Sunpower Inc. CryoTel
MT Operating Instructions version 4
14
Figure 11: Water Jacket Heat Rejection
B. Copper Fins
Copper fins are also available in a permanent or removable form. If copper fins are used for
heat rejection (Fig. 12-permanent fins are pictured), use a fan with a rating of 100 cubic feet
per minute (1.6e-3 m
3
/min) for air through-flow. Sunpower recommends mounting the fan to a
cylindrical shroud that can be placed around the fins in order to direct the air through the fins.
Note that some heat rejection also occurs from the walls of the pressure vessel. Therefore avoid
permitting any containment structure for the cryocooler to hinder the heat rejection from any
part of the cooler. It is also recommended to electrically interlock the cooling fan and the
controller in order to ensure that the cooler cannot operate without also turning on the fan. For
additional cost, Sunpower is able to provide a fan, shroud, and controller that are suitable for
laboratory testing.
Figure 12: Cooling Fin Heat Rejection
C. Conducting Solid
Use of any other means of heat rejection necessitates ensuring that the proper amount of heat is
being transferred away from the rejector and that the reject temperature is suitable. It is
recommended to involve Sunpower with the design of a conduction heat exchanger.
