COLD STORAGE FOR APPLES AND PEARS 



37 



Precooling 



Precooling is usually spoken of as a special process for the rapid 

 removal of heat from a commodity before transportation. The term 

 is used also in some fruit districts to denote rapid heat removal pre- 

 liminary to stacking in storage or even as a cooling prior to packing. 

 The principles of rapid heat removal are the same regardless of sub- 

 sequent disposal of the fruit. 



Probably the most effective present method of precooling is to stack 

 the fruit in relatively small rooms in which a large volume of cold 

 air is circulated. The advantage of the small room is that cooling 

 need not begin until after all the warm fruit has been brought into it. 

 The additional expense of many small rooms usually demands an 

 adaptation of the principle of dividing the storage into several rooms 

 of moderate size. In large plants it is desirable to have more than one 

 brine-spray chamber, so that temperatures in one part of the storage 

 in which fruit is being held at optimum storage temperatures may not 



Figure 10. — Efficient arrangement of packing house, 20 x 166 feet, and cold 

 storage, 50 x 166 feet, with refrigerated basement, designed for a medium-sized 

 orchard: A, Outside compressor room, 16 x 28 feet; B, brine-spray and fan 

 room; C, air lock to save refrigeration from open outside doors; D, fruit 

 conveyor system ; E, package-lidding press ; F, ports for receiving or delivering 

 fruit ; G, outside doors. 



be influenced by the temperatures being used in the precooling rooms. 

 Having air ducts of ample size, with a system of main dampers so 

 that the volume of air to a given room may be governed according to 

 its demands for refrigeration, is an important feature of design. It 

 permits the diversion of refrigeration from well-cooled rooms to a 

 room being filled with warm fruit. 



For efficient precooling, it is necessary that the rooms be so designed 

 that the cold air will have a positive flow between the stacked packages. 

 The more rapid the circulation and the colder the air, the faster the 

 heat will be removed from the body of each package. For these rea- 

 sons the circulation system should be planned for the free movement 

 of air in large volume through the fruit packages, rather than having 

 it dispersed about the room from circuitous ducts and from small duct 

 openings that tend greatly to restrict the air flow and to prevent it from 

 having the fullest sweep over the surface of the packages. 



