Abstract: A thermal energy system includes a solar energy collector, a ground loop having an inlet and an outlet, and a heat pump. A first fluid conduit extends from the outlet to the solar energy collector, and from the solar energy collector to the inlet, for transporting a heat exchange fluid, from the outlet to the inlet through the solar energy collector. A second fluid conduit extends from the outlet to the heat pump, and from the heat pump to the inlet, for transporting the heat exchange fluid, from the outlet to the inlet through the heat pump. A fluid pump is provide for urging the fluid to flow from the inlet to the outlet through the ground loop, and from the outlet to the inlet through at least one of the first and second conduits. Control valves and a controller may be provided to automatically select a fluid flow mode from a number of selectable modes.