FRUIT STORAGE 109 



possibility of the escape of ammonia in the cold storage 

 rooms. 



' ' Owing to the lower temperature and greater rapidity 

 of the circulation of the ammonia gas, only about two- 

 thirds the pipe surface is required to produce the same 

 effect as is necessary for brine circulation. 



"In the direct expansion system the refrigerating 

 effect ceases upon the stoppage of the compressor. In 

 small plants where this system is used it is not desired 

 to operate the machinery but a portion of each day. 

 One or more brine storage tanks can be placed in the 

 cold storage room, in which a portion of the expansion 

 coils are placed. The brine being cooled to a low tem- 

 perature while the machine is in operation, this body 

 of cold brine will help maintain the temperature during 

 the time the machine is shut down. "When brine storage 

 tanks are used, they are placed overhead in the room to 

 be cooled, when sufficient height permits, and arranged 

 so as to create a proper circulation of air. The cost 

 of installing a mechanical plant is much greater than for 

 an ice system, but after once installed, especially for 

 large houses, the operation would be much less. And 

 in most places it is considered the most economical sys- 

 tem to operate." 



Ventilation. All fruit storage houses need to be 

 constructed with a view to ventilation. This is neces- 

 sary: (1) To remove the gases given off by the various 

 products stored; (2) To remove the decay organisms 

 that occasionally appear in storage rooms; and (3) To 

 control, to some extent, the humidity required for the 

 best keeping condition of the fruit. In the case of 

 small "dug-outs" or storage cellars on the farm, little 



