JP2012145251A - Heat pump device - Google Patents

Abstract

There is provided a heat pump device capable of appropriately setting a circulation amount of lubricating oil in accordance with a pipe length of a refrigerant pipe constituting a refrigeration cycle.
In an air conditioner 100 including a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an indoor heat exchanger 5, an expansion valve 6, and an oil separator 7, an electromagnetic wave is formed on the bottom surface of the oil separator 7. The oil return pipe 21a provided with the valve 14a is connected, the oil return pipe 21b provided with the electromagnetic valve 14b is connected to the side surface portion of the oil separator 7, and the control device 15 opens the solenoid valve 14a when the pipe is long. Then, the solenoid valve 14b is closed, and the solenoid valve 14a is closed and the solenoid valve 14b is opened during short piping.
[Selection] Figure 1

Description

  The present invention relates to a heat pump apparatus including an oil separator that separates refrigerant circulating in a refrigeration cycle and refrigeration oil.

  In a heat pump apparatus such as an air conditioner, lubricating oil (refrigerating machine oil) for lubricating the drive of a compressor that compresses a refrigerant is enclosed. A part of this lubricating oil flows into the refrigeration cycle together with the refrigerant discharged from the compressor, and the lubricating oil that has flowed out circulates in the refrigeration cycle together with the refrigerant and returns to the compressor. In such a heat pump device, an oil return pipe is connected with a space above and below the oil separator, and an electromagnetic valve is provided in the lower oil return pipe. Normally, the solenoid valve is closed to close the oil separator. A technique has been proposed in which lubricating oil is stored on the bottom side and a solenoid valve is opened to compensate for the shortage of lubricating oil when the lubricating oil in the compressor is insufficient (see Patent Document 1).

JP 2004-205175 A

  By the way, there are various lengths of refrigerant pipes constituting the refrigeration cycle. Normally, the amount of the lubricating oil filled is the largest pipe regardless of the refrigerant pipe length during construction so that the amount of lubricating oil does not become insufficient in the refrigeration cycle. Encloses a large amount of lubricating oil that is assumed to be long. This maximum pipe length is the length of one-way pipe from the outdoor unit to the indoor unit connected by the longest pipe when multiple indoor units are connected to the outdoor unit. The length of the pipe. However, the technique described in Patent Document 1 has a problem that surplus lubricating oil circulates in the refrigeration cycle when the pipe length of the refrigerant pipe is short. As a result, a large amount of lubricating oil circulates in the refrigeration cycle, and the lubricating oil stays in the refrigerant piping, heat exchanger, etc.For example, an oil film is formed in the heat transfer tube of the heat exchanger, and the heat transfer performance in the heat exchanger As a result, the cooling capacity and the heating capacity will decrease.

  This invention solves the said conventional problem, and makes it a subject to provide the heat pump apparatus which can set the circulation amount of lubricating oil appropriately according to the piping length of the refrigerant | coolant piping which comprises a refrigerating cycle. .

  The present invention relates to a compressor that compresses refrigerant, an oil separator that is provided on the discharge side of the compressor and separates lubricating oil from the compressed refrigerant, a four-way valve that switches a refrigerant flow path, and outdoor heat exchange In a heat pump device comprising: an outdoor unit comprising a vessel; an indoor unit comprising an indoor heat exchanger; and an expansion valve provided in at least one of the outdoor unit and the indoor unit; connected to a lower portion of the oil separator; A first oil return pipe connected to a low pressure pipe on the suction side of the compressor; a second oil return pipe connected to an upper part of the oil separator and connected to a low pressure pipe on the suction side of the compressor; A first cutoff valve provided in the first oil return pipe; a second cutoff valve provided in the second oil return pipe; and the first cutoff valve and the second cutoff valve based on a length of a refrigerant pipe. A control device to control opening and closing Characterized in that it comprises a.

  ADVANTAGE OF THE INVENTION According to this invention, the heat pump apparatus which can set appropriately the circulation amount of lubricating oil according to the length of the refrigerant | coolant piping which comprises a refrigerating cycle can be provided.

It is a whole lineblock diagram showing the air harmony machine concerning this embodiment. It is a block diagram which shows an oil separator and its periphery. It is a whole block diagram which shows the flow of the refrigerant | coolant at the time of air_conditionaing | cooling operation. It is a whole block diagram which shows the flow of the refrigerant | coolant at the time of heating operation. It is a control flowchart in the air conditioner concerning this embodiment. It is a block diagram which shows the oil separator of other embodiment, and its periphery.

Hereinafter, the air conditioner 100 of this embodiment is demonstrated with reference to FIG. 1 thru | or FIG.
As shown in FIG. 1, the air conditioner 100 of this embodiment is an example of a heat pump device, and includes a compressor 1, 1, a four-way valve 2, an outdoor heat exchanger 3, an oil separator 7, and a control device 15. The outdoor unit A is configured to include indoor units B1 and B2 including an indoor heat exchanger 5 and an expansion valve 6. In the following description, a case where a so-called twin type air conditioner (with two indoor units B1 and B2 for one outdoor unit A) is applied will be described as an example. The number of indoor units is not limited to two, but may be three or more, or may be one. The number (or total capacity) of the indoor units is preferably set to the number (or total capacity) at which the indoor units B1 and B2 can be operated by the operation of the outdoor unit A.

  The compressor 1 is composed of, for example, a scroll type variable capacity type (rotational speed variable type using an inverter), and compresses a low-temperature and low-pressure refrigerant from the suction side into a high-temperature and high-pressure refrigerant (gas refrigerant). , The pipe 23a, the oil separator 7, and the pipe 23b are sent to the four-way valve 2. In the present embodiment, the air conditioner 100 including two compressors 1 in parallel is described as an example. However, an air conditioner including only one compressor 1 may be used. An air conditioner including three or more compressors 1 in parallel may be used. Further, the compressor 1 is not limited to the scroll type, and is a type in which refrigerating machine oil (lubricating oil for driving the compressor 1 for lubrication) flows out of the compressor 1 together with the refrigerant, such as a rotary type and a reciprocating type. If it is a thing, it is applicable to various things.

  The four-way valve 2 is connected to the compressor 1 via a high-pressure pipe 23 (pipe 23a and pipe 23b), and is controlled by the control device 15 during cooling operation (see FIG. 3) and during heating operation (see FIG. 4). The flow can be switched. That is, in the four-way valve 2, the discharge side of the compressor 1 is connected to the outdoor heat exchanger 3 side during the cooling operation, and the suction side (low pressure pipe 22 side) of the compressor 1 is connected to the gas blocking valve via the four-way valve 2 during the heating operation. The flow path is switched to connect to the 12 side. The four-way valve 2 is connected to the outdoor heat exchanger 3 via a pipe 26, connected to the gas blocking valve 12 via a pipe 27, and further via a low-pressure pipe 22 (pipe 22a, accumulator 8 and pipe 22b). Connected to the compressor 1.

  The outdoor heat exchanger 3 functions as a condenser during the cooling operation and functions as an evaporator during the heating operation, and the end opposite to the side to which the pipe 26 is connected is liquid via the liquid pipe 25. A stop valve 13 is connected. In addition, the liquid pipe 25 is branched and formed in the middle so that it may be connected with each outdoor heat exchanger 3 and 3. The outdoor heat exchanger 3 is provided with a blower (not shown), and is configured to exchange heat between the outdoor air sent by the blower and the refrigerant flowing through the outdoor heat exchanger 3.

  The gas blocking valve 12 and the liquid blocking valve 13 can be closed to seal the refrigerant and refrigeration oil in the refrigeration cycle to the outdoor unit A, and are closed when the air conditioner 100 is installed. It is a valve that opens after completion of construction.

  In this embodiment, the case where two sets of units having the outdoor heat exchanger 3 are provided is described as an example. However, the present invention is not limited to this and may be one set. It may be a set or more. Moreover, you may enable it to select the outdoor heat exchanger 3 through which a refrigerant | coolant flows through a three-way valve so that a refrigerant | coolant may flow into one outdoor heat exchanger 3. FIG. Or you may provide the flow regulating valve which can adjust the quantity of the refrigerant | coolant which flows into each outdoor heat exchanger 3. FIG.

  The indoor heat exchanger 5 functions as an evaporator during cooling operation and functions as a condenser during heating operation. The indoor heat exchanger 5 is configured such that one end is connected to the pipe 28 a, the other end is connected to the pipe 28 b, and the outdoor unit A is connected via the unit connection pipe 16. The indoor heat exchanger 5 is provided with a blower (not shown) and is configured to exchange heat between indoor air sent by the blower and refrigerant flowing through the indoor heat exchanger 5.

  The unit connection pipe 16 includes pipes 16a, 16b, 16b, 16c, 16c, and 16d, a gas side distributor 16s, and a liquid side distributor 16t. The pipe 28a is connected to the gas blocking valve 12 via the pipe 16b, the gas side distributor 16s and the pipe 16a, and the pipe 28b is connected to the liquid blocking valve 13 via the pipe 16c, the liquid side distributor 16t and the pipe 16d. Has been.

  The expansion valve 6 is, for example, an electric type controlled by the control device 15 and is a pressure reducing device that can be set to an arbitrary throttle amount, and is provided on the pipe 28b. Further, the expansion valve 6 converts the liquid refrigerant output from the outdoor heat exchanger 3 into a low-temperature and low-pressure liquid refrigerant during cooling operation, and converts the liquid refrigerant output from the indoor heat exchanger 5 into a low-temperature and low-pressure liquid refrigerant during heating operation. To do.

  In this embodiment, the case where the expansion valve 6 is provided on the indoor units B1 and B2 side is described as an example. However, the present invention is not limited to this, and an expansion valve is provided on the outdoor unit A side. Alternatively, expansion valves may be provided in both of the indoor units B1 and B2 and the outdoor unit A so that they can be switched and used so as to have a throttling function as necessary.

  The oil separator 7 is a gas-liquid separator that separates the refrigerating machine oil and the refrigerant that have flowed out of the compressor 1, and is provided upstream of the four-way valve 2 on the discharge side of the compressor 1. That is, the oil separator 7 is connected to the discharge side of the compressor 1 through the pipe 23a, and is connected to the four-way valve 2 through the pipe 23b. The high-pressure pipe 23 is composed of the pipe 23a and the pipe 23b. Details of the oil separator 7 and the surrounding structure will be described later.

  The accumulator 8 has a function of separating a liquid refrigerant from a gas-liquid mixed refrigerant (a refrigerant in which a gas component and a liquid component are mixed), and includes a storage unit (not shown) that stores the liquid refrigerant therein. . Although not shown, the accumulator 8 is provided with a pipe (not shown) for discharging the liquid refrigerant and a discharge valve (not shown). Thereby, it can prevent that a liquid refrigerant is introduce | transduced into the compressor 1, and can prevent that a malfunction arises in the compressor 1. FIG.

  The outdoor unit A is provided with a bypass pipe 24 that connects the liquid pipe 25 and the pipe 23b (high pressure pipe 23). The bypass pipe 24 is provided with a check valve 11 and an electromagnetic valve 10 in order from the liquid pipe 25 side. The check valve 11 has a function of allowing a fluid flow from the liquid pipe 25 side to the pipe 23b and preventing a backflow. The electromagnetic valve 10 is opened by the control device 15 when the air conditioner 100 is started. When the electromagnetic valve 10 is opened, the refrigeration oil attached to the heat transfer pipe, the pipe 26 and the liquid pipe 25 of the outdoor heat exchanger 3 can be recovered to the oil separator 7 via the bypass pipe 24. It is like that.

  Moreover, in this embodiment, unit connection piping 16 (piping 16a, 16b, 16b, 16c, 16c, 16d, gas side distributor 16s, liquid side distributor 16t) which connects the outdoor unit A and indoor unit B1, B2. , Pipes 26 and 27 in the outdoor unit A, low-pressure pipes 22 (pipes 22a and 22b), high-pressure pipes 23 (pipes 23a and 23b), bypass pipes 24, liquid pipes 25, and pipes 28a and 28a in the indoor units B1 and B2. , 28b, 28b constitute a refrigerant pipe 101 (see FIG. 1). In other words, the refrigerant pipe 101 means not only the unit connection pipe 16 that connects the outdoor unit A and the indoor units B1 and B2, but also includes all the pipes that constitute the flow path through which the refrigerant passes. This is because the refrigerant pipes in the outdoor unit A and the indoor units B1 and B2 also have different pipe lengths depending on the model, so it is necessary to determine whether the pipes are long pipes or short pipes including the refrigerant pipes.

  The control device 15 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory) storing a program, an input / output device, and the like, and is provided in the outdoor unit A. Further, the control device 15 controls the rotation speed of the motor of the compressor 1, the flow path switching of the four-way valve 2, the decompression rate of the expansion valve 6, the opening and closing of the electromagnetic valves 10, 14a and 14b, and the rotation speed of the motor of the blower (not shown). Control.

  The control device 15 is connected to a changeover switch 15a for switching whether the air conditioner 100 is a long piping system or a short piping system. In this way, by incorporating the changeover switch 15a integrally with the control device 15 on the control board constituting the control device 15, the control board can be constituted by a single substrate.

  The long pipe and the short pipe are the pipe lengths of the refrigerant pipe 101, and vary depending on the length of the unit connection pipe 16 that connects the outdoor unit A and the indoor units B1 and B2, and the outdoor unit A Varies depending on the length of the low-pressure pipe 22, high-pressure pipe 23, bypass pipe 24, liquid pipe 25, and pipes 26 and 27 in the outdoor unit A. Also, the indoor unit depends on the model of the indoor units B1 and B2. It varies depending on the length of the pipes 28a and 28b in B1 and B2.

  For example, when the maximum pipe length is X meters, the pipe longer than (X / 2) meters is longer than (X / 2) meters, and the pipe shorter than (X / 2) meters. Can be defined as short piping. Specifically, for example, X is 100. For example, when the outdoor unit A is installed in a building installed on a rooftop, the refrigerant pipe 101 is a long pipe, and when the outdoor unit A is used for home use installed on a veranda or the like, the refrigerant pipe 101 is a short pipe. It becomes.

  The changeover switch 15a is, for example, an ON / OFF switch, and is set to a long pipe when it is ON, and is set to a short pipe when it is OFF. Or, conversely, when it is ON, it may be set to a short pipe, and when it is OFF, it may be set to a long pipe.

  The control device 15 is electrically connected to a control board provided in each of the indoor units B1 and B2, and various types of operations such as switching between cooling and heating and a set temperature by operating a user's operation panel (or operation remote controller). Get the operation signal. For example, when the operation of only the indoor unit B1 is started, one compressor 1 and one outdoor heat exchanger 3 operate.

  In the outdoor unit A, a pressure sensor 20 a is provided in the pipe 23 b of the high-pressure pipe 23, and a pressure sensor 20 b is provided in the pipe 22 a of the low-pressure pipe 22. The control device 15 detects the pressure on the discharge side of the compressor 1 with the pressure sensor 20a, detects the pressure on the suction side of the compressor 1 with the pressure sensor 20b, and deviates from the allowable pressure range with respect to the reference pressure. In such a case, a function such as operation stoppage works.

  As shown in FIG. 2, the oil separator 7 has, for example, an elongated cylindrical shape in the vertical direction (vertical direction), and the high-pressure pipe 23 into which the refrigerant is introduced into the upper end portion of the side surface portion (circumferential surface portion) 7a. (Piping 23a) is connected. Further, the end portion of the high-pressure pipe 23 connected to the side surface portion 7a has a bent portion 23a1 that extends through the side surface portion 7a and the end portion that penetrates is bent downward. Thus, by making the bending part 23a1 face downward, the refrigerating machine oil can be prevented from flowing to the pipe 23b side.

  Further, on the upper surface portion 7b of the oil separator 7, a connection portion 7b1 to which the pipe 23b is connected is formed upward. A bypass pipe 24 described later is branched and connected to a pipe 23b between the oil separator 7 and the four-way valve 2 (see FIG. 1).

  Further, a long pipe outlet 18 for returning the refrigeration oil in the oil separator 7 to the suction side of the compressor 1 is formed downward on the bottom surface portion 7 c of the oil separator 7. One end of the oil return pipe 21a (first oil return pipe) is connected. The other end of the oil return pipe 21a is connected to a pipe 22a (low pressure pipe 22; see FIG. 1). The oil return pipe 21a is provided with an electromagnetic valve 14a (first shutoff valve) that is controlled to open and close by the control device 15. The bottom surface portion 7c has a tapered portion 7c1 that is inclined from the peripheral side toward the central long pipe outlet 18 side. Thereby, the refrigerating machine oil at the bottom of the oil separator 7 can be reliably discharged from the oil separator 7.

  Further, a short pipe for returning the refrigerating machine oil in the oil separator 7 to the suction side of the compressor 1 above the bottom surface part 7c in the vertical direction (vertical direction) on the side surface part 7a of the oil separator 7. An outlet 19 is formed, and one end of an oil return pipe 21b (second oil return pipe) is connected to the short pipe outlet 19. The other end of the oil return pipe 21b is connected to a pipe 22a (low pressure pipe 22) downstream from the oil return pipe 21a. In addition, the oil return pipe 21b is provided with an electromagnetic valve 14b (second cutoff valve) that is controlled to open and close by the control device 15 in the same manner as described above.

  Therefore, when the solenoid valve 14a is closed and the solenoid valve 14b is opened, the refrigeration oil that has flowed out of the compressor 1 is below the line L (see FIG. 2) to which the oil return pipe 21b is connected. It will be stored on the side. Further, when the solenoid valve 14a is opened and the solenoid valve 14b is closed, the refrigerating machine oil at the bottom of the oil separator 7 is discharged through the oil return pipe 21a without being stored in the oil separator 7. Is done.

  In the present embodiment, the case where the oil return pipes 21a and 21b are connected to the pipe 22a (low pressure pipe 22) between the four-way valve 2 and the accumulator 8 is described as an example, but the present invention is not limited thereto. Instead, the downstream ends of the oil return pipes 21 a and 21 b may be directly connected to the accumulator 8. Moreover, you may make it connect the downstream edge part of the oil return piping 21a, 21b to the piping 22b (low pressure piping 22) between the compressor 1 and the accumulator 8. FIG. In the present embodiment, the oil return pipes 21a and 21b are separately connected to the pipe 22a, but the oil return pipe 21a and the oil return pipe 21b are joined downstream of the solenoid valves 14a and 14b. You may connect the made piping to the piping 22a (or the accumulator 8, or the piping 22b).

  In the oil separator 7, the positional relationship of the short pipe outlet 19 to which the oil return pipe 21 b is connected to the long pipe outlet 18 to which the oil return pipe 21 a is connected (the volume accumulated below the line L). Is appropriately changed according to the construction conditions of the air conditioner 100 and the models of the outdoor unit A and the indoor units B1 and B2. That is, the refrigerant pipe 101 is set not to run out of refrigeration oil when the refrigerant pipe 101 is a long pipe, and so that the refrigerant oil does not become excessive when the refrigerant pipe 101 is a short pipe.

  Next, the refrigerant flow during the cooling operation of the air conditioner 100 will be described with reference to FIG. 3, and the refrigerant flow during the heating operation will be described with reference to FIG. In FIGS. 3 and 4, thick solid arrows indicate the direction in which the refrigerant flows.

  As shown in FIG. 3, during the cooling operation, the high-temperature and high-pressure refrigerant (gas state) discharged from the compressor 1 is a pipe 23 a (high-pressure pipe), an oil separator 7, a pipe 23 b (high-pressure pipe), and a four-way valve 2. Then, it passes through the pipe 26 and is condensed in the outdoor heat exchanger 3. That is, the refrigerant is condensed to liquid refrigerant by being radiated to the outdoor air by the outdoor heat exchanger 3.

  At this time, the refrigerating machine oil flowing out of the compressor 1 passes through the oil separator 7, whereby the refrigerant and the refrigerating machine oil are separated. When the solenoid valve 14a is opened and the solenoid valve 14b is closed, the refrigerating machine oil separated by the oil separator 7 is supplied from the oil return pipe 21a, the pipe 22a (low pressure pipe 22), and the accumulator 8. Then, it returns to the suction side of the compressor 1 through the pipe 22b (low pressure pipe 22). When the solenoid valve 14a is closed and the solenoid valve 14b is opened, the refrigerating machine oil separated by the oil separator 7 is supplied from the oil return pipe 21b, the pipe 22a (low pressure pipe 22), and the accumulator 8. Then, it returns to the suction side of the compressor 1 through the pipe 22b (low pressure pipe 22). Here, a capillary (not shown, pressure reducing means) for adjusting the amount of oil is provided between a connecting portion between the oil return pipe 21a and the pipe 22a and the electromagnetic valve 14a. Thereby, the amount of oil returning from the oil return pipe 21a can be adjusted to be smaller than the oil flowing into the oil separator 7. Accordingly, when it is determined that the long pipe is described later, it is possible to prevent the oil separator 7 from running out of oil while returning a large amount of oil from the oil separator 7, thereby preventing a shortage of the amount of refrigerating machine oil returned to the compressor 1. be able to. Instead of the capillary, the flow path diameter of the electromagnetic valve 14a may be made smaller than that of the electromagnetic valve 14b, or the inner diameter of the oil return pipe 21a may be made smaller than that of the oil return pipe 21b.

  The liquid refrigerant condensed in the outdoor heat exchanger 3 passes through the liquid pipe 25 and the pipes 16d, 16c, and 28b, reaches the expansion valve 6 of the indoor units B1 and B2, is decompressed, and becomes a low-temperature and low-pressure liquid refrigerant. The decompressed refrigerant is sent to the indoor heat exchanger 5 serving as an evaporator, and the refrigerant evaporates to cool the indoor air. That is, the refrigerant cools the room by absorbing the heat of the room air by the room heat exchanger 5.

  The refrigerant evaporated in the indoor heat exchanger 5 passes through the pipes 28a, 16b, 16a, and 27, returns to the suction side of the compressor 1 through the four-way valve 2, the pipe 22a, the accumulator 8, and the pipe 22b.

  As shown in FIG. 4, during the heating operation, the high-temperature and high-pressure refrigerant (gas refrigerant) discharged from the compressor 1 passes through the pipe 23a, the oil separator 7, the pipe 23b, the four-way valve 2, and the pipes 27, 16a, and 16b. It is sent to the indoor heat exchanger 5 and the refrigerant is condensed. That is, the refrigerant is condensed to liquid refrigerant by being radiated to the indoor air by the indoor heat exchanger 5. At this time, the room air is warmed by the room air from the blower (not shown) passing through the room heat exchanger 5.

  The refrigerant condensed in the indoor heat exchanger 5 is decompressed by the expansion valve 6 and becomes a low-temperature and low-pressure liquid refrigerant. The decompressed refrigerant passes through the pipes 28b, 16c, 16d, the liquid blocking valve 13, and the liquid pipe 25, and reaches the outdoor heat exchanger 3 serving as an evaporator. The evaporated refrigerant returns to the suction side of the compressor 1 through the pipe 26 and the four-way valve 2 and through the pipe 22a, the accumulator 8, and the pipe 22b.

  Next, the opening / closing control of the electromagnetic valve corresponding to each of the long piping and the short piping in the air conditioner of the present embodiment will be described with reference to FIG. The changeover switch 15a is switched to ON when the air conditioner 100 is constructed, when the air conditioner 100 is a long pipe, and is switched off when the air conditioner 100 is a short pipe. When the operation of the air conditioner 100 is stopped, the compressors 1, 1 and the blower (not shown) are all turned off (stopped), and the electromagnetic valves 10, 14a, 14b are all closed.

  As shown in FIG. 5, in step S101, the control device 15 determines whether or not the operation switches of the indoor units B1 and B2 are turned on. When the control device 15 determines that the operation switch is not turned on (S101, No), it returns to the process of step S101, and when it is determined that the operation switch is turned on (S101, Yes), Proceed to step S102.

  In step S102, the control device 15 opens the electromagnetic valve 14a, proceeds to step S103, and turns on the compressor 1 (starts driving the compressor 1). That is, when the operation switch of the air conditioner 100 is turned on (when the operation is started), for example, the air conditioner 100 is in a transitional state where the capacity of the air conditioner 100 is required, and the amount of refrigerating machine oil necessary for the compressor 1 Will also increase. In this case, by opening the solenoid valve 14a, it is possible to increase the amount of refrigeration oil returning from the long pipe outlet 18 to the compressor 1 via the oil return pipe 21a. That is, even in the air conditioner 100 determined to be a short pipe, which will be described later, by opening the electromagnetic valve 14a, in a transitional situation that requires a lot of refrigeration oil at the start of operation (at the time of startup). Can also prevent shortage of refrigerating machine oil. When the solenoid valve 14a is open, the oil return pipe 21a is provided with a capillary (not shown) as described above, so that the refrigerating machine oil in the oil separator 7 is not emptied. The state where the refrigerating machine oil is stored in the oil separator 7 is maintained.

  In step S104, the control device 15 determines whether or not the predetermined time 1 has elapsed. The predetermined time 1 is a time required from the start (startup) of the air conditioner 100 to a stable steady state of the refrigeration cycle. The predetermined time 1 is a time determined in advance by an experiment or simulation (for example, 2 Minutes). When determining that the predetermined time 1 has not elapsed (S104, No), the control device 15 repeats the process of step S104, and when determining that the predetermined time 1 has elapsed (S104, Yes). ), The process proceeds to step S105.

  In step S105, the control device 15 determines whether the changeover switch 15a is ON, that is, whether the switch is a long pipe or a short pipe. If the changeover switch 15a is set to ON during construction and the control device 15 determines that the pipe is a long pipe (S105, Yes), the control device 15 proceeds to step S113.

  As described above, when the air conditioner 100 is a long piping system (S105, Yes), a larger amount of refrigeration oil is required than the short piping system, so the solenoid valve 14a is continuously opened. By keeping it in place, it is possible to prevent the refrigeration oil from running out during long piping. In addition, as described above, the amount of the refrigeration oil flowing through the oil return pipe 21a is adjusted by the capillary (not shown), so that the amount of oil flowing from the compressor 1 is larger than the amount of oil flowing out from the oil return pipe 21a. Thus, the state where the refrigerating machine oil is stored is maintained in the oil separator 7 (the oil separator 7 is never emptied).

  In step S113, the control device 15 determines whether or not all the operation switches of the indoor units B1 and B2 are turned off, and when determining that all the operation switches are not turned off (No), If it is determined that all the operation switches have been turned off (Yes), the process proceeds to step S114, the compressor 1 is turned off (stopped), the electromagnetic valve 14a is closed, and the process returns. To do.

  Although not shown in FIG. 5, when the air conditioner 100 is a long pipe and the number of operating indoor units B1 and B2 increases (1 → 2), for example, the compressor 1 is operated. While increasing the number, control is performed to increase the number of operating outdoor heat exchangers 3 into which the refrigerant is introduced. Conversely, when the number of operating units of the indoor units B1 and B2 decreases (2 → 1), for example, control is performed to reduce the number of operating units of the compressor 1 and the outdoor heat exchanger 3, for example.

  On the other hand, in step S105, when the changeover switch 15a is turned off at the time of construction and the control device 15 determines that the pipe is a short pipe (No), the control device 15 proceeds to step S106, closes the electromagnetic valve 14a, and Then, the electromagnetic valve 14b is opened. Accordingly, the refrigerating machine oil is stored on the bottom side of the oil separator 7 (below the line L; see FIG. 2), thereby preventing the refrigerating machine oil from being excessively circulated even in a short pipe. be able to. Thus, since the refrigeration oil is stored in the oil separator 7 below the short pipe outlet 19 in the short pipe, the refrigeration oil in the oil separator 7 is emptied in the same manner as in the long pipe. Never become.

  And it progresses to step S107 and the control apparatus 15 judges whether the operation | use number of indoor unit B1, B2 increased. Whether or not the number of operating units of the indoor units B1 and B2 has increased can be determined by whether or not the control device 15 has newly acquired an operation start signal from the operation panel (not shown) of the indoor units B1 and B2. it can.

  In step S107, when the number of operating units of the indoor units B1 and B2 increases (Yes), the control device 15 starts the operation of the indoor unit B2 after that, for example, in the state where the indoor unit B1 is operating first. If it is determined that the number of operating units of the indoor units B1 and B2 has not increased (No), the process proceeds to step S111.

  In step S108, the control device 15 opens the electromagnetic valve 14a and closes the electromagnetic valve 14b. This is because, for example, when the number of operating indoor units B1 and B2 increases as in the case of the start of operation of the air conditioner 100 (starting up), for example, a transient that requires 100% of the capacity of the air conditioner 100. This is because the amount of refrigerating machine oil necessary for the compressor 1 temporarily increases. In this case, the solenoid valve 14a is opened and the amount of refrigerating machine oil returned from the long pipe outlet 18 to the compressor 1 through the oil return pipe 21a is increased, so that the compressor 1 is in a transient state. It is possible to prevent the amount of refrigerating machine oil necessary for lubrication from being insufficient. In addition, in step S108, it is not limited to the structure which opens the solenoid valve 14a, and closes the solenoid valve 14b, It is the structure which opens both the solenoid valve 14a and the solenoid valve 14b. Also good.

  In step S109, the control device 15 determines whether or not the predetermined time 2 has elapsed. The predetermined time 2 is a time required from when the operation of the air conditioner 100 is switched (a state in which the number of units operated increases) until the refrigeration cycle becomes a stable steady state, and is determined in advance by experiments or simulations. Time (for example, 2 minutes). When determining that the predetermined time 2 has not elapsed (S109, No), the control device 15 repeats the process of step S109, and when determining that the predetermined time 2 has elapsed (S109, Yes). ), And proceeds to step S110.

  In step S110, the control device 15 closes the electromagnetic valve 14a and opens the electromagnetic valve 14b. By the way, if the solenoid valve 14a is kept open even in the steady state where the refrigeration cycle is stable after the lapse of the predetermined time 2, the refrigerating machine oil becomes excessive, so the solenoid valve 14a is closed and the solenoid valve 14b. Is opened, the refrigerating machine oil is stored on the bottom side of the oil separator 7 (below the short pipe outlet 19; see FIG. 2), and the amount of refrigerating machine oil returning to the compressor 1 can be reduced.

  And it progresses to step S111 and the control apparatus 15 judges whether all the operation switches of indoor unit B1, B2 were turned off, and when all the operation switches were turned off, it progresses to step S112. The compressor 1 is stopped and the electromagnetic valve 14b is closed to return. Moreover, the control apparatus 15 returns to step S107, when all the operation switches are not turned off (S111, No). When the number of operating indoor units B1 and B2 decreases, the process is repeated so that steps S111, S107, S111,... Are performed, and the solenoid valve 14a is closed and the solenoid valve 14b is opened. If the number of operating indoor units B1 and B2 increases during this process (S107, Yes), the process proceeds to step S108.

  In this embodiment, it is determined whether the air conditioner 100 is a long pipe or a short pipe after the operation of the compressor 1 is started. However, the present invention is not limited to this, and the indoor units B1, B2 When it is determined that the operation switch is turned on, it may be determined whether the pipe is a long pipe or a short pipe. For example, if it is a long pipe, the flag is set to “1”, and if it is a short pipe, the flag is set to “0”. Instead of step S105, the flag is checked to check whether the pipe is a long pipe or a short pipe. You may make it judge whether there exists.

  As described above, the air conditioner 100 of the present embodiment includes the oil return pipe 21a including the electromagnetic valve 14a connected to the bottom surface (lower part) of the oil separator 7, and the side surface ( Control for opening / closing the solenoid valves 14a and 14b based on the oil return pipe 21b having the solenoid valve 14b connected to the upper part) and the length of the refrigerant pipe 101 (long pipe or short pipe). The apparatus 15 is provided. Thereby, when the pipe length of the refrigerant pipe 101 is long, the solenoid valve 14a is opened and the solenoid valve 14b is closed, thereby preventing a shortage of refrigerating machine oil (lubricating oil) returning to the compressor 1. . As a result, it is possible to prevent a decrease in capacity of the compressor 1 and an increase in power consumption of the compressor 1 due to a shortage of refrigeration oil in the compressor 1.

  If the piping length of the refrigerant pipe 101 is short, the solenoid valve 14a is closed and the solenoid valve 14b is opened so that the oil separator 7 holds a predetermined amount of refrigeration oil, so that a large amount of refrigeration oil can be obtained. Circulation to the refrigeration cycle can be suppressed. Therefore, the heat transfer efficiency can be prevented from being lowered due to the oil film adhering to the heat transfer pipes of the refrigerant pipe 101, the outdoor heat exchanger 3 and the indoor heat exchanger 5, and the cooling capacity and the heating capacity can be prevented from being lowered. Furthermore, the capability fall of the compressor 1 and the increase in the power consumption of the compressor 1 can be suppressed.

  Further, according to the air conditioner 100 of the present embodiment, the oil return pipe 21a (first oil return pipe) is connected to the bottom surface portion 7c of the oil separator 7, so that the oil is longer in the long pipe than in the short pipe. Therefore, a shortage of refrigerating machine oil in the compressor 1 can be prevented. Further, by connecting the oil return pipe 21b (second oil return pipe) to the side surface portion 7a of the oil separator 7, the refrigerator oil can be stably stored until the height (L) of the oil return pipe 21b is reached. Can do.

  Moreover, in the air conditioner 100 of this embodiment, when the control device 15 determines that the refrigerant pipe 101 has a long pipe length, the electromagnetic valve 14a is opened and the electromagnetic valve 14b is turned on. Control to close is performed. Thus, when the electromagnetic valve 14a is opened, the return amount of the refrigerating machine oil to the compressor 1 can be prevented from being excessive by closing the electromagnetic valve 14b. That is, if the solenoid valve 14b of the oil return pipe 21b that flows more easily than the oil return pipe 21a is not closed, the refrigeration oil flows down through the oil return pipe 21b, and the refrigeration oil in the refrigeration cycle system may become excessive. Because there is.

  Further, according to the air conditioner 100 of the present embodiment, when the control device 15 determines that the refrigerant pipe 101 has a short pipe length, the solenoid valve 14a is closed and the solenoid valve 14b is opened. When the operation is started, even if the refrigerant pipe 101 is a short pipe, the amount of refrigerating machine oil returning to the compressor 1 can be increased by opening the solenoid valve 14a, and the refrigerating machine oil at the time of starting the operation can be increased. Even in a transient state that requires a large amount, it is possible to prevent shortage of refrigerating machine oil. In the short piping system, the refrigerating machine oil in the oil separator 7 is not emptied as described above even if the solenoid valve 14a is opened.

  Further, according to the air conditioner 100 of the present embodiment, when the control device 15 determines that the refrigerant pipe 101 is a short pipe with a short length, the solenoid valve 14a is turned on when the number of indoor units B1 and B2 increases. By opening the valve, the amount of refrigerating machine oil returning to the compressor 1 can be increased in the same manner as when the operation is started, and a transient need for a large amount of refrigerating machine oil, such as an increase in the number of indoor units B1 and B2, is required. Even in such a state, the shortage of refrigerating machine oil can be prevented.

  Note that the present invention is not limited to the above-described embodiment. For example, as shown in FIG. 6, oil provided with a long pipe outlet 18 at the lower portion (lower end) of the side surface portion 7a of the oil separator 7A. It is good also as the separator 7A. Thereby, the downward protrusion from the bottom surface of the oil separator 7A can be eliminated, and the height dimension of the oil separator 7A can be kept low.

  Further, although not shown, in the air conditioner 100 of the present embodiment, the pipe diameter (inner diameter) of the oil return pipe 21a may be made smaller than the pipe diameter (inner diameter) of the oil return pipe 21b. Thereby, the pressure in the oil return pipe 21a is reduced, and the amount of refrigerating machine oil returning to the compressor 1 can be reduced. That is, when the air conditioner 100 is a very long pipe, a large amount of refrigerating machine oil returns to the compressor 1 by opening both the solenoid valves 14a and 14b. In order to prevent the refrigerating machine oil from becoming excessive as in the prior art, by reducing the pressure in the oil return pipe 21a by reducing the diameter of the oil return pipe 21a on the bottom side, The return amount of machine oil can be reduced. Therefore, even in the case of a very long pipe, the refrigerating machine oil in the oil separator 7 is not emptied, and the refrigerating machine oil is stored in the oil separator 7.

  Further, pressure reducing means such as a capillary tube may be provided on the downstream side of the electromagnetic valve 14b of the oil return pipe 21b.

  In addition, the heat pump device according to the present invention is not limited to the air conditioner 100, and the construction conditions such as a refrigeration apparatus, a refrigerator, a hot water supply machine, a vending machine, a hot air generator, a cold air generator, etc. Accordingly, the present invention can be applied to any device in which the pipe length of the refrigerant pipe changes.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 5 Indoor heat exchanger 6 Expansion valve 7, 7A Oil separator 8 Accumulator 14a Solenoid valve (1st shut-off valve)
14b Solenoid valve (second cutoff valve)
16 Unit connection pipe 16a, 16b, 16c, 16d Pipe 16s Gas side distributor 16t Liquid side distributor 18 Long pipe outlet 19 Short pipe outlet 21a Oil return pipe (first oil return pipe)
21b Oil return pipe (second oil return pipe)
22 Low-pressure piping 23 High-pressure piping 24 Bypass piping 25 Liquid piping 26, 27, 28a, 28b Piping 100 Air conditioner (heat pump device)
101 Refrigerant piping A Outdoor unit B1, B2 Indoor unit

Claims (7)

An outdoor unit comprising a compressor that compresses refrigerant, an oil separator that is provided on the discharge side of the compressor and separates lubricating oil from the compressed refrigerant, a four-way valve that switches a flow path of the refrigerant, and an outdoor heat exchanger In a heat pump apparatus comprising: a unit; an indoor unit including an indoor heat exchanger; and an expansion valve provided in at least one of the outdoor unit and the indoor unit.
A first oil return pipe connected to a lower part of the oil separator and connected to a low-pressure pipe on the suction side of the compressor;
A second oil return pipe connected to the upper part of the oil separator and connected to a low-pressure pipe on the suction side of the compressor;
A first shut-off valve provided in the first oil return pipe;
A second shut-off valve provided in the second oil return pipe;
A heat pump device comprising: a control device that controls opening and closing of the first cutoff valve and the second cutoff valve based on a length of a refrigerant pipe. The first oil return pipe is connected to a bottom surface of the oil separator;
The heat pump device according to claim 1, wherein the second oil return pipe is connected to a side surface portion of the oil separator. The first oil return pipe is connected to a lower part on the side of the oil separator,
The heat pump device according to claim 1, wherein the second oil return pipe is connected to an upper portion on a side surface side of the oil separator.   The control device opens the first solenoid valve and closes the second solenoid valve when it is determined that the pipe length of the refrigerant pipe is a long pipe. The heat pump device according to any one of claims 1 to 3.   When it is determined that the refrigerant pipe is a short pipe, the control device closes the first solenoid valve and opens the second solenoid valve. The heat pump device according to any one of claims 1 to 4, wherein the first shut-off valve is opened even when the refrigerant pipe is a short pipe. A plurality of the indoor units are provided,
2. The control device according to claim 1, wherein the control device opens the first shut-off valve when the number of the indoor units increases when it is determined that the refrigerant piping is a short pipe with a short length. Item 5. The heat pump device according to any one of items 4 to 4.   The heat pump device according to any one of claims 1 to 6, wherein a pipe diameter of the first oil return pipe is formed smaller than a pipe diameter of the second oil return pipe.

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