Heat ejection system

Abstract

A heat ejection system (100) for use in vacuum and / or microgravity environment, having a first scissor mechanism (10), the first scissor mechanism having a first heat pipe (12), a first heat-emitting body (22), the first heat-emitting body being connected to, and in thermal contact with, the first heat pipe, wherein the first scissor mechanism is arranged so as to be extendable within a first plane from a compact configuration to an extended configuration, with the first heat pipe being configured to be contactable with a heat source (20) such that heat can flow from the heat source to the first heat pipe at least when the scissor mechanism is in its extended configuration, and then from the first heat pipe into the first heat-emitting body.

Description

[0001] Heat ejection system

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to a heat rejection mechanism that is suitable for use in a vacuum and / or microgravity environment.

[0004] BACKGROUND

[0005] Power sources generally create heat, if not as a primary product, then as a by-product. On Earth, excess heat can be conducted or convected away by water or air - large thermal bodies capable of absorbing such heat loads. In space, or on the moon, where there is no atmosphere, an alternative means for removing unwanted heat from a system, such as a power supply system, is required, at least in order to prevent the power supply system from overheating. These means must be capable of surviving the rigours of launch, the space environment, and possibly the landing process too.

[0006] SUMMARY

[0007] The present disclosure provides a heat ejection system as set out in claim 1 , a nuclear microreactor as set out in claim 10, a satellite as set out in claim 11 , and a power supply unit as set out in claim 12. Optional features are included in the dependent claims.

[0008] There is disclosed herein a heat ejection system for use in vacuum and / or microgravity environment, comprising a first scissor mechanism, the first scissor mechanism comprising a first heat pipe, a first heat-emitting body, the first heatemitting body being connected to, and in thermal contact with, the first heat pipe, wherein the first scissor mechanism is arranged so as to be extendable within a first plane from a compact configuration to an extended configuration, with the first heat pipe being configured to be contactable with a heat source such that heat can flow from the heat source to the first heat pipe at least when the scissor mechanism is in its extended configuration, and then from the first heat pipe into the first heat-emitting body.

[0009] By incorporating heat pipes into a scissor mechanism as a means of positioning a heat-emitting body for the ejection of heat from a system, there is no need for a fluid tube cooling circuit of the sort used in prior art systems, leading to a more robust heat ejection system better able to withstand harsh environmental conditions.

[0010] The first scissor mechanism of the heat ejection system can further comprise a second heat pipe, the second heat pipe being configured to be contactable with the heat source, such that heat can flow from the heat source to the second heat pipe at least when the scissor mechanism is in its extended configuration, and the second heat pipe can be connected to, and in thermal contact with, a second heat-emitting body, such that heat can flow from the second heat pipe into the second heatemitting body.

[0011] By adding a second heat pipe, an additional heat-emitting body can be added to the system, increasing the rate at which the system can eject heat.

[0012] The first scissor mechanism of the heat ejection system can further comprise one or more additional heat pipes, the one or more additional heat pipes being connected in series with either the first heat pipe or the second heat pipe so as to form a first and / or a second chain of heat pipes within the first scissor mechanism, and one or more additional heat-emitting bodies, each additional heat-emitting body being connected to, and in thermal contact with, one of the additional heat pipes, such that heat can travel along one of the first and / or second chain of heat pipes from the heat source and into at least one of the first heat-emitting body, the second heat-emitting body, and / or one of the additional heat-emitting bodies.

[0013] By adding additional heat pipes, additional heat-emitting bodies can be added to the system, increasing the rate at which the system can eject heat. At least one of the first heat-emitting body, the second heat-emitting body, or one of the additional heat-emitting bodies can comprise one or more further heat pipes, or one or more a fluid-filled conduits. By incorporating further heat pipes or a fluid-filled conduit into at least one of the heat-emitting bodies, heat will be more quickly distributed across the heat-emitting body.

[0014] At least one of the first heat-emitting body, the second heat-emitting body, or one of the additional heat-emitting bodies can comprise a monolithic block. A monolithic block is a durable, cheap and easy to manufacture means for ejecting heat from the system.

[0015] The heat ejection system can further comprise a second scissor mechanism, the second scissor mechanism comprising a third heat pipe, a third heat-emitting body, the third heat-emitting body being connected to, and in thermal contact with, the third heat pipe, wherein the second scissor mechanism is arranged so as to be extendable within a second plane parallel to the first plane from a compact configuration to an extended configuration, with the third heat pipe being configured to be contactable with the heat source such that heat can flow from the heat source to the third heat pipe at least when the scissor mechanism is in its extended configuration, and then from the third heat pipe into the third heat-emitting body, the heat ejection system further comprising one or more connecting elements extending between the first scissor mechanism and the second scissor mechanism.

[0016] By including a second scissor mechanism comprising a third heat pipe, and connecting the first and second scissor mechanisms, the structural rigidity of the heat ejection system is improved, and the capacity to eject heat from the system is increased.

[0017] The second scissor mechanism can further comprise a fourth heat pipe, the fourth heat pipe being configured to be contactable with the heat source, such that heat can flow from the heat source to the fourth heat pipe at least when the scissor mechanism is in its extended configuration, and one or more further additional heat pipes, the one or more further additional heat pipes being connected in series with either the third heat pipe or the fourth heat pipe so as to form a third and / or a fourth chain of heat pipes within the second scissor mechanism, and the heat ejection system further comprises one or more further additional heat-emitting bodies, each further additional heat-emitting body being connected to, and in thermal contact with, one of the further additional heat pipes, such that heat can travel along one of the third and / or fourth chain of heat pipes from the heat source and into at least one of the third heat-emitting body, and / or one of the additional heat-emitting bodies.

[0018] The additional of the fourth heat pipe and further additional heat-emitting bodies increases the capacity of the system to eject heat.

[0019] At least one of the one or more connecting elements can be a connecting heatemitting body. Having one or more of the connecting elements be a heat-emitting body increases the capacity of the system to eject heat whilst also providing improved structural rigidity.

[0020] There is also disclosed herein a nuclear microreactor comprising a heat ejection system disclosed herein. Such a nuclear microreactor benefits from the improvements to robustness of the heat ejection system that is capable of being transported to its deployment location in a more compact, transportable form, and then extended into a working configuration once at the deployment location.

[0021] There is also disclosed herein a satellite comprising the heat ejection system disclosed herein. Such a satellite benefits from the improvements to robustness of the heat ejection system that can be more readily placed into the limited volume of a cargo bay in a more compact, transportable form, and then extended into a working configuration once deployed in space.

[0022] There is also disclosed herein a power supply unit comprising the heat ejection system disclosed herein. Such a power supply unit benefits from the improvements to robustness of the heat ejection system that is capable of being transported to its deployment location in a more compact, transportable form, and then extended into a working configuration once at the deployment location. The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the above aspects may be applied mutatis mutandis to any other aspect. Furthermore except where mutually exclusive any feature described herein may be applied to any aspect and / or combined with any other feature described herein.

[0023] BRIEF DISCRIPTION OF THE DRAWINGS

[0024] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0025] Figure 1 is a schematic side view of a first scissor mechanism in a compact configuration;

[0026] Figure 2 is a schematic side view of the first scissor mechanism part-way between its compact and extended configurations;

[0027] Figure 3 is a schematic side view of the first scissor mechanism in its extended configuration;

[0028] Figure 4 is an isometric schematic view of a heat ejection system;

[0029] Figure 5 is a plan schematic view of a heat ejection system;

[0030] Figure 6 is an isometric schematic view of a further heat ejection system;

[0031] Figure 7 is a plan schematic view of a further heat ejection system;

[0032] Figure 8 is an isometric schematic view of a further heat ejection system;

[0033] Figure 9 is a plan schematic view of a further heat ejection system;

[0034] Figure 10 is an isometric schematic view of a further heat ejection system;

[0035] Figure 11 is a plan schematic view of a further heat ejection system; Figure 12 is a plan schematic view of a heat-emitting body;

[0036] Figure 13 is a plan schematic view of a further heat-emitting body;

[0037] Figure 14 is a plan schematic view of a further heat-emitting body;

[0038] Figure 15 is an isometric schematic view of a further heat ejection system;

[0039] Figure 16 is a plan schematic view of a further heat ejection system;

[0040] Figure 17 is an isometric schematic view of a further heat ejection system;

[0041] Figure 18 is a plan schematic view of a further heat ejection system;

[0042] Figure 19 is an isometric schematic view of a further heat ejection system;

[0043] Figure 20 is a plan schematic view of a further heat ejection system;

[0044] Figure 21 is an isometric schematic view of a further heat ejection system;

[0045] Figure 22 is a plan schematic view of a further heat ejection system;

[0046] Figure 23 is an isometric schematic view of a nuclear microreactor;

[0047] Figure 24 is an isometric schematic view of a satellite; and

[0048] Figure 25 is an isometric schematic view of a power supply unit.

[0049] DETAILED DESCRIPTION

[0050] Aspects and embodiments of the present disclosure will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.

[0051] Figure 1 shows a schematic side view of a first scissor mechanism 10 of a heat ejection system 100 according to the present disclosure in a first, compact, configuration. The skilled person will be familiar with such a scissor mechanism, which is comprised of a number of struts connected together in two criss-crossing series of struts, so that, when (for example) a force is exerted to bring together the two struts at one end of the scissor mechanism, the interior angle made between the struts of the two criss-crossing series is reduced, and the scissor mechanism becomes elongated - i.e. , within a single plane it extends from a compact configuration to an extended configuration (see Figures 2 and 3). A drive mechanism 18 is provided to move the heat ejection system from its compact configuration to its extended configuration. The types of drive mechanism suitable for moving the heat ejection system from its compact configuration to its extended configuration will be readily apparent to the skilled person, and as such no further detail will be given in regard to this feature. The compact configuration shown in Figure 1 would be suitable for when, as an example, the heat ejection system requires stowing away for transport, or fitting in to the cargo bay of a space rocket or shuttle.

[0052] In the example scissor mechanism 10 of Figure 1 , the first strut, which is to say the strut closest to a heat source, of one of the series of struts making up the scissor mechanism, is a heat pipe 12 (indicated in Figure 1 and all the following figures by dotted hatching). Heat pipes will be familiar to the person skilled in the art as a means for transporting heat using a combination of conduction and convection from one location to another. A heat pipe has a hot end in which the working fluid sealed within the heat pipe undergoes vaporisation, and a condenser section extending from the other end in which the working fluid condenses, warming the cooler end of the heat pipe, before returning via capillary action back to the hot end of the heat pipe, to begin the process again.

[0053] In figures showing the heat ejection system 100, the heat ejection system 100 is shown mounted to an object 200 which contains at least a heat source 20. The heat pipe 12 is in thermal contact with the heat source 20, which is to say that heat can be transferred from the heat source 20 to the heat pipe at least via conduction.

[0054] The remaining struts of the scissor mechanism 10 can be made of any suitable construction capable of fulfilling the mechanical requirements of the role. For example, the remaining struts of this example scissor mechanism may consist of simple bars or rods made of stainless steel, titanium, or other suitable material.

[0055] Figure 2 shows a schematic side view of the first scissor mechanism 10 of Figure 1 part-way between its compact and extended configurations. As the two struts at one end of the scissor mechanism are brought together, the interior angle made between the struts of the two criss-crossing series is reduced, and the scissor mechanism starts to elongate.

[0056] Figure 3 shows a schematic side view of the first scissor mechanism 10 of Figure 1 in its extended configuration, i.e. the configuration of the first scissor mechanism 10 when the heat ejection system 100 is optimised for rejecting heat. In Figures 1 , 2, and 3, one end of the first heat pipe 12 has been in contact with the heat source 20 in each of the compact, intermediate, and extended configurations, but it will be apparent to the skilled person that the heat ejection system may be arranged such that the first heat pipe 12 only comes into contact with the heat source 20 when the heat ejection system 100 is in its extended configuration, as it is likely the main usage of the heat ejection system will be when the heat ejection system is in its extended configuration.

[0057] Figure 4 shows an isometric schematic view, and Figure 5 shows a plan schematic view, of a heat ejection system 100 comprising a first scissor mechanism 10. In addition to the features already described with relation to the first scissor mechanism 10 shown in Figures 1 , 2, and 3, the heat ejection system 100 of Figures 4 and 5 further comprises a first heat-emitting body 22. The first heat-emitting body 22 is connected to, and in thermal contact with, the first heat pipe 12, which is to say that heat can be transferred from the first heat pipe 12 to the first heat-emitting body 22 via conduction at least.

[0058] The operation of the heat ejection system of Figures 4 and 5 in a vacuum and / or microgravity environment can be described as follows. First, heat from the heat source 20 travels at least via conduction into the first heat pipe 12. The heat is then conveyed along the first heat pipe and into the first heat-emitting body 22. After the heat is transferred into the first heat-emitting body, the heat can be radiated out from the heatemitting body into space. By having the scissor mechanism 10 of the heat ejection system 100 in an extended configuration during operation, the first heat-emitting body 22 is positioned as far from the object 200 as possible, and with the most surface area unobstructed by the object 200, therefore permitting the most heat to be radiated away from the first heat-emitting body 22 without being radiated back towards the object. The scissor mechanism therefore provides the advantage of allowing the heat ejection system 100 to adopt a compact form when it is being transported, before changing to an extended configuration when the heat ejection system 100 needs to be deployed.

[0059] Prior art heat ejection mechanisms have used fluid tube cooling circuits, which circulate a fluid medium from a heat source (such as a heat exchanger) out into radiative panels, from where the heat energy can be radiated away into space. A disadvantage of such systems is that if the cooling circuit springs a leak, the fluid medium will be lost, rendering the whole cooling system useless. By using heat pipes within the scissor mechanism as the means for transporting heat energy to the heatemitting body for the ejection of heat from a system, there is no need for a fluid tube cooling circuit, leading to a more robust heat ejection system better able to withstand harsh environmental conditions.

[0060] Figure 6 shows an isometric schematic view, and Figure 7 shows a plan schematic view, of a heat ejection system 100 where a strut of the scissor mechanism has been replaced with a second heat pipe 14. The second heat pipe, like the first heat pipe 12, is arranged to be in contact with the heat source 20 at least when the scissor mechanism is in its extended configuration, such that heat can flow from the heat source to the second heat pipe at least when the scissor mechanism is in its extended configuration. The second heat pipe 14 is connected to, and in thermal contact with, a second heat-emitting body 16 (shown in dashed outline in Figure 6 so as not to block the view of the first heat pipe 12 and heat source 20), such that heat can flow from the second heat pipe 14 into the second heat-emitting body 16. Generally the heat flow from the second heat pipe 14 into the second heat-emitting body 16 will be via conduction due to the physical contact between the second heat pipe 14 and the second heat-emitting body 16, either directly or via an intermediate component, although it is understood that, for example, some small amount a heat may also be transferred radiatively from the second heat pipe 14 into the second heat-emitting body 16, for example.

[0061] Having both struts of the first scissor mechanism 10 comprise heat pipes has the advantage that the second heat-emitting body can be added to the heat ejection system, thus increasing the total surface area of heat ejection and therefore the rate at which heat can be moved from the heat source 20 and ejected from the system.

[0062] Figure 8 shows an isometric schematic view, and Figure 9 shows a plan schematic view, of a heat ejection system 100 where the first scissor mechanism 10 further comprises two additional heat pipes 24. The two additional heat pipes 24 are connected in series with the first heat pipe 12 so as to form a chain of heat pipes within the first scissor mechanism 10. Additional struts have been added to the first scissor mechanism to support the additional heat pipes 24. The heat pipes 12, 24 of this chain of are rotatably connected to each other, such that, in a plane containing both the heat pipes, the angle between the heat pipes at the point where the heat pipes are connected can be varied. The connections between the heat pipes 12, 24 allow for heat to travel by at least conduction from one heat pipe into the next heat pipe. Therefore, heat can travel by at least conduction between heat pipes and convection within the heat pipes along the chain of heat pipes 12, 24 from one end of the chain of heat pipes, e.g. the end which is in contact with the heat source 20, to the other end of the chain of heat pipes; e.g. the furthest end of the last heat pipe in the chain, furthest from the heat source 20.

[0063] The heat ejection system 100 shown in Figures 8 and 9 also includes two additional heat-emitting bodies 28. Each of the additional heat-emitting bodies 28 is connected to, and in thermal contact with, one of the additional heat pipes 24, such that heat can travel along the first chain of heat pipes 12, 24 from the heat source 20 and into the first heat-emitting body 22 or one of the additional heat-emitting bodies 28.

[0064] It will be apparent that by increasing the length of the first scissor mechanism 10, additional heat pipes can be incorporated into the heat ejection system 100, and therefore additional heat-emitting bodies 28, leading to an increase in the potential surface area for radiative heat ejection, and therefore an increase in the rate at which heat can be ejected from the object 200 containing the heat source 20 in contact with the heat ejection system 100.

[0065] Given the heat ejection system 100 will usually be in the compact configuration when being transported or in storage, it is not essential that heat is able to travel along the chain of heat pipes when the first scissor mechanism 10 is in its compact configuration. However, the connections between the heat pipes in a chain must allow thermal transfer when the first scissor mechanism 10 is in its second, extended configuration, as it is in the extended configuration that the heat rejection system 100 is optimised for rejecting heat. In some applications, for example if the heat rejection mechanism is used as part of a satellite, it is unlikely the scissor mechanism will need to be collapsed back into its compact configuration again after having been deployed in its extended configuration. It is therefore not essential that the first scissor mechanism 10 is capable of returning to its compact configuration after use. So, for example, in some cases it would not be an issue if, after being deployed into its extended configuration, heat was allowed to flow down the chain of heat pipes, and this resulted in the chain of heat pipes becoming fused together and therefore the chain of heat pipes was no longer able to return to its compact configuration.

[0066] In order to achieve the transfer of heat along the chain of heat pipes from one end to the other, it is necessary to use a series of different working fluids within the heat pipes, such that the cold temperature end of one heat pipe is greater than the boiling point of the working fluid in the next heat pipe in the chain. For example, the first heat pipe 12 in the chain, which is in contact with the heat source 20, may be made of stainless steel or nickel, and have a working fluid of sodium. The second heat pipe in the chain, the hot end of which is in contact with the cold end of the first heat pipe, may be made of stainless steel, and have working fluid of mercury. The third heat pipe in the chain, the hot end of which is in contact with the cold end of the second heat pipe, may be made of titanium or stainless steel, and have working fluid of water. A fourth heat pipe could be added to the chain, with its hot end in contact with the cold end of the third heat pipe, being made of stainless steel or aluminium, and having a working fluid of ammonia, for example. In such a way, the cold end of one heat pipe is warm enough to boil the working fluid of the next heat pipe, and therefore allow the heat to pass along the first chain of heat pipes from a first end of the first chain of heat pipes to a second end of the first chain of heat pipes.

[0067] Figure 10 shows an isometric schematic view, and Figure 11 shows a plan schematic view, of a heat ejection system 100 where, compared to the heat ejection system of Figures 8 and 9, the first scissor mechanism 10 has more two additional heat pipes 24. The two extra additional heat pipes 24 are connected in series with the second heat pipe 14 so as to form a second chain of heat pipes within the first scissor mechanism 10. The heat pipes 14, 24 of this chain of are also rotatably connected, such that, in a plane containing both the heat pipes, the angle between the heat pipes at the point where the heat pipes are connected can be varied, as is required for a working scissor mechanism. The connections between the heat pipes 14, 24 also allow for heat to travel by at least conduction from one heat pipe into the next heat pipe. Therefore, heat can travel by at least conduction between heat pipes and convection within the heat pipes along the second chain of heat pipes 14, 24 from one end of the chain of heat pipes, e.g. the end which is in contact with the heat source 20, to the other end of the chain of heat pipes; e.g. the furthest end of the last heat pipe in the chain, furthest from the heat source 20.

[0068] The heat ejection system 100 shown in Figures 10 and 11 includes two more additional heat-emitting bodies 28 (which, with the second heat-emitting body 16, are shown in dashed outline in Figure 10 so as not to block the view of the first scissor mechanism 10). Each of the additional heat-emitting bodies 28 is connected to, and in thermal contact with, one of the additional heat pipes 24 of the second chain of heat pipes, such that heat can travel along the second chain of heat pipes 14, 24 from the heat source 20 and into the second heat-emitting body 16 or one of the additional heatemitting bodies 28.

[0069] It will be apparent that by incorporating further additional heat pipes into the first scissor mechanism 10, further additional heat-emitting bodies 28 can be added to the heat ejection system 100, leading to an increase in the potential surface area for radiative heat ejection, and therefore an increase in the rate at which heat can be ejected from the object 200 containing the heat source 20 in contact with the heat ejection system 100.

[0070] The heat ejection system 100 of Figures 10 and 11 also incorporates additional struts at the end of the heat pipe chains. It will be apparent to the skilled person that such additional struts will not affect the performance of the heat ejection system, but may serve to improve the structural rigidity of the first scissor mechanism. These additional struts may also incorporate heat pipes, and be in thermal contact with heat-emitting bodies, if desired,

[0071] The heat-emitting bodies 16, 22, 28 can take any form suitable for radiating away heat, and the skilled person will be familiar with some types of radiative panelling used on, for example, space satellites. Figures 12, 13, and 14 illustrate some schematic examples of further possible designs of heat-emitting body which could be used as part of the heat ejection system disclosed herein. In the example of Figure 12, the heat-emitting body comprises a number of further heat pipes 30. The further heat pipes 30 help transport the heat away from a region where the heat emitting body is in thermal contact with a heat pipe (an example of which indicated in Figures 12, 13, and 14 by the large arrow), and to spread the heat across the heat emitting body, so as to increase the rate at which heat spreads across the surface area of the heat emitting body from which heat is radiated away. Whilst the example shown in Figure 12 includes three further heat pipes 30, it will be appreciated that even just one further heat pipe 30 can help spread the heat across the heat emitting body. As such, the heat emitting body 16, 22, 28 can comprise one or more further heat pipes 30 to achieve an advantageous spread of heat across the heat emitting body.

[0072] In the example of Figure 13, the heat-emitting body 16, 22, 28 comprises a fluid-filled circuit 26. A fluid flow director 58, for example a pump or check valve, serves to keep the fluid flowing around the circuit in the same direction. A solar panel could be used to power the fluid flow director. The fluid-filled circuit serves the same purpose as the further heat pipes of the example heat-emitting body of Figure 12, which is to transport the heat away from the region where the heat emitting body is in thermal contact with a heat pipe, and to spread the heat across the heat emitting body, thus increasing the rate at which heat spreads across the surface area of the heat emitting body from which heat is radiated away. In this example, the fluid-filled circuit is formed into a closed loop, with the fluid being directed around the loop by the fluid flow director 58, so that the fluid can absorb the heat conducted to the fluid from the adjoining heat pipe, and transport it around the heat-emitting body from where it can be radiated away, such that by the time the fluid completes the loop and returns to the point where the heat-emitting body is in contact with the heat pipe, it has cooled down by releasing the heat energy into the surrounding body of the heat-emitting body, and is ready to absorb heat form the heat pipe again.

[0073] In the example of Figure 14, the heat-emitting body 16, 22, 28 comprises a monolithic block. Whilst the monolithic block may not be as efficient at transporting heat away from the region where the monolithic block is in thermal contact with a heat pipe, it is likely to be more durable, cheaper and easier to manufacture than the examples of Figures 12 and 13. Providing the monolithic block is of a material and size capable of transporting and radiating away the amount of heat required to be removed from the object 200, it will likely be the simplest and easiest means by which to achieve the required heat rejection.

[0074] Figure 15 shows an isometric schematic view, and Figure 16 shows a schematic plan view, of a further example of a heat rejection system 100 according to the present disclosure. The example system of Figures 15 and 16 comprises a second scissor mechanism 40. The second scissor mechanism 40 has a similar construction to the first scissor mechanism, in that is comprised of a number of struts connected together in two criss-crossing series of struts, so that, when a force is exerted to bring together the two struts at one end of the scissor mechanism, the interior angle made between the struts of the two criss-crossing series is reduced, and the scissor mechanism becomes elongated - i.e. within a single plane it extends from a compact configuration to an extended configuration.

[0075] The second scissor mechanism 40 includes a third heat pipe 34 and a third heatemitting body 36 (the third heat-emitting body being shown in dashed outline in Figure 15 so as not to block the view of the third heat pipe 34 and heat source 20). The third heat-emitting body 36 is connected to, and in thermal contact with, the third heat pipe 34, such that heat can flow from the third heat pipe 34 to the third heat-emitting body 36. The second scissor mechanism 40 is arranged so as to be extendable within a second plane parallel to the first plane (and therefore parallel to the plane in which the first scissor mechanism extends) from a compact configuration to an extended configuration. The third heat pipe being is arranged such that it is in contact with the heat source 20 at least when the scissor mechanism is in its extended configuration. When the third heat pipe is in contact with the heat source 20, heat can flow from the heat source to the third heat pipe 34, and then from the third heat pipe 34 into the third heat-emitting body 36.

[0076] The example heat ejection system 100 of Figures 15 an 16 also has four connecting elements 52 extending between the first scissor mechanism 10 and the second scissor mechanism 40. It will be apparent to the skilled person that such connecting elements will not affect the heat-ejecting performance of the heat ejection system, but rather serve at least to improve its structural rigidity. It will also be apparent to the skilled person that the number of connecting elements 52 can vary depending on the length of the first 10 and second 40 scissor mechanisms, which is dependent on the number of struts and heat pipes used in the construction of the first 10 and second 40 scissor mechanisms.

[0077] Figure 17 shows an isometric schematic view, and Figure 18 shows a schematic plan view, of a further example of a heat rejection system 100 according to the present disclosure. In the example system of Figures 17 and 18 the second scissor mechanism 40 includes a fourth heat pipe 38. The fourth heat pipe 38, like the third heat pipe 34, is arranged to be in contact with the heat source 20 at least when the scissor mechanism is in its extended configuration, such that heat can flow from the heat source to the fourth heat pipe.

[0078] In this example heat ejection system, one further additional heat pipe 44 has been added to the second scissor mechanism 40. In this example, the further additional heat pipe 44 is connected in series to the fourth heat pipe 38 so as to form a third chain of heat pipes, the third chain of heat pipes being within the second scissor mechanism.

[0079] In this example heat ejection system the further additional heat pipe 44 is connected to, and in thermal contact with, a further additional heat-emitting body 46 (shown in dashed outline in Figure 6 so as not to block the view of the third 34 and fourth 38 heat pipes and heat source 20), such that heat can flow from the fourth heat pipe 38 into the further additional heat pipe 44 and then into the further additional heat-emitting body 46. Generally the heat flow from the further additional heat pipe 44 into the fourth heat-emitting body 44 will be via conduction due to the physical contact between the further additional heat pipe 44 and the fourth heat-emitting body 44, either directly or via an intermediate component, although it is understood that, for example, some small amount a heat may also be transferred radiatively from the further additional heat pipe 44 into the fourth heat-emitting body 44, for example.

[0080] Figure 19 shows an isometric schematic view, and Figure 20 shows a schematic plan view, of a further example of a heat rejection system 100 according to the present disclosure. In the example system of Figures 19 and 20 the both the first scissor mechanism 10 and the second scissor mechanism 40 comprise chains of heat pipes, which is to say that additional heat pipes 24 are connected to both the first heat pipe 12 and the second heat pipe 14 within the first scissor mechanism, and further additional heat pipes 44 are connected to both the third heat pipe 34 and fourth heat pipe 38 within the second scissor mechanism.

[0081] As can be seen in Figures 19 and 20, the additional heat pipes 24 of the first scissor mechanism 10 allow for additional heat-emitting bodies to be mounted to the first scissor mechanism, as the heat from the heat source 20 can flow into the first 12 and second 14 heat pipes at least by conduction, and then either flow into the first heatemitting body (via the first heat pipe), or flow further down the chain of heat pipes and into one of the additional heat-emitting bodies 28, from where it can be radiated away from the heat ejection system.

[0082] A similar arrangement is present in the second scissor mechanism 40. Further additional heat pipes 44 are connected to both the third heat pipe 34 and the fourth heat pipe 38 within the second scissor mechanism 40. The further additional heat pipes 24 of the second scissor mechanism 40 allow for further additional heat-emitting bodies 46 to be mounted to the second scissor mechanism, as the heat from the heat source 20 can flow into the third 34 and fourth 38 heat pipes at least by conduction, and then either flow into the third heat-emitting body 36 (via the third heat pipe 34), or, via either the third or fourth heat pipes, flow further down the chains of heat pipes and into one of the further additional heat-emitting bodies 46, from where it can be radiated away from the heat ejection system.

[0083] Figure 21 shows an isometric schematic view, and Figure 22 shows a schematic plan view, of a further example of a heat rejection system 100 according to the present disclosure. In the example system of Figures 21 and 22, some of the connecting elements 52 are connecting heat-emitting bodies 54, which are in thermal contact with a least one of the heat pipes 12, 14, 24, 34, 38, 44 of either the first 10 or second 40 scissor mechanisms.

[0084] The connecting heat-emitting bodies, like the other heat-emitting bodies 16, 22, 28, 36, can take any suitable form that allows heat energy to be absorbed from a heat pipe and radiated away into space. Such forms include at least the illustrative examples of Figures 12, 13, and 14. Having the connecting elements 52 take the form of connecting heat-emitting bodies 54, when heat which flows from the heat source 20 into any of the first 12, second 14, third 34, or fourth 38 heat pipes, it can radiate directly into space from the heat pipe, or it can then travel into one of the first heat-emitting body 22, third heat-emitting body 36, or the first connecting heat-emitting body, or it could flow further down the chain of additional heat pipes 24 or further additional heat pipes 44 and into one of the additional heat-emitting bodies 28, further additional heat emitting bodies 46, or one of the other connecting heat-emitting bodies 54, from where it can be radiated away into space. Such a heat ejection system maximises the amount of radiative surface area available for ejecting heat transported from the heat source via the chains of heat pipes.

[0085] Figure 23 shows an isometric schematic view of a nuclear microreactor 48 comprising a heat ejection system 100. Heat generated within the nuclear microreactor 48 can be directed to the heat source 20 at an external surface of the nuclear microreactor so that it can then be extracted into the heat ejection system 100 and radiated away.

[0086] Figure 24 shows an isometric schematic view of a satellite 50 comprising the heat ejection system 100. Heat may be generated in the satellite 50 by a nuclear microreactor, or the heat may come from some other source. Heat generated within the satellite can be directed to the heat source 20 at an external surface of the satellite so that it can then be extracted into the heat ejection system 100 and radiated away.

[0087] In the heat ejection system of Figure 24, the heat pipes 12, 14, 24, 34, 38, 44 and struts of the first 10 and second 40 scissor mechanisms have joined so that the chains of heat pipes run parallel to each other, rather than crossing over each other. In other words, whereas in the previous examples, the heat pipes or struts of a given chain would alternate between being on the “inside” and the “outside” of the scissor mechanism, in Figure 24, all of the heat pipes and / or struts of one chain are on the “inside”, and all of the heat pipes and / or struts of the other chain are on the “outside” of the scissor mechanism. The skilled person will appreciate this option as to how the chains of heat pipes are arranged can be used as an alternative in any of the example heat ejection systems disclosed herein without affecting the performance of the systems.

[0088] Figure 25 shows an isometric schematic view of a power supply unit 56 comprising a heat ejection system 100. Such a power supply unit may be utilised at a lunar or Martian base or in other aspects of planetary exploration, for example. Heat may be generated in the power supply unit 56 by a nuclear microreactor, or the heat may come from some other source. Heat generated within the power supply unit can be directed to the heat source 20 at an external surface of the power supply unit so that it can then be extracted into the heat ejection system 100 and radiated away.

[0089] In the heat ejection system of Figure 25, the connecting heat-emitting body 54 is in the form of a flexible panel. The flexible panel can be connected between the first 10 and second 40 scissor mechanisms so as to unfurl as the first and second scissor mechanisms move from their compact configuration to their extended configuration. The skilled person will appreciate that one or more flexible panels could equally be used in other heat ejection systems such as those illustrated herein, including those comprising only a single scissor mechanism. In the case where one or more flexible panels are used with a single scissor mechanism, the folding panel can be supported by, for example, stiffened support members extending through the panel from points on the scissor mechanism. Using a flexible panel has the advantage that it provides even greater surface area from which heat can be radiated away from the system.

[0090] It will be understood that the invention is not limited to the embodiments abovedescribed and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

[0091] The skilled person will appreciate that the number of heat pipes and heat-emitting bodies can be varied according to the space available to deploy the heat rejection system, and the heat ejection requirements of the system. The examples shown here are purely illustrative of the principle that the of what can be achieved through the arrangement of heat pipes used in an expanding scissor mechanism combined with the radiative heat ejection of the heat-emitting bodies. The exact numbers of heat pipes and heat-emitting bodies shown in the examples should not be considered limiting, except to say that as per the example of Figure 4, at least one heat pipe and one heat-emitting body are required in order for the heat ejection system to function.

[0092] The skilled person will further appreciate that the various heat-emitting bodies illustrated herein which have the appearance of rigid panels could be replaced with folding or flexible panels to achieve the same effect. For example, the first 22, second 16, third 36, additional 28, or further additional 46 heat-emitting bodies may take the form of flexible or folding panels that are deployed into their operating condition as part of the deployment of the heat ejection system, and not be just rigid panels that are kept in a fixed position relative to the heat pipe they are connected to.

Claims

Claims1. A heat ejection system (100) for use in vacuum and / or microgravity environment, comprising: a first scissor mechanism (10), the first scissor mechanism comprising a first heat pipe (12); a first heat-emitting body (22), the first heat-emitting body being connected to, and in thermal contact with, the first heat pipe (12); wherein the first scissor mechanism (10) is arranged so as to be extendable within a first plane from a compact configuration to an extended configuration, with the first heat pipe being configured to be contactable with a heat source (20) such that heat can flow from the heat source to the first heat pipe at least when the scissor mechanism is in its extended configuration, and then from the first heat pipe into the first heat-emitting body (22).

2. The heat ejection system (100) of claim 1 , wherein the first scissor mechanism further comprises a second heat pipe (14), the second heat pipe being configured to be contactable with the heat source (20), such that heat can flow from the heat source to the second heat pipe at least when the scissor mechanism is in its extended configuration; the second heat pipe (14) being connected to, and in thermal contact with, a second heat-emitting body (16), such that heat can flow from the second heat pipe into the second heat-emitting body.

3. The heat ejection system (100) of any preceding claim, wherein the first scissor mechanism (10) further comprises: one or more additional heat pipes (24), the one or more additional heat pipes (24) being connected in series with either the first heat pipe (12) or the second heat pipe (14) so as to form a first and / or a second chain of heat pipes within the first scissor mechanism (10);One or more additional heat-emitting bodies (28), each additional heatemitting body being connected to, and in thermal contact with, one of the additional heat pipes (24), such that heat can travel along one of the first and / or second chain of heat pipes from the heat source (20) and into at least one of the first heat-emitting body (22), the second heat-emitting body (16), and / or one of the additional heat-emitting bodies (28).

4. The heat ejection system of any preceding claim, wherein at least one of the first heat-emitting body (22), the second heat-emitting body (16), or one of the additional heat-emitting bodies (28) comprises one or more further heat pipes (30).

5. The heat ejection system of any preceding claim, wherein at least one of the first heat-emitting body (22), the second heat-emitting body (16), or one of the additional heat-emitting bodies (28) comprises a fluid-filled circuit (26).

6. The heat ejection system of any preceding claim, wherein at least one of the first heat-emitting body (22), the second heat-emitting body (16), or one of the additional heat-emitting bodies (28) comprises a monolithic block (32).

7. The heat ejection system of any preceding claim, wherein the heat ejection system (100) further comprises a second scissor mechanism (40), the second scissor mechanism comprising; a third heat pipe (34); a third heat-emitting body (36), the third heat-emitting body being connected to, and in thermal contact with, the third heat pipe (34); wherein the second scissor mechanism (40) is arranged so as to be extendable within a second plane parallel to the first plane from a compact configuration to an extended configuration, with the third heat pipe being configured to be contactable with the heat source (20) such that heat can flow from the heat source to the third heat pipe (34) at least when the scissor mechanism is in its extended configuration, and then from the third heat pipe (34) into the third heat-emitting body (36);The heat ejection system (100) further comprising one or more connecting elements (52) extending between the first scissor mechanism and the second scissor mechanism.

8. The heat ejection system of claim 7, wherein the second scissor mechanism (40) further comprises: a fourth heat pipe (38), the fourth heat pipe (38) being configured to be contactable with the heat source (20), such that heat can flow from the heat source (20) to the fourth heat pipe (38) at least when the scissor mechanism is in its extended configuration; one or more further additional heat pipes (44), the one or more further additional heat pipes (44) being connected in series with either the third heat pipe (34) or the fourth heat pipe (38) so as to form a third and / or a fourth chain of heat pipes within the second scissor mechanism; and the heat ejection system further comprises one or more further additional heatemitting bodies (46), each further additional heat-emitting body being connected to, and in thermal contact with, one of the further additional heat pipes (44), such that heat can travel along one of the third and / or fourth chain of heat pipes from the heat source (20) and into at least one of the third heat-emitting body (36), and / or one of the additional heat-emitting bodies (46).

9. The heat ejection system of claim 7 or 8, wherein at least one of the one or more connecting elements (52) is a connecting heat-emitting body (54).

10. A nuclear microreactor (48) comprising the heat ejection system of any preceding claim.

11. A satellite (50) comprising the heat ejection system of any of claims 1-9.

12. A power supply unit (56) comprising the heat ejection system of any of claims 1 -9.

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