NOVELTY - The system has a pump (150) maintaining level of liquid-phase working fluid within a fluid vessel (110). The pump displaces liquid-phase working fluid through a liquid-phase supply line (134a) to an indoor heat exchanger (121) and maintains the fluid within a portion of a return line (135) in liquid phase in an energy capture mode. The pump cycles the fluid between a reservoir (180) and the vessel to minimize stagnation within the vessel in an energy release mode, while vapor-phase working fluid is passively displaced through a vapor-phase supply line (134b) to an outdoor heat exchanger (122).    USE - System for generating a ground-based thermal battery utilized to heat and cool a structure on a ground in a geothermal heat exchange field. Uses include but are not limited to a house, garage, commercial building, skyscraper, docked boat or ship, agricultural generator field e.g. crops/cattle field, sport arena and a gymnasium area on a land area, water body, soil, dirt, rock and earth.    ADVANTAGE - The system is designed such that the return line can be pressurized to reduce and eliminate vaporization of the fluid in the heat exchangers and a fluid routing system. The fluid vessel containing the failed component can be removed, while remainder of the fluid vessel remains in the ground if a component of the fluid vessel malfunctions or fails, thus reducing maintenance costs and improving longevity of the system over time. The system extends growing season and reduces damage to crops due to temperature fluctuations, with docked ships to provide temperature regulation without continuous operation of a large diesel engine in the cattle field to warm water troughs for cattle during the winter or beside a nuclear or solar power plant for storage of waste heat. The pump is preferably arranged proximal bottom of the fluid vessel such that the pump pushes the fluid out of the fluid vessel to reduce vapor lock immobilizing the system. The reservoir functions as an external flow-through vessel when the pump cycles the fluid from the bottom of the fluid vessel to the top of the fluid vessel to reduce depth-dependent temperature gradient in the ground and to reduce potential for system stagnation and to increase volume of heat transfer between the working fluid and the ground. The working fluid within the fluid routing system remains in the liquid phase in the energy capture mode, so that the portion of the fluid routing system can be pressurized to prevent vaporization of the working fluid. The pump cycles the liquid-state working fluid between the reservoir and the fluid vessel to prevent stagnation within the system.    DETAILED DESCRIPTION - The working fluid is water or R-134a refrigerant. INDEPENDENT CLAIMS are also included for the following:    (1) a system for storing ambient heat in a ground-based thermal hot battery    (2) a thermo siphon vessel comprising an integration cap.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a thermo siphon vessel and a system for storing seasonal environment energy.    System for storing seasonal environment energy (100)    Fluid vessel (110)    Indoor heat exchanger (121)    Outdoor heat exchanger (122)    Liquid-phase supply line (134a)    Vapor-phase supply line (134b)    Return line (135)    Pump (150)    Reservoir (180)