NOVELTY - An energy recovery system (100) comprises: a base energy conversion system (110) to convert energy into high- and low-grade waste heat components, where high-grade component is at a higher temperature than the low-grade component; hydrogen processor to utilize heated water vapor to generate hydrogen gas; and low-grade heat recovery and conveyance system that is coupled with the base energy conversion system to transport the low-grade component to the processor, and is configured to vaporize water for transporting a portion of the low-grade component in the form of latent heat.    USE - As energy recovery system which is useful for recovering waste heat (claimed) that is generated by a base energy conversion system and utilize the waste heat in the production of hydrogen fuel (e.g. hydrogen gas).    ADVANTAGE - The energy recovery systems increase the overall efficiency of the base energy conversion systems, while producing hydrogen fuel in an economical and an environmentally beneficial manner. Certain of such systems are operated on a relatively small scale, such as at a residential building or onboard an automotive vehicle. The systems thus provide hydrogen fuel locally, which reduces or eliminates challenges that are associated with the distribution of hydrogen fuel.    DETAILED DESCRIPTION - An energy recovery system (100) comprises: a base energy conversion system (110) that is configured to convert energy into a high-grade waste heat component and a low-grade waste heat component, where the high-grade waste heat component is at a higher temperature than is the low-grade waste heat component; a hydrogen processor that is configured to utilize heated water vapor to generate hydrogen gas; and a low-grade heat recovery and conveyance system that is coupled with the base energy conversion system so as to transport the low-grade waste heat component to the hydrogen processor. The low-grade heat recovery and conveyance system is configured to vaporize water so as to transport at least a portion of the low-grade waste heat component in the form of latent heat. The vaporized water is heated by at least a portion of the high-grade waste heat component within the low-grade heat recovery and conveyance system as the vaporized water is transported to the hydrogen processor. The energy recovery system further comprises: a heat recovery module that comprises a first and second environment that are physically separated from each other and that are configured to interact with each other via a thermal interface; a high-grade heat recovery and conveyance system that is coupled with the base energy conversion system so as to transport the high-grade heat component to the first environment of the heat recovery module, where the low-grade heat recovery and conveyance system is configured to provide the vaporized water to the second environment so that the vaporized water can be heated by at least a portion of the high-grade waste heat component; and a superheater that is configured to receive waste heat energy from the hydrogen processor. The base energy conversion system comprises an internal combustion engine (112), where exhaust from internal combustion engine comprises the high-grade waste heat component, and engine coolant that cycles from the internal combustion engine comprises the low-grade waste heat component. The low-grade heat recovery and conveyance system comprises a vaporizer having a chamber and a heat exchanging pathway through which the engine coolant flows, where liquid water that is introduced into the chamber draws sensible heat from the engine coolant so as to undergo a change of state; a mechanical vapor recompressor, where vaporized water from the vaporizer is introduced into the mechanical vapor recompressor via one-way valves. The low-grade heat recovery and conveyance system is configured to draw more sensible heat from the engine coolant for a given mass of liquid water that is introduced into the chamber than if the water were introduced into the chamber having already been vaporized due to the latent heat of vaporization of the water, such that the liquid water can serve as a low mass energy carrier. The base energy conversion system, hydrogen processor, and low-grade heat recovery and conveyance system are positioned onboard an automotive vehicle. The base energy conversion system comprises a cooling system (118) that is configured to remove the low-grade waste heat component from the base energy conversion system. INDEPENDENT CLAIMS are included for the following:    (1) recovering waste heat involving removing a first variety of waste heat from a base energy conversion system; delivering the waste heat to a vaporizer; introducing liquid water into the vaporizer; heating the liquid water with at least a portion of the waste heat so as to transition the liquid water to a vapor; and transporting the water vapor to a hydrogen processor; and    (2) a vapor transport device comprising: a tube; a first cap positioned at a first region of the tube, a second cap positioned at a second region of the tube, and a piston positioned between the first cap and the second cap so as to divide the tube into a first chamber of variable size that extends between the first cap and the piston and a second chamber of variable size that extends between the piston and the second cap; a drive shaft connected to the piston and extending through the second cap, where the drive shaft is configured to translate the piston between the first and second caps; and one-way valves, where each of the first and second cap, and the piston comprises one-way valves that are oriented so as to permit vapor to flow from a position outside of the tube into the first chamber, from the first chamber to the second chamber, and from the second chamber to a position outside of the tube, but to prevent vapor flow from the first chamber to a position outside of the tube and from the second chamber to the first chamber.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an energy recovery system that is configured to utilize waste heat from a base energy conversion system in the generation of hydrogen fuel.    Energy recovery system (100)    Base energy conversion system (110)    Base fuel (111)    Internal combustion engine (112)    Electrical generator (114)    Exhaust system (116)    Engine cooling system (118)