Comfort At Work: Case Study

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Out with the old, in with the new.

Asheville, N.C. -- Barney Woodson and the big ol' green Carrier 19C centrifugal chiller had a few things in common.

Barney Woodson in his office.
 



Both of them started working for the tenants of the Branch Bank & Trust building 33 years ago. In that time, neither of them had missed a day of work nor been late. But there the similarities ceased.

The 19C ended its career shortly before Christmas as welders torched it into three manageable-sized pieces. After the shopping rush was over and area streets could be blocked off a few days into the new year, the chiller was lowered by crane 240 feet to the ground and hauled off for scrap.

On the other hand, Woodson, the building's chief engineer, is still in one piece and looking forward to starting up the two new Carrier 19XR centrifugal chillers that replaced their aged cousin.

"It's like saying good-bye to an old friend," Woodson said as he watched the 13,000-pound compressor section being lowered to the ground not long after the faint winter sun peeked over the ridge behind the bank building. "There was nothing wrong with it, but we figured it was time to replace it with something more efficient. The CFC-11 refrigerant was getting hard to come by and more expensive, too."

Scrapping the old Syracuse-built chiller wasn't an easy decision. There's some sense to the old saying: "If it ain't broke, don't fix it." The chiller still had all but five of its several hundred original copper heat exchanger tubes. The thrust bearing, a critical component that usually needs replacing long before a 33rd birthday, was original, too. A replacement bearing that had been included in the original purchase is still wrapped in oiled paper. The addition of electronic controls and several other options through the years had improved the chiller's efficiency, too.

Evergreen Chiller
 

Tender, loving care by Woodson and Carrier technician Allen Burchfield (a 25-year-veteran), also played a part in keeping the chiller purring according to Hugh Vaughn, president of Tower Associates, the building's owners.

"Barney and Allen have taken good care if it, but we knew we had seen other buildings that had replaced chillers 10 or 15 years younger than this one," Vaughn said. "You don't press your luck with tenant comfort. We knew the time would come, so Barney started doing his homework about three years ago."

The goal was to replace the 700-ton capacity chiller with two smaller, higher efficiency chillers that used non-ozone-depleting HFC-134a refrigerant. They also had to be capable of being lifted 240 feet to the top floor of the BB&T and slid sideways through an opening in a concrete block wall.

Jerry Saunders, a Carrier Building Systems and Services salesman based in Charlotte, N.C., introduced Woodson to Carrier's chlorine-free chillers when he brought him to visit the "Traveling Showcase," Carrier's mobile exhibit hall packed into an 18-wheeled tractor-trailer.

"I knew I wanted HFC-134a refrigerant after that," Woodson said. "And since we operate at part load a lot of the time up here in the mountains, we started thinking about two, smaller chillers rather than a single large machine. This way I will be able to operate one machine most of the time to lower our costs and still keep the tenants comfortable. There's another reason, too. When you've got only one chiller, it just can't fail. This way, I've got a back-up if I need it."

Saunders planted the seed and worked with Barney and Clint Canaday, a consulting engineer, to create a system that would be nearly twice as efficient as the chiller being replaced and reduce operating costs significantly. The sale also includes a five-year full maintenance agreement.

"I did some load estimates and Clint did his," says Woodson, "Then we worked some more with Carolina Power and Light to see what kind of break on electricity costs we could get by reducing our power consumption to a lower bracket. Then I made the presentation to the board."

Old Carrier 19C Centrifugal Chiller
 

The board of Tower Associates is headed by Glenn Wilcox, the BB&T building's majority owner. Despite his easy warm smile, the flint-hard businessman in Wilcox is close to the surface. He made it clear he expected the new chillers to perform even better than the old one had.

"We expect significant savings from these two machines and I'll be an unhappy camper if we don't get them," Wilcox said with his disarming smile. "I don't want to imply that savings were the only thing we were after, however.

"There was a real question about the future availability of the old refrigerant, and support from the manufacturer also was important. Barney had grown to count on that support over the years as we upgraded the old machine. We count on Barney and his guidance and he has a lot of faith in these machines."

Wilcox must have faith in them, too. He was up on the roof showing them off to his grandson like a teenager with a new car.

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