Ultra-low temperature freezer cabinet utilizing vacuum insulated panels

1. Field of the Invention An ultra-low temperature refrigeration system () comprising a housing () and a door () which together define an interior storage compartment (). The system () uses multiple layers () of varying insulative materials to insulate the housing (), including conventional foam () and vacuum insulation panels (), to balance cost, size, and capacity considerations. The vacuum insulation panels () are provided with beveled edges () or otherwise positively interfacing edges so as to overlap adjacent panels and present a more reliably insulative seam. The system () further includes a self-defrosting pressure equalization port () for automatically equalizing interior and exterior pressures.