JP6862514B2 - Compressed air storage power generator - Google Patents

Description

The present invention relates to a compressed air storage power generation device.

Compressed air energy storage (CAES) is known as one of the techniques for smoothing or leveling the fluctuating unstable power generation output. In a CAES power generation device using this technology, compressed air is generated by driving a compressor with an electric motor using electric power. The generated compressed air is temporarily stored, and when electric power is required, the stored compressed air is used to operate an expander (turbine) to drive a generator to generate electricity.

Patent Document 1 discloses a CAES power generation device that uses both a compressor and an expander.

Special Table 2013-509529

Patent Document 1 does not mention a method of performing rated operation at a wide range of pressure regardless of whether charging operation or power generation operation is performed in a CAES power generation device using a compression / expansion combined machine.

The CAES power generator is required to have a wide range of rated operating capacities. However, in the CAES power generation device using the compression / expansion combined machine, the efficiency of the charging operation (compression operation) is higher than the efficiency of the power generation operation (expansion operation), so that it is difficult to realize a wide range of rated operations. Specifically, the amount of power that can be generated from 1 kg of compressed air (specific power generation amount) is generally smaller than the amount of power required to generate 1 kg of compressed air (specific charge power amount) (hereinafter). , The specific charge electric energy or the specific power generation amount is also simply called the specific electric energy). Therefore, in order to realize the rated operation, conventionally, it has been necessary to control the charging operation and the power generation operation separately. In addition, since the specific electric energy changes depending on the operating pressure (pressure of the stored compressed air), it is necessary to control according to the operating pressure in order to execute the rated operation at a wide range of pressures in the past. It was.

An object of the present invention is to realize rated operation in a wide range of pressures regardless of whether charging operation or power generation operation is performed in a compressed air storage power generation device using a compression / expansion combined machine.

Ｕｍａｘ：前記圧縮膨張兼用機の許容最高回転速度（ｍ／ｓ）又はピストン許容周速（ｍ／ｓ）
Ｎｐ：前記電動発電兼用機の極数
Ｄ：前記圧縮膨張兼用機のロータ外径（ｍ）又はクランク回転径（ｍ）
Ｒｍａｘ：最大変速比

を備える、圧縮空気貯蔵発電装置を提供する。 The present invention
A compression / expansion machine that has a function as a compressor that compresses air and a function as an expander that expands compressed air,
A motor generator that is mechanically connected to the compression / expansion machine and has a function as an electric motor that drives the compression / expansion machine and a function as a generator that is driven by the compression / expansion machine.
A pressure accumulator that is fluidly connected to the compression / expansion machine and stores compressed air generated by the compression / expansion machine.
A transmission unit provided between the compression / expansion combined machine and the motor generator combined machine and having a gear ratio R in the range of the following formula,

Umax: Allowable maximum rotation speed (m / s) or piston allowable peripheral speed (m / s) of the compression / expansion combined machine.
Np: Number of poles of the motor generator
D: Rotor outer diameter (m) or crank rotation diameter (m) of the compression / expansion combined machine
Rmax: maximum gear ratio

Provided is a compressed air storage power generation device.

According to this configuration, based on the allowable maximum rotation speed or piston allowable peripheral speed of the compression / expansion combined machine, the number of poles of the electric power generation combined machine, and the rotor diameter or crank rotation diameter of the compression / expansion combined machine, the compression / expansion combined use is performed. The range of the power transmission ratio (gear ratio R) between the machine and the machine for electric power generation is specified. The range of the gear ratio R is defined from the following two points that affect the specific electric energy. The first is the distinction between the charging operation and the power generation operation, and the second is the filling rate of the accumulator. In consideration of these, in order to secure the rated charging power amount and generated power amount in a wide range, it is necessary to be able to change the rotation speed of the compression / expansion combined machine in a wide range. On the other hand, by defining the gear ratio R in the above range (0.7Rmax ≦ R ≦ Rmax), the rotation speed of the compression / expansion combined machine can be changed within a necessary range. As a result, the rated charging power amount and generated power amount can be secured in a wide operating range. That is, the rated operation can be realized in a wide range of pressures regardless of whether the charging operation or the power generation operation is performed.

In the compressed air storage power generation device, in the power generation operation in which the motor generator functions as a generator, the compression / expansion machine has the maximum rotation speed or the maximum peripheral speed of the piston when the filling rate of the pressure accumulator is 0%. It may be set to drive.

According to this configuration, the compression / expansion combined machine is set to be driven at the maximum rotation speed or the maximum peripheral speed of the piston when the filling rate of the accumulator in the power generation operation is 0% and the specific power generation amount is the smallest. .. Here, the filling rate of 0% is the power generation limit value, that is, the state of the storage pressure in which the storage pressure in the accumulator is small and the power cannot be generated at a pressure lower than this, or the power generation is less than the allowable efficiency. Say. Therefore, by driving the compression / expansion combined machine at the maximum rotation speed or the maximum peripheral speed of the piston in this state, it is possible to secure as much power generation as possible in the state, and to obtain the rated power generation amount in a wide range of filling rates. Can be secured.

The maximum rotational speed or the maximum peripheral speed of the piston may be the allowable maximum rotational speed of the compression / expansion combined machine or the allowable peripheral speed of the piston.

According to this configuration, the operation that suitably utilizes the allowable maximum rotation speed or the permissible peripheral speed of the piston of the compression / expansion combined machine becomes possible, and the rated operation in a wide range of filling rates becomes possible.

In the compressed air storage power generation device, in the charging operation in which the motor generator functions as an electric motor, the compressor / expansion machine is driven at the minimum rotation speed or the minimum peripheral speed of the piston when the filling rate of the pressure accumulator is 100%. May be set to.

According to this configuration, when the filling rate of the accumulator portion in the charging operation is 100%, the compression / expansion combined machine is set to have the minimum rotation speed or the minimum peripheral speed of the piston. Here, the filling rate of 100% is the accumulator limit value, that is, the pressure in the accumulator portion has reached the maximum permissible pressure. Therefore, by setting the rotation speed of the compression / expansion combined machine to the minimum rotation speed or the minimum peripheral speed of the piston in this state, the rated charging power amount can be secured in a wide range.

The minimum rotational speed or the minimum peripheral speed of the piston may be 0.4 times or more the allowable maximum rotational speed of the compression / expansion combined machine or the allowable peripheral speed of the piston.

According to this configuration, the minimum rotational speed or the minimum peripheral speed of the piston is set to 0.4 times or more the allowable maximum rotational speed of the piston. As a result, the compression / expansion combined machine can be operated within the allowable operating temperature. Specifically, when the compressor / expansion machine operates as a compressor, some of the compressed air is discharged (high pressure) due to the pressure difference between the intake port (low pressure port) and the discharge port (high pressure port) of the compression / expansion machine. Backflow from the port) to the air intake (low pressure port). Since the flow rate of this backflowing air is almost constant regardless of the rotation speed of the rotor or the peripheral speed of the piston, the lower the rotation speed or the peripheral speed of the piston, the greater the ratio of the backflowing air to the air taken in from the atmosphere. .. Therefore, the internal temperature of the compression / expansion combined machine becomes higher as the rotation speed or the peripheral speed of the piston becomes lower, and the discharge temperature also rises. Therefore, in order to keep the internal temperature and the discharge temperature of the compression / expansion combined machine within the allowable operating temperature, it is necessary to keep the minimum rotation speed or the minimum peripheral speed of the piston at a certain level or higher. For example, such a minimum rotational speed or a minimum peripheral speed of a piston is 0.4 times or more an allowable maximum rotational speed or an allowable peripheral speed of a piston as described above.

The compression / expansion combined machine may be a screw type.

According to this configuration, the amount of charging power and the amount of generated power can be adjusted by adjusting the rotation speed of the screw rotor, so that the required power (required charging power or generated power) that fluctuates irregularly can be followed with good responsiveness. , Can provide a CAES power generator with a wide operating range.

According to the present invention, in a compressed air storage power generation device using a compression / expansion combined machine, rated operation can be realized with a wide range of pressure regardless of whether charging operation or power generation operation is performed.

The schematic block diagram of the CAES power generation apparatus which concerns on embodiment of this invention. The graph which shows the specific electric energy with respect to the operating pressure of a CAES power generation apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

With reference to FIG. 1, the CAES power generation device 1 receives power from a power generation facility 2 that generates power using renewable energy, performs a charging operation, and performs a power generation operation in accordance with the power demand. That is, the CAES power generation device 1 equalizes irregular output fluctuations of the power generation facility 2 and supplies power according to the power demand.

In this embodiment, a wind power generation facility is exemplified as a power generation facility 2 that generates power using renewable energy. However, the type of renewable energy targeted by the CAES power generation device 1 is not limited to this, and is constantly or repeatedly generated by natural forces such as sunlight, solar heat, wave power, tidal power, running water, or tide. It can cover all power generation using replenished and irregularly fluctuating energy. Furthermore, in addition to renewable energy, it can be applied to all factories whose power generation amount fluctuates, such as factories having power generation facilities that operate irregularly.

The CAES power generation device 1 includes a compression / expansion combined machine 10, an electric power generation combined machine 20, a pressure accumulator 30, and a control device 40.

The compression / expansion combined machine 10 has a function as a compressor for compressing air and a function as an expander for expanding compressed air. Further, the compression / expansion combined machine 10 has a low pressure port 11 and a high pressure port 12. When the compressor / expansion machine 10 functions as a compressor, air is taken in from the low pressure port 11, the air is compressed inside, and compressed air is discharged from the high pressure port 12. When the compression / expansion combined machine 10 functions as an expander, compressed air is supplied from the high pressure port 12, the compressed air is expanded inside, and air is exhausted from the low pressure port 11.

In the present embodiment, the compression / expansion combined machine 10 is a screw type. Since the screw type compression / expansion combined machine 10 can control the rotation speed of the internal screw rotor, it can responsively follow the required power (required charging power or generated power) that fluctuates irregularly. Therefore, the screw type compression / expansion combined machine 10 is preferable as a component of the CAES power generation device 1. Further, the compression / expansion combined machine 10 can be easily configured by using the screw rotor for both compression and expansion and rotating the screw rotors in opposite directions for compression and expansion. However, the compression / expansion combined machine 10 is not limited to the screw type, and may be a rotary type or a reciprocating type. The rotary type here includes all types such as a screw type, a centrifugal type, an axial flow type, or a scroll type. The reciprocating type includes all types such as a piston type or a diaphragm type.

The motor generator 20 is mechanically connected to the compression / expansion machine 10 via the transmission unit 21. The electric power generation combined machine 20 has a function as an electric motor (motor) for operating the compression / expansion combined machine 10 as a compressor and a function as a generator driven by the compression / expansion combined machine 10 operating as an expander.

The power generation facility 2 is electrically connected to the motor generator 20. In the charging operation, the motor generator 20 functions as a motor generator and is driven by the fluctuating input power from the power generation facility 2.

The motor generator 20 is also electrically connected to a power system (not shown). In the power generation operation, the electric power generation combined machine 20 functions as a generator, and the generated output power is transmitted to the power system.

The operation of the motor generator 20 is controlled by the control device 40. Specifically, the inverter 22 is electrically connected to the motor generator 20. The inverter 22 is controlled by the control device 40. Therefore, the control device 40 controls the rotation speed of the motor generator 20 by the inverter 22.

The transmission unit 21 changes the transmission ratio (gear ratio) of the rotational power between the compression / expansion combined machine 10 and the motor generator combined machine 20. The transmission unit 21 is, for example, a transmission gear, and the gear ratio can be changed by engaging gears having different numbers of teeth. In the present embodiment, the transmission unit 21 has a gear ratio R in the range of the following formula. In this embodiment, since the screw type (an example of the rotary type) compression / expansion combined machine 10 is used, the term “rotational speed” is used. Alternatively, when using the piston type compression / expansion machine 10, "rotation speed" should be read as "piston peripheral speed" and "rotor outer diameter" should be read as "crank rotation diameter". The description and formula of are applicable as well.

Ｕｍａｘ：圧縮膨張兼用機１０の許容最高回転速度（ｍ／ｓ）
Ｎｐ：電動発電兼用機２０の極数
Ｄ：圧縮膨張兼用機１０のロータ外径（雄側スクリュロータの最外径）（ｍ）
Ｒｍａｘ：最大変速比

Umax: Allowable maximum rotation speed (m / s) of the compression / expansion combined machine 10
Np: Number of poles of motor generator 20
D: Rotor outer diameter of compression / expansion machine 10 (outer diameter of male screw rotor) (m)
Rmax: maximum gear ratio

Regarding the derivation of the above equation, the maximum gear ratio Rmax is known in the art. The minimum value of the gear ratio R is set to 0.7Rmax for the following reasons. When the gear ratio R is examined in an actual machine, for example, in the two-pole motor generator 20 (that is, when Np = 2), the rotation speed is set to 88 [m / S] to 120 [m / S]. A suitable operation could be realized. The gear ratio R at this time is 2.8 to 3.8, and the ratio of the minimum gear ratio (2.8) to the maximum gear ratio (3.8) is 0.7. Further, it was confirmed that suitable operation can be realized by defining the gear ratio R to be 70% or more of the maximum gear ratio Rmax even in the case of other poles Np.

Further, the pressure accumulator portion 30 is fluidly connected to the compression / expansion combined machine 10 via a three-way valve 31 and a check valve 32. The pressure accumulator portion 30 is a portion that stores compressed air. The accumulator 30 may be, for example, a steel tank. The number of pressure accumulators 30 is not particularly limited, and a plurality of tanks may be provided. Further, the pressure accumulator 30 does not necessarily have to be in the form of a tank. Alternatively, it may be able to store compressed air, such as a closed underground cavity. By switching the three-way valve 31, it is possible to select whether to supply compressed air from the compression / expansion combined machine 10 to the accumulator 30 or from the accumulator 30 to the compression / expansion combined machine 10. Further, the three-way valve 31 may have a flow rate adjusting function.

A pressure sensor 33 is attached to the pressure accumulator portion 30. The pressure sensor 33 can measure the pressure inside the accumulator 30. Therefore, the filling rate of the pressure accumulator 30 can be measured by the pressure sensor 33. Here, the measured pressure data is sent to the control device 40 and used for the control described later.

A heat exchanger 50 is interposed between the compression / expansion machine 10 and the accumulator 30. A heat medium is supplied to the heat exchanger 50, and the heat exchanger 50 exchanges heat between the heat medium and air. Therefore, in the heat exchanger 50, the air is heated or cooled by the heat medium as needed.

The heat exchanger 50 is fluidly connected to the high temperature heat medium tank 51 and the low temperature heat medium tank 52. The high-temperature heat medium tank 51 is a tank for storing a relatively high-temperature heat medium, and the low-temperature heat medium tank 52 is a tank for storing a relatively low-temperature heat medium. Here, the type of heat medium is not particularly limited, but may be, for example, water or oil.

A heat medium pump 53 is arranged in a heat medium flow path that fluidly connects the high temperature heat medium tank 51 and the low temperature heat medium tank 52 via the heat exchanger 50. The heat medium pump 53 can supply a high temperature heat medium from the high temperature heat medium tank 51 to the heat exchanger 50, and can supply a low temperature heat medium from the low temperature heat medium tank 52 to the heat exchanger 50. The flow rate of the heat medium supplied to the heat exchanger 50 by the heat medium pump 53 may be adjusted to adjust the amount of heat exchange.

The operation operation of the CAES power generation device 1 having the above configuration will be described.

When the CAES power generation device 1 performs the charging operation, the motor generator 20 is driven as an electric motor by the input power from the power generation facility 2. Rotational power is transmitted from the motor generator 20 driven as an electric motor to the compression / expansion machine 10 via the transmission unit 21, and the motor generator 10 drives the compression / expansion machine 10 as a compressor. Therefore, in the charging operation, the compression / expansion combined machine 10 takes in air from the low-pressure port 11 using electric power, compresses the taken-in air, and discharges the compressed air from the high-pressure port 12. The discharged compressed air is stored in the accumulator 30.

In the charging operation, the heat medium pump 53 supplies a low temperature heat medium from the low temperature heat medium tank 52 to the heat exchanger 50. In the heat exchanger 50, the low-temperature heat medium supplied from the low-temperature heat medium tank 52 and the high-temperature compressed air heated by the heat of compression exchange heat. As a result, the compressed air is cooled and the heat medium is heated. Therefore, the compressed air is sent to the accumulator 30 and stored in a cooled and cooled state. On the other hand, the heat medium is sent to and stored in the high temperature heat medium tank 51 in a state of being heated and heated.

When the CAES power generation device 1 performs power generation operation, compressed air is supplied from the accumulator unit 30 to the high pressure port 12 of the compression / expansion combined machine 10. The compressed air supplied to the compressor drives the compression / expansion machine 10 as an expander, and the rotational power is transmitted from the compression / expansion machine 10 to the electric power generator 20 via the transmission 21 and is electrically operated by the compression / expansion machine 10. The power generation combined machine 20 is driven as a generator. Therefore, in the power generation operation, compressed air is supplied from the accumulator 30 to the high pressure port 12, the compressed air is expanded in the compression / expansion combined machine 10, and the expanded air is exhausted from the low pressure port 11.

In the power generation operation, the heat medium pump 53 supplies the high temperature heat medium from the high temperature heat medium tank 51 to the heat exchanger 50. In the heat exchanger 50, the high-temperature heat medium supplied from the high-temperature heat medium tank 51 to the heat exchanger 50 and the compressed air supplied from the accumulator 30 exchange heat. As a result, the compressed air is heated and the heat medium is cooled. Therefore, the compressed air is sent to the compression / expansion combined machine 10 in a state of being heated and heated, and is expanded. On the other hand, the heat medium is sent to the low temperature heat medium tank 52 and stored in a cooled and cooled state.

FIG. 2 is a graph showing the amount of specific power with respect to the operating pressure of the CAES power generation device. In FIG. 2, the horizontal axis represents the operating pressure, and the vertical axis represents the specific electric energy (specific electric energy or specific generated electric energy). The pressure Pmin indicates the pressure when the filling rate of the accumulator 30 is 0%, that is, the lower limit of the pressure that air with a pressure lower than this value cannot generate electricity. The pressure Pmax indicates the pressure when the filling rate of the accumulator 30 is 100%, that is, the upper limit of the pressure at which air having a pressure higher than this value cannot be stored. In the graph, a curve showing the specific electric energy SPC in the charging operation and a curve showing the specific electric energy SPG in the power generation operation are drawn. Further, the pressures P0, P1 and P2 indicate the pressure between the pressure Pmin and the pressure Pmax, and are the pressures increasing in this order (Pmin <P0 <P1 <P2 <Pmax).

In FIG. 2, the rotation speeds Rc4, Rc1, Rc2, and Rc3 of the compression / expansion combined machine 10 corresponding to the respective pressures Pmin, P1, P2, and Pmax in the charging operation are shown as subscripts, respectively. Similarly, the rotation speeds Rg1, Rg2, Rg3, and Rg4 of the compression / expansion combined machine 10 corresponding to the respective pressures Pmin, P1, P2, and Pmax in the power generation operation are shown as subscripts, respectively.

As can be seen from the fact that the specific electric energy SPC is located above the specific electric energy SPG in FIG. 2, due to the characteristics of the compression / expansion combined machine, the specific electric energy required for the charging operation is the specific electric energy generated by the power generation operation. Higher than quantity. In the present embodiment, the rotation speeds Rc1 to Rc4 of the compression / expansion combined machine 10 in the charging operation are set to be smaller than the rotation speeds Rg1 to Rg4 of the compression / expansion combined machine 10 in the power generation operation (Rc1 to Rc4 <Rg1 to Rg4). .. As a result, the actual amount of charging power and the actual amount of generated power are almost the same. Therefore, the same amount of charging power and the amount of generated power can be secured in the charging operation and the power generation operation, and the rated operation can be executed.

Further, as can be seen with reference to FIG. 2, the specific electric power amount of the compression / expansion combined machine 10 changes according to the filling rate of the accumulator portion 30 (that is, the operating pressure on the horizontal axis of FIG. 2). In the present embodiment, in order to obtain a constant charging power amount and generated power amount regardless of the storage pressure of the accumulator unit 30, the rotation speed of the compression / expansion combined machine 10 is changed according to the storage pressure of the accumulator unit 30. There is.

Specifically, for example, in the charging operation, the rotation speeds Rc1, Rc2, and Rc3 when the operating pressures are P1, P2, and Pmax are set to decrease in this order (Rc1> Rc2> Rc3). That is, the rotation speed is set to decrease as the specific charge electric energy SPC increases. Further, for example, in the power generation operation, the rotation speeds Rg1, Rg2, Rg3, Rg4 of the compression / expansion combined machine 10 when the operating pressures Pmin, P1, P2, Pmax (Pmin <P1 <P2 <Pmax) are reduced in this order. (Rg1> Rg2> Rg3> Rg4) is set. That is, the rotation speed is set to decrease as the specific power generation amount SPG increases. As a result, the same charging power amount and generated power amount can be secured regardless of the storage pressure of the pressure accumulating unit 30, and the rated operation can be executed.

Note that FIG. 2 shows a graph relating to a two-stage compression / expansion machine. In the graph, the specific charge electric energy SPC does not simply increase according to the operating pressure. That is, when the pressure is less than the pressure P0, the specific charging electric energy SPC increases as the operating pressure decreases. This indicates that the pressure P0 is the design discharge pressure of the low pressure stage. Therefore, the rotation speed Rc4 of the compression / expansion combined machine 10 at the pressure Pmin is set lower than the rotation speed Rc1 at the pressure P1 (Rc4 <Rc1). However, the present invention is not limited to either the single-stage type or the multi-stage type.

In this way, by adjusting the rotation speed of the compression / expansion combined machine 10, in order to perform the rated operation from the pressure Pmin to the pressure Pmax regardless of whether the charging operation or the power generation operation is performed, the transmission unit 21 is in the above range (0). It is necessary to have a gear ratio R of .7 Rmax ≦ R ≦ Rmax). Thereby, the required rotation speeds Rg1 to Rg4 and Rc1 to Rc4 can be realized. That is, according to the present embodiment, the compression / expansion combined use is performed based on the allowable maximum rotation speed Umax of the compression / expansion combined machine 10, the number of poles Np of the motor generator combined machine 20, and the rotor diameter D of the compression / expansion combined machine 10. The range of the power transmission ratio (gear ratio R) between the machine 10 and the motor generator 20 is defined. The range of the gear ratio R is defined from the following two points that affect the specific electric energy. The first is the distinction between the charging operation and the power generation operation, and the second is the filling rate of the accumulator 30. In consideration of these, in order to secure the rated charging power amount and generated power amount in a wide range, it is necessary to change the rotation speed of the compression / expansion combined machine 10 in a wide range. On the other hand, by defining the gear ratio R in the above range (0.7Rmax ≦ R ≦ Rmax), the rotation speed of the compression / expansion combined machine 10 can be changed in a wide range, and the rated charging power amount and the rated charging power amount in a wide range and The amount of generated power can be secured.

Preferably, the conditions of the maximum rotation speed and the minimum rotation speed of the compression / expansion combined machine 10 are set as follows for the CAES power generation device 1 that performs the above operation operation.

Regarding the maximum rotation speed, in the power generation operation, the rotation speed Rg1 of the compression / expansion combined machine 10 when the filling rate of the accumulator 30 is 0% (that is, when the pressure is Pmin) is set to be the maximum rotation speed. That is, when the specific power generation amount at which the filling rate of the accumulator is 0% is the smallest, the rotation speed of the compression / expansion combined machine 10 is set to the maximum rotation speed. As a result, the amount of generated power can be secured as much as possible.

More preferably, the maximum rotation speed is set to be the allowable maximum rotation speed of the compression / expansion combined machine 10. As a result, it is possible to operate by suitably utilizing the maximum allowable rotation speed of the compression / expansion combined machine 10, and it is possible to perform rated operation in a wide range of operating pressures (filling rate of the accumulator 30).

Regarding the minimum rotation speed, in the charging operation, the rotation speed of the compression / expansion combined machine 10 when the filling rate of the accumulator 30 is 100% (that is, when the pressure is Pmax) is set to be the minimum rotation speed. As a result, the rated charging electric energy can be secured in a wide range of operating pressures (filling rate of the accumulator 30).

More preferably, the minimum rotation speed is set to be 0.4 times or more the allowable maximum rotation speed of the compression / expansion combined machine 10. As a result, the compression / expansion combined machine 10 can be operated within the allowable operating temperature. Specifically, in the compression operation, the compressed air originally flows from the low pressure port 11 to the high pressure port, but due to the pressure difference between the low pressure port 11 and the high pressure port 12 of the compression / expansion combined machine 10, some of the compressed air becomes the high pressure port. Backflow from 12 to the low pressure port 11. Since the amount of backflow air is almost constant regardless of the rotation speed of the screw rotor, the smaller the rotation speed, the greater the ratio of the backflow air to the air taken in from the atmosphere. Therefore, the internal temperature of the compression / expansion combined machine 10 becomes higher as the rotation speed becomes smaller, and the discharge temperature also rises. Therefore, in order to keep the internal temperature and the discharge temperature of the compression / expansion combined machine 10 within the allowable operating temperature, it is necessary to keep the minimum rotation speed at a certain level or higher. For example, such a minimum rotation speed is 0.4 times or more the allowable maximum rotation speed.

As described above, in the CAES power generation device 1 using the compression / expansion combined machine 10, the rated operation can be realized in a wide range of pressures (Pmin to Pmax) regardless of whether the charging operation or the power generation operation is performed.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

For example, the filling rate of the pressure accumulator 30 is not limited to the one in which the pressure Pmin is set to 0% and the pressure Pmax is set to 100% as described in the above embodiment. Alternatively, the pressure P1 may be set to about atmospheric pressure, and the filling rate may be set to 0% at the pressure P1. Similarly, any pressure P2 between pressures P1 and Pmax may be set to a filling factor of 100%. As a result, although the operating range is limited (see the shaded area in FIG. 2), it is possible to realize operation with high efficiency in the operating range.

1 Compressed air storage power generation device (CAES power generation device)
2 Power generation equipment 10 Compression and expansion combined machine 11 Low pressure port 12 High pressure port 20 Electric power generation combined machine 21 Transmission unit 22 Inverter 30 Pressure storage unit 31 Three-way valve 32 Check valve 33 Pressure sensor 40 Control device 50 Heat exchanger 51 High temperature heat medium tank 52 Low temperature heat medium tank 53 Heat medium pump

Claims (6)

A compression / expansion machine that has a function as a compressor that compresses air and a function as an expander that expands compressed air,
A motor generator that is mechanically connected to the compression / expansion machine and has a function as an electric motor that drives the compression / expansion machine and a function as a generator that is driven by the compression / expansion machine.
A pressure accumulator that is fluidly connected to the compression / expansion machine and stores compressed air generated by the compression / expansion machine.
A transmission unit provided between the compression / expansion combined machine and the motor generator combined machine and having a gear ratio R in the range of the following formula,

Umax: Allowable maximum rotation speed (m / s) or piston allowable peripheral speed (m / s) of the compression / expansion combined machine.
Np: Number of poles of the motor generator
D: Rotor outer diameter (m) or crank rotation diameter (m) of the compression / expansion combined machine
Rmax: Compressed air storage power generator with maximum gear ratio. In the power generation operation in which the motor generator functions as a generator, the compression / expansion machine is set to be driven at the maximum rotation speed or the maximum peripheral speed of the piston when the filling rate of the accumulator is 0%. , The compressed air storage power generation device according to claim 1. The compressed air storage power generation device according to claim 2, wherein the maximum rotational speed or the maximum peripheral speed of the piston is the allowable maximum rotational speed or the allowable peripheral speed of the piston of the compression / expansion combined machine. In the charging operation in which the motor generator functions as an electric motor, the compression / expansion machine is set to be driven at the minimum rotation speed or the minimum peripheral speed of the piston when the filling rate of the accumulator is 100%. The compressed air storage power generation device according to any one of claims 1 to 3. The compressed air storage power generation device according to claim 4, wherein the minimum rotational speed or the minimum peripheral speed of the piston is 0.4 times or more the allowable maximum rotational speed of the compression / expansion combined machine or the allowable peripheral speed of the piston. The compressed air storage power generation device according to any one of claims 1 to 5, wherein the compression / expansion combined machine is a screw type.

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