In a 1000-bin (800 pounds per bin) room held at 30-32°F 

 there are 800,000 pounds or 400 tons of apples. According to 

 "Modern Refrigeration and Air Conditioning" by Althouse, Turn- 

 quist and Braccinao, the heat of respiration of a ton of apples 

 at 32 F is 700 BTU's in 24 hours and 1/3 horsepower fan motors 

 give off 4250 BTU's per horsepower per hour. 



Assuming this room contains twelve fan motors, the heat 

 produced by the motors would be 408,000 BTU's in 24 hours while 

 the heat of respiration would be only 280,000 BTU's for the same 

 time period. There would be 1.45 times more heat produced by 

 the fan motors than by the heat of respiration from the apples. 

 There are other factors involved but this example illustrates 

 one of the major areas for energy cost savings. 



On-going research at the USDA Tree Fruit Research Laboratory 

 in Wenatchee, Washington includes monitoring and recording of 

 'Red and Golden Delicious' fruit temperatures during commerical 

 regular and CA apple storage rooms. The data collected over a 

 five year period showed: 



(1) once a room was loaded with bins of apples the air pattern 

 established at the time remained the same throughout the 

 storage season. 



(2) average fruit temperatures were maintained between 31-32 F 

 in cold rooms tested when the fans were run continuously 

 1/3, 1/2, and 2/3 of the time (by maintaining the fruit 

 temperatures, adjusting the cycling time to compensate 



for the physical conditions of the room, and maintaining 

 proper fruit temperatures, the most efficient cycle time 

 can be established) . 



(3) there was a fruit temperature gradient from the coldest 

 to the warmest sensored apple of 3-4 F; 



(4) in rooms where the coils were located above the bins, 

 with air being blown out over the bins and filtering down 

 through the fruit and bins and then pulled back through 

 the stacks of bins to the coils, the apples in the top 

 bins were the coldest; 



(5) the fans and refrigeration could be off up to 36 hours 

 before average fruit temperature rose 1 F (this could 

 vary depending upon the physical condition of the rooms) ; 



(6) data from fruit quality evaluation tests indicted no signi- 

 ficant difference was detected between apples held in 

 noncycled rooms over the cycled rooms (however, during 

 periods of extreme cold weather (0 to -10 F or colder) 

 for several weeks it would be a wise practice to run the 

 fans continuously to restore some of the heat being lost 

 from the room to the outside atmosphere. 



