APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 17 



F. ; then the available refrigeration will be 133,000 -[100X0.214 

 (60-32)] = 132,401 B. T. U., or 132.4 B. T. U. per pound of mix- 

 ture. If the resulting brine is allowed to escape at 25° F., the 

 available refrigeration is 133,000 -[1,000X0.892 (32-25)] = 126,756 

 B. T. U., or 126.7 B. T. U per pound of mixture. Or, in other words, 

 there is lost in the first case 100x0.214 (60-32) =599 B. T. U., and 

 in the second case, 1,000x0.892 (32-25) =6,244 B. T. U., or a total 

 loss, if the salt is added at 60° F. and the brine allowed to escape at 

 25° F., of 599 + 6,244 = 6,843 B. T. U. Under these conditions the 

 available refrigeration is 133,000-6,843 = 126,157 B. T. U., or 126 

 B. T. U. per pound of mixture. 



REFRIGERATION AS APPLIED TO MILK PLANTS, CREAMERIES. AND DAIRIES. 



The function of refrigerating apparatus, whether it is a refrigerating 

 machine or a bunker filled with ice, is to provide a heat-absorbing 

 medium which, after absorbing heat in the cold-storage room, may 

 be removed. After it has been removed from the coolers it may be 

 divested of its heat and allowed to return to the cooler for the pur- 

 pose of absorbing more heat, as is the case when some volatile liquid 

 is used, or it may be allowed to go to waste and a new supply 

 introduced, as in the case of cooling with ice. 



ICE BUNKERS. 



OVERHEAD BUNKERS. 



One of the simplest methods of cooling a cold-storage room is that 

 of an ice bunker, the principle of which is shown in figure 6 and 

 consists of a water-tight floor located over the compartments to be 

 cooled. The ice is piled on the floor through an opening at or near 

 the top of the room and the cooling is effected by the natural circu- 

 lation of air up and over the ice and down into the compartment in 

 which the goods to be cooled are stored. The movement of air is 

 naturally slow, as the power available is the difference between the 

 weights of the ascending column of warm air and the descending 

 column of cold air. As the air in contact with the ice is cooled it 

 flows down into the room below, where it comes in contact with the 

 warm goods in storage and absorbs heat from them, and as it becomes 

 warmer is forced up to the bunker, where it is gradually cooled, 

 thus producing a circulation. The movement of air may be increased 

 and lower temperatures obtained by employing a fan driven by an 

 outside source of power, or a mixture of salt and ice may be used in 

 the bunker, in which case a lower temperature may be obtained, 

 but in either case at the expense of a greater consumption of ice, 

 40083°— Bull. 98—14 2 



