TW202221227A - Thermal energy conversion system and method for controlling a working fluid thereof - Google Patents

Abstract

A thermal energy conversion system is provided to solve the problem of kinetic energy loss of the conventional thermal energy conversion system adjusting the circulation flow and the rotating speed of the generator. The system comprises a starter generator with a drive shaft, two permanent magnet drivers respectively connected to the two ends of the drive shaft, an expander, a compressor, an evaporator, and a condenser. Each permanent magnet driver comprises an air gap with adjustable size. The expander and the compressor are respectively connected to the two permanent magnet drivers. The expander converts the internal energy of a working fluid with gaseous state into rotational kinetic energy. The compressor converts the rotational kinetic energy into kinetic energy of the liquid working fluid. The evaporator receives the liquid working fluid from the compressor and evaporates the working fluid, then imports the gaseous working fluid into the expander. The condenser receives the gaseous working fluid from the expander and condenses the working fluid, then imports the liquid working fluid into the compressor. A method for controlling the working fluid of the thermal energy conversion system is also provided.

Description

Thermoelectric power generation system and its working fluid flow control method

The invention relates to a regenerative energy power generation technology, in particular to a thermoelectric power generation system that improves energy conversion efficiency and is suitable for low-temperature waste heat and a method for regulating the flow of working medium.

The thermoelectric power generation system uses the principle of heat exchange. The working fluid with a low boiling point (Working Fluid) is evaporated into a gaseous state by the heat source, and the expansion pressure of the gaseous working fluid is used to drive the turbine to generate electricity. Repeating the cycle of expansion and compression of the working fluid continues to generate electricity.

The conventional thermoelectric power generation technology utilizes stable and large-scale cold and heat sources, such as deep low-temperature seawater and surface normal-temperature seawater, which can provide a temperature difference that does not change with season or time, so that the generator can output stable power and convert energy. Efficiency can be economical. However, when the heat source of thermoelectric power generation is discontinuous heat energy, such as industrial waste heat, geothermal heat or biomass heat, etc., in order to maintain stable power generation, a pump and a throttle valve must be added to the circulation pipeline to adjust the flow of the working medium, or The use of frequency converters to control the speed of generators will cause the thermoelectric power generation system to consume extra power, reducing the overall energy conversion efficiency, which is not conducive to the promotion and application of low-temperature waste heat reuse technology.

In view of this, it is still necessary to improve the conventional thermoelectric power generation system.

In order to solve the above problems, the purpose of the present invention is to provide a thermoelectric power generation system, which can make full use of rotational kinetic energy and reduce extra energy consumption.

Another object of the present invention is to provide a thermoelectric power generation system that can adjust the transmission torque between the devices.

Another object of the present invention is to provide a working medium flow control method for a thermoelectric power generation system, which can control the fluid circulation and stabilize the power generation.

Another object of the present invention is to provide a working medium flow control method for a thermoelectric power generation system, which can be applied to a low-temperature waste heat environment with discontinuous heat sources.

The use of the quantifier "a" or "an" for the elements and components described throughout the present invention is only for convenience and provides a general meaning of the scope of the present invention; in the present invention, it should be construed as including one or at least one, and a single The concept of also includes the plural case unless it is obvious that it means otherwise.

The thermoelectric power generation system of the present invention includes: a starter generator with a transmission shaft; two permanent magnet speed regulators, respectively connected to both ends of the transmission shaft, each of the permanent magnet speed regulators has two rotating disks, the two rotating An air gap with adjustable size is formed between the discs, and one of the rotating discs is coaxially connected to the transmission shaft; an expander is connected to the other rotating disc of the permanent magnet governor opposite to the transmission shaft, and the expander will The internal energy of a gaseous working medium is converted into rotational kinetic energy; a compressor is connected to the other rotating disk of the permanent magnet governor opposite to the transmission shaft, and the compressor converts the rotational kinetic energy into the liquid working medium the circulating kinetic energy; an evaporator, respectively connected to the expander and the compressor, the evaporator receives the liquid working medium from the compressor, the working medium is evaporated into a gaseous state and then introduced into the expander, and a condenser, respectively Connecting the expander and the compressor, the condenser receives the gaseous working medium from the expander, and the working medium condenses into a liquid state and is then introduced into the compressor.

The working medium flow control method of the thermoelectric power generation system of the present invention includes: a motor starting step, the starter generator receives an applied current, the starter generator starts to rotate and gradually increases the rotational speed; a working medium flow step, the starter generator The air gap between the first permanent magnet governor and the compressor changes from large to small, the starter generator transmits torque to the compressor, the compressor starts to rotate and gradually accelerates, and the compressor drives the working medium Start the cycle; a turbine rotation step, the gaseous working medium works on the expander, the expander starts to rotate; a power generation step, the starter generator and the expander between the second permanent magnet governor The air gap changes from large to small, the expander transmits torque to the starter generator, the speed of the starter generator increases and switches to a power generation state; and a fine-tuning step is to adjust the air gap of the first permanent magnet governor. size, change the speed of the compressor to adjust the flow of the working medium.

Accordingly, in the thermoelectric power generation system and the method for regulating the flow rate of the working medium of the present invention, the two permanent magnet speed governors are coaxially connected to the starter generator, the expander and the compressor, so that the rotational kinetic energy can be fully utilized and the extra Moreover, by changing the size of the air gap of the two permanent magnet speed governors, the speed of the starter generator and the compressor can be adjusted, which has the functions of controlling fluid circulation and stabilizing power generation, and can be applied to Low-temperature cogeneration technology for unstable heat supply.

Wherein, the disk surfaces of the two rotating disks of each of the permanent magnet governors are opposite and not in direct contact, and the rotating shaft of one rotating disk is connected to a telescopic piece, and the rotating disk moves axially through the telescopic piece to adjust the air gap. size. In this way, the smaller the air gap, the greater the torque generated by the permanent magnet governor, which has the effect of adjusting torque and rotational speed.

Wherein, the expander has a turbine and a cavity, the turbine divides the cavity into a high pressure section and a low pressure section, the gaseous working medium enters the low pressure section from the high pressure section and drives the turbine to rotate, the turbine The rotating shaft is connected to the permanent magnet governor. In this way, the working fluid can work on the turbine, which has the effect of driving the turbine and the permanent magnet governor to rotate.

Wherein, the compressor has a power element, the rotating shaft of the power element is connected with the permanent magnet governor, and the power element pushes the liquid working medium to flow. In this way, the power element can convert the rotational kinetic energy into the kinetic energy of the liquid working medium, which has the effect of adjusting the flow rate and flow of the working medium.

In addition, a recuperator is included, and the recuperator is located at the outlet of the expander to collect the waste heat of the working medium in gaseous state. In this way, the recuperator can use the waste heat to preheat the liquid working medium entering the evaporator, which has the effect of improving the heat exchange efficiency and reusing the waste heat.

It also includes a sensing unit and a processing unit, the sensing unit detects the pressure and temperature of the working fluid entering the expander, and returns it to the processing unit, and the processing unit adjusts the gas of the permanent magnet governor gap size. In this way, the processing unit can adjust the flow rate of the working medium elastically and adaptively, which has the effect of stabilizing the fluid circulation and power generation.

The fine-tuning step detects the pressure and temperature of the working medium entering the expander, and adjusts the size of the air gap of the first permanent magnet governor according to the saturation temperature condition of the working medium to control the flow of the working medium. In this way, the working medium can be completely vaporized when entering the expander, which has the effect of generating sufficient pressure to drive rotation.

Wherein, the fine-tuning step adjusts the size of the air gap of the second permanent magnet governor, and changes the rotation speed of the starter generator to adjust the power generation. In this way, the fine-tuning step can avoid overload or shortage of the power generation of the starter generator, and has the effect of stabilizing the power generation.

Wherein, the fine-tuning step detects the rotation speed and power generation of the starter generator, and adjusts the size of the air gap of the second permanent magnet governor according to the rotation speed and power generation of the starter generator. In this way, the fine-tuning step can instantly adjust the torque of the starter generator driven by the expander, which has the effect of maintaining the rotation speed and power generation of the starter generator.

In order to make the above-mentioned and other objects, features and advantages of the present invention more obvious and easy to understand, the preferred embodiments of the present invention are exemplified below, and are described in detail as follows in conjunction with the accompanying drawings:

Please refer to FIG. 1, which is a preferred embodiment of the thermoelectric power generation system of the present invention, which includes a starter generator 1, two permanent magnet speed governors 2, an expander 3, a compressor 4, and an evaporator 5 and a condenser 6, the starter generator 1 is respectively connected to the expander 3 and the compressor 4 through the two permanent magnet speed governors 2, and the compressor 4 is sequentially connected to the evaporator 5, the expander 3 and the The condenser 6 is connected back to the compressor 4 to form a circulation path for a working medium to circulate.

Please refer to Fig. 2, the starter generator 1 has the function of combining the driving motor and the power generating device. When the current is input to a coil stator, it drives a permanent magnet rotor to rotate, which can be used as a motor; when the external power acts on the When the permanent magnet rotor is used, the permanent magnet rotor rotates relative to the coil stator, so that the coil stator generates an induced current, which can be used as a generator. The starter generator 1 has a transmission shaft 11, and the transmission shaft 11 rotates synchronously with the permanent magnet rotor.

Referring to Figures 2 and 3, the two permanent magnet speed regulators 2 are respectively connected to both ends of the drive shaft 11 of the starter generator 1, and each of the permanent magnet speed regulators 2 has two rotating disks 21, the two The disk surfaces of the rotating disks 21 are opposite and not in direct contact, so that an air gap G is formed between the two rotating disks 21. The two rotating disks 21 can be permanent magnets and electrical conductors respectively. When the two rotating disks 21 rotate relative to each other, according to the cooling time According to Lenz's Law, torque can be transmitted between the two rotating disks 21 . When one rotating disk 21 is actively rotating, the other rotating disk 21 can be driven to rotate passively through torque, and the smaller the air gap G is, the smaller the air gap G will be. more torque. Each of the permanent magnet governors 2 has a telescopic element 22 , the telescopic element 22 is connected to the rotating shaft of one of the rotating disks 21 , and the rotating shaft of the other rotating disk 21 is connected to the transmission shaft 11 , so that the two rotating disks 21 , The telescopic element 22 and the transmission shaft 11 can rotate coaxially, and the telescopic element 22 can be elongated or shortened in the axial direction, which can move the rotating disk 21 in the axial direction to adjust the size of the air gap G, and has an adjustable torque and the effect of speed.

Referring to FIG. 2 , the expander 3 has a turbine 31 and a cavity 32 , the turbine 31 is located in the cavity 32 , and the cavity 32 is divided into a high-pressure section 33 and a low-pressure section by the turbine 31 In section 34, by introducing a high-temperature and high-pressure gaseous working medium into the high-pressure section 33, the working medium passes through the turbine 31 and performs work on the turbine 31 to drive the turbine 31 to rotate, and the working medium consumes energy to form A relatively low temperature and low pressure gaseous working medium enters the low pressure section 34 . Please refer to FIG. 3 again, the rotating shaft of the turbine 31 is connected to the telescopic element 22 of the permanent magnet governor 2 , so that the turbine 31 , the telescopic element 22 and the rotating disk 21 connected to the telescopic element 22 can be coaxial rotate.

Referring to Figures 2 and 3, the compressor 4 has a power element 41, and the rotating shaft of the power element 41 is connected to the telescopic element 22 of the permanent magnet governor 2, so that the power element 41, the telescopic element 22 The rotating disk 21 connected to the telescopic element 22 can rotate coaxially. The power element 41 can be a pump impeller. When the power element 41 rotates, it can transfer energy to the liquid working medium passing through the compressor 4, so that the flow rate of the working medium can be increased to obtain kinetic energy, or the temperature of the working medium can be increased. The system obtains internal energy, and the compressor 4 has the function of adjusting the flow rate of the working medium.

Referring to FIG. 1 , the evaporator 5 exchanges heat with a heat source. The evaporator 5 receives a low-temperature liquid working medium from the compressor 4 , and the working medium absorbs the heat source provided in the evaporator 5 . The heat energy evaporates the working medium into a gaseous state and increases the temperature and pressure. The evaporator 5 then introduces the high-temperature and high-pressure gaseous working medium into the expander 3 .

The condenser 6 exchanges heat with a cold source, the condenser 6 receives the gaseous working medium from the expander 3, and the cold source absorbs the heat energy of the working medium through the condenser 6 to condense the working medium into a liquid state, The condenser 6 then introduces the liquid working substance into the compressor 4 .

The energy source of the thermoelectric power generation system of the present invention is that the external current is input to the starter generator 1 to drive the motor to rotate, and the expander 3 receives the internal energy of the working medium and converts it into rotational kinetic energy, and then uses the two permanent magnet speed governors. 2. Transfer the rotational kinetic energy to the starter-generator 1 and the compressor 4 in sequence. The starter-generator 1 converts kinetic energy into electrical energy for storage or use through the generator function, and the compressor 4 converts the rotational kinetic energy into the working fluid. kinetic energy and internal energy, and drive the working medium to circulate; in addition, the working medium absorbs heat energy in the evaporator 5 and changes from liquid to gaseous state, and then the working medium releases energy in the expander 3 and the condenser 6, and After the condenser 6 changes from gas to liquid, and the working medium returns to liquid state, the compressor 4 controls the flow and re-enters the working medium into the evaporator 5 to form a cycle.

The thermoelectric power generation system of the present invention may also have a recuperator, and the recuperator may be located at the outlet of the expander 3 (not shown in the figure), and the waste heat discharged from the working medium in the gaseous state of the expander 3 consumes energy. Collected by the reheater, the waste heat is used by the reheater to preheat the liquid working medium entering the evaporator 5, and the waste heat can also be used for heating devices such as water heaters or heating.

The thermoelectric power generation system of the present invention may also have a sensing unit located in the expander 3 (not shown in the figure), and the sensing unit detects the pressure and temperature of the working medium entering the expander 3 and returns it to a processing unit unit, the processing unit changes the size of the air gap G of the permanent magnet governor 2 according to the pressure and temperature changes of the working medium, and can control the flow rate of the working medium by adjusting the speed of the compressor 4 to Ensuring that the working medium can be completely vaporized when entering the expander 3, avoiding the coexistence of the working medium in the expander 3 and the inability to generate sufficient pressure to drive the expander 3 to rotate, and has the effect of elastically self-adjusting the flow of the working medium.

Please refer to Figures 4 and 5, which are preferred embodiments of the method for regulating the working fluid flow of the thermoelectric power generation system of the present invention, which include a motor starting step S1, a working fluid flow step S2, a turbine rotating step S3, A power generation step S4 and a fine-tuning step S5.

In the motor starting step S1, the starter-generator 1 receives an applied current in a motor state, so that the starter-generator 1 starts to rotate and gradually increases the rotational speed.

The working fluid flow step S2 is to transmit the torque of the starter generator 1 to the compressor 4 through the first permanent magnet governor 2a between the starter generator 1 and the compressor 4, so that the compressor 4 Start to rotate and gradually accelerate, the compressor 4 can drive the working medium to start circulation, and the acceleration of the rotation speed of the starter generator 1 slows down. When the rotation speed of the starter generator 1 and the compressor 4 reaches a stable state, the The rotational speed of the starter generator 1 is greater than the rotational speed of the compressor 4 . In this embodiment, the air gap G of the first permanent magnet governor 2a is changed from large to small, so that the torque of the starter generator 1 to drive the compressor 4 is gradually increased.

In the turbine rotating step S3, the gaseous working medium performs work on the expander 3, so that the expander 3 starts to rotate. The flow rate of the working medium passing through the expander 3 is positively correlated with the rotational speed of the expander 3. When the flow rate of the working medium is stable, the expander 3 can rotate at a constant speed.

The power generation step S4 is to transmit the torque of the expander 3 to the starter generator 1 through the second permanent magnet governor 2b between the starter generator 1 and the expander 3, so that the starter generator 1 can When the rotation speed increases, the starter generator 1 can be switched from the motor state to the power generation state. Since the starter generator 1, the expander 3 and the compressor 4 rotate coaxially through the two permanent magnet speed governors 2a and 2b, the The rotational speed of the compressor 4 increases, and the expander 3 transmits torque to the starter generator 1 and the compressor 4 in sequence, which will cause the rotational speed of the expander 3 to decrease. In this embodiment, the air gap G of the second permanent magnet governor 2b is changed from large to small, so that the torsion force of the starter generator 1 driven by the expander 3 is gradually increased.

In the fine-tuning step S5, by adjusting the size of the air gap G of the first permanent magnet governor 2a, the speed of the compressor 4 is controlled to change the flow rate of the working medium, which can ensure that the working medium enters the expander At 3, it can be completely vaporized, avoiding the coexistence of liquid and gas in the working fluid in the expander 3 and unable to generate sufficient pressure to drive the expander 3 to rotate. In addition, when the rotation speed of the starter generator 1 is too high and the power generation is overloaded, by increasing the air gap G of the second permanent magnet governor 2b, the rotation speed of the starter generator 1 can be reduced; when When the rotation speed of the starter generator 1 is too low and the power generation is insufficient, the air gap G of the second permanent magnet governor 2b can be adjusted to increase the rotation speed of the starter generator 1. Therefore, the adjustment of the The size of the air gap G of the second permanent magnet governor 2b has the function of controlling the rotational speed of the starter generator 1 and supplying stable power generation.

In addition, the fine-tuning step S5 can also detect the pressure and temperature of the working fluid entering the expander 3, control the flow rate of the working fluid according to the saturation temperature condition of the working fluid, and detect the rotational speed and power generation of the starter generator 1 to adjust the torque of the starter generator 1 driven by the expander 3 in real time. When the thermal energy supplied by the heat source is unstable, the fine-tuning step S5 can maintain the working medium circulation and stabilize the power generation by adjusting the two permanent magnet speed regulators 2a and 2b.

To sum up, the thermoelectric power generation system and the working medium flow control method of the present invention can make full use of the rotational kinetic energy by coaxially connecting the starter generator, the expander and the compressor through the two permanent magnet speed governors. Reduce extra energy consumption, and through the detector, the temperature and pressure input to the expander can be detected in real time, and the values can be fed back to adjust the air gap size of the first permanent magnet governor, so that the compressor can be It can adjust the flow of working medium elastically and adaptively. Even if the heat source is unstable, the system can still run stably and efficiently.

Although the present invention has been disclosed by the above-mentioned preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications relative to the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the patent application attached hereto.

1: Start the generator 11: Transmission shaft 2: Permanent magnet governor 2a: The first permanent magnet governor 2b: Second permanent magnet governor 21: Turn the disc 22: Telescopic parts 3: Expander 31: Turbo 32: Cavity 33: High pressure section 34: low pressure section 4: Compressor 41: Power components 5: Evaporator 6: Condenser G: air gap S1: Motor start step S2: Working fluid flow step S3: Turbine Rotation Step S4: Power Generation Step S5: Fine-tuning step

[FIG. 1] A system block diagram of a preferred embodiment of the present invention. [FIG. 2] An enlarged view of a partial structure of a preferred embodiment of the present invention. [Fig. 3] A partial perspective view as shown in Fig. 2. [FIG. 4] A step situation diagram of a preferred embodiment of the present invention. [Fig. 5] A graph showing the change in rotational speed of each element in each step as shown in Fig. 4.

1: Start the generator

2: Permanent magnet governor

3: Expander

4: Compressor

5: Evaporator

6: Condenser

Claims (10)

A thermoelectric power generation system, comprising: a starter generator with a drive shaft; Two permanent magnet speed governors are respectively connected to the two ends of the transmission shaft, each of the permanent magnet speed governors has two rotating disks, an air gap of adjustable size is formed between the two rotating disks, and one of the rotating disks is coaxially connected to the transmission shaft; an expander, connected to the other rotating disk of the permanent magnet governor relative to the transmission shaft, the expander converts the internal energy of a gaseous working medium into rotational kinetic energy; a compressor, connected to the other rotating disk of the permanent magnet governor opposite to the transmission shaft, the compressor converts the rotational kinetic energy into the circulating kinetic energy of the working medium in liquid state; an evaporator, respectively connected to the expander and the compressor, the evaporator receives the working medium in liquid state from the compressor, the working medium is evaporated into a gaseous state and then introduced into the expander, and A condenser is respectively connected to the expander and the compressor. The condenser receives the gaseous working medium from the expander, and the working medium is condensed into a liquid state and then introduced into the compressor. The thermoelectric power generation system of claim 1, wherein the disk surfaces of the two rotating disks of each of the permanent magnet governors are opposite to each other and not in direct contact, and one of the rotating shafts of the rotating disk is connected to a telescopic element, and the rotating disk passes through the telescopic element Make an axial movement to adjust the size of the air gap. The thermoelectric power generation system of claim 1, wherein the expander has a turbine and a cavity, the turbine divides the cavity into a high pressure section and a low pressure section, and the gaseous working medium enters the low pressure from the high pressure section segment and drive the turbine to rotate, and the rotating shaft of the turbine is connected to the permanent magnet governor. The thermoelectric power generation system of claim 1, wherein the compressor has a power element, the rotating shaft of the power element is connected to the permanent magnet governor, and the power element pushes the liquid working medium to flow. The thermoelectric power generation system of claim 1 further comprises a recuperator, the recuperator is located at the outlet of the expander to collect the waste heat of the gaseous working medium. As claimed in claim 1, the thermoelectric power generation system further includes a sensing unit and a processing unit, the sensing unit detects the pressure and temperature of the working fluid entering the expander, and returns them to the processing unit, and the processing unit adjusts The size of the air gap of the permanent magnet governor. A working medium flow control method for a thermoelectric power generation system, using the thermoelectric power generation system according to any one of claim items 1 to 6, comprising: a motor starting step, the starter generator receives the applied current, the starter generator starts to rotate and gradually increases the speed; In a working fluid flow step, the air gap of the first permanent magnet governor between the starter generator and the compressor changes from large to small, the starter generator transmits torque to the compressor, the compressor starts to rotate and Gradually accelerate, the compressor drives the working medium to start circulation; In a turbine rotation step, the gaseous working medium performs work on the expander, and the expander starts to rotate; In a power generation step, the air gap of the second permanent magnet governor between the starter generator and the expander changes from large to small, the expander transmits torque to the starter generator, the speed of the starter generator increases and switch to the generating state; and In a fine-tuning step, the size of the air gap of the first permanent magnet governor is adjusted, and the rotational speed of the compressor is changed to adjust the flow rate of the working medium. The method for regulating the flow rate of working medium of a thermoelectric power generation system as claimed in claim 7, wherein the fine-tuning step detects the pressure and temperature of the working medium entering the expander, and adjusts the first permanent magnet speed regulation according to the saturation temperature condition of the working medium The size of the air gap of the device is used to control the flow of the working medium. The working medium flow control method for a thermoelectric power generation system as claimed in claim 7, wherein the fine adjustment step adjusts the size of the air gap of the second permanent magnet governor, and changes the rotation speed of the starter generator to adjust the power generation. The working medium flow control method for a thermoelectric power generation system as claimed in claim 9, wherein the fine-tuning step detects the rotational speed and power generation of the starter-generator, and adjusts the second permanent magnet speed regulation according to the rotational speed and power generation of the starter-generator The size of the air gap in the device.

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