FARM STORAGES FOR APPLES 29 



Cost of Refrigerated Storage 



A refrigerated storage will cost from 50 cents to $1.00 a bushel, depending upon 

 whether it is developed from an existing structure or built new. Large units 

 converted from abandoned buildings have been provided at initial costs as low 

 as 50 cents a bushel. Frame structures insulated with fill insulation have been 

 built new for initial costs of less than 75 cents a bushel. 



The annual cost of operating a refrigerated storage is m.ade up of interest and 

 depreciation on the building and machinery, taxes, in.surance, repairs, and power. 

 The power consumption naturally depends upon the length of the storage season, 

 the temperature at which the storage is carried, and the effectiveness of the in- 

 sulation. As a rough estimate, it can be assumed that the current consumption 

 will be from 1 to l}4 kilowatt-hours per bushel stored. The annual cost in a 

 20,000-bushel storage valued at $15,000 will be about 12 cents a bushel if filled to 

 capacit\-. Inasmuch as overhead (interest, depreciation, taxes, insurance) is a 

 fixed charge and remains constant whether the storage is full or only partially 

 filled, the annual cost per bushel will increase as the ratio of bushels stored to full 

 capacity decreases. If the storage is only half filled, the cost will increase to 

 about 19 to 20 cents a bushel. These figures are based on electric power at 3 

 cents a kilowatt-hour. 



Care of Refrigeration Equipment 



Refrigerating units are sufficiently complex so that actual repairs of the ma- 

 chines have to be made by qualified mechanics. There are, however, certain pre- 

 cautions and observations which should be made by the operator to insure proper 

 functioning of the system, even though actual adjustments may have to be made 

 by a service man. When a plant is installed, the installing engineer usually 

 instructs the owner (juite fulK in its operation. Frequently, however, the in- 

 structions are not as complete as desired and at times do not cover changes which 

 occur with continued operation. When a new man is employed, it is highly 

 desirable that he be properly instructed in the care of the equipment. 



There are certain difficulties that maj develop in the operation of the refrig- 

 eration equipment which the operator should be able to recognize. Some of 

 these he may be able to correct, while for others he must call a service man. The 

 following is a partial list of conditions which may require attention. 



Low Suction Pressure 



The operator should know the [proper suction pressure for his plant at different 

 room temperatures. The suction pressure varies with the type of refrigerant 

 used, the temperature of the storage, the relative size of evaporating unit to size 

 of compressor, the amount of refrigerant in the system, and the amount of frost 

 on the coils. Where two or more evaporating units are connected to one com- 

 pressor, the suction pressure will vary with the number of units which are operat- 

 ing at any one time. If, however, the suction pressure falls off gradually over a 

 long period of time, it may be because of leaks and loss of refrigerant. It is 

 usually necessary to employ a service man to recharge the system. If the pressure 

 drops considerably within a short period of time, the trouble may be due to 

 e.^ccessive frost on the coils. The operator should have specific directions for 

 defrosting the units, as the procedure differs with different plants. 



Low suction pressure may be due to the fact that an insufficient amount of 

 refrigerant is admitted to the evaporating coils. Enough refrigerant should be 



