An electrochemical system that can serve as a heat engine or heat pump is disclosed. The electrochemical system comprises a first electrode assembly, a second electrode assembly, a first electrolyte and a second electrolyte. The first electrode assembly, configured to operate at a first temperature, includes a first electrode set and a second electrode set. The second electrode assembly, configured to operate at a second temperature different from the first temperature, includes a first electrode set and a second electrode set. The first electrolyte is configured to circulate between the first electrode set of the first electrode assembly and the first electrode set of the second electrode assembly. The second electrolyte is configured to circulate between the second electrode set of the first electrode assembly and the second electrode set of the second electrode assembly.