Alternative temperature chamber designs based on recirculating cooler technology

Conventional temperature chambers rely upon heat convection to transition product across a temperature range. Several are used at Textron Systems. In general, these chambers are costly, have a large footprint, and are incompatible with temperature sensitive test equipment, such as CCD cameras and optical detectors. An alternative heat conduction technology, based upon a recirculating cooler, should be considered when cost, size or temperature sensitivity of test equipment is a concern. Compared to a conventional temperature chamber, a recirculating cooler based design may reduce the system cost and size by a factor of two or more. Additionally, a recirculating cooler based design provides thermal isolation for test equipment that's not in contact with the device under test (DUT). This paper discusses two different recirculating cooler temperature chamber designs. Detailed calculations are given for the first design, which is operational. Highlights are given for the second design, a system that's under construction.