Fusion engine

Abstract

A low enthalpy heat engine that uses two different ambient fluids (air and water) as the heat source 6 and sink or 16. Wax or a metal may be used as the heat sink in a piston and there may be four pistons 14 in the engine.

Description

This invention relates to a heat engine which produces continuous rotary mechanical motion in order to do useful work. The use of heat engines to produce continuous rotary mechanical motion is widespread, the application of these engines include the driving of other machines such as electrical generators, pumps, winches, or used for the propulsion of vehicles such as cars, trains or vessels etc. This Planet has two fluids in abundance, namely Air and Water. These two fluids often exist locally at differing temperatures due to the cyclic heating and cooling effect of the sun. Currently there is concern due to the overall mean temperature of these two predominant ambient fluids rising. The cause of this wanning effect is partly attributed to the current and past use of machines such as conventional turbines and engines which bum fossil fuels to raise the temperature of a working fluid up to its phase change temperature at its vaporisation stage, this is sometimes called the enthalpy or heat of vaporisation, in order to do useful work from the fluids volumetric expansion or contraction. The cold sink of most heat engines is usually the ambient air temperature; while the hot source side is usually increased in temperature by other means. Typically in a steam engine, water is used as the working fluid which undergoes a phase change at its vaporisation stage to steam after heating. Heat engines which require heating of the hot source, give easily detectable heat and noise emissions, which is not desirable in many applications. Other engines do exist which utilise working fluids with low vaporisation or condensation temperatures such as the Wally Minto wheel. Heat engines using refrigerants such as ammonia are used for ocean thermal energy conversion which exploits the temperature difference within an ocean, however most refrigerants have environmental or flammability risks associated with using them. Linear actuators are used for the opening and closing of greenhouse windows, these use a substance (usually paraffin wax) at or around its melting and solidification / freezing temperatures, this is sometimes called the heat of fusion or enthalpy of fusion stage when undergoing an endothermic reaction during melting, and called the heat of solidification or enthalpy of solidification stage when undergoing a exothermic reaction during freezing. However these cylinders are not used to produce a continuous rotary motion and the operation is caused by using a temperature variation in a single ambient fluid. A low enthalpy heat engine which could use the thermal energy contained within, or operate at temperatures close the predominant ambient fluid temperatures, would not contribute significantly to any environmental warming cycle. However most substances have a vaporisation and condensation temperatures above the ambient fluid temperatures and require heating or combustion to raise the working fluids temperature in order for them to undergo rapid expansion or contraction m order do useful work. If the heat contained within two different ambient fluids could be used as the heat source and sink for a heat engine, it could provide wide spread access to an energy source not restricted by the availability of fossil fuels or the dangers of nuclear energy, In order to achieve this, a heat engine whose working substance has a phase change temperature between or close to the two ambient fluid temperatures would be desirable as this would require little or no secondary heating or cooling of the working substance. In most substances the melting temperature or the temperature at which the heat or enthalpy of fusion occurs, and the freezing / solidification temperature or the temperature at which the heat or enthalpy of solidification occurs is usually at a lower temperature (enthalpy) than the vaporisation temperature often called the heat or enthalpy of vaporisation and the condensation temperature often called the heat or enthalpy of condensation. The term Latent heat which is the amount of heat supplied or emitted at these phase changes is often used in conjunction with these terms. Substances do exist which have phase change temperature at the melting and freezing / solidification stage between the two ambient fluid temperatures. There are metals which exist which have a high rate of thermal transfer, whose melting and freezing / solidification temperature is between the minimum and maximum ambient fluid temperatures of Air and Water, and which expand and contract significantly during the melting and freezing / solidification phase changes. This invention is a heat engine which transfers thermal energy to a working substance from a hot source in what is often referred to as an endothermic reaction at or near to the working substances melting temperature between solid and liquid often called the enthalpy or latent heat of fusion stage. The transfer of heat to the working substance causes it to undergo the phase change of melting resulting in a volumetric change in the working substance, the change in volume displaces the working substance or creates a pressure or vacuum if the working substance is constrained, this exerts a force on a connecting element to a rotating component, to a mass or buoyancy connected to a rotating component, or the rotating component itself. Hie working substance also transfers thermal energy often referred to as an exothermic reaction to a second cold sink fluid, at or near the working substances freezing / solidification temperature often called the latent heat or enthalpy of solidification phase change, this causes a reversal in the volumetric change of the working substance, this change in volume displaces the working substance or creates a pressure or vacuum if the working substance is constrained, which produces a corresponding force on the connecting element to the rotating component, to a mass or buoyancy connected to the rotating component or the rotating component itself. The arrangement of the forces produces continuous rotary' mechanical motion in order to do useful work. Hie mechanical construction of heat engines is application dependent, and the construction of a fusion engine may take many forms including, inline cylinder, horizontally apposed cylinder, rotary or radial etc Most engines which use combustion or vaporisation to exert a force on a piston or turbine blade have a degree of compressibility in the working fluid, this limits the peak forces exerted in the engine. The use of the fusion solid to liquid phase change has little or no compressibility in the working substance and as a consequence very' high internal pressures are apparent, This has benefits in terms of high torques, however to avoid damage to the engine it may be useful to use a pressure limiting device, or indirectly connect to the rotating component so that temperature variations in the hot source or cold sink fluid can be accommodated. There are many established ways in which this can be achieved in particular, Shear pm, spring, pneumatic or hydraulic cushioning or accumulator, buoyancy or weights connected to the rotating component which move in relation to gravity. The direction of motion in a fusion engine is dependent upon the substance, some substances will expand on freezing and some will contract. The direction of motion is dependent upon the working fluid chosen. A heat engine having a working substance which undergoes the phase changes of melting and freezing / solidification may have lower enthalpy than a vaporisation or combustion machine, and may utilise an ambient fluid as its hot source, and another ambient fluid as its cold sink or may utilise ground source water, river or lakes as either its hot source, or cold sink A heat engine having a working substance which undergoes the phase changes of melting and freezing may utilise a metal as its working substance to achieve fast thermal transfer rate or a Wax as its working substance to limit the peak internal pressures. The required energy use of the application, will determine the size of fusion engine required, established camot’s theorem and other thermodynamic principles exist which enable determination of the engine size. This invention will now be described by way of example and with reference to the accompany drawings in which: Figure 1 shows a plan view of a 4 cylinder in-line fusion engine Figure 2 shows an isometric view of the same 4 cylinder in-line fusion engine In figure 2, A Fusion engine includes cylinders 1,2,3,4, which house the working fluid 16.A cold sink fluid 5 which has a temperature below the working substances 16 Freezing temperature, A hot Source fluid 6 which has a temperature above the working substances 16 melting temperature. Each cylinder 1,2,3,4 has a piston 14, Seal 15 and a connecting rod 13 to transmit a force to the rod end bearing 11 via the shear pin 12.Each cylinder 1,2,3,4 is mounted on a pivot 7 which allows the cylinders to move in the vertical direction between the hot source fluid 6 and the cold source fluid 5 dependent upon the position of the crank 9.The working substance 16 is contained in the cylinders 1,2,3,4 by means of a seal 15. The cylinder piston 14 transmits a force through the cylinder rod 13 (shown in scrap view) to the rod end bearing 11, The transmitting of forces from the cylinder rod 13 to the rod end bearing 11 is by means of shear pin 12. In this example the shear pin 12 is utilised to prevent undue pressure on the crank 9 due to temperature variations. The cylinders 1,2,3,4 are mounted on a pivot 7, as the crank 9 rotates, the cylinders move vertically about the pivot 7. The cylinders 1,2,3,4 are immersed in either the hot source fluid 6 or the cold sink fluid 5 or partial immersion in both fluids. The vertical movement of the cylinders 1,2,3,4 causes cyclic immersion m either the hot source fluid 6 or cold sink fluid 5 dependent upon the cranks 9 orientation. The crank 9 turns in a rotary motion enabling usefill work output from the shaft of the crank 9 This fusion engine is located in Hope bay in Jamaica which at the time of writing has a sea temperature of 26 degrees Celsius, and an air temperature of 32 degrees Celsius. In this example Gallium is used as the working substance 16 which has a melting temperature of 29.76 degrees Celsius and expands 3.1% on solidification / freezing. Ambient air is used as the hot source fluid 6, sea water is used as the cold sink Fluid 5. If the fusion engine needs to operate in a different climate then the working substance 16 could be substituted for another substance, or alloy of Gallium such as Galinstan, with a different melting point. The hot source fluid 6 (Air) transfers some of its contained heat energy by way of thermal transfer to the cylinder 4 which is exposed to the hot source fluid 6, the cylinder 4 transfers heat into the working Substance 16 contained within it. The working Substance 16 when reaching its melting temperature undergoes a volumetric change. In this case with the working substance 16 being Gallium the volume reduces as it melts. As a result of the reduction in volume the piston 14 which contains seal 15 moves away from the crank 9 centreline, The crank 9 is supported by bearing 10 and the cylinder 4 is supported by its pivot 7, the distance between the pivot 7 and bearing 10 is constrained by their mounting, As a result of the movement of the connection rod 13 which is connected to the moving piston 14 the crank 9 is pulled towards the pivot 7, causing rotation of the crank 9 Cylinder 2 is immersed in the cold sink fluid 5 (Water) and heat is dissipated into the fluid from the working substance 16 through the cylinder 2 and into the cold sink fluid 5 this causes the working substance 16 to freeze due to its lowering temperature, and a change in volume occurs in the working substance 16. Galium on freezing will expand which exerts a pressure on its piston 15 this opposite to cylinder 4.The movement of the piston 14 of cylinder 2 is towards the crank 9 centreline. As a result of the movement of the connection rod 13 which is connected to the moving piston 14 the crank 9 is pushed away from the pivot 7, causing rotation of the crank 9 about its centreline. Cylinders 1, 3 are shown at their neutral positions (extended and retracted), at the neutral position, the cylinders 1,3 are partially immersed in both fluids undergoing an endothermic and exothermic reaction on the different sides of the cylinder . In these positions the working substance 16 has already gone through phase change temperature and little volumetric expansion or contraction takes place, Tire rotary motion of the shaft of the crank 9 shaft can be coupled to other machines, propellers fans wheels etc by means of suitable gearing in order to obtain a useful work output.

Claims

1) A heat engine which transfers thermal energy to a working substance from a hot source in what is often referred to as an endothermic reaction at or near to the working substances melting temperature between solid and liquid, sometimes called the enthalpy or latent heat of fusion stage. The transfer of heat to the working substance causes the working substance to undergo the phase change of melting resulting in a volumetric change in the working substance. This change in volume displaces the working substance or produces a pressure or vacuum if constrained, this exerts a force on a connecting element to a rotating component, to a mass or buoyancy connected to a rotating component, or the rotating component itself. The working substance also transfers thermal energy in what is often referred to as an exothermic reaction to a second cold sink fluid at or near the working substances solidification temperature often called freezing, this causes the working substance to solidify or freeze causing a reversal of the volumetric change, this change in volume displaces the working substance, or produces a pressure or vacuum if constrained, this exerts a force on a connecting element to a rotating component, to a mass or buoyancy connected to a rotating component, or the rotating component itself. The arrangement of the forces produces continuous rotary mechanical motion in order to do useful work.2) A heat engine as claimed in claim 1 wherein two different ambient fluids are used as the hot source and cold sink.3) A heat engine as claimed in claim 1 wherein an ambient fluid is used as its hot source or cold sink and ground source water, river or lakes are used as a hot source or cold sink.4) A heat engine according to any of the preceding claim wherein the force is applied indirectly through movement of a weight, buoyant part or the working substance itself, when connected to the rotating component.5) A heat engine according to any of the preceding claims wherein a metal is used as the working substance.6) A heat engine according to any of the preceding claims 1 to 4 wherein a wax is used as the working substance.7) A heat engine according to any of the preceding claim wherein a pressure limiting device is used to limit internal forces

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