A thermal storage composition is defined by a polymer having thermally responsive absorption or passage capabilities based on an Upper Critical Solution Temperature (UCST) or Lower Critical Solution Temperature (LCST), and a sorbent in fluidic communication with the polymer. A fluid such as water conveys thermal energy between the polymer and the sorbent based on an identified target temperature that acts as a thermostat for synergistic fluid release and transfer between the polymer and sorbent that stores and releases heat energy in a cyclic manner. The composition includes a synergistic integration of a sorbent and selectively hydrophilic polymer to alternately hydrate according to a target temperature based on the UCST of the water/sorbent combination.