A spiral heat exchanger includes a spiral unit, a case member, and a bracket. The spiral unit includes thin metal plates. The thin metal plates are spaced away from each other and spirally wound. The thin metal plates define flow paths. A portion or all of the flow paths are provided with a coolant flowing therein. The case member is attached to a vehicle and contains the spiral unit. The bracket is fixed to the case member and holds the spiral unit. The bracket includes a holding portion and a fixed portion. The holding portion holds a first end, a second end, or both of the spiral unit in an axial direction. The fixed portion is disposed between an outer peripheral surface of the spiral unit and an inner peripheral surface of the case member. The fixed portion is fixed to the inner peripheral surface of the case member.

An energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly, that includes a first heater body and a first engine body. The first heater body may define a first portion of a first monolithic body or at least a portion of a first monolithic body-segment. The first engine body may define a second portion of the first monolithic body or at least a portion of a second monolithic body-segment operably coupled or operably couplable to the first heater body. The engine assembly may include a second heater body and/or a second engine body. The second heater body may define a portion of a second monolithic body or a third monolithic body-segment. The second engine body may define a portion of the second monolithic body or a fourth monolithic body-segment operably coupled or operably couplable to the second heater body and/or the first engine body.

An energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly, that includes a first heater body and a first engine body. The first heater body may define a first portion of a first monolithic body or at least a portion of a first monolithic body-segment. The first engine body may define a second portion of the first monolithic body or at least a portion of a second monolithic body-segment operably coupled or operably couplable to the first heater body. The engine assembly may include a second heater body and/or a second engine body. The second heater body may define a portion of a second monolithic body or a third monolithic body-segment. The second engine body may define a portion of the second monolithic body or a fourth monolithic body-segment operably coupled or operably couplable to the second heater body and/or the first engine body.

A heat exchange flow path portion is formed by alternately winding two spirally-shaped first and second heat transfer walls, with a predetermined gap interposed therebetween in the radial direction of the flow path pipe, around the outer periphery of a cylindrical flow path pipe, in which a cooling heat source is disposed in a main heat transfer flow path inside thereof. An inlet flow path and an outlet flow path for introducing compressed air into the flow path pipe and discharging compressed air from the flow path pipe are alternately formed, in the radial direction, from the gap between the heat transfer walls. Heat exchange is performed between compressed air that flows in the flow path and compressed air that flows in the flow path.

A monolithic combustor body may provide multi-stage combustion. A combustor body may include a combustion chamber body and a plurality of heating walls that include a heat sink. The combustion chamber body may be disposed annularly about a longitudinal axis and defining a combustion chamber. The plurality of heating walls may include heat sink. The plurality of heating walls may occupy a radially or concentrically outward position relative to the combustion chamber and may define a corresponding plurality of combustion-gas pathways fluidly communicating with at least a proximal portion of the combustion chamber. During operation, the combustor body may exhibit multi-stage combustion that includes a first combustion zone occupying a distal or medial position of the combustion chamber relative to the longitudinal axis, and a second combustion zone occupying a proximal position relative to the first combustion zone and a radially or concentrically outward position of the combustion chamber and/or a radially or concentrically inward position of the plurality of combustion-gas pathways.

A monolithic combustor body may provide multi-stage combustion. A combustor body may include a combustion chamber body and a plurality of heating walls that include a heat sink. The combustion chamber body may be disposed annularly about a longitudinal axis and defining a combustion chamber. The plurality of heating walls may include heat sink. The plurality of heating walls may occupy a radially or concentrically outward position relative to the combustion chamber and may define a corresponding plurality of combustion-gas pathways fluidly communicating with at least a proximal portion of the combustion chamber. During operation, the combustor body may exhibit multi-stage combustion that includes a first combustion zone occupying a distal or medial position of the combustion chamber relative to the longitudinal axis, and a second combustion zone occupying a proximal position relative to the first combustion zone and a radially or concentrically outward position of the combustion chamber and/or a radially or concentrically inward position of the plurality of combustion-gas pathways.

A heat transport device comprises first flow passages through which a first fluid flows, and second flow passages through which a second fluid flows, wherein a cross-section A satisfying the following Requirement 1 to Requirement 3 can be achieved. Requirement 1 is that the cross-section A is a cross-section perpendicular to the second flow passages. Requirement 2 is that in the cross-section A, the holes of second flow passages are separated by meandering partition plates and are disposed in a layered manner. Two adjacent partition plates are a partition plate B and a partition plate C, and when comparing a point α, which is the top point of a mountain in the partition plate B closest to the partition plate C, and a point β, which is the bottom point of a valley in the partition plate C closest to the partition plate B, the point α is closer to the partition plate C side than the point β. Requirement 3 is that the first flow passages are present inside the partition plates.

A heat transport device comprises first flow passages through which a first fluid flows, and second flow passages through which a second fluid flows, wherein a cross-section A satisfying the following Requirement 1 to Requirement 3 can be achieved. Requirement 1 is that the cross-section A is a cross-section perpendicular to the second flow passages. Requirement 2 is that in the cross-section A, the holes of second flow passages are separated by meandering partition plates and are disposed in a layered manner. Two adjacent partition plates are a partition plate B and a partition plate C, and when comparing a point α, which is the top point of a mountain in the partition plate B closest to the partition plate C, and a point β, which is the bottom point of a valley in the partition plate C closest to the partition plate B, the point α is closer to the partition plate C side than the point β. Requirement 3 is that the first flow passages are present inside the partition plates.

A heat transport device comprises first flow passages through which a first fluid flows, and second flow passages through which a second fluid flows, wherein a cross-section A satisfying the following Requirement 1 to Requirement 3 can be achieved. Requirement 1 is that the cross-section A is a cross-section perpendicular to the second flow passages. Requirement 2 is that the holes of the second flow passages are disposed so as to be aligned in the left-right direction and to form layers in the up-down direction; and when comparing layers with holes adjacent in the up-down direction, the holes of the second flow passages are not disposed at the same position in the left-right direction. Requirement 3 is that the first flow passages exist between the layers with holes adjacent in the up-down direction, and the first flow passages meander in the up-down direction so as to avoid the holes of the second flow passages in the layers with holes that are sandwiched in the up-down direction.

A constant density heat exchanger is provided. The constant density heat exchanger includes a housing extending between a first end and a second end and defining a chamber having an inlet and an outlet. A first flow control device is positioned at the inlet of the chamber and movable between an open position in which a working fluid is permitted into the chamber and a closed position in which the working fluid is prevented from entering the chamber. A second flow control device is positioned at the outlet of the chamber and movable between an open position in which the working fluid is permitted to exit the chamber and a closed position in which the working fluid is prevented from exiting the chamber. A heat exchange fluid imparts thermal energy to the volume of working fluid held at constant density within the chamber by the first and second control devices.