A FreeTherm thermal energy storage system includes an ice-water shallow pool used for storing and extracting thermal energy cyclically, by thawing the ice and freezing water intra-seasonally. A series of heat extractors positioned within the shallow pool are adapted to extract heat during the formation of ice. Bladders are connected to the heat extractors and also connected to a conventional heat pump and have an anti-freeze mix that is maintained at sub-freezing temperatures flowing through their interiors to remove heat from the heat extractors. The extractors have concave-downward surfaces for extracting heat from water to produce ice. The heat extractors are made of flexible material that can be expanded to release ice from their surfaces, and are adapted to pivot up and out of the way to allow the released ice to float to the top of the reservoir. During the summer cooling cycle, convection assisted insulated tower and program of upward airflow is used to deliver heat from a thermal reservoir of water through a heat exchanger to relatively cooler outdoor air. The heat exchanger is used to refresh the thermal reservoir with cool water during periods when the outdoor air is substantially cooler than the water in the reservoir.