In 2017, Wako Chemicals, a U.S.-based manufacturer of biochemicals, embarked on an expansion of its production facilities, and as a result, its old R22 chiller became insufficient. This prompted the company to choose a low-charge ammonia chiller solution from Evapco to handle the increased production needs and provide redundancy.
The chosen solution has a higher capacity, but is more compact than the old R22 system and fits into the same space. It also has an almost 18% higher coefficient of performance (COP) than an alternative R404 solution.
Wako Chemicals, a subsidiary of FujiFilm, manufactures bio- and organic chemicals, antibodies and enzymes.
“We needed to increase cooling capacity and provide a level of redundancy; in addition to that, we needed extremely stable cooling capacity,” said Daniel Frye, Plant Purchasing Supervisor at Wako, in a case study presented by Kurt Liebendorfer, Vice President of Evapco, provider of the low-charge system. (The case study was presented at the online ATMOsphere America 2020 conference, organized by shecco, publisher of Ammonia21.com.)
The plant, located in Richmond, Virginia, needed “a nominal 67.5 tons (237.4kW) of cooling from a 5°F (-15°C), 50% ethylene glycol solution, with occasional higher peak loading,” according to Evapco Vice President Kurt Liebendorfer.
The plant’s senior management originally sought an f-gas replacement to its system, but “we saw an opportunity to specify a natural refrigerant,” said Chris Newman, Partner at Midatlantic Refrigeration, the contractor that carried out the project. “Given the need for 5°F process fluid temperatures, we considered the possibility of installing an ammonia-based system.”
After an evaluation of the options, management chose the ammonia option. “The clear advantages of the Evapcold LCR-C low-charge ammonia chiller became evident,” Newman said. The COP of the Evapco ammonia solution was 2.49, whereas the alternative R404a solution had a lower COP at 2.14. This amounts to a 17.8% difference. The LCR-C units were shipped to the customer in April 2018.
An Easy Fit
The two LCR-C ammonia chiller units fit “easily” into the space of the older and smaller R22 system, according to Liebendorfer. The system can provide 406 gallons/minute of recirculated condenser water, which enters the cooling tower at 95°F (35°C) and returns to the chillers at 85°F (29.4°C). The refrigerant charge is 80lbs (36.3kg) per unit, for a total of 160lbs (72.6kg). With a total capacity of 135TR (475kW), it gives a low charge of 1.18lbs per TR.
The two units are “almost entirely” redundant, with one unit running constantly, and coming on for an hour a day during the warmest summer days.
The final installation and commissioning was handled by ColonialWebb, a Richmond, Virginia-based contractor. “The chiller systems were piped to two existing pump skids and [a] hot well-cold well tank without requiring much rework,” said Andy Brogan, Sales Engineer at ColonialWebb.
The units were installed in a building away from the main facility, saving space in the main facility and ensuring all service and maintenance procedures are separated from processing or refrigerated spaces. It also eliminates ammonia from the main facility.
Commissioning happened in August 2018. In the first two years of operation, the only equipment failure has been a glycol valve that became inoperable and had to be replaced.
“This was the first Evapcold system I’ve worked on,” Brogan added. “I wish more plants would go this direction for their refrigeration needs. These units are user friendly, easily maintained, and based on the quality of construction, they’ll last a long time.”
The satisfaction also extends to the end user. “Wako has been more than satisfied with the new system,” said Brogan.
“I wish more plants would go this direction for their refrigeration needs. These units are user friendly, easily maintained, and based on the quality of construction, they’ll last a long time,”Andy Brogan, ColonialWebb
Evapco ammonia chillers
The packaged low-charge LCR-C ammonia chillers from Evapco have a wide variety of configuration options, resulting in over 200 models. They have capacity from 20TR (70.3kW) to 400TR (1,407kW), and are capable of producing chilled fluids from 5°F to 50°F (-15 to 10°C).
They use variable speed screw compressors, for efficient capacity control and part-load operation. The units are also plug-and-play — arriving fully wired, piped and insulated. They are equipped with starters and a single-point 460V electrical connection.
Some of the optional accessories include fluid pumps, waste heat recovery, outdoor enclosure housing and multiple servicing options. Component suppliers include Bitzer, Danfoss WEG, RVS pressure vessels, and plate and frame heat exchangers from Kelvion Plate & Frame.
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