GB2621264A - Improvements to thermoelectric modules and assemblies - Google Patents

Abstract

An assembly comprising a first heat transfer plate having a first face and a second face, a first thermoelectric module having a first side and a second side, a second thermoelectric module having a first side and a second side, power supply circuitry, and control circuitry, wherein: the second side of the first thermoelectric module is thermally coupled to at least a portion of the first face of the first heat transfer plate; the first side of the second thermoelectric module is thermally coupled to at least a portion of the second face of the heat transfer plate; and the power supply circuitry and control circuitry are connected to the first and second thermoelectric modules so as to controllably supply electrical power to each thermoelectric module.

Description

Improvements to Thermoelectric Modules and Assemblies Field of the invention [1] The invention relates to thermoelectric modules and assemblies used for heating and cooling objects and/or substances, and reclaiming heat energy by converting it to electrical energy. In particular, it relates to more efficient heating and cooling, or energy reclamation, by thcusing a plurality of thermoelectric elements on the same object and/or substance.

Background of the invention

[2] Thermoelectric modules and assemblies are used as heat pumps to provide 10 cooling or heating in domestic, commercial and industrial applications.

[3] The use of thermoelectric modules and assemblies to transfer heat by the Peltier method (using thermoelectric coolers or TLCs), and generate power by the Seebeck method (using thermoelectric generators or TE(js), are well known and used in many applications. Thermoelectric modules and assemblies are incorporated into systems to transfer heat and generate/reclaim power.

[4] Applying a current to a thermoelectric device creates a heat flux (the Peltier effect), drawing heat from one side and radiating heat on the other side. Electrical energy is converted into heat energy with the semi-conductor components of the thermoelectric device acting as resistors.

[005] Thermoelectric modules and assemblies generally comprise: thermoelectric semi-conductors; thermally conducting plates; heat sinks; and sometimes fans. A typical thermoelectric module arrangement comprises semi-conductors placed between thermally conductive plates in an assembly with heat sinks mounted onto the thermoelectric elements, optionally with fans to increase the flow of fluids (e.g. air, water, etc.) across the heat sinks.

[006] Thermoelectric modules can operate individually, can be grouped together in stacks, or can form part of a system. Performance and operation varies according to a number of factors, such as the number of modules, the application and environment, variations in applied current Cm terms of both magnitude and direction), and any temperature differential across the modules. This allows for considerable flexibility of operation.

[0071 Typically, a controllable power source connected to the terminals of a thermoelectric device will pass an electrical current through the semi-conductors, which are arranged electrically in series to transfer heat across the thermoelectric device, resulting in a hot side and a cold side. Reversing the polarity of the electric current changes the direction of the heat transfer and reverses the hot side and the cold side.

19081 I leat transfer through a thermoelectric module or assembly is generally in a single direction, depending on the polarity of the applied voltage.

Summary of the Invention

10091 It is desirable to increase the magnitude and rate of heat transfer of 15 thermoelectric modules by focusing and intensifying thermal conduction.

[0101 The invention provides heat transfer plates and/or blocks for thermal contact with an object or substance to be heated or cooled, wherein said heating or cooling is caused by thermal contact with the heat transfer plate/block, which is itself heated or cooled. The heating or cooling of the heat transfer plate/block is caused by at least a portion of the heat transfer plate/block being sandwiched between and in thermal contact with at least two thermoelectric devices. Each of the at least two thermoelectric devices is controlled to collaboratively heat or cool the at least a portion of the heat transfer plate/block sandwiched between and in thermal contact with them.

LON It should be understood that the heat transfer plates can be heat transfer blocks. That is, the heat transfer members need not be planar, but can take any suitable shape. This should be recalled, and understood to apply, wherever reference is made to a heat transfer plate or a heat transfer block in this specification. The heat transfer plates, blocks or, more generally, members of the invention should be made of materials with good thermal conductivity, such as metals or graphite. The skilled person will be able to select from the wide range of suitable materials when designing a particular system according to the invention, and may make use of composite materials or otherwise mix suitable materials.

[012] Thermoelectric devices are typically arranged in thermal contact with and mounted directly onto heat transfer plates/blocks and heat sinks, to provide good thermal conduction. Increasing heat transfer requires more power, more devices it) and/or more powerful devices, for example devices having multiple semiconductor elements in a stacked configuration. In other words, advancing the coefficient of performance for thermoelectric cooling and heating devices requires improvements in the design, materials and arrangements of the thermoelectric modules and assemblies.

[013] In a heating mode, a controlled electrical power supply powers the individual thermoelectric devices to transfer heat into the heat transfer plate/block, raising its temperature, which in turn raises the temperature of the substance or object in thermal contact with the heat transfer plate/block. In a cooling mode, the controlled electrical power supply powers the individual thermoelectric modules to transfer heat away from the heat transfer plate/block, lowering its temperature, so that it in turn absorbs heat from the substance or object in thermal contact with the heat transfer plate/block.

[014] The invention provides thermoelectric devices positioned on different or opposing sides of a heat transfer plate/block, to increase the power used for heat transfer per unit area of heat transfer plate/block, and thereby improve the rate of heat exchange with a substance or object in contact with (e.g. passing through) the heat transfer plate/block. The concentrating effect of the sandwich configuration also increases the maximum heat energy that can be transferred to the heat transfer plate/block.

[15] Where the substance being heated or cooled by contact with the heat transfer plate/block is a fluid, passing through or across the heat transfer plate/block, the path of the substance through or across the heat transfer plate/block can be designed to increase the time the substance spends in contact with the heat transfer plate/block, or increase the surface area of the substance in thermal contact with the heat transfer plate/block. For example, a meandering path can be provided across or through the heat transfer plate/block. The path may be zig-zagged, or otherwise meandered in order to maximise exposure of the substance to the heat transfer plate/block.

[16] Multiple heat transfer plates/blocks may be arranged to concentrate heat transfer, and may be designed to increase or optimise the surface area in contact with the substances or objects in thermal contact with the heat transfer plates/blocks. heat transfer plates/blocks for use with the navention may, for example, be hollow, spiral, finned (internally and/or externally), fluted, twisted, they may incorporate inhibitors or comprise one or more tubes of the substance in thermal contact with the heat transfer plates/blocks. The heat transfer plates/blocks may be round, rectangular, or have other shapes, depending on the particular circumstances of their use. Tubes used in this navention need not have circular cross-section, and the term 'tube' is intended to cover any elongate fluid conduit, of any shape.

[17] Heat transfer plates/blocks of the invention may be incorporated into assemblies such that they are partially or wholly enclosed by or situated within ducts, chambers, reservoirs, pipes. They may, alternatively, be external to an assembly. Thermoelectric modules of the invention may be incorporated into assemblies such that they are partially or wholly enclosed within equipment. They may, alternatively, be external to the equipment.

[18] Heat transfer plates/blocks of the invention may contain a single tube, or multiple tubes, and fluid may move through the tubes in the same direction, or in different directions, or with time-varying direction.

[19] The objects or substances in thermal contact with heat transfer plates/blocks of the invention may include fluids, liquids, gases, solid materials, phase-change materials, or any combination of these.

[20] The thermoelectric modules in thermal contact with the heat transfer plate/block may be sandwiched around a portion of the heat transfer plate/block which is proximate portions of the heat transfer plate/block in thermal contact with the substances or objects to be heated or cooled. Alternatively, the thermoelectric modules in thermal contact with the heat transfer plate/block may be sandwiched around a portion of the heat transfer plate/block which is spatially separated from(but still in thermal communication with) portions of the heat transfer plate/block in thermal contact with the substances or objects to be heated or cooled.

[21] The number, size, design and arrangement of the thermoelectric modules, heat transfer plates/blocks, controllers, power storage devices and so on may vary to suite different applications and requirements.

[22] In embodiments of the invention comprising fluid flow through or across the heat transfer plates/blocks, the fluids may be pressurised or de-pressurised, and may be pumped, or moved by convection, or otherwise caused to flow. Where necessary, filters can be incorporated into the system to improve quality to remove contaminants.

Statement of Invention

[023] The invention provides an assembly as defined in claim 1.

Brief Description of Drawings

[24] The invention will now be described, by way of example only, with reference to the figures.

[25] Figure 1 shows an assembly comprising two thermoelectric modules sandwiched around a heat transfer plate, housed in a casing, with heat sinks and 5 fans provided at the external sides of the thermoelectric modules.

[26] Figure 2 shows an example of a heat transfer plate enclosing a tube having a meandering configuration.

[27] Figure 3 shows an assembly with two heat transfer plates sandwiched between three thermoelectric modules, the external thermoelectric modules having external side heat sinks.

[28] Figure 4 shows an example of a heat transfer array of the invention, in a casing, with arrows indicating the transfer of heat in a first operating mode [29] Figure 5 shows a heat transfer array of the invention with arrows indicating the transfer of heat in a second operating mode.

[030] Figure 6 shows a thermal cuboid assembly, housing four tubes, with four thermoelectric modules in thermal contact with a respective four sides.

[031] Figure 7 shows a thermal cuboid assembly, housing a single tube, with four thermoelectric modules in thermal contact with a respective four sides.

Detailed Description of Drawings

[032] In order to aid understanding of the invention, embodiments of which are depicted in Figures 4 and 5, Figure 1 depicts an assembly with a hollow heat transfer plate 1 sandwiched between thermoelectric modules 2. In a heating mode, the thermoelectric modules 2 are powered to transfer heat from the external side 3 to the heat transfer plate 1, thereby heating the heat transfer plate 1. A fluid 4 passing through the hollow portion 5 of the heat transfer plate 1 is heated by the heated heat transfer plate 1. In a cooling mode, by reversing the polarity of the electrical power supplied to the thermoelectric modules 2, heat is transferred from the heat transfer plate 1 to the external sides 3. Heat is then absorbed by the cooled heat transfer plate 1 from the fluid 4 passing through the hollow portion 5 of the heat transfer plate 1.

19331 The assembly is housed in a casing 6, and the external faces 3 of the thermoelectric modules 2 are thermally coupled to finned heat sink plates 7 with proximate fans 8, for improved heat transfer.

10341 The fluid may 4 flow through a tube 9 or other suitable conduit which passes through the hollow portion 5 of the heat transfer plate 1 and extends beyond it, from the source to the outlet or destination of the fluid 4. The tube 9 is typically made of a flexible, thermally conductive material. Conduits 9 may, alternatively, be fixed to or in thermal communication with a face of the heat transfer plate 1, which may be provided with external fixing means to accommodate suitable conduits. Tn other examples, heat transfer plates 1 may define recesses on one or more of their surfaces to accommodate suitable conduits 9 without wholly encompassing them. In still other examples, the fluid 4 can pass through the hollow portion 5 of the heat transfer plate 1 without a conduit, making direct contact with the surfaces of the hollow portion 5. In order to conduct the fluid from its source to the heat transfer plate 1, and from the heat transfer plate 1 to its outlet or destination, tubes or conduits 9 should be connected to the inlet and outlet of the hollow portion 5, with suitable sealing arrangements.

10351 Each thermoelectric module 2 in this and all of the following instructional examples and embodiments is connected to a power source 10. The power source may be local or distant. A single power source 10 may provide power to more 25 than one thermoelectric modules 2, or each thermoelectric module 2 may have its own dedicated power source 10. The power sources 10 may include mains power, batteries, renewable sources, super-capacitors, and/or other electrical energy storage systems, in isolation or combination. Suitable power conversion circuitry is provided according to the requirements.

[36] Preferably, the thermoelectric modules 2 of this and all following instructional examples and embodiments are connected to at least one battery or other electrical energy storage system in such a way as to supply power to the battery or other electrical energy storage system, with appropriate conversion circuitry. XXThen no power is supplied to a thermoelectric module 2, and a temperature difference exists across its sides, a current is generated through the thermoelectric module 2 by the natural transfer of heat from the hot side to the cold side. This current can be supplied to the battery or other electrical energy storage system, or used for any other purpose.

[37] Each thermoelectric module in this and all following instructional examples and embodiments is also connected to a controller (not shown). The controller may be local or distant. A single controller may be connected to multiple thermoelectric modules 2, or each thermoelectric module 2 may have its own dedicated controller. If the latter is the case, preferably the multiple controllers are in communication with one another so as to communicate and cooperate in effecting, an overall control strategy. This is particularly important because the invention involves the cooperation of at least five thermoelectric modules 2 to simultaneously either heat or cool each of the at least two heat transfer plates 21, 31, 41 (see Figure 4). Returning to the present instructional example, the controller(s) will switch the thermoelectric module(s) 2 between modes of operation, in particular: a first mode in which heat is supplied to the heat transfer plate 1; a second mode in which heat is extracted from the heat transfer plate 1; and a third mode in which no power is supplied to the thermoelectric module 2 and energy is generated by the thermoelectric module 2 in the presence of a heat difference between its two sides.

10381 As a further instructional example of the principles behind the invention, Figure 2 depicts a heat transfer plate 1 with a hollow passage 5 through it, shown in cross-section from both a face-on perspective and an edge-on perspective. The hollow passage 5 is shaped to increase the exposure of a fluid 4 flowing through the passage 5 to the heat transfer plate 1, by increasing the contact time and/or surface area. To this end, the passage 5 has a meandering shape, in particular a zigzagging shape, in the plane of the heat transfer platel. As in the previous example, the fluid is preferably transferred through a tube or suitable conduit 9, which passes through the hollow portion 5 of the heat transfer plate 1.

10391 As can be seen from the edge-on perspective, finned heat sinks 7 are provided on the external sides 3 of the thermoelectric modules 2. These are optional, but preferable, since they improve the efficiency of heat transfer.

10401 As a further instructional example of the principles behind the invention, Figure 3 depicts an assembly comprising two heat transfer plates 1, 11 sandwiched between three thermoelectric modules 2, 12. The external sides 3 of the external thermoelectric modules 2 are provided with finned heat plates 7, which is preferable but not essential. Since, when powered, each thermoelectric module 2, 12 must have one hot side and one cold side, in such an embodiment, one of the heat transfer plates 1, 11 must be heated if the other 11, 1 is being cooled. For example, if the first heat transfer plate 1 is being heated, the second heat transfer plate 11 must be cooled, while if the first heat transfer plate 1 is being cooled, the second heat transfer plate 11 must be heated. Considering the first option, designating the order of the heat transfer plates and the thermoelectric modules from left to right as shown, a voltage is applied with a first polarity across the first and third thermoelectric modules 2, so that the hot side of the first thermoelectric module faces the first heat transfer plate 1, 11, and the cold side of the third thermoelectric module faces the second heat transfer plate 11, 1. Voltage is applied with a second polarity across the second thermoelectric module 12, so that its hot side faces the first heat transfer plate 1 and its cold side faces the second I 0 heat transfer plate 11. In this way, the first heat transfer plate 1 is heated from both sides and the second heat transfer plate 11 is cooled from both sides, providing more efficient and faster heating and cooling.

[0411 An assembly such as the one depicted in Figure 3 could have an operating mode in which only one heat transfer plate 1, 11 is heated or cooled, for example by powering only two adjacent thermoelectric modules 2, 12. '1'his may offer energy generation opportunities at the unpowered thermoelectric module(s) 2, 12. Furthermore, after a period of operation, when power is stopped to one or both sides of the assembly, energy can be generated by the Seebeck method and stored in an electrical energy storage system, such as a battery, as the system returns to thermal equilibrium. The electricity could be used in any other way.

[0421 Figures 4 and 5 depict embodiments of the invention, which extend the principles of the examples given so far into a two-dimensional array of heat transfer plates with hollow compartments. Nine heat transfer plates 21-41, arranged in three rows and three columns, each enclose respective hollow sections 4-24 with (optional but preferable) tubes or conduits through which a fluid to be heated or cooled flows in use. A thermoelectric module 2 is interposed between each pair of adjacent heat transfer plates 21-41. It will be apparent, therefore, that the 'corner' heat transfer plates 21 have two neighbouring heat transfer plates 31 and are therefore in thermal contact with two thermoelectric modules 2, the 'edge' heat transfer plates 31 have three neighbouring heat transfer plates 21, 41 and are therefore in thermal contact with three thermoelectric modules 2, and the 'central' heat transfer plate 41 has four neighbouring heat transfer plates 31 and is therefore in thermal contact with four thermoelectric modules 2. Although it is not shown in the Figures, it may be beneficial to provide thermoelectric modules on the outside edges of the array. These outer thermoelectric modules may be larger than the inner ones, and may each be in thermal communication with more than one heat transfer plate. Alternatively, some may be smaller.

10431 In such an arrangement, if substantially the same power is supplied to each thermoelectric module 2, with appropriately selected polarities that will be discussed below, the heating/cooling effect will be greater for those heat transfer plates 31, 41 with more neighbours. Therefore, by means of a stepped heat transfer, the central heat transfer plate 41 will be heated or cooled to a more extreme temperature than the edge heat transfer plates 31, which will be heated or cooled in turn to a more extreme temperature than the corner heat transfer plates 21. This may be particularly advantageous in systems which require fluids at a variety of different temperatures.

10441 Figure 4 depicts a first mode of operation for this embodiment. The arrows indicate the direction of heat transfer when the thermoelectric modules 2 are powered in this first mode. As will be clear from the figure, the corner heat transfer plates 21 are cooled, the edge heat transfer plates 31 are heated, and the central heat transfer plate 41 is cooled to a greater degree than the corner heat transfer plates 21.

10451 Figure 5 depicts a second mode of operation for this embodiment. The arrows indicate the direction of heat transfer when the thermoelectric modules 2 are powered in this second mode. As will be clear from the figure, the corner heat transfer plates 21 are cooled, the edge heat transfer plates 31 are heated with heat extracted from the corner heat transfer plates, 21 and cooled by heat extracted to the central heat transfer plate 41, so that the central heat transfer plate 41 is effectively heated by heat extracted from all eight of the other heat transfer plates. The result will be cooled corner heat transfer plates 21, warm edge heat transfer plates 31 and a hot central heat transfer plate 41.

10461 It will be clear that other modes of operation will be possible, such as the opposite to either of the two modes described above. It may also be advantageous to have one or more of the heat transfer plates enclose a thermal reservoir, which may be an enclosed chamber rather than a hollow passage (but this is not necessary), which exists to store thermal energy for use in the other heat transfer plates during future operations, or for any other purpose. This may allow for less wasted heat energy and more efficient operation. The substance contained within the thermal reservoir need not be a fluid; it may be a solid, or a phase change material, or a combination of several materials of different kinds. There may not be a hollow at all, but simply a solid heat transfer plate operating as a thermal reservoir. Alternatively, a thermal reservoir may be provided elsewhere in the system, and may be fully or partially enclosed by the array structure as disclosed, or may be external (but still in thermal communication). The thermal reservoir, where used, need not necessarily be the central element in the array, although this has many advantages, in particular the most direct coupling to all the other elements in the array.

[47] It should also be apparent to the skilled person that, although examples have been provided using a square array with nine elements, the invention applies to an 15 array of any size, with any number of elements, of any suitable shape.

[48] The array can be designed to affect fluids that pass through the system, but it could also be designed to heat/cool solid materials. For example, the array could be arranged to transfer heat to or from a solid core that is fully or partially enclosed within the array, or an external heat transfer plate or heat sink in thermal contact with some or all of the array.

[49] If some elements of the array are not needed at a particular time, their thermoelectric modules can be switched off, and enter a power generating mode to generate electrical energy by the Seebeck effect, as thermal equilibrium is approached across the unpowered thermoelectric modules. This electrical energy can be used or stored according to requirements. This reduces energy wasted in the system when it is not being used at full capacity.

[50] Although much of the foregoing has been focused on active heating and cooling of objects and/or substances by applying a voltage across some or all of the thermoelectric modules in an assembly of the invention, some embodiments could be primarily focused on the generation of energy from heat.

[51] For example, the array shown in Figures 4 and 5 could be installed in a power station chimney, and heat from the waste gases and particles expelled from said chimney would, when passing through the passageways provided by the hollows in the heat transfer plates, heat the heat transfer plates and cause an electrical current to be generated in the thermoelectric modules due to a heat difference across their respective sides. This could be stored in a battery or other electrical energy storage system, or put to whatever other use is required in the context. It may be particularly advantageous to allow the passage of hot particles and gasses through only some of the heat transfer plates of the array, providing a higher heat difference across some of the thermoelectric modules, allowing for more efficient electricity generation.

[52] Another potential use for the invention is in solar energy generation. A 15 conventional solar water heater could be placed in thermal communication with some or all of the heat plates of an array of the present embodiment, and electrical energy can be generated by the heat difference provided by the heated water.

[53] It will be clear to the skilled reader that the array embodiment of Figures 4 and 5 is not the only embodiment of the invention that can be useful primarily for energy generation. Any embodiment of the invention can be used to reclaim electrical energy from heat, by creating a heat difference across the sides of at least one of the thermoelectric modules in the assembly.

[54] In some circumstances, an assembly according to the invention will be used only for energy generation and never for heating or cooling. I Imbodiments for such uses will not need circuitry to apply power to the thermoelectric modules, or control said power supply, but will only need circuitry to receive power from the thermoelectric modules, and store it or use it.

10551 Even outside the context of the array, heat transfer plates can be sandwiched between more than two thermoelectric modules. Figures 6 and 7 show examples of this to further illustrate the principles behind the invention. Figure 6 shows a heat transfer plate or block 1 with rectangular cross section, having a thermoelectric module 2 on each of its four sides. It will be clear that even more efficient heating or cooling can be performed if all of the thermoelectric modules 2 are powered so that their respective hot sides (or cold sides in a cooling mode) are in contact with the heat transfer plate 2. Power can also be generated by the Seebeck effect when some or all of the thermoelectric modules 2 are not powered and the system approaches thermal equilibrium across the unpowered thermoelectric modules.

10561 As shown in Figure 7, in this 'block' embodiment with more than two thermoelectric modules 2 surrounding a heat transfer plate 1, a suitable housing 6 can be provided with heat sinks 7 on the external sides of the thermoelectric modules 2. Fans (not shown) and other means for increasing the efficiency of heat transfer can also be provided. With any instructional example of embodiment of this invention, where a housing 6 is provided, suitable vents or other outlets 50 can be provided proximate exposed thermoelectric modules 2 or heat sinks 7 or fans. These may be grated, or louvred, for example.

10571 Although the heat transfer plates 1 of this example have been shown with square or rectangular cross section, other suitable shapes can be used, and the number of thermoelectric modules 2 adjusted accordingly. More than one hollow passage 5 can be provided through the heat transfer plate 1, if required, or the hollow passage 5 can take a meandering path through the heat transfer plate 1 to maximise the time and/or surface area of the passing fluid in contact with the heat transfer plate 1.

[58] In some embodiments of the invention, the heat transfer plates will not transfer heat to or from other objects or substances. For example, the heat transfer plate may itself be a piece of equipment to be heated or cooled.

[59] In all embodiments of the invention, stopping power to the thermoelectric modules will cause any residual heat in the assembly to transfer from the hotter areas to the cooler areas in order to return to thermal equilibrium. '1'his will generate a current in the thermoelectric modules by the Seebeck effect. This current can be returned to the power supply system or another power supply system, or can be stored in an electrical energy storage system, such as a battery or a super-capacitor for later use.

[60] Since all embodiments of the invention include a plurality of thermoelectric modules, modes of operation could be arranged in which only one or at least not all thermoelectric modules are powered, and the others are used to generate electrical energy. This might be advantageous if the full heating/cooling capacity of the device is not required, as a way of increasing energy efficiency.

[61] When heating/cooling is no longer required and all thermoelectric modules are deactivated, energy efficiency can be increased by generating a current in some or all of the thermoelectric modules by the Seebeck effect and storing it, as the system returns to thermal equilibrium.

[062] Controlling thermoelectric modules individually or in subsets allows for a greater range of operational modes and increased flexibility. For example, a performance profile could be implemented that maximizes both heat transfer by the Peltier effect and enerp.7 recovery through the Seebeck effect.

[063] Although the embodiments described above have generally shown a single conduit or path through a given heat transfer plate or block, or have shown a plurality of conduits or paths, but all having substantially the same orientation, this is not necessary for the invention. fluid conduits or other paths may enter a heat transfer plate or block and exit it at the same side, or at sides which do not oppose one another. A plurality of conduits or paths may pass through a single heat transfer member. Conduits or paths may split or converge in or proximate the heat transfer members, so as to have more or fewer outlets than inlets.

10641 The configuration of the thermoelectric modules has not been discussed in detail in this specification because the skilled person will be very familiar with their configuration and use. Although they have been shown as individual modules, this is purely for illustrative purpose and to avoid obscuring the more important technical details of the invention. It will be understood by the skilled person that the thermoelectric modules used in the various embodiments of the invention can be stacked or arranged in parallel. They can have any suitable shape, and their heat plates can have any suitable shape. They can be held within recesses in the surfaces of the heat transfer members. They may have larger or smaller surface areas than the heat transfer member surfaces with which they are in thermal communication. The skilled person should select suitable design parameters according to the requirements of a particular system.

10651 It will be understood that thermal communication is not required throughout the systems described above, but only between adjacent thermoelectric modules via their intervening heat transfer members, and between the heat transfer members and the objects or substances to which or from which they are transferring heat. Elsewhere, use can be made of thermally insulating materials so as to direct the heat energy to where it is useful, and increase the efficiency of the system.

10661 The invention enhances the performance and efficiency of thermoelectric modules, presenting wider applications and opportunities for energy generation.

[067] Although the invention has been described with reference to several embodiments, these embodiments are not limiting. The scope of the invention is limited only by the claims.

Claims (17)

1. Claims 1. An assembly comprising: a first heat transfer block having first, second, third, and fourth faces; a second heat transfer block or plate, having first and second faces; first, second, third, fourth, and fifth thermoelectric modules, each having respective first and second sides; and power circuitry, wherein: the second side of the first thermoelectric module is thermally coupled to at least a portion of the first face of the first heat transfer block; the first side of the second thermoelectric module is thermally coupled to at least a portion of the second face of the first heat transfer block; the second side of the second thermoelectric module is thermally coupled to at least a portion of the first face of the second heat transfer block; the first side of the third thermoelectric module is thermally coupled to at least a portion of the second face of the second heat transfer block; the second side of the fourth thermoelectric module is thermally coupled to at least a portion of the third face of the first heat transfer block; the first side of the fifth thermoelectric module is thermally coupled to at least a portion of the fourth face of the first heat transfer block; and the power circuitry is connected to the first, second, third, fourth and fifth thermoelectric modules.
2. 2. An assembly according to claim I further comprising: a third heat transfer block having first, second, third, and fourth faces; and sixth, seventh and eighth thermoelectric modules, each having respective first and second sides; wherein: the second side of the sixth thermoelectric module is thermally coupled to at least a portion of the first face of the third heat transfer block; the first side of the seventh thermoelectric module is thermally coupled to at least a portion of the second face of the third heat transfer block; the second side of the fifth thermoelectric module is thermally coupled to at least a portion of the third face of the third heat transfer block; the first side of the eighth thermoelectric module is thermally coupled to at least a portion of the fourth face of the third heat transfer block; and the power circuitry is connected to the sixth, seventh and eighth thermoelectric modules.
3. 3. An assembly according to claim 2, wherein the second heat transfer block or plate is a second heat transfer block, further comprising: a fourth heat transfer block having first, second, third and fourth faces; and ninth, tenth, eleventh and twelfth thermoelectric modules, each with respective first and second sides; wherein: the second heat transfer block further comprises a third and fourth face; the second side of the seventh thermoelectric module is thermally coupled to at least a portion of the first face of the fourth heat transfer block; the second side of the ninth thermoelectric module is thermally coupled to at least a portion of the third face of the second heat transfer block; the first side of the tenth thermoelectric module is thermally coupled to at least a portion of the fourth face of the second heat transfer block; the second side of the tenth thermoelectric module is thermally coupled to at least a portion of the third face of the fourth heat transfer block; the first side of the eleventh thermoelectric module is thermally coupled to at least a portion of the second face of the fourth heat transfer block; the first side of the twelfth thermoelectric module is thermally coupled to at least a portion of the fourth face of the fourth heat transfer block; and the power circuitry is connected to the ninth, tenth, eleventh and twelfth thermoelectric modules.
4. 4. An assembly according to any preceding claim, wherein the power circuitry comprises an electrical energy storage system adapted to receive and store electrical 20 energy generated by any of the thermoelectric modules.
5. 5. An assembly according to claim 4 wherein the electrical energy storage system comprises at least on of: a battery; a super-capacitor.
6. 6. An assembly according to any preceding claim wherein the power circuitry comprises power supply and control circuitry, which is connected to each of the 25 thermoelectric modules so as to controllably supply electrical power to each thermoelectric module.
7. 7. An assembly according to claim 6 wherein the control circuitry is adapted to control the power supply circuitry in a first operational mode, in which the second side of the first thermoelectric module is the hot side, and the first side of the second thermoelectric module is the hot side.
8. 8. An assembly according to claim 6 or claim 7 wherein the control try is adapted to control the power supply circuitry in a second operational mode, in which the second side of the first thermoelectric module is the cold side, and the first side of the second thermoelectric module is the cold side.
9. 9. An assembly according to claim 6 wherein the control circuitry is adapted to control the power supply circuitry in a first operational mode, in which the second side of the first thermoelectric module is the hot side, the first side of the second thermoelectric module is the hot side, the second side of the second thermoelectric module is the cold side, and the first side of the third thermoelectric module is the cold side.
10. 10. An assembly according to claim 6 or claim 9, wherein the control circuitry is adapted to control the power supply circuitry in a second operational mode, in which the second side of the first thermoelectric module is the cold side, the first side of the second thermoelectric module is the cold side, the second side of the second thermoelectric module is the hot side, and the first side of the third thermoelectric module is the hot side.
11. 11. An assembly according to any preceding claim, wherein at least one of the heat transfer blocks or plates is thermally coupled to an object or substance to be heated or cooled by the assembly in use.
12. 12 An assembly according to any preceding claim, wherein at least one of the heat transfer blocks or plates comprises a hollow passage to allow the passage of fluids to be heated or cooled by the assembly in use.
13. 13. An assembly according to claim 12, wherein the hollow passage follows a meandering route through the at least one of the heat transfer blocks or plates.
14. 14. An assembly according to any preceding claim, wherein any side of any thermoelectric module not thermally coupled to a heat transfer block or plate is 5 thermally coupled to a heat sink plate.
15. 15. An assembly according to any preceding claim wherein at least one fan is provided proximate at least some of the heat sink plates.
16. 16. An assembly according to any preceding claim contained in a housing.
17. 17. An assembly according to claim 16 when dependent on any one of claims 14 10 or 15, wherein the housing comprises vents or outlets proximate all heat sink plates.