In the world’s largest sports film library at NFL Films in New Jersey, the temperature in the vault needs to be maintained at 12˚C to keep the films preserved. A failure in the air-conditioning systems could therefore be nothing less than catastrophic. In addition to this, cool temperatures are critical during the production of television programmes at the complex, as under the hot studio lights the make-up of the shows’ hosts can quickly melt if the air-conditioning fails. So for NFL Films, a reliable air-conditioning system is a lot more critical than in a conventional office building.
It was therefore a major problem when one of the two old chillers (that generate cooling in the air-conditioning systems) became unreliable. The mechanical contractor suggested replacing parts of the chillers. “But we did not have confidence in their ability to understand what the problems were,” says John Rauch, Operations Manager for Veolia Energy North America, the company that provides building operations services for NFL Films headquarters in Mount Laurel, New Jersey.
New solution cuts operating costs
The decision was made to install two new Smardt chillers, provided by Tustin Mechanical Services of Hammonton, New Jersey. Smardt chillers use oil-free centrifugal Danfoss compressors. Five Danfoss Turbocor compressors were installed on each chiller. The oil-free centrifugal compressor technology boosts energy efficiency and cuts operating costs. “It provides much better efficiencies than the conventional oil-lubricated compressors on our old machines. Since we’ve installed the Smardt chillers, we’ve realised a 10-12% reduction in the consumption of electricity on a monthly basis. The NFL Films complex uses a lot of electricity — about 11 million kWh per year with the old machines — and with these new machines we have achieved a 10% reduction, using under 10 million kWh this year,” John Rauch says.
Less capacity per compressor reduces impact of failure
The new chillers are not only more energy efficient but also more reliable. There were previously four compressors on each of the two old machines, with 25% of the capacity on each compressor. “With the Smardt chillers we have 10 compressors, five on each machine. Instead of 25% capacity per compressor, we have 10%, so the impact of a failure on the operation is a lot less. This was a deciding factor in choosing the Smardt chillers,” says John Rauch.
The variable frequency control in the chiller design means that the machine consumes only the level of electricity that’s required to meet the cooling need at a particular point in time. Rodney Moore, General Manager at Tustin Mechanical Services, says: “Conventional machines have a big motor that’s always running. With the Danfoss Turbocor technology, a combination of variable frequency drives and inlet guide vanes on each compressor allow for optimum energy efficiency. This happens by slowing down the speed of the compressors and closing the inlet guide vanes when there is a low demand for cooling in the building. Moreover, the new machines are running more quietly and you don’t need any vibration isolators.”
The main goal was to acquire reliable, energy-efficient chillers that would last 25 to 30 years. “With the Smardt chillers and their Turbocor technology, we believe that this is the best investment we could have made,” concludes John Rauch.
Facts about chillers:
Both chillers went online in June 2008. Since then, Chiller 1 has accumulated over 6,000 operating hours and Chiller 2 has operated over 8,000 hours. Both machines have run without any breakdowns and have performed exceptionally. See the chillers in the picture to the right.