In some embodiments the disclosure is directed to a closed-loop piston engine system using a recirculating carbon dioxide (CO.sub.2) system with supercritical carbon dioxide (scCO.sub.2) as a working fluid. The closed-loop piston engine system may include a scCO.sub.2 injector; a superheating nozzle region; a first valve; a second valve; a piston moving in the cylinder and coupled with a crankshaft, the piston being driven toward a centerline of the crankshaft during a power stroke using a connecting rod and causing the crankshaft to rotate thereby causing one power stroke per piston per crankshaft rotation and thereby producing two power strokes for every single power stroke that a similar engine would produce if run as a hydrocarbon fuel powered internal combustion engine. The recirculating CO.sub.2 system recirculates the used carbon dioxide and there are no carbon dioxide emissions from the system.

In some embodiments the disclosure is directed to a closed-loop piston engine system using a recirculating carbon dioxide (CO.sub.2) system with supercritical carbon dioxide (scCO.sub.2) as a working fluid. The closed-loop piston engine system may include a scCO.sub.2 injector; a superheating nozzle region; a first valve; a second valve; a piston moving in the cylinder and coupled with a crankshaft, the piston being driven toward a centerline of the crankshaft during a power stroke using a connecting rod and causing the crankshaft to rotate thereby causing one power stroke per piston per crankshaft rotation and thereby producing two power strokes for every single power stroke that a similar engine would produce if run as a hydrocarbon fuel powered internal combustion engine. The recirculating CO.sub.2 system recirculates the used carbon dioxide and there are no carbon dioxide emissions from the system.

A high efficiency steam engine or steam expander includes a cylinder, cylinder head and piston in which cylinder clearance volume is zero or nearly zero together with a negligible amount of compression such that any pressure in the cylinder clearance volume just before the power stroke is as low as ambient pressure or condenser pressure to provide superior thermal efficiency in a compact compound engine having a high pressure expansion chamber within the piston and low pressure chamber in the cylinder. The inlet valve is opened slightly by piston movement and a steam assist force then drives it to its fully open position. Steam passes from the high pressure chamber to the low pressure chamber through a transfer valve located in the head of the piston and steam is released through an automatic exhaust valve in the cylinder head.

A high efficiency steam engine or steam expander includes a cylinder, cylinder head and piston in which cylinder clearance volume is zero or nearly zero together with a negligible amount of compression such that any pressure in the cylinder clearance volume just before the power stroke is as low as ambient pressure or condenser pressure to provide superior thermal efficiency in a compact compound engine having a high pressure expansion chamber within the piston and low pressure chamber in the cylinder. The inlet valve is opened slightly by piston movement and a steam assist force then drives it to its fully open position. Steam passes from the high pressure chamber to the low pressure chamber through a transfer valve located in the head of the piston and steam is released through an automatic exhaust valve in the cylinder head.

A fluid energy harvester, including a housing having at least one port and an outlet, and the housing defining at least one fluid passageway therein. The fluid energy harvester also includes a converter disposed within the housing and configured to convert at least a portion of potential energy in an exhaust fluid, a generator operably coupled to the converter and configured to generate an electrical current from the converter, a charging controller electrically coupled to the generator, and a storage medium electrically coupled to the generator and configured to store the electrical current generated by the generator. The fluid energy harvester further includes a nozzle configured to control a flow of the exhaust fluid.

A fluid energy harvester, including a housing having at least one port and an outlet, and the housing defining at least one fluid passageway therein. The fluid energy harvester also includes a converter disposed within the housing and configured to convert at least a portion of potential energy in an exhaust fluid, a generator operably coupled to the converter and configured to generate an electrical current from the converter, a charging controller electrically coupled to the generator, and a storage medium electrically coupled to the generator and configured to store the electrical current generated by the generator. The fluid energy harvester further includes a nozzle configured to control a flow of the exhaust fluid.

A closed cycle engine power structure and a power generation method, includes a cylinder block and an inner shell. The inner shell is located at the cylinder block, and the inner enclosed cavity of the cylinder block is divided into an outer duct and an inner duct, and an electric coil is arranged in the inner shell. An Archimedes pump is arranged in the inner duct, the electric coil is in drive connection with the Archimedes pump to form a motor structure. Tension structures are arranged in the outer duct. The Archimedes pump is driven to rotate to form a pressure difference between the top and bottom of the cylinder block, generating airflow around the tension structures. According to Bernoulli principle, the pulling force is generated by tension structures. The tension structures concentrate on the cylinder block to form the power of the engine power structure.

A closed cycle engine power structure and a power generation method, includes a cylinder block and an inner shell. The inner shell is located at the cylinder block, and the inner enclosed cavity of the cylinder block is divided into an outer duct and an inner duct, and an electric coil is arranged in the inner shell. An Archimedes pump is arranged in the inner duct, the electric coil is in drive connection with the Archimedes pump to form a motor structure. Tension structures are arranged in the outer duct. The Archimedes pump is driven to rotate to form a pressure difference between the top and bottom of the cylinder block, generating airflow around the tension structures. According to Bernoulli principle, the pulling force is generated by tension structures. The tension structures concentrate on the cylinder block to form the power of the engine power structure.

In some embodiments the disclosure is directed to a closed-loop piston engine system using a recirculating carbon dioxide (CO.sub.2) system with supercritical carbon dioxide (scCO.sub.2) as a working fluid. The closed-loop piston engine system may include a scCO.sub.2 injector; a superheating nozzle region; a first valve; a second valve; a piston moving in the cylinder and coupled with a crankshaft, the piston being driven toward a centerline of the crankshaft during a power stroke using a connecting rod and causing the crankshaft to rotate thereby causing one power stroke per crankshaft rotation and thereby producing two power strokes for every single power stroke that a similar engine would produce if run as a hydrocarbon fuel powered internal combustion engine. The recirculating CO.sub.2 system recirculates the used carbon dioxide and there are no carbon dioxide emissions from the system.

In some embodiments the disclosure is directed to a closed-loop piston engine system using a recirculating carbon dioxide (CO.sub.2) system with supercritical carbon dioxide (scCO.sub.2) as a working fluid. The closed-loop piston engine system may include a scCO.sub.2 injector; a superheating nozzle region; a first valve; a second valve; a piston moving in the cylinder and coupled with a crankshaft, the piston being driven toward a centerline of the crankshaft during a power stroke using a connecting rod and causing the crankshaft to rotate thereby causing one power stroke per crankshaft rotation and thereby producing two power strokes for every single power stroke that a similar engine would produce if run as a hydrocarbon fuel powered internal combustion engine. The recirculating CO.sub.2 system recirculates the used carbon dioxide and there are no carbon dioxide emissions from the system.