JP6756880B1 - Compressed air storage power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operation efficiency by favorably cooling a compression / expansion combined machine in a CAES power generation device using a compression / expansion combined machine. SOLUTION: A CAES power generator 1 has a function as a compressor and an expander, and is mechanically connected to a compression / expansion combined machine 10 having a cooling jacket and a compression / expansion combined machine 10. The electric power generator 20 which has the function as an electric motor for driving and the function as a generator driven by the compressor / expansion machine 10 and the compressor / expansion machine 10 are fluidly connected and generated by the compressor / expansion machine 10. The accumulator 30 that stores the compressed air, the coolant pump 51 that adjusts the amount of coolant flowing through the cooling jacket, and the coolant to the cooling jacket when the compressor / expansion machine 10 functions as an expander. It is provided with a control device 40 that controls the coolant pump 51 so that the flow rate of the coolant is equal to or less than the flow rate of the coolant to the cooling jacket when the compression / expansion machine 10 functions as a compressor. [Selection diagram] Fig. 1

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.

In the CAES power generator, the compressor heats up due to the heat of compression in the compression process. Since there is an upper limit to the operating temperature of the compressor, a cooling jacket may be attached to the compressor (see, for example, Patent Document 1). The cooling jacket suppresses the generation of thermal strain in the casing of the compressor during the compression process.

Japanese Unexamined Patent Publication No. 2016-21146

By the way, in the CAES power generation device, both a compressor and an expander are required, and it is preferable to use a compression / expansion combined machine that also serves these. By using the compression / expansion combined machine, the number of components is reduced, the installation area is reduced, the construction man-hours are reduced, and the maintenance cost is reduced.

However, when the compression / expansion combined machine is used, the cooling jacket structure of the compressor as described above cannot be adopted as it is.

An object of the present invention is to improve the operation efficiency of a CAES power generation device using a compression / expansion combined machine by favorably cooling the compression / expansion combined machine.

The present invention has a function as a compressor for compressing air and a function as an expander for expanding compressed air, and has a compression / expansion combined machine having a cooling jacket through which a cooling fluid is passed, and the compression / expansion combined machine. An electric power generator that is mechanically connected and has a function as an electric motor that drives the compressor / expansion machine and a function as a generator that is driven by the compressor / expansion machine, and a compressor / expansion machine fluidly. The accumulator unit that is connected and stores the compressed air generated by the compressor / expansion machine, the liquid flow amount adjusting unit that adjusts the flow rate of the coolant to the cooling jacket, and the compression / expansion machine expand. The amount of the coolant flowing through the cooling jacket when functioning as a machine is equal to or less than the amount of the cooling fluid flowing through the cooling jacket when the compressor / expansion machine functions as a compressor. Provided is a compressed air storage power generation device including a control device for controlling the liquid flow amount adjusting unit.

According to this configuration, by controlling the liquid passing amount adjusting unit by the control device, the compression / expansion combined machine can be sufficiently cooled in the compression process, and excessive cooling of the compression / expansion combined machine in the expansion process can be suppressed. Therefore, since the compression / expansion combined machine can be cooled favorably, the operating efficiency of the CAES power generation device using the compression / expansion combined machine can be improved. Here, it is assumed that the amount of liquid passing through the expansion process includes zero, that is, the flow of liquid is stopped.

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

According to this configuration, the screw rotor is used in both the compression process and the expansion process, and the rotation directions of the screw rotors are opposite to each other in the compression process and the expansion process, so that the compression / expansion machine can be easily used. Can be configured. Further, since the intake amount and the discharge amount can be adjusted by adjusting the rotation speed of the screw rotor, it is possible to provide a CAES power generation device having a wide operating range by being able to responsively follow an irregularly fluctuating input power.

An air supply temperature sensor that measures the temperature of the air supplied to the compression / expansion combined machine may be further provided.

According to this configuration, the supply air temperature sensor can detect an abnormal temperature outside the temperature range allowed in the operation of the compression / expansion combined machine. Here, the air supply means the supply of compressed air to the compression / expansion combined machine in the expansion process. On the other hand, the intake means the suction of air by the compression / expansion combined machine in the compression process.

When the compression / expansion combined machine functions as an expander, when the supply air temperature sensor detects a first abnormal temperature equal to or higher than a predetermined value, the control device controls the liquid flow amount adjusting unit to obtain the above. The amount of the coolant passing through the cooling jacket may be increased.

According to this configuration, it is possible to prevent thermal deformation due to an abnormally high temperature in the expansion process in the compression / expansion combined machine. Here, the abnormal temperature above a predetermined level means a temperature above the operating upper limit of the compression / expansion combined machine.

When the compression / expansion combined machine functions as an expander, when the supply air temperature sensor detects a second abnormal temperature of a predetermined value or less, the control device controls the liquid flow amount adjusting unit to obtain the above. The coolant may be drained from the cooling jacket.

According to this configuration, it is possible to prevent the coolant from freezing due to an abnormally low temperature in the expansion process in the compression / expansion combined machine. Here, the abnormal temperature below a predetermined value means a temperature at which the coolant freezes. The temperature depends on the type of coolant.

According to the present invention, in a CAES power generation device using a compression / expansion combined machine, the compression / expansion combined machine can be suitably cooled by controlling the liquid flow in the cooling jacket according to the operating state, so that the operating efficiency can be improved. ..

The schematic block diagram (compression process) of the compressed air storage power generation apparatus which concerns on embodiment of this invention. The schematic block diagram (expansion process) of the compressed air storage power generation apparatus which concerns on embodiment of this invention. Partial cross-sectional view of the compression / expansion machine (compression process). Partial cross-sectional view (expansion process) of the compression / expansion combined machine. The flowchart which shows the control method of the amount of liquid passing through a cooling jacket. A PV diagram showing the effect of controlling the flow rate.

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

FIGS. 1 and 2 show a compressed air energy storage (CAES) power generation device 1. FIG. 1 shows the CAES power generation device 1 in the charging operation state, and FIG. 2 shows the CAES power generation device 1 in the power generation operation state. Here, the charging operation means to generate and store compressed air by using electric power, and corresponds to the compression process of the compression / expansion combined machine 10 described later. Further, the power generation operation means to generate electric power by using the stored compressed air, and corresponds to the expansion process of the compression / expansion combined machine 10 described later. The thick arrows in FIGS. 1 and 2 indicate the flow of air.

With reference to FIGS. 1 and 2, 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 types of renewable energy are not limited to this, and are constantly or repetitively replenished by natural forces such as sunlight, solar heat, wave power, tidal power, running water, or tide, and fluctuate irregularly. It can cover all power generation using 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.

In the present embodiment, the compression / expansion combined machine 10 is a two-stage type, and includes a low-pressure stage main body 11 and a high-pressure stage main body 12. Therefore, compression and expansion can be performed in two steps each. However, the compression / expansion combined machine 10 may be a single-stage type or a multi-stage type having three or more stages.

Further, the compression / expansion combined machine 10 of the present embodiment is a screw type. Since the screw-type compression / expansion machine 10 can control the rotation speed, it can responsively follow the input power that fluctuates irregularly from the power generation facility 2. 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 in both the compression process and the expansion process and making the rotation directions of the screw rotors opposite to each other in the compression process and the expansion process. However, the compression / expansion combined machine 10 may be a positive displacement type, and may be, for example, a scroll type or a reciprocating type in addition to the screw type.

The flow paths 5a to 5d shown by the broken lines in FIGS. 1 and 2 are the flow paths of the cooling liquid supplied to the cooling jacket described later. As shown in FIGS. 1 and 2, a coolant is supplied to the cooling jacket of the compression / expansion combined machine 10. The flow path 5a is a flow path on the upstream side of the low pressure stage main body 11. The coolant is supplied to the low pressure stage main body 11 through the flow path 5a. The flow path 5b is a flow path from the low pressure stage main body 11 to the high pressure stage main body 12. The coolant flows from the low pressure stage main body 11 to the high pressure stage main body 12 through the flow path 5b. The flow path 5c is a flow path on the downstream side of the high-voltage stage main body 12. The coolant discharged from the high-voltage stage main body 12 is discharged from the CAES power generation device 1 through the flow path 5c. The flow path 5d is a flow path for drainage branched from the flow path 5a, and the details will be described later.

The flow of the cooling liquid in the flow paths 5a to 5d is adjusted by the liquid passing amount adjusting unit 50. In the present embodiment, the liquid flow rate adjusting unit 50 includes a coolant pump 51 for pumping the coolant, a flow rate adjusting valve 52 for adjusting the flow rate, and a three-way valve 53 for draining the liquid. The coolant pump 51, the three-way valve 53, and the flow rate adjusting valve 52 are provided in this order from the upstream side to the downstream side in the flow path 5a.

The coolant pump 51 is a known fluid pump, and its mode is not particularly limited. The coolant pump 51 pumps the coolant from the flow path 5a to the flow path 5c. The pumping of the coolant by the coolant pump 51 is controlled by the control device 40.

The flow rate adjusting valve 52 can adjust the flow rate of the coolant by adjusting the opening degree. The opening degree of the flow rate adjusting valve 52 is controlled by the control device 40.

The three-way valve 53 is a valve for switching between supplying the cooling liquid flowing through the flow path 5a to the compression / expansion combined machine 10 and draining the cooling liquid to the outside through the flow path 5d. The three-way valve 53 is normally set to allow the cooling liquid to flow through the compression / expansion combined machine 10, but when an abnormality described later occurs, the cooling liquid is not supplied to the compression / expansion combined machine 10 and is discharged to the outside through the flow path 5d. It is set to liquid. At the time of this drainage, the cooling liquid remaining in the compression / expansion machine 10 has a higher pressure than the atmospheric pressure, so that the cooling liquid is naturally drained through the flow paths 5b and 5c. ..

The mode of the liquid passing amount adjusting unit 50 is an example, and is not particularly limited to the above configuration, and may be any one that enables adjustment of the liquid passing amount of the cooling liquid.

Further, a flow rate sensor 19 is provided in the flow path 5b. The flow rate sensor 19 can measure the flow rate of the coolant flowing between the low pressure stage main body 11 and the high pressure stage main body 12. The flow rate data measured by the flow rate sensor 19 is sent to the control device 40.

As shown by the alternate long and short dash line in FIGS. 1 and 2, oil is supplied to the compression / expansion combined machine 10. The oil here is supplied to a rotating mechanism such as a bearing of the compression / expansion machine 10. Specifically, the compression / expansion combined machine 10 itself of the present embodiment is an oil-free type that does not require refueling, and the oil here is not supplied to the compression chamber / expansion chamber 11d described later, and the bearing or the like rotates. Supplied to the mechanism. The refueled oil is stored in the oil tank 60 after lubrication of a rotating mechanism such as a bearing. The oil stored in the oil tank 60 is refueled by the oil pump 61 to the rotating mechanism such as the bearing of the compression / expansion machine 10.

FIGS. 3 and 4 show the low pressure stage main body 11 of the compression / expansion combined machine 10. FIG. 3 shows the low pressure stage main body 11 in the charging operation state, and FIG. 4 shows the low pressure stage main body 11 in the power generation operation state. The high-voltage stage main body 12 also has substantially the same structure as the low-pressure stage main body 11.

With reference to FIGS. 3 and 4, the low pressure stage main body 11 has a casing 11c as an exterior. The casing 11c is composed of a plurality of parts and is combined to form one exterior. The casing 11c is provided with a low pressure port 11a that serves as an intake port in the compression process and an exhaust port in the expansion process, and a high pressure port 11b that serves as a discharge port in the compression process and an air supply port in the expansion process. Further, the casing 11c defines a compression chamber / expansion chamber 11d inside. A pair of male and female screw rotors 11f (only the male screw rotor is shown in FIGS. 3 and 4) are arranged in the compression chamber / expansion chamber 11d. The screw rotor 11f is supported by the rotary shaft member 11g. The casing 11c is provided with a through hole 11e, and the rotary shaft member 11g extends through the through hole 11e to the inside and outside of the casing 11c. The through hole 11e of the casing 11c is provided with a sealing mechanism 11i that seals the gap between the rotating shaft member 11g and the casing 11c. The compression chamber / expansion chamber 11d is sealed by the sealing mechanism 11i, so that air leakage from the compression chamber / expansion chamber 11d is suppressed and the lubricating oil that lubricates the bearing 11h does not enter the compression chamber / expansion chamber 11d. It has been done.

Outside the casing 11c, the rotary shaft member 11g is mechanically connected to the motor generator 20 (conceptually illustrated in FIGS. 3 and 4). The rotating shaft member 11g is rotatably supported by the bearing 11h, and can transmit rotational power to the motor generator 20.

The electric power generation combined machine 20 has a function as an electric motor (motor) for driving the compression / expansion combined machine 10 and a function as a generator driven by the compression / expansion combined machine 10. The power generation facility 2 is electrically connected to the motor generator 20. In the charging operation, the motor generator 20 is driven by the fluctuating input power from the power generation facility 2. Further, the motor generator 20 is electrically connected to a power system (not shown). In the power generation operation, the electric power generation combined machine 20 generates power, and the generated power is transmitted to the power system.

The casing 11c also has a function as a cooling jacket. Therefore, the casing may be referred to as a cooling jacket. The cooling jacket 11c is formed with a coolant flow path 11j through which the coolant is passed. The coolant flow path 11j fluidly connects the coolant flow path 5a and the flow path 5b. The coolant can be, for example, water or coolant. The coolant flows in the coolant flow path 11j at a predetermined temperature or lower to cool the casing 11c. Although not shown in detail, the cooling jacket 12c of the high-pressure stage main body 12 has the same structure, and the cooling fluid flow paths formed in the cooling jacket 12c of the high-pressure stage main body 12 are the flow path 5b and the flow path 5c. Is fluidly connected.

With reference to FIGS. 1 and 2, a flow rate adjusting valve 13 is fluidly connected to the low pressure port 11a of the low pressure stage main body 11. The flow rate adjusting valve 13 is a component for adjusting the intake amount and the exhaust amount. In the present embodiment, the flow rate adjusting valve 13 has a configuration in which the flow rate can be adjusted by using the compressed air discharged from the high pressure port 12b of the high pressure stage main body 12. Further, a silencer 14 for reducing intake noise and exhaust noise is fluidly connected to the flow rate adjusting valve 13.

The high pressure port 11b of the low pressure stage main body 11 is fluidly connected to the low pressure port 12a of the high pressure stage main body 12. In FIGS. 1 and 2, the thick arrow A indicates that the arrow A is connected as an air flow path. A heat exchanger 15 is interposed between the high pressure port 11b of the low pressure stage main body 11 and the low pressure port 12a of the high pressure stage main body 12. A heat medium is supplied to the heat exchanger 15, and the heat exchanger 15 exchanges heat between the heat medium and air. Therefore, in the heat exchanger 15, air is heated or cooled by a heat medium as needed.

The high pressure port 12b of the high pressure stage main body 12 is fluidly connected to the pressure accumulator portion 30. A heat exchanger 16 is interposed between the high-voltage port 12b of the high-voltage stage main body 12 and the accumulator portion 30. A heat medium is supplied to the heat exchanger 16, and the heat exchanger 16 exchanges heat between the heat medium and air. Therefore, in the heat exchanger 16, air is heated or cooled by a heat medium as needed.

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.

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

With reference to FIG. 1, when the CAES power generation device 1 performs a charging operation, the motor generator 20 is driven as an electric motor by the input power from the power generation facility 2, and the motor generator 10 is compressed by the motor generator 20. Drive as a machine. That is, in the charging operation, compressed air is generated by using electric power, and the generated compressed air is stored in the accumulator unit 30.

Specifically, in the charging operation, the low-pressure stage main body 11 of the compression / expansion combined machine 10 takes in air from the low-pressure port 11a through the flow rate adjusting valve 13 to compress it, generate compressed air, and discharge the compressed air from the high-pressure port 11b. To do. The compressed air discharged from the high pressure port 11b of the low pressure stage main body 11 is supplied to the low pressure port 12a of the high pressure stage main body 12 after being cooled by the heat exchanger 15. The high-pressure stage main body 12 further compresses the compressed air taken in from the low-pressure port 12a to generate high-pressure compressed air, which is discharged from the high-pressure port 12b. The compressed air discharged from the high-pressure port 12b of the high-pressure stage main body 12 is cooled by the heat exchanger 16 and then stored in the pressure accumulator 30.

With reference to FIG. 2, when the CAES power generation device 1 performs power generation operation, the compressed air supplied from the accumulator unit 30 drives the compression / expansion combined machine 10 as an expander, and the compression / expansion combined machine 10 drives the electric power generation combined machine. 20 is driven as a generator. That is, in the power generation operation, the compressed air of the accumulator 30 is used to generate electric power. In the charging operation and the power generation operation, the rotation directions of the screw rotor 11f (see FIGS. 3 and 4) are opposite to each other.

Specifically, in the power generation operation, the compressed air sent out from the accumulator unit 30 is heated by the heat exchanger 16 and then supplied to the high pressure port 12b of the high pressure stage main body 12 of the compression / expansion combined machine 10. The compressed air supplied to the high-voltage port 12b drives the high-voltage stage main body 12 as an expander, and the motor generator 20 is driven as a generator. The compressed air expanded in the high-pressure stage main body 12 is exhausted from the low-pressure port 12a, heated by the heat exchanger 15, and then supplied to the high-pressure port 11b of the low-pressure stage main body 11. The compressed air supplied to the high-voltage port 11b drives the low-voltage stage main body 11 as an expander, and the motor generator 20 is driven as a generator. The air expanded in the low pressure stage main body 11 is exhausted from the low pressure port 11a and released to the atmosphere. The electric power generated by the motor generator 20 is supplied to an electric power system (not shown).

An air supply temperature sensor 17 is installed at the high pressure port 11b of the low pressure stage main body 11, and a supply air temperature sensor 18 is similarly installed at the high pressure port 12b of the high pressure stage main body 12. The air supply temperature sensors 17 and 18 can measure the temperature of the compressed air supplied to the low pressure stage main body 11 and the high pressure stage main body 12 in the expansion process, respectively. The temperature data measured by the supply air temperature sensors 17 and 18 is sent to the control device 40 and used for the control described later.

A method of controlling the liquid passage amount adjusting unit 50 by the control device 40 will be described with reference to FIG.

When the operating state of the CAES power generation device 1 is charging (charging: step S2), the control device 40 controls the liquid passing amount adjusting unit 50 to set the liquid passing amount V ₀ (step 3). The liquid passing amount V ₀ here is a liquid passing amount that allows efficient compression when the compression / expansion combined machine 10 is driven as a compressor. Further, the control unit 40, when the operating state of the CAES power generator 1 is a generator operation (power: step S2), and a liquid passing amount _{V 1} by controlling the liquid passing amount adjusting unit 50 (Step 4). The liquid passage amount V ₁ here may be, for example, a liquid passage amount such that the coolant does not boil in the cooling jacket, or the liquid passage may be completely stopped.

In other words, the control unit 40, the cooling jacket 11c when compression-expansion combined machine 10 functions as an expander, the liquid permeation amount V ₁ of the coolant to 12c, when the compression and expansion combined machine 10 functions as a compressor The liquid passing amount adjusting unit 50 is controlled so that the liquid passing amount V ₀ or less of the cooling liquid to the cooling jackets 11c and 12c of the above. Controller 40 is preferably the cooling jacket 11c when compression-expansion combined machine 10 functions as an expander, the liquid permeation amount V ₁ of the coolant to 12c, the compression-expansion combined machine 10 functions as a compressor The liquid passing amount adjusting unit 50 is controlled so that the liquid passing amount of the cooling liquid to the cooling jackets 11c and 12c is less than V ₀ . For example, the liquid passing amount V ₁ in the power generation operation may be set to about 1/10 of the liquid passing amount V _{0 in} the charging operation. Such control of the flow rate may be performed based on the feedback of the flow rate sensor 19. This also applies to the subsequent control of the flow rate.

Controller 40, even after the liquid passing amount V ₁ at step S4, whether the temperature of the compressed air supply to the compressor-expander combined machine 10 is not the abnormal high temperature (first abnormal temperature) It is monitored by the measured values of the supply air temperature sensors 17 and 18 (step S5). When the abnormally high temperature is detected: The (YES step S5), and the passing liquid amount _{V 2} (step S6). Here, the abnormally high temperature means a temperature exceeding the operating upper limit temperature of the compression / expansion combined machine 10. For example, the liquid passing amount V ₂ here may be the same as the liquid passing amount V ₀ during the charging operation. Here, the magnitude relationship of the liquid passing volumes V ₀ , V ₁ , and V ₂ is V ₁ ≤ V ₂ ≤ V ₀ . Further, when the values of the supply air temperature sensors 17 and 18 are not abnormally high (NO: step S5), the control device 40 has an abnormally low temperature of the supply air temperature sensors 17 and 18. Monitor for presence (step S7). When the values of the supply air temperature sensors 17 and 18 are abnormally low temperature (second abnormal temperature) (YES: step S7), the cooling liquid is drained from the cooling jackets 11c and 12c (step S8). .. Here, the abnormally low temperature means the temperature at which the coolant freezes. The abnormally low temperature is a temperature that differs depending on the type of coolant. At the time of drainage, the three-way valve 53 (see FIGS. 1 and 2) is switched to drain the coolant to the outside through the flow path 5d without flowing the coolant through the compression / expansion machine 10. Then, after completing these processes, the control ends (step S9). In practice, these controls are constantly repeated during the operation of the CAES generator 1.

According to the CAES power generation device 1, the following effects are obtained.

By controlling the liquid flow amount adjusting unit 50 by the control device 40, the compression / expansion combined machine 10 can be sufficiently cooled in the charging operation (compression process), and the compression / expansion combined machine 10 is excessively cooled in the power generation operation (expansion process). Can be suppressed. Therefore, since the compression / expansion combined machine 10 can be cooled favorably, the operating efficiency of the CAES power generation device 1 using the compression / expansion combined machine 10 can be improved.

FIG. 6 is a PV diagram simply showing the effect of controlling the flow rate. That is, the vertical axis represents the pressure P of air, and the horizontal axis represents the volume V of air. FIG. 6 is a schematic diagram for explaining the effect. In this embodiment, the two-stage compression / expansion machine 10 is used, but in FIG. 6, the single-stage compression / expansion machine 10 is used. Is shown.

With reference to FIG. 6, points X1 to X21 or points X22 indicate an air supply stroke, and in the air supply stroke, compressed air is supplied from the accumulator 30 to the compression / expansion combined machine 10. Next, at the point X21 or the point X22 to the point X3 (atmospheric pressure), the expansion stroke is shown, and the compressed air is expanded in the expansion stroke. In FIG. 6, two straight lines L1 and L2 corresponding to the air supply stroke and two curves C1 and C2 corresponding to the expansion stroke are shown. The straight line L1 and the curve C1 show a case where the flow rate is not controlled, unlike the present embodiment. The straight line L2 and the curve C2 show a case where the liquid flow amount is controlled as in the present embodiment and the liquid flow amount in the expansion process (air supply stroke and expansion stroke) is set to be equal to or less than the liquid flow amount in the compression process.

With reference to FIG. 6, when the liquid flow rate is controlled (straight line L2, curve C2), the area portion S1 shown by the diagonal line is higher than when the liquid flow rate is not controlled (straight line L1, curve C1). It can be confirmed that the workload is increased only in S2. Therefore, when the liquid flow rate is controlled as in the present embodiment (straight line L2, curve C2), the operation efficiency is improved as compared with the case where the liquid flow rate is not controlled (straight line L1, curve C1). You can see that.

Specifically, heat exchange by passing liquid through the cooling jackets 11c and 12c is divided into the following two types.
1) Between the external air supply port 11b-1 and the internal air supply port 11b-2, which is the air supply process (see FIG. 4).
2) Between the internal air supply port 11b-2 and the internal exhaust port 11a-1 (expansion chamber 11d), which is the expansion stroke (see FIG. 4).

With reference to FIG. 6, the shaded area S1 can be obtained by limiting the amount of heat released in the air supply stroke of 1), and the shaded region S2 can be obtained by limiting the amount of heat released in the expansion stroke of 2). .. The increase in the shaded area S1 in 1) indicates that heat dissipation from the external air supply port 11b-1 to the internal air supply port 11b-2 causes a decrease in the supply air temperature, which can be suppressed. Regarding the decrease in the supply air temperature from the external air supply port 11b-1 to the internal air supply port 11b-2, since the internal air supply volume is constant, the mass of supply air required for expansion increases as this temperature decreases. The flow rate [kg / h] increases. Therefore, since the specific power generation amount [kWh / kg] indicating the power generation performance is lowered, it is necessary to suppress the liquid flow amount in order to limit the heat dissipation. The increase in the shaded area S2 in 2) indicates that the expansion efficiency is improved by enabling expansion at a high temperature.

Further, in the present embodiment, the supply air temperature sensors 17 and 18 detect an abnormal supply air temperature to the compression / expansion combined machine 10, and the amount of liquid flowing is suitably controlled as described above. Therefore, in the compression / expansion combined machine 10, thermal deformation of the casings 11c and 12c due to an abnormally high temperature in the expansion process can be prevented, and freezing of the coolant in the casings 11c and 12c due to an abnormally low temperature in the expansion process can be prevented. The supply air temperature sensors 17 and 18 and the control of the amount of liquid passing therethrough are not essential and may be omitted if necessary.

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.

1 Compressed air storage power generation device (CAES power generation device)
2 Power generation equipment 5a to 5d Flow path 10 Compression / expansion combined machine 11 Low pressure stage body 11a Low pressure port 11a-1 Internal exhaust port 11b High pressure port 11b-1 External air supply port 11b-2 Internal air supply port 11c Casing (cooling jacket)
11d Compression chamber / expansion chamber 11e Through hole 11f Screw rotor 11g Rotating shaft member 11h Bearing 11i Seal mechanism 11j Coolant flow path 12 High pressure stage body 12a Low pressure port 12b High pressure port 12c Casing (cooling jacket)
13 Flow control valve 14 Silencer 15, 16 Heat exchanger 17, 18 Air supply temperature sensor 19 Flow sensor 20 Electric power generation combined machine 30 Pressure accumulator 40 Control device 50 Liquid flow rate adjustment unit 51 Coolant pump 52 Flow control valve 53 Three-way valve 60 Oil tank 61 Oil pump

Claims (5)

A compression / expansion machine that has a function as a compressor that compresses air and an expander that expands compressed air, and has a cooling jacket that allows the coolant to pass through.
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 liquid flow adjusting unit that adjusts the flow rate of the coolant to the cooling jacket,
The amount of the coolant flowing through the cooling jacket when the compression / expansion combined machine functions as an expander is the flow of the coolant through the cooling jacket when the compression / expansion combined machine functions as a compressor. A compressed air storage power generation device including a control device that controls the liquid flow amount adjusting unit so that the amount of liquid is equal to or less than the liquid amount. The compressed air storage power generation device according to claim 1, wherein the compression / expansion combined machine is a screw type. The compressed air storage power generation device according to claim 1 or 2, further comprising a supply air temperature sensor for measuring the temperature of air supplied to the compression / expansion combined machine. When the compression / expansion combined machine functions as an expander, when the air supply temperature sensor detects a first abnormal temperature equal to or higher than a predetermined value, the control device controls the liquid flow amount adjusting unit to obtain the above. The compressed air storage power generation device according to claim 3, which increases the amount of the coolant passing through the cooling jacket. When the compression / expansion combined machine functions as an expander, when the supply air temperature sensor detects a second abnormal temperature of a predetermined value or less, the control device controls the liquid flow amount adjusting unit to obtain the above. The compressed air storage power generation device according to claim 3 or 4, wherein the cooling liquid is drained from the cooling jacket.

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