JP2012017944A - Refrigeration cycle device and method for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a drastic increase in a temperature difference between a scroll center and a circumference edge while increasing a starting speed of a scroll compressor.SOLUTION: A refrigeration cycle device is provided, including a scroll type compressor (10) compressing and discharging a refrigerant, a water-refrigerant heat exchanger (20), an expansion valve (30) with a controllable opening, and an air-refrigerant heat exchanger (40). A first temperature sensor (51, 53) detects a temperature corresponding to the temperature in the scroll center, while a second temperature sensor (52, 54) detects a temperature corresponding to the temperature in a circumference edge of the scroll. A control part (60) controls the opening of the expansion valve to prevent a temperature difference between the scroll center and the circumference edge of the scroll perimeter from exceeding a reference value.

Description

  The present invention relates to a refrigeration cycle apparatus equipped with a scroll compressor and a control method thereof.

  FIG. 6 is a diagram illustrating an example of a tooth structure of a scroll compressor. FIG. 6 shows an exploded view of the fixed scroll 1 and the orbiting scroll 2 of the scroll compressor. The scroll-type compressor is formed by combining the spiral teeth 1 a of the fixed scroll 1 and the spiral teeth 1 b of the orbiting scroll 2. The fixed scroll 1 is integrated with a housing (not shown), and the orbiting scroll 2 moves circularly by the rotation of a shaft (not shown). The refrigerant is sucked from the peripheral portion, the volume of the space for accommodating the refrigerant partitioned by both scrolls is changed, and the compressed refrigerant is discharged from the scroll center portion.

  If the high pressure or the discharge temperature is suddenly increased when the scroll compressor is operated, only the scroll central portion suddenly rises in temperature, and the temperature difference between the peripheral portion and the central portion becomes large. Therefore, only the scroll center part expands, the tooth tip comes into contact with the opposing surface, the amount of wear increases at the contact part, (1) performance degradation due to increased leakage loss, and (2) foreign matter is generated due to wear and the valve Locking due to clogging or entrapment of foreign matter, (3) seizure due to high temperature of the contact portion, and (4) if there is a tip seal at the tooth tip, the tip seal becomes hot and the performance deteriorates due to melting, etc. Sometimes.

  In the prior art, control is performed so as to prevent the occurrence of these problems by increasing the clearance of the tooth tip and preventing the tooth tip from contacting (see Patent Document 1). Alternatively, the pressure and temperature are controlled so as to increase slowly so that a large temperature distribution does not occur at the peripheral and central portions of the scroll.

JP 2007-192196 A

  However, if the clearance between the tooth tips is increased, the performance is lowered, and if the starting speed is decreased, the operation time becomes longer, both of which become inefficient. An object of this invention is to provide the refrigerating-cycle apparatus which can prevent that a temperature difference increases rapidly, and its control method, while making starting speed high.

The refrigeration cycle apparatus of the invention according to claim 1 of the present application,
A scroll compressor (10) for compressing and discharging the refrigerant;
A first heat exchanger (20) disposed downstream of the compressor (10);
A throttle valve (30) having a controllable valve opening disposed on the downstream side of the first heat exchanger (20);
A second heat exchanger (40) disposed downstream of the throttle valve;
A first temperature sensor (51, 53) for detecting a first temperature corresponding to a scroll center temperature of the scroll compressor (10);
A signal from the first temperature sensor (51, 53) is input, a value determined based on at least the first temperature is compared with a predetermined reference value, and the value is equal to or greater than the reference value. In some cases, a control unit (60) outputs a signal for controlling the opening of the throttle valve (30) to increase, or outputs a signal for controlling the opening of the throttle valve (30). When,
It is characterized by providing.

  According to the first aspect of the invention, since the expansion valve opening degree is controlled by comparing the scroll center temperature with the reference value, the temperature difference between the scroll center temperature and the peripheral temperature rapidly increases while increasing the starting speed. It is possible to prevent the increase.

The refrigeration cycle apparatus of the invention according to claim 2 is:
A second temperature sensor (52, 54) for detecting a second temperature corresponding to a scroll peripheral temperature of the scroll compressor (10);
A signal from the second temperature sensor (52, 54) is input to the control unit (60), and the control unit (60) preliminarily calculates a temperature difference between the first temperature and the second temperature. Compare with a reference value of a predetermined temperature difference, and if the temperature difference is greater than or equal to the reference value, output a signal for controlling the opening of the throttle valve (30) to be large, or the throttle valve A signal for controlling to maintain the opening degree of (30) is output.

  Thereby, it is possible to reliably prevent the temperature difference between the scroll center temperature and the peripheral temperature from rapidly increasing.

  In the refrigeration cycle apparatus of the invention according to claim 3, the first temperature is a discharge temperature of the scroll compressor (10). As a result, the temperature corresponding to the scroll center temperature can be easily detected.

  In the refrigeration cycle apparatus according to a fourth aspect of the present invention, the second temperature is an intake temperature of the scroll compressor (10). Thereby, the temperature corresponding to the scroll peripheral temperature can be easily detected.

The refrigeration cycle apparatus of the invention according to claim 5 is:
An internal heat exchanger (70) that performs heat exchange between the high-pressure refrigerant that has flowed out of the first heat exchanger (20) and the low-pressure refrigerant that flows into the scroll compressor (10);
A third temperature sensor (55) disposed on the outlet side of the second heat exchanger;
With
The temperature obtained by adding a correction amount based on the heat exchange amount of the internal heat exchanger (70) to the temperature detected by the third temperature sensor (55) is defined as the suction temperature of the scroll compressor (10).

  Thereby, in the refrigeration cycle apparatus having the internal heat exchanger (70), a temperature corresponding to the scroll peripheral temperature can be detected.

  In the refrigeration cycle apparatus of the invention according to claim 6, the correction amount is determined by the outside air temperature and the feed water temperature.

  Thereby, in the refrigeration cycle apparatus having the internal heat exchanger (70), the correction amount can be easily calculated.

  In the refrigeration cycle apparatus of the invention according to claim 7, the reference value depends on the time from the start of operation and does not decrease with time.

  Thereby, it is possible to prevent the temperature difference from rapidly increasing while increasing the startup speed.

  In the refrigeration cycle apparatus of the invention according to claim 8, the value determined based on at least the first temperature is a change amount of the first temperature per unit time.

  By looking at the amount of change in the first temperature, it is possible to prevent the temperature difference from rapidly increasing.

The refrigeration cycle apparatus of the invention according to claim 9 is:
The control unit (60) compares a change amount per unit time of the temperature difference between the first temperature and the second temperature with a reference value of a predetermined change amount of the temperature difference, and the change When the amount is equal to or greater than the reference value, a signal for controlling the opening of the throttle valve (30) to be increased or a signal for controlling the opening of the throttle valve (30) is maintained. Is output.

  Since the amount of change of the temperature difference per unit time is set as the target value, it is possible to reliably prevent an abrupt increase in temperature difference.

The refrigeration cycle control method of the invention according to claim 10 comprises:
A scroll compressor (10) for compressing and discharging the refrigerant;
A first heat exchanger (20) disposed downstream of the compressor (10);
A throttle valve (30) having a controllable valve opening disposed on the downstream side of the first heat exchanger (20);
A second heat exchanger (40) disposed downstream of the throttle valve;
A refrigeration cycle control method in a refrigeration cycle apparatus comprising:
Detecting a first temperature corresponding to a scroll center temperature of the scroll compressor (10);
Comparing a value determined based on at least the first temperature with a predetermined reference value;
When the value is greater than or equal to the reference value, a signal for controlling the opening of the throttle valve (30) to be increased or a signal for controlling to maintain the opening of the throttle valve (30) Output,
It is characterized by that.

  Thereby, it is possible to prevent the temperature difference from rapidly increasing with a simple configuration while increasing the startup speed.

The refrigeration cycle control method of the invention according to claim 11 comprises:
Detecting a second temperature corresponding to a scroll peripheral temperature of the scroll compressor (10);
Comparing a temperature difference between the first temperature and the second temperature with a reference value of a predetermined temperature difference;
When the temperature difference is equal to or greater than the reference value, a signal for controlling the opening of the throttle valve (30) to be increased is output, or the opening of the throttle valve (30) is controlled to be maintained. Output a signal.

  Thereby, it is possible to reliably prevent the temperature difference from rapidly increasing while increasing the starting speed.

  In the refrigeration cycle control method according to the twelfth aspect of the present invention, the reference value depends on time from the start of operation and does not decrease with time.

  Thereby, it is possible to reliably prevent the temperature difference from rapidly increasing while increasing the starting speed.

  In the refrigeration cycle control method according to the thirteenth aspect of the invention, the value determined based on at least the first temperature is the amount of change per unit time of the first temperature.

  Thereby, it can prevent reliably that a temperature difference increases rapidly.

In the refrigeration cycle control method of the invention according to claim 14,
The control unit (60) compares a change amount per unit time of the temperature difference between the first temperature and the second temperature with a reference value of a predetermined change amount of the temperature difference, and the change When the amount is equal to or greater than the reference value, a signal for controlling the opening of the throttle valve (30) to be increased or a signal for controlling the opening of the throttle valve (30) is maintained. Is output.

Thereby, it can prevent reliably that a temperature difference increases rapidly.
The numbers in parentheses added to the above members indicate the correspondence with the embodiments described below, and do not limit the present invention.

It is the schematic which shows the heat pump type hot-water supply apparatus containing the scroll compressor which is one Embodiment of this invention. (A) is a figure which shows the control flow of the refrigerating-cycle apparatus of this embodiment, (b) is a figure which shows the reference value of the difference of the temperature of the center part of a scroll compressor, and the temperature of a peripheral part. is there. It is a figure explaining the relationship between control of the opening degree of the expansion valve by this embodiment, and the temperature of the center part of a scroll compressor, and the temperature difference of a peripheral part. It is a figure which shows the relationship between the suction temperature and discharge temperature of a scroll compressor. It is another example of the refrigeration cycle apparatus to which the present invention is applied. It is a figure explaining the structure of the tooth | gear of a scroll compressor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a heat pump hot water supply apparatus including a scroll compressor according to an embodiment of the present invention.

  As shown in FIG. 1, the heat pump type hot water supply apparatus is a refrigeration cycle apparatus including an annular circuit having a scroll compressor 10, a water / refrigerant heat exchanger 20, an expansion valve 30, and an air heat exchanger 40. Prepare. In the refrigeration cycle apparatus, the refrigerant is sucked and discharged by the compressor 1 and circulates in the circuit. The heat pump hot water supply device heats up the water supply by supplying heat supply to the water supply via the water / refrigerant heat exchanger 20 with an amount of heat absorbed from the outside air and the amount of compression work of the compressor 1. As the refrigerant used in the present embodiment, for example, a refrigerant mainly composed of carbon dioxide can be used. In the refrigeration cycle apparatus of the present embodiment, the expansion valve 30 is used, but a refrigeration cycle apparatus using a pressure reducing valve or an ejector having the same function may be used. The “throttle valve” in the claims includes an expansion valve, a pressure reducing valve, an ejector, and the like.

  The scroll compressor 10 is an electric compressor that compresses a refrigerant by driving a compression mechanism with a built-in electric motor, and compresses and discharges an intake refrigerant whose main component is carbon dioxide to a critical pressure or higher. . The scroll compressor 10 includes a spiral fixed scroll fixed in a casing, and a spiral orbiting scroll that meshes with the fixed scroll to form a compression chamber. By turning the orbiting scroll with respect to the fixed scroll, the volume of the compression chamber is expanded and reduced, and the refrigerant can be sucked and compressed. The refrigerant is sucked from the outer peripheral portion of the scroll compressor 1, compressed, and discharged from the central portion.

  The water-refrigerant heat exchanger 20 is a high-pressure side heat exchanger that heats hot water by exchanging heat between the high-temperature refrigerant discharged from the scroll compressor 10 and hot water flowing through the water circulation passage.

  The expansion valve 30 expands the liquid-phase refrigerant or the like flowing out from the water refrigerant exchanger 20 by decompressing it in an enthalpy manner. The expansion valve 30 of the present embodiment is an electronic expansion valve, and the amount of refrigerant can be adjusted by adjusting the opening degree.

  The air refrigerant heat exchanger 40 evaporates the low-pressure refrigerant that has absorbed heat from the outside air blown by the blower 45 and has flowed out of the expansion valve 30. Note that a gas-liquid separator that separates the refrigerant into a liquid-phase refrigerant and a gas-phase refrigerant, stores excess refrigerant, and supplies the gas-phase refrigerant to the compressor 10 may be provided in the refrigeration cycle circuit.

  The control unit 60 that controls the refrigeration cycle apparatus has a computer control circuit including a processor (CPU), a memory (RAM), a nonvolatile memory (ROM), and the like. In order to determine the control conditions of the refrigeration cycle apparatus in the present embodiment, signals from the temperature sensors 51 to 54 are input to the control unit 70, and a signal for controlling the opening degree of the expansion valve 30 as a result of processing by the control unit 70 Is output. The temperature sensor 51 detects the temperature at the center of the scroll compressor 10, and the temperature sensor 52 detects the temperature at the peripheral edge of the scroll compressor 10. The temperature sensor 53 detects the discharge temperature of the scroll compressor 10, and the temperature sensor 54 detects the suction temperature of the scroll compressor 10.

  The scroll compressor 10 moves the plurality of compression chambers defined between the spiral tooth portions of the orbiting scroll and the fixed scroll to the center by the orbiting motion of the orbiting scroll to reduce its volume, Compression is performed. Therefore, if the high pressure or the discharge temperature is suddenly increased when the scroll compressor is operated, only the scroll center portion suddenly increases in temperature, and the temperature difference between the peripheral portion and the center portion becomes large. In the present embodiment, the refrigeration cycle apparatus is controlled so that the temperature difference between the peripheral portion and the central portion does not increase and the starting speed is increased.

  Fig.2 (a) is a figure which shows the control flow of the refrigerating-cycle apparatus of this embodiment, FIG.2 (b) is a reference value of the difference of the temperature of the center part of a scroll type compressor, and the temperature of a peripheral part. FIG. Each step of the control flow in FIG. 2 is executed by the control unit 60.

  When the operation of the scroll compressor is started, for example, control for narrowing the opening of the expansion valve 30 is performed toward the target value of the discharge temperature. In step S <b> 1, the temperature T <b> 1 of the peripheral portion of the scroll compressor 10 is obtained from a signal from the temperature detector 52 that detects the temperature of the peripheral portion of the scroll compressor 10. Further, the temperature T2 at the center of the scroll compressor 10 is obtained from a signal from the temperature detector 51 that detects the temperature at the center of the scroll compressor 10.

  In step S2, the temperature T1 at the peripheral portion is subtracted from the temperature T2 at the central portion to calculate a difference T3 between the temperature T2 at the central portion and the temperature T1 at the peripheral portion.

  In step S3, the calculated temperature difference T3 is compared with a reference value T0 that is determined in advance according to the elapsed time since the start of the scroll compressor. FIG. 2B shows an example of the reference value T0. The vertical axis of the graph of FIG. 2B indicates a reference value (° C.) of the difference between the temperature at the center and the peripheral temperature of the scroll compressor, and the horizontal axis indicates time (minutes). In the example of FIG. 2B, the temperature is increased linearly from the start of operation until t1 and is kept constant until t2 is reached, and after t2, the temperature is increased linearly again. To control. Note that the reference value in FIG. 2B is merely an example, and the temperature may be increased linearly without taking the time for keeping the constant temperature, or the time for keeping the constant temperature may be a plurality of stages.

  In step S3, if the temperature difference T3 is smaller than the reference value T0, the process returns to step 1. If the temperature difference T3 is greater than or equal to the reference value T0, in step S4, the opening degree of the expansion valve 30 is increased or the opening degree of the expansion valve is maintained. Thereby, expansion of the temperature difference of the center part and peripheral part of a scroll compressor can be suppressed. Thereafter, the process returns to step S1.

  FIG. 3 is a diagram for explaining the relationship between the control of the opening degree of the expansion valve according to the present embodiment and the temperature difference between the central portion and the peripheral portion of the scroll compressor.

  In the graph of temperature difference and time shown in the upper part of FIG. 3, the graph of the reference value T0 is indicated by a broken line. The solid line in FIG. 3 shows the result of control using the reference value T0 shown in FIG. 3 and the temperature difference between the scroll center and the scroll peripheral edge in FIG. 2 as the target value. The dotted line in FIG. 3 shows the result of not performing the control in FIG.

  In the graph of the valve opening and time shown in the lower part of FIG. 3, the solid line indicates the transition of the valve opening along the time when the control of FIG. 2 is performed, and the broken line performs the control of FIG. 2. The change of the valve opening along the time when there was not is shown.

  Referring to FIG. 3, after the operation of the scroll compressor is started, the valve opening is controlled to be gradually reduced. At a certain time t3, the temperature difference between the scroll center and the scroll peripheral edge exceeds the reference value. When the temperature difference between the scroll center portion and the scroll peripheral portion is equal to or greater than the reference value, the control according to the present embodiment increases the expansion valve opening or maintains the opening as shown in FIG. Thereby, the temperature difference between the scroll center portion and the scroll peripheral portion is prevented from becoming large. Subsequently, control is performed to increase the opening degree of the expansion valve or to maintain the opening degree until time t2. When the time t2 has passed, control is performed to throttle the expansion valve opening again. As can be seen from the solid line in the temperature difference-time graph of FIG. 3, in the control according to the present embodiment, the opening degree of the expansion valve is reduced so as not to exceed the reference value. Moreover, since the opening degree of the expansion valve can be rapidly reduced until time t3, it is possible to prevent the temperature difference from rapidly increasing while increasing the starting speed.

  The dotted line of the valve opening graph in FIG. 3 shows the case where the control of the present embodiment is not performed and the opening of the expansion valve is throttled as usual even when the time t3 is exceeded. When the opening degree control of the expansion valve as shown by the dotted line is performed, the temperature difference between the scroll center part and the scroll peripheral part further expands, and as shown by the dotted line in the temperature difference graph of FIG. The temperature difference exceeds the reference value. In this case, the temperature difference between the scroll center portion and the scroll peripheral portion becomes excessive, the tooth tip of the scroll center portion expands and protrudes, and tooth tip contact occurs, causing various problems. According to the control of this embodiment, the expansion of the tooth tip due to the temperature difference between the scroll center portion and the scroll peripheral portion can be suppressed.

  In the flow of FIG. 2, the temperature T2 at the center of the scroll compressor 10 is obtained by the temperature detector 51 that detects the temperature at the center, and the temperature T1 at the periphery of the scroll compressor 10 is the temperature at the periphery. It is obtained by the temperature detector 52 that detects the above. However, it is often difficult to dispose the temperature detector 51 that detects the temperature of the central portion.

  FIG. 4 is a diagram showing the relationship between the suction temperature and the discharge temperature of the scroll compressor. The temperature T2 at the center of the scroll compressor 10 can be substituted by the discharge temperature of the scroll compressor 10 indicated by the discharge refrigerant temperature of the scroll compressor 10 or the discharge side pipe temperature. That is, the discharge temperature detected by the temperature sensor 53 disposed on the discharge side of the scroll compressor 10 can be regarded as the temperature T2 at the center of the scroll compressor 10. In this way, it is not necessary to arrange the temperature sensor 51 at the center of the scroll compressor 10.

  Further, the temperature T1 at the peripheral edge of the scroll compressor 10 can be substituted by the suction temperature of the scroll compressor 10, that is, the suction refrigerant temperature or the suction side pipe temperature. That is, the suction temperature detected by the temperature sensor 54 disposed on the suction side of the scroll compressor 10, in other words, the outflow side of the air refrigerant heat exchanger, is regarded as the temperature T 1 of the peripheral portion of the scroll compressor 10. Can do.

  In this embodiment, the expansion valve opening degree is controlled with the temperature difference between the scroll center and the scroll peripheral part as a target value. As shown in FIG. 4, the scroll compressor corresponding to the temperature of the scroll peripheral part is used. The suction temperature of the gas is almost constant compared to the discharge temperature. Therefore, the temperature at the center of the scroll or the discharge temperature of the scroll compressor can be set as the target value. This is because the temperature at the scroll peripheral part does not change so much, so the temperature at the scroll central part or the discharge temperature of the scroll compressor is considered to indicate the temperature difference between the scroll central part and the scroll peripheral part.

  Further, in the present embodiment, a reference temperature determined in accordance with the elapsed time from the start of the scroll compressor 10 is adopted as the reference temperature compared with the temperature difference between the scroll center portion and the scroll peripheral portion. However, a reference value is provided for the change amount of the temperature difference per unit time, the change amount of the temperature difference obtained from the detector is calculated, and when the change amount exceeds the reference value, the expansion valve 30 is opened. You may make it control whether a degree is maintained or enlarged.

  As described above, in this embodiment, since the temperature difference between the scroll center portion and the scroll peripheral portion is suppressed from rapidly expanding, only the scroll center portion expands and the tooth tip contact occurs as in the conventional case. The amount of wear does not increase at the contact portion. Therefore, (1) performance degradation due to increased leakage loss, (2) foreign matter is generated due to wear and the valve is clogged or locked due to foreign matter biting, (3) seizure due to high temperature of the contact part, (4) tip seal on tooth tip If there is, it is possible to prevent problems such as performance degradation due to melting of the chip seal due to high temperature.

  FIG. 5 is another example of a refrigeration cycle apparatus to which the present invention is applied. FIG. 5 is a diagram showing an example in which an internal heat exchanger is added to the refrigeration cycle apparatus of FIG.

  The internal heat exchanger 70 performs heat exchange between the high-pressure refrigerant that has flowed out of the water-refrigerant heat exchanger 20 and the low-pressure refrigerant that flows into the compressor 10. The internal heat exchanger 70 integrally includes a high-pressure refrigerant flow path through which the high-pressure refrigerant flows and a low-pressure refrigerant flow path through which the low-pressure refrigerant flows. The flow direction of the refrigerant flowing through the high-pressure refrigerant flow path and the low-pressure refrigerant flow path It is comprised so that the flow direction of the refrigerant | coolant which flows through may oppose. By reducing the temperature of the high-pressure refrigerant at the inlet of the expansion valve 30 with the internal heat exchanger 70, the gasification of the refrigerant when the pressure is reduced is suppressed, and the heat absorption amount of the air refrigerant heat exchanger 40 is increased to increase the efficiency. Can do.

  In the refrigeration cycle apparatus including the internal heat exchanger 70, the temperature detection sensor 55 is provided on the outlet side of the air refrigerant heat exchanger 40, and the temperature of the air refrigerant heat exchanger 40 or the outlet side of the air refrigerant heat exchanger 40 is provided. Detect the temperature. A temperature obtained by correcting the temperature detected by the temperature detection sensor 55 with the heat exchange amount of the internal heat exchanger 70 can be used as the suction temperature of the scroll compressor 10, and the temperature T 1 at the peripheral edge of the scroll compressor 10 can be obtained. It can be used instead. In this way, even in the refrigeration cycle apparatus having the internal heat exchanger 70, the intake temperature of the scroll compressor 10 can be easily detected.

  Since the heat exchange amount of the internal heat exchanger 70 is determined by the outside air temperature and the feed water temperature, the outside air temperature and the feed water temperature are detected and input to the control unit 60, and the internal heat is based on the outside air temperature and the feed water temperature. The heat exchange amount of the exchanger 70 can be calculated. As for the outside air temperature, for example, an outside air temperature sensor can be arranged around the air refrigerant heat exchanger 40 to detect the outside air temperature. Moreover, about a feed water temperature, a feed water temperature sensor can be arrange | positioned in the entrance of the feed passage of the water refrigerant | coolant heat exchanger 20, and a feed water temperature can be detected.

DESCRIPTION OF SYMBOLS 1 Fixed scroll 1a Fixed scroll tooth 2 Moveable scroll 2a Fixed scroll tooth 10 Scroll type compressor 20 Water refrigerant heat exchanger 30 Expansion valve 40 Air heat exchanger 51 Temperature sensor of scroll center part 52 Temperature sensor 53 of scroll peripheral part Scroll compressor discharge temperature 54 Scroll compressor suction temperature 60 Control unit 70 Internal heat exchanger

Claims (14)

A scroll compressor (10) for compressing and discharging the refrigerant;
A first heat exchanger (20) disposed downstream of the compressor (10);
A throttle valve (30) having a controllable valve opening disposed on the downstream side of the first heat exchanger (20);
A second heat exchanger (40) disposed downstream of the throttle valve;
A first temperature sensor (51, 53) for detecting a first temperature corresponding to a scroll center temperature of the scroll compressor (10);
When the signal from the first temperature sensor is input and a value determined based on at least the first temperature is compared with a predetermined reference value, and the value is equal to or greater than the reference value, the throttle valve A control unit (60) for outputting a signal for controlling to increase the opening of (30) or outputting a signal for controlling to maintain the opening of the throttle valve (30);
A refrigeration cycle apparatus comprising: A second temperature sensor (52, 54) for detecting a second temperature corresponding to a scroll peripheral temperature of the scroll compressor (10);
A signal from the second temperature sensor (52, 54) is input to the control unit (60), and the control unit (60) preliminarily calculates a temperature difference between the first temperature and the second temperature. Compare with a reference value of a predetermined temperature difference, and if the temperature difference is greater than or equal to the reference value, output a signal for controlling the opening of the throttle valve (30) to be large, or the throttle valve The refrigeration cycle apparatus according to claim 1, wherein a signal for controlling the opening degree of (30) is output.   The refrigeration cycle apparatus according to claim 1 or 2, wherein the first temperature is a discharge temperature of the scroll compressor (10).   The refrigeration cycle apparatus according to claim 2 or 3, wherein the second temperature is a suction temperature of the scroll compressor (10). An internal heat exchanger (70) that performs heat exchange between the high-pressure refrigerant that has flowed out of the first heat exchanger (20) and the low-pressure refrigerant that flows into the scroll compressor (10);
A third temperature sensor (55) disposed on the outlet side of the second heat exchanger;
With
The temperature obtained by adding a correction amount based on the heat exchange amount of the internal heat exchanger (70) to the temperature detected by the third temperature sensor (55) is set as the suction temperature of the scroll compressor (10). The refrigeration cycle apparatus described in 1.   The refrigeration cycle apparatus according to claim 5, wherein the correction amount is determined by an outside air temperature and a water supply temperature.   The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein the reference value depends on time from the start of operation and does not decrease with time.   The refrigeration cycle apparatus according to claim 1, wherein the value determined based on at least the first temperature is a change amount of the first temperature per unit time.   The control unit (60) compares a change amount per unit time of the temperature difference between the first temperature and the second temperature with a reference value of a predetermined change amount of the temperature difference, and the change When the amount is equal to or greater than the reference value, a signal for controlling the opening of the throttle valve (30) to be increased or a signal for controlling the opening of the throttle valve (30) is maintained. The refrigeration cycle apparatus according to claim 2, wherein A scroll compressor (10) for compressing and discharging the refrigerant;
A first heat exchanger (20) disposed downstream of the compressor (10);
A throttle valve (30) having a controllable valve opening disposed on the downstream side of the first heat exchanger (20);
A second heat exchanger (40) disposed downstream of the throttle valve;
A refrigeration cycle control method in a refrigeration cycle apparatus comprising:
Detecting a first temperature corresponding to a scroll center temperature of the scroll compressor (10);
Comparing a value determined based on at least the first temperature with a predetermined reference value;
When the value is greater than or equal to the reference value, a signal for controlling the opening of the throttle valve (30) to be increased or a signal for controlling to maintain the opening of the throttle valve (30) Output,
A refrigeration cycle control method characterized by the above. Detecting a second temperature corresponding to a scroll peripheral temperature of the scroll compressor (10);
Comparing a temperature difference between the first temperature and the second temperature with a reference value of a predetermined temperature difference;
When the temperature difference is equal to or greater than the reference value, a signal for controlling the opening of the throttle valve (30) to be increased is output, or the opening of the throttle valve (30) is controlled to be maintained. The refrigeration cycle control method according to claim 10, wherein a signal is output.   The refrigeration cycle control method according to any one of claims 10 and 11, wherein the reference value depends on time from the start of operation and does not decrease with time.   The refrigeration cycle control method according to claim 10, wherein the value determined based on at least the first temperature is a change amount of the first temperature per unit time.   The control unit (60) compares a change amount per unit time of the temperature difference between the first temperature and the second temperature with a reference value of a predetermined change amount of the temperature difference, and the change When the amount is equal to or greater than the reference value, a signal for controlling the opening of the throttle valve (30) to be increased or a signal for controlling the opening of the throttle valve (30) is maintained. The refrigeration cycle control method according to claim 10, wherein the refrigeration cycle is output.

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