MECHANICAL REFRIGERATION 83 



The strong-aqua tank is charged with aqua ammonia con- 

 taining 29 1/2 per cent of anhydrous ammonia. The ammonia is 

 pumped from the strong-ammonia tank to the generator, where 

 it is heated and the anhydrous ammonia distilled off. This 

 ammonia gas enters the condenser where it is condensed, and 

 from there it enters the ammonia receiver as liquid ammonia. 

 From the receiver, the ammonia is admitted through the ex- 

 pansion valve to the brine cooler, where it is again converted 

 into a gas, taking up heat from the brine. From the brine 

 cooler, the gas enters the absorber to be reabsorbed by the 

 water. The absorber and the generator are so connected that 

 the water in the generator, from which the anhydrous ammonia 

 has been distilled, is again transferred to the absorber and 

 thus the cycle is completed. 



The absorption system has not been adopted so generally as 

 the compression system, and is used for plants of large capacity 

 only. Plants of less than lo tons' capacity have not been con- 

 structed on the absorption system. 



