Cryocooler Configuration Variations Available
The CryoTel family of cryocoolers has several options to assist you in meeting your requirements.
Many cryocooler applications require the load to be in a vacuum. To accommodate this Sunpower offers a vacuum flange option. The standard is an NW50 flange. Sunpower can also integrate a custom flange to meet your requirements. Sunpower offers permanent and removable NW50 flange options.
CT cooler with no vacuum flange
CT cooler with NW50 flange (and water jacket)
Heat rejection options
The cryocooler operates by moving heat from the cold finger region to the heat rejecter region. This heat must then be removed from the cryocooler to prevent the cryocooler from overheating and getting damaged. The most common cause of cryocooler returns is overheating. The customer must always cool the cryocooler to prevent damage. The drawing below shows the heat rejection region where this heat is removed from the cryocooler.
The two standard ways to accomplish this are via airfins or via a water jacket.
Water Jacket Option
The air fins are mounted to the heat rejecter. Heat is transferred from the heat rejecter to the fins, where forced air absorbs it and removes it from the system. In order to use the air fin option, your design must not allow for a gap > 1 mm between the air fins and the shroud. This will ensure that the air will go through the fins instead of the air gap. The minimum airflow required to maintain proper cooling is 100cfm. Sunpower offers permanent and removable air fins.
The water jacket is placed over the heat rejection area and water is forced through the water jacket system. The standard connector is a ¼” Swagelok compression fitting. Both the airfin and the water jacket are available as removable or permanent options.
For some applications, the customer has utilized conductive cooling to reject heat. The amount of heat rejection needs to equal the input power delivered to the controller, so at maximum power the MT needs 80 Watts, the CT 160 Watts, and the GT needs 240 Watts. The customer must be careful in the design of the system to guarantee the conductive heat rejection will meet the requirements otherwise the cryocooler will be damaged.
The cryocooler has internal components that oscillate at 60Hz for the cryocooler to function properly. There are several options to reduce this vibration.
The standard option is a passive balancer, also referred to as a passive absorber. This device is tuned to oscillate at 60Hz and absorb energy at this frequency. The passive balancer will have an amplitude of 3.0 mm for a MT, 3.5 mm for a CT and 5 mm for a GT.
Pressure Vessel Cooling
Sunpower offers a pressure vessel cooling jacket that slips over the back end of the cooler and attaches to a water jacket. The net effect is reduced temperature at the back end which results in improved cryocooler performance.