System and apparatus for energy conversion

An energy conversion system, comprising:

• a closed cycle engine comprising a regenerator having a regenerator body, a piston assembly comprising a first piston, a first piston body defining a first piston chamber, a second piston, and a second piston body defining a second piston chamber, the first piston disposed within the first piston chamber, the second piston disposed within the second piston chamber;
• wherein the closed cycle engine is oriented along a lateral axis, wherein the first piston body defines a first distal portion of the closed cycle engine and the second piston body defines a second distal portion of the closed cycle engine, the first distal portion and the second distal portion disposed at opposite regions of the lateral axis;
• and
• wherein the closed cycle engine comprises at least one of:
• a first plurality of working-fluid pathways providing fluid communication between the first piston chamber at the first piston body and the second piston chamber at the second piston body;
• or
• a second plurality of working-fluid pathways providing fluid communication between the second piston chamber at the second piston body and the first piston chamber at the first piston body;
• and
• wherein the first plurality of working-fluid pathways and/or the second plurality of working-fluid pathways include:
• i) a plurality of hot-side working fluid pathways providing fluid communication between a plurality of first piston chamber apertures of the first piston chamber containing the first piston and a plurality of regenerator apertures of the regenerator body of the regenerator;
• and ii) a plurality of cold-side working fluid pathways providing fluid communication between a second plurality of regenerator apertures of the regenerator body and a plurality of second piston chamber apertures of the second piston chamber containing the second piston,
• wherein the regenerator body defines a hot-side portion comprising a hot-side regenerator conduit and a hot-side plurality of fin arrays adjacently disposed within the hot-side regenerator conduit and a cold-side portion comprising a cold-side regenerator conduit and a cold-side plurality of fin arrays adjacently disposed within the cold-side regenerator conduit, the hot-side regenerator conduit and the hot-side plurality of fin arrays being longitudinally separated from the cold-side regenerator conduit and the cold-side plurality of fin arrays by a hot-to-cold gap to provide at least two thermally distinct thermal storage bodies within the regenerator body, the hot-to-cold gap being larger than gaps between individual fin arrays in each of the hot-side plurality of fin arrays and the cold-side plurality of fin arrays.