Evapco ejector ammonia
Kurt Liebendorfer of Evapco with the new Ejet evaporator system at the IIAR 2024 conference

Evapco’s New Ejector System for Low-Charge Ammonia ‘the Best of Both Worlds’

The Ejet system offers liquid recirculation performance and DX system design, operation and technology, the company says.

U.S. manufacturer Evapco has developed an Ejet-branded evaporator for its low-charge ammonia (R717) packaged refrigeration units that uses an ejector to raise the capacity and efficiency of a DX (direct exchange) evaporator almost to the level of a pumped liquid recirculation unit while offering the low charge and stable operation of a direct expansion (DX) system, the company says.

The new technology was showcased with Evapco’s VersaSplit system at the IIAR 2024 Natural Refrigeration Conference & Heavy Equipment Expo, held March 24-27 in Orlando, Florida.

Last October, Evapco launched VersaSplit, a condensing unit that the company deems the “world’s first” packaged low-charge ammonia mega-split industrial refrigeration system, with up to six remote DX evaporators operating at different temperatures.

The Ejet system “combines the best of both worlds – liquid recirculation performance and DX system design, operation and technology,” said Beth Fox, Evaporator Product Manager for Evapco, in a presentation at the IIAR 2024 conference, adding, “Evapco is the first to apply an ammonia vapor ejector for an industrial refrigeration application.”

The Ejet system contains an ejector that recirculates liquid refrigerant that would otherwise need to be vaporized using superheat to prevent carryover into the compressor. “With Ejet, you can run superheat lower and make the DX evaporator more like a recirculation evaporator, capturing liquid out of the coil that isn’t used and putting it back into the evaporator,” explained Kurt Liebendorfer, Vice President, Business Development, Industrial Refrigeration for Evapco, at the IIAR conference. The lowering of superheat improves the efficiency of the evaporator, he added.

Currently, the Ejet system is used only for medium-temperature applications 35°F (1.7°C) and higher. For low temperature, Eject needs a “different design that has not been perfected yet but it’s coming,” said Liebendorfer.

From recirculation to DX

Evapco’s low-charge penthouse refrigeration units were originally designed to use pumped liquid recirculation but at a very low 1.2 to 1 recirculation rate. But as evaporators in the VersaSplit system are at a distance from the condensing unit, Evapco preferred to use the high-pressure liquid of DX rather than a pump, said Liebendorfer. “It’s easier with high-pressure liquid.”  The DX system also keeps the charge at a low 5lbs/TR (0.65kg/kW).

In the Ejet system, an ammonia liquid-gas mixtures passes through the expansion valve into an inlet separator, which sends the liquid into the distributor and then to the evaporation coil. The suction header captures excess liquid refrigerant before it escapes to the compressor rack, and then the ejector uses the ammonia flash gas from the inlet separator to pull the liquid back to the distributor and coil, delivering almost 1.2 to 1 recirculation rate in a traditional DX system.

Evapco's Ejet
Design of Evapco’s Ejet system at the IIAR 2024 conference

“You are 95% of your circulated rating with this [Ejet] operation, and compared to traditional DX it is lower in dollars per ton,” said Cory Groves, Product Application & Marketing Manager, Industrial Refrigeration for Evapco. Fox said the capacity of the Ejet system is 15–30% greater than a DX system and 95% of a recirculated system.

The Ejet design enables the system to use only two or three degrees of superheat rather than seven to 10, said Groves. “So you can shrink the size of the evaporator to be more like a recirculation size than a DX.” And by enabling evaporation throughout the coil, the Ejet offers “more capacity and lower fan horsepower,” he added.

The first installation of the VersaSplit system took place at a cold-storage facility in Reno, Nevada, with 10 two-evaporator VersaSplit units.  Now a VersaSplit can support six independent evaporators, which has made it very economical compared to Evapco’s penthouse unit that contains two evaporators, noted Liebendorfer. The company secured three new VersaSplit projects in January and February, two cold-storage facilities and one food processor, he added.

In 2022, Evapco announced its acquisition of Canadian-based manufacturer Systèmes LMP (known generally as LMP) to form subsidiary Evapco Systems LMP, combining Evapco’s expertise in ammonia refrigeration with LMP’s in transcritical CO2 (R744) refrigeration in the North American marketplace.

“You are 95% of your circulated rating with this [Ejet] operation, and compared to traditional DX it is lower in dollars per ton.”

– Cory Groves, Product Application & Marketing Manager, Industrial Refrigeration for Evapco

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