Industry sees huge potential for low-charge NH3 systems in the U.S.

By Elke Milner, Jul 14, 2015, 13:36 3 minute reading

Low-charge packaged ammonia systems are the hot new trend in refrigeration, offering a safer and less regulated opportunity than some traditional technologies, and because of their standard design, low charge systems are easier for technicians to understand and maintain.

Especially after the EPA’s January Enforcement Alert on preventing chemical accidents, in particular those relating to anhydrous ammonia in refrigeration facilities, low charge ammonia systems have gained keen interest at many industry conferences this year, including ATMOsphere America 2015. A key message from the Low-Charge Ammonia Panel is the necessity to work with regulators and electric utilities to drive the market
Wave of low-charge systems on the horizon
John Scherer, Manager of Engineering for Los Angeles Cold Storage, has developed a low-charge packaged ammonia refrigeration system that typically uses less than 50 pounds (23kg) of ammonia, or less than a pound per TR (ton of refrigeration). The system is now available under the NXTCOLD brand to other cold storage operators, and one of the systems has been installed at LA Cold Storage, cutting the ammonia charge by 1,000 pounds (454kg), and removed another 7,000 pounds (3175kg) through other means. A patented electronic refrigerant injection control mechanism senses the quality of the refrigerant in the evaporator and introduces only as much as necessary, maximising the evaporator coils’ heat transfer. 
So far the company has installed four units, but another 46 units will be placed by August, and within the next 10 months Scherer expects to have about 100 units in the field, including many retrofits. He believes the low-charge units are applicable to many other kinds of end users, from farmers to supermarkets.
Kurt Liebendorfer, Vice President, Evapco, asserted that the industry can expect a wave for low-charge ammonia packaged solutions coming in the next 18-24 months. Aside from cold-storage applications, low-charge packaged systems are also applicable to pharmaceutical and bioscience facilities. Evapco has invested heavily in research and development, boasting the only third-party low-temperature evaporator lab in the U.S., as well as manufacturing processes needed to turn out high volumes of low-cost product, in order to drive market adoption.
Working with regulators and electric utilities will drive market adoption
According to Gerard von Dohlen, President of Newark Refrigerated Warehouses, the future of refrigerated warehouses is the packaged low-charge ammonia system. New Jersey cold storage operators are now in a position to consider low-charge systems, thanks to von Dohlen and former IIAR president Bruce Badger, who negotiated an exemption to the old state law requiring engineers on premises 24 hours a day at facilities that use ammonia. Operators can be exempt from that requirement if they: 
  • use 5,200 pounds  (2360kg) of ammonia or less, 
  • run a system that is IIAR-2 compliant and 
  • employ one full-time engineer certified by RETA (Refrigerating Engineers & Technicians Association). 
Von Dohlen is actually planning to convert the Newark Refrigerated Warehouses facilities to low-charge systems himself, one DX and one using brine and air as secondary coolants.
Currently, low charge systems must comply with the same sea of regulations and codes as custom-designed systems with higher charges. Pega Hrnjak emphasised the industry needs to work together to open regulations in a direction that will support packaged systems and reduce requirements.
Electric utilities are increasingly recognising the value of natural refrigerant systems in saving energy and are thus rewarding end users with rebates that make the systems more affordable. Southern California Edison began studying the efficiency of low-charge ammonia systems years ago, initially estimating a 15-25% saving compared to HFC-based refrigeration, and a 5-10% saving compared to a large ammonia warehouse, as well as reduced peak demand. 
A more recent project at a Lineage Logistics cold storage warehouse in Oxnard, California, calculated a preliminary annual savings of 14% with a NXTCOLD low-charge unit. SCE is also evaluating an Evapco low-charge, low-water-consumption unit as well as a low-charge, air-cooled Azane system.


By Elke Milner

Jul 14, 2015, 13:36

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