A Stirling generator heating system

Abstract

A Stirling generator heating system includes a biomass gas combustion section and a Stirling generator heat exchange section. The biomass gas combustion section includes a biomass gas pipeline, a gas premixing chamber, a blower, a mixed gas pipeline, a combustion chamber, an igniter, and a flue gas pipeline. The biomass gas pipeline and the blower are respectively connected to the gas premixing chamber, which is connected to the combustion chamber via the mixed gas pipeline. The combustion chamber is provided with an igniter. The Stirling generator heat exchange section includes a pressure shell, a heater, an external heat absorber, a regenerator, and a heat radiation baffle. The pressure shell is disposed within the combustion chamber, the cylinder is disposed within the pressure shell, the heater and regenerator are disposed between the cylinder and the pressure shell, the heater and regenerator are located within the pressure shell, the external heat absorber and the heat radiation baffle are located on the outer wall of the pressure shell, the external heat absorber is located in the heater section, and the heat radiation baffle is located in the regenerator section. The present invention can enhance the heat exchange capacity of the hot end of the Stirling generator and reduce processing costs.

Description

Technical Field

[0001] The present invention relates to a Stirling generator, in particular to a Stirling generator heating system. Background Art

[0002] A Stirling generator is a closed-cycle external combustion generator primarily composed of a heat exchange system, a resonance system, and a power generation system. The heat exchange system creates a large temperature difference between the two ends of the working chamber. The reciprocating motion of the valve piston within the working chamber causes the high-pressure working fluid to be circulated and heated between the hot and cold ends, creating a pressure wave. This pressure wave acts on the power piston, driving the generator system to generate electricity. A Stirling generator completes a Stirling cycle through four processes: isothermal compression, isochoric heating, isothermal expansion, and isochoric cooling.

[0003] Currently, common Stirling generators are mainly of the crank-connecting rod type and the free-piston type. Crank-connecting rod Stirling generators have a shorter continuous operating life due to lateral piston forces and dynamic sealing issues. Free-piston Stirling generators are more compact and do not have dynamic sealing issues, resulting in higher operational reliability, longer lifespan, and lower noise. They have great application potential in extreme environment power generation, underwater power, industrial waste heat power generation, and household cogeneration. Free-piston Stirling generators primarily consist of key components such as a heater, regenerator, cooler, piston, and leaf springs. The heater absorbs heat from an external heat source to heat the working fluid, significantly affecting the output power of the Stirling generator.

[0004] Stirling generators are highly versatile and can generate electricity using fuels such as coal, diesel, natural gas, and biomass. Due to the significant renewable advantage of biomass, using biomass for Stirling power generation has positive implications for environmental protection, replacing fossil fuels, and contributing to the "dual carbon goals." However, the low calorific value of biomass gas requires the Stirling generator heater to have a stronger heat exchange capacity to ensure sufficient power generation. The high cost of Stirling generators has limited the widespread application of biomass Stirling power generation in areas such as factory and household combined heat and power generation.

[0005] The heater is a key component of a free-piston Stirling generator. This component absorbs heat from an external heat source to heat the working fluid, significantly affecting the generator's output power. Heaters generally employ curved tube or fin-type structures. Compared to curved tube heaters, fin-type heaters are more compact, have a smaller dead volume, and minimize power loss, but exhibit poor heat transfer capabilities. Conventional heaters and Stirling generator casings are constructed from different materials, and the two components are typically welded using vacuum brazing, which results in high processing costs. Vacuum brazing also requires a gap of 50-100 μm between the two welded components, placing high demands on component processing precision. Consequently, heater processing costs are high. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a Stirling generator heating system, which can enhance the heat exchange capacity of the hot end of the Stirling generator, reduce the processing cost of the Stirling generator, and has excellent application value.

[0007] The technical solution adopted by the present invention to solve its technical problem is a Stirling generator heating system, including a biomass gas combustion part and a Stirling generator heat exchange part, the biomass gas combustion part includes a biomass gas pipeline, a gas premixing chamber, a blower, a mixed gas pipeline, a combustion chamber, an igniter and a flue gas pipeline, the biomass gas pipeline and the blower are respectively connected to the gas premixing chamber, the gas premixing chamber is connected to the combustion chamber through the mixed gas pipeline, the combustion chamber is provided with an igniter, and the flue gas pipeline is provided on the combustion chamber; the Stirling generator heat exchange part includes a pressure shell , heater, external heat absorber, regenerator and heat radiation baffle, the pressure shell is arranged in the combustion chamber, the cylinder is arranged in the pressure shell, the heater and regenerator are arranged between the cylinder and the pressure shell, the heater and regenerator are located in the pressure shell, the regenerator is installed below the heater, the section of the pressure shell where the heater is assembled is the heater section, and the section of the pressure shell where the regenerator is assembled is the regenerator section; the external heat absorber and heat radiation baffle are located on the outer wall of the pressure shell, the external heat absorber is located in the heater section, the heat radiation baffle is located in the regenerator section, and the gas piston is located in the cylinder.

[0008] Furthermore, the heater is a hollow annular structure, and the inner wall of the heater is divided into two parts, the upper part is an annular arc surface parallel to the top arc surface of the valve piston. When the valve piston moves to the top dead center, the annular arc surface of the upper part of the inner wall of the heater fits with the top arc surface of the valve piston; the lower part is an annular vertical surface parallel to the side of the cylinder, and has a clearance fit with the side of the cylinder; the outer wall of the heater is divided into two parts, the upper part is an arc surface parallel to the top arc surface of the pressure shell, and fits tightly with the top arc surface of the pressure shell, and the lower part is a vertical surface parallel to the side of the pressure shell, and fits tightly with the side of the pressure shell.

[0009] Furthermore, the heater adopts a fin-type structure, and the heater is surrounded by multiple heating fins. The inner wall of the heater is the heating fin surface, and the upper part of the outer wall of the heater is the heating fin surface. The heating fin surface of the upper part of the outer wall of the heater fits tightly with the pressure shell, and the heating fin surface of the inner wall of the heater is a clearance fit with the cylinder.

[0010] Furthermore, the external heat absorber adopts a fin-type structure, the external heat absorber is a hollow annular structure, the heat absorption fins of the external heat absorber are arranged on the outer wall of the external heat absorber, and the inner wall of the external heat absorber is welded to the outer wall of the pressure shell into one.

[0011] Furthermore, the wall thickness of the heater section of the pressure shell is thinner than that of other parts.

[0012] Furthermore, the heater and the pressure shell are hydraulically interference fit.

[0013] Furthermore, the combustion chamber is a sandwich structure, and an insulating layer is formed between the inner and outer layers of the sandwich.

[0014] Compared with the prior art, the advantages of the present invention are as follows:

[0015] The Stirling generator heating system of the present invention can enhance the heat exchange capacity of the hot end of the Stirling generator, reduce the processing cost of the Stirling generator, and has excellent application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural cross-sectional view of an embodiment of the present invention.

[0017] Figure 2 yes Figure 1 A cross-sectional view of the structure of the pressure shell of the illustrated embodiment.

[0018] Figure 3 yes Figure 1 A cross-sectional view of the structure of the heater of the illustrated embodiment.

[0019] Figure 4 yes Figure 1 A cross-sectional view of the structure of the external heat sink of the illustrated embodiment.

[0020] In the figure, 1 is the biomass gas pipeline, 2 is the gas premixing chamber, 3 is the blower, 4 is the mixed gas pipeline, 5 is the combustion chamber, 6 is the insulation layer, 7 is the igniter, 8 is the flange, 9 is the linear motor, 10 is the pressure shell, 11 is the heater, 12 is the external heat absorber, 13 is the gas distribution piston, 14 is the cylinder, 15 is the regenerator, 16 is the heat radiation baffle, and 17 is the flue gas pipeline. DETAILED DESCRIPTION

[0021] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0022] Reference Figure 1 The Stirling generator heating system of the present invention includes a biomass gas combustion part and a Stirling generator heat exchange part. The biomass gas combustion part includes a biomass gas pipeline 1, a gas premixing chamber 2, a blower 3, a mixed gas pipeline 4, a combustion chamber 5, an igniter 7 and a flue gas pipeline 17. The biomass gas pipeline 1 and the blower 3 are respectively connected to the gas premixing chamber 2, the gas premixing chamber 2 is connected to the combustion chamber 5 through the mixed gas pipeline 4, an igniter 7 is provided in the combustion chamber 5, the combustion chamber 5 is a sandwich structure, and an insulating layer 6 is formed between the inner and outer layers of the sandwich. The flue gas pipeline 17 is provided on the combustion chamber 5.

[0023] The heat exchange section of the Stirling generator includes a pressure shell 10, a heater 11, an external heat absorber 12, a regenerator 15, and a heat radiation baffle 16. The pressure shell 10 is located within the combustion chamber 5, and the cylinder 14 is located within the pressure shell 10. The heater 11 and regenerator 15 are located between the cylinder 14 and the pressure shell 10. The heater 11 and regenerator 15 are located within the pressure shell 10, and the regenerator 15 is installed below the heater 11. The section of the pressure shell 10 where the heater 11 is mounted is the heater section, and the section where the regenerator 15 is mounted is the regenerator section. The external heat absorber 12 and heat radiation baffle 16 are located on the outer wall of the pressure shell 10. The external heat absorber 12 is located in the heater section, and the heat radiation baffle 16 is located in the regenerator section. The external heat absorber 12, pressure shell 10, heater 11, and regenerator 15 are all coaxially assembled. The gas distribution piston 13 is arranged in the cylinder 14, and the linear motor 9 is installed on the bottom of the pressure shell 10 through the flange 8. The linear motor 9 is connected to the gas distribution piston 13, and the pressure shell 10 is provided with high-pressure working medium gas.

[0024] The pressure shell 10 is made of stainless steel, and the top of the pressure shell 10 is arc-shaped, which has strong high temperature and high pressure resistance. Figure 2 The wall thickness of the pressure shell 10 is differentiated by design. The heater section of the pressure shell 10 is thinner than other sections, resulting in a stronger heat exchange capacity. The pressure in this section is shared by the outer wall of the pressure shell 10 and the external heat absorber 12, ensuring both heat exchange and pressure bearing capacity. The effect of the heater 11 on Stirling performance is primarily reflected in heat exchange and dead volume (the volume not swept by the valve piston). The stronger the heat exchange capacity of the heater 11, the more heat it can transfer to the gas working fluid for expansion and work. The smaller the dead volume, the greater the pressure differential gas wave can generate while maintaining the stroke of the valve piston 13, thus enhancing the work capacity of the power piston. In terms of enhanced heat exchange, the material of the heater 11 is copper, which has a strong heat exchange capacity. Copper is softer than stainless steel, so the outer diameter of the heater 11 is slightly larger than the inner diameter of the pressure shell 10. It is pressed into the top of the pressure shell 10 using a hydraulic press. During operation, the heater 11 expands due to heat, and fits more closely with the pressure shell 10, thereby enhancing the heat exchange capacity. This hydraulic interference fit is more economical than traditional brazing, and the heater 11 has a higher heat resistance, which can reach above 600°C, exceeding the melting temperature of brazing.

[0025] Reference Figure 3The heater 11 is a hollow annular structure. The inner wall of the heater 11 is divided into two parts, the upper part is an annular arc surface parallel to the top arc surface of the gas piston 13. When the gas piston 13 moves to the top dead center (the top dead center refers to the highest point of the stroke of the gas piston 13), the annular arc surface of the upper part of the inner wall of the heater 11 fits with the top arc surface of the gas piston 13; the lower part is an annular vertical surface parallel to the side of the cylinder 14, and has a clearance fit with the side of the cylinder 14; the outer wall of the heater 11 is divided into two parts, the upper part is an arc surface parallel to the top arc surface of the pressure shell 10, and fits tightly with the top arc surface of the pressure shell 10, and the lower part is a vertical surface parallel to the side of the pressure shell 10, and fits tightly with the side of the pressure shell 10.

[0026] The heater 11 adopts a fin-type structure, which is more compact than the elbow-type heater. The heater 11 is surrounded by 180 heating fins. The thinnest part of the heating fin is 0.56mm, and the thickest part of the heating fin is 0.68mm. This allows the heating fins and the working medium to have a large heat exchange area and strong heat exchange capacity. The inner wall of the heater 11 is the heating fin surface, and the upper part of the outer wall of the heater 11 is the heating fin surface. The heating fin surface of the upper part of the outer wall of the heater 11 fits tightly with the pressure shell 10, increasing the contact area between the heating fins and the pressure shell 10 and enhancing the heat exchange at the top of the pressure shell 10. The heating fin surface of the inner wall of the heater 11 is in a clearance fit with the cylinder 14, ensuring that the heating fins have a large contact area with the working medium and avoiding direct contact between the heating fins and the cylinder 14, which causes heat to be lost by heat conduction. In terms of reducing the useless volume, the upper part of the inner wall of the heater is parallel to the top arc surface of the gas distribution piston 13. When the gas distribution piston 13 moves to the top dead center (the top dead center refers to the highest point of the stroke of the gas distribution piston 13), the annular arc surface of the upper part of the inner wall of the heater fits with the top arc surface of the gas distribution piston 13, reducing the cavity between the heating fins and the gas distribution piston 13, which can produce a smaller useless volume when the gas distribution piston 13 moves, thereby reducing power loss.

[0027] Reference Figure 4 The external heat absorber 12 is made of stainless steel and has a finned structure. It is a hollow, ring-shaped structure with heat-absorbing fins located on its outer wall. The inner wall of the external heat absorber 12 is welded to the outer wall of the pressure shell 10. A K-type armored thermocouple is installed in the external heat absorber 12, which cooperates with a temperature control device to ensure that the heating temperature reaches the rated value.

[0028] The regenerator 15 is an energy storage component made of sintered stainless steel wire mesh. Before the working medium flows into the heater 11, it will be preheated by the regenerator 15 to increase its temperature, thereby reducing the heat demand of the heater 11. The gas piston 13 is responsible for configuring the internal gas working medium; the cylinder 14 can isolate the heater 11 from the gas piston 13 to form a gas channel. During installation, the gap between the cylinder 14 and the gas piston 13 is at most 0.1mm. The linear motor 9 converts mechanical energy into electrical energy. The heat radiation baffle 16 can absorb the radiant heat of the combustion chamber 5 and the heat conducted from the outer wall of the pressure shell 10, reducing the cooler of the Stirling generator ( Figure 1 The heat dissipation burden of the cooler is not shown), which makes the cooler temperature lower and the Stirling machine more efficient. The material is aluminum alloy, and the outer wall of the pressure shell 10 is hydraulically interfered with, which makes assembly simpler.

[0029] When the Stirling generator heating system is working, the biomass gas is transported to the gas premixing chamber 2 through the biomass gas pipeline 1. At the same time, the blower 3 sends air into the gas premixing chamber 2 to fully mix with the biomass gas. The mixed gas is transported to the combustion chamber 5 through the mixed gas pipeline 4. The igniter 7 in the combustion chamber 5 ignites and burns the mixed gas, heating the external heat absorber 12. After the mixed gas is fully burned, the flue gas is discharged through the flue gas pipeline 17.

[0030] In the combustion chamber 5 , the external heat absorber 12 is heated by the flame, and the external heat absorber 12 obtains heat, and the heat is conducted to the heater 11 through the pressure shell 10 , and is heat-exchanged to the internal gas working medium through the heating fins.

[0031] When the gas distribution piston 13 moves to the cold cavity ( Figure 1 When the working medium in the cold chamber is squeezed and flows out of the cold end, it passes through the regenerator 15 for preheating, and then passes through the heater 11 for final heating, and then in the hot chamber ( Figure 1 The expansion (not shown) does work, converting thermal energy into mechanical energy.

[0032] Those skilled in the art may make various modifications and variations to the present invention. If these modifications and variations are within the scope of the claims of the present invention and their equivalents, then these modifications and variations are also within the scope of protection of the present invention.

[0033] The contents not described in detail in the specification are prior art known to those skilled in the art.

Claims

1. A Stirling generator heating system, comprising a biomass gas combustion part and a Stirling generator heat exchange part, characterized in that: The biomass gas combustion part includes a biomass gas pipeline, a gas premixing chamber, a blower, a mixed gas pipeline, a combustion chamber, an igniter and a flue gas pipeline. The biomass gas pipeline and the blower are respectively connected to the gas premixing chamber, the gas premixing chamber is connected to the combustion chamber through the mixed gas pipeline, an igniter is provided in the combustion chamber, and the flue gas pipeline is provided on the combustion chamber; the heat exchange part of the Stirling generator includes a pressure shell, a heater, an external heat absorber, a regenerator and a heat radiation baffle, the pressure shell is provided in the combustion chamber, the cylinder is provided in the pressure shell, the heater and the regenerator are provided between the cylinder and the pressure shell, the heater and the regenerator are located in the pressure shell, the regenerator is installed below the heater, the section of the pressure shell where the heater is assembled is the heater section, and the section of the pressure shell where the regenerator is assembled is the regenerator section. ; The external heat absorber and the heat radiation baffle are located on the outer wall of the pressure shell, the external heat absorber is located in the heater section, the heat radiation baffle is located in the regenerator section, and the gas piston is arranged in the cylinder; the heater is a hollow annular structure, and the inner wall of the heater is divided into two parts, the upper part is an annular arc surface parallel to the top arc surface of the gas piston, when the gas piston moves to the top dead center, the annular arc surface of the upper part of the inner wall of the heater fits with the top arc surface of the gas piston; the lower part is an annular vertical surface parallel to the side of the cylinder, and has a gap with the side of the cylinder; the outer wall of the heater is divided into two parts, the upper part is an arc surface parallel to the top arc surface of the pressure shell, and fits tightly with the top arc surface of the pressure shell, and the lower part is a vertical surface parallel to the side of the pressure shell, and fits tightly with the side of the pressure shell.

2. The Stirling generator heating system according to claim 1, wherein: The heater adopts a fin-type structure, and the heater is surrounded by multiple heating fins. The inner wall of the heater is the heating fin surface, and the upper part of the outer wall of the heater is the heating fin surface. The heating fin surface of the upper part of the outer wall of the heater fits tightly with the pressure shell, and the heating fin surface of the inner wall of the heater is loosely matched with the cylinder.

3. The Stirling generator heating system according to claim 1, wherein: The external heat absorber adopts a fin-type structure and is a hollow annular structure. The heat absorbing fins of the external heat absorber are arranged on the outer wall of the external heat absorber, and the inner wall of the external heat absorber is welded to the outer wall of the pressure shell into one.

4. The Stirling generator heating system according to claim 1, wherein: The wall thickness of the heater section of the pressure shell is thinner than that of other parts.

5. The Stirling generator heating system according to claim 1, wherein: The heater and the pressure shell are hydraulically interference fit.

6. The Stirling generator heating system according to claim 1, wherein: The combustion chamber is a sandwich structure, and a heat insulating layer is formed between the inner and outer layers of the sandwich.

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