A heat-driven Stirling device and operation method thereof

Abstract

The invention discloses a heat-driven Stirling device, comprising a working chamber, an engine ejector, a heat pump ejector and a buffer chamber, wherein the engine ejector and the heat pump ejector are provided with ejector connecting rods, the ejector connecting rods extend into the buffer chamber, a connecting rod cylinder is provided on the outer periphery of the portion of at least one ejector connecting rod located in the buffer chamber, a sealed connecting rod actual force area adjustment chamber is formed between the connecting rod cylinder and the ejector connecting rod, a first switch valve is provided between the connecting rod actual force area adjustment chamber and the corresponding working chamber, and a second switch valve is provided between the buffer chamber and the connecting rod actual force area adjustment chamber. Its operation method is that when operating in a low-frequency mode, the first switch valve is opened and the second switch valve is closed, so that the connecting rod actual force area adjustment chamber is disconnected from the buffer chamber and connected to the corresponding working chamber; when operating in a high-frequency mode, the first switch valve is closed and the second switch valve is opened, so that the connecting rod actual force area adjustment chamber is connected to the buffer chamber and disconnected from the corresponding working chamber.

Description

Technical Field

[0001] The invention relates to the fields of engines, refrigerators and heat pumps, and in particular to a heat-driven Stirling device and an operating method thereof. Background Art

[0002] Compared with internal combustion engines, Stirling engines are external combustion engines with the advantages of high efficiency and the use of low-quality thermal energy. Compared with vapor compression cycle heat pumps, Stirling heat pumps have the advantages of high efficiency and environmentally friendly refrigerants. Therefore, the heat-driven Stirling device that uses a Stirling engine to drive a Stirling heat pump has huge market application space.

[0003] However, the existing heat-driven Stirling device has problems such as difficulty in adjusting the load and low efficiency under variable load. Since the temperature of the high-temperature heat exchanger of the Stirling engine needs to be greatly reduced under small load to adjust the heat load output of the heat-driven Stirling device, the problem of low efficiency is caused. In response to this problem, patent document CN105723165A discloses a four-process cycle for a Villemire heat pump, and proposes a method for controlling the static time of the ejector at the dead point position to adjust the load for the free piston structure. Due to the change of working conditions, it is difficult for the free running stroke of the ejector to reach the design stroke in the actual working condition, and it is easy to exceed or be less than the design stroke, resulting in collision or a large amount of power consumption, affecting the life and energy efficiency of the device. Moreover, for the heat-driven Stirling device based on the transmission mechanism, due to the lateral force between the cylinder wall and the connecting rod, it will cause wear, reduce reliability and affect the service life; for areas or time periods with low electricity prices, the existing heat-driven Stirling device also has the problem of high fuel costs. Patent document EP0629823A1 discloses a Villemire device, which can adjust the operating frequency through a volume control adjustment mechanism. However, the volume control adjustment mechanism requires not only a motor but also components such as gears. The overall structure is complex, the cost is high, and the reliability is reduced. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a heat-driven Stirling device with a simple structure, convenient frequency adjustment, improved operating efficiency and reliability, and reduced operating costs.

[0005] The present invention further provides an operation method of the above-mentioned heat-driven Stirling device.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A heat-driven Stirling device comprises a working chamber, an engine ejector, a heat pump ejector and a buffer chamber, wherein the working chamber is a low-temperature chamber, a low-temperature heat exchanger, a heat pump regenerator, a heat pump room-temperature heat exchanger, a heat pump room-temperature chamber, an engine room-temperature chamber, an engine room-temperature heat exchanger, an engine regenerator, a high-temperature heat exchanger and a high-temperature chamber, wherein the engine ejector and the heat pump ejector are provided with ejector connecting rods, wherein the ejector connecting rods extend into the buffer chamber, and a connecting rod cylinder is provided on the outer periphery of a portion of at least one ejector connecting rod located in the buffer chamber, and a closed connecting rod actual force area adjustment chamber is formed between the connecting rod cylinder and the ejector connecting rod, a first switch valve is provided between the connecting rod actual force area adjustment chamber and the corresponding working chamber, and a second switch valve is provided between the buffer chamber and the connecting rod actual force area adjustment chamber. It should be noted that the working chamber corresponding to the ejector connecting rod of the engine ejector can be an engine room temperature chamber, an engine room temperature heat exchanger, an engine regenerator, a high temperature heat exchanger or a high temperature chamber, while the working chamber corresponding to the ejector connecting rod of the heat pump ejector can be a low temperature chamber, a low temperature heat exchanger, a heat pump regenerator, a heat pump room temperature heat exchanger or a heat pump room temperature chamber.

[0008] As a further improvement of the above technical solution: the ejector connecting rod includes at least two coaxial rods and the diameters of two adjacent rods are different. Preferably, it includes multiple coaxial rods with different diameters, or the ejector connecting rod includes at least two rods with different axes. The connecting rod cylinder includes at least two inner holes and is arranged one by one with each rod section. Preferably, a seal is provided between each rod section and the corresponding inner hole. The seal may be, for example, a sealing ring.

[0009] As a further improvement of the above technical solution: the difference between the length of each segment rod and the corresponding ejector stroke is 0 to 10 cm, the difference between the length of each inner hole and the corresponding ejector stroke is 0 to 10 cm, and the difference between the diameter of each segment rod and the diameter of the corresponding inner hole is 0 to 2 mm.

[0010] As a further improvement of the above technical solution: both the engine ejector and the heat pump ejector are provided with ejector connecting rods, and a transmission mechanism is provided between the two ejector connecting rods.

[0011] As a further improvement of the above technical solution: the diameters of the two ejector connecting rods are different, and the connecting rod cylinder is arranged on the outer periphery of the ejector connecting rod with a larger diameter.

[0012] As a further improvement of the above technical solution: it also includes an electromagnetic drive mechanism for driving the ejector to move.

[0013] As a further improvement of the above technical solution: it also includes a working fluid storage tank, and a third switch valve is provided between the working fluid storage tank and the actual force area adjustment chamber of the connecting rod.

[0014] As a further improvement of the above technical solution: a fourth switch valve is further provided between the working fluid storage tank and the actual force area adjustment chamber of the connecting rod, an intake valve is provided between the third switch valve and the working fluid storage tank, and an exhaust valve is provided between the fourth switch valve and the working fluid storage tank.

[0015] A method of operating the above-mentioned heat-driven Stirling device includes a low frequency mode and a high frequency mode:

[0016] When operating in low-frequency mode, the actual force area adjustment chamber of the connecting rod is disconnected from the buffer chamber and connected to the corresponding working chamber;

[0017] When operating in high frequency mode, the actual force area adjustment cavity of the connecting rod is connected with the buffer cavity and disconnected from the corresponding working cavity.

[0018] As a further improvement of the above technical solution:

[0019] The device operates at the low frequency mode f1 for a time of t1 and at the high frequency mode f2 for a time of t2. By controlling the length of the time t1 and t2, the output load of the device during the time t1+t2 is equal to the demand load;

[0020] Or, first calculate the required operating frequency f R Then select the operating frequency f that is closest to the required R The operating frequency f i , required operating frequency f R With the natural operating frequency f i The difference between the two is supplemented by the electromagnetic drive mechanism, so that the device operates at a frequency of f R .

[0021] As a further improvement of the above technical solution:

[0022] Including working pressure regulation: when the working pressure is high and the output load exceeds the required load, during the process of reducing the volume of the connecting rod actual force area regulation chamber, the first switch valve and the second switch valve are closed, and when the pressure of the connecting rod actual force area regulation chamber is higher than the working fluid storage tank, the third switch valve is opened, and the working fluid storage tank is connected to the connecting rod actual force area regulation chamber; during the process of increasing the volume of the connecting rod actual force area regulation chamber, the first switch valve or the second switch valve is opened, the third switch valve is closed, and the working fluid storage tank is disconnected from the connecting rod actual force area regulation chamber.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] The heat-driven Stirling device disclosed in the present invention can change the actual force-bearing cross-sectional area of ​​the ejector connecting rod by controlling the actual force-bearing area adjustment cavity formed by the cooperation of the ejector connecting rod and the connecting rod cylinder, and connect or disconnect with the corresponding working cavity and the buffer cavity, thereby adjusting the frequency of the heat-driven Stirling device, without the need to set up components such as motors and gears, and has a simple structure, low cost, good reliability, and convenient adjustment, thereby ensuring that the high-temperature heat exchanger in the Stirling engine operates at a higher temperature, and improving the efficiency of the heat-driven Stirling device under non-rated working conditions; moreover, under a small demand load, the heat-driven Stirling device is controlled to operate under a smaller actual force-bearing area of ​​the ejector connecting rod, which can reduce the force on the ejector connecting rod, thereby reducing lateral force, reducing wear, and improving reliability; in addition, under the condition of relatively cheap electricity prices, the minimum actual force-bearing area of ​​the ejector connecting rod can be used, and the electric energy can be used to drive the ejector to move, thereby reducing operating costs.

[0025] The operating method of the heat-driven Stirling device disclosed in the present invention controls the on-off of the first switch valve and the second switch valve, thereby controlling the connection or disconnection between the actual force-bearing area adjustment chamber of the connecting rod and the corresponding working chamber and the buffer chamber, thereby changing the actual force-bearing cross-sectional area of ​​the ejector connecting rod and adjusting the frequency of the heat-driven Stirling device. The method is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 a is a schematic diagram of the structure of an existing free piston thermally driven Stirling device.

[0027] Figure 1 b is a schematic diagram of the structure of an existing heat-driven Stirling device with a transmission mechanism.

[0028] Figure 2 yes Figure 1 Schematic diagram of gas force analysis of the engine exhaust in a.

[0029] Figure 3 a to Figure 3 g is a schematic diagram of the structure of the ejector connecting rod and the connecting rod cylinder in the present invention.

[0030] Figure 4 a to Figure 4 b is Figure 3 Exploded view of a.

[0031] Figure 5 a to Figure 5 c is a schematic diagram of the structure of the connecting hole on the actual force-bearing area adjustment cavity of the connecting rod in the present invention.

[0032] Figure 6 It is a structural schematic diagram of the actual force-bearing area adjustment cavity of the connecting rod in the present invention.

[0033] Figure 7It is a structural schematic diagram of the ejector stroke in the present invention.

[0034] Figure 8 a to Figure 8 b is a schematic structural diagram of the first embodiment of the heat-driven Stirling device of the present invention.

[0035] Fig. 9 It is a schematic structural diagram of a second embodiment of the heat-driven Stirling device of the present invention.

[0036] Fig.10 It is a schematic structural diagram of the third embodiment of the heat-driven Stirling device of the present invention.

[0037] Fig.11 It is a schematic diagram of different operation modes of the operation method of the heat-driven Stirling device of the present invention.

[0038] Fig.12 It is a schematic flow chart of the operating method of the heat-driven Stirling device of the present invention.

[0039] The reference numerals in the figure indicate: 1. low temperature chamber; 2. low temperature heat exchanger; 3. heat pump regenerator; 4. heat pump room temperature heat exchanger; 5. heat pump room temperature chamber; 6. engine room temperature chamber; 7. engine room temperature heat exchanger; 8. engine regenerator; 9. high temperature heat exchanger; 10. high temperature chamber; 11. engine ejector; 12. heat pump ejector; 13. ejector connecting rod; 131. first ejector connecting rod; 132. second ejector connecting rod; 15. buffer chamber; 16. connecting rod cylinder; 17. actual force area adjustment of connecting rod Cavity; 171, first connecting rod actual force area adjustment cavity; 172, second connecting rod actual force area adjustment cavity; 18, cylinder partition; 181, first cylinder partition; 182, second cylinder partition; 21, connecting hole; 221, first switch valve; 222, second switch valve; 223, third switch valve; 224, fourth switch valve; 23, transmission mechanism; 24, working fluid storage tank; 241, intake valve; 242, exhaust valve; 25, electromagnetic drive mechanism; 26, sealing component; 27, control module. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Embodiment 1

[0042] Figure 1a is an existing free piston heat-driven Stirling device, comprising a working chamber, a buffer chamber 15, an engine ejector 11 and a heat pump ejector 12, wherein the working chamber can be a low-temperature chamber 1, a low-temperature heat exchanger 2, a heat pump regenerator 3, a heat pump room temperature heat exchanger 4, a heat pump room temperature chamber 5, an engine room temperature chamber 6, an engine room temperature heat exchanger 7, an engine regenerator 8, a high temperature heat exchanger 9 and a high temperature chamber 10, and the free piston heat-driven Stirling device also includes an ejector connecting rod 13 (the ejector corresponds to the engine ejector 11 and the heat pump ejector 12), wherein one end of a first ejector connecting rod 131 is fixed to the engine ejector 11, and the other end passes through the first cylinder partition 181 and extends into the buffer chamber 15, and one end of a second ejector connecting rod 132 is fixed to the heat pump ejector 12, and the other end passes through the second cylinder partition 182 and extends into the buffer chamber 15. Figure 1 b is an existing heat-driven Stirling device with a transmission mechanism 23, Figure 1 On the basis of a, the first ejector connecting rod 131 and the second ejector connecting rod 132 are connected by a transmission mechanism 23, and the transmission mechanism 23 can be a crank-connecting rod transmission mechanism, a diamond transmission mechanism or a Scotch yoke transmission mechanism, etc. Based on the thermal drive of the transmission mechanism 23, the engine ejector 11 and the heat pump ejector 12 in the Stirling device maintain a fixed operating phase. Figure 1 a. Figure 1 The operating frequency of the heat-driven Stirling device shown in b depends largely on the force-bearing area of ​​the ejector connecting rod 13 when the operating conditions are given.

[0043] like Figure 1 a and Figure 2 As shown, the gas force F of the engine exhauster 11 is the sum of the three gas forces Fw1, Fw2 and Fb:

[0044] F=F w1 +F w2 +F b

[0045] in,

[0046] F w1 =P w1 ·A w1

[0047] F w2 =P w2 ·A w2

[0048] F b =P b ·A r

[0049] In the above formulas, F is force, P is pressure, A is area, subscripts w and b refer to the working chamber and the buffer chamber 15 respectively, subscripts w1 and w2 refer to the two force-bearing surfaces of the ejector respectively, and subscript r refers to the ejector connecting rod 13.

[0050] Without considering the flow resistance in the working chamber, that is, the pressure in the working chamber is the same, then:

[0051] F w1 +F w2 =P w1 ·A w1 -P w2 ·A w2 =P w ·(A w1 -A w2 )=P w ·A r

[0052] thereby:

[0053] F=F w1 +F w2 +F b =(P w -P b )·A r =ΔP·A r

[0054] Therefore, for Figure 1 In the heat-driven Stirling device with a given ejector connecting rod 13 area Ar shown, the magnitude of the ejector gas force F depends on the pressure difference ΔP between the working chamber and the buffer chamber 15, and ΔP is limited by the working conditions and performance. Therefore, in order to adjust the frequency over a large range, the existing heat-driven Stirling device needs to significantly adjust the operating temperature of the high-temperature heat exchanger 9, resulting in low operating efficiency.

[0055] Under the same working conditions, that is, when the temperature of the high-temperature heat exchanger 9, the room-temperature heat exchanger temperature (heat pump room-temperature heat exchanger 4 and engine room-temperature heat exchanger 7) and the low-temperature heat exchanger 2 are given, since the pressure difference ΔP between the working chamber and the buffer chamber 15 depends on the above-mentioned related temperatures, therefore, under the given pressure difference ΔP, in order to change the magnitude of the gas force F at both ends of the ejector, the present invention proposes a variable structure of the actual force area of ​​the ejector connecting rod 13, thereby achieving a change in the magnitude of the ejector force by changing the actual force area of ​​the ejector connecting rod 13 under the same working conditions, and ultimately achieving the purpose of adjusting the movement frequency of the ejector.

[0056] Furthermore, the variable structure of the actual force area of ​​the ejector connecting rod 13 includes at least one connecting rod actual force area adjustment cavity 17 formed by the ejector connecting rod 13 and the connecting rod cylinder 16. Figure 3 Various different forms of connecting rod actual force-bearing area adjustment cavities 17 are shown.

[0057] Figure 4 a. Figure 4 b shows a structure composed of two coaxial sections with different diameters d r1 d r2 The ejector connecting rod 13 is composed of a rod, and a connecting rod cylinder 16 matched with the ejector connecting rod 13, the connecting rod cylinder 16 having a diameter d r1 d r2 The two through holes d of the rod h1 d h2 .

[0058] Figure 3 a shows a connecting rod actual force area adjustment cavity 17 formed by the above-mentioned ejector connecting rod 13 and connecting rod cylinder 16, the ejector connecting rod 13 is inserted into the connecting rod cylinder 16, d r1 Rod, d r2 Rod and d h1 d h2 Hole fit, d r1 Rod, d r2 and d h2 The holes form a closed space. Further, a better seal can be achieved between the rod and the corresponding hole through a seal 26, which can be a rubber seal ring, a polytetrafluoroethylene seal ring, etc. The closed space is the actual force area adjustment cavity 17 of the connecting rod.

[0059] Figure 3 b shows another connecting rod actual force area adjustment cavity 17, wherein: the ejector connecting rod 13 is composed of three coaxial sections with two different diameters d r2 d r1 d r2 The connecting rod cylinder 16 has a diameter d r2 1 through hole for rod fitting d h2 , d h2 The hole and the three coaxial rods form a closed space, namely, the actual force-bearing area adjustment cavity 17 of the connecting rod.

[0060] Figure 3 c shows another connecting rod actual force area adjustment cavity 17, which is Figure 3 Based on a, d h1 The hole is a non-through hole, so except for the two d h1 d h2 Hole and two sections d r1 d r2 The rod forms a first closed space, namely, the first connecting rod actual force area adjustment cavity 171, d h1 Hole and D r1 The rod also forms a second closed space, namely, the second connecting rod actual force area adjustment chamber 172.

[0061] Figure 3 d shows another connecting rod actual force area adjustment chamber 17, wherein: the ejector connecting rod 13 is composed of two sections of rods and the two sections of rods are not axially centered, and the connecting rod cylinder 16 has two non-through holes (or blind holes) that match the two sections of rods with different axial centers in the ejector connecting rod 13. Therefore, the two sections of rods with different axial centers and the two non-through holes constitute two connecting rod actual force area adjustment chambers 17, namely, the connecting rod actual force area adjustment chamber 171 and the connecting rod actual force area adjustment chamber 172. The difference from the two sections of coaxial rods having different diameters is that the two sections of rods with different axial centers can have the same diameter or different diameters.

[0062] Figure 3 e shows another connecting rod actual force area adjustment cavity 17, Figure 3 d, one of the holes is a through hole, therefore, the two sections of different axial rods and the two holes only constitute one actual force area adjustment cavity 17 of the connecting rod.

[0063] Figure 3 f shows another connecting rod actual force area adjustment chamber 17, the ejector connecting rod 13 has only one diameter, and the ejector connecting rod 13 and the connecting rod cylinder 16 constitute a connecting rod actual force area adjustment chamber 17. In this case, when the connecting rod actual force area adjustment chamber 17 is connected to the working chamber, there is no force at both ends of the ejector connecting rod 13. In order to drive the ejector connecting rod 13 to reciprocate, for the heat-driven Stirling device of the free piston, it is necessary to configure an electromagnetic drive mechanism 25 for the ejector connected to the ejector connecting rod 13, and drive it by electromagnetic force; for the heat-driven Stirling device with a transmission mechanism 23, it is necessary to set the connection point of the transmission mechanism 23 and the ejector connecting rod 13 between the connecting rod cylinder 16 and the cylinder partition 18, drive the transmission mechanism 23 through other ejector connecting rods, and then drive the ejector connecting rod 13 to reciprocate by the transmission mechanism 23.

[0064] Figure 3 g shows another connecting rod actual force area adjustment cavity 17, Figure 3 Based on a, the ejector connecting rod 13 consists of three coaxial sections with three different diameters d r2 d r1 d r3 The connecting rod cylinder 16 has a diameter d r1 d r2、 d r3 The three through holes d for the rod to fit h1 d h2 and d h3 , forming two connecting rod actual force area adjustment chambers 17, namely connecting rod actual force area adjustment chamber 171 and connecting rod actual force area adjustment chamber 172.

[0065] Furthermore, if Figure 5 As shown, the connecting rod actual force area adjustment chamber 17 has at least one connecting hole 21, and the connecting rod actual force area adjustment chamber 17 is connected with the working chamber and the buffer chamber 15 through the connecting hole 21. It should be pointed out that the connecting rod cylinder 16 can be composed of a connecting rod cylinder 16 body and a cylinder partition 18, or can only include the connecting rod cylinder 16. Accordingly, the connecting hole 21 can be located on the side or end surface of the connecting rod actual force area adjustment chamber 17, or the connecting hole 21 can also be located on the ejector connecting rod 13, which can connect the connecting rod actual force area adjustment chamber 17 with the working chamber and the buffer chamber 15.

[0066] Furthermore, if Figure 6 As shown, the first switch valve 221 and the second switch valve 222 are also included. The first switch valve 221 and the second switch valve 222 can control the connection or disconnection between the actual force-bearing area adjustment chamber 17 of the connecting rod and the working chamber and the buffer chamber 15. During operation, when the actual force-bearing area adjustment chamber 17 of the connecting rod is connected to the working chamber, the actual force-bearing area adjustment chamber 17 of the connecting rod is disconnected from the buffer chamber 15; or when the actual force-bearing area adjustment chamber 17 of the connecting rod is connected to the buffer chamber 15, the actual force-bearing area adjustment chamber 17 of the connecting rod is disconnected from the working chamber.

[0067] by Figure 6 As an example, the variable force area structure of the ejector connecting rod realizes the working principle of the variable force area of ​​the ejector connecting rod, which includes two sections with diameters d r1 With d r2 The ejector connecting rod 13 is composed of a rod, and the connecting rod cylinder 16 cooperates with the ejector connecting rod 13. At this time, the actual force area adjustment cavity 17 of the connecting rod and the working cavity or the buffer cavity are only connected by d h1 Hole-d r1 Rod, d h2 Hole-d r2 Therefore, when the connecting rod actual force area adjustment chamber 17 is connected to the working chamber through the connecting hole 21, the first switch valve 221 and the second switch valve 222, and is disconnected from the buffer chamber, since the pressure in the connecting rod actual force area adjustment chamber 17 is the same as that in the working chamber, the actual force area A of the ejector connecting rod is:

[0068]

[0069] When the connecting rod actual force area adjustment chamber 17 is disconnected from the working chamber and connected to the buffer chamber, since the pressure in the connecting rod actual force area adjustment chamber 17 is the same as that in the buffer chamber, the actual force area A of the ejector connecting rod is:

[0070]

[0071] Preferably, different variable ejector connecting rod actual force areas A can also be realized. Figure 3 The dr1 rod in c and the dh1 hole of the connecting rod cylinder 16 constitute the actual force area adjustment cavity 172 of the second connecting rod. Therefore, it is also composed of two sections with diameter d r1 With d r2 The rod is composed of three different actual force areas of the ejector connecting rod 13. When the second connecting rod actual force area adjustment chamber 172 composed of the dr1 rod and the connecting rod cylinder is in the state of connecting the buffer chamber 15-disconnecting the working chamber, and the first connecting rod actual force area adjustment chamber 171 composed of the dr2 rod and the connecting rod cylinder is in the state of connecting the working chamber-disconnecting the buffer chamber 15, the actual force area A of the ejector connecting rod 13 is:

[0072]

[0073] When the second connecting rod actual force area adjustment chamber 172 composed of the dr1 rod and the connecting rod cylinder 16 is in the state of connecting the buffer chamber-disconnecting the working chamber, and the first connecting rod actual force area adjustment chamber 171 composed of the dr2 rod and the connecting rod cylinder 16 is in the state of connecting the buffer chamber-disconnecting the working chamber, the actual force area A of the ejector connecting rod 13 is:

[0074]

[0075] When the second connecting rod actual force area adjustment chamber 172 composed of the dr1 rod and the connecting rod cylinder 16 is in the state of connecting the working chamber-disconnecting the buffer chamber 15, and the first connecting rod actual force area adjustment chamber 171 composed of the dr2 rod and the connecting rod cylinder 16 is in the state of connecting the buffer chamber 15-disconnecting the working chamber, the actual force area A of the ejector connecting rod 13 is:

[0076]

[0077] Furthermore, in order to realize more different actual force-bearing areas A of the variable displacer connecting rods, the displacer connecting rod 13 can also be composed of connecting rod cylinders 16 having more different diameters and cooperating with the rods of each diameter. Figure 3 g shows a displacer connecting rod 13 composed of three sections with diameter d r1 d r2 d r3 The rod composition and the connecting rod cylinder 16 that cooperates with the ejector connecting rod 13 can constitute the first connecting rod actual force area adjustment chamber 171 and the second connecting rod actual force area adjustment chamber 172. By controlling the connection and disconnection with the buffer chamber 15 or the working chamber, the actual force area A of the ejector connecting rod 13 can be:

[0078]

[0079]

[0080] Preferably, the ejector connecting rod 13 is composed of 2 to 5 sections of rods. r2 Yes r1 1.05 to 3 times of d r2 Yes r1 1.1 to 2 times of.

[0081] Furthermore, in the rod dr1-hole dh1 constituting the actual force area adjustment cavity 17 of the connecting rod, d r1 Rod and matching hole d h1 The difference is between (0 and 2 mm); d r2 Rod and matching hole d h2 The difference is between (0 and 2 mm); more preferably, the difference is between 5 and 500 μm; more preferably, when there is a seal 26 between the rod and the corresponding hole, the difference is above 50 to 500 μm. In addition, it should be pointed out that for example Figure 5 In the case of the cylinder partition plate 18 shown in the figure, the matching hole d h2 It is the size of the hole at the cylinder partition 18, not the diameter d' of the hole at the connecting rod cylinder 16 h2 .

[0082] Furthermore, the difference between the length of the rod dr1, the depth of the hole dh1, the length of the rod dr2, the depth of the hole dh2, and the corresponding ejector stroke is between 0 and 10 cm, wherein Figure 7 The ejector stroke is shown, that is, the ejector connecting rod 13 in d r1 d r2 The length of the rod is greater than or equal to the corresponding ejector stroke.

[0083] Figure 8 A heat-driven Stirling device based on a transmission mechanism is shown, wherein the first ejector connecting rod 131 and the second ejector connecting rod 132 are connected to a transmission mechanism 23, and the transmission mechanism 23 may be a crank-connecting rod transmission mechanism, a diamond transmission mechanism, a Scotch yoke transmission mechanism, etc. In the heat-driven Stirling device based on the transmission mechanism 23, the engine ejector 11 and the heat pump ejector 12 maintain a fixed operating phase.

[0084] Figure 8 What is shown is that the engine ejector 9 and the heat pump ejector 10 both have an ejector connecting rod actual force area variable structure, wherein the ejector connecting rod actual force area variable structure of the engine ejector 9 has a first connecting rod actual force area adjustment cavity 171, and the ejector connecting rod actual force area variable structure of the heat pump ejector 10 has a second connecting rod actual force area adjustment cavity 172.

[0085] Furthermore, the first connecting rod actual force area adjustment chamber 171 is connected through a group of connecting holes 21, a first switch valve 221 and a second switch valve 222 on the upper side, and the connection and disconnection between the connecting rod actual force area adjustment chamber 171 and the working chamber and the buffer chamber 15 can be achieved by controlling the first switch valve 221 and the first switch valve 222. Similarly, the second connecting rod actual force area adjustment chamber 172 is connected through a group of connecting holes 21, a first switch valve 221 and a second switch valve 222 on the lower side, and the connection and disconnection between the second connecting rod actual force area adjustment chamber 172 and the working chamber and the buffer chamber 15 can be achieved.

[0086] Its working process: in the current working state, the first switch valve 221 on the upper side is closed, the second switch valve 222 is opened, and the first switch valve 221 on the lower side is closed, and the second switch valve 222 is opened. When the heat or cold load provided by the device is greater than the required load, the first switch valve 221 on the upper side is closed, the second switch valve 222 is opened, the first switch valve 221 on the lower side is opened, and the second switch valve 224 is closed, so that the actual force area of ​​the second displacer connecting rod 132 is reduced, so that the work done by the second displacer connecting rod 132 is reduced, resulting in a decrease in the operating frequency, and ultimately reducing the heat or cold load provided to the outside; after a period of time, when the heat or cold load provided by the device is lower than the required load, the first switch valve 221 on the upper side is closed, the second switch valve 222 is opened, the first switch valve 221 on the lower side is closed, and the second switch valve 222 is opened, so that the actual force area of ​​the second displacer connecting rod 132 is reduced, so that the work done by the second displacer connecting rod 132 is increased, resulting in an increase in the operating frequency, and ultimately increasing the heat or cold load provided to the outside.

[0087] like Figure 8 As shown in FIG. 2 , the heat-driven Stirling device also includes a control module 27, which is connected to the electromagnetic drive mechanism 25, the first switch valve 221, the second switch valve 222, etc. by signals, and is connected to sensors for detecting relevant pressure or temperature or the rotation speed of the transmission mechanism 23, etc., and automatically controls the opening and closing of relevant switch valves and the control of parameters such as temperature and output load by detecting relevant signals.

[0088] Of course, in other embodiments, one of the engine ejector 9 and the heat pump ejector 10 has a variable structure for the actual force area of ​​the ejector connecting rod. Preferably, the engine ejector connecting rod 131 or the heat pump ejector 132 with a larger diameter has a variable structure for the actual force area of ​​the ejector connecting rod.

[0089] Furthermore, the heat-driven Stirling device further includes an electromagnetic drive mechanism 25, which can be a motor or an electromagnetic force coil. Preferably, the electromagnetic drive mechanism 25 is a motor, in which case the electromagnetic drive mechanism 25 is connected to the rotating shaft in the transmission mechanism 23; or, the electromagnetic drive mechanism 25 is an electromagnetic force coil, which is used to provide an electromagnetic force in the direction of motion of the ejector, thereby driving the ejector to reciprocate linearly.

[0090] Furthermore, when electricity prices are relatively cheap, Figure 8 Taking an example to illustrate how to reduce operating costs, the first switch valve 221 on the upper side is opened and the second switch valve 222 is closed, and the first switch valve 221 on the lower side is opened and the second switch valve 224 is closed. At this time, the actual force area of ​​the first displacer connecting rod 131 and the second displacer connecting rod 132 is at a minimum, and the operating frequency of the first displacer connecting rod 131 and the second displacer connecting rod 132 is reduced. In order to achieve a higher operating frequency, an external power supply is used to drive the motor to provide additional driving force to drive the engine displacer 11 and the heat pump displacer 12 to move, thereby taking advantage of the cheaper electricity price and reducing fuel consumption.

[0091] Embodiment 2

[0092] Fig. 9 Another embodiment of the free piston thermally driven Stirling device of the present invention is shown, including a working chamber, an engine ejector 11, a heat pump ejector 12 and a buffer chamber 15, wherein the working chamber can be a low-temperature chamber 1, a low-temperature heat exchanger 2, a heat pump regenerator 3, a heat pump room temperature heat exchanger 4, a heat pump room temperature chamber 5, an engine room temperature chamber 6, an engine room temperature heat exchanger 7, an engine regenerator 8, a high temperature heat exchanger 9 and a high temperature chamber 10, and the free piston thermally driven Stirling device also includes an ejector connecting rod 13 (the ejector corresponds to the engine ejector 11 and the heat pump ejector 12), and the engine ejector 11 and the heat pump ejector 12 can move freely in a straight line.

[0093] Furthermore, the engine ejector 11 and the heat pump ejector 12 both have a variable structure for the actual force area of ​​the ejector connecting rod. The ejector connecting rod 13 of the engine ejector 11 has a first connecting rod actual force area adjustment chamber 171, and the ejector connecting rod 13 of the heat pump ejector 12 has a second connecting rod actual force area adjustment chamber 172. The first connecting rod actual force area adjustment chamber 171, the second connecting rod actual force area adjustment chamber 172, and the connection and disconnection of the working chamber and the buffer chamber 15 are controlled by two sets of upper and lower switch valves (including a first switch valve 221 and a second switch valve 222).

[0094] When the first connecting rod actual force area adjustment chamber 171 and the second connecting rod actual force area adjustment chamber 172 are simultaneously connected to the buffer chamber 15 and disconnected from the working chamber, the actual force areas of the first displacer connecting rod 131 and the second displacer connecting rod 132 are at their maximum, and the free piston heat-driven Stirling device operates at a higher frequency; when the first connecting rod actual force area adjustment chamber 171 and the second connecting rod actual force area adjustment chamber 172 are simultaneously connected to the working chamber and disconnected from the buffer chamber 15, the actual force areas of the first displacer connecting rod 131 and the second displacer connecting rod 132 are at their minimum, and the free piston heat-driven Stirling device operates at a lower frequency. Therefore, Fig. 9 The free piston heat driven Stirling device shown achieves frequency variation.

[0095] Furthermore, an electromagnetic drive mechanism 25 is included, and the electromagnetic drive mechanism 25 is used to drive the ejector to move linearly. Further, the electromagnetic drive mechanism 25 can be a linear motor or a simple electromagnetic drive mechanism that provides electromagnetic force. The electromagnetic drive mechanism 25 can be located in the working chamber or the spring chamber 15, or outside the working chamber, to provide a linear electromagnetic pulling force.

[0096] Embodiment 3

[0097] Fig.10 A heat-driven Stirling device capable of adjusting working pressure is shown, which further comprises a working fluid storage tank 24 on the basis of one embodiment. When the heat or cold load provided by the device is greater than the required load, the heat or cold load provided by the device is reduced by reducing the average pressure in the working chamber, wherein the process of reducing the average pressure in the working chamber is completed by the working pressure regulating chamber 24, the connecting rod actual force area regulating chamber 17 and two sets of switch valves. When the working pressure of the heat-driven Stirling device is high and the output load exceeds the required load, the actual force area regulating chamber 17 of the connecting rod plays a compression role, and at least one valve of the first switch valve 221 or the second switch valve 222 is equivalent to an intake valve. When the pressure in the actual force area regulating chamber 17 of the connecting rod is higher than the working fluid storage tank 24, the actual force area regulating chamber 17 of the connecting rod is connected with the working fluid storage tank 24, and part of the working fluid is compressed into the working chamber pressure regulating chamber 24, thereby reducing the working pressure in the working chamber; similarly, when the working pressure needs to be increased, in the process of the pressure in the actual force area regulating chamber 17 of the connecting rod being lower than the working fluid storage tank 24, the actual force area regulating chamber 17 of the connecting rod is connected with the working fluid storage tank 24, and part of the working fluid is released from the working chamber pressure regulating chamber 24 to the working chamber or the buffer chamber, thereby increasing the working pressure in the working chamber.

[0098] Further, when the cold end piston moves toward the direction in which the volume of the connecting rod actual force area adjustment chamber 17 increases ( Fig.10The first switch valve 221 or the second switch valve 222 is opened, the third switch valve 223 and the fourth switch valve 224 are closed, the volume of the connecting rod actual force area adjustment chamber 17 increases, and the working fluid in the working chamber or the buffer chamber 15 flows into the connecting rod actual force area adjustment chamber 17; when the cold end piston is upward, the first switch valve 221 and the second switch valve 222 are closed, the third switch valve 223 is closed, and the working fluid in the connecting rod actual force area adjustment chamber 17 is compressed. When the working fluid pressure in the connecting rod actual force area adjustment chamber 17 reaches a certain value, value, the third switch valve 223 opens, and the working fluid flows from the connecting rod actual force area adjustment chamber 17 into the working fluid storage tank 24. Therefore, the total working fluid in the working chamber and the buffer chamber 15 is reduced, thereby reducing the average pressure in the working chamber; when the heat or cold load provided by the device is less than the required load, the third switch valve 223 opens, and the working fluid flows from the working fluid storage tank 24 into the connecting rod actual force area adjustment chamber 17. By opening the first switch valve 221 or the second switch valve 222, the working fluid released from the working fluid storage tank 24 can flow into the working chamber or the buffer chamber 15.

[0099] Furthermore, the working fluid storage tank 24 has an intake valve 241 and an exhaust valve 242. The intake valve 241 is used to control the opening pressure of the working fluid flowing from the actual force area adjustment chamber 17 of the connecting rod into the working fluid storage tank 24, and the exhaust valve 242 is used to control the opening pressure of the working fluid flowing from the working fluid storage tank 24 into the actual force area adjustment chamber 17 of the connecting rod. Preferably, the intake valve 241 and the exhaust valve 242 are one-way valves. In this case, the working process is as follows:

[0100] When the heat or cold load provided by the device is greater than the required load, the heat or cold load provided by the device is reduced by reducing the average pressure in the working chamber. When the cold end piston is downward, the first switch valve 221 or the second switch valve 222 is opened, the third switch valve 223 and the fourth switch valve 224 are closed, the volume of the connecting rod actual force area adjustment chamber 17 increases, and the working fluid in the working chamber or the buffer chamber 15 flows into the connecting rod actual force area adjustment chamber 17; when the cold end piston is upward, the first switch valve 221 and the second switch valve 222 are closed, the third switch valve 223 is opened, the working fluid in the connecting rod actual force area adjustment chamber 17 is compressed, and the connecting rod actual force area adjustment chamber 17 is compressed. When the working fluid pressure in the area regulating chamber 17 reaches a certain value, the working fluid flows from the connecting rod actual force area regulating chamber 17 through the intake valve 241 into the working fluid storage tank 24. Therefore, the total working fluid in the working chamber and the buffer chamber 15 is reduced, thereby reducing the average pressure in the working chamber; when the heat or cold load provided by the device is less than the required load, the third switch valve 223 is closed and the fourth switch valve 224 is opened, and the working fluid flows from the working fluid storage tank 24 through the exhaust valve 242 into the connecting rod actual force area regulating chamber 17. By opening the first switch valve 221 or the second switch valve 222, the working fluid released from the working fluid storage tank 24 can flow into the working chamber or the buffer chamber 15.

[0101] The operating pressure of the regulating device can act together with the regulating frequency to reduce the regulating range and frequency of the frequency.

[0102] Example 4

[0103] Fig.11 Disclosed is an operating method of the above-mentioned thermally-driven Stirling device. By controlling the connection and disconnection of the buffer chamber 15 or the working chamber and the connecting rod actual force area adjusting chamber 17, the movement frequency of the thermally-driven Stirling device can be adjusted, thereby adjusting the thermal load of the thermally-driven Stirling device.

[0104] Specifically, taking Fig.10 as an example, the second ejector connecting rod 132 of the heat pump ejector 12 is composed of two coaxial rods with different diameters (d r1 , d r2 , where d r2 >d r1 ). In order to achieve a high movement frequency f2 within a certain time, control the connecting rod actual force area adjusting chamber 17 to communicate with the buffer chamber 15 and disconnect from the working chamber; in order to achieve a low movement frequency f1 (f1 < f2) within a certain time, control the connecting rod actual force area adjusting chamber 17 to communicate with the working chamber and disconnect from the buffer chamber 15. Thus, the operation modes of high movement frequency f2 and low movement frequency f1 can be achieved, enabling the device to have two-stage frequency adjustment, as shown in the following table:

[0105] Working chamber Buffer cavity frequency model Connecting rod actual force area adjustment cavity 17 disconnect Connectivity f2 high frequency Connecting rod actual force area adjustment cavity 17 Connectivity disconnect f1 Low Frequency

[0106] Furthermore, in order to increase the movement frequency adjustment range, the number of rods with different diameters and the number of holes can be increased, as shown in Figure 3 g. When an ultra-high movement frequency f3 is required, control the first connecting rod actual force area adjusting chamber 171 and the second connecting rod actual force area adjusting chamber 172 to communicate with the buffer chamber 15 and disconnect from the working chamber; when a high movement frequency f2 is required, control the second connecting rod actual force area adjusting chamber 172 to communicate with the buffer chamber 15 and disconnect from the working chamber, and control the first connecting rod actual force area adjusting chamber 171 to communicate with the working chamber and disconnect from the buffer chamber 15, or control the second connecting rod actual force area adjusting chamber 172 to communicate with the working chamber and disconnect from the buffer chamber 15, and control the first connecting rod actual force area adjusting chamber 171 to communicate with the buffer chamber 15 and disconnect from the working chamber; when a low movement frequency f1 is required, control the first connecting rod actual force area adjusting chamber 171 and the second connecting rod actual force area adjusting chamber 172 to communicate with the working chamber and disconnect from the buffer chamber 15.

[0107] Example 5

[0108] Fig.11 and 12The operation method of the above heat-driven Stirling device is shown, which can realize stepless load control. The stepless load control method is based on selecting different actual force-bearing areas of the connecting rod to realize that the device has ≥2 natural operating frequencies. The stepless load control method can be any of the following:

[0109] (1) Detect the difference between the set temperature and the actual temperature, calculate the required operating frequency fR based on the temperature deviation, and then calculate the operating time t1 and t2 based on the operating frequencies f1 and f2 of the device. The device runs at the frequency f1 for t1 time and at the frequency f2 for t2 time (multiple cycles can be performed if necessary). By controlling the time t1 and t2, the output load of the device within the time t1+t2 is equal to the required load.

[0110]

[0111] Where: t1 and t2 are the operating time at operating frequencies f1 and f2 respectively, and Q1 and Q2 are the load outputs at operating frequencies f1 and f2 respectively.

[0112] Furthermore, the maximum movement frequency f2 of the thermally driven Stirling device (the hot end temperature is 700°C, and the warm end and the cold end are at rated operating conditions) is ≥15Hz, and the minimum movement frequency f1 of the thermally driven Stirling device (the hot end temperature is 500°C, and the warm end and the cold end are at rated operating conditions) is ≤10Hz.

[0113] Furthermore, the operation time of t1 and t2 is not less than the time required for the heat-driven Stirling device to operate one cycle. Preferably, 0.1s≤t1≤1h, 0.1s≤t2≤1h.

[0114] (2) According to the demand load, the natural operating frequency fi that is closest to the demand load is selected from the available operating frequencies of the device (such as f1 and f2 mentioned above). The difference between the natural operating frequency fi and the demand operating frequency fR corresponding to the demand load is supplemented by the electromagnetic drive mechanism 25, thereby achieving a balance between the load provided by the device and the demand load.

[0115] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A heat-driven Stirling device, comprising a working chamber, an engine ejector (11), a heat pump ejector (12) and a buffer chamber (15), wherein the working chamber is a low-temperature chamber (1), a low-temperature heat exchanger (2), a heat pump regenerator (3), a heat pump room-temperature heat exchanger (4), a heat pump room-temperature chamber (5), an engine room-temperature chamber (6), an engine room-temperature heat exchanger (7), an engine regenerator (8), a high-temperature heat exchanger (9) and a high-temperature chamber (10), wherein the engine ejector (11) and the heat pump ejector (12) are provided with ejector connecting rods (13), and the ejector connecting rods (13) extend into the buffer chamber (15), and wherein: A connecting rod cylinder (16) is provided on the outer periphery of a portion of at least one of the ejector connecting rods (13) located in the buffer chamber (15); a sealed connecting rod actual force area adjustment chamber (17) is formed between the connecting rod cylinder (16) and the ejector connecting rod (13); a first switch valve (221) is provided between the connecting rod actual force area adjustment chamber (17) and the corresponding working chamber; a second switch valve (222) is provided between the buffer chamber (15) and the connecting rod actual force area adjustment chamber (17); the thermally driven Stirling device further comprises a control module (27) and an electromagnetic drive mechanism (25) for driving the ejector to move; the control module (27) is signal-connected to the electromagnetic drive mechanism (25), the first switch valve (221), and the second switch valve (222); When operating in the low-frequency mode, the connecting rod actual force area adjustment chamber (17) is disconnected from the buffer chamber (15) and connected to the corresponding working chamber; When the high-frequency mode is in operation, the connecting rod actual force area adjustment chamber (17) is connected to the buffer chamber (15) and disconnected from the corresponding working chamber; The device operates at the low frequency mode f1 for a time of t1 and at the high frequency mode f2 for a time of t2. By controlling the length of the time t1 and t2, the output load of the device during the time t1+t2 is equal to the demand load; Or, first calculate the required operating frequency f R , and then select the operating frequency f closest to the required operating frequency from the available operating frequencies R The natural operating frequency fi, the required operating frequency f R The difference between the natural operating frequency fi is supplemented by the electromagnetic drive mechanism (25), so that the device operating frequency is f R .

2. The heat-driven Stirling device according to claim 1, characterized in that: The ejector connecting rod (13) comprises at least two coaxial rod sections and the diameters of two adjacent rod sections are different, or the ejector connecting rod (13) comprises at least two rod sections with different axes; the connecting rod cylinder (16) comprises at least two inner holes and is arranged one-to-one with each rod section.

3. The heat-driven Stirling device according to claim 2, characterized in that: The difference between the length of each rod segment and the corresponding ejector stroke is 0 to 10 cm, the difference between the length of each inner hole and the corresponding ejector stroke is 0 to 10 cm, and the difference between the diameter of each rod segment and the diameter of the corresponding inner hole is 0 to 2 mm.

4. The heat-driven Stirling device according to any one of claims 1 to 3, characterized in that: The engine ejector (11) and the heat pump ejector (12) are both provided with ejector connecting rods (13), and a transmission mechanism (23) is provided between the two ejector connecting rods (13).

5. The heat-driven Stirling device according to claim 4, characterized in that: The two ejector connecting rods (13) have different diameters, and the connecting rod cylinder (16) is arranged on the outer periphery of the ejector connecting rod (13) with a larger diameter.

6. The heat-driven Stirling device according to any one of claims 1 to 3, characterized in that: It also includes a working fluid storage tank (24), and a third switch valve (223) is provided between the working fluid storage tank (24) and the connecting rod actual force area adjustment chamber (17).

7. The heat-driven Stirling device according to claim 6, characterized in that: A fourth switch valve (224) is further provided between the working fluid storage tank (24) and the connecting rod actual force area adjustment chamber (17), an intake valve (241) is provided between the third switch valve (223) and the working fluid storage tank (24), and an exhaust valve (242) is provided between the fourth switch valve (224) and the working fluid storage tank (24).

8. A method for operating a heat-driven Stirling device as claimed in claim 6, characterized in that: The invention comprises working pressure regulation: when the working pressure is high and the output load exceeds the required load, during the process of reducing the volume of the connecting rod actual force-bearing area regulating chamber (17), the first switch valve (221) and the second switch valve (222) are closed; when the pressure of the connecting rod actual force-bearing area regulating chamber (17) is higher than that of the working fluid storage tank (24), the third switch valve (223) is opened, and the working fluid storage tank (24) is connected to the connecting rod actual force-bearing area regulating chamber (17); during the process of increasing the volume of the connecting rod actual force-bearing area regulating chamber (17), the first switch valve (221) or the second switch valve (222) is opened, the third switch valve (223) is closed, and the working fluid storage tank (24) is disconnected from the connecting rod actual force-bearing area regulating chamber (17).

9. A method for operating a heat-driven Stirling device as claimed in claim 7, characterized in that: The invention comprises working pressure regulation: when the working pressure is high and the output load exceeds the required load, during the process of reducing the volume of the connecting rod actual force-bearing area regulating chamber (17), the first switch valve (221) and the second switch valve (222) are closed; when the pressure of the connecting rod actual force-bearing area regulating chamber (17) is higher than that of the working fluid storage tank (24), the third switch valve (223) is opened, and the working fluid storage tank (24) is connected to the connecting rod actual force-bearing area regulating chamber (17); during the process of increasing the volume of the connecting rod actual force-bearing area regulating chamber (17), the first switch valve (221) or the second switch valve (222) is opened, the third switch valve (223) is closed, and the working fluid storage tank (24) is disconnected from the connecting rod actual force-bearing area regulating chamber (17).

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