16 



BULLETIN 98 ; U. S. DEPARTMENT OF AGRICULTURE. 

 Table IX. — Specific heat of brine with different percentages of salt. 



Per cent 

 of salt. 



Specific 

 heat of 

 brine. 



Per cent 

 of salt. 



Specific 

 heat of 

 brine. 







1 



5 



10 



1.000 

 .992 

 .960 

 .892 



15 

 20 

 25 



0.855 

 .829 

 .783 





















































































































































































































p»° 





























K 





























loo 



:> i 



; * 



f- t 



i, £ 



i ! 



O 1 



Z I 



4 1 



b 1 



3 £ 



o a 



2 2 



4 26 



Fig. 4, 



FEROHNTAtxE or SALT tr* MIXTURE. 



-Refrigeration available with different percentages of 

 salt. 



Usually salt when added to ice is of a higher temperature than 

 that of the ice; consequently the correction for its heat above 32° F. 



must be subtracted from 

 the available refrigeration 

 shown by the curve, figure 

 4; and if the brine is al- 

 lowed to escape at a tem- 

 perature below 32° F. the 

 refrigeration lost in the dis- 

 charge brine must be sub- 

 tracted, while, on the other 

 hand, if the discharge brine 

 is at a temperature higher 

 than 32° F. the correction 

 must be added. 



If given amounts of ice 

 and salt, at a temperature 

 of 32° F. are mixed together and the mixture supplied with suffi- 

 cient heat to melt the ice and dissolve the salt and raise the tem- 

 perature of the resulting brine to 

 the original temperature of 32° 

 F., then the total amount of heat 

 absorbed by the reaction will be 

 the sum of the latent heat of the 

 ice and the heat of solution of the 

 salt to form the resulting brine of 

 the density which will result from 

 the particular proportion of salt 

 and ice chosen. As an example, 

 under the foregoing conditions, 

 if 100 pounds of dry salt is 

 added to 900 pounds of ice the 

 total available refrigeration is 

 1,000 X 133 = 133,000 B. T. U. 

 The available refrigeration per 

 pound of mixture, 133 B. T. U., is taken from curve in figure 4. If 

 the salt added is at a higher temperature than 32° F., say 60° 



too 



















































ffS 



















































.90 



















































I 



< .85 



y 



















































S> 



















\ 









n 





















N 



S 





.75 























\ 





























.?c 





























3 







/ 



o 



/ 



5 



?- 



o 



Z 



s 





f=£-FtCe/VTACr£- Or SALT 



Fig. 5.— Specific heat of common salt brine, with 

 different percentages of salt. 



