This application relates to a heat transfer apparatus and method employing an active regenerative cycle. The invention employs a working or “active” fluid and a heat transfer fluid which are physically separated. The working fluid is contained in an array of refrigeration elements that are distributed over the temperature gradient of a regenerative bed. The work for the refrigeration cycle is provided by alternative compression and expansion of the working fluid in each of the refrigeration elements at a temperature corresponding to the element's location in the temperature gradient. The compression and expansion strokes may be coupled together for optimum work recovery. The heat transfer fluid is circulated relative to the working fluid between a thermal load and a heat sink to enact a refrigeration cycle having improved energy efficiency.

Heat transfer apparatus and method employing active regenerative cycle

Systeme d'echangeur de chaleur pour un moteur Stirling comprenant un radiateur (30) relie a l'espace d'expansion (32) par une paire de conduites d'ecoulement paralleles (34, 36), et un refroidisseur (40) relie a l'espace de compression (42) par une paire de conduites d'ecoulement paralleles (44, 46). heat exchanger system for a Stirling engine comprising a radiator (30) connected to the expansion space (32) by a pair of parallel flow conduits (34, 36) and a cooler (40) connected to the compression space (42) by a pair of parallel flow conduits (44, 46). Un circulateur (38, 48) est dispose entre une des conduites du radiateur et une des conduites du refroidisseur pour faire circuler en continu le fluide de travail depuis l'espace de travail, au travers de l'echangeur de chaleur, et de nouveau dans le meme espace de travail. A circulator (38, 48) is arranged between one of the pipes of the radiator and a pipe cooler for continuously circulating the working fluid from the workspace, through the heat exchanger, and again in the same workspace. Des etapes d'expansion et de compression sont ainsi rendues plus isothermiques et les echangeurs de chaleur peuvent avoir des dimensions plus reduites, tout en etant plus efficaces et presentant une chute de pression plus faible. expansion and compression steps are thus made more isothermal and heat exchangers may have more reduced dimensions, while being more efficient and presenting a lower pressure drop.

Stirling engine with parallel flow heat exchangers

An apparatus is provided for compressing/expanding a refrigerant gas. The pistons 13 and 16 for use in the apparatus each have cavities formed in the pistons 13 and 16, and check valves 40 and 41 mounted on one end of the respective pistons for closing/opening the cavities so that the cavities are filled with the pressurized gas. The pistons also have a multiplicity of bores 42 and 43 communicating with the respective cavities for ejecting the high pressure gas into respective gaps between the pistons and cylinders accommodating the pistons. The ejected gas forms gas bearings for the pistons, keeping the pistons off the cylinders, thereby eliminating any mechanical friction between them and hence wear of the pistons and the cylinders. This helps significantly prolong life time of the apparatus.

Gas compression/expansion apparatus

A Stirling cycle engine includes: a housing having at least one cylinder; a motor element disposed in the housing; and a Stirling refrigerator portion driven by the motor element. The cylinder is made to be a cross guide for a piston or a displacer of the Stirling refrigerator portion. Thus, it is possible to provide a desired Stirling cycle engine, for example, a Stirling refrigerator, a Stirling engine generator, etc. with a single configuration.

Stirling cycle engine

PHN.10.716 23 ABSTRACT: A thermodynamic oscillator having a displacer (5) and a piston (3) (further displacer) movable due to pressure fluctuations at the resonance frequency of the oscillator. The displacer (5) and the piston (3) are located in a working space (11,15) which is filled with working medium and can be connected through a release valve (51,125,167) and a supply valve (53,129,169), res-pectively, to a single reservoir (55) filled with working medium with an increase and a decrease, respectively, of the ambient temperature with respect to a nominal temper-ature. The valves (51,53,125,129,167,169) have an open-ing pressure which is a function of the ambient temper-ature. The average pressure and the resonance frequency of the oscillator can thus be stabilized at a variable ambient temperature. The oscillator can be operated as a cold-gas engine, a hot-gas engine (motor), a heat pump or a current generator.

Thermodynamic oscillator with average pressure control

A Stirling cycle heat engine is disclosed in which displacer motion is controlled as a function of the working fluid pressure P 1 and a substantially constant pressure P 0 . The heat engine includes an auxiliary chamber at the constant pressure P 0 . An end surface of a displacer piston is disposed in the auxiliary chamber. During the compression portion of the engine cycle when P 1 rises above P 0 the displacer forces the working fluid to pass from the cold chamber to the hot chamber of the engine. During the expansion portion of the engine cycle the heated working fluid in the hot chamber does work by pushing down on the engine's drive piston. As the working fluid pressure P 1 drops below P 0 the displacer forces most of the working fluid in the hot chamber to pass through the regenerator to the cold chamber. The engine is easily combinable with a refrigeration section to provide a refrigeration system in which the engine's single drive piston serves both the engine and the refrigeration section.

Walter H. Higa

Papers

Stirling cycle engine and refrigeration systems