Refrigeration cycle device

Abstract

To provide a refrigeration cycle device that prevents or suppresses a flow sound in decompression means of a start bypass circuit.SOLUTION: A refrigeration cycle device R of the present invention comprises a compressor 4 which has a chamber 4c, and a bypass circuit b1 which couples discharge piping 5 and suction piping 3 of the compressor 4, wherein the bypass circuit b1 is opened before the compressor 4 is started to let refrigerant gas in the chamber 4c bypass the compressor 4 to its low pressure side, and the bypass circuit b1 has a decompression mechanism 8 in which a refrigerant flows in the gravitational direction.SELECTED DRAWING: Figure 4C

Description

[Technical field]

[0001] The present invention relates to a refrigeration cycle device. [Background technology]

[0002] When shutting down, scroll chillers usually perform a pump-down shutdown, in which the liquid solenoid valve is closed and the refrigerant in the low-pressure cycle is recovered by the compressor. After the pump-down shutdown, a bypass is performed using a startup bypass circuit installed between the high-pressure and low-pressure piping to reduce the pressure difference before and after the compressor is restarted.

[0003] Normally, the start-up bypass circuit is equipped with a solenoid valve, and when the solenoid valve of the start-up bypass circuit opens, flow noise occurs. Therefore, a pressure reducing mechanism is provided to suppress the flow noise. However, flow noise occurs under certain conditions, such as when there is a large difference between high and low pressures.

[0004] Therefore, in Patent Document 1, the discharge side and the suction side of the compressor (1) are connected by a bypass passage (6) equipped with an on-off valve (7) and a pressure reducing means (8). A pressure sensor (9) is disposed between the on-off valve (7) and the pressure reducing means (8). With this configuration, when the on-off valve (7) is closed, the pressure reducing means (8) acts to cause the pressure sensor (9) to detect a low pressure.

[0005] On the other hand, when the on-off valve (7) is open, the high pressure is detected by the pressure sensor (9) due to the operation of the compressor (1). As a result, with a simple and inexpensive configuration consisting of the on-off valve (7), the pressure reducing means (8), and the pressure sensor (9), it is possible to realize "constant evaporation pressure control" based on the low pressure during cooling operation and "constant condensation pressure control" based on the high pressure during heating operation. In addition, it is possible to reduce the cost of improving the cooling and heating performance of the air conditioner. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-350004 A (Fig. 1, Fig. 2, paragraph 0034, etc.) [Patent Document 2] Japanese Patent Application Publication No. 8-313067 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, the start-up bypass circuit is provided with a pressure reducing means (8) to suppress flow noise, but when the difference between high and low pressures is large or the ambient temperature is low, the refrigerant may liquefy and generate another type of flow noise. When the difference between high and low pressures is large or the ambient temperature is low, the cause of the flow noise is the passage of a gas-liquid two-phase flow through the pressure reducing means (8).

[0008] The present invention has been made in view of the above circumstances, and has an object to provide a refrigeration cycle apparatus in which flow noise is prevented or suppressed in the pressure reducing means of the starter bypass circuit. [Means for solving the problem]

[0009] In order to solve the above problems, the refrigeration cycle device of the present invention comprises a compressor having a chamber and a bypass circuit connecting a discharge pipe and a suction pipe of the compressor, the bypass circuit being opened before the compressor is started and bypassing the refrigerant gas in the chamber to a low pressure side of the compressor, and the bypass circuit having a pressure reducing mechanism in which the refrigerant flows in the direction of gravity. Effect of the Invention

[0010] According to the present invention, it is possible to provide a refrigeration cycle apparatus in which flow noise is prevented or suppressed in the pressure reducing means of the starter bypass circuit. [Brief description of the drawings]

[0011] [Figure 1] 1 is a circuit diagram of a refrigeration cycle device according to an embodiment of the present invention. [Diagram 2] Enlarged view of part I in Figure 1. [Figure 3A]FIG. 13 is a schematic diagram of a state of a pressure reducing mechanism in a start-up bypass circuit before start-up bypass in a comparative example. [Figure 3B] FIG. 13 is a schematic diagram showing a state of a pressure reducing mechanism in the start-up bypass circuit after start-up bypass in the comparative example. [Figure 3C] Enlarged view of part II in Figure 3B. [Figure 4A] FIG. 4 is a schematic diagram of a start-up bypass circuit including a pressure reducing mechanism according to the embodiment in a pre-start state; [Figure 4B] FIG. 4 is a schematic diagram of a start-up bypass circuit including a pressure reducing mechanism according to the embodiment in a pre-start state; [Figure 4C] FIG. 4 is a schematic diagram of a state after startup of the start-up bypass circuit including the pressure reducing mechanism of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 shows a circuit diagram of a refrigeration cycle apparatus R according to an embodiment of the present invention. The refrigeration cycle apparatus R of the embodiment includes a refrigerator r1 disposed outdoors and an evaporation unit r2 disposed indoors. The evaporation unit r2 cools the refrigeration cases, the inside of the refrigerator, the freezer cases, the inside of the freezers, etc., located indoors.

[0013] <Main refrigerant circuit of refrigeration cycle unit R> The configuration of the main refrigerant circuit of the refrigeration cycle device R shown in FIG. 1 will be described. The flow of the refrigerant will be described below in order from the suction inlet r1a of the refrigerator r1. First, the refrigerant gasified in the evaporator 15 of the indoor evaporation unit r2 passes through the intake gas piping 1 and flows into the accumulator 2 of the gas-liquid separator from the intake inlet r1a of the outdoor refrigerator r1. The accumulator 2 controls the amount of liquid refrigerant flowing into the compressor 4 to a certain value or less by gas-liquid separation of the refrigerant. This is because the compressor 4 becomes high pressure due to the inflow of incompressible liquid refrigerant, which may cause damage.

[0014] The gas refrigerant flowing out from the accumulator 2 passes through the compressor suction gas piping 3 and flows into the suction port 4i of the compressor 4. The gas refrigerant, whose pressure and temperature have been increased by the compression process of the compressor 4, is discharged from the discharge port 4o of the compressor 4. The gas refrigerant flowing out from the compressor 2 passes through the discharge gas piping 5 and enters the condenser 6, where it is condensed and becomes a liquid. Here, in order to reduce the load at the time of startup of the compressor 4, a startup bypass circuit b1 is provided between the discharge gas piping 5 and the compressor suction gas piping 3 (or suction gas piping 1). The startup bypass circuit b1 has an opening / closing mechanism 7 and a pressure reducing mechanism 8.

[0015] The refrigerant condensed in the condenser 6 flows to the receiver 9. The receiver 9 adjusts the excess of refrigerant in the entire cycle. For example, if there is too much refrigerant, liquid refrigerant may accumulate inside the condenser 6, which may lead to a decrease in the performance of the condenser 6. Therefore, by providing the receiver 9, the receiver 9 can hold the excess liquid refrigerant, thereby preventing a decrease in the performance of the condenser 6. The refrigerant that leaves the receiver 9 is branched into an injection circuit 10 and a liquid refrigerant pipe 11. The refrigerant flowing through the liquid refrigerant pipe 11 reaches an expansion valve 14 in the outdoor evaporation unit r2.

[0016] The refrigerant decompressed by the expansion valve 14 evaporates in the evaporator 15, thereby cooling the object to be cooled and gasifying it. The refrigerant gasified by the evaporator 15 passes through the intake gas piping 1 and reaches the intake inlet r1a of the refrigerator r1 again. The compressor 4 has an intake port 4i, a discharge port 4o, an injection port 4j, and a compression chamber 4r. The injection port 4j is structured to be connected to a portion of the compression process in the compression chamber 4r. Unlike a general air conditioner, the refrigerator r1 needs to keep the evaporation temperature low in order to perform refrigeration and freezing even when the outside air temperature is high.

[0017] For this reason, the difference between the suction pressure and discharge pressure of the refrigerant compressor 4 is likely to become large. When the difference between the suction pressure and discharge pressure is large, the temperature of the gas refrigerant is likely to rise during the compression process, and depending on the conditions, it is possible that the temperature may exceed 100°C, for example. The compressor 4 has a set upper limit for the temperature of the discharge gas. If this upper limit is exceeded, in the worst case scenario, the compressor 4 may break down.

[0018] Therefore, in order to lower the discharge temperature, the refrigeration cycle device R is provided with an injection circuit 10. The injection circuit 10 injects a refrigerant with low enthalpy into an injection port 4j connected to a compression chamber 4r in the compression process. The injection circuit 10 is composed of an opening / closing mechanism 12 and an expansion valve 13.

[0019] When the refrigerator r1, which is a scroll refrigerator, is stopped, the opening and closing mechanism 7 of the liquid solenoid valve is closed and the refrigerant in the compressor suction gas piping 3 in the low-pressure side cycle is recovered by the compressor 4, thereby performing a pump-down stop.

[0020] FIG. 2 shows an enlarged view of part I in FIG. After the pump-down is stopped and before the compressor 4 is restarted, a bypass is provided via a startup bypass circuit b1 provided between the discharge gas pipe 5, which is a high-pressure pipe, and the compressor suction gas pipe 3, which is a low-pressure pipe, in order to reduce the pressure difference between the front and rear of the compressor 4. The starter bypass circuit b1 includes a bypass pipe 17, an opening and closing mechanism 7, and a pressure reducing mechanism 8. The pressure reducing mechanism 8 is a throttle pipe (a pipe with a reduced inner diameter). By using the pressure reducing mechanism 8 as a throttle pipe, the gas phase refrigerant r1 can be reduced in pressure with a simple configuration.

[0021] <Pressure reducing mechanism 108 of start-up bypass circuit b101 of comparative example> 3A is a schematic diagram showing the state of the pressure reducing mechanism 108 in the start-up bypass circuit b101 before start-up bypass in a comparative example. Note that the direction of arrow G in FIG. 3A indicates the direction in which gravity is applied. The start-up bypass piping b101 including the pressure reducing mechanism 108 downstream of the opening and closing mechanism (not shown) of the comparative example is formed in a substantially U-shape as shown in Fig. 3A. The pressure reducing mechanism 108 is formed downstream of the substantially U-shaped start-up bypass piping b101.

[0022] Liquid phase refrigerant r0 is stored at a bottom b101t of the substantially U-shaped start-up bypass pipe b101 under the force of gravity G. On the other hand, gas phase refrigerant r1 is lighter than liquid phase refrigerant r0 and is therefore present above the liquid phase refrigerant r0.

[0023] Fig. 3B is a schematic diagram showing the state of the pressure reducing mechanism 108 of the start-up bypass circuit b101 after start-up bypass in the comparative example. Fig. 3C is an enlarged view of part II in Fig. 3B. After the start-up bypass, in the start-up bypass circuit b101 of the comparative example, the gas-phase refrigerant r1 flows as indicated by the arrow α101. Then, the liquid-phase refrigerant r0 at the bottom b101t flows as it is pushed by the gas-phase refrigerant r1, and in the pressure reduction mechanism 108, the gas-phase refrigerant r1 and the liquid-phase refrigerant r0 flow upward against gravity G and become mixed. At this time, the mixed state of the gas-phase refrigerant r1 and the liquid-phase refrigerant r0 in the pressure reduction mechanism 108 generates abnormal noise.

[0024] That is, when the flow of refrigerant r is upward against gravity G in the decompression mechanism 108, the liquid-phase refrigerant r0 in front of the decompression mechanism 108 rises by being sucked up by the gas-phase refrigerant r1, so that the gas-phase refrigerant r1 and the liquid-phase refrigerant r0 pass alternately inside the decompression mechanism 108. In addition to the difference in flow speed between the gas-phase refrigerant r1 and the liquid-phase refrigerant r0, their compressibility is also different, so that the refrigerant r vibrates at the outlet of the decompression mechanism 108 and generates a flow sound (abnormal sound).

[0025] <Pressure reduction mechanism 8 of start-up bypass circuit b1 (see FIG. 2) according to the embodiment> 4A and 4B are schematic diagrams showing a state before start-up of the start-up bypass circuit b1 including the pressure reducing mechanism 8 of the embodiment.

[0026] Fig. 4C is a schematic diagram showing a state after startup of the start-up bypass circuit b1 including the pressure reducing mechanism 8 of the embodiment. Note that in Figs. 4A to 4C, the direction of the arrow α11 indicates the direction in which the refrigerant r flows. 4A and 4B, the bypass piping 17 including the pressure reducing mechanism 8 of the embodiment has a substantially U-shape. The pressure reducing mechanism 8 is formed with a reduced diameter on the upstream side of the substantially U-shaped bypass piping 17 (the side where the bypass piping 17 extends downward).

[0027] As shown in FIG. 2, the bypass piping 17 including the pressure reducing mechanism 8 is provided so that the gradient of the path from the outlet o of the opening and closing mechanism 7 to the outlet 8o of the pressure reducing mechanism 8 is negative. The pressure reduction mechanism 8 is a downward piping or a piping in a region with a negative gradient. Alternatively, the bypass piping 17 between the pressure reduction mechanism 8 and the opening and closing mechanism 7 is formed at a position higher than the pressure reduction mechanism 8. In other words, the pressure reduction mechanism 8 is disposed at a position lower than the opening and closing mechanism 7. Alternatively, the bypass piping 17 is configured such that liquid refrigerant does not accumulate between the opening and closing mechanism 7 and the pressure reduction mechanism 8. This makes it possible to suppress abnormal noise in the pressure reduction mechanism 8 as described below.

[0028] Before activation, the pressure reducing mechanism 8 of the activation bypass circuit b1 is in the state shown in FIGS. 4A and 4B. As shown in Fig. 4A, before startup, liquid-phase refrigerant r0 is stored in the bottom b1t of the startup bypass circuit b1, while the other parts are filled with gas-phase refrigerant r1 or air. Alternatively, as shown in FIG. 4B, before startup, liquid-phase refrigerant r0 remains in the pressure reducing mechanism 8, which is reduced in diameter in the startup bypass circuit b1, due to surface tension.

[0029] Thereafter, when the system is started, the liquid-phase refrigerant r0 at the bottom b1t of the start-up bypass circuit b1 (see FIG. 4A) or the liquid-phase refrigerant r0 at the pressure reduction mechanism 8 of the start-up bypass circuit b1 (see FIG. 4B) is caused to flow upstream as shown in FIG. 4C. At this time, the liquid-phase refrigerant r0 mixes with the gas-phase refrigerant r1 and flows downstream. At this time, the pressure reduction mechanism 8 is formed so that the liquid-phase refrigerant r0 flows downward due to gravity G, so the phenomenon of the gas-phase refrigerant r1 and the liquid-phase refrigerant r0 flowing into the pressure reduction mechanism 8 does not occur. Therefore, the generation of abnormal noise in the pressure reduction mechanism 8 can be suppressed.

[0030] 4A, when the flow of refrigerant r is downward in the pressure reduction mechanism 8, even if liquid-phase refrigerant r0 is present in the bypass piping 17 when the opening and closing mechanism 7 is "closed," the refrigerant accumulates downstream of the pressure reduction mechanism 8. In that case, when the opening and closing mechanism 7 is opened and gas-phase refrigerant r1 flows, the refrigerant r does not pass through the pressure reduction mechanism 8 as a two-phase flow, and therefore no flow noise is generated.

[0031] 4B, even if a liquid pool of refrigerant r is formed in the pressure reducing mechanism 8 due to capillary action or the like, when the opening and closing mechanism 7 is "opened," only liquid phase refrigerant r0 flows continuously due to being pushed by gas phase refrigerant r1, and then only gas phase refrigerant r1 flows. Therefore, the refrigerant does not pass through the pressure reducing mechanism 8 as a two-phase flow, and no flow noise is generated. Flow noise can be prevented or suppressed.

[0032] According to the above configuration, when the opening and closing mechanism 7 is closed, the bypass piping 17 between the opening and closing mechanism 7 and the pressure reduction mechanism 8 is open only in the direction of gravity, so that no liquid phase refrigerant r exists between the opening and closing mechanism 7 and the pressure reduction mechanism 8. Therefore, even when the high-low pressure difference is large or the ambient temperature is low, only the gas phase refrigerant flows through the pressure reduction mechanism 8 when bypassing is performed using the start-up bypass circuit b1, and no flow noise is generated. Therefore, it is possible to realize a refrigeration cycle apparatus R that does not produce flow noise in the pressure reducing mechanism 8 of the starter bypass circuit b1.

[0033] <<Other embodiments>> 1. The present invention is not limited to the configuration of the above-described embodiment, and various modifications and specific forms are possible within the scope of the appended claims. [Explanation of symbols]

[0034] 3 Compressor suction gas piping (suction piping) 4. Compressor 4r compression chamber 5 Discharge gas piping (discharge piping) 7 Opening and closing mechanism 7o Exit of opening and closing mechanism 8 Pressure reduction mechanism 8o Pressure reducing mechanism outlet 17 Bypass piping (startup bypass piping) b1 Startup bypass circuit (bypass circuit) R Refrigeration cycle device

Claims

1. A compressor having a compression chamber; a bypass circuit connecting a discharge pipe and a suction pipe of the compressor; The bypass circuit includes: This valve is opened before the compressor is started, and allows the refrigerant gas in the compression chamber to be bypassed to the low pressure side of the compressor. The bypass circuit includes: It has a pressure reducing mechanism where the refrigerant flows in the direction of gravity. A refrigeration cycle device characterized by:

2. A compressor; a bypass circuit connecting a discharge pipe and a suction pipe of the compressor; an opening / closing mechanism and a pressure reducing mechanism provided in this order in a path from the discharge pipe to the suction pipe in the bypass circuit, The gradient of the path from the outlet of the opening / closing mechanism to the outlet of the pressure reducing mechanism is negative. A refrigeration cycle device characterized by:

3. The refrigeration cycle apparatus according to claim 1 or 2, When the start-up bypass piping of the bypass circuit is configured in a substantially U-shape, the pressure reducing mechanism is a descending pipe or a region with a negative gradient. A refrigeration cycle device characterized by:

4. The refrigeration cycle apparatus according to claim 1 or 2, The pressure reducing mechanism is a throttle tube. A refrigeration cycle device characterized by:

5. The refrigeration cycle apparatus according to claim 1 or 2, The bypass circuit includes: An opening / closing mechanism is provided upstream of the pressure reducing mechanism, The pipeline between the pressure reducing mechanism and the opening and closing mechanism is formed at a position higher than the pressure reducing mechanism. A refrigeration cycle device characterized by:

6. The refrigeration cycle apparatus according to claim 1 or 2, The bypass circuit includes: An opening / closing mechanism is provided upstream of the pressure reducing mechanism, The structure is such that liquid refrigerant does not accumulate between the opening and closing mechanism and the pressure reducing mechanism. A refrigeration cycle device characterized by:

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