Bridge type thermal rectifier

A thermal rectifier and bridge technology, applied in the field of bridge thermal rectifiers, to achieve the effect of improving energy conversion efficiency

Active Publication Date: 2021-08-17
SOUTHEAST UNIV
10 Cites 1 Cited by

AI-Extracted Technical Summary

Problems solved by technology

[0004] The present disclosure provides a bridge-type thermal rectifier, whose technical purpose is to solve the problem of obtaining constant power output from a heat source that changes with time, and can solve the problem of uninterrupted out...
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Method used

The heat capacity involved in the present invention is defined as C, and its working mechanism is to select a material with good thermal conductivity, usually metal, which can quickly heat and cool down, while the heat capacity and th...
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Abstract

The invention discloses a bridge type thermal rectifier, relates to the technical field of engineering thermophysics, and solves the technical problem that constant power output cannot be obtained from a heat source changing along with time. The main points of the technical scheme are that a first heat energy absorption/release plate is heated to obtain high temperature; the first heat capacity is heated by positively biasing the first heat diode directed to the first heat capacity, and the second heat capacity cannot be heated by the first heat energy absorption/release plate due to reverse biasing of the second heat diode, so the first heat capacity will be maintained at a higher temperature while the second heat capacity is maintained in a low temperature state. Along with weakening of the heat source, when the temperature of the first heat energy absorption/release plate continues to drop and drops below the second heat capacity temperature, waste heat obtained by the second heat capacity from work of the heat engine can flow through the first heat energy absorption/release plate from the second heat diode to be dissipated to the outside. After a plurality of cycles, the first heat capacity and the second heat capacity are respectively maintained at a relatively stable temperature, so that stable output is continuously carried out by virtue of the heat engine.

Application Domain

From solar energyMachines/engines +2

Technology Topic

EngineeringHeat engine +10

Image

  • Bridge type thermal rectifier
  • Bridge type thermal rectifier
  • Bridge type thermal rectifier

Examples

  • Experimental program(1)

Example Embodiment

[0023] The present disclosure will be described in detail below with reference to the accompanying drawings. In the description of the present invention, it is to be understood that the terms "first", "second", "third", "fourth" are only used for description purposes, and cannot be understood as indication or hinting relative importance or hidden. Include the number of technical features indicated, it is only used to distinguish between different components.
[0024] Further, the thermal diode according to the present invention has the working mechanism of which is: when the external temperature difference is consistent with the hot diode offset direction, the thermal diode heat resistance is small, defined as R Fwd. The heat flow can quickly transfer from the hot end by the thermal diode from the hot end, when the external temperature difference is opposite to the hot diode bias direction, the thermal diode heat resistance is large, defined as R Rev. The heat flow cannot be effectively transferred from the hot end to the cold end, and the function of one-way thermal conductivity is achieved.
[0025] The heat capacity according to the present invention is defined as c, its working mechanism is a material having good thermal conductivity, usually metal, can quickly heat and cool down, while heat capacity is well insulated from the outside to maintain a relative Stable temperature. The first heat capacity 21 is maintained at a high temperature TH, and the second heat capacity 22 is maintained at a low temperature Tc.
[0026] The thermal machine (may be any type) of the present invention, the working mechanism is, one end connecting the heat source, one end connecting the cold source, using both end temperature differences, can directly output mechanical energy, can also output electrical energy. The working thermal resistance of the heat machine is defined as R Engine.
[0027] figure 1 First showing the bridge heat rectifier of the present invention, such as figure 1 As shown, the rectifier comprises a thermal diode bridge, a first thermal energy absorption / release plate 11, a first heat capacity 31, a second heat capacity 32, and a thermal diode bridge including a first thermal diode 21 and a second thermal diode. 22. Both the first thermal diode 21 and the second thermal diode 22 include a forward biasing end and a reverse bias end, the reverse bias end to the direction of the forward bias. Offset, the forward bias end to the direction in which the reverse bias end is reverse biass. The forward bias end of the first thermal diode 21 is connected to the first heat capacity 31, and the reverse bias end is connected to the first thermal energy absorption / release plate 11; the second thermal diode 22 The bias end is connected to the first thermal energy absorption / release plate 11, and the reverse bias end is connected to the second heat capacity 32. One end of the heat engine 4 is connected to the first heat capacity 31, and the other end is connected to the second heat capacity 32.
[0028] figure 2 A second show for the bridge thermal rectifier of the present invention, such as figure 2 As shown, the bridge thermal rectifier except figure 1 In addition to the components shown, the second thermal absorption / release plate 12 also includes a third thermal diode 23 and a fourth thermal diode 24, the third thermal diode 23 and the fourth heat. The diode 24 includes the reverse bias end and the forward bias terminal. The forward bias end of the third thermal diode 23 is connected to the first heat capacity 31, and the reverse bias end is connected to the second thermal energy absorption / release plate 12; the fourth thermal diode 24 The bias end is connected to the second thermal absorption / release plate 12, and the reverse bias end is connected to the second heat capacity 32. One end of the heat engine 4 is connected to the first heat capacity 31, and the other end is connected to the second heat capacity 32.
[0029] The first thermal diode 21 is directed to the first heat capacity 31 to the first heat capacity 31, and the heat capacity can only be transmitted from the first thermal absorption / release plate 11 to the first heat capacity 31, and the second thermal diode 22 reverse biased point to the first heat The absorption / release plate 11 guarantees that heat can only be transmitted from the second heat capacity 32 to the first thermal energy absorption / release plate 11. Similarly, the second thermal absorption / release plate 12 connects the third thermal diode 23 and the fourth thermal diode 24, the third thermal diode 23 is connected to the first heat capacity 31 and the second thermal absorption / release plate 12, the fourth thermal diode 24 Connect the second heat capacity 22 and the second thermal absorption / release plate 12. The third thermal diode 23 is directed to the heat capacity 31 to ensure that the heat can only be transmitted from the second thermal absorption / release plate 12 to the first heat capacity 31, and the fourth heat diode 24 reverse bias points to the second thermal energy absorption / The release plate 12 ensures that heat can only be transmitted from the second heat capacity 32 to the second thermal energy absorption / release plate 12. The first heat capacity 31 and the second heat capacity 32 are connected by a heat engine 4, and the temperature difference drive heat engine 4 of the first heat capacity 31 and the second heat pipe 32 is used.
[0030] Depend on figure 1 , figure 2 It can be seen that if figure 2 For a full bridge structure, then figure 1 It can be seen as a half bridge structure. When the heat capacity of the bridge heat rectifier is large enough, the forward (reverse) is small (large) of the bias thermal resistance (large) in the thermal thermal resistance, the temperature th of the first heat capacity 31 will always be maintained at a higher than the second thermal energy absorption. / Release the plate 12 up to temperature, while the temperature Tc of the second heat capacity 32 will always be held at a temperature below the second thermal absorption / release plate 12, the second thermal absorption / release plate 12 will no longer participate The heat exchange of the entire system, that is, the second thermal absorption / release panel 12 can be considered, and the bridge heat rectifier can be simplified into a semi-bridge structure (corresponding to it. figure 2 The bridge heat rectifier shown is a full bridge structure, such as figure 1 , image 3 Indicated.
[0031] In the bridge structure, such as figure 2As shown, the two thermoelectric absorption / release plates of the bridge heat rectifier are input / output interfaces of the entire system, wherein the first thermal absorption / release plate 11 is the main energy exchange window, and the temperature is higher after it is heated by the outside. The first heat capacity 31 thereof is biased forward in the first thermal diode 21, and the heat is heated from the first thermal energy absorption / release plate 11 through the first thermal diode 21; when the external temperature is low When the first thermal absorption / release plate 11 temperature is lower than the first heat capacity 31 thereof, the forward biased first thermal diode 21 prevents heat reflow, and the heat of the first heat capacity 31 cannot pass through the first hot diode 21. The first thermal energy absorption / release plate 11 is lost, thereby ensuring that the first heat capacity 31 can maintain high temperatures. Conversely, when the first thermal absorption / release plate 11 temperature is higher than the second heat capacity 32, the second thermal diode 22 reverse biases, ensuring that the heat of the first thermal energy absorption / release plate 11 cannot be from the second thermal diode 22. The second heat capacity 32 is transmitted; and when the first thermal absorption / release plate 11 temperature is lower than the second heat capacity 32, the second thermal diode 22 in the reverse biased passes the heat of the second heat capacity 32 through the second heat. The diode 22 is released, thereby ensuring that the second heat capacity 32 can maintain a low temperature.
[0032] The second thermal absorption / release plate 12 is an auxiliary energy exchange window of the entire system. The heat source of contact is usually different from time to time varies with time, and its high and low temperature amplitude is generally less than the first heat. The high and low temperature amplitude of the absorption / release plate 11 is in contact with the heat source. The second thermal absorption / release plate 12 not only assumes the function of the auxiliary second heat capacity 32 heat dissipation, but also a supplement to the first heat pipe 31 heating. Similar to the first thermal absorption / release plate 11, the connected third thermal diode 23 is directed to the first heat capacity 31, and the fourth heat diode 24 reverse bias points to the second heat capacity 32. If the heat source in which the second thermal absorption / release plate is in contact with the heat source in contact with the first thermal energy absorption / release plate, the second thermal absorption / release plate will have the same function as the first thermal energy absorption / release plate, at this time The power output of the entire system is not large, but the rectification effect will become better, and its fluctuation error will reduce 1/4 of the half bridge mode.
[0033] As a specific embodiment, in order to maximize the efficiency of the bridge heat rectifier of the present invention, the first thermal energy absorbing / release plate can be designed as selective radiating board when developing solar energy. image 3 , Figure 4 The second heat absorption / release plate 12 is selected as the earth. The selective radiation plate requires a surface photon design, ie the wavelength of less than 2.5 microns, as far as possible, the photon greater than 2.5 microns is not absorbed as much as possible.
[0034] When the solar energy is developed, in order to maximize the first heat capacity 31 obtaining solar energy and maximum efficiency, the second heat capacity 32 is dissipated, the first thermal energy absorbing / release plate 11 uses a selective radiating plate, and the second thermal energy absorption / The release plate 12 is typically different from the solar cycle variation in the mainland, and its temperature is a relatively stable temperature T∞, also known as heat, such as Figure 4 Indicated. The selective radiation plate (first thermal absorption / release plate 11) heats the first heat pipe 21 to a relatively high temperature TH by the first thermal diode 21, which is usually higher than the heat sink temperature T∞, so the first heat capacity The heat of 31 does not flow through the third hot diode 13 to heat sink; at the same time, since the second thermal diode 22 is reverse biased, the selective radiating plate is prevented from heating the second heat capacity 32, so the second heat capacity 32 temperature should be low. In the first heat capacitor 31, we call it TC to ensure that the heatstream of the first heat capacity 31 can flow to the second heat capacity 32 through the heat engine; because the heat sink temperature is low, the second heat capacity 32 is from The waste heat obtained by the heat engine can be dissipated from the fourth thermal diode 14 to the heat sink. On the night, the selective radiation plate cannot obtain solar energy, but due to the heat dissipation of the deep space, the temperature is low, usually lower than the heat sink, so the heating process of the first heat capacity 31 is stopped, and the first heat capacity is output as the heat engine The temperature of 31 continues to decrease, and when the first heat capacity 31 temperature is lower than heat sink, the heat sink may be the first heat capacity 31 to replenish heat, and the waste heat obtained by the second heat pipe 32 will pass through the second thermal diode. 22 Dissive from the selective radiation plate to deep space, thereby ensuring that the heat machine can keep working 24 hours during the day.
[0035] When the system enters a stable change period, heat will no longer participate in heat exchange, and then the hot diode bridge can be simplified as half bridge mode, such as image 3 Indicated. In the semi-bridge structure, the solar energy conversion is used as an example, during the daylight heating the first thermal energy absorbing / release plate (in solar energy development, selective radiation plates typically use the high temperature, point to the first heat capacity 31 by forward bias 31 The first thermal diode 21 heats the first heat capacity 31, at which time the second heat diode 22 is reversed, the second heat capacity 32 cannot be heated by the first thermal energy absorption / release plate, so the first heat capacity 31 will remain In a higher temperature, the second heat capacity 32 remains at a low temperature. The heat engine 4 relies on the temperature difference of the first heat capacity 31 and the second heat pipe 32. As the solar energy is reduced, the temperature of the first thermal absorption / release plate gradually decreases to the temperature below the first heat capacity 31, at which time the first thermal diode 21 is closed, the heat flow cannot be lost from the first heat capacity 31 to the first thermal energy absorption / The release plate is therefore the first heat capacitor 31 continues to maintain a high temperature. When the first thermal absorption / release plate temperature continues to fall, lower to the second heat capacity 2 temperature, the waste heat obtained from the thermal machine 4 will flow from the second thermal diode 22 through the first thermal energy absorption. The release plate is scattered to the outside world. After several cycles, the first heat capacity 31 and the second heat capacity 32 maintain each relatively stable temperature, and the temperature difference within each cycle is no longer fluctuating, so that it can continue to rely on the heat machine to stabilize .
[0036] As a specific embodiment, in order to maximize the efficiency of the bridge thermal rectifier, the front and reverse bias ratio of the thermal diode is, the better. However, in consideration of the performance of the actual thermal diode, the positive anti-bias is less than 0.01 less than 0.01 to achieve an ideal case. It is important to indicate that the key to increasing the power output of the bridge heat rectifier is to minimize the forward bias thermal resistance, and there is no strict requirement for the reverse bias thermal resistance, as long as it is greater than the thermal thermal resistance. For example, 70% of the maximum output power is to be reached. but I.e. (The forward bias rate is defined here as The reverse bias rate is defined as Positive anti-offset ratio is defined as R Fwd. / R Rev.. )
[0037] In order to maximize the efficiency of the device, the larger the heat capacity is, the better. However, considering that excessive heat accumulated in actual use, in order to be more than quasi-heat capacity (defined as Post-quasi-quantity 90% of the ideal case (here) C is a heat capacity, τ is a cycle of a heat source over time, such as the period of solar energy of 24 hours). The heat capacity unit Joule / Kelvin (J / K) is an absolutely magnitude, and the heat capacity is relatively compared with the nature of the cycle and heat capacity material of the entire system, not the specific material.
[0038] Under the above design requirements, the output fluctuations of the hot diode half bridge or the hot diode full bridge can be maintained within 10%, and a stable "DC" output is achieved. like Figure 5 As shown, the simulated selective hot radiation plate is during the day, the temperature cyclical changes in the night is sine wave, and the unmetable configuration is selected. The forward bias rate of the heat diode is 0.01, the reverse bias rate is 1, and the final output power fluctuation is only 8%. At this time, the output power of the thermal diode has reached more than 3 times the water heater mode (the theoretical limit is 4 times), and the thermal electrical device is achieved (the theoretical limit is 8 times).
[0039] The above is an exemplary embodiment of the present disclosure, and the scope of the present disclosure is defined by the claims and its equivalents.

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Classification and recommendation of technical efficacy words

  • Improve energy conversion efficiency
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