46 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. 
order that the room may be cooled more quickly when the plaint is 
started after being shut down for several hours, the remaining 
one-third or two-thirds, as the case may be, being submerged in the 
solution of brine. 
Allowing a 3° rise in temperature of the air inside the room (32° 
to 35°) and a rise of calcium chlorid brine of 16° (6° to 22°), and 
as a cubic foot of brine will absorb about 52 B. T. U. per degree 
rise in temperature, the heat absorbed by the brine per cubic foot 
will be 52 (22-6) =832 B. T. U. The volume of brine necessary to 
hold over temperature under the foregoing conditions will then be 
34 400 
' 2 =41.3 cubic feet, or 1 cubic foot of brine for each 24.2 cubic 
feet of room space. In other words, the heat that will be absorbed 
by the 41.3 cubic feet of brine for a 16-degree rise will be 41.3 X 52 X 
16 = 34,362 B. T. U. Therefore, the hold-over period due to the brine 
34 362 X 16 
is — ' 400 — =16 hours. The 2,000 pounds of butter in storage will 
hold the temperature for 2.1 hours for a 3-degree rise in the room 
temperature. Consequently the total hold-over period due to both 
the brine and the butter will be 16+2. 1=18. 1 hours, or for a 16-hour 
shutdown the rise in room temperature will be 2.6°. During the 
hold-over period the average temperature difference between the 
air and the brine is about 19° F., and with a coefficient of heat trans- 
mission through the walls of the brine tanks of 1.5 B. T. U. per 
square foot per hour per degree difference in temperature of the 
brine and air, the effective square-foot surface of the tanks should not 
34 400 
be less than .. R ' - = 75 ; say two tanks 8 feet long, 1 foot 
id x iy x l.o 
wide, and 2\ feet deep. 
One linear foot of 1^-inch pipe when submerged in still brine will 
absorb about 4 B. T. U. per hour per degree difference in temperature 
between the inside and outside of pipe, and as this difference is 
about 13.5°, the amount of lj-inch submerged piping required is 
g viq g \y a =117 linear feet, or 58.5 feet per tank. 
o X lo.O X 4 
This method, however, is only a compromise between the brine- 
circulating and the direct-expansion systems, but has been found 
satisfactory and compares very favorably with the brine-circulating 
system of the same capacity. When used for holding over tempera- 
tures when the plant is shut down, either in case of breakdown of 
machinery or to avoid keeping an experienced attendant on duty 
continuously, the tank system for small plants possesses advantages 
over either the direct-expansion or brine-circulating systems. 
