Energy harvesting with fluids

An energy harvesting system comprising a rigid reservoir, a piston system, and a temperature range setting system, the energy harvesting system containing a fluid, said reservoir in fluid communication with:

• (a) the piston system that converts variations of the volume of said fluid into a mechanical motion, and
• (b) the temperature range setting system including at least a flexible chamber and a range setting mechanism, wherein the flexible chamber is connected to the range setting mechanism so as to engage motion of the piston system within a given temperature range, thereby managing the reactions of fluids to their environment changes in order to convert these reactions to harvest energy while protecting the device against destruction or malfunction when the environmental conditions exceed predefined thresholds, thereby automatically ensuring that energy conversion is efficient within the working temperature range and protecting the system against under/overpressure when outside the working temperature range.