion.

EXTENSIVE IMPROVEMENTS

University of Akron has more than 27,000 students and offers in excess of 300 undergraduate and graduate programs. Located in metropolitan Akron, the university has more than 80 buildings on 218 acres. Since 2000, it has added 22 buildings, completed 18 major additions, acquisitions and renovations, and created 34 acres of green space.

At the end of the contract, the upgrades will have been made campus-wide and will include everything on campus that consumes energy including security lighting upgrades on parking decks, energy efficient lighting, natural gas monitoring, improved efficiency for high temperature heating water and chilled water, demand-response monitoring equipment, and water-conservation measures. Other improvements at individual buildings include interior/exterior lighting, mechanical upgrades, building and window improvements, utility metering, building automation, and energy-efficient laboratories.

“This is one of the largest upgrade programs of its kind,” said Dave Peters, regional vice president and general manager for Johnson Controls, Building Efficiency. “By using this type of financing the university can reduce its energy use, enhance the campus environment and shrink its carbon footprint — all while conserving financial resources.”

Johnson Controls’ building management system, Metasys^Ⓡ will be combined with its Panopix^Ⓡ cloud-based system to collect building data and offer improved visibility into building operations to optimize energy savings and building performance.

FLOW MEASUREMENT

As famed engineer W. Edwards Deming once observed, “You can’t manage what you don’t measure.” Nowhere are those words more true than when using a building management system such as Metasys. If accurate data doesn’t go into the system, optimum efficiency cannot be achieved. And at the University of Akron the two biggest users of energy are their hot and chilled water systems.

“The chilled water was pretty straight forward,” said David Musser, mechanical engineer and project manager at Akron. “But it was the hot water system that had always been a challenge. You see, we run water at 400 degrees Fahrenheit and four hundred pound per square inch pressure. That creates some measuring difficulties. A few years ago we weren’t making our own steam. We were buying it locally because it cost less and running it through the heat exchanges in dorms and other buildings. But we had no way to know if what the steam company was billing us for was accurate. We wanted our own measurements to verify, so we began looking at flow meters. We didn’t want intrusive metering because it was expensive to install, we’d have to shut down the system to calibrate it, and it wouldn’t be likely to last long in that environment. We tried ultrasonic clamp-ons because they were non-intrusive and the technology made sense for our application. The only problem, and it was a big one, was the gel that held the transducers to the pipe would break down because of the 400 degree temperature and the meter would start giving ridiculous readings."

HOW ULTRASONIC METERS MEASURE FLOW 

The technique most ultrasonic flow meters use is called transit-time difference. It exploits the fact that the transmission speed of an ultrasonic signal depends on the flow velocity of the carrier medium, kind of like a swimmer swimming against the current. The signal moves slower against the flow than with it.

When taking a measurement, the meter sends ultrasonic pulses through the medium, one in the flow direction and one against it. The transducers alternate as emitters and receivers. The transit time of the signal going with the flow is shorter than the one going against. The meter measures transit-time difference and determines the average flow velocity of the medium. Since ultrasonic signals propagate in solids, the meter can be mounted directly on the pipe and measure flow non-invasively, eliminating any need to cut the pipe.     

A HIGH-TEMP ULTRASONIC SOLUTION

“When we asked our local distributor rep, Brian Papa from Chaltron, if he had any ideas, it turned out one of the companies he represents had recently developed a high-temperature ultrasonic flow meter,” said Musser.

“What Dave experienced is typical of ultrasonic transducers in a hot environment," said Papa. "Depending on the meter, the gels or pads used for acoustic coupling between the ultrasonic transducers and the pipe have a limited temperature tolerance. Also, high temperatures accelerate the aging of the transducer’s piezzo elements and reduce their operating life.

“That’s why my client, FLEXIM Americas, developed their WaveInjector transducer mounting fixture," he continued. "It permits the transducer to be mounted at a safe distance from the pipe while still maintaining accurate readings. It enables a set of standard transducers to operate accurately at temperatures ranges from -160 up to 440 degrees Centigrade.”

“We bought one and Brian oversaw the installation,” said Musser. “The first thing we found out was that the steam company was under billing us. It turns out the ultrasonic had a much better turn down than the other meter and was much more accurate on low flow.

“Now with the performance contract, we’ve ordered 28 more FLEXIM meters with the special transducer mountings," Musser continued. "The contractor initially wanted to use some other meter, but we showed him the eight we had already installed, pointed out that they need no calibration and are excellent on low flow measurements and they can communicate directly with a building management system. I think the contractor realized that ultrasonics would be an asset to him and help him fulfill his part of the contract.”

To date every thing on the performance contract is on or ahead of schedule, and the ultrasonic meters will soon be communicating with the Metasys building management system.

Publication date: 10/8/2018

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