ACHRNEWS

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May 15, 2000
A catastrophic flooding of a 1,200-ton chiller posed a serious problem for the 5,000-plus inhabitants of a large office tower in New Jersey. Last summer’s heat wave made working without air conditioning an impossibility.

Acting quickly, building management immediately called their service contractor, Monsen Engineering.

“The number-one priority was to arrange for a rental chiller,” said Jeff Somers, service operations manager. “While that was being handled, our engineers and technicians assessed the damage and started to develop a plan.

“The rental chiller was onsite and operating the next afternoon.”

Ruptured tubes

The damage, it turned out, was worse than anticipated. After draining 2,000 gal of water from the chiller, Monsen technicians discovered that nearly 200 tubes had frozen and ruptured.

“Considering the amount of moisture and amount of damage, we were looking at months of dehydration using vacuum pumps and dry ice,” said Somers. “That would cost the client a fortune in manhours, not to mention chiller rental.”

Monsen decided to look for alternatives.

After some discussion, the contractor called one of its subcontractors. “Hudson Technologies specializes in catastrophic refrigerant-side services,” said Somers. “We had used them before and thought they might have a cost-effective solution.”

The first thing Hudson did was to send a service team to recover the charge. All that remained of 5,000 lb of R-134a was 184 lb.

Then the company’s engineering team worked with Monsen’s team to develop a plan. A list of action items was put together for Monsen that would be completed prior to Hudson performing dehydration.

While Monsen plugged leaks and prepared the chiller, Hudson engineers had time to fine-tune their dehydration strategy.

“Dehydration is never easy,” said Joe DeMaio, the company’s regional sales manager. “Because of the capillary effect, moisture becomes trapped in pockets throughout a chiller. And each make and model of chiller is a unique dehydration challenge.”

The reclaim company, however, has a successful track record. In its lab there is an open-drive, single-stage centrifugal system and a hermetic, multistage centrifugal chiller.

“We’ve flooded these systems and experimented with different techniques,” said Joe Longo, vice president of engineering. “We’ve put a lot of research into chiller dehydration.”

Three-month job done in two weeks

When Monsen had prepared the chiller for dehydration, Hudson technicians Frank Hall and Jim Ward arrived with a fully equipped refrigerant-side service vehicle.

With them they brought the tools needed to dehydrate this 1,200-ton chiller: the ZugiBeast™ high-speed refrigerant decontamination system, a predetermined quantity of service refrigerant, and online monitoring instruments. The time goal: two weeks.

Monsen technicians conducted simultaneous eddy current tests as dehydration proceeded on the chiller to ensure there were no more tube leaks.

When the dehydration was complete two weeks to the day after Hudson arrived on site, the company’s two techs recharged the system, then used a portable lab to analyze the refrigerant for moisture content.

“It came up 25 ppm” said Somers. “I would have been happy to sign off if it came up 50 ppm, and the ARI allows levels up to 100 ppm.”

Mission accomplished.