A Design Guide to Cooling Cordwood Modules for Vacuum Environments

The cordwood module has been a part of the electronic Packaging concept for approximately ten years [1]. During that time period all variety of parts have been packaged in this configuration with varying degrees of success and reliability. With the coming of the space age and vacuum environments becoming commonplace, the removal of ´heat has become progressively more difficult with higher packaging densities ,and more´ sophisticated piece parts. This paper describes methods utilized in the removal of heat from cordwood modules, arid takes some of the difficulty out of predicting thermal gradients.of piece parts within these modules. Fundamentally, the method is predicated on the use of the equivalent of Ohm´s law. and the ability to realistically utilize proper piece part´ thermal resistances. Design data and guidelines are presented that allows ´one to achieve designs for minimum weight, maximum thermal efficiency, and high reli- abil´ity.