JP2016133238A - Heat pump cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump cycle device restricting vibration of an injection piping and having a degree of freedom improved.SOLUTION: A heat pump cycle device 100 connects between a water refrigerant heat exchanger 3 and a first expansion valve 4 and connects with an intermediate pressure part of a compressor 1 and has an injection piping 14 having a second expansion valve 22 and a capillary tube 23 assembled in series. The injection piping 14 has a bypass pipe 15 bypassing the capillary tube 23 and is provided with a solenoid valve 21. Control means 60 closes the solenoid valve 21 when a refrigerant circuit is energized as a heating cycle, performs a starting time injection control with the second expansion valve 22 being set to have a minimum opening degree, and when the refrigerant circuit is being operated as the heating cycle, opens and closes the solenoid valve 21 in reference to the expansion valve/solenoid valve control table and at the same time performs an operation time injection control for adjusting a degree of opening of the second expansion valve 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat pump cycle device, and more particularly to a heat pump cycle device capable of injecting liquid refrigerant into an intermediate pressure portion of a compressor.

  Conventionally, as a heat pump cycle apparatus, an air conditioner is a typical apparatus, and in order to suppress an increase in the refrigerant discharge refrigerant temperature, liquid refrigerant is injected into an intermediate pressure portion of the compressor (hereinafter referred to as liquid injection). The one provided with the injection pipe to be described is proposed (for example, Patent Document 1).

  The air conditioner disclosed in Patent Document 1 includes a refrigerant circuit in which a compressor, a four-way valve, a use side heat exchanger, an expansion valve, and a heat source side heat exchanger are sequentially connected by a refrigerant pipe. An injection pipe provided with an expansion valve is provided by branching from a refrigerant pipe connecting the use side heat exchanger and the expansion valve and connected to an intermediate pressure portion of the compressor.

  On the other hand, it is one of the heat pump cycle devices, and is a water-refrigerant heat exchanger in which the use side heat exchanger exchanges heat between water and refrigerant, such as a heat pump hot / cold water air conditioner and a heat pump hot water supply device. There is a heat pump cycle device that generates hot water by heat exchange with a refrigerant. Also in such a heat pump cycle apparatus, what provided the injection piping provided with the expansion valve in order to perform liquid injection to a compressor is proposed.

  In general, the heat pump cycle device protects the discharge refrigerant temperature when the discharge refrigerant temperature of the compressor rises due to the high compression ratio operation, such as when heating operation or hot water supply operation is performed at a low outside air temperature (0 ° C. or less). There is a possibility that the compressor will frequently stop / restart due to the control, and there is a possibility that stable heat pump cycle apparatus cannot be operated.

  In a heat pump cycle device equipped with an injection pipe, the expansion valve provided in the injection pipe is opened at a predetermined opening in order to suppress an increase in the discharge refrigerant temperature during a heating operation or a hot water supply operation, and the use side heat exchanger Alternatively, a part of the liquid refrigerant condensed by the water refrigerant heat exchanger is injected into the intermediate pressure portion of the compressor. In this way, by performing liquid injection on the compressor to cool the inside of the compressor, an increase in the discharge refrigerant temperature of the compressor can be suppressed, so that the compressor is frequently stopped / restarted by the discharge refrigerant temperature protection control. Starting is prevented and the operation of the heat pump cycle device can be performed stably.

JP-A-8-210709 (pages 4-6, FIG. 2)

  In the heat pump cycle device capable of performing liquid injection as described above, generally, when starting the compressor when starting the heating operation, the expansion valve is fully closed to interrupt the flow of the refrigerant in the injection pipe, that is, Do not inject liquid into the compressor. When the compressor is started, the amount of refrigerating machine oil inside the compressor is temporarily reduced by discharging the refrigerating machine oil together with the refrigerant. This is because if the liquid refrigerant is injected into the compressor by liquid injection in this state, the refrigeration oil is diluted and the mechanical portion of the compressor becomes insufficiently lubricated.

  Further, even when the heat pump cycle device is in a heating operation and the compressor is driven at a low rotation due to a low heating load, liquid injection to the compressor is not performed. When the compressor is driven at a low speed, the temperature inside the compressor does not increase and the discharge refrigerant temperature does not rise, so there is no need to cool the compressor inside (the discharge refrigerant temperature protection control works frequently. This is because the compressor is not stopped / restarted), and the internal temperature of the compressor is prevented from lowering more than necessary by performing a large amount of liquid injection in this state.

  However, if the expansion valve is fully closed and the refrigerant flow in the injection pipe is blocked, the operation of the compressor causes the inside of the injection pipe (the connection between the injection pipe connection port of the compressor and the expansion valve in the injection pipe). Pressure fluctuation may occur during this period, which may cause vibration of the injection piping.

  In particular, when the compressor is a rotary compressor, the pressure inside the injection pipe of the compressor repeatedly increases / decreases due to the rotation of the rotor of the mechanical unit (if the rotor comes near the injection pipe connection port, the pressure inside the injection pipe) When the rotor is moved away from the injection pipe connection port, the pressure inside the injection pipe is lowered), causing vibration of the injection pipe, and noise due to the vibration of the injection pipe. In addition, there is a problem that the reliability of the connection portion of the injection pipe decreases due to the vibration of the injection pipe.

  In order to suppress the vibration of the injection pipe described above, as an expansion valve provided in the injection pipe, it does not cause dilution of refrigeration oil at the time of starting the compressor or excessive decrease in the internal temperature of the compressor during operation during heating operation. Select an opening that allows a very small amount of liquid refrigerant to flow, and open the expansion valve to allow the above-mentioned small amount of liquid refrigerant to flow when the compressor is started during heating operation or when the compressor is driven at a low speed. It is also conceivable that the pressure fluctuation in the injection pipe is suppressed by allowing the refrigerant to flow through the injection pipe. However, the expansion valve generally has a problem that it is difficult to flow a very small amount of refrigerant stably. In addition, in order to achieve an opening that allows a very small amount of liquid refrigerant to flow, an expansion valve with a large nominal diameter is difficult to use, and the selection range of the expansion valve is narrowed, which reduces the design flexibility of the heat pump cycle device. .

  An object of the present invention is to solve the above-described problems, and to provide a heat pump cycle device that suppresses vibration of injection piping and improves design flexibility.

  This invention solves the above-mentioned subject, The heat pump cycle device of this invention connects a compressor, a use side heat exchanger, a 1st expansion valve, and a heat source side heat exchanger in order with refrigerant piping, Injection pipe in which one end is connected between the water-refrigerant heat exchanger and the first expansion valve in the refrigerant pipe and the other end is connected to the intermediate pressure portion of the compressor, and the flow rate regulating means and the second expansion valve are incorporated in series. A refrigerant circuit, a condensing pressure detecting means, and a control means for controlling the rotational speed of the compressor, and the injection pipe includes a bypass pipe that bypasses the flow rate regulating means and includes an opening / closing means. Is provided. And when the control means starts the refrigerant circuit as a heating cycle, the control means closes the opening / closing means until the temperature of the compressor reaches a predetermined temperature, and the refrigerant after the temperature of the compressor reaches the predetermined temperature. When the circuit is operated as a heating cycle, opening / closing control of the opening / closing means is performed according to the condensing pressure detected by the condensing pressure detecting means and the rotational speed of the compressor.

  The heat pump cycle device of the present invention can suppress vibration caused by pressure fluctuation inside the injection pipe during startup in a heating cycle or during heating operation.

It is a lineblock diagram of a heat pump cycle device in an embodiment of the present invention. It is an expansion valve / solenoid valve control table in the embodiment of the present invention. It is a flowchart explaining the flow of the process regarding the main routine performed by the control means in embodiment of this invention. It is a flowchart explaining the flow of the process regarding the injection control at the time of starting which is one of the subroutines in embodiment of this invention. It is a flowchart explaining the flow of the process regarding the injection control during driving | operation which is one of the subroutines in embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an embodiment, a heat pump cycle device having an indoor unit such as a floor heating device or a radiator and performing heat exchange between water and refrigerant in a water refrigerant heat exchanger will be described as an example. The present invention is not limited to the following embodiments, and can be variously modified without departing from the gist of the present invention.

  FIG. 1 shows a configuration of a heat pump cycle apparatus according to the present invention. The heat pump cycle apparatus 100 includes a rotary compressor 1 (hereinafter referred to as a compressor 1), a four-way valve 2, a water-refrigerant heat exchanger 3 that is a use-side heat exchanger that performs heat exchange between refrigerant and water, 1 expansion valve 4, heat source side heat exchanger 5 and accumulator 6 are connected in order by refrigerant piping 11, and refrigerant circuit 10 is constituted, and it is constituted so that the refrigerant circulation direction in refrigerant circuit 10 may be switched by four-way valve 2. Yes.

  One end of the refrigerant circuit 10 is connected between the water refrigerant heat exchanger 3 and the first expansion valve 4 in the refrigerant pipe 11, and the other end is connected to the intermediate pressure part 1 a of the compressor 1. An injection pipe 14 in which a tube 23 and a second expansion valve 22 are incorporated in series is provided. In addition, a bypass pipe 15 having an electromagnetic valve 21 as an opening / closing means is connected to both ends of the capillary tube 23.

  The first expansion valve 4 and the second expansion valve 22 use a stepping motor to enable pulse control of the valve opening. In addition, the capillary tube 23 is selected such that when the second expansion valve 22 is at the minimum opening, a flow amount of refrigerant smaller than the amount of refrigerant passing through the second expansion valve 22 is selected. For example, the heat pump cycle device 100 is heated. When starting up by operation, the amount of liquid refrigerant injected into the compressor 1 by the capillary tube 23 and the second expansion valve 22 having the minimum opening is extremely small so that the refrigerating machine oil of the compressor 1 is diluted very little. A small amount is selected.

  A discharge refrigerant temperature sensor 51 for detecting the temperature of refrigerant discharged from the compressor 1 (discharge refrigerant temperature) is provided near the discharge port of the compressor 1 in the refrigerant pipe 11. A compressor temperature sensor 52 for detecting the temperature of the compressor 1 is provided below the sealed container of the compressor 1.

  Between the water-refrigerant heat exchanger 3 and the first expansion valve 4 in the refrigerant pipe 11, a refrigerant temperature sensor 53 that detects the refrigerant temperature in the vicinity of the first expansion valve 4 is also provided. Between the heat source side heat exchanger 5 and the heat source side heat exchanger 5, a heat exchange temperature sensor 54 for detecting the temperature of the heat source side heat exchanger 5 is provided.

  In the vicinity of the heat source side heat exchanger 5, an outside air temperature sensor 55 for detecting the outside air temperature is provided. Further, a pressure sensor 50 serving as a condensation pressure detecting means is provided on the refrigerant pipe 11 on the discharge side of the compressor 1 (between the four-way valve 2 and the water refrigerant heat exchanger 3).

  The water refrigerant heat exchanger 3 is connected to the refrigerant pipe 11 and the water pipe 16, and the water pipe 16 is provided with a circulation pump 30 for circulating water through the indoor unit 40. The water exchanged with the refrigerant is configured to circulate in the direction of the arrow 80 shown in FIG. A return temperature sensor 56 for detecting the temperature of the water flowing into the water refrigerant heat exchanger 3 is provided on the water inlet side of the water refrigerant heat exchanger 3 in the water pipe 16. 3 is provided with a forward temperature sensor 57 for detecting the temperature of water flowing out of the water-refrigerant heat exchanger 3.

  In addition to the configuration described above, the heat pump cycle apparatus 100 is provided with a control means 60. The control means 60 inputs the temperature detected by each temperature sensor and the condensing pressure detected by the pressure sensor 50, or the compressor 1 and the circulation pump 30 according to the operation request from the user by a remote controller (not shown). The heat pump cycle device 100 is controlled such as drive control, switching control of the four-way valve 2, opening / closing control of the electromagnetic valve 21, opening adjustment of the first expansion valve 4 and the second expansion valve 22, and the like.

  In FIG. 1, when the heat pump cycle device 100 is operated with the refrigerant circuit 10 operated as a heating cycle, the refrigerant flow direction is indicated by an arrow 70, the second expansion valve 22 is set to a predetermined opening, and the refrigerant flows into the injection pipe 14. The refrigerant flow direction in each case is indicated by arrows 90. In the heat pump cycle device 100, the refrigerant flow direction when the refrigerant circuit 10 is operated as a cooling cycle is the refrigerant flow direction when the refrigerant circuit 10 is operated as a heating cycle except between the compressor 1 and the four-way valve 2 (arrow 70). The direction of the refrigerant flow during the cooling cycle is omitted. Further, when the refrigerant circuit 10 is operated as a cooling cycle, the second expansion valve 22 is fully closed. During the cooling cycle, the level of pressure at both ends of the injection pipe 14 is opposite to that during heating operation. That is, the pressure on the compressor 1 side in the injection pipe 14 is higher than the pressure on the connection side with the refrigerant pipe 11. In this state, since the refrigerant flows in the injection pipe 14 from the intermediate pressure portion 1a of the compressor 1 toward the refrigerant pipe 11, the second expansion valve 22 is fully closed to prevent this.

  Next, the operation | movement of the refrigerant circuit 10 and its effect | action and effect in the heat pump cycle apparatus 100 of this invention are demonstrated using FIG. 1 and FIG. In the following description, the case where the heat pump cycle apparatus 100 performs the heating operation, that is, the case where the refrigerant circuit 10 operates as the heating cycle will be described as an example.

  An expansion valve / electromagnetic valve control table 200 shown in FIG. 2 is stored in a storage unit (not shown) of the control means 60. This expansion valve / solenoid valve control table 200 is for performing injection control during operation, which will be described later, and controls the opening / closing of the solenoid valve 21 and the second expansion valve 22 when the refrigerant circuit 10 is operated as a heating cycle. This is for adjusting the opening degree. The expansion valve / solenoid valve control table 200 is created in advance based on the confirmation result of a test or the like and stored in the control means 60.

  The expansion valve / solenoid valve control table 200 corresponds to the condensing pressure detected by the pressure sensor 50 (hereinafter referred to as condensing pressure HP) and the rotational speed of the compressor 1 (hereinafter referred to as compressor rotational speed F). The opening / closing of the electromagnetic valve 21 and the opening of the second expansion valve 22 are determined. Since the opening degree of the second expansion valve 22 is controlled by the stepping motor as described above, the expansion valve / solenoid valve control table 200 includes the second expansion valve at each condensing pressure HP and the compressor rotational speed F. The number of pulses (unit: P) applied to the stepping motor corresponding to the opening of 22 is determined. Further, the relationship between the opening of the second expansion valve 22 and the number of pulses indicates that the minimum opening of the second expansion valve 22 (the amount of refrigerant passing through the second expansion valve 22 is the minimum amount) when the number of pulses is 50P. Opening degree), and when the number of pulses is 500 P, the maximum opening degree (the opening degree at which the amount of refrigerant passing through the second expansion valve 22 becomes the maximum amount) is obtained. When the number of pulses is 0P, the second expansion valve 22 is fully closed (a state in which refrigerant cannot pass through the second expansion valve 22). The compressor speed F is controlled by the control means 60, and the control means 60 stores the current compressor speed F in the storage unit and updates it every time the compressor speed F is changed. Yes.

  For example, since the required operating capacity is high during heating operation at a low outside air temperature, it is necessary to increase the refrigerant flow rate in the water-refrigerant heat exchanger 3 by increasing the rotation speed of the compressor 1. However, when the rotation speed of the compressor 1 is increased, the internal temperature of the compressor 1 increases and the discharge pressure of the compressor 1 may approach the performance upper limit value. Therefore, by performing liquid injection on the compressor 1, the compressor 1 is cooled, and the refrigerant flow rate in the water refrigerant heat exchanger 3 is also increased by the refrigerant returning from the injection pipe 14 to the compressor 1. On the other hand, when the amount of liquid injection is too large, the internal temperature of the compressor 1 is unnecessarily lowered and the refrigerating machine oil of the compressor 1 is diluted by the liquid refrigerant, which may cause poor lubrication of the compressor 1.

  In the expansion valve / solenoid valve control table 200 of this embodiment, the above-described increase in the internal temperature of the compressor 1 is adjusted, the refrigerant flow rate in the water refrigerant heat exchanger 3 is adjusted, and the compressor 1 by liquid injection is used. In order to prevent the occurrence of poor lubrication, the opening / closing of the electromagnetic valve 21 and the opening of the second expansion valve 22 are determined in association with the condensation pressure HP and the compressor rotational speed F. Note that the opening degree of the second expansion valve 22 is determined in advance by a test or the like.

  In the expansion valve / solenoid valve control table 200, when the condensing pressure HP is 3.5 MPa or more, the compressor speed F is less than 30 rps, the solenoid valve is closed, and the number of pulses is 50 P (corresponding to the minimum opening). It has been. Further, the solenoid valve is opened and the number of pulses is set to 200 P when the compressor rotational speed F is 30 rps or more and less than 50 rps. Further, the solenoid valve is opened and the number of pulses is set to 350 P when the compressor rotation speed F is 50 rps or more and less than 70 rps. When the compressor rotational speed F is 70 rps or higher, the solenoid valve is opened and the number of pulses is 500 P (corresponding to the maximum opening).

  When the condensation pressure HP is 3.5 MPa or more, the discharge pressure of the compressor 1 is likely to reach the upper limit of performance, and the discharge pressure of the compressor 1 increases as the compressor rotation speed F increases. Therefore, when the condensing pressure HP is 3.5 MPa or more and the compressor rotational speed F is 30 rps or more, the amount of liquid refrigerant flowing through the injection pipe 14 and injected into the intermediate pressure portion 1a of the compressor 1 is increased and compressed. The number of pulses is determined so that the opening degree of the second expansion valve 22 increases as the compressor speed F increases so as to cool the machine 1 and suppress the increase in discharge pressure.

  When the compressor rotational speed F is less than 30 rps, the electromagnetic valve 21 is determined to be closed, and the number of pulses applied to the second expansion valve 22 is set to 50P, and the second expansion valve 22 is determined to be the minimum opening. . This is because, even when the condensation pressure HP is 3.5 MPa or more, it is less likely that the discharge pressure of the compressor 1 will reach the upper limit of the performance than when the compressor rotation speed F is 30 rps or more, and the compression In consideration of preventing the internal temperature of the machine 1 from being lowered more than necessary and preventing the refrigerant oil of the compressor 1 from being diluted by the liquid refrigerant to cause poor lubrication of the compressor 1, the first opening is set to the minimum. This is because the amount of liquid refrigerant injected into the intermediate pressure portion 1a of the compressor 1 by the two expansion valve 22 and the capillary tube 23 is minimized.

  Similarly to the above, when the condensing pressure HP is 2.5 MPa or more and less than 3.0 MPa, or when the condensation pressure HP is 3.0 MPa or more and less than 3.5 MPa, the opening / closing control of the electromagnetic valve 21 is performed according to the compressor rotational speed F. The number of pulses corresponding to the opening of the second expansion valve 22 is determined to be a liquid injection amount that cools the compressor 1 and suppresses an increase in discharge pressure. Here again, when it is considered that the discharge pressure of the compressor 1 is unlikely to reach the upper limit of performance, or when the internal temperature of the compressor 1 is unnecessarily lowered, the refrigeration oil is diluted with liquid refrigerant and the compressor 1 If there is a risk of poor lubrication, the solenoid valve 21 is closed and the number of pulses applied to the second expansion valve 22 is set to 50 P, and the second expansion valve 22 is set to the minimum opening, so The amount of liquid refrigerant injected into the pressure part 1a is minimized.

  When the condensation pressure HP is less than 2.5 MPa, all the solenoid valves 21 are closed and the number of pulses is set to 50P regardless of the compressor rotation speed F. When the condensation pressure HP is less than 2.5 MPa, the possibility that the discharge pressure of the compressor 1 reaches the upper limit of performance is low regardless of the compressor rotation speed F. Accordingly, in consideration of preventing the internal temperature of the compressor 1 from being lowered more than necessary and preventing the refrigerant oil of the compressor 1 from being diluted by the liquid refrigerant to cause poor lubrication of the compressor 1, Regardless of the number F, the solenoid valve 21 is closed and the number of pulses applied to the second expansion valve 22 is set to 50 P, and the second expansion valve 22 is set to the minimum opening, so that it is injected into the intermediate pressure part 1 a of the compressor 1. The amount of liquid refrigerant is extremely small.

  Next, a specific operation of the heat pump cycle apparatus 100 will be described. When the user operates a remote controller (not shown) of the indoor unit 40 to instruct the start of heating operation, the control means 60 rotates the circulation pump 30 to supply water between the water / refrigerant heat exchanger 3 and the indoor unit 40. While circulating, the four-way valve 2 is switched so that the refrigerant circuit 10 becomes a heating cycle, the compressor 1 is started, and the heating operation of the heat pump cycle apparatus 100 is started. When the heat pump cycle device 100 starts the heating operation, the electromagnetic valve 21 is opened and the second expansion valve 22 is fully closed.

  The control means 60 closes the electromagnetic valve 21 and sets the second expansion valve 22 to the minimum opening (the second expansion valve 22) unless a start-up injection control end condition to be described later is satisfied when the heating operation is started. The injection control at the time of starting is performed. The start-up injection control is a control for injecting a very small amount of liquid into the compressor 1 when the compressor 1 is started after the heating operation is started. The electromagnetic valve 21 is closed and the second expansion valve 22 is opened to the minimum. By setting the degree, the amount of liquid refrigerant injected into the intermediate pressure part 1a of the compressor 1 by the second expansion valve 22 and the capillary tube 23 having the minimum opening becomes a very small amount.

  As described in the background art, it is difficult to stably flow a very small amount of refrigerant even when the expansion valve (in this case, the second expansion valve 22) is set to the minimum opening. On the other hand, the capillary tube 23 can stably distribute a certain amount of refrigerant. Therefore, in the injection control at the time of startup, the capillary tube 23 in which a smaller amount of refrigerant passes through the second expansion valve 22 when the minimum opening is reached, and the second expansion valve 22 having the minimum opening. A very small amount of liquid injection can be stably performed in the compressor 1.

  At this time, since the injection pipe 14 is in a state in which a very small amount of refrigerant flows through the second expansion valve 22 and the capillary tube 23 set to the minimum opening degree, the injection pipe 14 has an inside of the injection pipe 14 caused by the rotation of the rotor of the compressor 1. The pressure fluctuation is reduced, and the vibration of the injection pipe 14 due to this can be suppressed. In addition, since only a very small amount of liquid is injected into the compressor 1 by the second expansion valve 22 and the capillary tube 23 having the minimum opening, a large amount of liquid refrigerant is injected when the compressor 1 is started. It is possible to prevent the refrigeration oil from being diluted and the mechanical portion of the compressor 1 from being poorly lubricated.

  The control means 60 performs the start-up injection control until a start-up injection control end condition described below is satisfied. The start-up injection control end condition is that the internal temperature of the compressor 1 rises and the liquid refrigerant existing in the compressor 1 reaches a predetermined temperature at which it becomes a gas refrigerant, so that the refrigerant discharged from the compressor 1 This is a condition that the amount of the refrigerating machine oil taken out of the compressor 1 is reduced, or the dilution of the refrigerating machine oil by the liquid refrigerant condensed inside the compressor 1 is reduced. The control means 60 determines that the difference between the discharge refrigerant temperature detected by the discharge refrigerant temperature sensor 51 and the condensation temperature in the water refrigerant heat exchanger 3 calculated from the condensation pressure detected by the pressure sensor 50 is a predetermined value or more (for example, 10 If the difference between the temperature of the compressor 1 detected by the compressor temperature sensor 52 and the condensation temperature is a predetermined value or more (for example, 5 ° C. or more), the internal temperature of the compressor 1 is The amount of the refrigeration oil that rises and is taken out of the compressor 1 by the refrigerant reaches a predetermined temperature, or the dilution of the refrigeration oil by the liquid refrigerant condensed inside the compressor 1 is reduced, that is, injection at startup It is determined that the control end condition is satisfied. Each temperature difference is obtained in advance by a test or the like and stored in the storage unit of the control means 60.

  If the start-up injection control end condition is satisfied, the control means 60 ends the start-up injection control and shifts to normal heating operation control. Specifically, the control means 60 determines that the current water temperature detected by the forward temperature sensor 57, that is, the temperature of the water heated by the water-refrigerant heat exchanger 3, is the target temperature for heating operation set by the user. The drive control of the compressor 1 is performed so that the temperature of water corresponds to a certain set temperature. The refrigerant discharged from the compressor 1 passes through the four-way valve 2, condenses by exchanging heat with water in the water refrigerant heat exchanger 3, is further decompressed by the first expansion valve 4, and is outside air in the heat source side heat exchanger 5. The process of evaporating and evaporating and compressing again with the compressor 1 is repeated. Note that the state of the solenoid valve 21 and the second expansion valve 22 when the start-up injection control is finished is the same as when the start-up injection control is being performed (the solenoid valve 21 is closed and the second expansion valve 22 is minimum open). Degree).

  The control means 60 performs the injection control during operation while performing the heating operation control. Specifically, the control means 60 takes in the condensing pressure detected by the pressure sensor 50, converts the condensing pressure taken in with reference to the expansion valve / electromagnetic valve control table 200, and the compressor rotational speed F read out from the storage unit. Correspondingly, the number of pulses applied to the opening / closing of the electromagnetic valve 21 and the stepping motor of the second expansion valve 22 is extracted. The control means 60 opens or closes the electromagnetic valve 21 according to the opening / closing of the extracted electromagnetic valve 21. Further, the control means 60 adds a pulse signal corresponding to the extracted number of pulses to the stepping motor of the second expansion valve 22 and sets the opening of the second expansion valve 22 to an opening corresponding to the number of pulses. Thus, an amount of liquid refrigerant corresponding to the opening of the second expansion valve 22 is injected into the intermediate pressure portion 1a of the compressor 1.

  As shown in the expansion valve / electromagnetic valve control table 200, when the condensing pressure HP and the compressor rotational speed F are low, the electromagnetic valve 21 is determined to be closed and the number of pulses is determined to be 50P. At this time, as in the case of the start-up injection control that is performed when the compressor 1 is started, the capillary tube 23 in which a smaller amount of refrigerant flows than the amount of refrigerant that passes through the second expansion valve 22 when the opening degree is the minimum. Then, the second expansion valve 22 having the minimum opening allows a very small amount of liquid injection to be stably performed in the compressor 1.

  At this time, since the injection pipe 14 is in a state in which a very small amount of refrigerant flows through the second expansion valve 22 and the capillary tube 23 set to the minimum opening degree, the injection pipe 14 has an inside of the injection pipe 14 caused by the rotation of the rotor of the compressor 1. The pressure fluctuation is reduced, and the vibration of the injection pipe 14 due to this can be suppressed. Further, since the compressor 1 can perform only a very small amount of liquid injection by the minimum expansion opening 22 and the capillary tube 23, the dilution of the refrigerating machine oil inside the compressor 1 is negligible. Occurrence of poor lubrication of the compressor 1 due to a decrease in the viscosity of the refrigeration oil can be suppressed. Moreover, by setting it as a very small amount of liquid injection, the compressor 1 is not cooled more than necessary, and the fall of the heating capability by the internal temperature fall of the compressor 1 can be minimized.

  In the embodiment described above, the case where the condensation pressure is detected by the pressure sensor 50 has been described. However, the present invention is not limited to this. For example, the water refrigerant heat exchanger 3 is provided with a temperature sensor. 3 may be detected, and the condensation pressure may be calculated from the detected condensation temperature.

  Next, processing related to the heat pump cycle apparatus 100 of the present invention will be described using the flowcharts shown in FIGS. 3 is a main routine of the heat pump cycle apparatus 100, FIG. 4 is a subroutine showing the injection control at the start of the heat pump cycle apparatus 100, and FIG. 5 is a subroutine showing the injection control at the time of operation of the heat pump cycle apparatus 100. In each of these drawings, ST represents a step, and the number following this represents a step number. In addition, in FIG.3 and FIG.4, it demonstrated centering on the process in connection with this invention, for example, control according to operation conditions, such as setting temperature which the user instruct | indicated at the time of heating operation, such as, Description of general processing related to the heat pump cycle apparatus 100 is omitted.

  First, the flow of processing relating to the main routine of the heat pump cycle apparatus 100 will be described with reference to FIG. As shown in FIG. 3, when the heat pump cycle apparatus 100 starts operation, the control means 60 determines whether or not the operation mode requested by the user is heating operation (ST1). When the required operation mode is the heating operation (ST1-Yes), the control means 60 maintains the state when the refrigerant circuit 10 is in the heating cycle, and four-way when the cooling circuit is in the cooling cycle. The refrigerant circuit 10 is switched to the heating cycle by switching the valve 2.

  Next, the control means 60 performs startup injection control (ST2). When the startup injection control is completed, the control means 60 performs the driving injection control (ST3).

  Next, the control means 60 determines whether or not there is an operation end instruction for the heat pump cycle apparatus 100 (ST4). If there is no operation end instruction (ST4-No), the control means 60 returns the process to ST1, and if there is an operation end instruction (ST4-Yes), the control means 60 ends the process and stops the heat pump cycle apparatus 100.

  In ST1, when the required operation mode is not the heating operation (ST1-No), that is, in the case of the cooling operation or the defrosting operation, the control means 60 is in the case where the refrigerant circuit 10 is in the cooling cycle. Maintains that state, and when it is in the heating cycle, the four-way valve 2 is switched to set the refrigerant circuit 10 to the cooling cycle. Next, the control means 60 fully closes the 2nd expansion valve 22, or maintains the state which is fully closed (ST5). And the control means 60 performs control regarding a cooling operation or a defrost operation (ST6), and advances a process to ST4.

  Next, the flow of processing when performing start-up injection control, which is one of the subroutines of the heat pump cycle apparatus 100, will be described with reference to FIG. When performing the injection control at start-up, the control means 60 takes in the condensation pressure HP detected by the pressure sensor 50, and calculates the condensation temperature using the taken-in condensation pressure HP (ST21). Further, the control means 60 takes in the discharge refrigerant temperature of the compressor 1 detected by the discharge refrigerant temperature sensor 51 or the temperature of the compressor 1 detected by the compressor temperature sensor 52 (ST22).

  Next, the control means 60 uses the calculated condensing temperature and the intake refrigerant temperature of the compressor 1 taken in or the temperature of the compressor 1 to determine whether the difference between the discharge refrigerant temperature and the condensing temperature is a predetermined value or more. Alternatively, it is determined whether the difference between the temperature of the compressor 1 and the condensation pressure is equal to or greater than a predetermined value. In other words, it is determined whether or not the start condition for starting injection control is satisfied (ST23).

  If the end condition of the start-up injection control is satisfied (ST23-Yes), the control means 60 ends the start-up injection control. If the start condition for starting injection control is not satisfied (ST23-No), the control means 60 sets the second expansion valve 22 to the minimum opening (ST24) and closes the electromagnetic valve 21 (ST25). And the control means 60 returns a process to ST21.

  Next, the flow of processing when performing in-operation injection control, which is one of the subroutines of the heat pump cycle apparatus 100, will be described using FIG. When performing the injection control during operation, the control means 60 takes in the condensation pressure HP detected by the pressure sensor 50 (ST31), and reads out the compressor rotation speed F from the storage unit (ST32).

  Next, the control means 60 refers to the expansion valve / electromagnetic valve control table 200, and opens / closes the electromagnetic valve 21 according to the acquired condensing pressure HP and the read compressor rotational speed F, and a pulse applied to the second expansion valve 22. Numbers are extracted (ST32).

  Next, the control means 60 adds the extracted number of pulses to the second expansion valve 22 to adjust the opening degree of the second expansion valve 22 (ST34), and at the same time opens and closes the extracted electromagnetic valve 21 according to the opening and closing of the electromagnetic valve 21. Is opened or closed (ST35). And the control means 60 complete | finishes the injection control during a driving | operation.

  As described above, the heat pump cycle device of the present invention closes the opening / closing means depending on the condensing pressure and the rotational speed of the compressor during startup in the heating cycle or during heating operation. Thereby, an extremely small amount of liquid refrigerant can be caused to flow through the injection pipe by the second expansion valve and the flow rate regulating means, and vibrations caused by pressure fluctuations inside the injection pipe can be suppressed. In addition, since the amount of liquid refrigerant flowing through the injection pipe can be made extremely small by the second expansion valve and the flow rate restricting means, a very small amount of liquid injection can be stably performed, and the selection range of the second expansion valve can be widened to increase design flexibility. Will improve.

DESCRIPTION OF SYMBOLS 1 Compressor 1a Intermediate pressure part 2 Four-way valve 3 Water refrigerant heat exchanger 4 1st expansion valve 5 Heat source side heat exchanger 6 Accumulator 10 Refrigerant circuit 14 Injection piping 15 Bypass pipe 21 Electromagnetic valve 22 2nd expansion valve 23 Capillary tube 30 Circulation pump 40 Indoor unit 50 Pressure sensor 51 Discharge refrigerant temperature sensor 52 Compressor temperature sensor 53 Refrigerant temperature sensor 54 Heat exchange temperature sensor 55 Outside air temperature sensor 56 Return temperature sensor 57 Outward temperature sensor 60 Control means 70 Refrigerant flow 80 Water flow 90 Injection Refrigerant flow in piping 100 Heat pump cycle device 200 Expansion valve / solenoid valve control table HP Condensation pressure F Compressor rotation speed

Claims (3)

The compressor, the use side heat exchanger, the first expansion valve, and the heat source side heat exchanger are sequentially connected by a refrigerant pipe, and one end is connected between the water refrigerant heat exchanger and the first expansion valve in the refrigerant pipe. A refrigerant circuit having an injection pipe in which the other end is connected to the intermediate pressure portion of the compressor and the flow rate regulating means and the second expansion valve are incorporated in series;
Condensation pressure detection means;
A heat pump cycle device comprising a control means for controlling the rotational speed of the compressor,
The injection pipe is provided with a bypass pipe provided with an opening / closing means that bypasses the flow rate regulating means,
The control means includes
When starting the refrigerant circuit as a heating cycle, close the opening and closing means until the temperature of the compressor reaches a predetermined temperature,
When the refrigerant circuit is operating as a heating cycle after the temperature of the compressor reaches a predetermined temperature, depending on the condensation pressure detected by the condensation pressure detection means and the rotation speed of the compressor, Open / close control of the opening / closing means;
The heat pump cycle apparatus characterized by the above-mentioned. In the heat pump cycle device according to claim 1,
The heat pump cycle device, wherein the flow rate regulating means is a capillary tube. In the heat pump cycle device according to claim 1 or 2,
The heat pump cycle device, wherein the compressor is a rotary compressor.

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