APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 59 



Suppose the ice required to cool a certain size box during the hot- 

 test weather is 500 pounds per 24 hours. The refrigeration accom- 

 plished by this amount of ice melting is .500X144 = 72,000 B. T. U. 

 Assuming that the conditions existing in the plant will justify the 

 operation of the ma- 



chine eight hours 

 per day, then the 

 capacity of the ma- 

 chine must be suffi- 

 cient to extract 

 72,000 B. T. U. in 

 eight hours, or in 

 one- third of the 

 time that it takes 

 to melt the ice. 

 Therefore the capac- 

 ity of the refriger- 

 ating machine must 

 72,000X3 



mMMmmmmmm 



2'Af.P.S.CORK 



/ AIR SPACE 



be 



0.75 



''* BOARPS, P. r/tf. 

 YS.RPAPEA 

 &'mPSCORK. 



Z"tt.&S.CORK 

 /'A Iff SPACE 



BOAKOS, O.tPZriKRP/IPEA 



% BOARD,0.1M.+W.R PAPEtt 

 S'ft.PS.CORK. 

 _ I" AIR SPACE 



■ ^ J* 7&ae>AR'>SD.*rf.<n*.p>PAi'ert 



' 7 /o BOARPS, t>. *M. tHCPPAPER 

 -t'/V/NCKAL WOOL. 



\eoAKes,p.tn «fwra 

 3- fyeoARos.irrpiYMP'fHPEn 



S'sKAHVLATee CORK 



[2.ZO 

 |SJ*to Cua.Fr 



^-JfrBOARPS. VHP* WltPAPER. 

 *^Y Y&BOARDS,l>l*M.*W.RPAPEP. 



/"air space 



"^■ j - && BOARDS. P.+M.+VtRPAPEA. 



4-"&RArtULATEP CORK 



g ■ fcj - Z a BOARPS.O.+IH.*IKB PAPER 

 Z'AtPt SPAGC 

 TqBOARPS.P.*M. *I*.P. PAPER 



% BOARD. P. ^Pt fW. P PACER 



US 



t'AIR SPACE j 



~^S SCARPS. P.tAt.*KP PAPfKJ 



Fig. 26. — B. T. U. transmitted per square foot per 24 hours per 

 degree difference in temperature. 



288,000 

 ton. Usually lower 

 temperatures than 

 can be maintained 

 by the use of ice are 

 desired, consequent- 

 ly a l-ton machine, 

 although slightly 

 larger than the re- 

 quirements, should 

 be installed. 



In figure 29 (p. 62) are given the maximum and average tempera- 

 tures for the different States. 



APPROXIMATE COST OF PRODUCING MECHANICAL REFRIGERATION IN 



SMALL PLANTS. 



The cost of producing a ton of refrigeration mechanically depends 

 upon so many variables, especially in small plants, that it is impos- 

 sible to give more than approximate costs. The average plant used 

 in creameries and diaries is operated about eight hours daily during 

 the summer months when the work required of the refrigeration 

 machinery is at its maximum. Then the total time of operation dimin- 

 ishes until the machine is shut down entirely or run very little during 

 the winter months. 



