FRUIT STORAGE 103 



down and then by passing through the storage room take 

 up the heat given off by the fruit. In such an arrange- 

 ment, it is necessary to have two independent coils of 

 pipes. The one that comes in contact with the ice and 

 in which the cooling down is done is known as the 

 primary coil, and the one that circulates through the 

 storage room as the secondary coil. 



The principle of this circulation is just the reverse of 

 the hot water system for heating buildings. The primary 

 coil is the one highest up and as the brine in the circu- 

 latory system is cooled down it becomes heavier and 

 settles to the bottom. As it circulates through the stor- 

 age room it absorbs the heat from the room and expand- 

 ing becomes lighter and rises again, until it reaches the 

 primary coil. In this way a constant flow of the liquid 

 through the pipes keeps the air in the storage room at 

 the desired temperature without the bad effect of the 

 moisture-ladened air coming into direct contact with 

 the fruit itself. In most of these types of storage houses, 

 the ice is harvested during the winter and stored in an 

 annex to the regular plant. Then from this supply the 

 ice is crushed as needed, elevated to the tank enclosing 

 the primary coils, and fed in as desired. 



If the natural melting of the ice does not keep the 

 temperature sufficiently low, salt is added to hasten the 

 melting, the theory of the whole operation being that 

 the ice in melting takes up the heat by absorption from 

 the primary coil, thus cooling down the brine inside. 

 The addition of the salt to the crushed ice only increases 

 the rapidity of the melting ; hence, increasing the absorb- 

 ing power of beat from the surrounding atmosphere. 

 Therefore, the more rapidly the ice melts the more rap- 



