Abstract: Implantable medical systems enter an exposure mode of operation, either manually via a down linked programming instruction or by automatic detection by the implantable system of exposure to a magnetic disturbance. A controller then determines the appropriate exposure mode by considering various pieces of information including the device type including whether the device has defibrillation capability, pre-exposure mode of therapy including which chambers have been paced, and pre-exposure cardiac activity that is either intrinsic or paced rates. Additional considerations may include determining whether a sensed rate during the exposure mode is physiologic or artificially produced by the magnetic disturbance. When the sensed rate is physiologic, then the controller uses the sensed rate to trigger pacing and otherwise uses asynchronous pacing at a fixed rate.

Abstract: A heat exchanger that includes first and second headers, a first flow conduit fluidly connecting the first and second headers to allow for a flow of a first fluid through the heat exchanger, the first flow conduit being bounded by a first generally planar wall section extending between the first and second headers, a second flow conduit to allow for a flow of the second fluid through the heat exchanger, the second flow conduit being bounded by a second generally planar wall section spaced apart from the first generally planar wall section to define a gap therebetween, and a thermally conductive structure arranged within the gap and joined to the first and second generally planar wall sections to transfer heat therebetween. The thermally conductive structure is isolated from the first fluid by the first generally planar wall section and from the second fluid by the second generally planar wall section.

Abstract: A power generation system having a combustion engine with a Rankine bottoming cycle, the system including a first flow path for a process fluid and a second flow path for a working fluid, and a heat exchanger arranged along both the first and the second flow paths to transfer waste heat from the process fluid to the working fluid. The heat exchanger includes a first flow conduit being bounded by a first wall section and configured to convey the process fluid, a second flow conduit to convey the working fluid, the second flow conduit being bounded by a second wall section spaced apart from the first wall section to define a gap therebetween, and a thermally conductive structure arranged within the gap and joined to the first and second wall sections to transfer heat therebetween, the gap being fluidly isolated from both the process fluid and the working fluid.

Abstract: A heat exchanger and a method are provided to vaporize a working fluid using a heat sourcing fluid. The heat exchanger includes a first section, a second section, and a third section. A first portion of the heat sourcing fluid passes through the first section, in counter-flow with the working fluid. A second portion of the heat sourcing fluid passes through the second section, in co-flow with the working fluid. Both the first and second portions pass through the third section, in overall counter-flow with the working fluid. The working fluid passes sequentially through the third section, the first section, and the second section. The heat exchanger and/or the method may be used in a Rankine cycle for waste heat recovery or in a refrigerant cycle.

Abstract: A fuel cell system includes a plurality of fuel cells arranged into a stack. A combustor receives a cathode exhaust flow from the fuel cell cathodes and a flow of fuel. The fuel is oxidized in the combustor by the cathode exhaust to produce a mixed exhaust flow. A cathode air flow path extends between a fresh air source and the fuel cell cathodes. An air preheater is arranged along the cathode air flow path, cathode air passing through the air preheater being heated therein by a flow of uncombusted anode exhaust from the fuel cell anodes. A cathode recuperator is arranged along the cathode air flow path, cathode air passing through the cathode recuperator being heated therein by the mixed exhaust flow. Water passing through a vaporizer is converted to steam by heat from the mixed exhaust flow and directed from the vaporizer to the fuel cell anodes.

Abstract: A power generation system having a combustion engine with a Rankine bottoming cycle, the system including a first flow path for a process fluid and a second flow path for a working fluid, and a heat exchanger arranged along both the first and the second flow paths to transfer waste heat from the process fluid to the working fluid. The heat exchanger includes a first flow conduit being bounded by a first wall section and configured to convey the process fluid, a second flow conduit to convey the working fluid, the second flow conduit being bounded by a second wall section spaced apart from the first wall section to define a gap therebetween, and a thermally conductive structure arranged within the gap and joined to the first and second wall sections to transfer heat therebetween, the gap being fluidly isolated from both the process fluid and the working fluid.

Abstract: A heat exchanger that includes first and second headers, a first flow conduit fluidly connecting the first and second headers to allow for a flow of a first fluid through the heat exchanger, the first flow conduit being bounded by a first generally planar wall section extending between the first and second headers, a second flow conduit to allow for a flow of the second fluid through the heat exchanger, the second flow conduit being bounded by a second generally planar wall section spaced apart from the first generally planar wall section to define a gap therebetween, and a thermally conductive structure arranged within the gap and joined to the first and second generally planar wall sections to transfer heat therebetween. The thermally conductive structure is isolated from the first fluid by the first generally planar wall section and from the second fluid by the second generally planar wall section.

Abstract: A fuel cell system includes a plurality of fuel cells arranged into a stack. A combustor receives a cathode exhaust flow from the fuel cell cathodes and a flow of fuel. The fuel is oxidized in the combustor by the cathode exhaust to produce a mixed exhaust flow. A cathode air flow path extends between a fresh air source and the fuel cell cathodes. An air preheater is arranged along the cathode air flow path, cathode air passing through the air preheater being heated therein by a flow of uncombusted anode exhaust from the fuel cell anodes. A cathode recuperator is arranged along the cathode air flow path, cathode air passing through the cathode recuperator being heated therein by the mixed exhaust flow. Water passing through a vaporizer is converted to steam by heat from the mixed exhaust flow and directed from the vaporizer to the fuel cell anodes.

Abstract: A fuel cell system (1) is provided and includes a fuel cell stack (3), a cathode recuperator heat exchanger (33) adapted to heat an air inlet stream using heat from a fuel cell stack cathode exhaust stream, and an air preheater heat exchanger (39) which is adapted to heat the air inlet stream using heat from a fuel cell stack anode exhaust stream.

Abstract: A heat exchanger and a method are provided to vaporize a working fluid using a heat sourcing fluid. The heat exchanger includes a first section, a second section, and a third section. A first portion of the heat sourcing fluid passes through the first section, in counter-flow with the working fluid. A second portion of the heat sourcing fluid passes through the second section, in co-flow with the working fluid. Both the first and second portions pass through the third section, in overall counter-flow with the working fluid. The working fluid passes sequentially through the third section, the first section, and the second section. The heat exchanger and/or the method may be used in a Rankine cycle for waste heat recovery or in a refrigerant cycle.

Abstract: An integrated fuel cell unit (10) includes an annular array (12) of fuel cell stacks (14), an annular cathode recuperator (20), an annular anode recuperator (22), a reformer (24), and an anode exhaust cooler (26), all integrated within a common housing structure (28).

Abstract: A vaporizing heat exchanger (10, 68) is provided for vaporizing a fluid flow using a thermal energy containing flow. Flow paths (24, 26, 28) for each of the fluid flow and the thermal energy containing flow are located relative to each other such that the fluid flow makes multiple passes wherein the fluid is vaporized and subsequently superheated.

Abstract: A fuel cell unit includes a plurality of angularly spaced fuel cell stacks arranged to form a ring-shaped structure about a central axis, each of the fuel cell stacks having a stacking direction extending parallel to the central axis. The fuel cell unit also includes an annular cathode feed manifold surrounding the fuel cell stacks to deliver a cathode feed flow thereto, a plurality of baffles extending parallel to the central axis, each of the baffles located between an adjacent pair of the fuel cell stacks to direct a cathode feed flow from the annular cathode feed manifold and radially inwardly through the adjacent pair, and an annular cathode exhaust manifold surrounded by the fuel cell stacks to receive a cathode exhaust flow therefrom.

Abstract: A heat exchanger, such as a cathode recuperator for a high temperature fuel cell system, has a corrugated separator, a barrier and a plurality of flow channels. The corrugated separator has a surface positioned along a heat exchange fluid flow path, opposite ends of the separator having flattened corrugations. The barrier is positioned adjacent the surface. The plurality of flow channels are in the heat exchange fluid flow path and are at least partially defined by the surface and the barrier. The flattened corrugations are positioned adjacent crests in the corrugated separator and secured to the barrier.

Abstract: Relates to a process and apparatus that improves the hydrogen production efficiency for small scale hydrogen production. According to one aspect, the process provides heat exchangers that are thermally integrated with the reaction steps such that heat generated by exothermic reactions, combustion and water gas shift, are arranged closely to the endothermic reaction, steam reformation, and heat sinks, cool natural gas, water and air, to minimize heat loss and maximize heat recovery. Effectively, this thermally integrated process eliminates excess piping throughout, reducing initial capital cost.

Abstract: A fuel cell system (1) is provided and includes a fuel cell stack (3) and a heat transfer device (5) adapted to transfer heat from a cathode exhaust stream of the fuel cell stack (3) to water to be provided to a fuel inlet stream.

Abstract: A fuel cell unit includes a plurality of angularly spaced fuel cell stacks arranged to form a ring-shaped structure about a central axis, each of the fuel cell stacks having a stacking direction extending parallel to the central axis.

Abstract: An integrated fuel cell unit (10) includes an annular array (12) of fuel cell stacks (14), an annular cathode recuperator (20), an annular anode recuperator (22), a reformer (24), and an anode exhaust cooler (26), all integrated within a common housing structure (28).

Abstract: A catalytic reactor including a heat exchanger and a method are provided for transferring heat to a coolant and a reaction fluid. The catalytic reactor includes a reaction fluid flow path, a reaction region, and a coolant flow path. A reaction fluid catalytically reacts at a surface area in the reaction region thereby generating heat. The heat is transferred to a coolant and the reaction fluid based on the coolant and reaction fluid convective heat transfer coefficients respectively. In one embodiment, the ratio of the coolant convective heat transfer coefficient to the reaction fluid heat transfer coefficient is at least 5:1.

Abstract: A catalytic reactor/heat exchange device (10) is provided for generating a catalytic reaction in a reaction fluid flow (12) and transferring heat to a cooling fluid flow (14). The device includes reaction flow channels (20) with turbulators (30) therein. The turbulators (30) include an initial portion (40) and a selected portion (34) that includes a catalytic layer or coating (36) to initiate the desired catalytic reaction at a location (38) located downstream from the initial portion (40). In some preferred forms, each of the selected portions (34) of the turbulators (30) include at least one downstream section (103, 120) wherein the heat transfer performance has been intentionally reduced to improve performance of the device (10) during start up conditions.