JP7387057B2 - Refrigeration cycle equipment - Google Patents

Description

The present disclosure relates to a refrigeration cycle device.

Conventionally, refrigeration cycle devices are known that have a function of preventing a compressor from being started in a state where refrigerant is dissolved in lubricating oil within the compressor.

In Patent Document 1, the refrigerant may dissolve into the lubricating oil of the compressor while the refrigeration cycle device is stopped for a long period of time, so when restarting the refrigeration cycle device, the lubricating oil is heated to quench the refrigerant. A technique is disclosed in which the compressor is started after sufficient evaporation.

Japanese Patent Application Publication No. 5-312419

According to the technology described in Patent Document 1, the compressor can be started after the refrigerant gradually dissolved in the lubricating oil over a long period of time is changed from liquid to gas, so the starting torque when starting the compressor is reduced. Abnormal increase can be prevented.

However, the phenomenon in which the refrigerant flows into the compressor in a liquid state does not occur only when the refrigeration cycle apparatus is stopped for a long period of time, but can also occur during operation of the refrigeration cycle. During operation of the refrigeration cycle, the compressor is repeatedly stopped and restarted depending on the target temperature. When a stopped compressor is restarted, the pressure on the discharge side of the compressor increases and the refrigerant in the refrigerant circuit begins to circulate. At this time, unvaporized liquid refrigerant may flow into the compressor from the suction side of the compressor.

This phenomenon occurs because the pressure in the refrigerant circuit on the suction side of the compressor rapidly changes from low pressure to high pressure as the compressor is started. As the pressure in the refrigerant circuit on the suction side of the compressor increases rapidly, the pressure reducing device installed in the refrigerant circuit cannot follow the pressure increase, and the refrigerant in the refrigerant circuit does not completely evaporate and remains in liquid form. There is a risk that it will return to the compressor. At this time, a large torque load may be applied to the compressor, and the compressor, which is transitioning from a stopped state to a started state, cannot be controlled to follow changes in pressure, and the compressor does not operate normally. there is a possibility.

The present disclosure has been made to solve such problems, and the purpose is to prevent the operation of the compressor by causing refrigerant to suddenly flow in from the suction side of the compressor when starting the compressor. An object of the present invention is to provide a refrigeration cycle device that prevents problems from occurring.

The refrigeration cycle device in the present disclosure includes a compressor, a first heat exchanger, a second heat exchanger, a pressure reduction device, a compressor, a first heat exchanger, a pressure reduction device, and a second heat exchanger in this order. It includes a circulation path that circulates refrigerant, a control device that controls the compressor, and a pressure sensor that is placed on the suction side of the compressor and detects the pressure in the circulation path. The pressure reducing device is configured to be able to switch the circulation path between an open state and a closed state. The control device starts the compressor when the pressure increase rate specified based on the detected value of the pressure sensor is less than a threshold value when the pressure reducing device switches the circulation route from a closed state to an open state.

According to the present disclosure, it is possible to realize a refrigeration cycle device that prevents malfunctions in the operation of the compressor due to sudden inflow of refrigerant from the suction side of the compressor when the compressor is started.

1 is a diagram showing the configuration of a refrigeration cycle device in Embodiment 1. FIG. It is a figure which shows the detection value of a pressure sensor before and after a low-pressure cut. It is a flowchart which restarts a compressor according to the detection value of a pressure sensor. It is a flowchart of a modification of restarting a compressor according to a detection value of a pressure sensor. It is a figure showing the composition of the refrigeration cycle device in Embodiment 2. It is a flowchart which restarts a compressor after closing the electromagnetic valve arranged in the heat source side unit. It is a flowchart of a modification in which the compressor is restarted after the solenoid valve disposed in the heat source side unit is closed.

Hereinafter, embodiments of the technical idea according to the present disclosure will be described with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

Embodiment 1.
<Configuration of refrigeration cycle device>
FIG. 1 is a diagram showing the configuration of a refrigeration cycle device 10 in the first embodiment. The refrigeration cycle device 10 according to the first embodiment is typically an air conditioner, a freezer, or the like. The refrigeration cycle device 10 includes a heat source side unit 100 and a load side unit 200. The heat source side unit 100 is, for example, a condensing unit (refrigeration machine), and specifically, an outdoor unit. The load side unit 200 is, for example, an indoor unit such as a showcase or a unit cooler.

The refrigeration cycle device 10 includes a refrigerant circuit in which a compressor 1, a first heat exchanger 2, a pressure reducing device 3, and a second heat exchanger 4 are sequentially connected. The pressure reducing device 3 includes an expansion valve 31 and a solenoid valve 22. The refrigeration cycle device 10 circulates refrigerant through the compressor 1 , the first heat exchanger 2 , the pressure reducing device 3 , and the second heat exchanger 4 in this order. Hereinafter, the path through which the refrigerant circulates will be referred to as a "circulation path." The refrigerant circulating in the circulation path exchanges heat with air in the first heat exchanger 2 and the second heat exchanger 4. Thereby, the refrigeration cycle device 10 lowers the temperature of the air around the load-side unit 200, which is an indoor unit. Below, the temperature of the air around the load-side unit 200 may be simply referred to as "the temperature of the load-side unit 200."

The heat source side unit 100 includes a compressor 1 , a first heat exchanger 2 , a pressure sensor 6 , and a control device 7 . The load side unit 200 includes a pressure reducing device 3 and a second heat exchanger 4. A liquid pipe 20 and a gas pipe 21 are provided between the heat source side unit 100 and the load side unit 200. The liquid pipe 20 allows liquid refrigerant to flow from the heat source side unit 100 to the load side unit 200. Hereinafter, a liquid refrigerant may be simply referred to as a liquid refrigerant. The gas pipe 21 allows gaseous refrigerant to flow from the load side unit 200 to the heat source side unit 100. Hereinafter, a gaseous refrigerant may be simply referred to as a gas refrigerant. The first heat exchanger 2 corresponds to the "first heat exchanger" in the present disclosure, the second heat exchanger 4 corresponds to the "second heat exchanger" in the present disclosure, and the pressure reducing device 3 corresponds to the "second heat exchanger" in the present disclosure. Corresponding to the "pressure reducing device" in the disclosure, the solenoid valve 22 corresponds to the "first switching device" in the present disclosure.

Below, the configuration arranged in the circulation path of the refrigeration cycle device 10 will be explained in the order in which the refrigerant is circulated starting from the compressor 1. Direction D indicates the direction in which the refrigerant flows.

Compressor 1 is configured to compress refrigerant within a refrigerant circuit. The compressor 1 may be a constant speed compressor with a constant compression capacity, or may be an inverter compressor with a variable compression capacity. The inverter compressor is configured to variably control the rotation speed. Specifically, the drive frequency of the inverter compressor is changed based on instructions from the control device 7. As a result, the rotation speed of the inverter compressor is adjusted and the compression capacity changes. Compression capacity is the amount of refrigerant pumped out per unit time. The refrigerant discharged from the compressor 1 becomes a high-temperature, high-pressure superheated gas.

The first heat exchanger 2 is connected to the discharge side of the compressor 1. The first heat exchanger 2 radiates heat to fins and the like to condense the refrigerant. Therefore, the first heat exchanger 2 functions as a condenser. The refrigerant passing through the first heat exchanger 2 exchanges heat with the air surrounding the first heat exchanger 2 due to forced convection generated by a fan (not shown) provided in the heat source side unit 100. Thereby, the refrigerant passing through the first heat exchanger 2 is condensed and becomes a medium-temperature, high-pressure liquid. Medium temperature and high pressure liquid refrigerant flows from the heat source side unit 100 to the load side unit 200 via the liquid pipe 20.

The electromagnetic valve 22 is arranged between the first heat exchanger 2 and the expansion valve 31. The solenoid valve 22 switches the circulation path between an open state and a closed state. Typically, solenoid valve 22 is a two-way valve. The expansion valve 31 expands the refrigerant. The refrigerant expanded by the expansion valve 31 enters a gas-liquid two-phase state at low temperature and low pressure. The electromagnetic valve 22 and the expansion valve 31 may be provided as an integrated device.

The second heat exchanger 4 evaporates the refrigerant in a gas-liquid two-phase state at low temperature and low pressure. That is, the low-temperature, low-pressure, gas-liquid two-phase refrigerant exchanges heat with the air surrounding the second heat exchanger 4 or with a liquid such as water. The refrigerant evaporated by the second heat exchanger 4 becomes a low-pressure superheated gas. Therefore, the second heat exchanger 4 functions as an evaporator. The refrigerant in a low-pressure superheated gas state flows from the load side unit 200 to the heat source side unit 100 via the gas pipe 21. In this way, in the refrigeration cycle device 10, a circulation path through which the refrigerant circulates is formed.

In the heat source side unit 100, the pressure sensor 6 is provided in the circulation path on the suction side of the compressor 1. In other words, the pressure sensor 6 is provided between the gas pipe 21 and the compressor 1. The pressure sensor 6 detects the pressure within the circulation path at the position where the pressure sensor 6 is provided. The pressure sensor 6 transmits information including the detected value of the pressure within the circulation path to the control device 7.

The control device 7 controls the compressor 1 using the pressure detected by the pressure sensor 6. The control device 7 is connected to the pressure sensor 6 and the compressor 1. The control device 7 includes a CPU 71 (Central Processing Unit), a storage device 72 (including, for example, a ROM and a RAM), an input/output buffer, and the like. The control device 7 starts and stops the compressor 1 by having the CPU execute a program stored in the storage device 72 . In the present disclosure, a state in which the control device 7 starts the compressor 1 may be referred to as a "starting state", and a state in which the control device 7 stops the compressor 1 may be referred to as a "stopped state". be. Moreover, although a prescribed threshold value, a prescribed temperature, a prescribed pressure, a prescribed period, etc. will be explained below, these parameters are stored in advance in the storage device 72 of the control device 7. The specified threshold value, specified temperature, specified pressure, specified period, etc. may be stored by an external device that can communicate with the control device 7. The prescribed threshold value, prescribed temperature, prescribed pressure, and prescribed period can be determined based on experiments and the like.

The control device 7 includes a display 8 . The display 8 is composed of, for example, a 7-segment LED. The display 8 can display the status of the control device 7 and the like. The control device 7 is provided within the heat source side unit 100. The control device 7 may be provided in a unit separate from the heat source side unit 100.

Load side unit 200 includes a temperature detector 25. Specifically, the temperature detector 25 is a thermistor or the like provided to detect the temperature of the load side unit 200. The solenoid valve 22 and the temperature detector 25 are connected. The solenoid valve 22 is configured to switch the state of the circulation path according to the temperature detected by the temperature detector 25. The solenoid valve 22 may be controlled by a control device (not shown) provided in the load-side unit 200.

When the temperature of the load-side unit 200 falls below a prescribed lower limit temperature, the solenoid valve 22 switches the circulation path through which the refrigerant circulates to a closed state. Thereby, in the refrigeration cycle device 10, the circulation of the refrigerant is stopped, and the temperature of the load-side unit 200 is prevented from lowering more than necessary.

Further, when the temperature of the load-side unit 200 exceeds the specified upper limit temperature, the solenoid valve 22 switches the circulation path through which the refrigerant circulates to an open state. Thereby, in the refrigeration cycle device 10, circulation of the refrigerant starts, and it is possible to prevent the temperature of the load-side unit 200 from increasing.

<Control according to the detected value of pressure sensor 6>
With reference to FIG. 2, an example of controlling the closed state or open state of the circulation path using the pressure sensor 6 will be described. FIG. 2 is a diagram showing the detected values of the pressure sensor 6 before and after the low pressure cut. Low pressure cut is a control that stops the compressor 1 when the detected value of the pressure sensor 6 decreases based on the temperature of the load side unit 200 decreasing and the circulation path being closed by the solenoid valve 22. means. The control device 7 stops the compressor 1 when the temperature of the load side unit 200 decreases due to the low pressure cut. Below, low-pressure cutting will be explained in detail using FIG. 2. In FIG. 2, the vertical axis indicates the detected value of the pressure sensor 6, and the horizontal axis indicates the elapsed time.

Before time Ta, in the refrigeration cycle device 10, the compressor 1 is started and the solenoid valve 22 opens the circulation path. That is, before time Ta, the compressor 1 compresses the refrigerant at a constant pressure and discharges the refrigerant. Heat exchange occurs between the refrigerant and the air around the second heat exchanger 4, and the air in the load side unit 200 is cooled.

Subsequently, at time Ta, the temperature of the cooled load-side unit 200 falls below the specified lower limit temperature. That is, in order to prevent the temperature of the load-side unit 200 from dropping more than necessary, the electromagnetic valve 22 can switch the circulation path from an open state to a closed state by the load-side unit 200. Therefore, the circulation of the refrigerant stops. The flow rate of the refrigerant decreases after the circulation path becomes blocked. As shown in FIG. 2, the detection value of the pressure sensor 6 gradually decreases as the flow rate of the refrigerant decreases.

At time Tb, the detection value of the pressure sensor 6 reaches the low pressure cut value. The low pressure cut value is a prescribed pressure value for the control device 7 to perform low pressure cut. That is, the control device 7 executes a low pressure cut, which is a control to stop the compressor 1, when the detected value of the pressure sensor 6 becomes the low pressure cut value.

Thereby, even when the circulation path is switched to the closed state by the electromagnetic valve 22 in the load side unit 200, the control device 7 stops the compressor 1 based on the pressure sensor 6 of the heat source side unit 100. That is, the control device 7 does not need to be connected to the load side unit 200.

After the compressor 1 stops at time Tb, the temperature of the load-side unit 200 gradually increases. As a result, the temperature of the load-side unit 200 exceeds the specified upper limit temperature at time Tc. That is, after time Tc, the refrigeration cycle device 10 needs to start circulating the refrigerant again.

At time Tc, in order to prevent the temperature of the load-side unit 200 from rising beyond the upper limit temperature, the solenoid valve 22 switches the circulation path from the closed state to the open state. Although the compressor 1 is stopped, the refrigerant that has been blocked by the solenoid valve 22 flows into the heat source unit 100 because the circulation path is opened. Therefore, as shown in FIG. 2, the detected value of the pressure sensor 6 after time Tc rises steeply.

At time Tc, after the solenoid valve 22 switches the circulation path to the open state, the control device 7 starts the compressor 1. The control device 7 determines whether preparations for starting the compressor 1 are complete. In other words, the control device 7 determines whether the compressor 1 is in a ready state. The preparation state is a state indicating whether or not the compressor 1 is in a state before starting up. When the compressor 1 is in the preparation state, the control device 7 determines that the compressor 1 is in a pre-start stage.

In the example of FIG. 2, it is determined whether the compressor 1 is in the preparation state based on the low pressure cut return value. The low pressure cut return value is a prescribed pressure value stored by the storage device 72. The low pressure cut return value is a value higher than the low pressure cut value. As described above, the detection value of the pressure sensor 6 rises steeply from time Tc. At time Td, the detected value of the pressure sensor 6 becomes the low pressure cut return value. Thereby, the control device 7 determines that the compressor 1 is in the preparation state.

After determining that the compressor 1 is in the preparation state, the control device 7 compares the rate of increase in pressure specified based on the detected value of the pressure sensor 6 with a threshold value. Hereinafter, the pressure increase rate specified based on the detected value of the pressure sensor 6 will be simply referred to as the "increase rate." Specifically, the control device 7 starts the compressor 1 when the rising speed becomes less than a prescribed threshold value V1.

A method other than the method using the low pressure cut return value may be used as a condition for entering the preparation state. For example, the control device 7 determines that the compressor 1 has entered the preparation state based on the fact that a prescribed period of time has passed since the low pressure was cut.

In FIG. 2, the rate of rise at time Te is shown as velocity Ve. That is, the speed Ve is the slope of the tangent to the curve shown in FIG. 2 at time Te. In other words, the rising speed is the amount of change in the detected value of the pressure sensor 6 per unit time. The speed Ve is a speed greater than or equal to the threshold value V1. Therefore, the control device 7 does not start the compressor 1 because the speed Ve at the time Te is not less than the threshold value V1.

Since the velocity Ve at the time Te is a pressure equal to or higher than the threshold value V1, the refrigerant rapidly flows into the heat source side unit 100 at the time Te. Therefore, when the stopped compressor 1 is started again at time Te, there is a possibility that a large amount of unvaporized liquid refrigerant flows into the compressor 1 from the load-side unit 200.

When liquid refrigerant flows into the compressor 1 that is transitioning from a stopped state to a started state, the control such as feedback in the compressor 1 cannot follow the flow, so the resistance that occurs when driving the compressor 1 is caused by the resistance in the liquid refrigerant. can increase in As a result, the compressor 1 may not operate normally. Therefore, the control device 7 controls the compressor 1 not to start during the time Te when the speed Ve is equal to or higher than the threshold value V1.

Next, attention will be paid to time Tf. At time Tc, after the electromagnetic valve 22 is switched to the open state, the detected value of the pressure sensor 6 converges to a pressure corresponding to the temperature of the load-side unit 200. That is, the rate of increase in the detected value of the pressure sensor 6 gradually decreases. As shown in FIG. 2, the speed Vf indicates the rising speed at time Tf. The speed Vf is a speed less than the threshold value V1. Therefore, at time Tf, the control device 7 starts the compressor 1 because the speed Vf is less than the threshold value V1.

In other words, the control device 7 of the refrigeration cycle device 10 in this embodiment determines whether to start the compressor 1 by paying attention to the rising speed after the compressor 1 is in the preparation state. Thereby, the control device 7 prevents the refrigerant circuit from flowing liquid refrigerant into the compressor 1 which is in transition from the stopped state to the activated state. That is, in the refrigeration cycle device 10 of the first embodiment, when the compressor 1 is started, it is possible to prevent the refrigerant from suddenly flowing in from the suction side of the compressor 1 and causing a malfunction in the operation of the compressor 1.

<Control flow for restarting compressor 1>
FIG. 3 is a flowchart for restarting the compressor 1 according to the detected value of the pressure sensor 6. Below, a control flow of the control device 7 for restarting the compressor 1 after the compressor 1 is stopped by the low pressure cut explained in FIG. 2 will be shown. The control device 7 executes a low pressure cut (step S11). That is, the control device 7 stops the compressor 1 because the electromagnetic valve 22 of the load side unit 200 is switched and the circulation path is closed.

Subsequently, the control device 7 determines whether the compressor 1 is in a ready state (step S12). That is, the control device 7 determines whether the detected value of the pressure sensor 6 is a low pressure cut return value. When determining that the compressor 1 is not in the preparation state because the detected value of the pressure sensor 6 is not the low pressure cut return value (NO in step S12), the control device 7 stops the process at step S12.

When the detected value of the pressure sensor 6 becomes the low pressure cut return value and it is determined that the compressor 1 is in the preparation state (YES in step S12), the control device 7 determines whether the rising speed is less than the threshold value V1. (Step S13). If the rising speed is less than the threshold value V1 (YES in step S13), the control device 7 starts the compressor 1 (step S14) and ends the process. That is, when the rising speed is less than the threshold value V1, the refrigerant does not suddenly flow in from the suction side of the compressor 1, so the compressor 1 can be started.

If the rising speed is not less than the threshold value V1 (NO in step S13), the control device 7 executes a standby process for the compressor 1 (step S15). That is, the control device 7 puts the compressor 1 on standby for a prescribed period. It is desirable that the prescribed waiting period be short. After the standby process ends, the control device 7 compares the rising speed with the threshold value again.

The control device 7 determines whether the rising speed is less than the threshold value V1 (step S16). The threshold value to be compared in step S16 may be a different value from the threshold value in step S13. For example, the threshold value to be compared in step S16 may be a threshold value V2 that is lower than the threshold value V1. In step S16, the compressor 1 is undergoing standby processing, so it is expected that the rising speed in step S16 is lower than the rising speed in step S13. Specific values of the threshold value V1 and the threshold value V2 can be determined based on experiments.

If the rising speed is not less than the threshold value V1 (NO in step S16), the control device 7 returns the process to step S15. Thereby, the control device 7 causes the compressor 1 to wait until the rising speed becomes less than the threshold value V1. If the rising speed is less than the threshold value V1 (YES in step S16), the control device 7 starts the compressor 1 (step S14) and ends the process.

In this way, the control device 7 compares the rising speed with the threshold value after the compressor 1 is in the ready state. As a result, in the refrigeration cycle device 10, it is possible to prevent the refrigerant from suddenly flowing into the compressor 1 from the suction side during the transition from the stopped state to the starting state, and causing a malfunction in the operation of the compressor 1. can.

<Modification of Embodiment 1>
Below, a modification of the control flow for restarting the compressor 1 shown in FIG. 3 will be shown. In FIG. 3, an example has been described in which the control device 7 starts the compressor 1 when the solenoid valve 22 switches the circulation path from the closed state to the open state and the rising speed is less than the threshold value V1.

In a modification of Embodiment 1, after the control device 7 switches the circulation path from the closed state to the open state using the electromagnetic valve 22, the rising speed does not fall below the first threshold value until the first period has elapsed. An example of starting the compressor 1 in this case will be explained using FIG. FIG. 4 is a flowchart of a modification example in which the compressor 1 is restarted according to the detected value of the pressure sensor 6. In the flowchart of FIG. 4, descriptions of configurations that overlap with those of the flowchart of FIG. 3 will not be repeated.

In FIG. 4, if the rising speed is not less than the threshold V1 in step S16, the control device 7 determines whether the first period has elapsed (step S17). The first period is a specified period starting at time Tb or time Tc in FIG. If the first period has not elapsed (NO in step S17), the control device 7 returns the process to step S15.

If the first period has elapsed (YES in step S17), the control device 7 starts the compressor 1 (step S14) and ends the process. Thereby, it is possible to prevent the rising speed from becoming less than the threshold value V1 due to a failure of the pressure sensor 6, etc., and the compressor 1 from being unable to start.

Embodiment 2.
Below, refrigeration cycle device 10A in Embodiment 2 will be explained. In the first embodiment, an example has been described in which the control device 7 starts up the compressor 1 based on the rising speed of the detected value detected by the pressure sensor 6.

In the second embodiment, an example in which the control device 7 starts the compressor 1 using the electromagnetic valve 11 disposed in the heat source side unit 100 will be described with reference to FIGS. 5 and 6. FIG. 5 is a diagram showing the configuration of a refrigeration cycle device 10A in the second embodiment. FIG. 6 is a flowchart for restarting the compressor 1 after the solenoid valve 11 disposed in the heat source side unit 100 is closed. In the second embodiment, descriptions of configurations that overlap with those in the first embodiment will not be repeated.

As shown in FIG. 5, the heat source side unit 100 included in the refrigeration cycle apparatus 10A in the second embodiment includes a solenoid valve 11. The solenoid valve 11 is arranged between the second heat exchanger 4 and the compressor 1. The electromagnetic valve 11 of the heat source side unit 100 switches the circulation path between an open state and a closed state. As described above, the electromagnetic valve 22 of the load-side unit 200 similarly switches the circulation path between the open state and the closed state.

Hereinafter, the open state of the circulation route by the solenoid valve 22 of the load side unit 200 will be referred to as a "first open state", and the closed state of the circulation route by the solenoid valve 22 of the load side unit 200 will be referred to as a "first closed state". The open state of the circulation route by the solenoid valve 11 of the heat source side unit 100 is referred to as a "second open state", and the closed state of the circulation route by the solenoid valve 11 of the heat source side unit 100 is referred to as a "second closed state".

The control device 7 is configured to be able to control the solenoid valve 11 arranged in the heat source side unit 100. Thereby, the control device 7 can control the solenoid valve 11 without using the pressure sensor 6 and prevent liquid refrigerant from flowing in when the compressor 1 is started. Referring to FIG. 6, a control flow of the control device 7 in the second embodiment will be described.

The control device 7 executes a low pressure cut (step S21). That is, the control device 7 stops the compressor 1 due to the circulation path being in the first closed state.

Subsequently, the control device 7 determines whether the compressor 1 is in a ready state (step S22). That is, the control device 7 determines whether the detected value of the pressure sensor 6 has reached the low pressure cut return value. If the detected value of the pressure sensor 6 has not reached the low pressure cut return value and the compressor 1 is not in the ready state (NO in step S22), the control device 7 stops the process at step S22.

When the detected value of the pressure sensor 6 reaches the low pressure cut return value and the compressor 1 is in the ready state (YES in step S22), the control device 7 controls the circulation path to the second closed state (step S23). ). After that, the control device 7 controls the compressor 1 from the stopped state to the activated state (step S24). Here, the compressor 1 is controlled from the stopped state to the activated state, but since the circulation path is switched to the closed state by the solenoid valve 11, the liquid refrigerant does not suddenly flow in from the suction side of the compressor 1. .

After starting the compressor 1, the control device 7 determines whether the second period has elapsed (step S25). The second period is a specified period starting from when the compressor 1 is started (step S24). If the second period has not elapsed (NO in step S25), the control device 7 stops the process at step S25. As the second period elapses, the compressor 1 completely transitions from the stopped state to the activated state to the activated state.

When the control device 7 determines that the second period has elapsed (YES in step S25), it controls to the second open state (step S26). That is, the control device 7 switches the solenoid valve 11 to put the circulation path in the second open state. As a result, refrigerant is allowed to flow into the compressor 1 after the compressor 1 has completely transitioned to the activated state, rather than during the transition period from the stopped state to the activated state.

Thereby, in the refrigeration cycle apparatus 10A, the control flow shown in FIG. 6 can prevent liquid refrigerant from suddenly flowing into the compressor 1 during the transition from the stopped state to the activated state. In this manner, also in the refrigeration cycle device 10A of the second embodiment, by using the solenoid valve 11, it is possible to prevent malfunctions in the operation of the compressor 1 due to sudden inflow of refrigerant from the suction side of the compressor 1. .

<First modification of Embodiment 2>
Below, a modification of the control flow of the control device 7 in the second embodiment will be shown. In FIG. 7, an example will be described in which the control device 7 starts the compressor 1 using the solenoid valve 22 and the solenoid valve 11. Specifically, when the control device 7 switches the circulation path from the closed state to the open state using the solenoid valve 22, if the rising speed detected by the pressure sensor 6 is not less than the threshold value V1, the solenoid valve 11 switches the compressor 1, the circulation route is switched from the second closed state to the second open state.

FIG. 7 is a flowchart of a modification example in which the compressor is restarted after the solenoid valve disposed in the heat source side unit is closed. Steps S31 to S34 in the flowchart of FIG. 7 correspond to steps S11 to S14 of the flowchart of FIG. 3, respectively. In other words, if the flowchart shown in FIG. 7 is compared with the flowchart shown in FIG. 3, the processing when the control device 7 determines that the rising speed is not less than the threshold value V1 is different. In FIG. 3, the compressor standby process is executed (step S15), whereas in FIG. 7, the control device 7 controls to the second closed state (step S35).

Furthermore, steps S35 to S38 in the flowchart in FIG. 7 correspond to steps S23 to S26 in the flowchart in FIG. 6, respectively. That is, from step S35 onward in the flowchart shown in FIG. 7, the control device 7 executes the same processing as the processing from step S23 described in FIG. 6.

In this way, by combining the pressure sensor 6 and the electromagnetic valve 11 as shown in FIG. Thus, malfunctions in the operation of the compressor 1 can be prevented. Furthermore, in the control flow shown in FIG. 7, the second closed state is controlled only when the rising speed is equal to or higher than the threshold value V1. Thereby, in FIG. 7, opening and closing of the electromagnetic valve can be reduced.

Further, in the second embodiment, a configuration in which the control device 7 is not connected to the load side unit 200 has been described, but even in a configuration in which the control device 7 and the load side unit 200 are connected, FIG. The control flow shown in 7 can be applied. In this case, since the control device 7 is connected to the load-side unit 200, it can directly determine whether or not the solenoid valve 22 has been switched.

Therefore, the control device 7 may replace the process of determining whether it is in the preparation state (step S22) in FIG. 6 with the process of determining whether it has been switched to the first open state. Similarly, the control device 7 may replace the process of determining whether it is in the preparation state (step S32) in FIG. 7 with the process of determining whether it has been switched to the first open state.

In other words, when the circulation path is switched from the first closed state to the first open state, the control device 7 switches the circulation path from the second open state to the second closed state by controlling the solenoid valve 11. You can. Thereby, the control device 7 can switch to the second closed state without determining whether or not it is in the preparation state.

(summary)
The present embodiment will be summarized below.

As shown in FIGS. 1 to 3, a refrigeration cycle device 10 according to the present disclosure includes a compressor 1, a first heat exchanger 2, a second heat exchanger 4, an expansion valve 31, a compressor 1, a first 1 heat exchanger 2, expansion valve 31, and second heat exchanger 4 in order to circulate the refrigerant; a control device 7 that controls the compressor 1; and a pressure sensor 6 that detects the pressure inside. The pressure reducing device 3 is configured to be able to switch the circulation path between an open state and a closed state. When the pressure reducing device 3 switches the circulation path from the closed state to the open state, the control device 7 controls the compressor 1 when the rate of increase in pressure specified based on the detected value of the pressure sensor 6 is less than a threshold value V1. to start.

Thereby, in the refrigeration cycle device 10, when the compressor 1 is started, refrigerant suddenly flows in from the suction side of the compressor 1, thereby preventing malfunctions in the operation of the compressor.

Preferably, as shown in FIG. 2, the pressure reducing device 3 switches the circulation path from an open state to a closed state when the temperature of the air exchanging heat with the second heat exchanger becomes less than a prescribed first temperature, When the temperature of the air exchanging heat with the second heat exchanger reaches a predetermined second temperature or higher, the circulation route is switched from the closed state to the open state. This prevents malfunctions in the operation of the compressor 1 due to sudden inflow of refrigerant from the suction side of the compressor 1 when a low pressure cut is performed.

Preferably, as shown in FIG. 3, when the pressure reducing device 3 switches the circulation route from the closed state to the open state, the compressor is stopped if the rising speed is equal to or higher than a threshold value. Thereby, it is possible to prevent refrigerant from suddenly flowing in from the suction side of the compressor 1 when the rising speed is equal to or higher than the threshold value.

Preferably, as shown in FIG. 4, if the rising speed does not fall below the threshold value V1 after the first period elapses after the solenoid valve 22 switches the circulation path from the closed state to the open state, Start compressor 1. Thereby, it is possible to prevent the rising speed from becoming less than the threshold value V1 due to a failure of the pressure sensor 6, etc., and the compressor 1 from being unable to start.

Preferably, as shown in FIG. 2, the pressure reducing device 3 includes an expansion valve 31 and a solenoid valve disposed between the first heat exchanger 2 and the expansion valve 31 to switch the circulation path between an open state and a closed state. 22.

As shown in FIG. 5 or FIG. 6, the refrigeration cycle device 10A according to the present disclosure includes a compressor 1, a first heat exchanger 2, a second heat exchanger 4, an expansion valve 31, a compressor 1, a first 1 heat exchanger 2, expansion valve 31, and second heat exchanger 4 in order, and a circulation path arranged between the first heat exchanger 2 and expansion valve 31, and a first opening of the circulation path. a solenoid valve 22 that switches the circulation path between the open state and the first closed state, and a solenoid valve 11 that is disposed between the second heat exchanger 4 and the compressor 1 and switches the circulation path between the second open state and the second closed state. , a control device 7 that controls the compressor 1 and the solenoid valve 11. When the solenoid valve 22 switches the circulation path from the first closed state to the first open state, the control device 7 starts the compressor 1 in the second closed state, and then switches the circulation path from the second closed state to the second open state. Switch to state.

As a result, in the refrigeration cycle device 10, when starting the compressor 1, the refrigerant suddenly flows in from the suction side of the compressor 1 without using the pressure sensor 6, causing a malfunction in the operation of the compressor. prevent this from happening.

Preferably, as shown in FIG. 7, the refrigeration cycle device 10A further includes a pressure sensor 6 that is disposed on the suction side of the compressor 1 and detects the pressure within the circulation path. When the solenoid valve 22 switches the circulation path from the closed state to the open state, the control device 7 switches the circulation path in the second closed state if the rate of increase in pressure specified based on the detected value of the pressure sensor 6 is not less than a threshold value. After starting the compressor 1, the circulation path is switched from the second closed state to the second open state.

As a result, by combining the pressure sensor 6 and the solenoid valve 11, the control device 7 can rapidly supply liquid refrigerant to the compressor 1 during the transition from the stop state to the start state, while reducing the opening and closing of the solenoid valve. It is possible to prevent problems from occurring in the operation of the compressor 1 due to the inflow.

Preferably, the control device 7 switches the circulation path from the second open state to the second closed state by controlling the electromagnetic valve 11 when the circulation path switches from the first closed state to the first open state.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

1 Compressor, 2 Condenser, 3 Pressure reducing device, 4 Evaporator, 6 Pressure sensor, 7 Control device, 8 Display, 10, 10A Refrigeration cycle device, 11, 22 Solenoid valve, 20 Liquid piping, 21 Gas piping, 25 Temperature Detector, 31 Expansion valve, 100 Heat source side unit, 200 Load side unit, D direction, Ta, Tb, Tc, Td, Te, Tf time, V1, V2 threshold, Ve, Vf speed.

Claims (9)

A refrigeration cycle device,
a compressor;
a first heat exchanger;
a second heat exchanger;
a pressure reducing device;
a circulation path that circulates a refrigerant in the order of the compressor, the first heat exchanger, the pressure reduction device, and the second heat exchanger;
a control device that controls the compressor;
a pressure sensor arranged on the suction side of the compressor to detect the pressure in the circulation path,
The pressure reducing device is configured to be able to switch the circulation path between an open state and a closed state,
The control device controls the compression when the rate of increase in pressure specified based on the detected value of the pressure sensor is less than a threshold value when the pressure reducing device switches the circulation route from the closed state to the open state. A refrigeration cycle device that starts the machine. The pressure reducing device is
switching the circulation route from the open state to the closed state when the temperature of the air exchanging heat with the second heat exchanger becomes less than a prescribed first temperature;
The refrigeration cycle device according to claim 1, wherein the circulation path is switched from the closed state to the open state when the temperature of the air exchanging heat with the second heat exchanger reaches a predetermined second temperature or higher. 2. The control device stops the compressor if the rate of increase is equal to or higher than the threshold when the pressure reducing device switches the circulation route from the closed state to the open state. The refrigeration cycle device described in . The control device starts the compressor if the rising speed does not decrease below the threshold value by the time a first period elapses after the pressure reducing device switches the circulation route from the closed state to the open state. The refrigeration cycle device according to any one of claims 1 to 3. The pressure reducing device includes an expansion valve and a first switching device that is arranged between the first heat exchanger and the expansion valve and switches the circulation path between the open state and the closed state. The refrigeration cycle device according to any one of claims 1 to 4. A refrigeration cycle device,
a compressor;
a first heat exchanger;
a second heat exchanger;
a pressure reducing device;
a circulation path that circulates a refrigerant in the order of the compressor, the first heat exchanger, the pressure reduction device, and the second heat exchanger;
a second switching device disposed between the second heat exchanger and the compressor and switching the circulation path between a second open state and a second closed state;
a control device that controls the compressor and the second switching device ;
a pressure sensor arranged on the suction side of the compressor to detect the pressure in the circulation path ,
The pressure reducing device is configured to be able to switch the circulation path between a first open state and a first closed state,
The control device is configured to control, when the pressure reducing device switches the circulation route from the first closed state to the first open state, if the rate of increase in pressure specified based on the detected value of the pressure sensor is not less than a threshold value. In the refrigeration cycle device, the circulation path is switched from the second closed state to the second open state after starting the compressor in the second closed state. The control device switches the circulation path from the second open state to the second open state by controlling the second switching device when the circulation path switches from the first closed state to the first open state. The refrigeration cycle device according to claim 6 , wherein the refrigeration cycle device is switched to a closed state. The pressure reducing device is
switching the circulation path from the first open state to the first closed state when the temperature of the air exchanging heat with the second heat exchanger becomes less than a prescribed first temperature;
Claim 6 or Claim 7 , wherein the circulation route is switched from the first closed state to the first open state when the temperature of the air exchanging heat with the second heat exchanger reaches a predetermined second temperature or higher. The refrigeration cycle device described in . The pressure reducing device includes an expansion valve and a first switching device that is disposed between the first heat exchanger and the expansion valve and switches the circulation path between the first open state and the first closed state. The refrigeration cycle device according to any one of claims 6 to 8 , comprising:

Images