Device and method for reducing exhaust heat load of natural gas heavy truck through thermoelectric power generation system

Abstract

The invention discloses a device and a method for reducing exhaust heat load of a natural gas heavy truck by using a thermoelectric power generation system, and belongs to the technical field of automobile exhaust heat energy recovery and thermoelectric power generation. Through the Seebeck effect, the temperature difference between high-temperature exhaust gas and the environment cold end is directly converted into electric energy, the heat load of the natural gas heavy truck is reduced, heat in the exhaust gas can be recycled, and the energy utilization rate is increased. Geometric parameter length and width are dynamically optimized through longitudinal and transverse subunit division and a self-adaptive iterative algorithm, the exhaust outlet temperature is accurately controlled to reach a target interval, and installation space limitation and thermal management requirements are considered. Based on a temperature prediction model of a differential equation set, system parameters are dynamically optimized, and cooperative improvement of exhaust heat load reduction and power generation efficiency is ensured. The technology effectively prolongs the service life of an exhaust system, reduces fuel consumption, and assists the natural gas heavy truck to achieve the dual purposes of energy conservation, consumption reduction and low-carbon operation.

Description

Technical Field

[0001] This invention belongs to the field of automotive exhaust heat recovery and thermoelectric power generation technology, specifically relating to a device and method for coordinated control of exhaust heat load of natural gas heavy trucks based on a thermoelectric power generation system. Background Technology

[0002] With the global energy structure transformation and increasingly stringent environmental policies, natural gas heavy-duty trucks have become an important choice in the road transportation sector due to their lower carbon emissions. However, the exhaust temperature of natural gas engines is generally higher than that of traditional diesel engines, with exhaust heat loads reaching as high as 600°C. o C not only wastes a lot of heat energy, but also exacerbates the risk of high-temperature aging of exhaust system components. Currently, thermal management for such high-temperature exhaust gases mainly relies on radiator forced cooling or waste heat boiler recovery. However, the former is energy-intensive and cannot achieve energy reuse, while the latter is difficult to adapt to the vehicle environment due to its large size.

[0003] Thanks to advancements in modern technology, the performance of thermoelectric materials has significantly improved, leading to the widespread application of thermoelectric technology in heat recovery, such as in automotive exhaust waste heat recovery and industrial waste heat recovery. Thermoelectric generators demonstrate multiple advantages in waste heat recovery from natural gas heavy-duty trucks. Their core principle utilizes the Seebeck effect to directly convert the temperature difference between the high-temperature exhaust gas in the engine exhaust system and the cold ambient environment into electrical energy, eliminating the need for mechanical transmission devices, resulting in a simple structure and low maintenance costs. Compared to traditional waste heat recovery technologies such as turbocharging or organic Rankine cycles, thermoelectric generators offer greater system compactness and environmental adaptability, allowing for flexible integration into exhaust pipes or catalytic converter surfaces, effectively recovering waste heat energy and reducing fuel consumption. Simultaneously, the electricity recovered by thermoelectric generators can be directly stored in the vehicle's battery or drive auxiliary equipment (such as air conditioning and electronic systems), reducing engine load and extending the range of electrified components. Furthermore, thermoelectric generators operate entirely in a solid state with no moving parts, are resistant to high temperatures and vibration, have a lifespan matching that of the truck engine, and their zero-emission characteristics help automakers meet stringent carbon emission regulations, achieving the dual goals of energy conservation, cost reduction, and low-carbon transformation. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a device and method for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system. This thermoelectric power generation system is installed between the catalytic converter and the muffler, and uses thermoelectric power generation technology as its core to absorb the heat from the high-temperature exhaust gas to effectively reduce the heat load of the natural gas heavy-duty truck. This invention dynamically optimizes its geometric parameters (length and width) through longitudinal and transverse sub-unit division and an adaptive iterative algorithm, precisely controlling the exhaust outlet temperature to the target range, while taking into account both installation space limitations and thermal management requirements.

[0005] The objective of this invention is achieved through the following technical solution: A device for reducing the exhaust heat load of a natural gas heavy-duty truck using a thermoelectric power generation system includes a connector, a heat exchanger, a connecting pipe, a water-cooled plate, fins, and a thermoelectric module. The connector is connected to the front and rear ends of the heat exchanger via the connecting pipe. The lower surface of the thermoelectric module is attached to the heat exchanger, and the upper surface is attached to an S-shaped water-cooled plate. The device includes a heat exchanger, a thermoelectric module, a water-cooled plate, a connector, and a connecting pipe. The heat exchanger is installed between the catalytic converter and the muffler of the natural gas heavy-duty truck to absorb the high-temperature heat from the engine exhaust. The heat exchanger is a modular structure composed of several longitudinally and laterally combinable sub-units. Each sub-unit has aluminum plate fins inside to enhance heat transfer. The total length and width of the heat exchanger can be adjusted between adjacent sub-units. The thermoelectric module is attached to the outer surface of the heat exchanger and is in thermal contact with the water-cooled plate of the S-shaped cooling water channel, forming a thermoelectric power generation unit. The number and arrangement of the sub-units can be adjusted.

[0006] The heat exchanger is an aluminum square structure with a length, width, and height of [missing information]. L 1. W 1 and H 1. Wall thickness is δ The connecting pipes before and after the heat exchanger are of the same type and have the same diameter. D 1. The appropriate size can be selected according to the diameter of the exhaust pipe.

[0007] The length and width of the thermoelectric module are both L 3. Neatly arranged on the upper and lower surfaces of the heat exchanger, with a longitudinal spacing of [missing information]. l The horizontal spacing is d 2; The thermoelectric module consists of a ceramic plate, copper electrodes, a P-type semiconductor and an N-type semiconductor. The upper and lower ends of the P-type semiconductor and the N-type semiconductor are connected in series through the copper electrodes and sandwiched between the upper and lower ceramic plates.

[0008] The heat exchanger is internally fitted with a thickness of t The height is H 3, length is L 3 aluminum plate fins, and at a spacing d 1. Neatly arranged in the exhaust gas passage of the heat exchanger, among which H 3= H 1-2 δ , L 3= L 1-2 l .

[0009] The length of the water-cooled plate is L 2, thickness is H 2, width is W 2. The length of the water-cooled plate is equal to the length of the heat exchanger, i.e. L 2= L1, and its width is half the width of the heat exchanger, that is W 2= W 1 / 2; The water-cooled plate is provided with an S-shaped cooling water channel for introducing cooling water, and the diameter of the S-shaped cooling water channel is [missing information]. D 2.

[0010] A method for reducing the exhaust heat load of natural gas heavy trucks using a thermoelectric power generation system involves establishing a set of differential equations to predict the temperature of the thermoelectric power generation system and setting reasonable boundary conditions to calculate the exhaust temperature at the heat exchanger outlet. For the length of the heat exchanger L 1. Perform iterative calculations; if in the number of iterations... i satisfy i ≤ n / 2 If the requirement is met within a certain time, the iteration process ends; if the number of iterations reaches a certain threshold... i = n / 2 If the conditions are still not met, the width of the heat exchanger is iteratively calculated until the requirements are met, and the length of the heat exchanger is calculated accordingly. L 1= L ± i × l ,in L This is the initial length of the heat exchanger. i The number of iterations to be determined when determining the length of the heat exchanger. l The length of the heat exchanger is the change in length during each iteration of the calculation; the width of the heat exchanger. W 1= W ± y × w in W This is the initial width of the heat exchanger. y The number of iterations to be determined when determining the width of the heat exchanger. w This represents the width change value of the heat exchanger during each iteration of the calculation.

[0011] The heat exchanger is divided into several sub-units along its longitudinal direction based on the number of rows of thermoelectric modules. Each sub-unit includes a row of thermoelectric modules and half of the space between them. The initial structure of the heat exchanger consists of n sub-units, named N1, N2, N3...N n-1 N n During the iterative calculation, the length of the heat exchanger changes according to the length of one sub-unit each time, i.e. l = l / 2 + L 2+l / 2, and the number of iterations is limited to satisfy i ≤ n / 2 .

[0012] The heat exchanger is divided into several sub-units along its transverse direction based on the number of rows of thermoelectric modules. Each sub-unit includes a row of thermoelectric modules and the modules before and after it. d The initial structure of the heat exchanger consists of m sub-units, named K1, K2, K3...K, with a 2 / 2 interval. m-1 K m During the iterative calculation, the width of the heat exchanger changes according to the length of a sub-unit each time, i.e. w = d 2 / 2 + L 2+ d 2 / 2.

[0013] First, consider the length of the heat exchanger. L 1. Perform iterative calculations; if the number of iterations... i satisfy i ≤ n / 2 If the requirement is met within a certain time, the iteration process ends; if the number of iterations reaches a certain threshold... i = n / 2 If the conditions are still not met, the width of the heat exchanger is iteratively calculated until the requirements are met.

[0014] The final length and width of the heat exchanger are determined by selecting the desired exhaust outlet temperature conditions. T 1< T < T 2) Firstly in i Calculate the exhaust outlet temperature of the heat exchanger in its initial state when = 0. T 0, and determine T Does 0 satisfy the temperature range? If not, then according to... T 0 deviation T 1 and T Adjustment for case 2, i.e., when T 0< T 1 hour setting L 1= L - i ×Δ l , W 1= W - y ×Δ w , and when T 0> T 2 hours L 1= L+ i ×Δ l , W 1= W + y ×Δ w Then let i = i +1, return to recalculate exhaust outlet temperature T i Check again whether it meets the requirements. T 1< T i < T 2. The loop continues until the condition is met; if in i achieve n / 2 If the condition is still not met, then the width of the heat exchanger will be iterated, starting from... y Incrementing from 1, and calculating the corresponding temperature. T i+y until satisfied T 1< T i+y < T 2. This determines the final length and width of the heat exchanger.

[0015] The beneficial effects of this invention are as follows: This invention provides a device and method for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system, wherein the length of the heat exchanger in the thermoelectric power generation system is... L ± i ×Δ l Width is W ± y ×Δ w The exhaust temperature at the heat exchanger outlet is obtained by solving a system of differential equations, and a suitable Δ is selected. l and Δ w The values ​​are iteratively solved to ultimately control the exhaust temperature at the heat exchanger outlet within the target range, thus allowing the specific dimensions of the heat exchanger to be determined according to specific requirements. The thermoelectric power generation system of this invention is installed between the catalytic converter and the muffler. Using thermoelectric power generation technology as its core, it absorbs the heat from high-temperature exhaust gas to effectively reduce the heat load of natural gas heavy-duty trucks. Furthermore, the specific dimensions of the thermoelectric power generation system can be intelligently calculated based on the required reduction in heat load. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a device for reducing the exhaust heat load of natural gas heavy trucks using a thermoelectric power generation system according to the present invention. Figure 2 This is the front view of the thermoelectric power generation system; Figure 3 A schematic diagram of the installation of a thermoelectric module in a thermoelectric power generation system; Figure 4 This is a schematic diagram of the internal fin installation of a thermoelectric power generation system. Figure 5 A schematic diagram showing the sub-unit division of the heat exchanger along the longitudinal direction; Figure 6 A schematic diagram showing the sub-unit division of the heat exchanger along the lateral direction; Figure 7 This is a schematic diagram of the S-shaped cooling water channel inside the water-cooled plate; Figure 8 A schematic diagram of the internal structure of a thermoelectric module used in a thermoelectric power generation system; Figure 9 Flowchart for calculating the structural parameters of a thermoelectric power generation system; The attached diagram is labeled as follows: 1-Connector, 2-Heat exchanger, 3-Connecting pipe, 4-Water cooling plate, 5-Plate fin, 6-Thermoelectric module, 7-Ceramic plate, 8-Copper electrode, 9-P-type semiconductor, 10-N-type semiconductor. Detailed Implementation

[0017] To provide a clearer and more complete description of the present invention, the implementation of the present invention will be illustrated with reference to the accompanying drawings and the following embodiments, but the scope of protection of the present invention is not limited thereto.

[0018] like Figure 1 , 2 The diagram shows a device for reducing the exhaust heat load of a natural gas heavy-duty truck using a thermoelectric power generation system, according to the present invention. It includes a connector 1, a heat exchanger 2, a connecting pipe 3, a water-cooled plate 4, fins 5, and a thermoelectric module 6. The connector 1 is connected to the front and rear ends of the heat exchanger 2 via the connecting pipe 3. The lower surface of the thermoelectric module 6 is attached to the heat exchanger 2, and the upper surface is attached to the S-shaped water-cooled plate 4. The heat exchanger 2 is an aluminum square structure with dimensions of length, width, and height of [missing information]. L 1. W 1 and H 1. Wall thickness is δ The connecting pipes 3 connecting the heat exchanger 2 at the front and rear are of the same type and have the same diameter. D 1. The appropriate size can be selected based on the diameter of the exhaust pipe. The heat exchanger 2 has an internal thickness of [missing information]. t The height is H 3, length is L 3 aluminum plate fins, and at a spacing d 1. They are neatly arranged in the exhaust gas channel of heat exchanger 2. The length of water-cooled plate 4 is... L 2, thickness is H 2, width is W 2, wherein the length of the water-cooled plate 4 is equal to the length of the heat exchanger 2, that is... L 2= L1, and its width is half the width of heat exchanger 2, that is W 2= W 1 / 2; The water-cooled plate 4 is provided with an S-shaped cooling water channel for introducing cooling water, and the diameter of the S-shaped cooling water channel is... D 2.

[0019] like Figure 3 The diagram shows the installation schematic of a thermoelectric module for a device of the present invention that uses a thermoelectric power generation system to reduce the exhaust heat load of natural gas heavy trucks. The length and width of the thermoelectric module 6 are both... L 3, neatly arranged on the upper and lower surfaces of the heat exchanger 2, with a longitudinal spacing of [missing information]. l The horizontal spacing is d 2; The thermoelectric module 6 is composed of a ceramic plate 7, a copper electrode 8, a P-type semiconductor 9 and an N-type semiconductor 10. The upper and lower ends of the P-type semiconductor 9 and the N-type semiconductor 10 are connected in series through the copper electrode 8 and sandwiched between the upper and lower ceramic plates 7.

[0020] like Figure 4 The diagram shows the internal fin installation of a device for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system according to the present invention. The heat exchanger 2 contains fins with a thickness of [missing information]. t The height is H 3, length is L 3 aluminum plate fins, and at a spacing d 1 are neatly arranged in the exhaust gas passage of heat exchanger 2, among which H 3= H 1-2 δ , L 3= L 1-2 l .

[0021] like Figure 5 , 6 The diagram shows the longitudinal and transverse sub-unit division of a device for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system according to the present invention. The heat exchanger 2 is divided longitudinally into several sub-units based on the number of rows of thermoelectric modules 6. Each sub-unit includes a row of thermoelectric modules 6 and the units before and after them. l The interval is 2 / 2; the initial structure of heat exchanger 2 consists of n sub-units, named N1, N2, N3...N n-1 N n During the iterative calculation, the length of heat exchanger 2 changes according to the length of one sub-unit each time, that is... l = l / 2+ L 2+ l / 2, and the number of iterations is limited to satisfy i ≤ n / 2 The heat exchanger 2 is divided into several sub-units along the transverse direction based on the number of rows of thermoelectric modules 6. Each sub-unit includes a row of thermoelectric modules 6 and the units before and after them. d The initial structure of heat exchanger 2 consists of m sub-units, named K1, K2, K3, ..., K, with a 2 / 2 interval; m-1 K m During the iterative calculation, the width of heat exchanger 2 changes according to the length of one sub-unit each time, i.e. w = d 2 / 2+ L 2+ d 2 / 2.

[0022] like Figure 9 As shown, the present invention also provides a method for determining the parameters of a device for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system, comprising the following steps: Step (1): Determine the dimensions of each component of the thermoelectric generator and assemble them together, such as... Figure 1 As shown in Table 1, the thermoelectric generator mainly consists of a heat exchanger 2, a water-cooled plate 4, plate fins 5, and a thermoelectric module 6. The dimensions of each component are shown in Table 1. Table 1. Dimensions of Components in a Thermoelectric Power Generation System

[0023] The overall structure of the thermoelectric module 6 selected in this example is as follows: Figure 8 As shown, its detailed dimensions are shown in Table 2: Table 2. Dimensions of each component of the thermoelectric module

[0024] Step (2), calculate l , w And determine the maximum number of iterations for the length and width. In this example, the longitudinal spacing of the thermoelectric modules is 5 mm, and the transverse spacing is 2 mm, that is... l = 5 mm, d 2 = 2 mm. Therefore, the length of each longitudinal subunit of the heat exchanger is... l / 2+ L 2+ l / 2 = 45 mm, that is l = 45mm; The length of each transverse subunit of the heat exchanger is d 2 / 2+ L 2+ d 2 / 2 = 42 mm, that is w = 42mm. Based on the initial length of the heat exchanger, it can be divided into 11 sub-units along the longitudinal direction, i.e., n = 11. i ≤ 5; Based on the initial width of the heat exchanger, the heat exchanger can be divided into 6 sub-units along the transverse direction, i.e., m = 6.

[0025] Step (3) Establish the set of differential equations followed by the thermoelectric power generation system, which mainly involves the fluid domain and the heat transfer domain.

[0026] (i) Computational fluid dynamics equations are used to accurately represent the fluid flow behavior in the fluid domain:

[0027]

[0028]

[0029] in, p It is fluid pressure. It is a vector of fluid velocity. T This indicates absolute temperature. ρ , μ , λ and c These represent inherent fluid properties, specifically density, molecular viscosity, thermal conductivity, and specific heat.

[0030] (ii) The exhaust gas and cooling water flow of a thermoelectric power generation system can be considered turbulent. In this study, standard... k-ε Turbulence models are used to calculate turbulence, including the following transport equations:

[0031]

[0032]

[0033] in, P k It is the amount of shear energy generated by turbulent kinetic energy. k Represents turbulent kinetic energy. ε This represents the rate of energy dissipation in turbulence. C 1ε , C 2ε , C μ , σ k and σ ε These are fixed constants, expressed as follows: C1ε = 1.44、 C 2ε = 1.92、 C μ = 0.09、 σ k =1.0 and σ ε = 1.3.

[0034] (iii) The energy change in the heat transfer domain of a thermoelectric power generation system can be described by the energy conservation equation, which is applicable to calculating the heat transfer in the solid heat transfer domain of a thermoelectric power generation system:

[0035] Step (3) determines the various boundary conditions required for this example: the mass flow rate and inlet temperature of the natural gas heavy truck exhaust, the flow rate and inlet temperature of the cooling water, etc. The boundary conditions for this example are shown in Table 3: Table 3 Boundary Conditions

[0036] Step (4), determine the required heat exchanger outlet temperature range 425 o C< T <450 o C. Based on the above differential equations and boundary conditions, the exhaust temperature at the heat exchanger outlet can be calculated using the finite element software COMSOL. T 0=489.09 o C, T 0 > 450 o C determines the length of the heat exchanger. L 1= L + i ×Δ l Width is W 1= W + y ×Δ w Table 4 lists the length, width, and outlet temperature of the heat exchanger for each iteration.

[0037] Table 4. Results obtained in each iteration

[0038] As shown in Table 4, after 5 iterations, i It has reached its maximum limit, at which point the exhaust outlet temperature is 451.79°C. o C still does not meet the requirements. Therefore, the next iteration begins by calculating the width of the heat exchanger, and it is found that when... i = 5, yWhen the value is 1, the exhaust outlet temperature is 438.63°C. o When C meets the requirement, the iteration ends. At this point, the length and width of the heat exchanger are 725 mm and 302 mm, respectively.

[0039] In particular, the above embodiments are only used to explain the present invention in detail. The various steps and modules of the present invention can be varied within a certain range. Based on the technical solution of the present invention, any improvements or equivalent transformations to individual steps and modules made in accordance with the principles of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A device for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system, characterized in that, The system includes a connector, heat exchanger, connecting pipe, water-cooled plate, fins, and a thermoelectric module. The connector is connected to the front and rear ends of the heat exchanger via connecting pipes. The lower surface of the thermoelectric module is attached to the heat exchanger, and the upper surface is attached to the S-shaped water-cooled plate. The heat exchanger is installed between the catalytic converter and the muffler of a natural gas heavy-duty truck to absorb the high-temperature heat from the engine exhaust. The heat exchanger is a modular structure composed of several longitudinally and laterally combinable sub-units. Each sub-unit has aluminum plate fins inside to enhance heat transfer. The total length and width of the heat exchanger can be adjusted between adjacent sub-units. The thermoelectric module is attached to the outer surface of the heat exchanger and is in thermal contact with the water-cooled plate of the S-shaped cooling water channel, forming a thermoelectric power generation unit. The number and arrangement of the sub-units can be adjusted.

2. The device for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system according to claim 1, characterized in that, The heat exchanger is an aluminum square structure with a length, width, and height of [missing information]. L 1. W 1 and H 1. Wall thickness is δ The connecting pipes before and after the heat exchanger are of the same type and have the same diameter. D 1. The appropriate size can be selected according to the diameter of the exhaust pipe.

3. The device for reducing the exhaust heat load of natural gas heavy trucks using a thermoelectric power generation system according to claim 1, characterized in that, The length and width of the thermoelectric module are both L 3. Neatly arranged on the upper and lower surfaces of the heat exchanger, with a longitudinal spacing of [missing information]. l The horizontal spacing is d 2; The thermoelectric module consists of a ceramic plate, copper electrodes, a P-type semiconductor and an N-type semiconductor. The upper and lower ends of the P-type semiconductor and the N-type semiconductor are connected in series through the copper electrodes and sandwiched between the upper and lower ceramic plates.

4. The device for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system according to claim 1, characterized in that, The heat exchanger is internally fitted with a thickness of t The height is H 3, length is L 3 aluminum plate fins, and at a spacing d 1. Neatly arranged in the exhaust gas passage of the heat exchanger, among which H 3= H 1-2 δ , L 3= L 1-2 l .

5. The device for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system according to claim 1, characterized in that, The length of the water-cooled plate is L 2, thickness is H 2, width is W 2. The length of the water-cooled plate is equal to the length of the heat exchanger, i.e. L 2 = L 1, and its width is half the width of the heat exchanger, that is W 2 = W 1 / 2; The water-cooled plate is provided with an S-shaped cooling water channel for introducing cooling water, and the diameter of the S-shaped cooling water channel is [missing information]. D 2.

6. A method for reducing the exhaust heat load of natural gas heavy-duty trucks using a thermoelectric power generation system as described in claim 1, characterized in that, A set of differential equations is established to predict the temperature of the thermoelectric power generation system, and boundary conditions are set appropriately to calculate the exhaust temperature at the heat exchanger outlet. For the length of the heat exchanger L 1. Perform iterative calculations; if in the number of iterations... i satisfy i ≤ n / 2 If the requirement is met, the iteration process ends; If the number of iterations reaches i = n / 2 If the conditions are still not met, the width of the heat exchanger is iteratively calculated until the requirements are met, and the length of the heat exchanger is calculated accordingly. L 1 = L ± i × l ,in L This is the initial length of the heat exchanger. i The number of iterations to be determined when determining the length of the heat exchanger. l The length of the heat exchanger is the change in length during each iteration of the calculation; the width of the heat exchanger. W 1 = W ± y × w in W This is the initial width of the heat exchanger. y The number of iterations to be determined when determining the width of the heat exchanger. w This represents the width change value of the heat exchanger during each iteration of the calculation.

7. The method according to claim 6, characterized in that, The heat exchanger is divided into several sub-units along its longitudinal direction based on the number of rows of thermoelectric modules. Each sub-unit includes a row of thermoelectric modules and half of the space between them. The initial structure of the heat exchanger consists of n sub-units, named N1, N2, N3...N n-1 N n During the iterative calculation, the length of the heat exchanger changes according to the length of one sub-unit each time, i.e. l = l / 2 + L 2 + l / 2, and the number of iterations is limited to satisfy i ≤ n / 2 .

8. The method according to claim 6, characterized in that, The heat exchanger is divided into several sub-units along the transverse direction based on the number of rows of thermoelectric modules. Each sub-unit includes a row of thermoelectric modules and the modules before and after it. d The initial structure of the heat exchanger consists of m sub-units, named K1, K2, K3...K, with a 2 / 2 interval. m-1 K m During the iterative calculation, the width of the heat exchanger changes according to the length of a sub-unit each time, i.e. w = d 2 / 2 + L 2 + d 2 / 2.

9. The method according to claim 6, characterized in that: First, consider the length of the heat exchanger. L 1. Perform iterative calculations; if the number of iterations... i satisfy i ≤ n / 2 If the requirement is met, the iteration process ends; If the number of iterations reaches i = n / 2 If the conditions are still not met, the width of the heat exchanger is iteratively calculated until the requirements are met.

10. The method according to claim 6, characterized in that, The final length and width of the heat exchanger are determined by selecting the desired exhaust outlet temperature conditions. T 1 < T < T 2) Firstly in i Calculate the exhaust outlet temperature of the heat exchanger in its initial state when = 0. T 0, and determine T Does 0 satisfy this temperature range? If not satisfied, then according to T 0 deviation T 1 and T Adjustment for case 2, i.e., when T 0 < T 1 hour setting L 1 = L - i ×Δ l , W 1 = W - y ×Δ w , and when T 0 > T 2 hours L 1 = L + i ×Δ l , W 1 = W + y ×Δ w Then let i = i +1, return to recalculate exhaust outlet temperature T i Check again whether it meets the requirements. T 1 < T i < T 2. The loop continues until the condition is met; if in i achieve n / 2 If the condition is still not met, then the width of the heat exchanger will be iterated, starting from... y = Increment from 1, and calculate the corresponding temperature. T i+y until satisfied T 1 < T i+y < T 2. This determines the final length and width of the heat exchanger.

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