A Stirling engine comprising: a crank case (1) with a crank shaft (2) arranged therein, a displacer cylinder (3) with a reciprocatingly arranged displacer piston (4) therein, said displacer piston (4) being connected to said crank shaft (2) via a connecting rod (5) extending through a first end of said displacer cylinder (3), and wherein the displacer cylinder (3) defines a hot chamber (6) and a cool chamber (7) separated by the displacer piston (4), a working cylinder (8) defining a working cylinder chamber (11) with a reciprocatingly arranged working piston (9) therein, said working piston (9) being connected to said crank shaft (2) via a connecting rod (10) extending through a first end of the working cylinder (8), a heater device (14), arranged at a second end of said displacer cylinder (3) opposite to said first end and configured to heat a working gas which is present in the hot chamber (6) of the displacer cylinder (3) and in fluid communication with the working cylinder chamber (11) through a working gas channel which comprises a first heat exchanger (16) extending from a head (19) of the displacer cylinder (3) into the heater device (14), and a second heat exchanger (17) formed by a regenerator arranged outside the heater device (14). The regenerator (17) comprises a regenerator element (17) formed by metal foam that has an open porosity.

A Stirling engine includes a working cylinder defining a working cylinder chamber with a reciprocatingly-arranged working piston and a heater fluidly communicating with the working cylinder chamber through a working gas channel. The engine includes a first heat exchanger extending from a head of a displacer cylinder into the heater, a second heat exchanger formed by a regenerator arranged outside the heater, and a third heat exchanger formed by a cooler arranged between the regenerator and the working cylinder chamber. At any point along the working gas channel, as seen cross-wise to an assumed working gas flow direction through the working gas channel, the cross section area of the working gas channel defined by the first, second and third heat exchangers is within the range of the medium cross section area of the working gas channel +/−10%.

A Stirling engine includes a working cylinder defining a working cylinder chamber with a reciprocatingly-arranged working piston and a heater fluidly communicating with the working cylinder chamber through a working gas channel. The engine includes a first heat exchanger extending from a head of a displacer cylinder into the heater, a second heat exchanger formed by a regenerator arranged outside the heater, and a third heat exchanger formed by a cooler arranged between the regenerator and the working cylinder chamber. At any point along the working gas channel, as seen cross-wise to an assumed working gas flow direction through the working gas channel, the cross section area of the working gas channel defined by the first, second and third heat exchangers is within the range of the medium cross section area of the working gas channel +/−10%.

A single-piece regenerator having at least two portions, at least one of the portions having a porosity which differs from a porosity of an adjacent portion, and each of the portions of the regenerator being made of a porous rigid material with a given porosity.

A free piston Stirling engine with a heat exchanger that has an inner component part assembled within an outer component part. The outer component part has a tubular outer wall and circumferentially spaced ridges that extend radially inward from the tubular outer wall and are separated from each other by inward opening slots. The inner component part has a tubular inner wall and circumferentially spaced ridges that extend outward from the inner tubular wall and are separated from each other by outward opening slots. The ridge widths of the outer and inner component parts are less than the slot widths of the corresponding slots into which they fit. The two component parts are assembled with the ridges of each component part extending into the slots of the other component part to form gas passages between interfacing sidewall surfaces of the ridges.

A free piston Stirling engine with a heat exchanger that has an inner component part assembled within an outer component part. The outer component part has a tubular outer wall and circumferentially spaced ridges that extend radially inward from the tubular outer wall and are separated from each other by inward opening slots. The inner component part has a tubular inner wall and circumferentially spaced ridges that extend outward from the inner tubular wall and are separated from each other by outward opening slots. The ridge widths of the outer and inner component parts are less than the slot widths of the corresponding slots into which they fit. The two component parts are assembled with the ridges of each component part extending into the slots of the other component part to form gas passages between interfacing sidewall surfaces of the ridges.

A method for pressurisation of a working gas in a Stirling engine assembly for use in a thermal energy plant, the Stirling engine assembly including: a Stirling engine including an expansion cylinder and a compression cylinder, wherein the expansion and compression cylinders are configured in a V-arrangement; a regenerator; a cooler and a heater; an accumulator, the accumulator being in fluidic connection with the expansion and/or compression cylinders of the Stirling engine; and a low pressure receptacle including the working gas. The method includes: providing working gas to the accumulator from the low pressure receptacle; providing a pressurisation fluid to the accumulator to reduce the volume for the working gas in the accumulator, thereby increasing the pressure of the working gas in the accumulator; and displacing the pressurised working gas from the accumulator to the expansion and/or compression cylinder.

A method for pressurisation of a working gas in a Stirling engine assembly for use in a thermal energy plant, the Stirling engine assembly including: a Stirling engine including an expansion cylinder and a compression cylinder, wherein the expansion and compression cylinders are configured in a V-arrangement; a regenerator; a cooler and a heater; an accumulator, the accumulator being in fluidic connection with the expansion and/or compression cylinders of the Stirling engine; and a low pressure receptacle including the working gas. The method includes: providing working gas to the accumulator from the low pressure receptacle; providing a pressurisation fluid to the accumulator to reduce the volume for the working gas in the accumulator, thereby increasing the pressure of the working gas in the accumulator; and displacing the pressurised working gas from the accumulator to the expansion and/or compression cylinder.

The invention relates to a liquid air energy storage system. The storage system includes a cryocooler, a dewar, and a Sterling engine. The cryocooler cools a tip of a cold head to cryogenic temperatures, the cryocooler further includes a heat sink to reject heat from the cryocooler and a cold head that protrudes into a dewar through a cryocooler cavity, the cold head to condense ambient air to create liquified air in the dewar. The dewar holds the liquified air at low temperatures, the dewar having the cryocooler cavity and a Stirling cavity. The Stirling engine drives an electric generator, the Stirling engine further including a cold finger protruding into the dewar through the Stirling cavity, the cold finger to move the liquified air from the dewar to a Stirling heat sink; the Stirling heat sink to expand the liquified air; and the electric generator to generate output electricity.

The invention relates to a liquid air energy storage system. The storage system includes a cryocooler, a dewar, and a Sterling engine. The cryocooler cools a tip of a cold head to cryogenic temperatures, the cryocooler further includes a heat sink to reject heat from the cryocooler and a cold head that protrudes into a dewar through a cryocooler cavity, the cold head to condense ambient air to create liquified air in the dewar. The dewar holds the liquified air at low temperatures, the dewar having the cryocooler cavity and a Stirling cavity. The Stirling engine drives an electric generator, the Stirling engine further including a cold finger protruding into the dewar through the Stirling cavity, the cold finger to move the liquified air from the dewar to a Stirling heat sink; the Stirling heat sink to expand the liquified air; and the electric generator to generate output electricity.