Circular no. 740 



February 1946 • Washington, D. C. 



UNITED STATES DEPARTMENT OF AGRICULTURE 



Cold Storage for Apples and Pears 



By W. V. Hukill, senior agricultural engineer, Division of Farm Buildings and 

 Rural Housing, and Edwin Smith, senior horticulturist, Division of Fruit and 

 Vegetable Crops and Diseases, Bureau of Plant Industry, Soils, and Agricultural 

 Engineering, Agricultural Research Administration 



CONTENTS 



Use of cold storage for fruit 



Response of fruit to storage con- 

 ditions 



Respiration and ripening 



processes 



Storage temperatures 



Humidity 



Air circulation and ventila- 

 tion 



Controlled-atmosph :re, or 



gas, storage 



Storage sanitation 



Storage behavior of apples and 



pears 



Apples 



Pears 



Cold-storage plants and equip- 

 ment 



Refrigeration 



Cold-storage rooms 



Required capacity of a refrig- 

 eration system 



Page 

 2 



6 

 6 



7 



7 



13 



15 

 15 

 23 



30 



Cold-storage plants and equip- 

 ment — Continued. 



Calculating refrigeration re- 

 quirements 



Cold-storage design 



Precooling 



Capacity and height of 



rooms 



Lay-out of rooms 



Fans and ducts 



Girders and joists 



Slotted floors 



Handling equipment 



Planning for economy 



Safety 



Cold-storage management and 



plant operation 



Handling the fruit 



Control of the plant 



Operating efficiency 



Literature cited 



LIST OF TABLES 



1. Average freezing temperature 



of various fruits 



2. Capacity and power data for 



typical 2-cylinder ammonia 

 compressors 



3. Relation of coil-room tempera- 



tures to relative humidity 

 in storage room 



4. Data on sodium chloride 



(common salt) and calcium 

 chloride brines 



5. Approximate refrigeration re- 



quired for apples if 1,000 

 boxes are received daily and 

 the fruit is cooled to 32° F. 

 in 7 days 



669297° — 46 1 



Page 



22 



23 



25 



32 



6. Heat-insulation values of va- 



rious materials in dry con- 

 dition 



7. Space required for standard 



apple packages 



8. Relative humidity (percent) 



of atmosphere by wet- and 

 dry-bulb thermometers 



9. Relation of head or condens- 



ing and suction pressures 

 to horsepower requirements 

 per ton for typical ammonia 



compressors 



10. Temperatures of liquid ammo- 

 nia at various gage pres- 

 sures 



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48 

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 60 



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