AU775136B2 - Composite heat engine - Google Patents

Description

P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Actual Inventor Address for service is: STEPHEN LANYI STEPHEN LANYI WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 Attorney code: WR Invention Title: "Composite Heat Engine" n The following statement is a full description of this invention, including the best method of performing it known to me:- -2- Title Composite Heat Engine Field of the Invention This invention relates to a heat engine.

Background Art A heat engine is a system operating in a cycle and producing a net quantity of work from a supply of heat. An example of a heat engine is a steam engine.

In a steam engine, steam functioning as a working fluid leaves the heat chamber (boiler), taking with it all heat energy it absorbed during the heating process.

This introduces significant losses in the performance of the steam engine as much of the heat energy is wasted.

It would be advantageous to provide a heat engine in which a working fluid does not leave the heat chamber carrying to complete waste all the heat energy which was absorbed by the working fluid in the heat chamber.

S~ 15 Disclosure of the Invention Broadly, the present invention provides a heat engine comprising: means for establishing a temperature gradient between two spaced apart zones within a heat chamber; a first fluid circuit at least in part moveable between the two spaced apart zones and adapted to contain a working fluid which, when in part of the first fluid circuit, expands and contracts on movement of the first fluid ~circuit between the two zones so as to perform work; and displacement means for moving the first fluid circuit between the two spaced apart zones so as to provide for the reciprocal generation of work.

3/1 In preferred arrangement of the invention the heat engine further comprises a second fluid circuit also at least in part moveable between the two spaced apart zones and adapted to contain a working fluid which, when in part of the second fluid circuit, expands and contracts on movement of the second fluid circuit between the two zones so as to perform work, the displacement means for moving the first and second fluid circuits between the two spaced apart zones so as to provide for the reciprocal generation of work.

In this preferred arrangement the heat chamber is adapted to contain a heat fluid that provides the temperature gradient between the two spaced apart zones, and the parts of the first and second fluid circuits are respectively provided in first and second heat exchangers adapted for reciprocatory movement within the heat chamber in opposed relation between the two spaced apart zones whereby one heat exchanger moves towards one of said zones while the other heat exchanger moves towards the other of said zones.

The working fluid in each fluid circuit flowing out of, and returning to, the heat chamber during the expansion and contraction stages is in a liquid state.

Because the working fluid actually leaving the heat chamber is in a liquid state (as opposed to the gaseous state in which that portion of the working fluid accommodated in the respective heat exchanger exists when heated), any significant heat loss from the heat chamber is avoided. In other words, the working fluid leaving the heat chamber does not carry to waste heat energy which has been absorbed in the heat chamber. This avoids the massive heat losses which are associated with conventional heat engines.

Because there is no significant heat loss from the heat chamber, heat energy in 25 the heat chamber can be constantly and continuously re-used. This is particularly significant in terms of the efficiency of the heat engine according to the invention.

0 0 00 a 0 0 Each fluid circuit may include a high pressure reservoir and a low pressure reservoir, both of which are located outside of the heat chamber, the fluid circuit -3/2being arranged to deliver working fluid upon expansion thereof to the high pressure reservoir and to return working fluid upon contraction thereof from the low pressure reservoir, the pressure differential in the two reservoirs being utilised to generate the work.

-4- Each working fluid may perform work upon expansion thereof by acting on a hydraulic ram at said location outside of the heat chamber.

Preferably, each hydraulic ram is of the double-acting type having two operating chambers separated by a piston. Working fluid is delivered alternatively to the two operating chambers in timed sequence. Working fluid is delivered to each chamber at a relatively high pressure to cause operation of the hydraulic ram and is subsequently discharged at a relatively low pressure. With this arrangement, the high pressure reservoir and the low pressure reservoir each communicate with the operating chambers of the hydraulic ram in timed sequence whereby fluid from the high pressure reservoir can alternately enter each operating chamber of the hydraulic ram to cause the ram to undergo a stroke and whereby the spent working fluid in the other operating chamber discharges to the low pressure reservoir during that stroke.

Each fluid circuit may further include at least one internal reservoir which is located within the heat chamber and which receives the working fluid.

In a typical embodiment of the invention, the working fluid may be water. In such a case, the water in each fluid circuit would be in the form of steam within ~the upper level of the respective heat exchanger and in the form of water within the lower level of the respective heat exchanger and the remainder of the fluid circuit.

Preferably there are two of said internal reservoirs, one of which is located in close proximity to the respective heat exchanger and moves in unison therewith, and the other of which is located in a region of the heat chamber corresponding to the low temperature end of the temperature gradient.

25 The two internal reservoirs contain the working fluid in its liquid form.

The first and second heat exchangers may each comprise a plurality of pipes arranged in a cluster, one end of each pipe being closed and the other end of each pipe communicating with a manifold forming part of the respective fluid circuit.

Preferably, the pipes in each cluster are positioned in side-by-side relationship and the manifold is disposed in a generally horizontal plane.

Preferably, the pipes are so positioned that the closed end thereof is uppermost when the heat chamber is at the extent of its movement towards the zone of higher temperature within the heat chamber.

Each fluid circuit may include a flexible portion to accommodate the reciprocatory movement of the respective heat exchanger within the heat chamber.

The heat fluid contained within the heat chamber preferably comprises a high temperature resistant fluid such as air or nitrogen.

Each heat exchanger may be mounted on a rocker assembly adapted for limited pivotal movement about a horizontal pivot axis, each exchanger being disposed to one side of the pivot axis whereby one heat exchanger is caused to ascend within the heat chamber while the other heat exchanger descends, and vice versa.

Conveniently, the temperature gradient within the heat chamber is maintained between about 4000C and ambient temperature.

Brief Description of the Drawings The invention will be better understood by reference to the following description of one specific embodiment thereof as shown in the accompanying drawings in which: -6- Figure 1 is a schematic side view of a heat engine according to the embodiment; Figure 2 is a schematic plan view of the heat engine; Figure 3 is a schematic side view of a drive system used in the heat engine; Figure 4 is a schematic side view of apparatus used for establishing a temperature gradient within a heat chamber forming part of the heat engine; and Figure 5 is a schematic view of a hydraulic ram by means of which the heat engine delivers useful work.

Best Mode(s) For Carrying Out The Invention The embodiment shown in the drawings is directed to a heat engine 10 for producing work from expansion and contraction of a working fluid which in this embodiment is in the form of water operating both in its liquid and gaseous states.

The heat engine 10 includes a closed heat chamber 12 containing a high temperature-resistant heat fluid, which in this embodiment is air.

The heat chamber 12 accommodates one or more sets of heat exchangers there being three sets in this embodiment.

20 Each set of heat exchangers 20 comprises a first heat exchanger 21 and a second heat exchanger 22.

A rocker structure 13 is provided within the heat chamber 12. The rocker structure 13 comprises a rocker arm 15 associated with each set of heat -7exchangers 20, each rocker arm being mounted on a support 17 for pivotal movement about a horizontal pivot axis 19. On one end of each rocker arm there is supported the respective first heat exchanger 21 and on the other end of the rocker arm there is supported the respective second heat exchanger 22.

With this arrangement, the two heat exchangers 21, 22 in each set 20 can undergo reciprocatory motion within the heat chamber 12 in opposed relation to each other; that is, one heat exchanger ascends within the heat chamber 12 while the other descends, and vice versa. A drive system 26, which is best seen in Figure 3 and which will be described in detail later, is provided to swing the rocker arms 15 back and forth about pivot axis 19 to cause the heat exchangers 21, 22 to ascend and descend in opposed relation.

A heating means 27 is provided for establishing a temperature gradient in the heat chamber 12 between the uppermost and lowermost zones thereof, as shown in Figure 4. In this embodiment, a temperature of about 400 0 C is established at the uppermost zone of the heat chamber 12 and an ambient temperature is established at the lowermost region of the heat chamber. The ambient temperature is established by introduction of ambient air into the lowermost region of the heat chamber 12, as will be described later.

Each heat exchanger 21, 22 comprises a plurality of pipe clusters 30 positioned 20 in spaced apart relationship one above another. In this embodiment, there are forty pipe clusters in each heat exchanger but only the uppermost pipe cluster 30a and the lowermost pipe cluster 30b are depicted in the drawings for sake of clarity. Each pipe cluster 30 comprises a plurality of pipes 31 positioned in side-by-side relationship. One end 32 of each pipe 31 is closed and the other 25 end 33 is connected to a horizontally disposed manifold 34.

The pipes 31 in each pipe cluster 30 are positioned in side-by-side parallel relationship and occupy a common plane. The pipes 31 are so arranged that .the closed end 32 thereof are uppermost when the respective heat exchanger -8- 21, 22 has ascended to its uppermost position within the heat chamber 12 (as shown by heat exchanger 22 in Figure 1 of the drawings).

Each pipe cluster 30 in the first heat exchanger 21 is incorporated in a respective first fluid circuit 41 of which the respective pipes 31 and manifold 34 form part. Similarly, each pipe cluster 30 in the second heat exchanger 22 forms part of a respective second fluid circuit 42 of which the respective pipes 31 and manifold 34 form part.

It should be noted that a separate fluid circuit is associated with each pipe cluster 30. In other words, for the forty pipe clusters within each heat exchanger 21, 22, there are forty separate fluid circuits, although only fluid circuits 41a, 41b respective associated with the uppermost pipe cluster 30a and lowermost pipe cluster 30b are shown in the drawings for the sake of clarity.

The fluid circuit 41a associated with pipe cluster 30a includes a first (upper) internal reservoir 51 supported on the rocker arm 15 for movement in unison with the heat exchanger 21, 22, and a second (lower) internal reservoir 52 positioned on the bottom of the heat chamber 12. Each internal reservoir 51, 52 comprises a vertically positioned cylinder. The vertical orientation of each of the two internal reservoirs 51, 52 ensures that working fluid (water) contained .therein has a temperature gradient, with the warmest fluid being at the top of the 20 first (upper) reservoir 51 and the coolest fluid being at the bottom of the second (lower) reservoir 52. Fluid flow line 53 provides for fluid communication between manifold 34 and the upper end of the first (upper) internal reservoir 51. A flexible fluid flow line 54 provides for fluid communication between the lower end of the first (upper) internal reservoir 51 and the upper end of the second (lower) internal reservoir 52. The flexible nature of the fluid flow line 54 accommodates relative movement between the first and second internal reservoirs 51, 52 as the respective heat exchanger 21, 22 ascends and descends in the heat chamber 12 upon rocking movement of the rocker arm 15 about pivot 19.

oo se -9- The fluid circuit 41a further includes a high pressure reservoir defined by vessel and a low pressure reservoir defined by vessel 57, both located on the outside of the heat chamber 12. The high pressure vessel 55 is connected for fluid communication with the second internal reservoir 52 by way of fluid flow line 61, and the low pressure vessel 57 is connected for fluid communication with the lower end of the second internal reservoir 52 by way of fluid flow line 63. A one-way valve 64 is incorporated in fluid flow line 61 so that working fluid can only flow in the direction from the internal reservoir 52 to the high pressure vessel 55. Similarly, a one-way valve 66 is incorporated in the fluid flow line 63 so that working fluid can only flow in the direction from the low pressure vessel 57 to the second internal reservoir 52.

A hydraulic ram 71 (see Figure 5) is provided to utilise a pressure differential established between the high pressure vessel 55 and the lower pressure vessel 57 to perform useful work, as will be explained in more detail later.

The hydraulic ram 71 is of the double-acting type, having two operating chambers 72, 73 separated by a piston 74. Each chamber 72, 73 is connected to the high pressure vessel 55 by way of intake circuit 79 which includes respective intake control valves 75. Each chamber 72, 73 is also connected to the low pressure vessel 57 by way of discharge circuit 76 which includes o 20 respective discharge control valves 77. With this arrangement, water is 000delivered alternately to the two operating chambers 72, 73 from the high pressure vessel 55 in timed sequence under the control of the intake control valves 75. Water is delivered to each chamber 72, 73 at a relatively high pressure to cause operation of the hydraulic ram. The water is subsequently 25 discharged at a relatively low pressure through the discharge circuit 76 under the control of the discharge valves 77. In this way, the high pressure vessel and the low pressure vessel 57 each communicate with the operating chambers 72, 73 of the hydraulic ram in sequence whereby water from the high pressure vessel can alternately enter each operating chamber of the hydraulic ram to *o° cause the ram to undergo a stroke and whereby the spent water in the other operating chamber discharges to the low pressure vessel 57 during that stroke.

The high pressure vessel 55 is maintained at a generally constant pressure. In this embodiment, the constant pressure within vessel 55 is maintained by a source 68 of compressed air at constant pressure communicating with the upper end of vessel by way of air line As previously mentioned, there is a separate fluid circuit 41 associated with each pipe cluster 30. The actual pressure at which the high pressure vessel in each fluid circuit 41 is maintained varies according to the particular pipe cluster 30 with which the fluid circuit is associated. For instance, the high pressure vessel associated with the uppermost pipe cluster 30a in each heat exchanger is at a pressure of about 226 Atmospheres and the corresponding lower pressure vessel 57 is at a pressure of about 115 Atmospheres.

Accordingly, there is a pressure differential of about 110 Atmospheres. In contrast, the pressure differential between the high pressure vessel 55 and the low pressure vessel 57 in the fluid circuit 41 associated with the lowermost pipe cluster 30b is about 10 Atmospheres.

The pressure within the high pressure vessel 55 regulates the temperature at *which the water contained within the heat exchangers 21, 22 changes into steam. Water within the pipe clusters 30 of each heat exchanger changes from a liquid state to a gaseous state (steam) at different temperature levels. The actual temperature at which this change of state occurs varies between the pipe clusters 30 according to the differing constant pressures within the respective .high pressure vessel 55. This is because the various pipe clusters 30 in each heat exchanger 21, 22 are exposed to different temperatures in the heat chamber 12, according to their relative position within the heat exchanger. For example, pipe clusters 30 in the lower levels of each heat exchanger 21, 22 are exposed to a temperature ranges which overall are lower than the temperature -11ranges to which pipe clusters higher in the heat exchanger are exposed. This is because of the temperature gradient in the heat chamber 12.

The actual temperature range within which the water in each pipe cluster operates is about 600C, apart from the uppermost pipe cluster 30a. The uppermost pipe cluster 30a reciprocate between temperature levels within the heat chamber 12 from about 2500C to 4000C. The corresponding temperature range in which water in the uppermost pipe cluster 30a operates in from about 3200C to 3750C. In other words, the temperature of water in the uppermost pipe cluster 30a rises to about 3750C as a consequence of the pipe cluster entering the 4000C zone in the heat chamber, and falls to about 3200C as a consequence of the pipe cluster 30a entering the lowermost temperature to which it is exposed, being about the 2500C temperature zone. Accordingly, the water in the uppermost pipe cluster 30a operates within a temperature range of about In contrast, the pressure within the low pressure vessel 57 does not have to be regulated in a similar manner, as pressure therein is automatically regulated.

The regulation depends on the extent to which the water within the heat exchangers cools. If the water does not cool down to the extent that its pressure is the same as the pressure occurring within the low pressure vessel 57, then more water enters into vessel 57 through the constant operation of the hydraulic ram 71, thereby increasing the resultant pressure within vessel 57. Once the pressure increase equals the pressure prevailing within the heat exchangers, a%.

the heat exchangers commence filling with water from the low pressure vessel 57.

Each fluid circuit 41 contains working fluid which, as previously mentioned, is in the form of water. The water is caused to change between gaseous and liquid states as a result of absorbing and discharging heat.

The cycle through which the water passes in functioning as the working fluid will now be described in more detail. The description will be made with particular

I

-12reference to Figure 1 in relation to piper cluster 30a within heat exchanger 21 which is shown at its lowermost position within the heat chamber 12. From this position, the heat exchanger 21 ascends within the heat exchanger 12 by virtue of rocking motion of the rocker arm 15 about pivot 19. As the heat exchanger 21 ascends within the heat chamber 12, the pipe clusters 30a is exposed to the progressively increasing temperature gradient within the heat fluid contained in the heat chamber. Accordingly, the water within the fluid circuit 41a is heated, primarily in the pipes 31. The water within the pipes 31 achieves its boiling point and enters its gaseous state (steam). As the pipes 31 are closed at ends 32, and because those ends are elevated, the water in its gaseous state rises to the ends 32 of the pipes where it is trapped. As the water moves into its gaseous state, there is an increase in volume and pressure which causes an overall expansion of the water. Consequently, water is pushed out of the pipes 31 and into the upper end of the first (upper) internal reservoir 51. While the water which is pushed into the first internal reservoir 51 is heated, it is not in the gaseous state. Only water in a liquid state enters the reservoir 51. The entry of water into the upper end of the first (upper) internal reservoir 51 causes a corresponding volume of water contained therein to be expelled from the lower end of the reservoir 51. Because of the temperature gradient of the water in the first (upper) internal reservoir 51, the water expelled from the lower end is at a lower temperature that the water entering the upper end. The expulsion of water from the first (upper) internal reservoir 51 causes a corresponding volume of water to enter the upper end of the second (lower) internal reservoir 52, which in turn causes a similarly corresponding volume of water to be expelled from the lower end of the second (lower) internal reservoir. For similar reasons as S: explained in relation to the first (upper) internal reservoir 51, water expelled from the lower end of the second (lower) internal reservoir 52 is at a lower temperature than that which enters through the upper end. The overall S. expansion of the water is transferred through fluid flow line 61 to high pressure vessel 55 which is maintained at a generally constant pressure by the source 68 •of compressed air.

II

-13- Because the fluid circuit 41a incorporates the two reservoirs 51, 52, water leaving the heat chamber 12 along the flow line 61 is at a temperature close to ambient temperature which exists at the lowermost region of the heat chamber.

Accordingly, heat loss from the heat chamber is minimised.

The expansion of the water continues while the heat exchanger 21 ascends within the heat chamber 12. After the heat exchanger 21 has reached its uppermost position, it reverses in direction and commences to descend. In its descent, the heat exchanger 21 progressively moves downwardly through the decreasing temperature gradient within the heat chamber 12. As the pipes 31 move through a progressively cooler environment, they discharge heat and this results in condensation of the gaseous state of the water within the pipes. As the water condenses, a region of low pressure is created which causes water to be drawn back into the pipes 31. Consequently, water is drawn into the manifold 34 and pipes 31 from the first (upper) internal reservoir 51. The temperature gradient in the first (upper) internal reservoir 51 ensures that the warmest water contained therein is delivered to the manifold 34. This is beneficial for efficiency of the subsequent heating stage. Similarly, water is drawn from the second internal reservoir 52 into the first internal reservoir 51. Again, the warmest water contained therein is returned. This in turn causes water to be drawn from the 20 low pressure vessel 57 into the second internal reservoir 52.

.As mentioned previously, the pressure differential between the two pressure @006 vessels 55 and 57 is used to operate the hydraulic ram 71. With this arrangement, water is delivered alternately to the two operating chambers 72, 73 from the high pressure vessel 55 in timed sequence under the control of the intake control valves 75. Water is delivered to each chamber 72, 73 at a relatively high pressure to cause operation. The water in the hydraulic ram is eioe subsequently discharged at a relatively low pressure through the discharge circuit 76 under the control of the discharge valves 77. In this way, the high pressure vessel 55 and the low pressure 57 each communicate with the i 30 operating chambers 72, 73 of the hydraulic ram in sequence whereby water from -14the high pressure vessel can alternately enter each operating chamber of the hydraulic ram to cause the ram to undergo a stroke and whereby the spent water in the other operating chamber discharges to the low pressure vessel 57 during that stroke. Consequently, the water passes through a circuit from the high pressure vessel 55, to the hydraulic ram 71, and then to the low pressure vessel 57 from where it is then returned to the second internal reservoir 52, as previously described.

The fluid circuits 41 for all the pipe clusters 30 in the heat exchangers 21, 22 are of a similar arrangement to that for pipe cluster 30a, with the exception of the fluid circuit 41b for the lowermost pipe cluster The fluid circuit 41b for the lowermost pipe cluster 30b is similar to the circuit 41a with the exception that the low pressure vessel 57b is open to atmosphere.

As previously mentioned, each pipe cluster 30 has its own fluid circuit 41 and hydraulic ram 71. The various hydraulic rams 71 can be arranged to co-operate to deliver work to a common source if desired.

While any suitable arrangement can be used to establish the temperature gradient within the heat chamber 12, in this embodiment compression of the heat fluid (air) is utilised. A conventional air compressor would in all probability not, however, be able to withstand the high temperatures involved. A system capable of operating in such an arduous environment is therefore required. One such system is a heating means 27 which has been designed for the purpose and which is illustrated in Figure 4 of the drawings.

The heating means 27 utilises compression of the heat fluid (which in this embodiment is air) to generate heat therein. In this regard, the heating means 27 comprises two pressure vessels 80 located within the heat chamber 12.

Each pressure vessel 80 defines a pressure chamber 81, the bottom end of S"which communicates with a compressor system 85 located exteriorly of the heat chamber. The compressor system 85 includes two further pressure vessels 86 each of which communicates with a respective one of the pressure vessels As can be seen from Figure 4, each further pressure vessel 86 is shorter in length than its corresponding pressure vessel 80. The compressor system also includes a piston-type compressor 88.

The compressor system 85 contains a compression liquid which comprises a high-temperature-resistant, incompressible fluid. A particularly suitable compression fluid is Hitec dilution fluid.

The pressure chamber 81 contains compression fluid in the lower region 81a thereof and heat fluid (air) in the upper region 81b thereof. The compression fluid and the heat fluid are separated at an interface 82 therebetween. The compression fluid is delivered into the chamber 81 by way of the compressor system 85. The heat fluid within the chamber 12 is drawn from the upper region 81b of the interior 81 through an inlet 87 which incorporates a one-way valve, upon a suction stroke of the compressor system 85. The heat fluid contained within the interior 81 can be compressed upon delivery of compression fluid into the interior 81. The compression effects a rise in the temperature of the heat fluid. The compressed heat fluid is then delivered to a heat exchanger 90 which extends vertically within the heat chamber 12. As the heat fluid passes ***downwardly through the heat exchanger 90, it releases its heat and in doing so assists in maintaining the temperature gradient within the heat chamber 12. The compressed heat fluid discharges from the lower end of the heat exchanger and is diverted for further use. The diverted heat fluid may, for example, be employed as a heat source for other purposes. Alternatively, the diverted heat -fluid may be conveyed to a system (not shown), such as a turbine, through which energy in the compressed heat fluid (air) can be extracted as useful work.

The temperature of the compressed heat fluid leaving the heat chamber 12 is typically 50 100 0 C higher than the temperature of the cold air entering the heat chamber. The actual temperature of the compressed heat fluid (air) is dependent upon the extent the heat fluid is compressed by the compressor system 85. The excess heat in the heat fluid needs to be extracted from the -16heat fluid before the compressed heat fluid is directed onto the turbine. This provides several advantages, one of which is that the extracted heat may be utilised for other purposes, as appropriate. Another advantage is that the cooler compressed heat fluid (air) will exit from the turbine in an even cooler condition (typically below 0 0 C) and can therefore be used for cooling purposes.

The heat fluid diverted from the lower end of the heat exchanger 90 is lost from the heat chamber 12 and so is replaced with fresh heat fluid (in the form of ambient air) introduced into the lower-most region of the heat chamber 12. The incoming ambient air is at ambient temperature and so assists in maintaining the specified temperature gradient in the heat chamber 12.

In this embodiment, the heating means 27 utilised compression of the heat fluid (air) to generate heat used to establish and maintain the temperature gradient in the heat chamber. Where another form of heat source, which does not utilise compression of the heat fluid (air), is used to establish and maintain the temperature gradient in the heat chamber, it will nevertheless be necessary for compression of some heat fluid (air) in the uppermost zone of the heat chamber 12 to occur. The compression is not, however, required to the same extent, as the compression is not required for heat generation. The purpose of the *compression of the high temperature heat fluid (air) in the uppermost zone of the 20 heat chamber 12 is to accommodate entry of cold air into the lowermost region of the heat chamber 12. The entry of cold air into the heat chamber 12 serves to cool the lowermost region of the heat chamber, thereby assisting in maintenance of the temperature gradient, as previously mentioned. Furthermore, the incoming cold air causes hot air to migrate upwardly within the heat chamber.

25 The incoming cold air transfers a certain amount of heat into the heat chamber 12. By way of example, if the air entering the heat chamber 12 is at a temperature of 200C, it contains an additional 4.8 kilocalories of heat than it contained at the 00C. As the air ascends, it absorbs heat from the surroundings.

By the time it reaches the uppermost zone, which is at about 4000C, the air -17contains an additional 91.2 kilocalories of heat per kilogram than it did at the 200C temperature level. Altogether, the additional heat is 96 kilocalories per kilogram of air. Through compression of the air in the compression system that heat quantity is transferred from the 4000C to the 5000C temperature level, but the quantity of heat does not change. Because the air is at a 1000C higher temperature level, heat contained therein is discharged to the surroundings within the heat chamber 12 as the air descends in the heat exchanger 90. By the time it cools down to the temperature of 1200C, the air contains the same quantity of heat per kilogram as is contained within the replenishment air entering the heat chamber from outside (because if the compressed air was allowed to attain the same pressure as the pressure of the incoming air, then its temperature would also be the same as that of the outside air).

It is difficult to calculate exactly what occurs during air compression, as air at temperature levels below 00C also contains heat. Indeed, it is believed that vast amounts of heat are held at temperatures below 0°K in a concealed/latent form.

The reality is that the compressed air at the 4000C temperature level holds an additional 96 kilocalories of heat per kilogram to that held by air at 0°C, which large quantity of heat never leaves the heat chamber. Rather it moves up and down within the heat chamber, by the incoming air moving it upwardly and the 20 compressed hot air moving it downwardly. The same quantity of heat will •e.e•i therefore be continuously reused. This is a unique aspect of the present heat engine in comparison to conventional heat engines.

The drive system 26 provided to swing the rocker arms 15 back and forth is illustrated in Figure 3 of the drawings. The drive system 26 comprises a weight 25 and pulley system 100 associated with each rocker arm eeee Each weight and pulley system 100 comprises two containers 101, 102 positioned outside of the heat chamber 12 at opposed ends 15a, 15b of the respective rocker arm 15. Each container 101, 102 accommodates a weighted float structure 103 in the form of an inner container filled with water. A cable -18and pulley arrangement 105 operatively connects each weighted float structure 103 to the rocker arm A pump system 107 is provided for selectively transferring water from one of the containers 101, 102 to the other, so causing the weighted float structure 103 in the particular container 101, 102 into which water is delivered to become buoyant and rise, and the weighted float structure 103 in the particular container 101, 102 from which water is extracted to fall under the influence of gravity. This has the effect of causing one weighted float structure 103 to rise while the other falls (and vice versa) in a reciprocating fashion. The reciprocating movement of the two weighted float structures 103 is transferred to the respective rocker arm through the cable and pulley arrangement 105, so causing the rocker arm to rock back and forth about pivot axis 19. The rate of the rocking action of the rocker arm 15 is regulated by the rate at which water is transferred between the two containers 101, 102.

Some of the work delivered by the hydraulic rams may also be utilised to operate the drive system for the rocker structure 13, if desired.

From the foregoing it is evident that the present invention provides a simple yet highly effective arrangement for utilising heat to perform work. A typical advantage of the heat engine according to the invention is that heat losses are minimised in comparison to conventional heat engines. This advantage is achieved by ensuring that a significant part of heat energy which is delivered to the working fluid to change state from its liquid form to its gaseous form to generate pressure for subsequent operation of the hydraulic ram 71 does not leave the heat chamber with the working fluid. Accordingly, heat energy is not 25 wasted, as is the case with conventional heat engines as previously discussed.

Because there is no significant heat loss from the heat chamber, heat energy in the heat chamber can be constantly and continuously re-used. This provides significant benefits in terms of the efficient use of rapidly depleting fossil fuels available to mankind.

-19- Moreover, the heat engine according to the invention does not require the use of high quality fuel, because the heat chamber 12 never requires heating above a temperature of about 400 0 C (being the temperature established at the uppermost zone). Furthermore, a relatively minimal amount of heat is required to replenish heat losses, as useful work delivered by the heat engine is not generated from external heat energy input (as is the case with conventional heat engines), but rather from the heat energy contained within the heat chamber.

Heat energy initially invested in the heat chamber prior to the start up of the heat engine remains continuously therein, with minimal replenishment required to maintain continuous operation. Since there is no need for the establishment of a high temperature gradient environment through every cycle (as is the case with conventional heat engines), and as only minimal heat replenishment is needed, use of the rapidly depleting fossil fuels can be avoided. The amount of heat energy required could, for example, easily be provided by combustion of methane gas generated from a mixture of decomposing and sewage. By this means, the ever-increasing problem of sewage and rubbish disposal could also be resolved.

It should be appreciated that the scope of the invention is not limited to the scope of the particular embodiment described.

20 Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims (24)

1. A heat engine comprising: means for establishing a temperature gradient between two spaced apart zones within a heat chamber; a first fluid circuit at least in part moveable between the two spaced apart zones and adapted to contain a working fluid which, when in part of the first fluid circuit, expands and contracts on movement of the first fluid circuit between the two zones so as to perform work; and displacement means for moving the first fluid circuit between the two spaced apart zones so as to provide for the reciprocal generation of work.

2. A heat engine according to claim 1 comprising a second fluid circuit also at least in part moveable between the two spaced apart zones and adapted to contain a working fluid which, when in part of the second fluid circuit, expands and contracts on movement of the second fluid circuit between the two zones so as to perform work, the displacement means for moving the first and second fluid circuits between the two spaced apart zones so as to provide for the reciprocal generation of work.

3. A heat engine according to claim 2 wherein the first and second fluid circuits ev are connected. ::eve

4. A heat engine according to claim 3 wherein working fluid in each fluid circuit flows out of, and returns to, the heat chamber during the expansion and ee: contraction stages is in a liquid state.

5. A heat engine according to any one of claims 2 to 4, wherein the heat ::chamber is adapted to contain a heat fluid that provides the temperature gradient between the two spaced apart zones, and the parts of the first and second fluid circuits are respectively provided in first and second heat S0 exchangers adapted for reciprocatory movement within the heat chamber in opposed relation between the two spaced apart zones whereby one heat -21 exchanger moves towards one of said zones while the other heat exchanger moves towards the other of said zones.

6. A heat engine according to claim 5 wherein the heat fluid comprises a high temperature resistant fluid such as air or nitrogen.

7. A heat engine according to claim 5 or 6 wherein as part of the first and second fluid circuits the heat engine circuit includes a high pressure reservoir and a low pressure reservoir, both of which are located outside of the heat chamber, the fluid circuits being arranged to deliver working fluid upon expansion thereof to the high pressure reservoir and to return working fluid upon contraction thereof from the low pressure reservoir, the pressure differential in the two reservoirs being utilised to generate the work.

8. A heat engine according to claim 7 wherein the high pressure reservoir is maintained at a substantially constant pressure.

9. A heat engine according to any one of claims 5 to 8 wherein the working fluid performs work upon expansion thereof by acting on a hydraulic ram at said location outside of the heat chamber. A heat engine according to claim 9 wherein the hydraulic ram is of the double-acting type having two operating chambers separated by a piston, wherein working fluid is delivered alternatively to the two operating chambers in timed sequence and wherein working fluid is delivered to each .chamber at a relatively high pressure to cause operation of the hydraulic ram and is subsequently discharged at a relatively low pressure. 0"0.11. A heat engine according to any one of claims 5 to 10 wherein each fluid circuit further includes at least one internal reservoir which is located within 25 the heat chamber and which receives the working fluid.

12. A heat engine according to claim 11 wherein there are two of said internal reservoirs, one of which is located in close proximity to the respective heat -22- exchanger and moves in unison therewith, and the other of which is located in a region of the heat chamber corresponding to the low temperature end of the temperature gradient.

13. A heat engine according to claim 12 wherein the two internal reservoirs contain the working fluid in its liquid form.

14. A heat engine according to any one of claims 5 to 13, wherein the first and second heat exchangers each comprise a plurality of pipes arranged in a cluster, one end of each pipe being closed and the other end of each pipe communicating with a manifold forming part of the respective fluid circuit.

15. A heat engine according to claim 14 wherein the pipes in each cluster are positioned in side-by-side relationship and the manifold is disposed in a generally horizontal plane.

16. A heat engine according to claim 14 or 15 wherein the pipes are so positioned that the closed end thereof is uppermost when the heat chamber is at the extent of its movement towards the zone of higher temperature within the heat chamber.

17. A heat engine according to any one of claims 1 to 16 wherein each fluid ~ciCircuit includes a flexible portion to accommodate movement between the two zones within the heat chamber.

18. A heat engine according to any one of claims 5 to 16 wherein each heat 0. exchanger is mounted on a rocker assembly adapted for limited pivotal movement about a horizontal pivot axis, each exchanger being disposed to •i *one side of the pivot axis whereby one heat exchanger is caused to ascend within the heat chamber while the other heat exchanger descends, and vice 25 versa. 23

19. A heat engine according to any one of claims 1 to 18 wherein the temperature gradient within the heat chamber is maintained between about 400 0 C and ambient temperature. A heat engine according to any one of claims 1 to 19 wherein engine comprises heating means for establishing a temperature gradient in the heat chamber between the two spaced apart zones within the heat chamber.

21. A heat engine according to claim 20 wherein the heating means utilises compression of the heat fluid to generate heat therein.

22. A heat engine according to claim 19 or 21 wherein the heating means extracts heat fluid from at or near the uppermost zone of the heat chamber and subjects the extracted heat fluid to compression to generate heat therein, the heated heat fluid subsequently being conveyed downwardly along a flow path separate from but in heat exchange relationship with the heat chamber to deliver heat thereto.

23. A heat engine according to claim 22 wherein the extracted heat fluid after passing in heat exchange relationship with the heat chamber is diverted to a location remote from the heat chamber for further use.

24. A heat engine according to claim 23 wherein the extracted heat fluid is delivered to a system such as a turbine at which energy in the heat fluid can be extracted as useful work. *l .'0025. A heat engine according to claim 24 wherein excess heat in the heat fluid is extracted therefrom prior to delivery of the heat fluid to said system.

26. A heat engine according to any one of claims 22 to 25 wherein replacement lO.•.heat fluid at ambient temperature is delivered into the heat chamber at or 25 near the lowermost region thereof to replace the extracted heat fluid. -24-

27. A heat engine according to any one of the preceding claims wherein the working fluid comprises water.

28. A heat engine substantially as herein described with reference to the accompanying drawings. Dated this Twentieth day of May 2004. Stephen Lanyi Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant oo *o