Constant density heat exchanger and system for energy conversion

A constant density heat exchanger, comprising:

• a housing extending between a first end and a second end and defining a plurality of chambers that are circumferentially arranged;
• a first plate positioned at the first end of the housing, the first plate defining a first port;
• a second plate positioned at the second end of the housing, the second plate defining a second port aligned with the first port;
• and
• a controller configured to:
• cause the first plate and the second plate to rotate in unison about an axis of rotation relative to the housing so that the first port and the second port sequentially align with the plurality of chambers one after another, and
• wherein, when the first port and the second port align with a given one of the plurality of chambers, the first port and the second port simultaneously align respectively with an inlet and an outlet of the given one of the plurality of chambers to allow a first volume of working fluid to enter into the given one of the plurality of chambers through the first port and a second volume of working fluid heated at constant density to exit the given one of the plurality of chambers through the second port.