﻿REFRIGERATION OF DRESSED POULTRY IN TRANSIT. 



17 



The indices of efficiency obtained by the use of the foregoing 

 formula have served as a basis on which to compare cars of different 

 construction. They are not claimed to be an accurate expression 

 of the resistance of the car to heat transmission nor of its exact 

 capacity for utilizing the refrigerant supplied. To obtain figures 

 mathematically and physically exact would necessitate the record- 

 ing of the amount of ice and salt used during the period of observa- 

 tion and other data not readily secured from cars in commercial 

 service. It is highly desirable that such accurate figures should be 

 obtained, and it is hoped that the information which this report is 

 able to furnish may lead to the compilation and utilization of such 

 data. 



COMPARISON OF CAR EFFICIENCY. 



The magnitude of the field of operation covered by this investi- 

 gation and the complexity of the factors uniting to determine the 

 efficiency of the refrig- 

 erated carrier made it 

 highly desirable that 

 some concrete expres- 

 sion be worked out 

 whereby a comparison 

 of the various types of 

 cars studied might be 

 made. 



The application of 

 the formula to the 

 cars used in the ex- 

 perimental shipments 

 results in a wide dif- 

 ference of efficiency 

 indices (see Table 5) 

 for the various types 

 of cars. All of the 

 cars of type A are 

 identical in original construction and are operated by a single 

 company. The cars of type B are alike in ice bunkers and insula- 

 tion, but, belonging to a different series, they vary in size. The 

 cars of type C are all of the same dimension; likewise those of type D. 

 Each type is operated by one railroad or car company. The four 

 types are unlike each other in many of the essential elements of 

 refrigerator construction, such as the kind and thickness of insu- 

 lation, its manner of application, ice bunkers, and doors. For the 

 sake of a clearer understanding, the efficiency indices of Table 5 are 

 presented graphically as figure 4, in which the height of the columns 

 increases directly as the efficiency. 

 7078°— Bull. 17—13 3 



Fig. 4. — Comparative efficiency of cars of types A, B, C, and D. 



