JP2012167897A - Outdoor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outdoor unit that can control foaming.SOLUTION: The outdoor unit includes a compressor drive and control section that starts a compressor in the outdoor unit in a low outdoor air temperature start mode when the outdoor air temperature is a first predetermined temperature or lower. In the low outdoor air temperature start mode, the compressor stops when the temperature of a delivery pipe of the compressor is a second predetermined temperature or lower upon an elapse of a first predetermined time from the start of the compressor. The compressor restarts upon an elapse of a second predetermined time from the stop of the compressor.

Description

  The present invention relates to an outdoor unit having a compressor.

  In a conventional outdoor unit, when the compressor is started, control is performed to gradually increase the operating frequency of the compressor to a target frequency (see, for example, Patent Document 1).

JP-A-9-119693

  When the outdoor unit is stopped for a long time in a low temperature environment, a large amount of refrigerant is dissolved in the lubricating oil. When the compressor is started in such a state, the refrigerant dissolved in the lubricating oil evaporates as the temperature of the lubricating oil rises. Accordingly, when the compressor is operated at a high frequency with a large amount of refrigerant dissolved in the lubricating oil at the time of starting the compressor, bubbles are generated by the refrigerant evaporated from the lubricating oil, and homing occurs.

  In the conventional control as described above, it is difficult to prevent the occurrence of homing. In particular, when the refrigerant circuit is excessively filled with the refrigerant, the amount of refrigerant dissolved in the lubricating oil increases, so that homing is more likely to occur. Therefore, control that can prevent the occurrence of homing is required.

  Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to provide an outdoor unit that can suppress the occurrence of homing.

  An outdoor unit according to a first aspect of the present invention is an outdoor unit having a compressor, and includes an outside air temperature detecting unit that detects an outside air temperature, a compressor temperature detecting unit that detects the temperature of the compressor, and the compressor. Control means for controlling, the control means as a control mode of the compressor, the control means for starting the compressor under a condition that the outside air temperature detected by the outside air temperature detecting means is not more than a first predetermined temperature. An outside air temperature starting mode, and in the low outside air temperature starting mode, a compressor temperature detected by the compressor temperature detecting means when a first predetermined time has elapsed after starting the compressor is a second predetermined temperature. When the temperature is equal to or lower than the temperature, the compressor is stopped, and the compressor is restarted when a second predetermined time elapses after the compressor is stopped.

  In this outdoor unit, when the compressor is started under a low outdoor temperature, the refrigerant dissolved in the lubricating oil evaporates by temporarily stopping the compressor after the starting, and the amount of refrigerant in the lubricating oil decreases. Therefore, it is possible to suppress homing from occurring when the compressor is restarted.

  In the outdoor unit according to the second aspect of the invention, in the outdoor unit according to the first aspect of the invention, the control means restarts the compressor when the second predetermined time has elapsed after stopping the compressor. When the outside air temperature detected by the detecting means is equal to or lower than the first predetermined temperature, the compressor is started in the low outside air temperature starting mode, and the outside air temperature detected by the outside air temperature detecting means falls below the first predetermined temperature. When it exceeds, control in the low outside air temperature starting mode is not performed.

  In this outdoor unit, when the outside air temperature is equal to or lower than the first predetermined temperature, the starting in the low outside air temperature starting mode can be repeated, so that homing can be reliably suppressed. Further, once the compressor is started and then stopped, the refrigerant pressure decreases, but the compressor temperature is maintained at a high temperature. Therefore, by repeating the start-up in the low outside air temperature start-up mode, while suppressing the occurrence of homing, the compressor temperature is quickly raised so that the circulation of the lubricating oil is stabilized and there is no possibility of homing occurring. Can do.

  An outdoor unit according to a third aspect of the present invention is an outdoor unit having a compressor, and includes an outside air temperature detecting unit that detects an outside air temperature, a compressor temperature detecting unit that detects the temperature of the compressor, and the compressor. Control means for controlling, the control means as a control mode of the compressor, the control means for starting the compressor under a condition that the outside air temperature detected by the outside air temperature detecting means is not more than a first predetermined temperature. A compressor temperature detected by the compressor temperature detecting means when a first predetermined time has elapsed since the compressor was started at the first frequency in the low outside temperature startup mode. Is lower than the second predetermined temperature, the operating frequency of the compressor is changed to a second frequency lower than the first frequency, and when the second predetermined time has elapsed after the change to the second frequency, Operating frequency Larger than the second frequency.

  In this outdoor unit, when the compressor is started under a low outside air temperature, it is possible to suppress bubbles from being generated by the refrigerant evaporating from the lubricating oil by lowering to the second frequency after starting at the first frequency. At this time, the refrigerant evaporates from the lubricating oil, so that the amount of refrigerant in the lubricating oil decreases. Therefore, it is possible to suppress the occurrence of homing when the operating frequency of the compressor is made higher than the second frequency again.

  In the outdoor unit according to a fourth aspect of the invention, in the outdoor unit according to the third aspect of the invention, the control means is detected by the compressor temperature detection means when a second predetermined time has elapsed after changing to the second frequency. When the compressor temperature is equal to or lower than a second predetermined temperature, the operation frequency of the compressor is set to the first frequency, and the control in the low outside air temperature starting mode is started from that time, and the compressor temperature detection is performed. When the compressor temperature detected by the means exceeds the second predetermined temperature, the operation frequency of the compressor is set to a third frequency higher than the first frequency.

  In this outdoor unit, the control in the low outside air temperature activation mode can be repeated until the compressor temperature exceeds the second predetermined temperature, so that homing can be reliably suppressed. Further, by starting the compressor at the first frequency and then lowering the compressor to the second frequency, the refrigerant pressure is reduced, but the compressor temperature is maintained at a high temperature. Therefore, by repeating the control in the low outside air temperature starting mode, the compressor temperature is quickly raised while suppressing the occurrence of homing, so that the circulation of the lubricating oil is stabilized and there is no possibility of homing occurring. Can do. Furthermore, when the compressor temperature exceeds the second predetermined temperature and there is no risk of homing, the frequency can be set higher than the frequency at the time of startup.

  An outdoor unit according to a fifth aspect of the present invention is the outdoor unit according to the third or fourth aspect of the present invention, wherein the second frequency is the lowest frequency that can be operated by the compressor.

  In this compressor, it is possible to reliably suppress the occurrence of homing by lowering the frequency to the lowest frequency after starting the compressor.

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, when the compressor is started under a low outside air temperature, the refrigerant dissolved in the lubricating oil is evaporated by temporarily stopping the compressor after the starting, and the amount of refrigerant in the lubricating oil is reduced. Therefore, it is possible to suppress homing from occurring when the compressor is restarted.

  In the second invention, when the outside air temperature is equal to or lower than the first predetermined temperature, the starting in the low outside air temperature starting mode can be repeated, so that homing can be reliably suppressed. Further, once the compressor is started and then stopped, the refrigerant pressure decreases, but the compressor temperature is maintained at a high temperature. Therefore, by repeating the start-up in the low outside air temperature start-up mode, while suppressing the occurrence of homing, the compressor temperature is quickly raised so that the circulation of the lubricating oil is stabilized and there is no possibility of homing occurring. Can do.

  In 3rd invention, when starting a compressor under low external temperature, it can suppress that a bubble arises with the refrigerant | coolant which evaporates from lubricating oil by lowering to a 2nd frequency after starting with a 1st frequency. At this time, the refrigerant evaporates from the lubricating oil, so that the amount of refrigerant in the lubricating oil decreases. Therefore, it is possible to suppress the occurrence of homing when the operating frequency of the compressor is made higher than the second frequency again.

  In the fourth aspect of the invention, since the control in the low outside air temperature start mode can be repeated until the compressor temperature exceeds the second predetermined temperature, homing can be reliably suppressed. Further, by starting the compressor at the first frequency and then lowering the compressor to the second frequency, the refrigerant pressure is reduced, but the compressor temperature is maintained at a high temperature. Therefore, by repeating the control in the low outside air temperature starting mode, the compressor temperature is quickly raised while suppressing the occurrence of homing, so that the circulation of the lubricating oil is stabilized and there is no possibility of homing occurring. Can do. Furthermore, when the compressor temperature exceeds the second predetermined temperature and there is no risk of homing, the frequency can be set higher than the frequency at the time of startup.

  In 5th invention, it can suppress reliably that homing generate | occur | produces by lowering to the lowest frequency after starting a compressor.

It is a circuit diagram showing a schematic structure of a heating device provided with an outdoor unit concerning a 1st embodiment of the present invention. It is a circuit diagram which shows the detailed structure of the heating apparatus of FIG. It is a block diagram which shows schematic structure of the control part which controls the outdoor unit of FIG. It is a flowchart of the main process performed by the control part of FIG. It is a flowchart of the low outside temperature starting mode process shown in FIG. It is a graph which shows an example of the time change of the operating frequency of a compressor in case the compressor drive control part shown in FIG. 3 controls a compressor in normal mode. It is a graph which shows an example of the time change of the discharge pipe temperature and operating frequency of a compressor in case the compressor drive control part shown in Drawing 3 starts a compressor in low outside temperature starting mode. It is a block diagram which shows schematic structure of the control part which controls the outdoor unit concerning 2nd Embodiment of this invention. It is a graph which shows an example of the time change of the discharge pipe temperature of a compressor, and an operating frequency when the compressor drive control part shown in FIG. 8 starts a compressor in the low external temperature starting mode. It is a flowchart of the low outdoor temperature starting mode process performed by the control part shown in FIG.

<First Embodiment>
Hereinafter, the heating apparatus 1 provided with the outdoor unit 10 concerning 1st Embodiment of this invention is demonstrated, referring drawings.

(Configuration of heating device 1)
As shown in FIG. 1, the heating device 1 includes an outdoor unit 10, a heating unit 40, and a plurality of floor heating panels 60 connected to the heating unit 40. The outdoor unit 10 of the present embodiment is a multi-outdoor unit that can connect a plurality of indoor units. In this embodiment, it replaces with an indoor unit with respect to the outdoor unit 10, and the heating unit 40 is connected and the heating apparatus 1 is comprised.

  The outdoor unit 10 has a plurality of pairs (three pairs in the present embodiment) of connecting portions 11a and 11b to which either the heating unit 40 or the indoor unit is connected. 1 shows a state in which two heating units 40 are connected to the outdoor unit 10, the number of heating units 40 connected to the outdoor unit 10 may be one, or 3 It may be a table.

  The outdoor unit 10 includes a refrigerant flow path formed by connecting the compressor 12, the outdoor heat exchanger 15, and the electric expansion valve 16 in this order between the connection part 11a and the connection part 11b. More specifically, the discharge pipe 12a and the suction pipe 12b of the compressor 12 are connected to the primary port of the four-way switching valve 13 in the refrigerant flow path. An accumulator 14 is interposed in the suction pipe 12b. A discharge pipe temperature detection thermistor 25 is attached to the discharge pipe 12a. On the other hand, to the secondary port of the four-way switching valve 13, a first gas pipe 20 a reaching the header 17 and a second gas pipe 20 b reaching the outdoor heat exchanger 15 are connected. The header 17 branches the first gas pipe 20 a into three branch gas pipes 21. The end of each branch gas pipe 21 opposite to the header 17 side is connected to the connection portion 11a. Each branch gas pipe 21 is provided with a gas pipe temperature detection thermistor 26.

  Three branch liquid pipes 22 extending from the header 18 are connected to the three connection portions 11b, respectively. An electric expansion valve 16 is interposed in the branch liquid pipe 22. The electric expansion valve 16 can change the amount of refrigerant sent to the heating unit 40 or the indoor unit by changing its opening, and can function as a decompression mechanism. Further, a liquid pipe temperature detection thermistor 27 is provided between the electric expansion valve 16 and the connecting portion 11b in the branch liquid pipe 22, respectively. The header 18 joins the three branch liquid pipes 22 to the liquid pipe 20c. The end of the liquid pipe 20 c opposite to the header 18 side is connected to the outdoor heat exchanger 15. The outdoor heat exchanger 15 is provided with an outdoor heat exchanger temperature detection thermistor 28.

  The outdoor unit 10 includes an outside air temperature detection thermistor 29 and a control unit 30 in addition to the above-described refrigerant flow path. The control unit 30 is connected to a control unit 50 of the heating unit 40 described later through signal lines.

  The heating unit 40 includes connection portions 41a and 41b for connecting to the outdoor unit 10, and a refrigerant flow path connecting the connection portion 41a and the connection portion 41b. The refrigerant flow path is provided with a water heat exchanger 42, and the refrigerant flowing from the connection portion 41 a flows to the connection portion 41 b via the water heat exchanger 42. A hydrothermal exchange temperature detection thermistor 55 is attached to the water heat exchanger 42. The pipe connecting the water heat exchanger 42 and the connecting portion 41a is provided with a pressure sensor 56 that detects the pressure of the refrigerant flowing into the water heat exchanger 42, and the water heat exchanger 42 An outflow refrigerant temperature detection thermistor 57 is attached to the pipe connecting the connection portion 41b. The heating unit 40 is provided with a control unit 50 that performs electrical control of the heating unit 40. The detailed configuration of the heating unit 40 will be described later.

  In the heating device 1, the connection part 11 a of the outdoor unit 10 and the connection part 41 a of the heating unit 40 are connected by a communication pipe 9 a, and the connection part 11 b of the outdoor unit 10 and the connection part 41 b of the heating unit 40 communicate with each other. They are connected by a tube 9b. And the heating apparatus 1 is comprised by the outdoor unit 10, the heating unit 40, the some floor heating panel 60, and the wired remote control 2. FIG. In the wired remote controller 2, an operation for starting / stopping operation and temperature setting are performed by the user.

  The outdoor unit 10 has the above-described refrigerant flow path accommodated in the casing 10a, and the heating unit 40 has the above-described refrigerant flow path and a hot water flow path described below accommodated in the casing 40a. Is. That is, the outdoor unit 10 and the heating unit 40 are configured separately, and they are connected by connecting pipes 9a and 9b. And in the heating apparatus 1, the refrigerant | coolant flow path comprised in the outdoor unit 10 and the refrigerant | coolant flow path comprised in the heating unit 40 are connected by connecting pipe 9a, 9b, and the compressor 12, water heat exchange A refrigerant circulation circuit in which the vessel 42, the electric expansion valve 16, and the outdoor heat exchanger 15 are connected in order is formed. In this refrigerant circulation circuit, the refrigerant sent from the outdoor unit 10 through the connecting pipe 9a flows into the heating unit 40 from the connection part 41a, passes through the water heat exchanger 42, and then flows out from the connection part 41b. .

(Configuration of heating unit 40)
As shown in FIG. 2, the heating unit 40 includes a plurality of pairs (four pairs in this embodiment) of connection portions 43 a and 43 b for connecting a plurality of floor heating panels 60 in addition to the above-described refrigerant flow path. And a hot water channel connecting the connecting portion 43a and the connecting portion 43b.

  Four return branch pipes 51 extending from the header 47 are connected to the four connection portions 43a. The header 47 joins the four return branch pipes 51 to the return pipe 50a. The end of the return pipe 50 a opposite to the header 47 side is connected to the water heat exchanger 42. A return water temperature detection thermistor 58 is attached to the return pipe 50a.

  In addition to the return pipe 50a described above, the water heat exchanger 42 is connected with an outgoing pipe 50b that reaches the header 48. An expansion tank 45 and a circulation pump 46 are interposed in the forward pipe 50b in order from the water heat exchanger 42 side. Further, a forward water temperature detection thermistor 59 is provided between the expansion tank 45 and the circulation pump 46 in the forward pipe 50b. The forward water temperature detection thermistor 59 may be attached between the circulation pump 46 and the header 48. The header 48 branches the forward pipe 50 b into four forward branch pipes 52. The end of each forward branch pipe 52 opposite to the header 48 side is connected to the connection portion 43b. Each forward branch pipe 52 is provided with a thermal valve 53. The thermal valve 53 is for changing the flow rate of the temperature-controlled water sent to the floor heating panel 60 connected to the heating unit 40.

  A floor heating panel 60 is attached to each of the four pairs of connection portions 43 a and 43 b provided in the heating unit 40. And the connection part 43a and the connection part 43b as an edge part of the warm water flow path comprised in the heating unit 40 are connected via the floor heating panel 60, and the water heat exchanger 42, the circulation pump 46, thermal motion A hot water circulation circuit in which the valve 53 and the floor heating panel 60 are sequentially connected is formed. Therefore, in the heating apparatus 1, the temperature-controlled water heated by the hydrothermal exchanger 42 through which the refrigerant from the outdoor unit 10 flows is supplied to the floor heating panel 60, and the temperature-controlled water flowing out from the floor heating panel 60 is converted into hydrothermal water. It can be returned to the exchanger 42.

(Control unit 30)
Next, the control unit 30 that controls the outdoor unit 10 will be described with reference to FIG. The control unit 30 includes an outside air temperature determination unit 31, a compressor temperature determination unit 32, and a compressor drive control unit 33.

  The outside air temperature determination unit 31 determines whether or not the outside air temperature detected by the outside air temperature detection thermistor 29 is equal to or lower than a first predetermined temperature. The first predetermined temperature is a low temperature at which homing may occur if the outside air temperature is equal to or lower than that temperature. In the present embodiment, the first predetermined temperature is −5 ° C. The compressor temperature determination unit 32 determines whether or not the temperature of the discharge pipe 12a detected by the discharge pipe temperature detection thermistor 25 is equal to or lower than a second predetermined temperature. The second predetermined temperature is a high temperature at which there is no possibility of homing if the temperature of the discharge pipe 12a exceeds the temperature. In the present embodiment, the second predetermined temperature is 35 ° C.

  The compressor drive control unit 33 controls the start / stop timing of the compressor 12 and the operation frequency of the compressor 12. The compressor drive control unit 33 has two modes, a normal mode and a low outside air temperature activation mode, as control modes of the compressor 12, and the determination by the outside air temperature determination unit 31 and the compressor temperature determination unit 32 is performed. Based on this, the two control modes are switched.

  Here, the normal mode is a mode in which the operation frequency of the compressor 12 is controlled to increase stepwise until the target frequency is reached, as shown in FIG. On the other hand, the low outside air temperature start mode is a mode in which the start and stop of the compressor 12 are repeated as shown in FIG. Specifically, the temperature of the discharge pipe 12a detected by the compressor temperature determination unit 32 when the first predetermined time elapses after the compressor 12 is started at an operation frequency lower than the target frequency is equal to or lower than the second predetermined temperature. If so, the compressor 12 is stopped. Further, after the compressor 12 is stopped, the compressor 12 is restarted when the second predetermined time has elapsed. In the example shown in FIG. 7, the low outside air temperature activation mode is completed at time t5, and thereafter, control in the normal mode is performed. The target frequency is determined by the set temperature of the floor heating panel 60 set by the user. 6 and 7 show a case where the target frequency is 65 Hz, this is an example.

(Control procedure)
Here, the procedure of the main process (start-up mode determination process) performed by the control unit 30 will be described with reference to FIG.
First, the outside air temperature determination unit 31 determines whether or not the outside air temperature is equal to or lower than a first predetermined temperature (step S1). When it is determined that the outside air temperature is equal to or lower than the first predetermined temperature (step S1: YES), the compressor drive control unit 33 starts the compressor 12 in the low outside air temperature starting mode (step S2). ). The processing procedure in the low outside air temperature activation mode will be described in detail later. On the other hand, when it is determined that the outside air temperature exceeds the first predetermined temperature (step S1: NO), the compressor 12 is started in the normal mode by the compressor drive control unit 33 (step S3).

Next, a processing procedure in the low outside air temperature activation mode will be described with reference to FIG.
First, the compressor 12 is started at an operation frequency lower than the target frequency (step S21). That is, in the example shown in FIG. 7, the compressor 12 is started at 45 Hz lower than the target frequency (65 Hz). Then, it is determined whether or not the first predetermined time has elapsed since the compressor 12 was started (step S22). When it is determined that the first predetermined time has elapsed (step S22: YES), the compressor temperature determination unit 32 determines whether or not the temperature of the discharge pipe 12a is equal to or lower than the second predetermined temperature ( Step S23).

  When the temperature of the discharge pipe 12a is equal to or lower than the second predetermined temperature (step S23: YES), the driving of the compressor 12 is stopped (step S24). That is, in the example shown in FIG. 7, the temperature of the discharge pipe 12a at the time t1 when the first predetermined time has elapsed since the start of the compressor 12 is 22 ° C., which is equal to or lower than the second predetermined temperature (35 ° C.). Therefore, the drive of the compressor 12 is stopped at time t1.

  Thereafter, it is determined whether or not the second predetermined time has elapsed since the drive of the compressor 12 was stopped (step S25). If it is determined that the second predetermined time has elapsed (step S25: YES), the process returns to step S1 of the above-described activation mode determination process to determine whether or not the outside air temperature is equal to or lower than the first predetermined temperature. Is called. When the outside air temperature is equal to or lower than the first predetermined temperature, the compressor 12 is started again in the low outside air temperature starting mode. That is, in the example shown in FIG. 7, the compressor 12 is started again at 45 Hz at time t2 when the second predetermined time has elapsed.

  On the other hand, when the temperature of the discharge pipe 12a exceeds the second predetermined temperature in step S23 (step S23: NO), the low outside air temperature activation mode is terminated. Note that after the low outside air temperature start-up mode ends, the control is switched to the normal mode. In the example shown in FIG. 7, the temperature of the discharge pipe 12a at time t5 when the first predetermined time has elapsed after starting the compressor 12 in the low outside temperature start mode for the third time is 49 ° C., and the second predetermined temperature. (35 ° C) is exceeded. Therefore, at the time t5, the low temperature startup mode ends and the mode is switched to the normal mode, and the operating frequency of the compressor 12 is raised to the target frequency of 65 Hz.

(Features of outdoor unit 10)
The control unit 30 of the outdoor unit 10 of the present embodiment includes a compressor drive control unit 33 that starts the compressor 12 in the low outside air temperature start mode when the outside air temperature is equal to or lower than the first predetermined temperature. In the low outside air temperature starting mode, the compressor 12 is stopped when the temperature of the discharge pipe 12a of the compressor 12 is equal to or lower than the second predetermined temperature after the first predetermined time has elapsed since the compressor 12 was started. Then, after the compressor 12 is stopped, the compressor 12 is restarted when the second predetermined time has elapsed.
Therefore, when starting the compressor 12 under a low outside air temperature, the refrigerant dissolved in the lubricating oil evaporates by temporarily stopping the compressor 12 after the starting, and the amount of refrigerant in the lubricating oil decreases. Therefore, when the compressor 12 is restarted, occurrence of homing can be suppressed.
In the present embodiment, as described above, the heating unit 1 is configured by connecting the heating unit 40 to the outdoor unit 10 that is a multi-outdoor unit to which a plurality of indoor units can be connected instead of the indoor unit. is doing. Here, when the multi-outdoor unit is shipped from the manufacturing factory, an amount of refrigerant determined in consideration of the volume of the indoor heat exchanger of the plurality of indoor units connected to the outdoor unit is enclosed, The volume of the water heat exchanger of the heating unit is often smaller than the volume of the indoor heat exchanger of the indoor unit. Therefore, in the heating device 1, the refrigerant circuit is in an excessively filled state with the refrigerant. Therefore, since homing is likely to occur, it is effective to apply the present invention.

Further, in the outdoor unit 10 of the present embodiment, when the compressor drive control unit 33 restarts the compressor 12 when the second predetermined time has elapsed after stopping the compressor 12, the outside air temperature is equal to or lower than the first predetermined temperature. In some cases, the compressor 12 is activated in the low outside air temperature activation mode, and when the outside air temperature exceeds the first predetermined temperature, the compressor 12 is activated in the normal mode.
Therefore, when the outside air temperature is equal to or lower than the first predetermined temperature, the starting in the low outside air temperature starting mode can be repeated, so that homing can be reliably suppressed. Further, once the compressor 12 is started and then stopped, the refrigerant pressure decreases, but the temperature of the discharge pipe 12a is maintained at a high temperature. Therefore, by repeating the start-up in the low outside air temperature start-up mode, while suppressing the occurrence of homing, the temperature of the discharge pipe 12a is quickly raised, so that the circulation of the lubricating oil is stabilized and there is no risk of homing occurring. can do.

Second Embodiment
Next, a second embodiment of the present invention will be described.
The outdoor unit of the present embodiment is different from the first embodiment in the function of the compressor drive control unit 33a of the control unit 30 shown in FIG. Since other configurations and functions are the same as those of the first embodiment, the same reference numerals are used and description thereof is omitted as appropriate.

  Similarly to the compressor drive control unit 33 of the first embodiment, the compressor drive control unit 33a sets the control mode of the compressor 12 to the normal mode based on the determination of the outside air temperature determination unit 31 and the compressor temperature determination unit 32. Or switch to low outside air temperature startup mode. As shown in FIG. 9, the outside air temperature startup mode of the present embodiment is configured such that the frequency of the compressor 12 is between the first frequency f1 (= 45 Hz) and the second frequency f2 (= 20 Hz) smaller than the first frequency f1. The mode is switched alternately with. Specifically, when the temperature of the discharge pipe 12a detected by the compressor temperature determination unit 32 after the first predetermined time has elapsed since the compressor 12 was started at the first frequency f1 is equal to or lower than the second predetermined temperature. The operating frequency of the compressor 12 is changed to the second frequency f2. In addition, the operating frequency of the compressor 12 is set to be larger than the second frequency f2 when the second predetermined time has elapsed after the change to the second frequency. In the example shown in FIG. 9, the low outside air temperature startup mode ends at time t5, and thereafter, control in the normal mode is performed. In the present embodiment, the second frequency f <b> 2 is the lowest frequency that can be operated by the compressor 12. Further, the target frequency f3 (third frequency) is larger than the first frequency f1.

(Control procedure)
Here, a processing procedure in the low outside air temperature activation mode of the present embodiment will be described with reference to FIG.
First, the compressor 12 is started at the first frequency f1 (step S31). Then, it is determined whether or not the first predetermined time has elapsed since the compressor 12 was started (step S32). When it is determined that the first predetermined time has elapsed (step S32: YES), the compressor temperature determination unit 32 determines whether or not the temperature of the discharge pipe 12a is equal to or lower than the second predetermined temperature ( Step S33).

  When the temperature of the discharge pipe 12a is equal to or lower than the second predetermined temperature (step S33: YES), the operating frequency of the compressor 12 is changed from the first frequency f1 to the second frequency f2 (step S34). That is, in the example shown in FIG. 9, the temperature of the discharge pipe 12a at the time t1 when the first predetermined time has elapsed since the start of the compressor 12 is 22 ° C., which is equal to or lower than the second predetermined temperature (35 ° C.). Therefore, at the time t1, the frequency of the compressor 12 is changed from the first frequency f1 to the second frequency f2.

  Thereafter, it is determined whether or not the second predetermined time has elapsed since the operating frequency of the compressor 12 was changed to the second frequency f2 (step S35). When it is determined that the second predetermined time has elapsed (step S35: YES), the compressor temperature determination unit 32 determines whether or not the temperature of the discharge pipe 12a is equal to or lower than the second predetermined temperature ( Step S36).

  When the temperature of the discharge pipe 12a is equal to or lower than the second predetermined temperature (step S36: YES), the operating frequency of the compressor 12 is changed from the second frequency f2 to the first frequency f1 (step S37), and the above-described steps. Returning to S32, it is determined whether or not the first predetermined time has elapsed. That is, in the example shown in FIG. 9, the temperature of the discharge pipe 12a at time t2 when the second predetermined time has elapsed after the frequency of the compressor 12 is changed to the second frequency f2 is 22 ° C., and the second predetermined temperature ( 35 ° C.) or less. Therefore, at time t2, the frequency of the compressor 12 is changed from the second frequency f2 to the first frequency f1.

  On the other hand, when the temperature of the discharge pipe 12a exceeds the second predetermined temperature (step S36: NO), the low outside air temperature activation mode ends. In addition, after the low outside air temperature start-up mode ends, the control is switched to the control in the normal mode, and the operation frequency of the compressor 12 is raised from the second frequency f2 to the target frequency f3.

  In step S33, when the temperature of the discharge pipe 12a exceeds the second predetermined temperature (step S33: NO), the low outside air temperature start-up mode ends. Note that after the low outside air temperature start-up mode ends, the control is switched to the normal mode. In the example shown in FIG. 9, the temperature of the discharge pipe 12a at time t5 when the first predetermined time elapses after the operation of the compressor 12 at the first frequency f1 is started for the third time is 49 ° C. 2 Exceeds the predetermined temperature (35 ° C). Therefore, at the time t5, the low temperature startup mode ends and the mode is switched to the normal mode, and the operating frequency of the compressor 12 is raised to the target frequency f3.

In the present embodiment, in the low outside air temperature starting mode, the temperature of the discharge pipe 12a of the compressor 12 is equal to or lower than the second predetermined temperature after the first predetermined time has elapsed since the compressor 12 was started at the first frequency f1. In this case, the operating frequency of the compressor 12 is changed from the first frequency f1 to the second frequency f2 (<f1). Then, after the operating frequency of the compressor 12 is changed to the second frequency f2, the operating frequency of the compressor 12 is made larger than the second frequency when a second predetermined time has elapsed.
Accordingly, when starting the compressor 12 under a low outside air temperature, the refrigerant that evaporates from the lubricating oil by lowering the operating frequency of the compressor 12 to the second frequency f2 after starting the compressor 12 at the first frequency f1. Can suppress the generation of bubbles. At this time, the refrigerant evaporates from the lubricating oil, so that the amount of refrigerant in the lubricating oil decreases. Therefore, it is possible to suppress the occurrence of homing when the operating frequency of the compressor 12 is made higher than the second frequency f2 again.

Further, in the present embodiment, the compressor drive control unit 33a changes the operating frequency of the compressor 12 to the second frequency f2, and after the second predetermined time has elapsed, the temperature of the discharge pipe 12a is equal to or lower than the second predetermined temperature. In some cases, the operating frequency of the compressor 12 is set to the first frequency f1. Then, from that time point, the process returns to the upstream process of the processing procedure in the low outside air temperature starting mode (after starting at the first frequency f1), and the control in the low outside air temperature starting mode is started. On the other hand, when the temperature of the discharge pipe 12a exceeds the second predetermined temperature, the low outside air temperature startup mode is terminated and the control is switched to the control in the normal mode, and the operation frequency of the compressor 12 is raised to the target frequency f3.
Therefore, the control in the low outside air temperature activation mode can be repeated until the temperature of the discharge pipe 12a exceeds the second predetermined temperature and there is no risk of homing, so that homing can be reliably suppressed. Further, by starting the compressor 12 at the first frequency f1 and then lowering it to the second frequency f2, the refrigerant pressure is reduced, but the temperature of the discharge pipe 12a is maintained at a high temperature. Therefore, by repeating the control in the low outside air temperature starting mode, the temperature of the discharge pipe 12a is quickly raised while suppressing the occurrence of homing, so that the circulation of the lubricating oil is stabilized and there is no possibility of homing occurring. can do. Furthermore, when the temperature of the discharge pipe 12a exceeds the second predetermined temperature and there is no possibility of homing, the target frequency f3 can be set.

  Further, in the present embodiment, the second frequency f <b> 2 is the lowest frequency that can be operated by the compressor 12. Therefore, it can suppress reliably that homing generate | occur | produces by lowering to the lowest frequency after starting the compressor 12.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, although the case where the heating unit 40 is connected to the outdoor unit 10 has been described in the first and second embodiments described above, the present invention is not limited to this. That is, a wall-mounted indoor unit or the like may be connected to the outdoor unit 10.

  In the first and second embodiments described above, the discharge pipe temperature detection thermistor 25 is attached to the discharge pipe 12 a of the compressor 12, and the compressor temperature determination unit 32 is detected by the discharge pipe temperature detection thermistor 25. Although the case where it is determined whether or not the temperature of the discharge pipe 12a is equal to or lower than the second predetermined temperature has been described, the present invention is not limited to this. For example, the compressor temperature determination unit 32 is configured to make a determination based on a detection temperature of a sensor that detects a temperature correlated with the temperature of the lubricating oil in the compressor 12 such as a thermistor attached to the main body of the compressor 12. That's fine.

  In the first embodiment described above, when the compressor drive control unit 33 restarts the compressor 12 when the second predetermined time has elapsed after stopping the compressor 12, the outside air temperature is equal to or lower than the first predetermined temperature. In this case, the case where the compressor 12 is started in the low outside air temperature start mode and the compressor 12 is started in the normal mode when the outside air temperature exceeds the first predetermined temperature has been described. Not. That is, the compressor drive control unit 33 once starts the compressor 12 in the low outside air temperature start mode and stops the compressor 12, regardless of whether the outside air temperature is equal to or lower than the first predetermined temperature. The computer may be restarted in the normal mode. Further, once the compressor 12 is started in the low outside temperature starting mode and the compressor 12 is stopped, it may be always restarted in the low outside temperature starting mode.

  In addition, in the above-described first embodiment, the compressor drive control unit 33 sets the temperature of the discharge pipe 12a to the second predetermined temperature after the first predetermined time has elapsed after starting the compressor 12 in the low outside air temperature start mode. In the case of exceeding, the control is switched to the control in the normal mode, and the operation frequency of the compressor 12 is set as the target frequency. However, the present invention is not limited to this. That is, for example, the operating frequency of the compressor 12 may not be immediately set to the target frequency when the first predetermined time elapses, but may be gradually increased to the target frequency.

  Furthermore, in the second embodiment described above, the compressor drive control unit 33a changes the operating frequency of the compressor 12 to the second frequency f2, and the temperature of the discharge pipe 12a is changed to the second predetermined temperature when the second predetermined time has elapsed. In the case of the following, the operation frequency of the compressor 12 is set to the first frequency f1, and the control in the low outside air temperature starting mode is started from that time, and the temperature of the discharge pipe 12a exceeds the second predetermined temperature. In this case, the case of switching to the control in the normal mode has been described, but the present invention is not limited to this. That is, after changing the operating frequency of the compressor 12 to the second frequency f2, the compressor drive control unit 33a sets the operating frequency of the compressor 12 to the first frequency f1 regardless of the temperature of the discharge pipe 12a. It may be switched to control in the normal mode.

  In the second embodiment, the case where the second frequency f2 is the lowest frequency that can be operated by the compressor 12 has been described. However, the second frequency f2 is lower than the lowest frequency that can be operated by the compressor 12. May be larger.

  Further, in the above-described second embodiment, the compressor drive control unit 33a determines that the temperature of the discharge pipe 12a exceeds the second predetermined temperature when the first predetermined time elapses after the compressor 12 is started at the first frequency f1. In this case, the control is switched to the control in the normal mode and the operation frequency of the compressor 12 is set to the target frequency f3. However, the present invention is not limited to this. That is, for example, instead of immediately setting the operating frequency of the compressor 12 to the target frequency f3 when the first predetermined time has elapsed, the operating frequency may be increased stepwise to the target frequency f3.

  In the second embodiment described above, the compressor drive control unit 33a changes the temperature of the discharge pipe 12a to the second predetermined temperature when the second predetermined time elapses after the operating frequency of the compressor 12 is changed to the second frequency f2. Is exceeded, the control is switched to the control in the normal mode, and the operation frequency of the compressor 12 is set to the target frequency f3. However, the present invention is not limited to this. That is, when the temperature of the discharge pipe 12a exceeds the second predetermined temperature, the operating frequency of the compressor 12 may be set to a frequency higher than the first frequency f1, and the target frequency f3 is not necessarily required.

  If this invention is utilized, generation | occurrence | production of homing can be suppressed.

10 outdoor unit 12 compressor 25 discharge pipe temperature detection thermistor (compressor temperature detection means)
29 Outside temperature detection thermistor (outside temperature detection means)
33, 33a Compressor drive control unit (control means)

Claims (5)

An outdoor unit having a compressor,
An outside air temperature detecting means for detecting the outside air temperature,
Compressor temperature detecting means for detecting the temperature of the compressor;
Control means for controlling the compressor,
The control means has a low outside air temperature start mode for starting the compressor as a control mode of the compressor under a condition that the outside air temperature detected by the outside air temperature detecting means is equal to or lower than a first predetermined temperature,
In the low outside air temperature starting mode, when the compressor temperature detected by the compressor temperature detecting means is less than or equal to a second predetermined temperature after the first predetermined time has elapsed since starting the compressor, the compressor is turned off. An outdoor unit that stops and restarts the compressor when a second predetermined time elapses after the compressor is stopped. The control means includes
When restarting the compressor after the second predetermined time has elapsed after stopping the compressor,
When the outside air temperature detected by the outside air temperature detecting means is equal to or lower than a first predetermined temperature, the compressor is started in the low outside air temperature starting mode,
2. The outdoor unit according to claim 1, wherein when the outside air temperature detected by the outside air temperature detecting unit exceeds a first predetermined temperature, the control in the low outside air temperature starting mode is not performed. An outdoor unit having a compressor,
An outside air temperature detecting means for detecting the outside air temperature,
Compressor temperature detecting means for detecting the temperature of the compressor;
Control means for controlling the compressor,
The control means has a low outside air temperature start mode for starting the compressor as a control mode of the compressor under a condition that the outside air temperature detected by the outside air temperature detecting means is equal to or lower than a first predetermined temperature,
In the low outside air temperature starting mode, when the compressor temperature detected by the compressor temperature detecting means after the first predetermined time elapses after starting the compressor at the first frequency is equal to or lower than a second predetermined temperature. The operating frequency of the compressor is changed to a second frequency lower than the first frequency, and the operating frequency of the compressor is set higher than the second frequency when a second predetermined time has elapsed after changing to the second frequency. An outdoor unit characterized by. The control means includes
When the second predetermined time has elapsed after changing to the second frequency,
When the compressor temperature detected by the compressor temperature detecting means is equal to or lower than a second predetermined temperature, the operating frequency of the compressor is set to the first frequency, and from that point in the low outside temperature starting mode Start control,
When the compressor temperature detected by the compressor temperature detecting means exceeds a second predetermined temperature, the operating frequency of the compressor is set to a third frequency higher than the first frequency. Item 4. The compressor according to Item 3.   The outdoor unit according to claim 3 or 4, wherein the second frequency is a lowest frequency operable by the compressor.

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