Abstract: This invention relates to a thermal energy device for receiving and storing externally applied thermal energy. The thermal energy device includes a thermal energy receiver which is adapted to receive the intermittent externally applied thermal energy to heat and expand a fluid in the thermal energy receiver. A thermal energy store is in fluid communication with the thermal energy receiver to receive and store the heated and expanded fluid received from the thermal energy receiver. The thermal energy store is responsive to the receiving and storing of the heated and expanded fluid such that, as the heated and expanded fluid is received and stored, the thermal energy store delivers more of the fluid to the thermal energy receiver to continue accommodating the intermittent externally applied thermal energy.