Thermoelectric power generation device based on gradient porous heat collector

Abstract

According to the temperature difference power generation device based on the gradient porous heat collectors, the smoke cavity is defined by the two oppositely-arranged porous heat collectors, the built-in smoke channels extending in parallel are arranged in the wall thickness of the smoke cavity, a traditional dense rib column structure is abandoned, and a light gradient porous heat collection assembly is formed; flue gas flow distribution is regulated and controlled through gradient change of the distribution density of the inlet holes in the height direction, meanwhile, the built-in parallel flue gas channels guarantee the heat exchange area and uniform heat flow, meanwhile, the use amount of solid materials is greatly reduced, extremely simplification and light weight of the structure are achieved, the power density and the energy density are improved, and the heat exchange efficiency is improved. And secondly, due to the synergistic effect of the gradient inlet hole and the built-in flue gas channel, the flue gas flowing and heat exchange process is optimized, a more uniform temperature field can be formed on the outer wall face of the heat collector, and therefore the working efficiency and reliability of thermoelectric power generation are improved.

Description

Technical Field

[0001] This invention relates to the field of thermoelectric power generation technology, and specifically to a thermoelectric power generation device based on a gradient porous collector. Background Technology

[0002] Thermoelectric power generation technology, based on the Seebeck effect, can directly convert heat energy into electrical energy. Due to its simple structure and reliable operation, it has great application potential in scenarios such as field operations and industrial waste heat recovery. Among them, combustion-driven thermoelectric power generation devices generate high-temperature flue gas through fuel combustion, which flows through the collector and transfers heat to the hot end of the thermoelectric module in contact with its outer wall. Then, a cooling system maintains the low temperature of the cold end, thereby establishing the temperature difference required for power generation.

[0003] To improve heat collection efficiency and temperature uniformity, existing technologies generally employ a structure with hundreds or even thousands of ribs densely and interwoven inside the collector's flow channels. This type of ribbed collector enhances heat exchange by significantly increasing the heat exchange area. However, this reliance on complex internal ribs inevitably leads to a significant increase in the overall weight and volume of the collector, resulting in a bulky structure. Furthermore, the rib structure creates considerable resistance to flue gas flow, limiting the actual heat collection efficiency and the temperature difference improvement achievable by the thermoelectric power generation module. This restricts the overall output power of the device, resulting in generally low power density and energy density.

[0004] In view of this, the inventors have specifically designed a thermoelectric power generation device based on a gradient porous collector, which leads to this invention. Summary of the Invention

[0005] To solve the above problems, the technical solution of the present invention is as follows: A thermoelectric power generation device based on a gradient porous collector includes: Combustion components, including swirl burners, are used to generate high-temperature swirl flue gas; A heat collection assembly is disposed above a combustion assembly and its interface end is connected to the outlet end of the combustion assembly. The porous heat collection assembly includes two coaxially opposite porous heat collectors, and a flue gas chamber for containing flue gas is formed between the two porous heat collectors. Each porous heat collector has several parallel built-in flue gas channels within its wall thickness. Each built-in flue gas channel extends along the height direction of the porous heat collector. Multiple rows of inlet holes are opened on the inner sidewalls of the two porous heat collectors, which are respectively connected to the built-in flue gas channels one by one. The distribution density of each row of inlet holes varies in a gradient along the vertical direction. The chimney assembly has its bottom connected to the exhaust port of the built-in flue gas channel for the final discharge of flue gas.

[0006] Preferably, the inlet hole is a circular hole, and the center-to-center distance between adjacent inlet holes in each column increases from bottom to top along the height direction.

[0007] Preferably, the center-to-center distance between adjacent entrance holes in each column increases in an arithmetic progression of 0.4m to 0.6m from bottom to top.

[0008] Preferably, the center-to-center distance between the first and second inlet holes in each column is 3mm to 5mm.

[0009] Preferably, it also includes two thermoelectric generators, water-cooled heat sinks, fixing plates, and fixing rods. The two thermoelectric generators are respectively disposed on the outer walls of the two porous collectors and their hot ends are thermally connected to the outer walls of the porous collectors. The two water-cooled heat sinks are respectively connected to the cold ends of the two thermoelectric generators. The two fixing plates are respectively disposed on the outer sides of the two water-cooled heat sinks, and the fixing rod passes through the two fixing plates to achieve fastening.

[0010] Preferably, the combustion assembly further includes a combustion chamber, the outlet of the swirl burner is connected to the inlet of the combustion chamber, and the outlet of the combustion chamber is connected to the flue gas chamber.

[0011] Preferably, the swirl angle of the swirl burner is 40° to 50°, and the swirl length of the swirl burner is 6mm to 10mm.

[0012] Preferably, the combustion chamber sidewall is provided with an observation window.

[0013] The technical solution provided by this invention has the following beneficial effects: This invention uses two opposing porous collectors to form a flue gas chamber, with parallel-extending built-in flue gas channels within its wall thickness. Multiple rows of inlet holes are formed on the inner walls of the two porous collectors, creating a lightweight gradient porous heat collection component. The flue gas flow distribution is regulated by the gradient variation in the distribution density of the inlet holes along the height direction. Simultaneously, the built-in parallel flue gas channels significantly reduce the amount of solid materials used while ensuring heat exchange area and uniform heat flow, achieving extreme simplification and lightweighting of the structure. This improves power density and energy density, perfectly suited for portable applications. Furthermore, the synergistic effect of the gradient inlet holes and the built-in flue gas channels optimizes the flue gas flow and heat exchange process, helping to form a more uniform temperature field on the outer wall of the collectors, thereby improving the efficiency and reliability of thermoelectric power generation. Attached Figure Description

[0014] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0015] in: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the porous solar collector in this invention; Figure 3 This is a schematic cross-sectional view of the porous solar collector in this invention; Figure 4 It is a temperature distribution diagram of the entrance hole, which is denser at the top and sparser at the bottom; Figure 5 It is a temperature distribution diagram showing the uniform distribution of the inlet holes; Figure 6 It is a temperature distribution diagram of the entrance hole, which is sparse at the top and dense at the bottom.

[0016] Label Explanation: In the diagram: 1. Perforated solar collector; 2. Built-in flue gas passage; 3. Inlet hole; 4. Thermoelectric generator; 5. Water-cooled heat sink; 6. Fixing clamp; 7. Fixing rod; 8. Swirl burner; 9. Combustion chamber; 91. Observation window. Detailed Implementation

[0017] To make the technical problems, solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0018] Please see Figures 1-6 This is a preferred embodiment of the present invention, a gradient porous collector-based thermoelectric power generation device, comprising: The combustion assembly generates high-temperature swirling flue gas through the swirling burner 8; A heat collection assembly, positioned above the combustion assembly and with its interface end connected to the outlet end of the combustion assembly, comprises two coaxially opposed porous heat collectors 1. A closed or semi-closed flue gas chamber for containing flue gas is formed between the two porous heat collectors 1. Within the wall thickness of each porous heat collector 1, several internal flue gas channels 2 extending parallel to the height direction of the heat collector are machined. Each internal flue gas channel 2 extends along the height direction of the porous heat collector 1. Multiple rows of inlet holes 3 are formed on the inner sidewalls of the two porous heat collectors 1, each communicating with one of the internal flue gas channels 2. The distribution density of each row of inlet holes 3 varies gradually from top to bottom. Each row of inlet holes 3 uniquely and precisely communicates with the inlet end of one internal flue gas channel 2, avoiding flow field chaos. The distribution density of each row of inlet holes 3 gradually decreases from bottom to top along the height direction. In the high-temperature region (lower part) near the burner, the perforations are denser, allowing more high-temperature flue gas to quickly enter the internal channels, enhancing the intense heat exchange in the initial stage. In the upper region, further away from the heat source, the perforations gradually become sparser, controlling the flue gas flow and preventing over-cooling due to excessive flow, thus achieving a "compensatory" heat distribution along the height. Its working principle is based on thermal convection and radiation heat transfer: a smaller initial spacing (denser portion) increases the heat exchange area and improves initial heat absorption efficiency; while a gradually increasing spacing (sparser portion) helps guide the hot gas flow upwards, reducing flow resistance, thereby achieving a more efficient and uniform heat exchange overall.

[0019] High-temperature swirling flue gas enters the flue gas chamber formed by two porous collectors 1 from the burner. The flue gas fills the chamber and has a certain pressure. Subsequently, driven by pressure, the flue gas is actively distributed into various built-in flue gas channels 2 through the gradient-distributed inlet holes 3 on the inner wall. Due to the "dense at the bottom and sparse at the top" arrangement of the holes, the lower channel receives more high-temperature flue gas flow, while the upper channel receives relatively less flow. The flue gas flows upward in its independent parallel built-in channels, during which the heat it carries is efficiently conducted to the outer wall of the collector through the collector wall (i.e., the channel wall), thereby establishing a stable temperature difference and generating electricity. Finally, the cooled flue gas flows out from the outlet of each built-in channel and is discharged into the chimney. By eliminating the bulky internal rib column group and adopting a design that integrates flow channels within the wall thickness, the amount of metal material used is greatly reduced, resulting in a significant reduction in the weight and volume of the collector and even the entire device. The actual measured device weighs as little as about 1.3 kg and has a volume comparable to an A4 sheet of paper; the gradient distribution of the inlet holes 3 corrects the temperature decay that naturally occurs during the flow of flue gas, making the heat distribution more uniform in the height direction of the collector.

[0020] The bottom of the chimney assembly is connected to the flue gas outlet of the built-in flue gas channel 2 for the final discharge of flue gas. Its bottom is also connected to the confluence of the outlets of all built-in flue gas channels 2 for the final discharge of the low-temperature flue gas that has completed heat exchange into the atmosphere, forming a smooth flue gas flow path.

[0021] Please see Figures 1-3 The inlet holes 3 are circular. The center-to-center distance between adjacent inlet holes 3 in each row increases arithmetically in increments of 0.5 m from bottom to top. The center-to-center distance between the first and second inlet holes 3 in each row is 4 mm, and the diameter of each inlet hole 3 is 2 mm, with a porosity of 24.37%. This pore distribution from dense to sparse helps optimize the heat transfer path and efficiency, and directly reduces material usage, achieving lightweight design. Due to the gradient characteristics of the pore distribution, the flue gas diversion is most active in the lower region where the temperature is highest (dense pores); as the flue gas flows upward and the temperature gradually decreases, the diversion effect weakens accordingly (sparse pores). This "intelligent distribution" mechanism enables dynamic heat balance across the entire height of the collector.

[0022] Please see Figures 1-3 Two TEM thermoelectric generators 4 are thermally connected to the outer walls of two porous solar collectors 1, respectively. Their hot ends directly receive heat from the solar collectors, achieving efficient conversion of thermal energy into electrical energy. Two water-cooled heat sinks 5 are tightly attached to the cold ends of the thermoelectric generators 4, rapidly dissipating heat through forced water cooling and other methods, thereby establishing and maintaining a stable high temperature difference on both sides of the generator, which is the physical basis of the Seebeck effect for efficient power generation. Two fixing plates 6 are respectively set on the outside of the water-cooled heat sinks 5 and are secured together by fixing rods 7 passing through them. This symmetrical clamping structure, through uniformly applied pre-tightening force, presses the solar collectors, thermoelectric generators 4, and water-cooled heat sinks 5 into a rigid, low-thermal-resistance integrated module. This maximizes the reduction of contact thermal resistance between the interfaces of each layer, ensuring a smooth and efficient heat transfer path from the heat source to the cold end, directly improving the thermoelectric conversion efficiency; and enhancing the mechanical stability and shock resistance of the entire power generation module, making it suitable for outdoor movement or bumpy environments.

[0023] Please see Figure 1 The combustion assembly includes a swirl burner 8 and a combustion chamber 9. The outlet of the swirl burner 8 is connected to the inlet of the combustion chamber 9, and the outlet of the combustion chamber 9 is connected to the flue gas chamber. The swirl angle of the swirl burner 8 is 45°, and the swirl length of the swirl burner 8 is 8 mm. An observation window 91 is provided on the side wall of the combustion chamber 9. This swirl burner 8 can promote the full mixing of fuel and air, achieving more complete combustion and effectively reducing pollutants generated by incomplete combustion, making it more environmentally friendly. At the same time, the swirl structure can significantly improve flame stability, giving it stronger wind resistance, making it particularly suitable for outdoor applications. More importantly, the flue gas generated by the swirl burner 8 forms a vortex-shaped upward airflow. This flow field characteristic can guide the high-temperature flue gas to flow more concentratedly to the porous channels on both sides of the collector, thereby working in conjunction with the porous collector to further optimize the heat collection capacity and overall system efficiency.

[0024] Please refer to 4~ Figure 6 This embodiment involves experimental research and simulation. Figures 4-6 The simulations show the Fluent results for three different distributions of circular holes: uniform distribution, denser distribution at the top and sparser distribution at the bottom, and the denser distribution at the bottom and sparser distribution at the top in this design. The inlet temperature is 500 K, the velocity is 1.2 m / s, and the natural heat convection coefficient at the wall is 10 W / m². 2 The temperature is 298.5K. As can be seen from the figure, while the uniform distribution of the circular holes and the denser distribution at the top and sparser distribution at the bottom reduce the maximum temperature difference, they also significantly weaken the heat collection capacity, potentially leading to low power generation efficiency. The circular hole distribution used in this design solves the problem of uneven temperature distribution while enhancing heat collection capacity, resulting in higher output power and efficiency for this thermoelectric generator.

[0025] To achieve a comparative effect, we used a conventional finned collector paired with a swirl burner 8, the collector of this design paired with a swirl burner 8 (both with swirl blade angles of 45° and swirl lengths of 8mm), and the collector of this design paired with a conventional burner (simulating a swirl blade angle of 0°). This was to demonstrate the advantages of the thermoelectric generator driven by the swirl burner 8. The operating conditions were: methane fuel, input power of 1600W (i.e., 2.99 slpm), equivalence ratio of 0.9, ambient temperature of 25℃~26℃, humidity of 50%~60%, and a closed-loop water cooling system to save water resources. The water cooling rate was 2.1L / min. Four fans were used for enhanced heat dissipation. The output load was 30Ω. (Data shown in Tables 1 and 2)

[0026] Table 1 Table 3 The data above shows that the thermoelectric generator based on the solar collector in this invention maintains higher output power and a smaller temperature difference under both the swirl burner 8 and the ordinary burner. Its maximum temperature difference of 16.85℃ and 10.2℃ are both higher than those of the finned thermoelectric generator (maximum temperature difference 32.45℃). Therefore, the thermoelectric generator of this invention achieves a more efficient output power. Furthermore, due to the very small weight and volume of this thermoelectric generator, its energy density and power density are also excellent, at 36Wh / kg and 94395W / m³, respectively. 3 However, due to the structural limitations of finned thermoelectric generators, their energy density and power density are only 10Wh / kg and 55780W / m³, respectively. 3This fully demonstrates the superiority of the thermoelectric power generation device driven by the swirl burner 8 based on the novel porous collector 1. Furthermore, using the same swirl burner 8 and methane as fuel, under the condition of an input power equivalence ratio of 0.9 to 1600W, the temperature uniformity coefficient (average maximum temperature difference / vertical length of the generator plate installation position) of this invention is 0.223. In contrast, the temperature uniformity coefficient of the finned collector is 0.271. This further proves that its temperature uniformity is superior to that of the finned collector.

[0027] In summary, this invention uses two opposing porous collectors 1 to form a flue gas chamber, with parallel-extending built-in flue gas channels 2 within their wall thickness. Multiple rows of inlet holes 3 are formed on the inner walls of the two porous collectors 1, abandoning the traditional dense rib structure and forming a lightweight gradient porous heat collection component. The flue gas flow distribution is regulated by the gradient change in the distribution density of the inlet holes 3 along the height direction. Simultaneously, the built-in parallel flue gas channels significantly reduce the amount of solid materials used while ensuring heat exchange area and uniform heat flow, achieving extreme simplification and lightweighting of the structure, improving power density and energy density, and perfectly suited for portable applications. Furthermore, the synergistic effect of the gradient inlet holes 3 and the built-in flue gas channels 2 optimizes the flue gas flow and heat exchange process, helping to form a more uniform temperature field on the outer wall of the collector, thereby improving the efficiency and reliability of thermoelectric power generation.

[0028] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A thermoelectric power generation device based on a gradient porous collector, characterized in that, include: Combustion components, including swirl burners, are used to generate high-temperature swirl flue gas; A heat collection assembly is disposed above a combustion assembly and its interface end is connected to the outlet end of the combustion assembly. The porous heat collection assembly includes two coaxially opposite porous heat collectors, and a flue gas chamber for containing flue gas is formed between the two porous heat collectors. Each porous heat collector has several parallel built-in flue gas channels within its wall thickness. Each built-in flue gas channel extends along the height direction of the porous heat collector. Multiple rows of inlet holes are opened on the inner sidewalls of the two porous heat collectors, which are respectively connected to the built-in flue gas channels one by one. The distribution density of each row of inlet holes varies in a gradient along the vertical direction. The chimney assembly has its bottom connected to the exhaust port of the built-in flue gas channel for the final discharge of flue gas.

2. The thermoelectric power generation device based on a gradient porous collector according to claim 1, characterized in that, The entrance hole is a circular hole, and the center-to-center distance between adjacent entrance holes in each column increases from bottom to top along the height direction.

3. The thermoelectric power generation device based on a gradient porous collector according to claim 1, characterized in that, The center-to-center distance between adjacent entrance holes in each column increases from bottom to top in an arithmetic progression of 0.4m to 0.6m.

4. A gradient porous collector-based thermoelectric power generation device according to claim 3, characterized in that, The center-to-center distance between the first and second entrance holes in each column, from bottom to top, is 3mm to 5mm.

5. A gradient porous collector-based thermoelectric power generation device according to claim 1, characterized in that, It also includes two thermoelectric generators, water-cooled heat sinks, fixing plates, and fixing rods. The two thermoelectric generators are respectively located on the outer walls of the two porous collectors and their hot ends are thermally connected to the outer walls of the porous collectors. The two water-cooled heat sinks are respectively connected to the cold ends of the two thermoelectric generators. The two fixing plates are respectively located on the outer sides of the two water-cooled heat sinks. The fixing rod passes through the two fixing plates to achieve fastening.

6. A gradient porous collector-based thermoelectric power generation device according to claim 1, characterized in that, The combustion assembly further includes a combustion chamber, the outlet of the swirl burner is connected to the inlet of the combustion chamber, and the outlet of the combustion chamber is connected to the flue gas chamber.

7. A gradient porous collector-based thermoelectric power generation device according to claim 6, characterized in that, The swirl angle of the swirl burner is 40° to 50°, and the swirl length of the swirl burner is 6mm to 10mm.

8. A gradient porous collector-based thermoelectric power generation device according to claim 1, characterized in that, The combustion chamber sidewall is provided with an observation window.

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