Heat exchanger

A system comprising:

• a turbine mechanically coupled to a generator and a compressor;
• and
• a heat exchanger fluidically coupled to the turbine and the compressor, the heat exchanger comprising:
• a shell configured to house a plurality of tubes and defining an exhaust fluid flow path within a first volume enclosed by the shell, the shell including an exhaust fluid inlet at a first end of the exhaust fluid flow path and an exhaust fluid outlet at a second end of the exhaust fluid flow path, wherein an outer surface of the plurality of tubes are in fluid communication with the flow path;
• a cap configured to be attached to a first end of the shell and defining a second volume, the cap including a source fluid inlet at a first end of a source fluid flow path and a source fluid outlet at a second end of the source fluid flow path;
• and
• a header configured to separate the first volume and the second volume, the header defining a tube inlet position and a tube outlet position of each of the plurality of tubes, wherein the tube inlets of the plurality of tubes are in fluid communication with the source fluid inlet and the tube outlets of the plurality of tubes are in fluid communication with the source fluid outlet, wherein the header is configured to flex with thermal expansion,
• wherein each of the plurality of tubes are substantially U-shaped including a U-bend and define a flow path of the source fluid within the exhaust fluid flow path,
• wherein the header comprises:
• a first cross-sectional area including the plurality of tube inlets;
• and
• a second cross-sectional area including the plurality of tube outlets, wherein the header is configured to reduce thermal conduction between the first cross-sectional area and the second cross-sectional area,
• wherein the first cross-sectional area and the second-cross-sectional area are separated by a cross-sectional area having a thickness in a longitudinal direction that is less than a thickness in the longitudinal direction of both the first cross-sectional area and the second cross-sectional area.

A method comprising:

• receiving a source fluid at a source fluid inlet of a heat exchanger;
• receiving an exhaust fluid at an exhaust fluid inlet of the heat exchanger;
• heating, via a heat exchanger, the source fluid via transfer of heat from the exhaust fluid, wherein the heat exchanger comprises:
• a shell configured to house a plurality of tubes and defining an exhaust fluid flow path within a first volume enclosed by the shell, the shell including an exhaust fluid inlet at a first end of the exhaust fluid flow path and an exhaust fluid outlet at a second end of the exhaust fluid flow path, wherein an outer surface of the plurality of tubes are in fluid communication with the flow path;
• a cap configured to be attached to a first end of the shell and defining a second volume, the cap including a source fluid inlet at a first end of a source fluid flow path and a source fluid outlet at a second end of the source fluid flow path;
• and
• a header configured to separate the first volume and the second volume, the header defining a tube inlet position and a tube outlet position of each of the plurality of tubes, wherein the tube inlets of the plurality of tubes are in fluid communication with the source fluid inlet and the tube outlets of the plurality of tubes are in fluid communication with the source fluid outlet, wherein the header is configured to flex with thermal expansion and reduce stress within the header and on the plurality of tubes,
• wherein each of the plurality of tubes have an outer diameter of 1 mm or less and are configured to have a spacing between respective outer diameters of adjacent tubes of 0.5 mm or less,
• wherein the header comprises:
• a first cross-sectional area including the plurality of tube inlets;
• and
• a second cross-sectional area including the plurality of tube outlets, wherein the header is configured to reduce thermal conduction between the first cross-sectional area and the second cross-sectional area,
• wherein the first cross-sectional area and the second-cross-sectional area are separated by a cross-sectional area having a thickness in a longitudinal direction that is less than a thickness in the longitudinal direction of both the first cross-sectional area and the second cross-sectional area.