The chiller, incorporating a microchannel condenser, is designed for building air-conditioning and process cooling, noted Troy Davis, Energy Group Manager for Mayekawa USA, in an interview at IIAR 2022. It is also suitable for commercial refrigeration applications.
At its IIAR booth, Mayekawa USA exhibited the largest version of the chiller, which offers a capacity of 76TR (267.3kW) at 86°F (30°F) ambient using 50 lbs (22.7kg) of ammonia. Two other models offer capacities of 58 and 38TR (204 and 133.6kW), with 39 and 26lbs (17.7 and 11.8kg) of ammonia, respectively. With an average charge of 0.66lbs/TR (0.09kg/Kw), they produce outlet/inlet chilled water of 44 and 54°F (6.7 and 12.2°C), respectively.
The air-cooled chillers are being produced in Brazil in order to cut costs and “make them more competitive with HFC/HFO chillers,” said Davis. One model is earmarked for installation at a food processor in Los Angeles, California, he added.
The air-cooled chiller design was originally tested at a plant in Berkeley, California, in a project sponsored by the California Energy Commission (CEC) and the Electric Power Research Institute (EPRI).
Davis acknowledged that ammonia chillers are “not common” in the U.S., where chillers using f-gases such as R32, R410A, R134a and R448A are prevalent. “Not everyone is into ammonia; it’s not for downtown San Francisco,” he said.
On the other hand, he added, “over the last couple of years, a lot of engineers are asking for it because it’s a natural refrigerant and is highly efficient, and because of TFA [trifluoroacetic acid] concerns.” Air-cooled chillers are installed outside, reducing concerns about ammonia leaks.
“There’s a lot more knowledge about natural refrigerants,” said Davis. “It took 10 years, but they are finally aware, and [the market] is changing quickly.”
Other manufacturers offering low-charge ammonia chillers include Evapco, Azane, Frick (Johnson Controls) and M&M Carnot; Evapco debuted a low-capacity version of its air-cooled low-charge ammonia chiller at IIAR 2022.
Larger-capacity water-cooled chillers
The introduction of Mayekawa’s air-cooled ammonia chiller follows on the heels of the company’s exhibition of its FUGU mCHILLER low-charge water-cooled ammonia chillers for the first time in the U.S. at the AHR Expo, held in Las Vegas, Nevada from January 31 to February 2.
Mayekawa USA introduced the FUGU chillers to the U.S. market late last year after extensive factory testing and 20 installations in Europe, said Davis. “It was developed by our Mayekawa Nordic [Denmark] Team for the European market to compete against standard HFC and HFO chillers at a good cost point and [as a] complete unit, ready to go,” said Davis. The FUGU units can use water or adiabatic cooling.
The FUGU chillers are also designed for process cooling and building air-conditioning, but at higher capacities than those offered by the air-cooled chillers. At water temperatures (outlet/inlet) of 44.6/53.6°F (7/12°C), the FUGU’s capacities range from 192 to 378TR (675.2kW to 1,318.8kW), with ammonia charges of 122lbs to 176lbs (55.3 to 79.8kg), respectively. The largest unit has a charge/capacity ratio of 0.47lbs/TR (.06kg/kW).
To date, Davis said he has several FUGU units quoted for wineries, breweries, food processing and some larger district cooling/campus projects, but no installations in the U.S. yet.
“Over the last couple of years, a lot of engineers are asking for [ammonia] because it’s a natural refrigerant and is highly efficient.”Troy Davis, Mayekawa USA
Want to find out more, or have something to say about this story? Join the ATMO Connect network to meet and engage with like-minded stakeholders in the clean cooling and natural refrigerant arena.