A constant density heat exchanger and system for energy conversion 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 as the first flow control device and the second flow control device hold the volume of working fluid at constant density within the chamber.

A control system algorithm is provided for the computer control of a solid-state switching device in a Stirling-electric hybrid vehicle. The algorithm satisfies the demands for electrical energy management, regulation, allocation and distribution to the electrical system of the vehicle during the operation thereof. The control system controls the management, regulation, allocation and distribution of electrical current throughout the vehicle's electrical system in response to the commands of the vehicle operator. This includes the operation of wheel motors, electrical storage systems, the drivetrain and a plurality of other components, accessories and subsystems.

A control system algorithm is provided for the computer control of a solid-state switching device in a Stirling-electric hybrid vehicle. The algorithm satisfies the demands for electrical energy management, regulation, allocation and distribution to the electrical system of the vehicle during the operation thereof. The control system controls the management, regulation, allocation and distribution of electrical current throughout the vehicle's electrical system in response to the commands of the vehicle operator. This includes the operation of wheel motors, electrical storage systems, the drivetrain and a plurality of other components, accessories and subsystems.

In a gamma free-piston Stirling cooler driven by linear electric motors, a motor operating frequency for consuming minimum electric power is detected and a different motor operating frequency that delivers maximum thermal cooling power is detected. The frequencies are detected by varying the operating frequency in small steps while sensing (1) the motor power input to maintain a steady temperature or (2) the thermal cooling power of the Stirling cooler. A mode detection routine detects whether the appropriate freezer operation is the electric power minimization mode or the thermal cooling power maximization mode based upon the current thermal conditions in the freezer. When the freezer is sufficiently cold, the pistons of the Stirling cooler are driven at the minimum electric power consumption frequency. When the temperature is, or is likely to become, too warm, the pistons of the Stirling cooler are driven at the maximum thermal cooling power frequency.

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.

A system for recovery of energy in residue gases, comprising at least two energy conversion units (1), including a combustion chamber (2) having a fuel inlet (9), and a Sterling engine (4) having a heat exchanger (3) with a set of tubes containing working fluid, a portion of the heat exchanger extending into the combustion chamber (2). The system further comprises a pressure control system including a high-pressure reservoir (21) of working fluid, a low-pressure reservoir (22) of working fluid, a pressure pump (23) configured to maintain a pressure difference between the reservoirs, and a control arrangement (31, 32, 33) to regulate a pressure in the fluid circuit.

An energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly. The engine assembly may include a first monolithic body segment and a plurality of second monolithic body segments directly coupled or directly couplable to the first monolithic body segment. The first monolithic body segment may define a combustion chamber and a recirculation pathway in fluid communication with the combustion chamber. The recirculation pathway may be configured to recirculate combustion gas through the combustion chamber. The plurality of second monolithic body segments may respectively define at least a portion of a piston chamber and a plurality of working-fluid pathways fluidly communicating with the piston chamber.

The present invention relates to a multi-stage Stirling cycle machine and a steady-state operating parameter control method therefor. In the Stirling cycle machine, a mechanical energy input piston, a mechanical energy transfer double-acting free piston and a mechanical energy output piston constitute a plurality of Stirling working units which are arranged in stages. The mechanical energy input piston is connected to a mechanical energy input apparatus, and the mechanical energy output piston is connected to a mechanical energy output apparatus. When the Stirling cycle machine in the present invention is used as an engine, a relatively small amount of mechanical energy is input into a mechanical energy input piston in a set of pistons, the mechanical energy is amplified by a multi-stage Stirling unit, and a relatively large amount of mechanical energy is then output by a mechanical energy output piston. In the present invention, the required piston motion mode is realized by means of parameter calculation, selection and design, such that the multi-stage Stirling cycle machine can adapt to changes in an input condition and adjust an output power as required. The device in the present invention has a simple structure, a good adjustment performance, a small mechanical loss and a small deadvolume, is suitable for use with a large-diameter piston, and can be widely applied to waste heat power generation and distributed energy and renewable energy power generation.

The present invention relates to a multi-stage Stirling cycle machine and a steady-state operating parameter control method therefor. In the Stirling cycle machine, a mechanical energy input piston, a mechanical energy transfer double-acting free piston and a mechanical energy output piston constitute a plurality of Stirling working units which are arranged in stages. The mechanical energy input piston is connected to a mechanical energy input apparatus, and the mechanical energy output piston is connected to a mechanical energy output apparatus. When the Stirling cycle machine in the present invention is used as an engine, a relatively small amount of mechanical energy is input into a mechanical energy input piston in a set of pistons, the mechanical energy is amplified by a multi-stage Stirling unit, and a relatively large amount of mechanical energy is then output by a mechanical energy output piston. In the present invention, the required piston motion mode is realized by means of parameter calculation, selection and design, such that the multi-stage Stirling cycle machine can adapt to changes in an input condition and adjust an output power as required. The device in the present invention has a simple structure, a good adjustment performance, a small mechanical loss and a small deadvolume, is suitable for use with a large-diameter piston, and can be widely applied to waste heat power generation and distributed energy and renewable energy power generation.

A Stirling engine can take advantage of adiabatic compression (which heats working gas leaving the cold cylinder) and adiabatic expansion (which cools working gas leaving the hot cylinder) to increase efficiency. In some implementations, partially-heated gas leaving the cold cylinder and partially-cooled gas leaving the hot cylinder can be routed directly to a regenerator using bypass paths that are opened using one-way valves. The resultant relatively reduced temperature difference across the regenerator, e.g., as compared to a typical Stirling engine, can reduce thermal loss and improve efficiency. In some implementations, the compression ratios of the Stirling engine can be adjusted such that the temperature of the adiabatic heated gas is the same or higher than the temperature of the adiabatic cooled temperatures, thus eliminating the need for a regenerator.