One of the most important concepts in designing a superior energy saving ultra-low freezer is how efficiently heat is exchanged between the high and low stage circuits. By providing optimum heat exchange pathways in the design, it not only increases efficiency of the system, leading to greater energy savings, but it will also have an effect of reducing stress on the compressors, leading to greater overall system reliability. PHCbi’s new capillary tube heat exchanger is but the latest step in increasing the available heat exchange areas in the system. This patent pending innovation significantly increases the efficiency of the entire system. The end result is less energy consumption, while improving the overall efficiency of the freezer.