Gas engine driven air conditioner control device

Abstract

To provide a control device capable of reducing the number of components of a gas engine driven type air conditioner (cleaning device for a gas engine driven type air conditioner).SOLUTION: A cleaning device includes: a strainer for introducing mixed fluid containing a gaseous refrigerant, a liquid refrigerant, refrigeration machine oil and foreign matters and removing the foreign matters in the mixed fluid; and a separation device storing the liquid refrigerant and the refrigeration machine oil and supplying the gaseous refrigerant to an accumulator 17. While the cleaning device is provided in an intermediate part of a refrigerant pipe, a control device 100 starts driving of a gas engine, and has at least one function of a first determination function for determining whether or not the amount of the foreign matters stored in the strainer reaches an upper limit value on the basis of a detection result of pressure of the gaseous refrigerant obtained by a pressure sensor and a second function for determining whether or not the amount of the liquid fluid stored in the separation device reaches an upper limit value on the basis of a detection result of a temperature of the gaseous refrigerant obtained by a temperature sensor.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a control device for a gas engine-driven air conditioner that has a function of cleaning refrigerant pipes (removing refrigeration oil and foreign matter). [Background technology]

[0002] For example, as described in Patent Document 1 below, there is known an air conditioner (refrigeration cycle device (hereinafter referred to as "conventional device")) that adjusts the temperature of indoor air by circulating a refrigerant through an outdoor unit and an indoor unit. When the outdoor unit of the conventional device breaks down, the indoor unit and refrigerant pipe continue to be used, and only the outdoor unit is replaced. At that time, refrigeration oil remaining in the refrigerant pipe (refrigeration oil for the outdoor unit before replacement) is removed using a cleaning device (a device that stores refrigeration oil). The cleaning device is connected to an intermediate portion of the refrigerant pipe for returning the refrigerant from the indoor unit to the outdoor unit. The control device of the conventional device drives a compressor (gas engine) to circulate the refrigerant between the outdoor unit and the indoor unit. Refrigeration oil is introduced into the cleaning device together with the refrigerant.

[0003] The cleaning device has a tank for storing refrigeration oil. The cleaning device separates the refrigerant and the refrigeration oil, stores only the refrigeration oil in the tank, and sends the refrigerant to the compressor. The conventional device further includes an oil level sensor for detecting the amount of refrigeration oil in the tank. The control device of the conventional device monitors the detection results of the oil level sensor. When the control device detects that the amount of refrigeration oil in the tank has reached its upper limit, it temporarily stops the operation of the compressor (gas engine). In this case, the worker drains the refrigeration oil in the tank from the tank and then resumes the cleaning work. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-24505 A Summary of the Invention

[0005] In the above-mentioned conventional device, the oil level sensor is relatively expensive, and the parts cost of the gas engine-driven air conditioner (cleaning device) is high.

[0006] The present invention aims to provide a control device that can reduce the number of parts in a gas engine-driven air conditioning system (a cleaning device for a gas engine-driven air conditioning system). In the description of each component of the present invention below, the reference numerals of corresponding parts in the embodiment are written in parentheses to facilitate understanding of the present invention, but each component of the present invention should not be interpreted as being limited to the configuration of the corresponding parts indicated by the reference numerals in the embodiment.

[0007] In order to achieve the above object, a control device (100) according to the present invention comprises: a compressor (11) that compresses a gaseous refrigerant; A gas engine that drives the compressor; an accumulator (17) that separates a liquid refrigerant from a gaseous refrigerant, stores the liquid refrigerant, and supplies the gaseous refrigerant to the compressor; a pressure sensor (41) and a temperature sensor (42) for detecting the pressure and temperature, respectively, of a gaseous refrigerant introduced into the compressor; This applies to a gas engine-driven air conditioner (1) equipped with a The control device includes a strainer that introduces a mixed fluid containing a gaseous refrigerant, a liquid refrigerant, a refrigeration oil, and foreign matter and removes the foreign matter from the mixed fluid; A tank having a predetermined capacity, which stores liquid refrigerant and refrigeration oil among the fluids discharged from the strainer, and when the stored amount of the liquid refrigerant and the refrigeration oil is equal to or less than the capacity, Only the gaseous refrigerant is supplied to the accumulator, A tank configured such that, when the amount of the liquid refrigerant and the refrigeration oil stored exceeds the capacity, the stored liquid refrigerant is supplied to the accumulator in addition to the gaseous refrigerant. A cleaning device comprising: Between the output port of the compressor and the accumulator The state of being set and a function for preventing the pressure of the gaseous refrigerant introduced into the compressor from becoming equal to or lower than a predetermined value is disabled. The gas engine is started, and the pressure of the gaseous refrigerant detected by the pressure sensor a first function for determining that the amount of foreign matter accumulated in the strainer has reached an upper limit and stopping the compressor when the amount of foreign matter increases and reaches a threshold value; and the temperature of the gaseous refrigerant by the temperature sensor. a second function of determining that the amount of liquid refrigerant and refrigeration oil stored in the tank has exceeded the capacity and stopping the compressor when the amount of liquid refrigerant and refrigeration oil stored in the tank has exceeded the capacity and reaches a threshold value. It has.

[0008] If the amount of foreign matter inside the strainer increases during the cleaning operation, it becomes difficult for the gaseous refrigerant to pass through the strainer. As a result, the pressure of the refrigerant introduced into the input port of the compressor decreases. Therefore, when the control device of the present invention detects, based on the detection result of the pressure sensor, that the pressure of the refrigerant (hereinafter referred to as "suction gas") on the input port side of the compressor has fallen below a predetermined value, it determines that the amount of foreign matter inside the strainer has reached an upper limit (the foreign matter removal (filtering) function has decreased), and stops the operation of the gas engine.

[0009] In addition, before the amount of liquid fluid (refrigerating machine oil and liquid refrigerant) stored in the separation device reaches the upper limit of the separation device, only gaseous refrigerant is sent to the accumulator. That is, in this state, the amount of liquid refrigerant does not increase in the accumulator. On the other hand, when the amount of refrigerating machine oil and liquid refrigerant in the separation device reaches the upper limit, the fluid (fluid including gaseous refrigerant and liquid refrigerant (and refrigerating machine oil)) introduced into the separation device is sent directly to the accumulator. When this fluid is introduced into the accumulator, it is centrifuged by the accumulator into gaseous refrigerant and other components. Then, the gaseous refrigerant is sent to the compressor, and the other components are stored in the accumulator. That is, the liquid refrigerant is stored in the accumulator. Then, when the amount of liquid refrigerant in the accumulator increases, a small amount of liquid refrigerant flows into the refrigerant pipe for supplying gaseous refrigerant to the compressor, and is mixed with the gaseous refrigerant. This causes the temperature of the gaseous refrigerant to decrease. That is, the temperature value detected by the temperature sensor starts to decrease. Therefore, when the control device of the present invention detects that the temperature of the refrigerant sucked into the compressor becomes lower than a predetermined value, it determines that the amount of the mixed fluid stored in the separation device has reached the upper limit value (the mixed fluid has overflowed from the separation device), and stops the operation of the gas engine.

[0010] As described above, in the present invention, it is determined whether the amount of foreign matter deposited in the cleaning device has reached an upper limit based on the pressure value of the intake gas. Also, in the present invention, it is determined whether the amount of liquid fluid stored in the separation device has reached an upper limit based on the temperature value of the intake gas. Here, the pressure sensor and temperature sensor are provided mainly to detect the pressure and temperature of the intake gas during normal operation (cooling operation or heating operation). In the present invention, the gas engine is controlled based on the detection results of one or both of these sensors during the cleaning operation. That is, according to the present invention, the number of parts of the gas engine-driven air conditioner (cleaning device) can be reduced compared to when a dedicated sensor for detecting the amount of foreign matter deposited in the strainer is provided in the cleaning device. Also, the number of parts of the air conditioner (cleaning device) can be reduced compared to when a dedicated sensor for detecting the amount of refrigeration oil stored in the separation device is provided in the cleaning device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a circuit diagram showing a schematic configuration of an air conditioning apparatus according to one embodiment and a second embodiment of the present invention. [Diagram 2] FIG. 4 is a cross-sectional view showing the structure of an accumulator. [Diagram 3] 13 is a flowchart of a cleaning program. [Figure 4] 1 is a flowchart of a first program. [Diagram 5] 11 is a flowchart of a second program. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a gas engine-driven air conditioner 1 (hereinafter, simply referred to as "air conditioner 1") to which a control device 100 according to one embodiment of the present invention is applied will be described. As shown in FIG. 1, the air conditioner 1 includes an outdoor unit 10 and an indoor unit 20. Furthermore, the air conditioner 1 includes a refrigerant pipe 30 as a refrigerant circulation path between the outdoor unit 10 and the indoor unit 20. That is, each component of the outdoor unit 10 and the indoor unit 20 is connected by a plurality of pipes (such as a refrigerant pipe 31, a refrigerant pipe 32, and a hot gas bypass pipe 33, which will be described later) that constitute the refrigerant pipe 30. In addition, the air conditioner 1 includes a control device 100 that controls the outdoor unit 10 and the indoor unit 20. The control device 100 controls each device that constitutes the outdoor unit 10 and the indoor unit 20. The structures and functions of the various devices that constitute the outdoor unit 10 and the indoor unit 20 are substantially the same as the structures and functions of the various devices that constitute the outdoor unit and the indoor unit of a known air conditioner. Therefore, the components of the outdoor unit 10 and the indoor unit 20 will be outlined below.

[0013] The outdoor unit 10 includes a compressor 11, an oil separator 12, a four-way switching valve 13, an outdoor heat exchanger 14, a flow control valve 15, a receiver 16, and an accumulator 17. The compressor 11 is connected to a gas engine (not shown) and is driven by the gas engine. The sliding parts of the compressor 11 are lubricated with refrigeration oil. The compressor 11 has an input port and an output port. The compressor 11 draws in low-pressure gaseous refrigerant from the input port, compresses the drawn refrigerant, and discharges it from the output port. The oil separator 12 separates and stores the refrigeration oil contained in the refrigerant discharged from the compressor 11.

[0014] The four-way switching valve 13 has four ports P1 to P4. The four-way switching valve 13 is switchable between a first state in which the port P1 communicates with the port P4 and the port P2 communicates with the port P3, and a second state in which the port P1 communicates with the port P2 and the port P3 communicates with the port P4.

[0015] The outdoor heat exchanger 14 includes a plurality of pipes with heat dissipation fins. The outdoor heat exchanger 14 includes two ports. The refrigerant introduced into one port passes through the plurality of pipes and is discharged from the other port.

[0016] The outdoor heat exchanger 14 includes a fan (blower) (not shown). The fan blows outdoor air onto the heat dissipation fins of the outdoor heat exchanger 14. This causes heat exchange between the refrigerant flowing through the outdoor heat exchanger 14 and the outdoor air.

[0017] The flow rate adjustment valve 15 adjusts the flow rate of the refrigerant flowing through the refrigerant pipe 30. The receiver 16 temporarily stores the liquefied refrigerant.

[0018] The accumulator 17 separates the mixed refrigerant, which is a mixture of gaseous refrigerant and liquid refrigerant, into the gaseous refrigerant and the liquid refrigerant, stores the liquid refrigerant, and returns only the gaseous refrigerant to the compressor 11. As shown in FIG. 2, the accumulator 17 includes a container 171 and a U-shaped pipe 172. The container 171 has a cylindrical shape extending in the vertical direction. An input port and an output port of the refrigerant are provided in an upper lid portion 171a. The pipe 172 is accommodated in the container 171. Straight portions 172a and 172b of the pipe 172 are arranged so as to coincide with the vertical direction, and a curved portion 172c is directed toward the bottom side of the container 171. The upper end of the straight portion 172a is located below the upper lid portion 171a of the container 171 and is open inside the container 171. On the other hand, the upper end of the straight portion 172b is connected to the output port. A small hole TH is provided on the side surface of the curved portion 172c.

[0019] 1 again, the indoor unit 20 includes an indoor heat exchanger 21 and an expansion valve 22. The configuration of the indoor heat exchanger 21 is substantially the same as the configuration of the outdoor heat exchanger 14. When the refrigerant flows through the indoor heat exchanger 21, heat exchange occurs between the refrigerant and the indoor air. The expansion valve 22 reduces the pressure of the refrigerant.

[0020] The components of the air conditioner 1 described above are connected as follows: An output port of the compressor 11 and a port P1 of the four-way switching valve 13 are connected via an oil separator 12. A port P4 of the four-way switching valve 13 and one port of the outdoor heat exchanger 14 are connected. A port P3 of the four-way switching valve 13 and an input port of the accumulator 17 are connected. In addition, an output port of the accumulator 17 and an input port of the compressor 11 are connected.

[0021] Furthermore, the other port of the outdoor heat exchanger 14 (the side opposite to the port connected to the four-way switching valve 13) is connected to the flow rate control valve 15. The flow rate control valve 15 and the expansion valve 22 are connected via a receiver 16. The pipe connecting the receiver 16 and the expansion valve 22 is referred to as the "refrigerant pipe 31." Furthermore, one port of the indoor heat exchanger 21 is connected to the expansion valve 22. Furthermore, the other port of the indoor heat exchanger 21 is connected to port P2 of the four-way switching valve 13. The pipe connecting the other port of the indoor heat exchanger 21 and port P2 of the four-way switching valve 13 is referred to as the "refrigerant pipe 32."

[0022] In addition, the outdoor heat exchanger 14 and the indoor heat exchanger 21 are bypassed by a hot gas bypass pipe 33. Specifically, one end of the hot gas bypass pipe 33 is inserted into the accumulator 17 from a lower part of the side part thereof (see FIG. 2). Meanwhile, the other end of the hot gas bypass pipe 33 is connected to a midpoint (branch point 30a) between the four-way switching valve 13 and the oil separator 12 (see FIG. 1). A hot gas bypass on-off valve 33a is provided in the hot gas bypass pipe 33.

[0023] The air conditioner 1 also includes sensors 40 that detect the temperature, pressure, and the like of various components. The sensors 40 include a pressure sensor 41 and a temperature sensor 42 that detect the pressure and temperature, respectively, of the refrigerant near the output port of the accumulator 17, for example.

[0024] The control device 100 includes a microcomputer including an arithmetic unit, a memory, a timer, etc. The control device 100 includes an operation panel equipped with switches, a display device, etc. that are used when a user sets the air conditioning mode (cooling mode or heating mode), the target room temperature, air volume, etc. These setting information are input to the microcomputer of the control device 100. The control device 100 controls the outdoor unit 10 (e.g., the rotation speed of a gas engine) and the indoor unit 20 based on the above setting information, temperature information and pressure information acquired from various sensors, etc., so that the room temperature and air volume match the target values.

[0025] In the cooling mode, the switching state of the four-way switching valve 13 is set to the first state. In this case, the refrigerant circulates as follows. High-pressure gaseous refrigerant discharged from the compressor 11 is introduced into the oil separator 12.

[0026] The refrigerant discharged from the oil separator 12 is introduced into the outdoor heat exchanger 14 via the four-way switching valve 13. The high-pressure gaseous refrigerant introduced into the outdoor heat exchanger 14 releases heat to the outside air while flowing through the outdoor heat exchanger 14, and is condensed.

[0027] The refrigerant that has released heat to the outside air and condensed is partially liquefied and discharged from the outdoor heat exchanger 14. It is then expanded in the expansion valve 22 to reduce its pressure and is introduced into the indoor heat exchanger 21 of the indoor unit 20. The refrigerant introduced into the indoor heat exchanger 21 absorbs heat from the indoor air while flowing through the indoor heat exchanger 21 and partially evaporates. At this time, the refrigerant absorbs heat from the indoor air, thereby cooling the indoor air.

[0028] The refrigerant that has absorbed heat from the indoor air and partially evaporated is discharged from the indoor heat exchanger 21 and introduced into the accumulator 17. The refrigerant discharged from the indoor heat exchanger 21 is the mixed refrigerant described above. This mixed refrigerant flows through the refrigerant pipe 31 and reaches the accumulator 17. When the mixed refrigerant is introduced into the accumulator 17, the mixed refrigerant forms a swirling flow that swirls along the inner surface of the side wall of the accumulator 17. In this way, in the accumulator 17, the mixed refrigerant is centrifuged into a gaseous refrigerant and a liquid refrigerant, and only the gaseous refrigerant is sucked into the compressor 11. Meanwhile, the separated liquid refrigerant is stored at the bottom of the accumulator 17.

[0029] On the other hand, in the heating mode, the switching state of the four-way switching valve 13 is set to the second state. In this case, the refrigerant circulates as follows. The high-pressure gaseous refrigerant discharged from the compressor 11 is introduced into the oil separator 12.

[0030] The refrigerant discharged from the oil separator 12 is introduced into the indoor heat exchanger 21. The high-pressure gaseous refrigerant introduced into the indoor heat exchanger 21 releases heat to the indoor air and condenses while flowing through the indoor heat exchanger 21. At this time, the indoor air is warmed by the heat released from the refrigerant. The refrigerant that has released heat to the indoor air and condensed is discharged from the indoor heat exchanger 21.

[0031] The refrigerant is then introduced into the outdoor heat exchanger 14 via the receiver 16. While circulating through the outdoor heat exchanger 14, the refrigerant absorbs heat from the outside air and evaporates, and is discharged from the outdoor heat exchanger 14. The refrigerant (mixed refrigerant) discharged from the outdoor heat exchanger 14 is introduced into the accumulator 17 via the four-way switching valve 13. As in the cooling operation, the mixed refrigerant is separated into gaseous refrigerant and liquid refrigerant in the accumulator 17. Then, only the gaseous refrigerant is sucked into the compressor 11, and the liquid refrigerant is stored in the accumulator 17.

[0032] Here, there are cases where the pressure of the refrigerant on the input port side of the compressor 11 (hereinafter referred to as "suction gas") falls below a predetermined lower limit. The air conditioner 1 has a function for avoiding an excessive drop in the pressure value of the suction gas as described above.

[0033] Specifically, when the control device 100 detects that the detection result PL (intake gas pressure value) of the pressure sensor 41 falls below the lower limit, the control device 100 increases the rotation speed of the gas engine. This keeps the intake gas pressure value higher than the lower limit. Hereinafter, this function is referred to as a first low pressure avoidance function.

[0034] Furthermore, when the control device 100 detects that the detection result PL (suction gas pressure value) of the pressure sensor 41 falls below the lower limit, it opens the hot gas bypass on-off valve 33a. As a result, a part of the high-temperature, high-pressure gaseous refrigerant (hot gas) discharged from the compressor 11 passes through the hot gas bypass pipe 33 and is introduced into the accumulator 17. This heats the refrigerant in the accumulator 17, and the pressure value of the suction gas is maintained at a value higher than the lower limit. Hereinafter, this function is referred to as a second low pressure avoidance function.

[0035] Incidentally, when the outdoor unit 10 breaks down and is replaced with a new outdoor unit 10, a cleaning device 50 for removing refrigeration oil and foreign matter remaining in the refrigerant pipe 30 is attached to the middle of the refrigerant pipe 32. The cleaning device 50 includes a tank 51, shutoff valves 52, 53, 54, a strainer 55, and a discharge valve 56. The tank 51 is a box-shaped member, and an input port 511a and an output port 511b are provided on an upper cover portion 511 of the tank 51. The shutoff valve 52 is provided in the middle of the refrigerant pipe 32. Parts of the refrigerant pipe 32 located on both sides of the shutoff valve 52 are connected to the input port 511a and the output port 511b of the tank 51 via the bypass pipes 34 and 35, respectively. The shutoff valve 53 and the shutoff valve 54 are provided in the middle of the bypass pipes 34 and 35. The strainer 55 is provided between the tank 51 and the shutoff valve 53. That is, an input port 551 of the strainer 55 is connected to the stop valve 53 via the bypass pipe 34. On the other hand, an output port 552 of the strainer 55 is connected to an input port 511a of the tank 51.

[0036] The discharge valve 56 is connected to the bottom of the tank 51 via the discharge pipe 36. By opening the discharge valve 56, the refrigeration oil stored in the tank 51 can be discharged to the outside of the tank 51.

[0037] Next, the procedure of the work to remove the refrigeration oil and foreign matter remaining in the refrigerant pipe 30 (hereinafter referred to as the "cleaning work") will be described. First, the worker closes the shutoff valve 52 and opens the shutoff valves 53 and 54. Next, the worker sets the operation mode of the air conditioner 1 to a predetermined cleaning mode. Then, the control device 100 starts controlling the compressor 11 and various valves in a mode substantially the same as the cooling mode, and circulates the refrigerant between the outdoor unit 10 and the indoor unit 20. Here, in the cleaning mode, the control device 100 stops the first low pressure avoidance function and the second low pressure avoidance function. In the process of circulating the refrigerant, the mixed refrigerant discharged from the indoor unit 20 contains the refrigeration oil and foreign matter. Hereinafter, this mixed refrigerant will be referred to as the "mixed fluid". This mixed fluid is introduced into the tank 51 through the strainer 55. At that time, foreign matter (solid matter) contained in the mixed fluid is captured (filtered) by the strainer 55.

[0038] The fluid introduced into the tank 51 (fluid from which foreign matter has been removed) is centrifuged in the tank 51, and the liquid refrigerant and refrigeration oil are stored in the tank 51, and the gaseous refrigerant is sent from the output port 511b to the accumulator 17. The refrigeration oil accumulates on the bottom side of the tank 51, and the liquid refrigerant accumulates above it.

[0039] When a predetermined time has elapsed since the start of the cleaning operation (when the cleaning operation is completed), the control device 100 stops the operation of the gas engine. In this state, the worker closes the stop valves 53 and 54, and opens the stop valve 52. Then, the worker removes the tank 51 from the bypass pipes 34 and 35.

[0040] If the amount of foreign matter in the strainer 55 increases during the cleaning operation, it becomes difficult for the mixed fluid to flow through the strainer 55, and the pressure of the refrigerant introduced into the input port of the compressor 11 decreases. When the control device 100 detects that the refrigerant pressure is lower than a predetermined value based on the detection result of the pressure sensor 41, it determines that "the amount of foreign matter in the strainer 55 has reached an upper limit (the filtering function of the strainer 55 for filtering foreign matter has decreased)," and stops the operation of the gas engine. In this case, the worker replaces the strainer 55 and then resumes the cleaning operation.

[0041] Further, before the amount of the refrigerating machine oil and liquid refrigerant stored in the tank 51 reaches the upper limit, only the gaseous refrigerant is sent from the tank 51 to the accumulator 17. That is, in this state, the liquid refrigerant does not increase in the container 171 of the accumulator 17. On the other hand, when the amount of the refrigerating machine oil and liquid refrigerant in the tank 51 increases and reaches the upper limit, the liquid refrigerant (and the refrigerating machine oil) is sent from the tank 51 to the accumulator 17 together with the gaseous refrigerant. That is, the liquid refrigerant (and the refrigerating machine oil) overflows from the tank 51. When this liquid refrigerant (and the refrigerating machine oil) is introduced into the accumulator 17, the accumulator 17 separates the liquid refrigerant into the gaseous refrigerant and other components. Then, the gaseous refrigerant is sent from the open end of the straight portion 172a of the pipe 172 to the compressor 11, and the other components are stored in the container 171. That is, the liquid refrigerant (and the refrigerating machine oil) is stored in the container 171. Then, when the liquid level reaches the position of the small hole TH provided in the pipe 172, a small amount of liquid refrigerant enters the pipe 172 from the small hole TH. Therefore, the gaseous refrigerant introduced into the pipe 172 from the upper end (open end) of the straight part 172a and the liquid refrigerant introduced into the pipe 172 from the small hole TH are mixed. This causes the temperature of the intake gas to decrease. That is, the temperature value output from the temperature sensor 42 decreases. When the control device 100 detects that the difference between the temperature of the refrigerant sucked into the compressor 11 and the low pressure equivalent temperature becomes smaller than a predetermined value, it determines that "the amount of the refrigerating machine oil and the liquid refrigerant stored in the tank 51 has reached the upper limit value" and stops the operation of the gas engine. In this case, the operator drains the refrigerating machine oil stored in the tank 51 and then resumes the cleaning work.

[0042] The operation of the control device 100 in the above-mentioned cleaning operation will be specifically described with reference to FIG. 3. When the operation mode of the air conditioner 1 is set to the cleaning mode, the control device 100 starts the cleaning process from step 300. Next, the control device 100 stops the low pressure avoidance function (first low pressure avoidance function and second low pressure avoidance function) in step 301. Next, the control device 100 sets the operation mode of various valves to the same mode as the operation mode in the cooling mode and starts driving the gas engine in step 302. Next, the control device 100 starts measuring the elapsed time Δt using a timer in step 303. Next, the control device 100 determines whether the elapsed time Δt has reached a predetermined time tth (for example, "15 minutes") in step 304. When the elapsed time Δt has reached the predetermined time tth (step 304: Yes), the control device 100 stops the driving of the gas engine in step 305 and ends the cleaning process in step 306.

[0043] On the other hand, in step 304, when the elapsed time Δt has not yet reached the predetermined time tth (step 304: No), the control device 100 in step 307 determines whether or not the following condition A is satisfied. (Condition A) The detection result PL of the pressure sensor 41 is equal to or less than a predetermined value PLth (for example, "0.28 MPa").

[0044] If condition A is met (step 307: Yes), in step 308, the control device 100 presents the operator with information (text, graphics, voice, etc.) indicating that the amount of foreign matter accumulated in the strainer 55 has reached its upper limit, and then proceeds to step 305.

[0045] On the other hand, if condition A is not satisfied in step 307 (step 307: No), the control device 100 determines in step 309 whether or not the following condition B is satisfied. (Condition B) The difference between the detection result T of the temperature sensor 42 and the low pressure equivalent temperature TL is equal to or lower than a predetermined temperature Tth (e.g., "3°C") for more than a predetermined time tL (e.g., "5 minutes").

[0046] If condition B is satisfied (step 309: Yes), in step 310, the control device 100 presents information (text, graphics, voice, etc.) to the operator indicating that the amount of refrigeration oil and liquid refrigerant stored in the tank 51 has exceeded its upper limit, and then proceeds to step 305.

[0047] On the other hand, if the condition B is not satisfied (step 309: No), the control device 100 returns to step 304.

[0048] In the above embodiment, it is determined whether the amount of accumulated foreign matter in the strainer 55 has reached an upper limit based on the detection result PL of the pressure sensor 41. Therefore, compared to when a dedicated sensor for detecting the amount of accumulated foreign matter in the strainer 55 is provided in the cleaning device 50, the number of parts of the air conditioning device 1 (cleaning device 50) can be reduced. Also, in the above embodiment, it is determined whether the amount of refrigeration oil and liquid refrigerant stored in the tank 51 has reached an upper limit based on the difference between the detection result T of the temperature sensor 42 and the low pressure equivalent temperature TL and the duration of that state. Therefore, it is possible to reduce the number of parts of the air conditioning device 1 (cleaning device 50) compared to when a dedicated sensor for detecting the amount of refrigeration oil stored in the tank 51 is provided in the cleaning device 50.

[0049] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the object of the present invention.

[0050] For example, the cleaning program shown in Fig. 3 may be divided into a first program (a program for determining whether the amount of accumulated foreign matter in strainer 55 has reached an upper limit) and a second program (a program for determining whether the amount of fluid stored in tank 51 has reached an upper limit) as shown in Fig. 4 and Fig. 5, respectively, and these two programs may be executed simultaneously or alternately. Also, only one of the first program and the second program may be executed. [Explanation of symbols]

[0051] 1...gas engine driven air conditioner, 10...outdoor unit, 11...compressor, 17...accumulator, 20...indoor unit, 30...refrigerant pipe, 33...hot gas bypass pipe, 41...pressure sensor, 42...temperature sensor, 50...cleaning device, 51...tank, 55...strainer, 100...control device

Claims

[Claim 1] A compressor that compresses a gaseous refrigerant; A gas engine that drives the compressor; an accumulator that separates a liquid refrigerant and a gaseous refrigerant, stores the liquid refrigerant, and supplies the gaseous refrigerant to the compressor; a pressure sensor and a temperature sensor for detecting the pressure and temperature, respectively, of the gaseous refrigerant introduced into the compressor; A control device applied to a gas engine-driven air conditioning device comprising: a strainer for introducing a mixed fluid containing a gaseous refrigerant, a liquid refrigerant, a refrigeration oil, and foreign matter and removing the foreign matter from the mixed fluid; and a tank having a predetermined capacity, for storing the liquid refrigerant and the refrigeration oil from the fluid discharged from the strainer, and configured such that when the stored amounts of the liquid refrigerant and the refrigeration oil are equal to or less than the capacity, only the gaseous refrigerant is supplied to the accumulator, and when the stored amounts of the liquid refrigerant and the refrigeration oil exceed the capacity, the stored liquid refrigerant is supplied to the accumulator in addition to the gaseous refrigerant, the tank is connected to an output port of the compressor and the accumulator. and a state in which a function for preventing the pressure of the gaseous refrigerant introduced into the compressor from dropping below a predetermined value is disabled, the control device has a first function of starting operation of the gas engine, and when the pressure of the gaseous refrigerant detected by the pressure sensor increases and reaches a threshold value, determining that the amount of foreign matter stored in the strainer has reached an upper limit value and stopping the compressor, and a second function of determining that the amount of liquid refrigerant and refrigeration oil stored in the tank has exceeded the capacity and stopping the compressor when the temperature of the gaseous refrigerant detected by the temperature sensor drops and reaches a threshold value.

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