Abstract: An apparatus for fabricating an internally finned pressure vessel includes a plurality of positioning discs, each of the positioning discs defining a plurality of circumferentially spaced slots extending radially into the positioning disc from a perimeter thereof, and one or more rods extending through the plurality of positioning discs, the plurality of positioning discs being held in axial alignment by the one or more rods. A method of fabricating the internally finned pressure vessel includes providing the apparatus, loading a plurality of fins into the slots of the positioning discs, inserting the apparatus containing the plurality of fins into a pressure vessel, attaching the plurality of fins to the pressure vessel by a brazing process, and removing the apparatus from the pressure vessel.

Abstract: A method of electricity production using water thermal energy includes compressing an enclosed working fluid at a first vertical position relative to a surface of a body of water to cause the fluid to move to a second vertical position relative to the surface and subsequently move to the first position in a closed loop, an external environment at the second position having a greater temperature than an external environment at the first position such that the fluid transitions between a liquid phase at the first position and a vapor phase at the second position, the compressing using power from a battery, and expanding the fluid at the second position to generate electricity to charge the battery. The first and second positions may be two depths of the body of water or a height of an atmosphere above the body of water and a depth of the body of water.

Abstract: A method of electricity production using water thermal energy includes compressing an enclosed working fluid at a first vertical position relative to a surface of a body of water to cause the fluid to move to a second vertical position relative to the surface and subsequently move to the first position in a closed loop, an external environment at the second position having a greater temperature than an external environment at the first position such that the fluid transitions between a liquid phase at the first position and a vapor phase at the second position, the compressing using power from a battery, and expanding the fluid at the second position to generate electricity to charge the battery. The first and second positions may be two depths of the body of water or a height of an atmosphere above the body of water and a depth of the body of water.