A commutation coupled Stirling power system, design method and operation method thereof

Abstract

The application provides a reversing-coupled Stirling power system, a design method and an operation method, comprising two sets of Stirling power subsystems; a heat side channel and a cold side channel are arranged in a regenerative heat exchanger, the heat side channel is specially used for containing regenerative heat-releasing working medium, the cold side channel is specially used for containing regenerative heat-releasing working medium, the heat side channel and the cold side channel respectively form a stable temperature gradient therein, the pipeline life is improved, and the system safety is high; the Stirling power subsystem comprises a heater, a piston assembly and a cooler, a first end of the heater is connected with an expansion chamber, a first end of the cooler is connected with a compression chamber, through reversing switching, the two sets of Stirling power subsystems can switch the connection state with the heat side channel and the cold side channel, the two sets of Stirling power subsystems can use the same regenerative heat exchanger, and the heat side channel and the cold side channel therein can be efficiently switched to meet the demand of the Stirling power subsystem on the heat exchange area under different regenerative states.

Description

Technical Field

[0001] The present invention belongs to the technical field of Stirling engines, and in particular relates to a reversing coupled Stirling power system, a design method and an operating method thereof. Background Art

[0002] Since its introduction, the Stirling cycle has been widely sought after due to its characteristic of being a "generalized Carnot cycle." However, traditional Stirling engines all use heat storage devices as regenerators, which require the regenerator to have the advantages of large heat capacity, good heat storage capacity, and low flow resistance, posing a significant challenge to the design of the regenerator. After more than a hundred years of development, the overall performance of conventional Stirling regenerators remains unsatisfactory. Not only does it increase system resistance, it also significantly increases the heat transfer temperature difference. Ultimately, due to its complex components, high cost, and low efficiency, it is difficult to promote it on a large scale.

[0003] Recently, some scholars have proposed the idea of ​​using two parallel Stirling engine heat exchangers as regenerators, intending to replace the complex heat storage and regeneration system through heat exchange. However, due to the huge volume difference between the Stirling engine's heat release process and the heat absorption process, no matter how the heat exchanger is designed, it cannot meet the high heat recovery effect of the entire cycle of the coupled system. As a result, this idea has not seen any subsequent in-depth research, let alone application in actual engineering. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a reversing coupled Stirling power system, a design method and an operating method thereof, which are mainly used to solve the problem in the prior art that the heat exchanger cannot take into account the use scenarios of two parallel Stirling engines.

[0005] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0006] In a first aspect, the present invention provides a reversing coupled Stirling power system, comprising:

[0007] It comprises two Stirling power subsystems, and the two Stirling power subsystems share one regenerative heat exchanger;

[0008] The regenerative heat exchanger is provided with a hot side channel and a cold side channel. The hot side channel is used to accommodate the flow of working fluid of the Stirling power subsystem in the regenerative heat release process, and the cold side channel is used to accommodate the flow of working fluid of the Stirling power subsystem in the regenerative heat release process.

[0009] In some embodiments, the heat exchange area of ​​the hot side channel is larger than the heat exchange area of ​​the cold side channel.

[0010] In some embodiments, the Stirling power subsystem includes a heater, a piston assembly and a cooler, the first end of the heater is connected to the expansion chamber of the piston assembly, the first end of the cooler is connected to the compression chamber of the piston assembly, the piston assembly is connected to the transmission system, and the second end of the heater and the second end of the cooler switch their connection states with the hot side channel and the cold side channel of the heat recovery exchanger according to the heat recovery state of their corresponding Stirling power subsystems.

[0011] In some embodiments, the system further comprises a first reversing valve and a second reversing valve; the two Stirling power subsystems are respectively the first power subsystem and the second power subsystem;

[0012] The second ends of the coolers of the first power subsystem and the second power subsystem are connected to the first end of the hot side channel and the first end of the cold side channel via the first reversing valve in a switchable flow direction;

[0013] The second ends of the heaters of the first power subsystem and the second power subsystem are connected to the second end of the hot-side channel and the second end of the cold-side channel via the second reversing valve in a switchable flow direction.

[0014] In some embodiments, a synchronous control device is further included, which is electrically connected to the first reversing valve and the second reversing valve, respectively, and is used to control the first reversing valve and the second reversing valve to synchronously switch the flow state.

[0015] In some embodiments, the heaters of the two power subsystems are heated by the same constant temperature heat source.

[0016] In some embodiments, the constant temperature heat source is heat provided directly or indirectly by geothermal energy or solar energy.

[0017] In a second aspect, the present invention provides a design method for a reversing coupled Stirling power system, which is applied to a reversing coupled Stirling power system as described above, wherein the ratio of the working fluid volume of the Stirling power subsystem in the regenerative heat release process to the working fluid volume in the regenerative heat heating process is R1;

[0018] In the regenerative heat exchanger, the ratio of the heat exchange area of ​​the hot side channel to the heat exchange area of ​​the cold side channel is R2;

[0019] Among them, R1 / R2∈[0.5,1.5].

[0020] In a third aspect, the present invention provides an operating method for a reversing coupled Stirling power system as described above, wherein each Stirling power subsystem includes four processes: constant temperature expansion, constant volume heat release, constant temperature compression, and constant volume heat absorption. Two Stirling power subsystems are coupled with a half-cycle difference in period and share a regenerative heat exchanger.

[0021] When one set of Stirling power subsystems is in a constant temperature expansion process, the other is in a constant temperature compression process;

[0022] When one Stirling power subsystem is in a constant volume heat absorption process, the other is in a constant volume heat release process;

[0023] The regenerative heat exchanger couples the constant volume heat absorption and constant volume heat release processes of the two Stirling power subsystems during the constant volume heat regeneration process.

[0024] In some embodiments, the motion state of the piston assembly in the Stirling power subsystem is detected to determine the operating state of each Stirling power subsystem;

[0025] The Stirling power subsystem after controlling the regenerative heat release and before the regenerative heat heating is connected to the cold side channel of the regenerative heat exchanger;

[0026] The Stirling power subsystem after controlling the regenerative heating and before controlling the regenerative heat release is connected to the hot side channel of the regenerative heat exchanger.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects:

[0028] By switching, the two Stirling power subsystems can switch their connection status with the hot-side channel and the cold-side channel, so that the two Stirling power subsystems can be coupled to use the same heat exchanger and efficiently switch and utilize the hot-side channel and the cold-side channel to meet the heat exchange area requirements of the Stirling power subsystem under different heat recovery states;

[0029] By setting up a hot side channel and a cold side channel in the regenerative heat exchanger, the hot side channel is specifically used to accommodate the regenerative heat-releasing working medium, and the cold side channel is specifically used to accommodate the regenerative heat-reheating working medium. Stable temperature gradients are formed in the hot side channel and the cold side channel respectively, which improves the life of the pipeline and has high system safety. It avoids the phenomenon of high and low temperature reciprocating switching on both sides of the heat exchange in the regenerative heat exchanger, further reduces alternating thermal stress, and reduces low-cycle fatigue of the heat exchanger pipe.

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention is further described with reference to the accompanying drawings. However, the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall structure of a reversing coupled Stirling power system provided in this embodiment.

[0033] Figure 2 Schematic diagram of the structure of a reversing coupled Stirling power system in a reversing state provided by this embodiment.

[0034] Figure 3 3 is a schematic structural diagram of a reversing coupled Stirling power system provided by this embodiment in another reversing state. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] In the description of the present invention, when a specific device is described as being located between a first device and a second device, an intervening device may or may not be present between the specific device and the first device or the second device. When a specific device is described as being connected to another device, the specific device may be directly connected to the other device without an intervening device, or may be directly connected to the other device but with an intervening device.

[0038] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0039] Reference Figures 1 to 3 In a first aspect, an embodiment of the present invention provides a reversing coupled Stirling power system, comprising:

[0040] It includes two Stirling power subsystems coupled via a regenerative heat exchanger 116, and the two Stirling power subsystems share the same regenerative heat exchanger 116;

[0041] The regenerative heat exchanger 116 is provided with a hot side channel 10 and a cold side channel 20. The hot side channel 10 is used to accommodate the flow of working fluid of the Stirling power subsystem in the regenerative heat release process, and the cold side channel 20 is used to accommodate the flow of working fluid of the Stirling power subsystem in the regenerative heat heating process.

[0042] The Stirling power subsystem includes a heater 4, a piston assembly and a cooler 115. The first end of the heater 4 is connected to the expansion chamber 114 of the piston assembly, the first end of the cooler 115 is connected to the compression chamber 112 of the piston assembly, and the piston assembly is connected to the transmission system. The second end of the heater 4 and the second end of the cooler 115 switch their connection states with the hot side channel 10 and the cold side channel 20 of the heat recovery heat exchanger 116 according to the heat recovery state of their corresponding Stirling power subsystem.

[0043] Preferably, the thermal performance of the two Stirling power subsystems is completely consistent.

[0044] The specifications and functions of the heater 4, piston assembly and cooler 115 of the two Stirling power subsystems are the same. Since each Stirling power subsystem operates in a cycle according to the four processes of constant temperature expansion, constant volume heat release, constant temperature compression and constant volume heat absorption, if the two Stirling power subsystems are to be connected in parallel and share a heat recovery heat exchanger 116, then the heat recovery heat exchanger 116 needs to be used to be compatible with the different operating states of the two Stirling power subsystems.

[0045] Specifically, the two Stirling power subsystems require different heat exchange volumes and areas for the constant-volume heat absorption and constant-volume heat release processes during the constant-volume heat regeneration process. The heat exchange volume and area required for constant-volume heat release are larger, and the heat exchange volume and area required for constant-volume heat absorption are smaller. Therefore, the heat exchange area of ​​the hot side channel 10 is larger than the heat exchange area of ​​the cold side channel 20. The Stirling power subsystem in the heat regeneration and heat release process is connected to the hot side channel 10, so that its corresponding working fluid can be regenerated and released in the hot side channel 10 with a larger heat exchange area; the Stirling power subsystem in the heat regeneration and heating process is connected to the cold side channel 20, so that its corresponding working fluid can be regenerated and heated in the cold side channel 20 with a smaller heat exchange area.

[0046] Furthermore, according to the switching of the operating state of the Stirling power subsystem itself, the connection state between the Stirling power subsystem and the hot side channel 10 and the cold side channel 20 in the regenerative heat exchanger 116 is controlled.

[0047] Combine Figure 2 and Figure 3 As an embodiment, it further includes a first reversing valve 30 and a second reversing valve 40; the two Stirling power subsystems are respectively the first power subsystem and the second power subsystem;

[0048] The second ends of the coolers 115 of the first power subsystem and the second power subsystem are connected to the first ends of the hot side channel 10 and the cold side channel 20 via the first reversing valve 30 in a switchable manner;

[0049] The second ends of the heaters 4 of the first power subsystem and the second power subsystem are connected to the second ends of the hot side channel 10 and the cold side channel 20 via a second reversing valve 40 in a switchable manner.

[0050] Combine Figure 2 When the first power subsystem is in the regenerative heat release process and the second power subsystem is in the regenerative heating process, the first reversing valve 30 and the second reversing valve 40 are both controlled to be in the first flow state:

[0051] The second end of the cooler 115 of the first power subsystem is connected to the first end of the hot-side channel 10 through the first reversing valve 30, so that the working medium flows through the hot-side channel 10 and then flows out from the second end thereof. After releasing heat, the working medium flows through the second reversing valve 40 into the second end of the corresponding heater 4, completing the heat recovery and heat release process.

[0052] The second end of the heater 4 of the second power subsystem is connected to the second end of the cold side channel 20 through the second reversing valve 40, so that the working medium flows through the cold side channel 20 and then flows out from its first end. After the working medium is heated, it flows into the second end of the corresponding cooler 115 through the first reversing valve 30, completing the heat recovery heating process.

[0053] Combine Figure 3 When the regenerative states of the first power subsystem and the second power subsystem switch, and the second power subsystem is in the regenerative heat release process and the first power subsystem is in the regenerative heating process, the first reversing valve 30 and the second reversing valve 40 are both controlled to be in the second flow state:

[0054] The second end of the cooler 115 of the second power subsystem is connected to the first end of the hot-side channel 10 through the first reversing valve 30, so that the working medium flows through the hot-side channel 10 and then flows out from the second end thereof. After releasing heat, the working medium flows through the second reversing valve 40 into the second end of the corresponding heater 4, completing the heat recovery and heat release process.

[0055] The second end of the heater 4 of the first power subsystem is connected to the second end of the cold side channel 20 through the second reversing valve 40, so that the working medium flows through the cold side channel 20 and then flows out from its first end. After the working medium is heated, it flows into the second end of the corresponding cooler 115 through the first reversing valve 30, completing the heat recovery heating process.

[0056] As an implementation, a synchronization control device is further included, which is electrically connected with the first reversing valve 30 and the second reversing valve 40 respectively, and is used for controlling the first reversing valve 30 and the second reversing valve 40 to switch the flow state synchronously, so as to ensure that the hot side passage 10 and the cold side passage 20 of the regenerative heat exchanger 116 correspond to one Stirling power subsystem respectively at the same time, and the working medium is prevented from flowing between the two Stirling power subsystems.

[0057] In the second aspect, the embodiment of the present application provides a design method of a reversing coupled Stirling power system, which is applied to the reversing coupled Stirling power system as described above, and specifically:

[0058] The ratio of the working medium volume in the regenerative heat release process to the working medium volume in the regenerative heat absorption process of the Stirling power subsystem is R1;

[0059] The ratio of the heat exchange area of the hot side passage 10 to the heat exchange area of the cold side passage 20 in the regenerative heat exchanger 116 is R2;

[0060] Wherein, R1 / R2∈[0.5, 1.5].

[0061] As an implementation, the heaters 4 of the two sets of Stirling power subsystems are heated by the same constant temperature heat source, and the heaters are in the same heat source space, which is directly or indirectly provided with heat by a geothermal source or solar energy.

[0062] Since the geothermal source is very stable, a relatively constant temperature heat source space can be constructed, and the heaters 4 of the two sets of Stirling power subsystems are placed in the same constant temperature heat source space, which helps to keep the thermal performance of each subsystem consistent, so as to maximize the efficiency of the regenerative heat exchanger 116.

[0063] In particular, the heat source space is controlled at a set temperature, and the volume ratio R1 is determined by the ratio of the working medium volume in the regenerative heat release process to the working medium volume in the regenerative heat absorption process at the set temperature.

[0064] In the third aspect, the embodiment of the present application provides an operation method of a reversing coupled Stirling power system as described above, each set of Stirling power subsystems includes four processes of constant temperature expansion, constant volume heat release, constant temperature compression and constant volume heat absorption, and the two sets of Stirling power subsystems are coupled to share one regenerative heat exchanger 116 with a half cycle period difference;

[0065] When one set of Stirling power subsystems is in the constant temperature expansion process, the other set is in the constant temperature compression process.

[0066] When one set of Stirling power subsystems is in the constant volume heat absorption process, the other set is in the constant volume heat release process.

[0067] The regenerative heat exchanger 116 couples the constant volume heat absorption and constant volume heat release processes of the two Stirling power subsystems during the constant volume heat regeneration process.

[0068] It should be noted that the above-mentioned four processes of constant temperature expansion, constant volume heat release, constant temperature compression, and constant volume heat absorption are summarized for the convenience of understanding and explanation. During the actual operation process, due to inevitable influencing factors, those skilled in the art can understand them as approximate four processes of constant temperature expansion, constant volume heat release, constant temperature compression, and constant volume heat absorption.

[0069] The operating principle of each Stirling power subsystem is as follows: After the working fluid is heated by the hot steam from the heat extraction well in the heater 4, the displacement piston 113 moves upward, achieving constant-temperature expansion in the expansion chamber 114 and performing external work. Then, under the action of the displacement piston 113, the working fluid passes through the regenerative heat exchanger 116 and enters the compression chamber 112, releasing heat at a constant volume. The working fluid entering the compression chamber 112 is condensed by the cooler 115, and the power piston 111 moves downward, achieving constant-temperature compression in the compression chamber 112 and performing external negative work. Similarly, under the action of the displacement piston 113, the working fluid passes through the regenerative heat exchanger 116 again, from the compression chamber 112 to the expansion chamber 114, absorbing heat at a constant volume, completing the entire cycle. The power piston 111 is connected to the piston rod 117.

[0070] The two Stirling power subsystems are coupled via a regenerative heat exchanger 116. Each Stirling power subsystem operates according to the aforementioned principles. The entire Stirling power system operates as follows: while one Stirling power subsystem is in a constant-temperature expansion process, the other is in a constant-temperature compression process; while one is in a constant-volume heat absorption process, the other is in a constant-volume heat release process. While the two Stirling power subsystems are in the constant-volume heat absorption and constant-volume heat release processes, respectively, the working fluid in the two Stirling power subsystems achieves direct surface heat transfer in the regenerative heat exchanger 116, completing the heat exchange process.

[0071] The two Stirling power subsystems in the Stirling power system are coupled together through a high-efficiency regenerative heat exchanger 116 to achieve mutual heat exchange of the working fluid during the regenerative process, and each completes the cycle process in a different phase and is connected to the transmission system to generate electricity.

[0072] In this embodiment, the motion state of the piston assembly in the Stirling power subsystem is detected to determine the operating state of each Stirling power subsystem. The position and motion process of the piston assembly are used to determine whether the corresponding Stirling power subsystem is in the regenerative heat release process or the regenerative heating process.

[0073] The Stirling power subsystem after controlling the regenerative heat release and before the regenerative heat heating is connected to the cold side channel 20 of the regenerative heat exchanger 116;

[0074] The Stirling power subsystem after controlling the regenerative heating and before the regenerative heat release is connected to the hot side channel 10 of the regenerative heat exchanger 116 .

[0075] The above judgment result is used to control the switching of the flow states of the first reversing valve 30 and the second reversing valve 40 to improve the control accuracy.

[0076] In summary, compared to the prior art, the above embodiments provide a reversing coupled Stirling power system, design method, and operating method thereof. Through reversing switching, the two Stirling power subsystems can switch their connection states with the hot-side channel 10 and the cold-side channel 20, so that the two Stirling power subsystems can be coupled and use the same regenerative heat exchanger 116, and efficiently switch and utilize the hot-side channel 10 and the cold-side channel 20 therein, thereby meeting the heat exchange area requirements of the Stirling power subsystems under different regenerative states.

[0077] By separately providing a hot side channel 10 and a cold side channel 20 in the regenerative heat exchanger 116, the hot side channel 10 is specifically used to accommodate the regenerative heat-releasing working medium, and the cold side channel 20 is specifically used to accommodate the regenerative heat-releasing working medium. Stable temperature gradients are formed in the hot side channel 10 and the cold side channel 20 respectively, thereby improving the life of the pipeline and increasing the system safety. The phenomenon of high and low temperature reciprocating switching on both sides of the heat exchange in the regenerative heat exchanger 116 is avoided, and the alternating thermal stress is further reduced, thereby reducing the low-cycle fatigue of the heat exchanger pipe.

[0078] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A commutation coupled Stirling power system, characterized in that: include: Two Stirling power subsystems, the two Stirling power subsystems sharing a regenerative heat exchanger; The regenerative heat exchanger is provided with a hot side channel and a cold side channel. The hot side channel is used to accommodate the flow of working fluid of the Stirling power subsystem in the regenerative heat release process, and the cold side channel is used to accommodate the flow of working fluid of the Stirling power subsystem in the regenerative heat heating process. The heat exchange area of ​​the hot side channel is larger than the heat exchange area of ​​the cold side channel; The Stirling power subsystem also includes a heater, a piston assembly and a cooler. The first end of the heater is connected to the expansion chamber of the piston assembly, the first end of the cooler is connected to the compression chamber of the piston assembly, and the piston assembly is connected to the transmission system. The second end of the heater and the second end of the cooler switch their connection states with the hot side channel and the cold side channel of the heat recovery exchanger according to the heat recovery state of their corresponding Stirling power subsystems.

2. A commutation coupled Stirling power system according to claim 1, characterized in that: It also includes a first reversing valve and a second reversing valve; the two sets of Stirling power subsystems are respectively the first power subsystem and the second power subsystem; The second ends of the coolers of the first power subsystem and the second power subsystem are connected to the first end of the hot side channel and the first end of the cold side channel via the first reversing valve in a switchable flow direction; The second ends of the heaters of the first power subsystem and the second power subsystem are connected to the second end of the hot-side channel and the second end of the cold-side channel via the second reversing valve in a switchable flow direction.

3. A reversing coupled Stirling power system according to claim 2, characterized in that: It also includes a synchronous control device, which is electrically connected to the first reversing valve and the second reversing valve respectively, and is used to control the first reversing valve and the second reversing valve to synchronously switch the flow state.

4. A reversing coupled Stirling power system according to any one of claims 1 to 3, characterized in that: The heaters of the two power subsystems are heated by the same constant temperature heat source.

5. A reversing coupled Stirling power system according to claim 4, characterized in that: The constant temperature heat source is heat provided directly or indirectly by geothermal energy or solar energy.

6. A design method for a commutation-coupled Stirling power system, applied to a commutation-coupled Stirling power system according to any one of claims 1 to 5, characterized in that: The ratio of the working fluid volume of the Stirling power subsystem in the regenerative heat release process to the working fluid volume in the regenerative heat heating process is R1; In the regenerative heat exchanger, the ratio of the heat exchange area of ​​the hot side channel to the heat exchange area of ​​the cold side channel is R2; Where R1 / R2∈[0.5, 1.5].

7. An operating method for a reversing coupled Stirling power system according to any one of claims 1 to 5, characterized in that: Each set of the Stirling power subsystem includes four processes: constant temperature expansion, constant volume heat release, constant temperature compression, and constant volume heat absorption. The two sets of the Stirling power subsystems are coupled with a half cycle difference and share a heat regeneration heat exchanger. When one set of Stirling power subsystems is in a constant temperature expansion process, the other is in a constant temperature compression process; When one Stirling power subsystem is in a constant volume heat absorption process, the other is in a constant volume heat release process; The regenerative heat exchanger couples the constant volume heat absorption and constant volume heat release processes of the two Stirling power subsystems during the constant volume heat regeneration process.

8. The operating method according to claim 7, characterized in that: detecting the motion state of the piston assembly in the Stirling power subsystem and determining the operating state of each Stirling power subsystem; The Stirling power subsystem after controlling the regenerative heat release and before the regenerative heat heating is connected to the cold side channel of the regenerative heat exchanger; The Stirling power subsystem after controlling the regenerative heating and before controlling the regenerative heat release is connected to the hot side channel of the regenerative heat exchanger.

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