Formulations for wax thermostatic element for effect in alternative temperature range Wax thermostatic elements are used automobile cooling systems and anti-scald mixing valves to control flow rates or to adjust mixing of flow inputs. These devices operate on the principle of thermal expansion of &quot;waxes&quot; to convert heat energy to mechanical energy (Wikipedia article).  A review of thermostatic mixing valves for sale indicates that the common formulation for the &quot;wax&quot; within the element in those devices expands in the range 20 °C to 50 °C.
Is it possible to formulate a &quot;wax&quot; that effectively changes volume in a lower temperature range such that it could operate a mixing valve, beginning at 5 °C, for instance, or are the materials typically used in this application not effective at temperatures below 20 °C?
Although typical applications for wax elements are centered around 40 °C, it is possible to create formulations for wax elements that change volume in the lower range of 5 °C to 20 °C.  The example below, although not linear in the lowest temperature extreme of the range of interest, behaves roughly linearly in the majority of the range.