JP6942265B2 - Heat source equipment and refrigeration cycle equipment - Google Patents

Description

The present invention relates to a heat source device and a refrigeration cycle device having a screw compressor.

Conventionally, a heat source device having a screw compressor has been known (see, for example, Patent Document 1). In Patent Document 1, the opening degree of the electronic expansion valve is controlled when the heat source device is started.

JP-A-2007-85615

In Patent Document 1, the opening degree of the electronic expansion valve is controlled to reach stable operation from the start of the heat source device. In Patent Document 1, since the heat source device is stabilized while circulating a large amount of refrigerant, it may take a long time from the start of the heat source device to the stabilization of the heat source device.

The present invention has been made in view of the above problems, and an object of the present invention is to obtain a heat source device capable of shortening the time from starting the heat source device to stabilizing the heat source device. ..

The heat source device according to the present invention has a screw rotor, a casing that accommodates the screw rotor and forms a compression chamber together with the screw rotor, and a casing that is formed in the casing and is lower than the first pressure portion and the first pressure portion of the compression chamber. A screw compressor provided with a bypass section for connecting a second pressure section of pressure and an adjusting section provided in the bypass section for adjusting the compression ratio of the compression chamber, and the temperature of the refrigerant sucked by the screw compressor. Alternatively, the suction sensor that detects the degree of overheating and the control that communicates the bypass part before the set time elapses after the screw compressor is started and when the detection result of the suction sensor is higher than the first set value. e Bei and a control unit for executing the bypass portion, by adjusting part is slid along the rotation axis direction of the screw rotor, in which the opening area is adjusted.

In the heat source device of the present invention, before the set time elapses after the screw compressor is started, and when the detection result of the suction sensor is higher than the first set value, the medium pressure portion and the low pressure portion of the compression chamber are formed. By connecting and reducing the compression ratio, the operation of the heat source device is stabilized. Therefore, according to the heat source device of the present invention, the time from the start of the heat source device to the stabilization of the heat source device can be shortened.

It is a figure which shows an example of the refrigeration cycle apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the screw compressor described in FIG. It is a figure which shows an example of the suction process of the compression chamber of the screw compressor described in FIG. It is a figure which shows an example of the compression process of the compression chamber of the screw compressor described in FIG. It is a figure which shows an example of the discharge process of the compression chamber of the screw compressor described in FIG. It is a figure which shows an example when the slide valve of the screw compressor described in FIG. 2 is in a 1st position. It is a figure which shows an example when the slide valve described in FIG. 6 is in a 2nd position. It is a figure which shows an example when the slide valve described in FIG. 6 is in a 3rd position. It is a figure which shows the relationship between a slide valve and a bypass opening when the slide valve shown in FIG. 6 is in a 1st position. It is a figure which shows the relationship between a slide valve and a bypass opening when the slide valve shown in FIG. 6 is in a 2nd position. It is a figure which shows the relationship between a slide valve and a bypass opening when the slide valve shown in FIG. 6 is in a third position. It is a figure explaining the operation of the refrigeration cycle apparatus when the slide valve shown in FIG. 6 is in a 1st position. It is a figure explaining the operation of the refrigeration cycle apparatus when the slide valve shown in FIG. 6 is in a second position. It is a figure explaining the operation of the refrigeration cycle apparatus when the slide valve shown in FIG. 6 is in a third position. It is a figure which shows an example of the control at the time of starting of the refrigeration cycle apparatus described in FIG. It is a figure which shows the modification 1 of Embodiment 1. It is a figure which shows an example of the control at the time of starting of the refrigerating cycle apparatus of the modification 1 of Embodiment 1. It is a figure which shows an example of the screw compressor which concerns on Embodiment 2 of this invention. It is a figure which shows an example of the control at the time of starting of the refrigeration cycle apparatus of Embodiment 2. It is a figure which shows an example of the screw compressor which concerns on Embodiment 3 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be omitted or simplified as appropriate. In addition, the shape, size, arrangement, etc. of the configurations shown in each figure can be appropriately changed within the scope of the present invention.

Embodiment 1.
[Refrigeration cycle equipment]
FIG. 1 is a diagram showing an example of a refrigeration cycle device according to the first embodiment of the present invention. The refrigeration cycle device 100 of this embodiment is applied to a refrigeration device that cools a cooling space such as a warehouse. The refrigeration cycle device 100 can be applied to an air conditioner for air-conditioning a building or the like. The refrigeration cycle device 100 has a heat source device 200 and a load device 400. The heat source device 200 is provided outside the cooling space and supplies heat to the load device 400. The heat source device 200 is provided outdoors, for example, but may be provided in a machine room or the like. The load device 400 is provided inside the cooling space and cools the cooling space. The load device 400 includes an expansion valve 105, a load side heat exchanger 106, and a load side blower (not shown). The expansion valve 105 expands the refrigerant. The expansion valve 105 is, for example, an electronic expansion valve whose opening degree can be adjusted, but may be a capillary tube whose opening degree cannot be adjusted. The expansion valve 105 may be provided outside the load device 400. The load side heat exchanger 106 exchanges heat with the refrigerant. The load side heat exchanger 106 is a fin tube type heat exchanger formed of fins and tubes. The load-side heat exchanger 106 may be a plate-type heat exchanger or the like that exchanges heat between the refrigerant and a heat medium such as water. The load-side heat exchanger 106 of this embodiment functions as an evaporator that evaporates the refrigerant. The load-side blower (not shown) blows air to the load-side heat exchanger 106. When the load-side blower (not shown) blows air, the air that has exchanged heat with the load-side heat exchanger 106 is blown out into the cooling space.

The heat source device 200 includes a screw compressor 102 and a heat source side heat exchanger 104. The screw compressor 102 compresses the refrigerant. The screw compressor 102 of the example of this embodiment is a two-stage single screw compressor, and has a screw rotor 3a, a high-pressure screw rotor 3b, and a motor 103. The motor 103 operates by supplying electric power from a power supply source (not shown) to the motor 103 via the inverter 101. When the motor 103 operates, the screw rotor 3a and the high-pressure screw rotor 3b connected to the motor 103 rotate, and the refrigerant is compressed. The heat source side heat exchanger 104 is a fin tube type heat exchanger formed of fins and tubes. The heat source side heat exchanger 104 may be a plate-type heat exchanger or the like that exchanges heat between the refrigerant and a heat medium such as water. The heat source side heat exchanger 104 of this embodiment functions as a condenser for condensing the refrigerant. The heat source side blower (not shown) blows air to the heat source side heat exchanger 104. When the heat source side blower (not shown) blows air, heat exchange in the heat source side heat exchanger 104 is promoted. Further, the heat source device 200 includes a control device 110 and sensors. The control device 110 may be provided outside the heat source device 200, and may be provided inside, for example, the load device 400. The control device 110 is formed of a microcomputer or the like including a CPU, a RAM for storing various data, and a ROM (none of which is shown) for storing a program or the like for performing operation control. The control device 110 controls the entire refrigeration cycle device 100. The control device 110 controls, for example, the expansion valve 105, the screw compressor 102, and the like. The sensors included in the heat source device 200 include a suction temperature sensor that detects the temperature of the refrigerant sucked into the screw compressor 102, a suction pressure sensor that detects the pressure of the refrigerant sucked into the screw compressor 102, and the screw compressor 102. It has a discharge temperature sensor that detects the temperature of the discharged refrigerant, a discharge pressure sensor that detects the pressure of the refrigerant discharged by the screw compressor 102, and the like. The suction temperature sensor or suction pressure sensor corresponds to the "suction sensor" of this embodiment. The degree of superheat of the refrigerant sucked by the screw compressor 102 is calculated from, for example, the temperature detected by the suction temperature sensor and the saturated gas temperature calculated from the pressure detected by the suction pressure sensor.

[Refrigerant circuit]
The refrigerant circuit 109 is formed by connecting the heat source device 200 and the load device 400 with a refrigerant pipe. The refrigerant circuit 109 is formed by connecting the screw compressor 102, the heat source side heat exchanger 104, the expansion valve 105, and the load side heat exchanger 106 by a refrigerant pipe, and circulates the refrigerant. The high-temperature and high-pressure refrigerant compressed by the screw compressor 102 dissipates heat while being condensed by the heat source side heat exchanger 104. The refrigerant condensed in the heat source side heat exchanger 104 expands in the expansion valve 105. The refrigerant expanded by the expansion valve 105 absorbs heat from the air while evaporating by the load side heat exchanger 106 to cool the air. The refrigerant evaporated in the load side heat exchanger 106 is sucked into the screw compressor 102 and compressed again.

[Screw compressor]
FIG. 2 is a diagram showing an example of the screw compressor described in FIG. As shown in FIG. 2, a motor 103, a screw rotor 3a, a high-pressure screw rotor 3b, a screw shaft 4, a gate rotor 6a, and a high-pressure gate rotor 6b are provided inside a cylindrical casing 10 forming the screw compressor 102. There is. Further, inside the casing 1, a partition wall (not shown) that separates the low pressure side and the high pressure side is provided. The refrigerant compressed by the low-pressure compression unit having the screw rotor 3a is discharged to the intermediate chamber 11. The refrigerant in the intermediate chamber 11 is compressed by a high-pressure compression unit having a high-pressure screw rotor 3b, and is discharged from a discharge port (not shown) provided in the casing 10. The motor 103 has a stator 2a fixed inside the casing 1 and a motor rotor 2b provided inside the stator 2a. The screw rotor 3a, the high-pressure screw rotor 3b, and the motor rotor 2b are provided on the same axis. The screw rotor 3a, the high-pressure screw rotor 3b, and the motor rotor 2b are connected by a screw shaft 4. A plurality of spiral compression grooves forming the compression chamber 5a are formed on the outer peripheral surface of the screw rotor 3a, and a plurality of spiral compression grooves forming the high pressure compression chamber 5b are formed on the outer peripheral surface of the high pressure screw rotor 3b. A compression groove is formed. The gate rotor 6a has a plurality of teeth that are meshed with compression grooves formed on the outer peripheral surface of the screw rotor 3a. The high pressure gate rotor 6b has a plurality of teeth that are meshed with compression grooves formed on the outer peripheral surface of the high pressure screw rotor 3b. The compression chamber 5a is formed of an inner peripheral surface of the casing 10, a screw rotor 3a, a gate rotor 6a, and the like. The high-pressure compression chamber 5b is formed of an inner peripheral surface of the casing 10, a high-pressure screw rotor 3b, a high-pressure gate rotor 6b, and the like. The screw rotor 3a and the high-pressure screw rotor 3b are rotationally driven by the rotation of the motor rotor 2b. As the screw rotor 3a rotates, the teeth of the gate rotor 6a move relatively inside the compression groove of the screw rotor 3a. As the high-pressure screw rotor 3b rotates, the teeth of the high-pressure gate rotor 6b move relatively inside the compression groove of the high-pressure screw rotor 3b. By the above operation, each of the compression chamber 5a and the high-pressure compression chamber 5b repeats this cycle with the suction stroke, the compression stroke, and the discharge stroke as one cycle.

[Operation of screw compressor]
FIG. 3 is a diagram showing an example of a suction step of the compression chamber of the screw compressor shown in FIG. FIG. 4 is a diagram showing an example of a compression process of the compression chamber of the screw compressor shown in FIG. FIG. 5 is a diagram showing an example of a discharge process of the compression chamber of the screw compressor shown in FIG. In FIGS. 3 to 5, the compression process will be described by focusing on the compression chamber 5a indicated by the hatching of dots. FIG. 3 shows the state of the compression chamber 5a in the suction stroke. When the screw rotor 3a rotates in the direction of the solid arrow, the volume of the compression chamber 5a is reduced as shown in FIG. Further, when the screw rotor 3a rotates, the compression chamber 5a communicates with the discharge portion 12 as shown in FIG. The high-pressure refrigerant compressed in the compression chamber 5a is discharged from the discharge unit 12. The refrigerant discharged from the discharge unit 12 is sucked into the high-pressure compression chamber 5b and further compressed. Since the high-pressure compression chamber 5b compresses the refrigerant in the same manner as the compression chamber 5a, the description thereof will be omitted.

FIG. 6 is a diagram showing an example when the slide valve of the screw compressor shown in FIG. 2 is in the first position. FIG. 7 is a diagram showing an example when the slide valve shown in FIG. 6 is in the second position. FIG. 8 is a diagram showing an example when the slide valve shown in FIG. 6 is in the third position. FIG. 9 is a diagram showing the relationship between the slide valve and the bypass opening when the slide valve shown in FIG. 6 is in the first position. FIG. 10 is a diagram showing the relationship between the slide valve and the bypass opening when the slide valve shown in FIG. 6 is in the second position. FIG. 11 is a diagram showing the relationship between the slide valve and the bypass opening when the slide valve shown in FIG. 6 is in the third position. FIG. 12 is a diagram illustrating the operation of the refrigeration cycle device when the slide valve shown in FIG. 6 is in the first position. FIG. 13 is a diagram illustrating the operation of the refrigeration cycle device when the slide valve shown in FIG. 6 is in the second position. FIG. 14 is a diagram illustrating the operation of the refrigeration cycle device when the slide valve shown in FIG. 6 is in the third position. As shown in FIGS. 6 to 8, the screw compressor 102 has a slide valve 7. The slide valve 7 operates during transient operation or the like. The slide valve 7 is slidably provided inside the casing 10. The slide valve 7 is connected to a drive device 9 such as a piston via a connecting rod 8. The drive device 9 uses, for example, a piston driven by gas pressure or flood control, but may be driven by a motor or the like. By driving the drive device 9, the slide valve 7 slides in the direction of the rotation axis of the screw rotor 3a. The slide valve 7 forms a part of the compression chamber 5a together with the inner peripheral surface of the casing 10. That is, as shown in FIGS. 9 to 11, a bypass opening 70 is formed in the casing 10. The bypass opening 70 is a hole formed in the casing 10 so as to connect the medium pressure portion that becomes the medium pressure of the compression chamber 5a and the low pressure portion that becomes the low pressure of the compression chamber 5a. The low-pressure portion communicates with the suction portion in which the compression chamber 5a sucks the refrigerant, and the medium-pressure portion and the low-pressure portion communicate with each other to reduce the suction volume. The opening area of the bypass opening 70 is adjusted by moving the slide valve 7 along the axial direction. By adjusting the opening area of the bypass opening 70, the suction volume at which the compression chamber 5a sucks the refrigerant is adjusted. In the slide valve 7 of this embodiment, two slide valves 7 slide and move at the same time, but the number of slide valves 7 may be one. The number of slide valves 7 may be three or more. The bypass opening 70 corresponds to the "bypass portion" of this embodiment, and the slide valve 7 corresponds to the "adjustment portion" of this embodiment. The bypass opening 70 may be formed so as to connect the first pressure portion and the second pressure portion having a pressure lower than that of the first pressure portion. The pressure ratio can be reduced by communicating the high pressure portion and the low pressure portion.

The slide valve 7 of this embodiment moves to three positions: a first position shown in FIG. 6, a second position shown in FIG. 7, and a third position shown in FIG. At the first position shown in FIG. 6, the slide valve 7 covers most of the bypass opening 70, ideally completely closing the bypass opening 70, as shown in FIG. By providing the slide valve 7 at the first position, the suction volume of the compression chamber 5a is maximized. When the suction volume of the compression chamber 5a is maximized, the compression ratio by the compression chamber 5a is maximized as shown in FIG.

At the second position shown in FIG. 7, the slide valve 7 opens most of the bypass opening 70 as shown in FIG. By providing the slide valve 7 at the second position, the suction volume of the compression chamber 5a becomes smaller than when the slide valve 7 is provided at the first position. As the suction volume of the compression chamber 5a becomes smaller, the compression ratio by the compression chamber 5a becomes smaller as shown in FIG.

At the third position shown in FIG. 8, the slide valve 7 opens a medium amount of the bypass opening 70 as shown in FIG. By providing the slide valve 7 in the second position, the suction volume of the compression chamber 5a becomes smaller than when the slide valve 7 is provided in the first position, and the slide valve 7 is in the third position. The suction volume of the compression chamber 5a is larger than that of the case where the compression chamber 5a is provided. That is, in the example of this embodiment, the slide valve 7 is provided at the second position, so that the suction volume of the compression chamber 5a becomes medium. When the suction volume of the compression chamber 5a is medium, the compression ratio by the compression chamber 5a is medium, as shown in FIG. The slide valve 7 is not limited to the one that moves to three positions, and may move to two positions. The slide valve 7 may move in four or more positions. That is, it suffices that the suction volume can be changed by moving the slide valve 7. The slide valve 7 is usually in the first position where the suction volume is maximized during steady operation.

FIG. 15 is a diagram showing an example of control at the time of starting the refrigeration cycle apparatus shown in FIG. That is, the refrigeration cycle device 100 of this embodiment executes the control of FIG. 15 until the set time elapses after the start-up, and shifts to the normal control after the set time elapses. When the refrigeration cycle device 100 is applied to the refrigeration device, the control of FIG. 15 is executed for about several tens of minutes, depending on the length of the pipe. This is because when the amount of the refrigerant sealed in the refrigeration cycle device 100 is large, it may take a long time for the state of the refrigerant in the refrigerant circuit to stabilize. For example, when the operation of the refrigeration cycle device 100 is stopped for a long time in a region where the temperature is high or when the temperature is high, it takes a long time for the state of the low-pressure refrigerant to stabilize. This is because the amount of the refrigerant sealed in the low-pressure pipe and heated increases. At startup, the refrigeration cycle device 100 of this embodiment controls the slide valve 7 by utilizing the suction SH, which is the degree of superheat of the refrigerant sucked by the screw compressor 102. The refrigeration cycle device 100 of the example of this embodiment has three threshold values, a threshold value A, a threshold value B, and a threshold value C. The threshold value A, the threshold value B, and the threshold value C are set in advance and are stored in the control device 110, for example. The relationship between the three thresholds is threshold A> threshold B> threshold C. By setting the threshold value A> the threshold value B> the threshold value C, hunting can be suppressed.

In step S1 of FIG. 15, it is compared whether or not the suction SH is higher than the threshold value A. If the suction SH is equal to or less than the threshold value A in step S1, the process proceeds to step S4. When the suction SH is higher than the threshold value A in step S1, it is determined that the operation is transient, and the process proceeds to step S2. In step S2, the slide valve 7 is in the second position shown in FIG. When the suction SH is higher than the threshold value A in step S3, the process returns to step S2. When the suction SH becomes equal to or less than the threshold value A in step S3, the process proceeds to step S4.

In step S4, it is compared whether or not the suction SH is higher than the threshold value B. If the suction SH is equal to or less than the threshold value B in step S4, the process proceeds to step S7. If the suction SH is higher than the threshold value B in step S4, the process proceeds to step S5. In step S5, the slide valve 7 is in the third position shown in FIG. In step S6, it is compared whether or not the suction SH is higher than the threshold value C. When the suction SH is higher than the threshold value C in step S6, the process returns to step S5. When the suction SH becomes equal to or less than the threshold value C in step S6, the process proceeds to step S7. In step S7, the slide valve 7 is in the first position shown in FIG. 9, and returns to step S1.

As described above, the refrigeration cycle device 100 of this embodiment adjusts the position of the slide valve 7 to reduce the compression volume of the screw compressor 102 when the intake gas temperature is high at the time of starting. When the intake gas temperature at startup is high, the temperature of the refrigerant discharged from the screw compressor 102 can be lowered by reducing the compression volume of the screw compressor 102. By lowering the temperature of the refrigerant discharged from the screw compressor 102, seizure of the screw rotor 3a and the high-pressure screw rotor 3b can be suppressed. Further, according to this embodiment, the cooling target can reach the target temperature in a short time after the heat source device 200 is started.

Further, in this embodiment, the slide valve 7 is located at the first position during steady operation, and the suction volume is smaller than the second position or the second position during transient operation. The slide valve is moved to a third position that is larger and has a smaller suction volume than the first position. By adjusting the suction volume stepwise, the cooling capacity can be stepwise improved, so that the pull-down operation time can be shortened.

For example, the screw compressor 102 of the example of this embodiment is a two-stage screw compressor, and when the intake gas temperature at startup is high, the position of the slide valve 7 is adjusted to adjust the compression volume of the compression chamber 5a. Make it smaller and do not change the compression volume of the high pressure compression chamber 5b. By reducing the compression volume of the compression chamber 5a without changing the compression volume of the high-pressure compression chamber 5b, the intermediate pressure, which is the pressure of the intermediate chamber 11 shown in FIG. 2, decreases as shown in FIG. That is, the compression ratio of the low-pressure compression section having the screw rotor 3a is low, and the compression ratio of the high-pressure compression section having the high-pressure screw rotor 3b is high. As the compression ratio of the low-pressure compression section decreases, the discharge temperature of the low-pressure compression section decreases. As a result, the intake gas temperature of the high-pressure compression section is lowered, and the discharge temperature of the high-pressure compression section is lowered. When the intermediate chamber 11 is configured to perform injection, if the decrease in the discharge temperature of the low-pressure compression unit is small, the liquid is stored in the intermediate chamber 11 so that the discharge temperature of the high-pressure compression unit falls within a preset setting range. It is good to perform injection. By injecting the liquid into the intermediate chamber 11, it is possible to suppress an increase in the suction superheat degree of the high-pressure compression unit and keep the discharge temperature of the high-pressure compression unit within the set range. The injection into the intermediate chamber 11 is, for example, a refrigerant used for supercooling in an economizer, oil separated and cooled by an oil separator, or the like, as long as it can lower the discharge temperature of the high-pressure compression unit. good.

As described above, the heat source device 200 of the example of this embodiment has a screw rotor 3a, a casing 10 that accommodates the screw rotor 3a and forms a compression chamber 5a together with the screw rotor 3a, and a first pressure of the compression chamber 5a. A screw compressor 102 having a bypass section for connecting the section and a second pressure section having a pressure lower than that of the first pressure section, and suction for detecting the temperature or degree of superheat of the refrigerant sucked by the screw compressor 102. The sensor and the control device 110 that executes control to communicate the bypass portion before the set time elapses after the screw compressor 102 is started and when the detection result of the suction sensor is higher than the first set value. It is equipped with. According to this embodiment, after starting the heat source device 200, the operation of the heat source device 200 is stabilized by communicating the bypass portion to reduce the compression ratio of the compression chamber 5a, so that the heat source device 200 is used. After startup, the time until the operation of the heat source device 200 stabilizes can be shortened. In the example of this embodiment, the compression ratio of the compression chamber 5a is reduced as compared with the case of normal control until the set time elapses after the heat source device 200 is started. For example, in the example of this embodiment, after the heat source device 200 is started, the slide valve 7 is moved so that the bypass opening 70 is the largest until the set time elapses, and the compression ratio of the compression chamber 5a is maximized. Make it smaller. Further, according to this embodiment, it is possible to ensure the stabilization of the operation of the heat source device 200 after the start of the heat source device 200. Further, according to this embodiment, the cooling target can reach the target temperature in a short time after the heat source device 200 is started.

For example, the control device 110 executes control to communicate the bypass unit before the first time t1 before the set time elapses, regardless of the detection result of the inhalation sensor. By unconditionally reducing the compression ratio when the heat source device 200 is started, the start of the heat source device 200 can be stabilized. The heat source device 200 of this embodiment includes a screw rotor 3a, a casing 10 that accommodates the screw rotor 3a and forms a compression chamber 5a together with the screw rotor 3a, a first pressure portion of the compression chamber 5a, and the first pressure portion. A screw compressor 102 having a bypass part for connecting a second pressure part having a pressure lower than that of the pressure part 1 and a screw compressor 102 before the first time t1 elapses after the screw compressor 102 is started. It may be provided with a control device 110 that executes control for communicating the bypass portion. By unconditionally reducing the compression ratio when the heat source device 200 is started, the start of the heat source device 200 can be stabilized.

Further, for example, the heat source device 200 is provided with a plurality of bypass portions. Further, for example, the heat source device 200 is provided with an even number of bypass portions. Further, for example, in the heat source device 200, a pair of bypass portions are provided at positions that are line-symmetrical with the screw rotor 3a interposed therebetween. By providing a plurality of bypass portions, the amount of adjustment of the compression ratio can be increased. Further, by providing a plurality of bypass portions, the amount of adjustment of the compression ratio can be finely adjusted, for example, in a plurality of steps. Further, by controlling the pair of bypass portions at the same time, the behavior of the compression chamber 5a is stabilized.

Further, for example, the heat source device 200 is provided in the bypass portion and further includes an adjusting portion for adjusting the compression ratio of the compression chamber 5a. By making the compression ratio of the compression chamber 5a adjustable, the start-up of the heat source device 200 can be further stabilized. Further, the cooling target can reach the target temperature in a short time after the heat source device 200 is started.

Further, for example, the control device 110 controls the adjusting unit so that the compression ratio is set to the first compression ratio when the detection result of the suction sensor is a second set value higher than the first set value. When the detection result of the suction sensor is higher than the first set value and lower than the second set value, the adjustment unit is controlled so that the compression ratio is a second compression ratio smaller than the first compression ratio. do. By adjusting the compression ratio according to the detection result of the suction sensor, the cooling target can reach the target temperature in a short time after the heat source device 200 is started.

Further, for example, the bypass portion has a bypass opening 70 formed in the casing 10 so as to connect the first pressure portion and the second pressure portion, and the adjusting portion covers the bypass opening 70. A first position that does not allow the first pressure portion and the second pressure portion to communicate with each other, and a second position that allows the first pressure portion and the second pressure portion to communicate with each other without covering at least a part of the bypass opening 70. And, it has a slide valve 7 that slides and moves. By using the slide valve 7 to adjust the compression ratio, it is possible to reduce the dead volume that becomes unnecessary when operating without lowering the compression ratio.

Further, for example, the screw compressor 102 is a two-stage screw having a partition wall that separates the low-pressure side accommodating the compression chamber 5a and the high-pressure side accommodating the high-pressure compression chamber 5b that compresses the refrigerant compressed in the compression chamber 5a. It is a compressor. When the screw compressor 102 is a two-stage screw compressor, it is possible to execute control for adjusting the compression ratio on the low pressure side and control for adjusting the discharge timing on the high pressure side. It can be stabilized. Further, the cooling target can reach the target temperature in a short time after the heat source device 200 is started.

Further, for example, the second pressure portion communicates with the suction portion in which the compression chamber 5a sucks the refrigerant. Since the structure that communicates the suction part and the part with a pressure higher than the suction part is a structure that adjusts the suction volume, the behavior of the compression process is stabilized as compared with the structure that communicates the compression chambers in the compression process. can do.

Further, for example, the refrigeration cycle device 100 includes a heat source device 200 and a load device 400 connected to the heat source device 200. The effect of the heat source device 200 of this embodiment becomes remarkable when it is applied to a cooling warehouse or the like in which the pipe length connected to the load device 400 is long. This is because when the amount of the refrigerant stored in the refrigeration cycle device 100 is large, it is difficult to stabilize the state of the refrigerant after the refrigeration cycle device 100 is started, and a long time is required. In addition, in an area where the temperature is high or an article in which the temperature is high, the temperature of the refrigerant stored in the refrigerant pipe becomes high when the refrigeration cycle device 100 is stopped, so that the effect of the heat source device 200 of this embodiment becomes more remarkable. ..

It should be noted that this embodiment is not limited to that described above.

For example, in the above, the two-stage single-screw compressor has been described, but this embodiment can be applied to a two-stage twin-screw compressor, a single-stage single-screw compressor, a single-stage twin-screw compressor, and the like. can. That is, this embodiment can be applied to those in which the compression ratio of the compression unit can be adjusted.

Further, for example, in the above, an example of executing the control of the slide valve 7 by using the suction SH at the time of starting has been described, but the slide valve 7 is controlled by using the suction gas temperature instead of the suction SH. May be done. Further, the slide valve 7 at the time of starting may be controlled by using the suction SH and the suction gas temperature.

[Modification 1]
Further, for example, FIG. 16 is a diagram showing a modification 1 of the first embodiment. FIG. 17 is a diagram showing an example of control at the time of starting the refrigeration cycle device of the first modification of the first embodiment. As shown in FIGS. 16 and 17, in the first modification, the slide valve 7 is controlled by utilizing the low pressure and the intake gas temperature at the time of starting. The refrigeration cycle device 100 of the example of this embodiment has three threshold values, a threshold value D, a threshold value E, and a threshold value F. The threshold value D, the threshold value E, and the threshold value F are set in advance and are stored in the control device 110, for example. The relationship between the three thresholds is threshold D> threshold E> threshold F. By setting the threshold value D> the threshold value E> the threshold value F, hunting can be suppressed.

As shown in FIG. 16, the threshold value D, the threshold value E, and the threshold value F are values determined by the intake gas temperature and the low pressure. When the suction SH is the same, the higher the low pressure, the higher the suction gas temperature.
Therefore, as the low pressure pressure increases, the discharge gas temperature also increases, and the risk of seizure of the screw rotor 3a and the high pressure screw rotor 3b increases. When the low pressure is high, it is necessary to lower the upper limit of the suction SH. Therefore, by controlling the slide valve 7 by utilizing the relationship between the intake gas temperature and the low pressure, the slide valve 7 is operated as the first position when the low pressure is low as compared with the first embodiment. The range that can be expanded is expanded. By expanding the range in which the slide valve 7 can be operated as the first position, the efficiency of the refrigeration cycle device 100 is improved, and the cooling target can be efficiently cooled.

Next, the operation of the first modification will be described. In step S21 of FIG. 17, it is compared whether or not the intake gas temperature is higher than the threshold value D. If the intake gas temperature is equal to or lower than the threshold value D in step S21, the process proceeds to step S24. When the intake gas temperature is higher than the threshold value D in step S21, it is determined that the operation is transient, and the process proceeds to step S22. In step S22, the slide valve 7 is in the second position shown in FIG. When the intake gas temperature is higher than the threshold value D in step S23, the process returns to step S22. When the intake gas temperature becomes equal to or lower than the threshold value D in step S23, the process proceeds to step S24.

In step S24, it is compared whether or not the intake gas temperature is higher than the threshold value E. If the intake gas temperature is equal to or lower than the threshold value E in step S24, the process proceeds to step S27. If the intake gas temperature is higher than the threshold value E in step S24, the process proceeds to step S25. In step S25, the slide valve 7 is in the third position shown in FIG. In step S26, it is compared whether or not the intake gas temperature is higher than the threshold value F. When the intake gas temperature is higher than the threshold value F in step S26, the process returns to step S25. When the intake gas temperature becomes equal to or lower than the threshold value F in step S26, the process proceeds to step S27. In step S27, the slide valve 7 is in the first position shown in FIG. 9, and returns to step S21.

[Modification 2]
Further, for example, in the refrigeration cycle device 100 of the second modification, the suction volume of the compression chamber 5a is reduced after the start-up and before the control of FIG. 15 is executed. That is, during the preparation time until the first time t1 after the refrigeration cycle device 100 is started, the suction volume of the compression chamber 5a is kept small regardless of the size of the suction SH. Then, the refrigeration cycle device 100 executes the control of FIG. 15 after the preparation time has elapsed and until the set time has elapsed. As in the second modification, the screw rotor 3a and the high-pressure screw rotor 3b are seized by unconditionally reducing the suction volume of the compression chamber 5a after the refrigeration cycle device 100 is started until the preparation time elapses. Etc. can be further reduced. The preparation time is shorter than the set time. For example, when the set time is several tens of minutes, the preparation time is shorter than several minutes.

Embodiment 2.
FIG. 18 is a diagram showing an example of a screw compressor according to the second embodiment of the present invention. FIG. 19 is a diagram showing an example of control at the time of starting the refrigeration cycle apparatus of the second embodiment. In FIG. 18, the same configurations as those in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted or simplified. The screw compressor 102 of the example of this embodiment includes a first drive device 90a, a first connecting rod 80a, a first slide valve 70a, a second driving device 90b, a second connecting rod 80b, and a second. It has a slide valve 70b and the like. That is, in the first embodiment, the two slide valves 7 slide and move at the same time, and in the second embodiment, the first slide valve 70a and the second slide valve 70b slide and move independently. It is something to do.

Next, the operation of the screw compressor 102 of the second embodiment will be described. In step S11 of FIG. 19, it is compared whether or not the suction SH is higher than the threshold value A. If the suction SH is equal to or less than the threshold value A in step S11, the process proceeds to step S14. When the suction SH is higher than the threshold value A in step S11, it is determined that the operation is transient, and the process proceeds to step S12. In step S12, the first slide valve 70a and the second slide valve 70b are in the second position shown in FIG. When the suction SH is higher than the threshold value A in step S13, the process returns to step S12. When the suction SH becomes equal to or less than the threshold value A in step S13, the process proceeds to step S14.

In step S14, it is compared whether or not the suction SH is higher than the threshold value B. If the suction SH is equal to or less than the threshold value B in step S14, the process proceeds to step S17. If the suction SH is higher than the threshold value B in step S14, the process proceeds to step S15. In step S15, one of the first slide valve 70a and the second slide valve 70b is in the first position shown in FIG. 9, and the other does not move from the second position shown in FIG. In step S16, it is compared whether or not the suction SH is higher than the threshold value C. When the suction SH is higher than the threshold value C in step S16, the process returns to step S15. When the suction SH becomes equal to or less than the threshold value C in step S16, the process proceeds to step S7. In step S7, the first slide valve 70a and the second slide valve 70b are in the first positions shown in FIG. 9, and the process returns to step S11.

As described above, according to the second embodiment, since each of the first slide valve 70a and the second slide valve 70b slides and moves, the first slide valve 70a and the second slide valve 70b The suction volume of the compression chamber 5a can be adjusted in three stages by making each of the above positions movable to the first position and the second position. That is, the first embodiment is a complicated mechanism capable of adjusting the position of each of the slide valves 7 in three stages, whereas the second embodiment is the first slide valve 70a and the second slide valve 70b. It can be a simple mechanism that adjusts the position of each in two stages.

It should be noted that this embodiment is not limited to that described above. For example, the suction volume of the compression chamber 5a can be finely controlled by configuring each of the first slide valve 70a and the second slide valve 70b of the second embodiment to slide and move in a plurality of stages. .. For example, each of the first slide valve 70a and the second slide valve 70b can be located at the first position shown in FIG. 9, the second position shown in FIG. 10, and the third position shown in FIG. If configured, the suction volume can be adjusted in five or more steps. That is, the combination of the first slide valve 70a and the second slide valve 70b is a second position and a second position, a second position and a third position, a third position and a third position, There are five stages: a third position and a first position, and a first position and a first position. The adjustment amount adjusted by the first slide valve 70a and the adjustment amount adjusted by the second slide valve 70b may be different. By finely adjusting the suction volume of the compression chamber 5a, the cooling capacity can be finely adjusted, so that the pull-down operation time can be shortened.

Embodiment 3.
FIG. 20 is a diagram showing an example of a screw compressor according to the third embodiment of the present invention. In FIG. 20, the same configurations as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted or simplified. The screw compressor 102 of this embodiment has a connecting pipe 170 and a bypass valve 172. The connecting pipe 170 corresponds to the "bypass portion" of this embodiment, and the bypass valve 172 corresponds to the "adjusting portion" of this embodiment.

The connection pipe 170 connects the medium pressure portion that becomes the medium pressure of the compression chamber 5a and the suction portion that becomes the low pressure of the compression chamber 5a. The connection pipe 170 may be any one that connects the first pressure portion of the compression chamber 5a and the second pressure portion having a pressure lower than that of the first pressure portion. The bypass valve 172 is provided in the connecting pipe 170 and adjusts the flow rate of the refrigerant flowing through the connecting pipe 170. By adjusting the opening degree of the bypass valve 172, the suction volume of the compression chamber 5a can be adjusted. That is, when the opening degree of the bypass valve 172 is increased, the suction volume of the compression chamber 5a becomes smaller.

As described above, in the screw compressor 102 of this embodiment, the bypass portion has a connecting pipe 170 connecting the first pressure portion and the second pressure portion, and the adjusting portion is provided in the connecting pipe 170. It has a bypass valve 172 that regulates the flow of the refrigerant that flows through the connecting pipe 170. By having the connection pipe 170 and the bypass valve 172, the degree of freedom in adjusting the compression ratio is improved. Further, this embodiment can be applied to a screw compressor provided with an internal volume ratio variable mechanism in which the suction volume is fixed.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. That is, the configuration of the above embodiment may be appropriately improved, or at least a part thereof may be replaced with another configuration. Further, the configuration requirement without particular limitation on the arrangement is not limited to the arrangement disclosed in the embodiment, and can be arranged at a position where the function can be achieved.

For example, the first embodiment or the second embodiment can be combined with the third embodiment. That is, the screw compressor has a configuration in which the suction volume of the compression chamber 5a is adjusted by the slide valve 7 and a configuration in which the suction volume of the compression chamber 5a is adjusted by the connection pipe 170 and the bypass valve 172. May be good.

1 Casing, 2a refrigerant, 2b motor rotor, 3a screw rotor, 3b high pressure screw rotor, 4 screw shaft, 5a compression chamber, 5b high pressure compression chamber, 6a gate rotor, 6b high pressure gate rotor, 7 slide valve, 8 connecting rod, 9 drive Equipment, 10 casings, 11 intermediate chambers, 12 discharge parts, 70 bypass openings, 70a first slide valve, 70b second slide valve, 80a first connecting rod, 80b second connecting rod, 90a first Drive device, 90b second drive device, 100 refrigeration cycle device, 101 inverter, 102 screw compressor, 103 motor, 104 heat source side heat exchanger, 105 expansion valve, 106 load side heat exchanger, 109 refrigerant circuit, 110 control Equipment, 170 connection pipes, 172 bypass valves, 200 heat source equipment, 400 load equipment.

Claims (12)

A screw rotor, a casing which forms a compression chamber together with accommodating the screw rotor the screw rotor is formed in the casing, the first pressure part and a pressure lower than the pressure of the first of said compression chamber A screw compressor provided with a bypass portion for connecting the pressure portion of 2 and an adjusting portion provided in the bypass portion for adjusting the compression ratio of the compression chamber.
A suction sensor that detects the temperature or degree of superheat of the refrigerant sucked by the screw compressor,
A control device that executes control to communicate the bypass portion before the set time elapses after the screw compressor is started and when the detection result of the suction sensor is higher than the first set value. Bei example,
The bypass portion is a heat source device in which the opening area is adjusted by sliding the adjusting portion along the rotation axis direction of the screw rotor. Before the first time elapses before the set time elapses, the control device executes control to communicate the bypass portion regardless of the detection result of the inhalation sensor.
The heat source device according to claim 1. A plurality of the bypass portions are provided.
The heat source device according to claim 1 or 2. An even number of the bypass portions are provided.
The heat source device according to claim 3. The pair of bypass portions are provided at positions symmetrical with respect to the screw rotor.
The heat source device according to claim 3 or 4. The control device controls the adjusting unit so that the compression ratio is set to the first compression ratio when the detection result of the suction sensor is a second set value higher than the first set value. When the detection result of the suction sensor is higher than the first set value and lower than the second set value, the compression ratio is set to a second compression ratio smaller than the first compression ratio. Control the adjusting unit,
The heat source device according to any one of claims 1 to 5. The bypass portion has a bypass opening formed in the casing so as to connect the first pressure portion and the second pressure portion.
The adjusting portion has a first position that covers the bypass opening so that the first pressure portion and the second pressure portion do not communicate with each other, and the first position that does not cover at least a part of the bypass opening. It has a slide valve that slides and moves a second position for communicating the pressure portion and the second pressure portion.
The heat source device according to any one of claims 1 to 6. The bypass portion has a connecting pipe connecting the first pressure portion and the second pressure portion.
The adjusting unit has a bypass valve provided in the connecting pipe to adjust the flow of the refrigerant flowing through the connecting pipe.
Heat source apparatus according to any one of claims 1 to 7. The screw compressor has a partition wall that separates a low-pressure side accommodating the compression chamber and a high-pressure side accommodating a high-pressure compression chamber that compresses a refrigerant compressed in the compression chamber.
The heat source device according to any one of claims 1 to 8. The second pressure section communicates with a suction section in which the compression chamber sucks the refrigerant.
The heat source device according to any one of claims 1 to 9. A screw rotor, a casing which forms a compression chamber together with accommodating the screw rotor the screw rotor is formed in the casing, the first pressure part and a pressure lower than the pressure of the first of said compression chamber A screw compressor provided with a bypass portion for connecting the pressure portion of 2 and an adjusting portion provided in the bypass portion for adjusting the compression ratio of the compression chamber.
Before the screw compressor has passed the first time since the start, Bei example and a control unit for executing control for communicating said bypass portion,
The bypass portion is a heat source device in which the opening area is adjusted by sliding the adjusting portion along the rotation axis direction of the screw rotor. The heat source device according to any one of claims 1 to 11.
It has a load device connected to the heat source device.
Refrigeration cycle equipment.

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