Ammonia absorption type utilities

Refrigerant temperatures greater than 32°F suggest the steam jet or lithium bromide absorption system. Between 30°F and —40°F, the ammonia-water absorption or a mechanical compression system is indicated. At less than —40°F, a mechanical compression is used, except in special desiccant situations. The economics of temperature level selection will depend on utility (steam, power) costs at the point of installation and the type of pay-out required, because in some tonnage ranges, the various systems are competitive based on first costs. 

Absorption is also utilized to collect vapors and gases. In this process, the contaminated airstream is fed to a scrubber or packed tower containing a liquid which will dissolve or chemically react with the contaminant. Because of its low toxicity and its ability to dissolve many materials, water is often used for this purpose. Often, water-soluble gases such as ammonia and hydrogen chloride are collected in this type of cleaning system. The resulting solutions from these operations must ultimately be disposed of responsibly. 

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