A single stage thermoelectric assembly is limited to the maximum delta T of an individual module assembly. In those applications which require higher delta-Ts the modules can be cascaded. Cascading is the mechanical stacking of thermoelectric modules into stages so that the cold side of one stage becomes the heat sink of a smaller stage on top. This adds the delta-T of one stage upon another. In addition to the heat pumped by any given stage, the next lower stage must also pump the heat resulting from the input power to that upper stage. Consequently, each succeeding stage must be larger, from the top of the cascade downward.
TECA no longer manufactures the small, highly specialized cascades that were once used in defense and communications. Today the focus is on larger, ultra-low temperature benchtop cooling systems used by today’s researchers and scientists. Shown below are an isometric drawing of the LHP-1200C31 three stage cascade and a pictorial/graphical representation of a 3 stage cascade.