Packaged systems for industrial applications are being designed with a small charge of ammonia compared to that of traditional stick-built systems. Will these low-charge packaged systems rely less on ammonia sensors than traditional, large-charge systems do?
“I was concerned about it at first, but then I realized after seeing low-charge packaged systems in California and the number of sensors running that our [sensor] business was not going to be affected,” said Andy Neptune, sales manager for Calibration Technologies Inc. (CTI), a Columbia-Mo.-based maker of refrigerant sensor devices.
In fact, he added, “there’s the potential that we will see more – and we have been seeing more – sensor counts in small-charge systems. So, for us, I think it will be a good thing.”
He noted that the International Institute of Ammonia Refrigeration’s IIAR-2 standard for safe design of closed-circuit ammonia refrigeration systems calls for the use of sensors among other safety elements in packaged systems, which must be built in the same manner as central systems.
Low-charge systems use sensors in the low-range of detection, zero to 100 ppm or 250 ppm, Neptune said. The highest concentration observable in a major leak is calculated using the volume of the package, charge size and leak rate. The minimum detectable leak would be at 25 ppm.
In the event of leaks in low-charge-ammonia systems, recharging can usually be done quickly with a small amount of reserve ammonia, he noted. “You’re going to be up and running, with your temperature where it needs to be.”
CTI also sells CO<sub>2</sub> sensors for transcritical and cascade systems. The company’ s sensors were on display in June at the Global Cold Chain Expo in Chicago.
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