CONFIDENTIAL REPORT 2G-21
S59
     
 
FORMER GERMAN SUBMARINE TYPE XXI
 
 
 
 
REFRIGERATION
  
     
 
SUMMARY
  
     
          A reasonably modern refrigeration system has been installed on the type XXI submarines, with a layout similar to that on U.S. submarines and the basic freon cycle the same as that used on earlier German types. One compressor is used to service all cooling facilities, i.e., the cold storage room, icebox and "potato" cool room.  The solenoid operated cutout valves used in the freon cycle are improvements over earlier German designs.  
     
     
     
     
     
     
     
 
April, 1946
 
 
 
 
PORTSMOUTH NAVAL SHIPYARD, PORTSMOUTH, N. H.
 
     
     
     
 
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  REPORT 2G-21
S59
     
 
REFRIGERATION
  
     
  1.  INTRODUCTION  
          The basic refrigerant cycle employed in the type XXI refrigeration system is given in Report 2G-9C-S59.  A brief description of the system used on the type XXI highlighting the changes from earlier types in individual design features will be given in this report.  
     
  2.  GENERAL DESCRIPTION  
          A line diagram of the refrigeration arrangement is given on Plate I.  The freon cutout switches are so interconnected that freon flow is either to the cold storage room or to the icebox and "potato" cool room.  As shown, individual thermostatically controlled expansion valves are used to control the temperatures of the individual rooms.  One of the two valves to the cold storage room is set for -18°C to -20°C and the other is set for +2°C to +4°C.   
          There are several changes in the system incorporated in the XXI over that existent in earlier German designs.  The cooling spaces are all adjacent, making it feasible to use the one large compressor rather than the small individual units.  However, the layout it such that mechanical selection for cooling of either cold storage or icebox and "potato" cool room is necessary.  The old bellows type of expansion valve has been replaced by the diaphragm type as used on present U.S. designs.  The freon cutout switches on the XXI were not used on earlier German types and provide a desirable automatic safety feature to the design.  
     
  3.  INDIVIDUAL COMPONENTS  
          1.  Compressor  
 
 
Compressor
Motor
Volts
110
170
RPM
220
270
1450
1780
Power Output
2.7 KW
Capacity
0.5 tons refrig.
Coil Temp.
-25°C
Condensing Water Temp.
+30°C
 
     
 
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  REPORT 2G-21
S59
     
          2.  Cooling Rooms  
 
  Cold Storage Potato Cool Room Icebox
Breadth 17 ft. 25 ft. 11.3 ft.
Height 18 18/6 5.6
Depth 20 23 21.0
Temp. -18° to 20°C +6° to +8°C +2° to +4°C
Capacity .17 tons .13 tons .08 tons
 
     
  4.  CONCLUSIONS  
          Although the refrigeration system on the XXI has several improvements over earlier German designs, it is standard in nature and has no particular features that are worthy of further discussion.  
     
     
     
     
     
     
     
     
     
     
     
 
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