JP2007298207A - Refrigerating cycle device and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle device applying an expander of high efficiency and high reliability. <P>SOLUTION: This refrigerating cycle device comprises a compressor 1, a radiator 2, the expander 3, an evaporator 4, a suction volume control means 8 disposed at a suction side of the expander 3 for changing suction volume of a refrigerant flowing into the expander, and a control valve 8 connected with the expander 3 in series to expand the refrigerant, and by properly controlling them, electric power can be collected by the expander 3 in maximum in over load and transient time, and a degree of superheat can be surely controlled by the control valve 8. Further a stable state can be controlled more quickly with high response in comparison with a case when only the suction volume control means 9 is used, and the refrigerating cycle device of high efficiency and high reliability can be provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power recovery apparatus that uses an expander that uses an expansion force such as a refrigerant, and more particularly to a refrigeration cycle apparatus that uses an expander to improve the efficiency of a vapor compression refrigeration apparatus that uses carbon dioxide as a refrigerant.

  2. Description of the Related Art As a power recovery type refrigeration cycle that recovers expansion energy of a refrigerant with an expander and uses it as part of work for compressing the refrigerant with a compressor, one using an expander-integrated compressor is known. (For example, see Patent Document 1).

  A refrigeration cycle using a conventional expander-integrated compressor will be described. FIG. 18 shows a refrigeration cycle using an expander-integrated compressor having the same configuration as that of Patent Document 1. This refrigeration cycle includes a compressor 1, a gas cooler 2, an expander 3, an evaporator 4, an electric motor 5, a shaft 6 directly connecting the compressor 1, the expander 3, and the electric motor 5, and an expander suction rod 11. Has been. The refrigerant is compressed from room temperature low pressure to high temperature high pressure in the compressor 1 and then cooled to room temperature high pressure in the gas cooler 2. And after expanding to low temperature and low pressure in the expander 3, it is heated by the evaporator 4 to normal temperature.

  In such a refrigeration cycle system, the expander 3 recovers the expansion energy of the refrigerant, converts it into rotational energy of the shaft 6, and uses part of the work for driving the compressor 1 as an electric motor 5. The power of the engine was reduced and high-efficiency operation of the cycle was realized.

  FIG. 19 shows a Mollier diagram using carbon dioxide, which is a high-pressure refrigerant, as an example of the operation of such a refrigeration cycle apparatus. In this cycle, a gas cooler is connected from the compressor outlet (point D). The refrigerant (point A) cooled by 2 flows into the expander 3 and is expanded by isentropic expansion in the expander 3. In this case, only the enthalpy amount “ha” between the evaporator inlet “point B” and the evaporator inlet “point E” in the case where the expansion valve is isoenthalpy-expanded from “point A” by an expansion valve as in the prior art, Collected on the system side. As a result, only the value “hb-ha” obtained by subtracting the recovered power “ha” from the necessary input “hb” needs to be actually input to the compressor. Efficient operation is achieved.

  A positive displacement expander such as a rotary expander is known as the expander that generates power by expanding a high-pressure fluid (for example, Patent Document 2). The expander includes a cylinder and a piston that revolves along the inner peripheral surface of the cylinder, and a working chamber formed between the cylinder and the piston is partitioned into a suction / expansion side and a discharge side. . As the piston revolves, the working chamber is switched from the suction / expansion side to the discharge side and from the discharge side to the suction / expansion side. The discharging action is performed simultaneously in parallel.

  In the expander, the angle range of the suction process in which high-pressure fluid is supplied into the cylinder during one rotation of the piston and the range of the expansion process in which the fluid is expanded are determined in advance. That is, in this type of expander, the expansion ratio (density ratio between the intake refrigerant and the exhaust refrigerant) is generally constant. The high pressure fluid is introduced into the cylinder in the angular range of the suction process, while the fluid is expanded at a predetermined expansion ratio in the remaining angular range of the expansion process, and the rotational power is recovered.

Furthermore, in the expander described in Patent Document 3, the actual expansion ratio of the refrigeration cycle varies depending on the design expansion ratio of the cycle or the uniqueness of the expander due to fluctuations in operating conditions such as switching between cooling operation and heating operation and a change in outside air temperature. Even when the expansion ratio deviates, two of the plurality of rotary mechanism portions of the expander that are connected to each other communicate the low pressure chamber of the front rotary mechanism portion with the high pressure chamber of the rear rotary mechanism portion. The refrigeration cycle is designed for expansion of the expander by an injection passage for guiding a part of the high-pressure fluid to the working chamber in the expansion process and a flow control mechanism provided in the injection passage. Even in a condition where the ratio is smaller than the ratio, the expansion chamber does not enter an overexpanded state in which the internal pressure of the expansion chamber is lower than the low pressure of the refrigeration cycle.
JP 2000-329416 A JP-A-8-338356 JP 2005-256667 A

  Such an expander is configured so that the maximum power recovery efficiency can be obtained when the operation is performed at the designed expansion ratio. The ratio between the high pressure and the low pressure of the refrigeration cycle (pressure ratio) ) Is reduced, the amount of suction is increased by flowing a high-pressure fluid by the injection so that the pressure ratio of the expander is reduced, and the pressure ratio is controlled to be equal to the pressure ratio of the refrigeration cycle. However, during transient conditions such as start-up and overload in winter, the refrigerant flow rate is further reduced even if the intake volume by injection is set to zero and operation is performed at the minimum intake volume that is the original designed intake volume of the expander. Therefore, the degree of superheat at the outlet of the evaporator or the inlet of the compressor cannot be controlled to a predetermined value, and the compressor may be damaged by liquid compression. In addition, even when the degree of superheat can be ensured, the refrigerant flow rate cannot be controlled to be smaller than when operating with the minimum suction volume, so there is a problem that the response time for the degree of superheat to become a predetermined value becomes longer. .

  Accordingly, the present invention solves the above-described problem. An expander having a suction volume control means capable of varying the suction volume sucked into the expander and a control valve are arranged in series, and the minimum suction is achieved by the suction volume control means. By setting the volume and using a control valve in addition to that, the flow rate can be controlled to be even smaller, so that the degree of superheat can be ensured accurately in a transient state such as start-up or an overload in winter. In addition, the refrigeration cycle that can speed up the response for setting the degree of superheat to a predetermined value, has the reliability and quick response of the compressor, and can maximize the power recovered by the expander An object is to provide an apparatus.

The refrigeration cycle apparatus using the expander according to the present invention is
A positive displacement compressor that compresses the working fluid;
A radiator for cooling the refrigerant compressed by the compressor;
A positive displacement expander for expanding the working fluid;
An evaporator for evaporating the refrigerant expanded by the expander;
An electric motor that connects the compressor and the expander uniaxially in a sealed container;
A refrigerant pipe that is connected in the order of the compressor, the radiator, the expander, and the evaporator and circulates a refrigerant;
A suction volume control means capable of changing the suction volume of the refrigerant flowing into the expander on the suction side of the expander;
A control valve for expanding the refrigerant connected in series with the expander is provided.
Thus, by providing the control valve in series with the expander, the superheat degree of the refrigerant sucked by the compressor is maintained at a predetermined value, so that the liquid phase refrigerant is prevented from being sucked into the compressor, and the compressor Therefore, the reliability of the components can be improved. In addition, the control valve may be disposed upstream of the expander having the suction volume control means.

  Thereby, the recovery power of the expander can be increased more than when the control valve is disposed on the downstream side.

Furthermore, a first temperature detecting means attached to either the outlet side of the expander or in the evaporator, and detecting the temperature of the refrigerant;
A second temperature detecting means attached between the outlet of the evaporator and the inlet of the compressor and detecting the temperature of the refrigerant;
A control unit that controls using signals from the first temperature detection unit and the second temperature detection unit;
The suction volume control means and the control valve may be controlled by a signal from the control unit to change the refrigerant supply amount so that the degree of superheat at the evaporator outlet or the compressor inlet becomes a predetermined value. .

  Further, the first temperature detecting means for detecting the temperature of the refrigerant is a pressure detecting means for detecting the pressure of the refrigerant, and the pressure detecting means is attached between the outlet side of the expander and the inlet side of the compressor. May be.

  This makes it possible to reliably calculate the degree of superheat, thereby increasing the reliability for ensuring the degree of superheat.

  The suction volume of the refrigerant flowing into the expander by the suction volume control means may be greater than or equal to the original designed suction volume of the expander.

  When the degree of heating is smaller than a predetermined value, the first or second control unit sets the superheat degree when the suction volume control means minimizes the suction volume of the refrigerant flowing into the expander by the suction volume control means. The control valve may be controlled to control to a predetermined value.

  The first or second control unit is a minimum suction volume that minimizes the suction volume of the refrigerant flowing into the expander by the suction volume control means. When the opening degree of the control valve is not the maximum, the degree of superheat is set. The control valve may be controlled to control to a predetermined value.

  Thus, even when the minimum suction volume is set by the suction volume control means, the mass flow rate can be changed by using the control valve, and the degree of superheat can be reliably ensured to a predetermined value. The reliability of the compressor can be ensured.

  At the start of the refrigeration cycle, the electric motor is driven, and the suction volume control means is controlled by the controller to set the minimum suction volume.

  At the start of the refrigeration cycle, the electric motor is driven, the control unit is controlled by the control unit, and the pressure of the high-pressure side refrigerant is controlled to a predetermined pressure.

  As a result, at the time of start-up, it is possible to ensure the degree of superheat and at the same time realize the pressure of the high-pressure side refrigerant to a predetermined pressure with quick response.

  The suction volume control means may be a volume variable means capable of changing the refrigerant suction volume of the expander.

Thus, the suction volume can be changed by changing the suction volume sucked into the expander.

  According to the refrigeration cycle apparatus of the present invention, in an expander having suction volume control means that can change the suction volume flowing into the expander, by providing a control valve in series, at the time of overload or start-up in heating Therefore, it is possible to reliably ensure the degree of superheat and to realize a highly reliable system without destroying other components. In addition, by utilizing the characteristics with a wider control range than the suction volume control mechanism, it is possible to ensure the degree of superheat reliably and responsively even in a transient state, and furthermore, the power is recovered by the expander, so it is highly efficient It becomes possible to drive to.

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

(First embodiment)
In FIG. 1, the refrigerant circuit figure of the refrigerating-cycle apparatus in this embodiment is shown. Further, members having the same functions as those shown in the explanatory diagrams of the conventional example are denoted by the same reference numerals, and description thereof is omitted.

The refrigeration cycle apparatus of this embodiment includes a refrigerant circuit 10 in which a compressor 1, a gas cooler 2, an expander 3, and an evaporator 4 are connected in order by a refrigerant pipe 7, and the compressor 1 and the expander 3 are connected to each other. The electric motor 5 is uniaxially connected, and the arrow indicates the direction in which the refrigerant flows. A control valve 8 is provided between the gas cooler 2 and the expander 3. The expander 3 includes suction volume control means 9 that can change the suction volume. The refrigerant circuit 10 is filled with a refrigerant that becomes a supercritical state in a high-pressure portion (portion from the compressor 1 through the gas cooler 2 to the expander 3). In the present embodiment, carbon dioxide (CO ₂ ) is filled as such a refrigerant. However, the type of the refrigerant is not particularly limited, and the refrigerant in the refrigerant circuit 10 may be a refrigerant that does not enter a supercritical state during operation.

  Further, in the refrigeration cycle apparatus of the present embodiment, the control unit 23 uses the first temperature sensor 21 in the evaporator 4 and the outlet side of the evaporator as inputs for controlling the control valve 8 and the suction volume control means 9. The second temperature sensor 22 is provided.

  Next, an operation in which the volume ratio (discharge volume / suction volume) is changed by the suction volume control means 9 in the present embodiment will be described.

  FIG. 2 shows the relationship between the suction volume controlled by the suction volume control means 9 and the volume ratio. When the suction volume is controlled by the suction volume control means 9 to the minimum suction volume Vmin, the volume ratio becomes maximum γmax. Generally, the minimum suction volume Vmin is designed so as to be the minimum suction volume Vmin during normal operation such as in winter. Further, as the suction volume is increased, the volume ratio decreases because the discharge volume is constant.

  The operation of the refrigeration cycle of the refrigeration cycle apparatus will be described.

  In FIG. 1, the compressor 1 is driven by an electric motor 5 controlled by an inverter (not shown), and the refrigerant is compressed by the compressor 1. The compressed refrigerant is cooled by the radiator 2 and then passes through the control valve 8 and the expander 3. At this time, the refrigerant expands by passing through the control valve 8 and the expander 3, absorbs heat from the outside in the evaporator 4 and vaporizes, and then returns to the compressor 1 again.

Next, the control method and effects of the control valve 8 and the suction volume control means 9 shown in FIG. 1 will be described. FIG. 3 shows data on the efficiency of the refrigeration cycle with respect to the radiator outlet pressure and radiator outlet temperature. In normal operation, the suction volume control means 9 is controlled so that the radiator outlet is on the optimum efficiency pressure line shown in FIG. FIG. 4 shows a ph diagram of the vapor compression refrigeration apparatus. As shown in cycle S1 of FIG. 4, the degree of superheat is ensured during normal operation, and the high pressure is also appropriately controlled by the suction volume control means 9 on the optimum efficiency pressure line shown in FIG. That is, during such normal operation, the control valve 8 is controlled to be fully opened, and the suction volume control means 9 changes the suction volume to control the high pressure side of the radiator. Further, the minimum suction volume Vmin of the expander is designed to satisfy this condition. However, since the outlet temperature of the evaporator 4 decreases and the cycle changes during an overload such as in winter, the cycle becomes S2 shown in FIG. 4 and the degree of superheat cannot be secured at the set value. In this cycle apparatus, the following control is performed to ensure the degree of superheat in such a state. FIG. 5 shows a flowchart of the control method. First, signals from the first temperature sensor 21 and the second temperature sensor 22 are taken into the control unit 23 (s101). From these signals, the degree of superheat TSH on the right side is calculated based on point E where the point C in the cycle S2 shown in FIG. 4 intersects the refrigerant saturation curve (s102), and it is determined whether the degree of superheat is greater or smaller than the set value. (S103). Inside the controller 23, the degree of superheat is obtained from the difference (T 2 −T 1) between the temperature T 1 from the first temperature sensor 21 and the temperature T 2 from the second temperature sensor 22. The predetermined superheat degree according to the present embodiment is set to 5 [° C.], and if the control unit 23 is smaller than this set value, it is determined whether the suction volume control means 9 is the minimum suction volume Vmin (s104). In the case of the minimum suction volume Vmin, since the suction volume of the expander cannot be reduced any more, the opening degree of the control valve 8 is set small (S105). If it is not the minimum suction volume, the flow rate can be reduced by the suction volume control means 9, and therefore the expander suction volume is reduced by the suction volume control means 9 (s106). FIG. 6 is a diagram showing the suction volume V controlled by the suction volume control means 9 and the control timing of the control valve 8 in this case. First, when the degree of superheat falls below the set value of 5 [° C.], the suction volume control means 9 sets the suction volume to be small at the next control timing. This operation is repeated to control the suction volume to the minimum suction volume. Even in this case, when the degree of superheat is 5 [° C.] or less, the opening degree of the control valve 8 is set small here. Similarly, by repeating these operations, the superheat degree can be secured even when the superheat degree becomes smaller than the set value, and a Mollier diagram as shown in cycle S3 of FIG. 4 is obtained. Next, when the degree of superheat is larger than the set value in s103, it is determined whether the opening degree of the control valve is maximum (s107), and when it is maximum, the suction volume is increased by the suction volume control means 9 (s108). ). If the control valve opening is not the maximum, the opening of the control valve 8 is increased (s109). By repeating these operations, even when the superheat degree is larger than the set value, the set superheat degree can be controlled. When the degree of superheat settles to the set value by these controls, the suction volume control means 9 is controlled so as to be in the normal operation state and the optimum efficiency pressure line.

  Next, the expander-integrated compressor and volume control means 9 used in this embodiment will be described.

  FIG. 7 shows a longitudinal sectional view of the expander-integrated compressor. A scroll compressor 1 is disposed on the upper side of the inside of the sealed container 41, a two-stage rotary expander 3 is disposed on the lower side, and an electric motor 5 including a rotor 21 and a stator 22 is disposed therebetween. These are connected by a shaft coupling portion 32.

  However, the types of the compressor 1 and the expander 3 may be other rotary compressors. For example, a rotary type, a scroll type, and a multi-vane type can be suitably used. Furthermore, the arrangement relationship of the compressor 1, the expander 3, and the electric motor 5 is not limited at all.

As shown in FIG. 7, the scroll compressor 1 includes a fixed scroll 74, an orbiting scroll 73, an Oldham ring 75, a bearing member 77, a muffler 79, a suction pipe 71, and a discharge pipe 72. Has been. The orbiting scroll 73 is fitted to the eccentric shaft of the compressor shaft 76 and is restrained from rotating by the Oldham ring 75. The orbiting scroll 73 has a spiral wrap 73a, the fixed scroll 74 has a wrap 74a, and the wrap 73a and the wrap 74a mesh with each other. The orbiting scroll 73 performs an orbiting motion as the shaft 76 rotates, and the volume of the orbiting scroll 71 is reduced while the crescent-shaped working chamber 80 formed between the wraps 73a and 74a moves from the outside to the inside. The working fluid sucked from the air is compressed, and the sealed container is discharged from the discharge hole 72a provided at the center of the fixed scroll 74 and the flow path 72b provided in the fixed scroll 74 and the bearing member 77 via the inner space 79a of the muffler 79. 41 is discharged into the internal space 41a. While the working fluid stays in the internal space 41a, the mixed lubricating oil is separated by gravity, centrifugal force, or the like, and then discharged from the discharge pipe 72 to the refrigeration cycle.

  In FIG. 7, the two-stage rotary expander 3 includes a first cylinder 42, a second cylinder 43 that is thicker than the first cylinder 42, and an intermediate plate 57 that partitions them. The first piston 45 fitted to the eccentric portion 44a of the shaft 44 rotates eccentrically in the first cylinder 42, and the second piston 46 fitted to the eccentric portion 44b of the shaft 44 is In the second cylinder 43, an eccentric rotational movement is performed. The first vane 47 (shown in FIG. 9) is reciprocally held in the vane groove 42a (shown in FIG. 9) of the first cylinder 42, the tip is in contact with the first piston 45, and the second vane (Not shown) is reciprocally held in a second vane groove (not shown) of the second cylinder 43, and the tip contacts the second piston 46. A first spring 49 (shown in FIG. 9) that pushes the first vane 47 is in the first vane groove 42a, and a second spring (not shown) that pushes the second vane (not shown) is the second. Stored in a vane groove (not shown). The upper end plate fixing portion 61 is provided with a suction pipe 53 and a discharge pipe 54. An upper end plate movable portion 62 that rotates so as to contact the upper end plate fixing portion 61 and a lower end plate 52 that contacts the muffler 58 are provided. The bearing for supporting the shaft 44 is provided. The discharge side of the first cylinder 42 and the suction side of the second cylinder 43 communicate with each other through a communication hole 57a provided in the intermediate plate 57, and function as one working chamber. After the high-pressure working fluid flows into the working chamber of the first cylinder 42 from the suction pipe 53 through the first cylinder suction path 42c (described in FIG. 9) and the second suction hole 62f provided in the upper end plate movable portion 62. Then, after expanding in the working chamber formed from the working chamber of the second cylinder 43 and rotating the shaft 44 to become a low pressure, it is once discharged into the inner space 52c of the muffler 58 through the lower end plate 52. Then, it is discharged from the discharge pipe 54 to the refrigeration cycle via the discharge flow path 52b. Here, a discharge valve 59 is provided in the discharge hole 52 a of the lower end plate 52. The discharge valve 59 is a thin metal plate, is installed so as to close the discharge hole 52a from the inner space 52c side of the muffler 58, and is a differential pressure valve that opens when the pressure on the upstream side of the discharge valve 59 becomes higher than the pressure on the downstream side. It has become.

  8A is a perspective view of the upper end plate fixing portion 61 of the expander 3 in the expander-integrated compressor of FIG. 7, and FIG. 8B is an expander in the expander-integrated compressor of FIG. FIG. 8C is a perspective view of the expander-integrated compressor of FIG. 7 in which the upper end plate fixing portion 61 and the movable portion 62 of the expander 3 are assembled. is there.

  As shown in FIG. 8A, the fixed portion 61 has a cylindrical surface 61a having the same central axis as the shaft 44, a cylindrical surface 61b having an inner diameter smaller than the cylindrical surface 61a, and a stepped portion 61c therebetween. . In addition, an inflow path 61d through which the working fluid from the suction pipe 53 is guided, an inflow path 61e branched in the vertical direction therefrom, and a discharge flow path 61g are provided. Further, as shown in FIG. 9, the first cylinder 42 is provided with an inflow path 42c and a first suction hole 42d in communication with the inflow path 42c as a flow path communicating with the inflow path 61e.

As shown in FIG. 8B, the movable portion 62 has a shaft hole 62e into which the shaft 44 is fitted on the inner side, and on the outer side, a cylindrical surface 62b to be fitted to the cylindrical surface 61a of the fixed portion 61, and The cylindrical surface 62c is fitted to the cylindrical surface 61b of the fixed portion 61, and a circumferential channel groove 62d is provided 180 degrees in the rotational direction of the shaft 44 on the cylindrical surface 62b. The cylindrical surface 62c is provided with a gear 62a in the circumferential direction, and has a second suction hole 62f from the flow path groove 62d toward the lower side.

  As shown in FIG. 8C, the fixed portion 61 and the movable portion 62 are fitted, and the movable portion 62 is rotatably supported inside the fixed portion 61. Then, by rotating the movable portion 62, the second suction hole 62f can be rotated around the shaft 44. At this time, the step (not shown) between the step 61c of the fixed portion 61 and the cylindrical portions 62b and 62c of the movable portion 62 comes into contact with each other, thereby preventing the movable portion 62 from coming out of the fixed portion 61 upward. Yes. The lower end surface of the fixed portion 61 and the lower end surface of the movable portion 62 constitute the same plane. The upper end plate fixing portion 61 includes a gear 65 (shown in FIG. 7) that meshes with a gear 62a provided on the movable portion 62, and a rotary electric motor 63 (shown in FIG. 7) that drives the gear 65. The upper end plate movable portion 62 can be rotated around the axis of the shaft 44 by the rotary electric motor 63.

  The upper end plate movable portion 61 and the fixed portion 62 in the present embodiment have the following functions. This is a suction volume control mechanism in which the working fluid that has flowed into the two-stage rotary expander 3 from the suction pipe 53 is divided into two paths from the inflow path 61 d of the upper end plate fixing portion 61 and flows into the upper working chamber 55. The first path is a path that passes from the inflow path 61d to the inflow path 61e, the inflow path 42c of the first cylinder 42, and the first suction hole 42d, and the second path is a flow of the movable part 62 from the inflow path 61d. This is a path through the path groove 62d and the second suction hole 62f. That is, the suction volume of the working fluid flowing into the upper working chamber 55 can be changed by controlling and changing the position of the second suction hole. Hereinafter, the position and function of the movable portion 62 will be described.

  9A and 9B are cross-sectional views taken along D1-D1 of the expander of the expander-integrated compressor of FIG. Here, the relationship between the position and function of the first suction hole 42d and the second suction hole 62f will be described.

  In the present embodiment, the position of the first suction hole 42d is fixed to 20 deg around the shaft 44 with respect to the position of the vane 47, whereas the position of the second suction hole 62f can be changed from the outside. Is possible. FIG. 4A shows a case where the rotation angle φ of the second suction hole 62f is 20 deg with respect to the position of the vane 47 around the shaft 44, and FIG. 4B shows a case where it is 90 deg. Needless to say, the rotation angle φ of the second suction hole 62f can be freely changed from 0 deg to 360 deg. Next, functions will be described. When the position of the upper end plate movable portion 62 is controlled and the position φ of the second suction hole 62f is set to 20 deg, FIG. 9A is obtained. Since the second suction hole 62f is at the same position as the first suction hole 42d, the suction volume is the same as when only the first suction hole 42d is provided. When the position φ of the second suction hole 62f is 90 deg, FIG. 9B is obtained. Since the position φ of the second suction hole 62f is larger than the angle of the first suction hole 42d, the suction time becomes longer and the suction volume becomes larger than that in FIG. FIG. 10 shows a graph of suction volume, discharge volume, and volume ratio (discharge volume / suction volume) when the angle of the upper end plate movable portion 62 is changed. When the rotation angle of the upper end plate movable portion 62 is increased, the suction time is increased, thereby increasing the suction volume. Further, the discharge volume is constant because it does not depend on the position of the upper end plate movable portion 62. That is, the volume ratio is maximized when the angle of the upper end plate movable portion 62 is minimized.

As described above, according to the present embodiment, the rotational position of the upper end plate movable portion 62 that is the suction volume control means 9 provided in the expander 3 and the control valve 8 connected in series with the expander are controlled. Thus, the degree of superheat can be ensured with certainty. Further, since the liquid-phase refrigerant is prevented from being sucked into the compressor 1, the liquid-phase refrigerant and the gas-phase refrigerant are separated on the outlet side of the evaporator 4 and only the gas-phase refrigerant is directed to the compressed air 1. Therefore, it is possible to provide a highly reliable refrigeration cycle apparatus without disposing an accumulator that flows out. Further, in normal operation, control is performed by the suction volume control means 9 without using the control valve 8, so that power can be recovered by the expander 3, so that highly efficient operation is possible. . Further, by controlling the suction volume control means 9 and the control valve 8 at the time of activation, the high-pressure side refrigerant can be controlled to a predetermined pressure earlier than the refrigeration cycle apparatus in which the control valve 8 is not installed.

  Furthermore, the refrigerant circuit 10 shown in FIG. 1 is not limited to the refrigerant circuit 10 that distributes the refrigerant in only one direction. The expander-integrated compressor may be provided in a refrigerant circuit capable of changing the refrigerant flow direction. For example, as shown in FIG. 11, it is also possible to provide an expander-integrated compressor in a refrigerant circuit capable of heating operation and cooling operation by having a four-way valve 13 or the like.

Further, in the present embodiment, the volume variable means that can variably control the suction volume according to the rotation angle of the upper end plate movable portion 62 as the suction volume control means 9 has been described. However, the high-pressure fluid on the expander suction side is expanded by the expansion of the expander 3. The structure may be such that the suction volume to the expander 3 is changed by an injection passage for guiding to the working chamber of the process and a flow control mechanism provided in the injection passage. In this case, the same applies to the time for suctioning the position of the upper end plate movable portion 62, which is the horizontal axis shown in FIG.
(Second Embodiment)
Although the first temperature detecting means is used for the control unit for controlling the degree of superheat according to the first embodiment, the pressure detecting means 25 is connected to the outlet of the expander 3 and the inlet of the compressor 1 as shown in FIG. The suction volume control means 9 and the control valve 8 may be controlled by calculating the degree of superheat by the control unit 24 using these signals. Since the refrigeration cycle apparatus and the control method are the same as those in the first embodiment, a description thereof will be omitted.

  As a method of calculating the degree of superheat, first, the pressure detection means 25 detects the pressure on the low pressure side, and obtains the evaporation temperature using a table prepared in advance. Further, the degree of superheat can be obtained by taking the difference from the compressor intake temperature obtained by the first temperature detecting means.

  As described above, according to the present embodiment, by using the pressure detection means 25 instead of the first temperature detection means, the compressor can be protected by liquid phase compression, and a highly reliable refrigeration cycle apparatus is obtained. .

  As described above, in the first and second embodiments, the case where the superheat degree control is performed according to the present invention has been described. In addition, the present invention can also be applied to the case of performing control of another control target. That is, in the refrigeration cycle apparatus having the configuration shown in FIG. 1, the control valve 8 is controlled to be fully opened during normal operation, and the suction volume is changed by the suction volume control means 9 to control the high pressure side of the radiator. At the time of overload such as in winter, or when it is unsteady such as when the load fluctuates, that is, the control of the controlled object within the target control range becomes impossible or difficult only by the control of the suction volume control means 9, or depending on the target control range When it is desired to converge quickly, the control target is controlled to the target control range by making the opening degree of the control valve 8 smaller than the fully open position. As a specific control method, the measurement value in step S101 and the control target in step S102 may be selected according to the target control target in the flowchart of FIG.

A typical control object other than the degree of superheat is COP. More specifically, the pressure on the high pressure side of the refrigeration cycle is controlled so that the COP in the refrigeration cycle is maximized. As measured values in this case, the temperature and pressure of the refrigerant at the outlet of the radiator 2 in FIG. 1 are measured. As an alternative, the discharge pressure of the compressor 1 can also be used.
(Third embodiment)
Further, when the refrigeration cycle is started, the electric motor 5 may be driven, and the suction volume control means 9 may be controlled by the control unit 23 to minimize the expander suction amount that is the minimum suction volume. By doing so, the amount of refrigerant flowing through the expander can be made smaller than the amount of suction that can be controlled by the suction volume means 9, so that the control range of the amount of refrigerant can be increased. Since the refrigeration cycle apparatus and the control method are the same as those in the first embodiment, a description thereof will be omitted.

As described above, according to this embodiment, it is possible to control the radiator outlet so as to be on the optimum efficiency pressure line shown in FIG. 3 in a shorter time.
(Fourth embodiment)
Further, the control valve 8 may be controlled so that the pressure of the refrigerant on the high pressure side becomes a predetermined pressure when the refrigeration cycle is activated or for a certain period after the activation. By doing so, the amount of refrigerant flowing through the expander can be made smaller than the amount of suction that can be controlled by the suction volume means 9, so that the control range of the amount of refrigerant can be increased. Since the refrigeration cycle apparatus and the control method are the same as those in the first embodiment, a description thereof will be omitted.

As described above, according to the present embodiment, it is possible to control the outlet pressure of the radiator 2 to be on the optimum efficiency pressure line shown in FIG. 3 in a shorter time.
(Fifth embodiment)
The control valve 8 according to the first embodiment is installed between the radiator 2 and the expander 3. However, the control valve 8 according to the present invention may be installed between the expander 3 and the evaporator 4. This will be described in detail below with reference to the drawings. In addition, members having the same functions as those shown in the explanatory diagrams of Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 13, the refrigerant circuit figure of the refrigerating-cycle apparatus in this embodiment is shown. The refrigeration cycle apparatus of the present embodiment includes a refrigerant circuit 10 in which a compressor 1, a gas cooler 2, an expander 3, and an evaporator 4 are connected in order, and the compressor 1 and the expander 3 are connected to the electric motor 5. The arrows indicate the direction in which the refrigerant flows. A control valve 8 is provided between the expander 3 and the radiator 4. In FIG. 13, the same components as those in FIG.

  The operation of the refrigeration cycle of the refrigeration cycle apparatus will be described.

  In FIG. 13, the compressor 1 is driven by the electric motor 5 controlled by an inverter (not shown), and the refrigerant is compressed by the compressor 1. The compressed refrigerant is cooled by the radiator 2 and then passes through the control valve 8 and the expander 3. At this time, the refrigerant expands by passing through the expander 3 and the control valve 8 in this order, absorbs heat from the outside in the evaporator 4 and vaporizes, and then returns to the compressor 1 again.

  The expander-integrated compressor in the present embodiment has the same configuration as the expander-integrated compressor shown in FIG.

  Further, the control method and effects of the control valve 8 and the suction volume control means 9 shown in FIG. 13 are the same as the contents shown in the first embodiment.

As described above, according to the present embodiment, by controlling the rotational position of the upper end plate movable portion 62 in the expander 3 provided with the suction volume control means 9 and the control valve 8 connected in series downstream thereof, The degree of superheat can be ensured reliably. Further, since the liquid-phase refrigerant is prevented from being sucked into the compressor 1, the liquid-phase refrigerant and the gas-phase refrigerant are separated on the outlet side of the evaporator 4 and only the gas-phase refrigerant is directed to the compressed air 1. Therefore, it is possible to provide a highly reliable refrigeration cycle apparatus without disposing an accumulator that flows out. Further, in normal operation, control is performed by the suction volume control means 9 without using the control valve 8, so that power can be recovered by the expander 3, so that highly efficient operation is possible. .
(Sixth embodiment)
The control valve 8 and the expander 3 according to the first embodiment are sequentially installed in series. Furthermore, a bypass line 15 and a bypass valve 16 are provided as a configuration according to the present invention. This will be described in detail below with reference to the drawings.

  In FIG. 14, the refrigerant circuit figure of the refrigerating-cycle apparatus in this embodiment is shown. The refrigeration cycle apparatus of the present embodiment includes a refrigerant circuit 10 in which a compressor 1, a gas cooler 2, an expander 3, and an evaporator 4 are connected in order, and the compressor 1 and the expander 3 are connected to the electric motor 5. The arrows indicate the direction in which the refrigerant flows. A control valve 8 is provided between the gas cooler 2 and the expander 3. In FIG. 14, the same components as those in FIG. One end of the bypass pipe 15 in which the bypass valve 16 is installed is connected between the radiator 2 and the control valve 8, and the other end is connected between the expander 3 and the evaporator 4.

  The operation of the refrigeration cycle of the refrigeration cycle apparatus will be described. In FIG. 14, the compressor 1 is driven by an electric motor 5 controlled by an inverter (not shown), and the refrigerant is compressed by the compressor 1. The compressed refrigerant is cooled by the radiator 2, and then is branched and expanded into a circuit that passes through the control valve 8 and the expander 3 and a pipeline that passes through the bypass valve 16. The expanded refrigerant absorbs heat from the outside in the evaporator 4 and vaporizes, and then returns to the compressor 1 again.

  The expander-integrated compressor in the present embodiment has the same configuration as the expander-integrated compressor shown in FIG.

  The control method and effects of the control valve 8 and the suction volume control means 9 shown in FIG. 14 will be described. In normal operation, as in the first embodiment, in order to control the position of the upper end plate movable portion 62 that is the suction volume control means so that the radiator outlet is on the optimum efficiency pressure line shown in FIG. The control valve 8 and the bypass valve 16 do not operate, the control valve 8 is fully open, and the bypass valve 16 is fully closed. However, when the degree of superheat cannot be ensured in a transient state or overload in winter, the present cycle apparatus performs the same control as that of the first embodiment in order to ensure the degree of superheat. Further, in normal operation, when the radiator outlet becomes higher than the optimum efficiency pressure line shown in FIG. 3, the opening degree of the bypass valve 16 is gradually increased. As a result, even if the maximum suction volume is determined by the suction volume control means 9, it is possible to improve the reliability without excessively increasing the high pressure side.

As described above, according to the present embodiment, the bypass pipe line 15 in which the bypass valve 16 is installed is arranged, and the control valve 8, the suction volume control means 9, and the bypass valve 16 are controlled, so that it can be used in a wide range of refrigeration cycle conditions. Therefore, the heat exchanger can be protected along with the increase in pressure on the high pressure side, and the compressor can be protected by liquid phase compression, so that a highly reliable refrigeration cycle apparatus can be obtained.
(Seventh embodiment)
The expander 3 and the control valve 8 according to the fifth embodiment are sequentially installed in series. Furthermore, a bypass line 15 and a bypass valve 16 are provided as a configuration according to the present invention. This will be described in detail below with reference to the drawings.

  In FIG. 15, the refrigerant circuit figure of the refrigerating-cycle apparatus in this embodiment is shown. The refrigeration cycle apparatus of the present embodiment includes a refrigerant circuit 10 in which a compressor 1, a gas cooler 2, an expander 3, and an evaporator 4 are connected in order, and the compressor 1 and the expander 3 are connected to the electric motor 5. The arrows indicate the direction in which the refrigerant flows. A control valve 8 is provided between the gas cooler 2 and the expander 3. In FIG. 15, the same components as those in FIG. One end of the bypass pipe 15 in which the bypass valve 16 is installed is connected between the radiator 2 and the expander 3, and the other end is connected between the control valve 8 and the evaporator 4.

The operation of the refrigeration cycle of the refrigeration cycle apparatus will be described. In FIG. 15, the compressor 1 is driven by an electric motor 5 controlled by an inverter (not shown), and the refrigerant is compressed by the compressor 1. The compressed refrigerant is cooled by the radiator 2, and then the control valve 8
A circuit that passes through the expander 3 and a pipe that passes through the bypass valve 16 are branched and expanded. The expanded refrigerant absorbs heat from the outside in the evaporator 4 and vaporizes, and then returns to the compressor 1 again.

  The expander-integrated compressor in the present embodiment has the same configuration as the expander-integrated compressor shown in FIG.

  The control method and effects of the control valve 8 and the suction volume control means 9 shown in FIG. 15 will be described. In normal operation, as in the first embodiment, in order to control the position of the upper end plate movable portion 62 that is the suction volume control means so that the radiator outlet is on the optimum efficiency pressure line shown in FIG. The control valve 8 and the bypass valve 16 do not operate, the control valve 8 is fully open, and the bypass valve 16 is fully closed. However, when the degree of superheat cannot be ensured in a transient state or overload in winter, the present cycle apparatus performs the same control as that of the first embodiment in order to ensure the degree of superheat. Further, in normal operation, when the radiator outlet becomes higher than the optimum efficiency pressure line shown in FIG. 3, the opening degree of the bypass valve 16 is gradually increased. As a result, even if the maximum suction volume is determined by the suction volume control means 9, it is possible to improve the reliability without excessively increasing the high pressure side.

As described above, according to the present embodiment, the bypass pipe line 15 in which the bypass valve 16 is installed is arranged, and the control valve 8, the suction volume control means 9, and the bypass valve 16 are controlled, so that it can be used in a wide range of refrigeration cycle conditions. Therefore, the heat exchanger can be protected along with the increase in pressure on the high pressure side, and the compressor can be protected by liquid phase compression, so that a highly reliable refrigeration cycle apparatus can be obtained.
(Eighth embodiment)
Although the control valve 8 according to the third embodiment is installed after the bypass pipe 15 and the suction path to the expander are branched, the control valve 8 is branched between the bypass pipe 15 and the suction path to the expander. It may be installed in front.

In FIG. 16, the refrigerant circuit figure of the refrigerating-cycle apparatus in this embodiment is shown. The refrigeration cycle apparatus of the present embodiment includes a refrigerant circuit 10 in which a compressor 1, a gas cooler 2, an expander 3, and an evaporator 4 are connected in order, and the compressor 1 and the expander 3 are connected to the electric motor 5. The arrows indicate the direction in which the refrigerant flows. A control valve 8 is provided between the gas cooler 2 and the expander 3. In FIG. 16, the same components as those in FIG. One end of the bypass pipe 15 in which the bypass valve 16 is installed is connected between the control valve 8 and the expander 3, and the other end is connected between the expander 3 and the evaporator 4. Other configurations and control methods are the same as those in the third embodiment.
(Ninth embodiment)
The control valve 8 according to the fourth embodiment is installed before the bypass pipe 15 and the suction path from the expander are merged, but is installed after the bypass pipe 15 and the suction path from the expander are merged. May be.

  In FIG. 17, the refrigerant circuit figure of the refrigerating-cycle apparatus in this embodiment is shown. The refrigeration cycle apparatus of the present embodiment includes a refrigerant circuit 10 in which a compressor 1, a gas cooler 2, an expander 3, and an evaporator 4 are connected in order, and the compressor 1 and the expander 3 are connected to the electric motor 5. The arrows indicate the direction in which the refrigerant flows. A control valve 8 is provided between the gas cooler 2 and the expander 3. In FIG. 17, the same components as those in FIG. One end of the bypass pipe 15 in which the bypass valve 16 is installed is connected between the radiator 2 and the expander 3, and the other end is connected between the expander 3 and the control valve 8. Other configurations and control methods are the same as those in the fourth embodiment.

  As described above, the refrigeration cycle apparatus using the expander of the present invention improves not only the high-efficiency refrigeration cycle by the expander provided with the suction volume control means but also the reliability and responsiveness without destruction of components. It has an effect and is useful for a heat pump refrigeration apparatus such as an air conditioner or a water heater.

The block block diagram which shows the refrigerating-cycle apparatus of 1st Embodiment by this invention. The figure which shows the relationship of the volume ratio at the time of the suction | inhalation volume change of 1st Embodiment by this invention. The figure which shows an example of the efficiency of the refrigerating cycle with respect to radiator outlet pressure and temperature Mollier diagram in the first embodiment of the present invention Flow chart of control valve and suction volume control means control Characteristic diagram showing control timing of suction volume and control valve controlled by suction volume control means An expander-integrated compressor provided with suction volume control means according to the first embodiment of the present invention (A) Perspective view of upper end plate fixing portion of expander in FIG. 7 (b) Perspective view of upper end plate movable portion of expander in FIG. 7 (c) Perspective view of upper end plate of expander in FIG. (A) An enlarged cross-sectional view of the D1-D1 cross section of the expander of the expander-integrated compressor of FIG. 7 at φ = 20 deg. (B) D1 of the expander of the expander-integrated compressor of FIG. 7 at φ = 90 deg. -D1 cross-sectional enlarged view (A) Diagram showing suction / discharge volume at the suction volume control means position (b) Diagram showing volume ratio at the suction volume control means position Refrigerant circuit diagram of the refrigeration cycle apparatus in the first embodiment of the present invention using a four-way valve The block block diagram which shows the refrigerating cycle apparatus of 1st Embodiment by this invention using a pressure detection means. The block block diagram which shows the refrigerating-cycle apparatus of 5th Embodiment by this invention. The block block diagram which shows the refrigerating-cycle apparatus of the 6th Embodiment by this invention. The block block diagram which shows the refrigerating-cycle apparatus of 7th Embodiment by this invention. The block block diagram which shows the refrigerating-cycle apparatus of 8th Embodiment by this invention. The block block diagram which shows the refrigerating-cycle apparatus of 9th Embodiment by this invention. Block diagram showing the expander-integrated compressor and bypass circuit Mollier diagram showing power recovery by expander

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Radiator 3 Expander 4 Evaporator 5 Electric motor 6 Shaft 7 Refrigerant piping 8 Control valve 9 Suction volume control means 15 Bypass pipe 16 Bypass valve 61 Upper end plate fixed part 62 Upper end plate movable part

Claims (10)

A positive displacement compressor that compresses the working fluid;
A radiator for cooling the refrigerant compressed by the compressor;
A positive displacement expander for expanding the working fluid;
An evaporator for evaporating the refrigerant expanded by the expander;
An electric motor that connects the compressor and the expander uniaxially in an airtight container;
A refrigerant pipe connected to the compressor, the radiator, the expander, and the evaporator in order and circulating a refrigerant;
A suction volume control means capable of changing the suction volume of the refrigerant flowing into the expander on the suction side of the expander;
A refrigeration cycle apparatus having a control valve for expanding the refrigerant connected in series with the expander   The refrigeration cycle apparatus according to claim 1, wherein the control valve is disposed upstream of the expander having the suction volume control means. A first temperature detecting means attached to either the outlet side of the expander or in the evaporator, for detecting the temperature of the refrigerant;
A second temperature detecting means attached between the outlet of the evaporator and the inlet of the compressor and detecting the temperature of the refrigerant;
A first control unit that controls using signals from the first temperature detection unit and the second temperature detection unit;
The suction volume control means and the control valve are controlled by a signal from the control unit, the supply amount of the refrigerant is changed, and the superheat degree at the evaporator outlet or the compressor inlet is controlled to a predetermined value. The refrigeration cycle apparatus according to any one of claims 1 to 2. A pressure detecting means attached between the outlet of the expander and the inlet of the compressor, for detecting the pressure of the refrigerant;
A second temperature detecting means attached between the outlet of the evaporator and the inlet of the compressor for detecting the temperature of the refrigerant;
A second control unit that controls using signals from the pressure detection means and the second temperature detection means;
The suction volume control means and the control valve are controlled by a signal from the control unit, the supply amount of the refrigerant is changed, and the superheat degree at the evaporator outlet or the compressor inlet is controlled to a predetermined value. The refrigeration cycle apparatus according to any one of claims 1 to 2.   5. The refrigeration cycle apparatus according to claim 1, wherein an intake volume of the refrigerant flowing into the expander by the intake volume control means is equal to or greater than an original design intake volume of the expander.   When the degree of heating is smaller than a predetermined value, the first or second control unit sets the superheat degree when the suction volume control means minimizes the suction volume of the refrigerant flowing into the expander by the suction volume control means. The refrigeration cycle apparatus according to any one of claims 3 to 5, wherein the control valve is controlled to control to a predetermined value.   The first or second control unit is a minimum suction volume that minimizes the suction volume of the refrigerant flowing into the expander by the suction volume control means. When the opening degree of the control valve is not the maximum, the degree of superheat is set. The refrigeration cycle apparatus according to any one of claims 3 to 6, wherein the control valve is controlled to control to a predetermined value.   The said electric motor is driven at the time of the said refrigerating cycle start, The said suction volume control means is controlled by the said 1st or 2nd control part, and it set to the minimum suction volume. Refrigeration cycle equipment   The said electric motor is driven at the time of the said refrigerating cycle start, The said control valve is controlled by the said 1st or 2nd control part, The pressure of the refrigerant | coolant of a high voltage | pressure side is controlled to a predetermined pressure. The refrigeration cycle apparatus according to any one of (The suction volume variable means is the volume variable means)
The refrigeration cycle apparatus according to any one of claims 1 to 9, wherein the suction volume control means is a volume variable means capable of changing a refrigerant suction volume of an expander.

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