APPLICATION OP REFRIGERATION TO HANDLING OF MILK. 77 
Em = temperature range of milk. 
0= capacity of compressor used for cooling milk. 
Hm = hours required for cooling milk. 
Kb = temperature range of brine. 
Taking the values in the case under consideration and substituting 
in the above formula and solving for the number of cubic feet of 
brine, we have : 
T (8,600X43) -(12,000X7.5X2) 011 ... 
1 = fi'n y 1 5 = 211 cubic leet 
During the 16-hour shutdown period the heat that will come 
through the walls, floor, and ceiling will be ' . * =84,224 
B. T. U., then 219.6 cubic feet of brine will absorb in rising 1 degree 
219.6X52 = 11,419 B. T. U., or the temperature of the brine will 
rise during the 16-hour shutdown period, disregarding the milk in 
84,224 ,_ , , 
storage, n 419 = 7 - 4 degrees. 
A cubic foot of milk in rising 1 degree will absorb about 61 B. T. U. 
Therefore the milk in storage, disregarding the brine, would rise 
, 84,224 1ft K , 
7 8 052 degrees. 
Considering both the brine and milk, a cubic foot will absorb 
132X61+219.6X52 
132 + 219.6 
= 55.4 B.T.U., and the rise in temperature will 
84 224 
be ., ' — =^-j =4.3 degrees during the 16-hour shutdown period, 
ool.b X oo.4 
Had the refrigerating machine been of sufficient capacity to have 
cooled the milk through the required range of temperature in the 
two hours it took to pasteurize, the size of the machine necessary 
351 310 X 24 
would have been ' nnr . =14.6 tons. A machine of this size 
Z X ZoOjUUU 
would, therefore, be idle most of the time, and as the initial cost of the 
larger machine and equipment would be a great deal more than the 
smaller one, it would be poor economy to install the larger machine. 
When either the "flash" or "holder" process of pasteurization is 
employed, the temperature of the milk is generally first lowered to 
approximately 75° F. by water from the city mains or from wells; con- 
sequently the refrigerating machine has only to lower the tempera- 
ture of the milk from the temperature at which it leaves the water 
section of the cooler to the temperature attained in the storage room. 
RAW-MILK PLANTS. 
In raw-milk plants it is only necessary to cool the milk from the 
temperature at which it is received, say 60° F., to a final tempera- 
ture of approximately 32° F. It is usually pumped directly from the 
