JP2008032234A - Compressor and heat pump device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expander integrated compressor for obtaining consistently high operating efficiency by reducing bypass pipe lines and embodying valve control to maximize power recovery from a high-pressure operating fluid while eliminating operating conditions (constraints) that "a density ratio is constant". <P>SOLUTION: The compressor comprises a compressor part 12 for compressing the operating fluid sucked into a compression chamber 13 by the rotation of a driving shaft 14, and an expander part 20 for expanding the operating fluid sucked into an expansion chamber 25 to obtain the rotating power of a power recovery shaft 26. There are provided a discharge pressure sensor 48 for detecting the discharge pressure of a discharge chamber 33 and a solenoid valve 40 for controlling the communication of a suction hole 27 with the expansion chamber 25. Opening/closing timing for the solenoid valve 40 is varied so that the amount of the operating fluid introduced into the expansion chamber 25 reaches a target amount which is found from discharge pressure obtained by the discharge pressure sensor 48 and target suction pressure for maximizing refrigerating cycle efficiency. Thus, consistently high operating efficiency can be obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an expander-integrated compressor connected to an expander that supplies rotational pressure by supplying a high-pressure working fluid.

FIG. 5 shows a system configuration of a conventional general power recovery type air conditioner. In FIG. 5, this system includes a condenser 101, an evaporator 102, a compressor 103, and an expander 104. The compressor 103 compresses the working fluid and an expander that generates rotational power from the high-pressure working fluid. 104 is connected to the motor 105 in one axis. That is, the expander 104 is configured to generate rotational power by ideally entropy expansion of the high-pressure working fluid and directly assist the driving power of the compressor 103. The reason why the compressor 103 and the expander 104 are connected to each other in this manner is that the structure is simple and the power recovery loss is small.
FIG. 6 shows how the refrigeration cycle changes when the working fluid is carbon dioxide in such a conventional air conditioner. In the Mollier diagram (ph diagram) in FIG. 6, 1 → 2 is a compression process in which the working fluid is compressed and boosted from the low pressure P1 to the high pressure Ph in the compressor 103, 2 → 3 is the condenser 101, etc. The pressure release process 3 → 4 indicates an expansion process in which the working fluid is expanded from the high pressure Ph to the low pressure Pl in the expander 104 to recover the power, and 4 → 1 indicates an isobaric heat absorption process in the evaporator 102.
However, in the above configuration in which the compressor 103 and the expander 104 are connected to one shaft, the compressor 103 and the expander 104 always rotate at the same rotation speed, and therefore the system is operated with a constant refrigerant circulation amount. The operating condition (constraint) of the working fluid “density ratio = constant” occurs, for example, it is difficult to appropriately control the discharge pressure (high pressure Ph) of the compressor 103 that affects the efficiency of the system. For the reason, high-efficiency operation cannot always be realized.
Thus, as a technique for eliminating such an operation condition (constraint) of “density ratio = constant”, there is a known technique described in Patent Document 1. FIG. 7 shows a system configuration of another conventional air conditioner. In the present air conditioner, a bypass pipe 112 is provided between the discharge pipe 110 and the suction pipe 111 of the expander 104 so as to communicate the both, and the control valve for adjusting the passage area to the bypass pipe 112 is increased or decreased. 106 is provided.
The air conditioner having such a configuration performs the following operations.
A target value of the discharge temperature of the compressor 103 is set, and then the opening degree of the control valve 106 is controlled so that the discharge temperature of the compressor 103 becomes the target value. When the control valve 106 is controlled in the closing direction, the amount of working fluid passing through the bypass line 112 decreases, and the amount of working fluid entering the expander 104 increases. Conversely, when the control valve 106 is controlled to open, the amount of working fluid that passes through the bypass line 112 increases, and the amount of working fluid that enters the expander 104 decreases. By controlling the opening degree of the control valve 106 in this way, the operating conditions of the system can be freely determined so as to obtain high operating efficiency while using the expander 104.
As another technique for eliminating the operation condition (constraint) of “density ratio = constant”, there is a known technique described in Patent Document 2. In this technique, the pressure after expansion of the working fluid is reduced under the operating conditions where the ratio between the high pressure and the low pressure of the system (pressure ratio) is smaller than the pressure ratio assumed during the design of the expander. It is lower than the pressure and prevents the power recovery amount from decreasing (loss due to overexpansion). That is, the communication passage is branched from the working fluid inflow side of the expander and communicates with the suction / expansion process position of the expander, and a valve for controlling the passage of the working fluid is provided in the communication passage. When the conditions arise, the valve is opened to allow a part of the working fluid to flow into the expander, the amount of working fluid entering the expander is increased, and the pressure of the working fluid after expansion is increased.
JP 2001-116371 A JP 2004-197640 A

  However, in the technique of Patent Document 1, power recovery cannot be performed for the working fluid passing through the bypass pipe, and the potential energy of the high-pressure working fluid is unconditionally discarded. Further, although the technique of Patent Document 2 is configured to prevent the occurrence of overexpansion, there is no description of a specific valve control method for realizing it.

  Accordingly, the present invention solves the above-described conventional problems, and provides an expander-integrated compressor that embodies valve control, maximizes power recovery from a high-pressure working fluid, and always obtains high operating efficiency. For the purpose.

The compressor of the present invention according to claim 1 has a compression chamber and a drive shaft, and compresses the working fluid sucked into the compression chamber by rotating the drive shaft, an expansion chamber, A suction hole that guides the working fluid to the expansion chamber with an expander suction pressure; a discharge hole that discharges the working fluid from the expansion chamber; and a power recovery shaft connected to the drive shaft. A pressure detecting means for detecting an expander discharge pressure of the working fluid discharged from the discharge hole, the compressor including an expander unit that obtains rotational power of the power recovery shaft by expanding the sucked working fluid And a suction valve in the suction hole, and the amount of working fluid guided from the suction hole to the expansion chamber is obtained by the pressure detection means for maximizing the expander discharge pressure and the refrigeration cycle efficiency. Wherein as the target amount obtained from an expander suction pressure to target, characterized in that the arrangement for varying the opening and closing timing of the intake valve.
According to a second aspect of the present invention, in the compressor according to the first aspect, a suction temperature sensor for measuring a suction temperature of the working fluid sucked into the suction hole, and a discharge of the working fluid discharged from the discharge hole. A discharge temperature sensor for measuring temperature is provided, and the target expander suction pressure is calculated from the suction temperature and the discharge temperature.
According to a third aspect of the present invention, in the compressor according to the second aspect, the pressure detecting means converts the discharge temperature measured by the discharge temperature sensor to obtain the expander discharge pressure. It is characterized by that.
According to a fourth aspect of the present invention, in the compressor according to any one of the first to third aspects, the suction valve is an electromagnetic valve.
According to a fifth aspect of the present invention, in the compressor according to any one of the first to fourth aspects, the opening timing for opening the suction valve from the closed state to the open timing is the start of suction at which the volume of the expansion chamber is minimized. It is characterized by having a control function that sets the closing timing for opening and closing the suction valve from the opening start time to the time when the volume of the expansion chamber becomes maximum.
According to a sixth aspect of the present invention, in the compressor according to any one of the first to fifth aspects, the working fluid state is maintained to maintain the relationship between the volume of the working fluid and the pressure when expanding in the expansion chamber. And the target amount is obtained using the relationship between the volume and pressure of the working fluid held by the working fluid state holding unit.
A seventh aspect of the present invention is the compressor according to any one of the first to sixth aspects, wherein the compressor is operated using a working fluid that expands from a supercritical phase to a liquid phase or a gas-liquid two phase. And
The present invention according to claim 8 is characterized in that the compressor according to any one of claims 1 to 7 is operated using a working fluid mainly composed of carbon dioxide.
According to a ninth aspect of the present invention, in the heat pump device of the present invention, the amount of working fluid guided to the expansion chamber by controlling the opening / closing timing of the suction valve can be set to the target amount that maximizes the refrigeration cycle efficiency. The compressor according to claim 8 is used.

  According to the compressor of the present invention and the heat pump device using the compressor, the amount of working fluid guided to the expansion chamber by controlling the opening / closing timing of the suction valve can be set to a target amount that provides high operating efficiency. By reducing the number of passages and realizing valve control, eliminating the operating conditions (constraints) of “density ratio = constant”, the maximum power recovery from high-pressure working fluid can be achieved, and high operating efficiency can always be obtained. it can.

The compressor according to the first embodiment of the present invention has a compression chamber and a drive shaft, and compresses the working fluid sucked into the compression chamber by rotating the drive shaft, an expansion chamber, The working fluid has a suction hole for introducing the working fluid into the expansion chamber with the suction pressure of the expander, a discharge hole for discharging the working fluid from the expansion chamber, and a power recovery shaft connected to the drive shaft, and is sucked into the expansion chamber. A compressor including an expander unit that obtains rotational power of the power recovery shaft by expanding the pressure, a pressure detection means for detecting the expander discharge pressure of the working fluid discharged from the discharge hole, and a suction valve in the suction hole; The amount of working fluid guided from the suction hole to the expansion chamber is set to the target amount obtained from the expander discharge pressure obtained by the pressure detection means and the target expander suction pressure for maximizing the refrigeration cycle efficiency. You As, in which a configuration for varying the opening and closing timing of the intake valve. According to this embodiment, it is possible to always obtain high operating efficiency by varying the opening / closing timing of the suction valve so that the volume of the expansion chamber capable of sucking the working fluid is an ideal volume. An expander-integrated compressor is provided.
In the compressor according to the first embodiment, the second embodiment of the present invention includes a suction temperature sensor that measures the suction temperature of the working fluid sucked into the suction hole, and a working fluid discharged from the discharge hole. A discharge temperature sensor for measuring the discharge temperature is provided, and a target expander suction pressure is calculated from the suction temperature and the discharge temperature. According to the present embodiment, the target suction pressure that maximizes the refrigeration cycle efficiency can be obtained by calculation.
In the compressor according to the second embodiment, the third embodiment of the present invention is configured such that the pressure detecting means converts the discharge temperature measured by the discharge temperature sensor to obtain the expander discharge pressure in the compressor according to the second embodiment. Is. According to the present embodiment, it can be linked to cost reduction.
In the fourth embodiment of the present invention, in the compressors according to the first to third embodiments, the suction valve is an electromagnetic valve. According to the present embodiment, the opening / closing timing can be easily measured, and the non-expanding problem can be prevented.
In the fifth embodiment of the present invention, in the compressors according to the first to fourth embodiments, the opening timing for opening the intake valve from the closed state is set as the intake start time at which the volume of the expansion chamber is minimized, In this configuration, the closing timing for opening the valve from closing to closing is the time from the suction start time to the maximum expansion chamber volume. According to the present embodiment, the brake loss can be minimized, and the volume of the expansion chamber into which the working fluid is introduced can be set to an ideal volume.
According to a sixth embodiment of the present invention, in the compressor according to the first to fifth embodiments, a working fluid state holding unit that holds the relationship between the volume and pressure of the working fluid when expanding in the expansion chamber. The target amount is obtained by using the relationship between the volume of the working fluid held by the working fluid state holding unit and the pressure. According to the present embodiment, the relationship between the volume of the working fluid and the pressure can be an approximate expression of a practical expansion process, for example, and higher operating efficiency can be obtained.
In the seventh embodiment of the present invention, the compressors according to the first to sixth embodiments are operated using a working fluid that expands from a supercritical phase to a liquid phase or a gas-liquid two phase.
In the eighth embodiment of the present invention, the compressors according to the first to seventh embodiments are operated using a working fluid mainly composed of carbon dioxide.
The heat pump device according to the ninth embodiment of the present invention can control the opening / closing timing of the intake valve to set the amount of working fluid guided to the expansion chamber to a target amount that maximizes the refrigeration cycle efficiency. The compressor according to any one of claims 8 to 8 is used. According to the present embodiment, the operation efficiency of the heat pump device can be constantly increased.

FIG. 1 is a longitudinal sectional view of a compressor according to an embodiment of the present invention, and FIG. 2 is a transverse sectional view of an expander section in the compressor according to the present embodiment. 1 and 2 show a rotary vane type compressor and an expander, but the method of the compressor and the expander is not limited to this, and any type such as a rotary type, a reciprocating type, and a scroll type may be used. As the working fluid, a working fluid that expands from a supercritical phase to a liquid phase or a gas-liquid two phase, for example, a working fluid mainly composed of carbon dioxide is used.
In FIG. 1, the compressor according to the present embodiment is configured to include a compressor unit 12, an electric motor unit 16, an expander unit 20, and a control unit inside a sealed container 10. Note that the control unit is not restricted to the inside or outside of the sealed container 10.
The compressor unit 12 includes a compression chamber 13, a drive shaft 14, and a rotor 15, and compresses the working fluid sucked into the compression chamber 13 from a low pressure to a high pressure by rotating the drive shaft 14 and the rotor 15. . The electric motor unit 16 includes a stator 17 and a rotor 18, and the rotor 18 is fixed to the drive shaft 14. The expander unit 20 includes a cylinder 21, a rotor 23, and a power recovery shaft 26 (hereinafter referred to as a shaft 26). The expander unit 20 sucks a working fluid through a suction path 32 and a suction hole 27. In the working chamber 25 as an expansion chamber to be formed, the shaft 26 is expanded from a high pressure to a low pressure, and discharged from the working chamber 25 through the discharge chamber 33 and the discharge passage 34 to obtain rotational power for the shaft 26. This rotational power is transmitted from the shaft 26 to the drive shaft 14 and is collected as the drive force of the compressor unit 12.

2, the expander unit 20 includes a cylinder 21, a rotor 23, four vanes 24, a shaft 26, a cover 31, a suction pipe 35, and an electromagnetic valve 40.
That is, the cylinder 21 has a cylindrical inner wall 21a, and side plates 21b and 21c (see FIG. 1) are provided at both ends thereof. A cylindrical rotor 23 is disposed inside the cylinder 21, and a part of the outer periphery of the rotor 23 forms a small gap 22 with the inner wall 21 a of the cylinder 21. The inner wall 21 a and the outer periphery of the rotor 23 are in contact with each other at the base point (contact point) of the small gap 22.
The rotor 23 is provided with four grooves 23a perpendicular to the upper and lower end surfaces at a pitch of 90 deg. Each vane 24 is slidably inserted into each groove 23 a, and the tip of the vane 24 is in contact with the inner wall 21 a of the cylinder 21.
The working chamber 25 is formed as spaces 25a, 25b, 25c, 25d, and 25e surrounded by the inner wall 21a of the cylinder 21, the rotor 23, and the vanes 24. The shaft 26 is formed integrally with the rotor 23, is rotatably supported on the side plates 21 b and 21 c, and is connected to the drive shaft 14 of the compressor unit 12.

In addition, the cylinder 21 is provided with a suction hole 27 through which the working fluid flows into the working chamber 25 and a discharge hole 28 through which the working fluid flows out from the working chamber 25. Further, an electromagnetic valve 40 is disposed between the expansion chamber 25 (25a) and the suction hole 27.
In the vicinity of the discharge hole 28, an opening 28 a that is opened in a range in the circumferential direction of the inner wall 21 a of the cylinder 21 is provided. The range in which the opening 28a is provided starts from a starting position 28b of {180 × (1 + 1 / n)} deg from the base point of the small gap 22 in the rotation direction indicated by the arrow of the shaft 26, where n is the number of vanes 24, This is a range that ends at the end position 28 c in the vicinity of the small gap 22. The start position 28b of the opening 28a in FIG. 2 is a position of 225 deg because there are four vanes 24.
Further, a cover 31 is provided on the side of the cylinder 21, a suction pipe 35 is inserted into the cover 31, and a suction path 32 that guides the working fluid to the suction hole 27 is formed inside the suction pipe 35. Yes. As shown in FIG. 1, a discharge chamber 33 for temporarily storing the working fluid flowing out from the discharge hole 28 is formed inside the sealed container 10, and inside the discharge pipe 36 joined to the sealed container 10, A discharge path 34 is formed through which the working fluid flows out from the discharge chamber 33.

Further, the configuration of the control unit will be described.
As shown in FIG. 1, the control unit includes a discharge pressure sensor 48, a suction temperature sensor 50, a discharge temperature sensor 51, a solenoid valve control unit 60, and a working fluid state holding unit 61.
In other words, the solenoid valve 40 is energized via the solenoid valve control unit 60 and the solenoid valve 40 is electrically opened and closed to control the communication between the expansion chamber 25 and the suction hole 27. By the way, it is desirable that the solenoid valve 40 be normally opened and closed when energized (controlled) assuming an electrical trouble. The reason for this is that if it is a solenoid valve, it is possible to easily control the opening and closing of the valve (measure the timing of opening and closing), and if it is a normally open solenoid valve that does not close even if an electrical trouble occurs, This is because a non-inflating adverse effect of not functioning as an expander is prevented.
The suction temperature sensor 50 measures the temperature of the working fluid in the suction path 32 or the suction hole 27 as the suction temperature Tb of the expander. The discharge pressure sensor 48 and the discharge temperature sensor 51 measure the pressure and temperature of the working fluid in the discharge chamber 33 or the discharge path 34 as the discharge pressure Pc and the discharge temperature Tc of the expander. The temperature sensor and the pressure sensor may be anything as long as they can measure the temperature and pressure of the working fluid. Further, the suction temperature Tb of the expander is measured between the condenser (see FIG. 5) and the suction pipe 35, and the discharge pressure Pc and discharge of the expander are discharged between the discharge pipe 36 and the evaporator (see FIG. 5). A configuration for measuring the temperature Tc is also possible.
The electromagnetic valve control unit 60 controls the opening and closing of the electromagnetic valve 40. The working fluid state holding unit 61 is a part that holds data or an approximate expression indicating the relationship between the volume and pressure of the working fluid when the working fluid expands in the expansion chamber 25, and uses, for example, a semiconductor memory or the like. It is configured. The working fluid state holding unit 61 may be integrated with the electromagnetic valve control unit 60.

Next, the operation of the expander section in the compressor of the present embodiment having the above configuration will be described first in the basic case where the electromagnetic valve 40 is normally open. FIG. 3 is a PV diagram of the working chamber when the solenoid valve in the present embodiment is normally open, that is, a PV diagram of the working chamber 25 of the expander unit 20. In addition, description of the compressor part which is not related to the characteristic of this invention is abbreviate | omitted.
The working chamber 25 is generated in the space 25 a on the suction hole 27 side of the small gap 22. Thereafter, the process of sucking the working fluid having the suction pressure Pb corresponding to the high pressure Ph of the refrigeration cycle from the suction hole 27 while increasing the volume with the rotation of the rotor 23, that is, the suction process is performed. The inhalation process corresponds to AB in FIG.
When the working chamber 25 reaches the position of the space 25b, the communication with the suction hole 27 is cut off to become a sealed space, and then the volume increases with the rotation of the rotor 23, and the pressure of the working fluid inside decreases. The process, that is, the expansion process is performed. The expansion process corresponds to BC in FIG.
The working chamber 25 has a maximum volume at the position of the space 25c. This time corresponds to C in FIG. 3, and the discharge pressure of the working chamber 25 is Pc. The moment the rotor 23 rotates slightly from here, the working chamber 25 located in the space 25c communicates with the discharge hole 28 through the opening 28a, and the working fluid is pushed out of the working chamber 25 to the discharge chamber 33. Here, when the discharge pressure Pc of the working chamber 25 in C is equal to the low-pressure pressure Pl of the refrigeration cycle, the decompressed working fluid is discharged smoothly, and the volume of the working chamber 25 decreases with the low-pressure pressure Pl. That is, a discharge process for shifting from C to D in FIG. 3 is performed.
Thereafter, the working chamber 25 communicates with the suction hole 27 again and returns to the state of A in FIG.

  However, in actuality, the low-pressure pressure Pl of the refrigeration cycle varies depending on the heat exchange conditions in the evaporator (see FIG. 5), the operating conditions of the refrigeration cycle, and the like. In the operation of the expander described above, the ratio of the volume at the moment when the working fluid is sealed (space 25b in FIG. 2) and the volume immediately before the working fluid is discharged (space 25c in FIG. 2), that is, the expansion ratio is constant. For this reason, when the low pressure P1 fluctuates, it cannot be made equal to the discharge pressure Pc of the expander. Therefore, in this embodiment, the operation of changing the amount of the working fluid sucked into the working chamber 25 using the electromagnetic valve 40 and performing control so that the discharge pressure Pc of the expander is equal to the low pressure Pl of the refrigeration cycle is performed. Is called.

Next, the opening / closing operation of the electromagnetic valve 40 will be described.
FIG. 4 shows the relationship between the opening / closing timing of the electromagnetic valve 40 in this embodiment and the flow rate of the working fluid entering the working chamber 25 during the suction process. Here, the time when the electromagnetic valve 40 is opened from the closed time is expressed as time Top, and the time when the electromagnetic valve 40 is opened from closed is expressed as time Tcl.
First, the solenoid valve 40 is controlled to be opened immediately before the working chamber 25 communicates with the suction hole 27. If the electromagnetic valve 40 is kept closed at this time, the working chamber 25 is evacuated as it rotates, and a loss of braking the rotation of the rotor 23 is not preferable. That is, the brake loss is minimized by a configuration having a control function that sets the opening timing (that is, the time Top) at which the solenoid valve 40 is opened from the closed state to the suction start time at which the volume of the working chamber 25 is minimized. Can do.
Next, from time Top, the working chamber 25 communicates with the suction hole 27 and the working fluid is sucked into the working chamber 25. Then, the electromagnetic valve 40 is closed at a previous time Tcl at which the working chamber 25 reaches the maximum volume Vb that can be sucked. As a result, the working fluid is sucked into the volume Vb ′ smaller than the maximum volume Vb. By changing the timing of the time Tcl for closing the electromagnetic valve 40 in this way, the magnitude of Vb ′ is varied. In other words, by a configuration having a control function that sets the closing timing (that is, the time Tcl) at which the electromagnetic valve 40 is closed from the opening to the time from the suction start time to the maximum volume of the working chamber 25. The working fluid suction amount can be varied.

Next, a method for determining the time Tcl for closing the electromagnetic valve 40 will be described.
When an air conditioner using carbon dioxide as a working fluid is considered, the efficiency of the refrigeration cycle and the high pressure Ph have a relationship that maximizes the efficiency at a certain high pressure. S. M.M. According to Mr. Liao, a high pressure at which the refrigeration cycle efficiency is maximized (hereinafter referred to as the optimum pressure Popt) can be expressed by the following equation.
Popt = (2.778−0.0157 × te) tg + (0.381 × te−9.34)
(Formula 1)
Here, te is the evaporator temperature (that is, the temperature corresponding to the discharge temperature Tc of the expander), tg is the condenser outlet temperature (that is, the temperature corresponding to the suction temperature Tb of the expander), and each temperature is the discharge temperature. It can be measured by the sensor 51 and the suction temperature sensor 50. Then, the target expander suction pressure Popt can be calculated from the suction temperature Tb and the discharge temperature Tc using Formula 1.
Therefore, the refrigeration cycle is operated such that the high-pressure pressure Ph, that is, the suction pressure Pb of the expander corresponding to the high-pressure pressure Ph becomes the optimum pressure Popt as the target expander suction pressure. Can be said to be desirable.

By the way, since the working fluid of the present embodiment is in a gas-liquid two-phase state at the evaporator temperature te, based on the evaporator temperature te, it is converted from the relationship between the saturation pressure and temperature of the working fluid, The low-pressure pressure Pl (evaporator pressure) of the refrigeration cycle, that is, the discharge pressure Pc of the expander corresponding to the low-pressure pressure Pl can be known. In other words, even if the discharge pressure sensor 48 is not provided, a configuration in which the discharge temperature Tc measured by the discharge temperature sensor 51 is converted to obtain the expander discharge pressure Pc can be obtained, which leads to cost reduction.
Further, the volume Vc of the working chamber 25 in the final state C (the space 25c in FIG. 3) of the expansion process of the expander (curve BC in FIG. 3) is also known from the design specifications. Therefore, if the relationship between the volume of the working chamber 25 and the pressure is known, the target volume Vbo ′ of the expansion chamber for sucking the working fluid is determined by following the reverse state transition from the final state C to the initial state B of the expansion process. can do.
For example, if the working fluid is an ideal gas and there is no leakage, friction, or heat in / out during the expansion process, and an ideal isentropic change is performed, the relationship between the volume of the working chamber 25 and the pressure is expressed by the following equation. Is done.
PV ^κ = (constant) (Formula 2)
However, (kappa) is a specific heat ratio.
In order to make the suction pressure Pb the target optimum pressure Popt in the initial state B of the expansion process by using the mathematical formula 2, the low pressure pressure Pl in the final state C (that is, the detected discharge pressure Pc), the working chamber volume From Vc (known from the design specification), Vbo ′ represented by the following equation is the target volume to be set in B, that is, the working fluid suction amount.
Vbo ′ = (Pl / Popt) ^{1 / κ} · Vc (Formula 3)
Then, the timing of the time Tcl for closing the electromagnetic valve 40 is determined using this Vbo ′.
In other words, the target expander suction pressure that maximizes the refrigeration cycle efficiency calculated from the expander discharge pressure Pc (that is, the low pressure P1), the suction temperature Tb, and the discharge temperature Tc is set to the amount of the working fluid guided to the expansion chamber. The time Tcl is determined so as to obtain a target amount obtained from Popt. An example of a method for determining the time Tcl from the target volume Vbo ′ is as follows. The expansion angle θb (known from the design specifications) of the expander from the base point to the maximum volume Vb is multiplied by the ratio of Vbo ′ and Vb (known from the design specifications) to obtain the target volume Vbo ′ from the base point. The rotation angle θbo is obtained. Then, the rotational speed of the expander and the rotational angle θx from the base point of the small gap 22 are detected, and the time when the rotational angle θx reaches the rotational angle θbo is defined as time Tcl, and the electromagnetic valve 40 is closed.

By the way, in the actual expansion process BC, the working fluid cannot be treated as an ideal gas in which the relationship between the volume and the pressure when expanding is expressed by Formula 2. Transition to a gas-liquid two-phase state. Further, the expansion process BC does not become an ideal isentropic change due to the influence of leakage, friction, and fluid resistance. Therefore, in practice, the relationship between the volume and pressure of the working fluid in the expansion process is preferably expressed using experimental data or an approximate expression obtained from the experimental data. Obtaining the target volume Vbo ′ obtains higher operating efficiency than when obtaining the ideal volume.
The above-described working fluid state holding unit 61 holds data and approximate expressions representing the relationship between the volume and pressure of the above-described working fluid and the relationship between the saturation pressure and temperature of the above-described working fluid. In other words, the working fluid state holding unit 61 that holds the relationship between the volume and pressure of the working fluid when expanding in the expansion chamber is provided, and the target volume Vbo ′ (that is, the target amount that maximizes the refrigeration cycle efficiency) is provided using this relationship. ), It is possible to obtain higher driving efficiency in practice.

As described above, in this embodiment, the electromagnetic valve 40 is installed between the expansion chamber 25 and the suction hole 27 of the expander unit, and the low-pressure pressure Pl of the refrigeration cycle is detected. The electromagnetic valve control unit 60 controls the opening time (Tcl-Top) of the electromagnetic valve 40 so that the high pressure Ph becomes the optimum pressure Popt that maximizes the refrigeration cycle efficiency, and the working fluid entering the working chamber 25 is controlled. Since the flow rate is adjusted, in other words, the volume of the expansion chamber in which the working fluid can be sucked by varying the opening / closing timing of the suction valve is set to an ideal volume, so that the rotor 23 of the expander is driven by the compressor. Even when directly connected to the shaft, an operating condition (constraint) of “density ratio = constant” can be eliminated, and an expander-integrated compressor that always recovers power from a high-pressure working fluid to the maximum can be provided.
In addition, by using the compressor of the present embodiment for a heat pump device, controlling the opening / closing timing of the suction valve of the compressor, the amount of working fluid led to the expansion chamber is set to a target amount that maximizes the refrigeration cycle efficiency. The operating efficiency of the heat pump device can always be made high.

  The compressor according to the present invention and the heat pump device using the compressor open and close the suction valve installed in the suction hole of the expander, and control the expansion chamber volume of the expander into which the working fluid enters to maximize the pressure from the high-pressure working fluid. Since power recovery is performed to the limit, high operating efficiency can be obtained at all times, and the compressor is applied to an expander-integrated compressor, a heat pump device using the compressor, an air conditioner, and the like.

The longitudinal cross-sectional view of the compressor of the Example by this invention Cross-sectional view of the expander section in the compressor of the present embodiment PV diagram of working chamber when solenoid valve is normally open in this embodiment The figure which showed the relationship between the opening / closing timing of the solenoid valve in this embodiment, and the flow rate of the working fluid entering the working chamber System configuration diagram of conventional air conditioner Mollier diagram when the working fluid is carbon dioxide in a conventional air conditioner System configuration diagram of another conventional air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Airtight container 12 Compressor part 13 Compression chamber 14 Drive shaft 15, 23 Rotor 16 Electric motor part 17 Stator 18 Rotor 20 Expander part 21 Cylinder 22 Small clearance 23 Rotor 24 Vane 25 Actuation chamber 26 Power recovery shaft 27 Suction hole 28 Discharge hole 31 Cover 32 Suction path 33 Discharge chamber 34 Discharge path 35 Suction pipe 36 Discharge pipe 40 Solenoid valve 48 Discharge pressure sensor 50 Suction temperature sensor 51 Discharge temperature sensor 60 Solenoid valve control section 61 Working fluid state holding section

Claims (9)

A compressor section having a compression chamber and a drive shaft, and compressing the working fluid sucked into the compression chamber by rotating the drive shaft;
An expansion chamber, a suction hole for guiding the working fluid to the expansion chamber with an expander suction pressure, a discharge hole for discharging the working fluid from the expansion chamber, and a power recovery shaft connected to the drive shaft, An expander unit that obtains rotational power of the power recovery shaft by expanding the working fluid sucked into the expansion chamber,
A pressure detection means for detecting an expander discharge pressure of the working fluid discharged from the discharge hole, and a suction valve in the suction hole;
A target obtained from the expander discharge pressure obtained by the pressure detection means and the expander suction pressure as a target for maximizing the refrigeration cycle efficiency, with respect to the amount of working fluid guided from the suction hole to the expansion chamber A compressor characterized in that the opening / closing timing of the intake valve is variable so as to be a quantity. A suction temperature sensor for measuring a suction temperature of the working fluid sucked into the suction hole, and a discharge temperature sensor for measuring a discharge temperature of the working fluid discharged from the discharge hole;
The compressor according to claim 1, wherein the compressor is configured to calculate a target expander suction pressure from the suction temperature and the discharge temperature.   The compressor according to claim 2, wherein the pressure detection means is configured to obtain the expander discharge pressure by converting the discharge temperature measured by the discharge temperature sensor.   The compressor according to any one of claims 1 to 3, wherein the suction valve is an electromagnetic valve.   The opening timing at which the suction valve is opened from the closed time is defined as the suction start time at which the volume of the expansion chamber is minimized, and the closing timing at which the suction valve is opened from the closed time is defined as the volume of the expansion chamber from the suction start time. The compressor according to any one of claims 1 to 4, wherein the compressor has a control function of setting a time until the value reaches a maximum.   Provided is a working fluid state holding unit that holds the relationship between the volume and pressure of the working fluid when expanding in the expansion chamber, and uses the relationship between the volume and pressure of the working fluid held by the working fluid state holding unit. The compressor according to any one of claims 1 to 5, wherein a target amount is obtained.   The compressor according to any one of claims 1 to 6, wherein the compressor is operated using a working fluid that expands from a supercritical phase to a liquid phase or a gas-liquid two phase.   The compressor according to any one of claims 1 to 7, wherein the compressor is operated using a working fluid containing carbon dioxide as a main component. The compression according to any one of claims 1 to 8, wherein an amount of the working fluid guided to the expansion chamber by controlling the opening / closing timing of the suction valve can be set to the target amount that maximizes the refrigeration cycle efficiency. A heat pump device using a machine.

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