JP2012068001A - Outdoor unit and air conditioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outdoor unit or the like of an air conditioning device which includes a means having functionality equivalent to that of an electric heater to enhance serviceability or the like.SOLUTION: The outdoor unit connects a compressor 1 compressing and discharging an inhaled refrigerant, an outdoor heat exchanger 7 performing heat exchange between the refrigerant and open air, a four-way valve 2 for performing channel switching of the refrigerant, and discharging- and inhale-side piping of the compressor 1 to constitute a bypass circuit, and includes a bypass circuit comprising a bypass piping 9 supplying a heat quantity of the refrigerant discharged from the compressor 1 to an outdoor unit base part for loading instruments inside the outdoor unit 100, a capillary 10 used as a flow rate regulating means regulating a flow rate of efflux and influx of the refrigerant in the bypass piping 9, and an on-off valve 11 for bypass circuit, and a controller 110 controlling the flow rate regulating means passing the refrigerant discharged from the compressor 1 into the bypass piping 9.

Description

  The present invention relates to an outdoor unit or the like of an air conditioner. In particular, the present invention relates to an outdoor unit or the like that prevents freezing (freezing) of water in the outdoor unit base.

  For example, in an air conditioner using a refrigeration cycle (heat pump cycle), basically, an outdoor unit (heat source unit) having a compressor, an outdoor heat exchanger, etc., a flow rate control unit (expansion valve, etc.), an indoor unit side An indoor unit (load side unit) having a heat exchanger or the like is connected by a refrigerant pipe to constitute a refrigerant circuit for circulating the refrigerant. Then, in the indoor unit side heat exchanger, when the refrigerant evaporates and condenses, the heat, heat is released from the air in the air-conditioning target space to be heat exchanged, and the pressure, temperature, etc. related to the refrigerant in the refrigerant circuit are changed. Air conditioning is performed while changing.

  Here, the outdoor unit has an outdoor unit base part on which an indoor unit side heat exchanger or the like housed in the housing is placed. The indoor unit base is provided with a drain hole for discharging drain water or the like generated by defrosting or the like to the outside of the housing. Further, in the air conditioner, when performing heating operation, the outdoor unit side heat exchanger serves as an evaporator. For this reason, when the heating operation is performed when the temperature of outdoor air (hereinafter referred to as “outside air”) is low (low outside air), for example, drain water remaining in the indoor unit base portion freezes and closes the drain hole. If the drain hole is blocked, the drain water remaining in the outdoor unit base without being discharged will freeze further, causing root ice, etc., which obstructs the flow of air passing through the outdoor heat exchanger. Therefore, efficient heat exchange cannot be performed. Thus, an outdoor unit has been proposed in which an electric heater is installed around the drain hole and heated by energization to prevent freezing of water accumulated in the outdoor unit base (see, for example, Patent Document 1).

Japanese Patent No. 3882910 (FIG. 1)

  Originally, it is only necessary to install the above electric heater as a standard equipment in the outdoor unit base in advance, but not all models are used in an environment where the drain hole of the outdoor unit base is blocked. Absent. For this reason, in consideration of cost, the electric heater is often not standard equipment.

  And conventionally, the necessity of the electric heater of the air conditioner is determined locally, and only when it is determined necessary, it is installed locally.

  When an electric heater is installed on site, it is difficult to install because it is attached to the base of the outdoor unit avoiding the piping of the outdoor unit. For this reason, time is required for the attachment work (outdoor unit installation work). For this reason, considering serviceability, it is desirable to prevent freezing of water in the outdoor unit base without installing an electric heater on site.

  Therefore, the present invention is an air which can improve serviceability and the like while preventing freezing of water in the outdoor unit base by enabling heat supply (heat transfer) with a simple configuration instead of installing an electric heater. It aims at providing the outdoor unit etc. of a harmony device.

  The outdoor unit of the air conditioning apparatus of the present invention includes a compressor that compresses and discharges the sucked refrigerant, an outdoor heat exchanger that exchanges heat between the outside air and the refrigerant, a pipe on the discharge side of the compressor, and a suction side A flow rate for adjusting the flow rate of the refrigerant in the bypass pipe and the bypass pipe for supplying heat quantity of the refrigerant discharged from the compressor to the outdoor unit base for connecting the pipe and placing the equipment in the outdoor unit A bypass circuit having an adjustment unit and a control device for controlling the flow rate adjustment unit are provided.

  An outdoor unit of an air conditioner according to the present invention connects a discharge side and a suction side of a compressor 1 with a bypass pipe to form a bypass circuit, allows a high-temperature refrigerant to pass through the bypass pipe, and performs heat exchange to perform the outdoor unit. Since heat is supplied to the base, for example, in an environment where the outside air temperature is low, the water generated during defrosting during heating operation does not freeze, and the drain hole of the outdoor unit base is not blocked. Can drain water. For this reason, it can suppress that heating performance falls, without reducing the heat exchange efficiency of an outdoor heat exchanger, without storing water in an outdoor unit base part. And since it was made to pipe bypass piping instead of the electric heater attached to an outdoor unit base part in the field, the working time etc. which concern on installation can be shortened, and serviceability can be improved. In addition, since it is more flexible to arrange the bypass piping, heat can be efficiently supplied to a predetermined position of the outdoor unit base.

It is a figure showing the structure of the air conditioning apparatus of Embodiment 1 of this invention. It is the figure which represented the arrangement | positioning relationship of a bypass circuit from the upper side of the outdoor unit. It is a figure showing the flowchart of the anti-icing control process in this Embodiment 1. FIG. It is a figure showing the structure of the air conditioning apparatus of Embodiment 2 of this invention. It is the figure which represented the arrangement | positioning relationship of a 1st, 2nd bypass circuit from the upper side of the outdoor unit 100. FIG. It is a figure showing the flowchart of the anti-icing control process in this Embodiment 2. FIG. It is a figure showing the structure of the air conditioning apparatus of Embodiment 3 of this invention. It is a figure showing the flowchart of the anti-icing control process in this Embodiment 4. FIG. 10 is a diagram illustrating an arrangement relationship of bypass circuits in the fourth embodiment. It is a figure showing the structure of the bypass piping 50 which concerns on Embodiment 4. FIG. It is a figure showing the relationship between the distance through which a refrigerant | coolant flows, and piping temperature.

Embodiment 1 FIG.
The first embodiment relating to the present invention will be described below.
1 is a diagram showing the configuration of an air-conditioning apparatus according to Embodiment 1 of the present invention. In FIG. 1, the air conditioner (refrigerant circuit) which connected the outdoor unit 100 and the indoor unit 200 with refrigerant | coolant piping is comprised. An outdoor unit (heat source unit) 100 includes a compressor 1, a four-way valve 2, a gas operation valve 3, a liquid operation valve 6, an outdoor heat exchanger 7, an accumulator 8, a bypass pipe 9, a capillary 10, and a bypass circuit opening / closing valve 11. And a supercooling pipe 21, an inter-refrigerant heat exchanger 22, and a refrigerant regulating valve 23. In addition, an outdoor temperature sensor 30 serving as a temperature detection unit that detects an outdoor temperature and sends a detection signal to the control device 110 is provided.

  The compressor 1 compresses and discharges the sucked refrigerant. Here, the compressor 1 includes, for example, an inverter device, and the capacity of the compressor 1 (the amount of refrigerant sent out per unit time) is changed by arbitrarily changing the operation frequency based on an instruction from the control device 110. Can be changed finely. The four-way valve 2 switches the refrigerant flow between the cooling operation and the heating operation based on an instruction from the control device 110.

  The gas operation valve 3 controls the inflow / outflow of a gas (gas) -like refrigerant (including a gas-liquid two-phase refrigerant; hereinafter referred to as a gas refrigerant) to and from the outdoor unit 100. The liquid operation valve 6 controls the inflow and outflow of liquid refrigerant (including gas-liquid two-phase refrigerant; hereinafter referred to as liquid refrigerant) to the outdoor unit 100.

  The outdoor heat exchanger 7 performs heat exchange between the refrigerant and air (outdoor air). For example, it functions as an evaporator during heating operation, evaporating and evaporating the refrigerant. Moreover, it functions as a condenser during the cooling operation, and condenses and liquefies the refrigerant. Further, for example, a heat source side fan (not shown) is provided in order to efficiently exchange heat between the refrigerant and air in the heat source side heat exchanger 104. The accumulator 8 is a means for storing, for example, excess refrigerant. In particular, in the present embodiment, the refrigerant that has passed through the bypass pipe 9 that has become liquid (including a gas-liquid two-phase state) due to supply of heat to the outdoor unit base (heat exchange) flows.

  In the present embodiment, the bypass pipe 9, the capillary 10 serving as the flow rate adjusting means, and the bypass circuit on / off valve 11 are separated from the refrigerant circuit (hereinafter referred to as the main refrigerant circuit) configured with the indoor unit 200. The bypass circuit is formed. For example, the bypass pipe 9 connects, for example, the gas operation valve 3 and the accumulator 8 so that the refrigerant discharged from the compressor 1 during the heating operation flows to the accumulator 8 (suction side of the compressor 1). The capillary 10 serving as a bypass flow control means controls the flow rate of the refrigerant passing through the bypass circuit (bypass pipe 9). Here, the capillary 10 is used as the flow rate control means for bypassing, but the flow rate of the refrigerant may be controlled based on an instruction from the control device 110 using, for example, an electromagnetic valve. The bypass circuit opening / closing valve 11 controls passage and non-passage of the refrigerant in the bypass circuit based on an instruction from the control device 110. In the present embodiment, when a predetermined condition is satisfied during the heating operation, the refrigerant is opened so that the refrigerant passes through the bypass circuit, and during the cooling operation, the refrigerant is closed so that the refrigerant is not circulated through the bypass circuit. . Although the bypass circuit opening / closing valve 11 is used here, an electromagnetic valve or the like may be used, for example, so that the flow rate control means and the opening / closing valve are combined. Details of the bypass circuit will be described later.

  The supercooling pipe 21 is a pipe through which a refrigerant for supercooling the refrigerant is passed during cooling operation, for example. The inter-refrigerant heat exchanger 22 performs heat exchange between the refrigerant that has flowed out of the outdoor heat exchanger 7 and the refrigerant that passes through the supercooling pipe 21. The refrigerant adjustment valve 23 adjusts the flow rate and pressure of the refrigerant flowing through the subcooling pipe 21.

  In addition, the control device 110 performs control related to air conditioning by instructing each device constituting the air conditioning device. In the present embodiment, in particular, an anti-icing control process for preventing the drain hole in the outdoor unit base portion from being blocked by circulating the refrigerant in the bypass circuit is performed. Here, it is assumed that the control device 110 according to the present embodiment has a timer or the like (not shown) as time measuring means. Here, although it demonstrates as what has the control apparatus 110 mounted in the outdoor unit 100, it does not specifically limit about an installation position.

  On the other hand, the indoor unit 200 includes the indoor heat exchanger 4 and the electronic expansion valve 5. The indoor heat exchanger 4 performs heat exchange between the refrigerant and air. For example, it functions as a condenser during heating operation, and condenses and liquefies (or gas-liquid two-phase) the refrigerant. On the other hand, during the cooling operation, it functions as an evaporator, causing the refrigerant to evaporate by evaporating the heat of the air. The electronic expansion valve 5 is a pressure reducing means (pressure adjusting means) in the main refrigerant circuit that adjusts the pressure, flow rate, and the like of the refrigerant in the indoor heat exchanger 4 by changing the opening degree.

Here, the refrigerant to be circulated in the refrigerant circuit of the present embodiment is not particularly limited. For example, a single refrigerant such as R22, a non-azeotropic refrigerant mixture such as R407C, a pseudo azeotropic refrigerant such as R410A, a natural refrigerant such as CO ₂ , or the like can be used.

  Next, operation | movement of each apparatus which concerns on the main refrigerant circuit at the time of the heating operation in the air conditioning apparatus of FIG. 1 is demonstrated based on the flow of a refrigerant | coolant. The control device 110 performs operation control of the device. First, in the outdoor unit 100, the high-temperature and high-pressure gas (gas) refrigerant compressed and discharged by the compressor 1 passes through the four-way valve 2 and the gas operation valve 3 and flows out of the outdoor unit 100 to the indoor unit 200. Inflow.

  The refrigerant that has flowed into the indoor unit 200 passes through the indoor heat exchanger 4 that functions as a condenser. At this time, in the indoor heat exchanger 4, the refrigerant is condensed and liquefied by heat exchange, and heats the air in the air-conditioning target space, for example. Thereby, the air-conditioning target space is heated. The refrigerant that has passed through the indoor heat exchanger 4 is decompressed, for example, becomes a low-temperature and low-pressure two-phase refrigerant, flows out of the indoor unit 200, and flows into the outdoor unit 100.

  The refrigerant that has flowed into the outdoor unit 100 passes through the liquid operation valve 6 and flows into the outdoor heat exchanger 7 that functions as an evaporator. The refrigerant that has passed through the outdoor heat exchanger 7 is evaporated and vaporized (gasified) by exchanging heat with outdoor air, and is further sucked into the compressor 1 via the four-way valve 2 and the accumulator 8, and is described above. It circulates by being compressed and discharged. Here, during the heating operation, since the supercooling is not performed, the refrigerant adjustment valve 23 is closed so that the refrigerant does not pass through the supercooling pipe 21.

  In the basic heating operation, since it is not necessary to form a bypass circuit by flowing a refrigerant through the bypass pipe 9 (bypass circuit), the bypass circuit opening / closing valve 11 is closed.

  On the other hand, for example, when the heating operation is performed when the outside air temperature is low, the water generated at the time of defrosting freezes in the outdoor unit base part and closes the drain hole of the outdoor unit base part, and the outdoor heat exchanger 7 is Freezing may reduce heating performance. Therefore, in the air conditioner of Embodiment 1, a bypass circuit is formed in the outdoor unit 100 by the bypass pipe 9, the capillary 10 for adjusting the flow rate in the bypass circuit, and the bypass circuit opening / closing valve 11, and a high-temperature refrigerant is allowed to flow. To prevent the drain hole from freezing.

  Here, in this embodiment, the pipe diameter of the bypass pipe 9 is φ9.52 and the pipe length is 3000 [mm]. The capillary 10 has an outer diameter of 4.8, an inner diameter of 3.6, and a length of 600 [mm].

For example, in order to prevent the outdoor heat exchanger 7 from freezing based on the results of the base heater test so far, a heat amount of 150 [W] at a minimum can be supplied to the indoor unit base by heat exchange. I know it is necessary. Therefore, the supply of heat of 150 [W] (150 × 10 ⁻³ [kJ / s]) can be ensured at least by the refrigerant flowing through the bypass circuit.

For example, when heating operation is performed in the 10-horsepower compressor 1, the enthalpy difference ΔI between the refrigerant inlet and outlet of the bypass circuit is 15 [kJ / kg]. Therefore, the necessary refrigerant flow rate Gr [kg / h] satisfies the following equations (1) and (2).
Gr × ΔI × 1/3600 ≧ 150 × 10 ⁻³ (1)
Gr ≧ 150 × 10 ⁻³ / 15 × 3600 = 36 (2)

  Here, as the flow rate of the refrigerant circulating in the bypass circuit increases, a larger amount of heat can be supplied, so that the freezing of water in the indoor unit base is reliably prevented and the outdoor heat exchanger 7 is frozen. Can be prevented. On the other hand, in the main refrigerant circuit, since the flow rate of the refrigerant flowing through the indoor heat exchanger 4 is reduced, it is predicted that the heating capacity is lowered. Therefore, as described above, by providing the capillary 10 having the outer diameter φ4.8, the inner diameter φ3.6, and the length 600 [mm], the minimum refrigerant necessary for preventing freezing is circulated in the bypass circuit. ing.

  FIG. 2 is a diagram showing the arrangement relationship of the bypass circuit from the upper side of the outdoor unit 100. In the present embodiment, the bypass pipe 9 is arranged in the vicinity of the drain hole, and is fixed to the outdoor unit base portion by the fixing bracket, so that heat exchange can be efficiently performed and the drain hole can be prevented from being blocked. However, as long as a necessary amount of heat can be supplied to the outdoor unit base, the bypass pipe 9 does not need to be in close contact with the outdoor unit base.

  FIG. 3 is a diagram showing a flowchart of the anti-icing control process in the first embodiment. Next, in the present embodiment, control related to prevention of freezing performed by the control device 110 will be described. First, it is determined whether or not the operation mode is a heating operation (ST1). When it is determined that the heating operation is being performed, it is determined whether or not the outside air temperature is 3 ° C. or less based on a signal from the outdoor temperature sensor 30 (ST2), and the outside air temperature is 3 ° C. or less based on the timing of the timer. It is determined whether or not the state continues for 10 minutes (ST3).

  Here, for example, in the present embodiment, the outdoor air temperature is set to 3 ° C. or less because the amount of frost on the outdoor heat exchanger 7 increases when the outdoor air temperature is around 3 ° C. . If the amount of frost formation is large, there is a high possibility that water generated when defrosting is accumulated in the outdoor unit base, and icing may occur due to heat exchange of the outdoor heat exchanger 7. Further, if the outside air temperature is 0 ° C. or less, the amount of frost on the outdoor heat exchanger 7 is reduced. However, if the outdoor unit 100 is sprayed with snow or the like, for example, water in the outdoor unit base portion Is more likely to freeze. Also, the reason that the outside air temperature is 10 minutes or less is that from the results of the base heater test so far, when the temperature is 10 minutes or more, the freezing of water in the outdoor unit base proceeds and the drain hole tends to be blocked. This is because. In consideration of the above, in the present embodiment, it is determined whether or not the state where the outside air temperature is 3 ° C. or less continues for 10 minutes. However, the specific values of the outside air temperature and time as the determination conditions are not particularly limited. Basically, the setting can be changed based on the environment, the size of the outdoor unit 100, and the like. In addition, although the outside air temperature is used as the determination condition here, the determination may be performed based on a condition related to another temperature.

  As a result of the determination, if the above conditions are not satisfied, it can be considered that the drain hole of the outdoor unit base is not blocked, and the operation as it is (the heating operation in which only the main refrigerant circuit circulates the refrigerant) is continued. On the other hand, when the condition is satisfied, the bypass circuit opening / closing valve 11 is opened (opened) so that the refrigerant can pass through the bypass pipe 9, and a bypass circuit is formed (ST4). By forming the bypass circuit, heat exchange is performed between the high-temperature refrigerant discharged from the compressor 1 via the bypass pipe 9 and the outdoor unit base, and the heat amount of the refrigerant is supplied to the outdoor unit base. It is possible to prevent water from freezing in the outdoor unit base.

  Then, after forming the bypass circuit, it is determined that the operation of the air conditioner is stopped (ST5), or whether the outside air temperature is higher than 3 ° C. based on the signal from the outdoor temperature sensor 30 during the operation. If it is determined (ST6) and it is determined that the outside air temperature is higher than 3 ° C. for 10 minutes (ST7), the bypass circuit opening / closing valve 11 is closed (closed) and the refrigerant does not flow into the bypass pipe 9. (ST8).

  As described above, in the outdoor unit 100 of the air-conditioning apparatus according to Embodiment 1, the gas operation valve 3 and the compressor on the discharge side of the compressor 1 are used instead of the electric heater attached to the outdoor unit base in the field. A bypass pipe 9 is connected to the accumulator 8 on the suction side of 1 to form a bypass circuit. For example, during a heating operation in which the outdoor heat exchanger 7 functions as an evaporator, a predetermined condition is satisfied. Since the bypass circuit opening / closing valve 11 is opened and the flow rate is adjusted by the capillary 10, the high-temperature refrigerant is passed through the bypass pipe 9, and the heat quantity is supplied to the outdoor unit base by heat exchange. For example, in an environment where the outside air temperature is low, the water generated during defrosting during heating operation does not freeze, does not block the drain hole of the outdoor unit base, and discharges water outside the outdoor unit 1 It can be. For this reason, it can suppress that heating performance falls, without reducing the heat exchange efficiency of the outdoor heat exchanger 7, without storing water in an outdoor unit base part. By allowing the refrigerant that has flowed out of the bypass pipe 9 to flow through the accumulator 8, the reliability can be improved without the compressor 1 sucking in the liquid refrigerant.

  In addition, since the bypass pipe 9 is provided, work time and the like related to installation can be shortened, and serviceability can be improved. Since the bypass pipe 9 has a higher degree of freedom in arrangement than the later installation of the electric heater, the amount of heat can be supplied to a predetermined position of the outdoor unit base. And since the calorie | heat amount of the refrigerant | coolant which the compressor 1 discharged instead of an electric heater is supplied, required calorie | heat amount can be supplied quickly and efficiently rather than the calorie | heat amount supply using an electric heater.

Embodiment 2. FIG.
The second embodiment relating to the present invention will be described below.
FIG. 4 is a diagram showing the configuration of the air-conditioning apparatus according to Embodiment 2 of the present invention. In the first embodiment described above, the refrigerant discharged from the compressor 1 is caused to flow through the accumulator 8 (the suction side of the compressor 1) by the bypass circuit to prevent freezing of water in the outdoor unit base. Here, in the vicinity of the refrigerant outlet from the bypass pipe 9, the amount of heat exchange decreases, so in some cases, the necessary amount of heat cannot be supplied to the outdoor unit base, and the drain hole is not sufficient for heat exchange. May remain blocked.

  Therefore, in the outdoor unit of the air conditioner according to the second embodiment, a plurality of bypass circuits are configured, and for example, the refrigerant flowing in each bypass circuit flows in the opposite direction so that the necessary amount of heat is supplied near each drain hole. Is something to do.

  In the air conditioner of FIG. 4, devices and the like having the same reference numerals as those in FIG. 1 perform the same operations and functions as the operations and functions described in the first embodiment. Here, in the present embodiment, a bypass circuit formed by the bypass pipe 9 or the like is a first bypass circuit. The bypass pipe 12 is a pipe for forming a second bypass circuit, similarly to the bypass pipe 9. The capillary 13 adjusts the flow rate of the refrigerant passing through the bypass circuit (bypass pipe 12). Further, the bypass circuit opening / closing valve 14 controls whether or not refrigerant circulation is performed in the bypass circuit based on an instruction from the control device 110.

  FIG. 5 is a diagram showing the arrangement relationship between the first bypass circuit and the second bypass circuit from the upper side of the outdoor unit 100. In the present embodiment, the bypass pipes 9 and 12 are divided into two directions and arranged on the indoor unit base.

  FIG. 6 is a flowchart illustrating the anti-icing control process according to the second embodiment. Next, a description will be given of the control related to the prevention of water icing in the outdoor unit base portion in the present embodiment where the control device 110 performs processing. First, as described in the first embodiment, the operation mode and the outside air temperature are determined, and it is determined whether the operation mode is the heating operation and whether the outside air temperature is 3 ° C. or lower is detected continuously for 10 minutes. (ST11-ST13).

  If the condition is not satisfied as a result of the determination, the operation is continued as it is because the drain hole of the outdoor unit base will not be blocked. On the other hand, if it is determined that the condition is satisfied, the bypass circuit opening / closing valves 11 and 14 are opened to allow the refrigerant to pass through the bypass pipes 9 and 12, thereby forming the first and second bypass circuits (ST14). By forming the two bypass circuits, the amount of heat generated by the high-temperature refrigerant discharged from the compressor 1 can be supplied to the outdoor unit base, and water can be prevented from freezing in the outdoor unit base.

  If it is determined that after the bypass circuit is formed, the operation of the air conditioner is stopped or the outside air temperature is higher than 3 ° C. during the operation is detected for 10 minutes continuously (ST15 to ST17), the bypass circuit opening / closing valve 11 , 14 are closed to prevent the refrigerant from flowing into the bypass pipes 9 and 12, and the refrigerant is circulated in the refrigerant circuit (ST18).

  As described above, in the outdoor unit 100 of the air-conditioning apparatus according to Embodiment 2, the heat quantity can be supplied from a plurality of positions of the outdoor unit base by configuring a plurality of bypass circuits. For this reason, for example, in each bypass circuit, a decrease in the amount of heat supplied in the vicinity of the refrigerant outlet (accumulator 8) can be compensated by heat supply in the other bypass circuits. For this reason, the bias | inclination of the calorie | heat amount supplied in the whole outdoor unit base part can be prevented.

Embodiment 3 FIG.
A third embodiment relating to the present invention will be described below.
FIG. 7 is a diagram illustrating the configuration of the air-conditioning apparatus according to Embodiment 3 of the present invention. In the first and second embodiments described above, whether or not the bypass circuit opening and closing valves 11 and 14 are closed to stop the refrigerant circulation to the bypass circuit is determined based on the outside air temperature. Here, since the temperature of the outdoor unit base is indirectly determined based on the outside air temperature, the refrigerant circulation in the bypass circuit is actually stopped even though the water in the outdoor unit base is frozen. there is a possibility. For this reason, it is possible to improve the accuracy of the determination and more reliably prevent icing than the determination based on the indirect outside air temperature.

  Therefore, in the present embodiment, a temperature sensor (refrigerant temperature detection means) is installed at each of the refrigerant inlets and outlets of the bypass pipes 9 and 12, and the bypass circuit is opened and closed based on the temperature difference between the refrigerant inlet and the refrigerant outlet. It is determined whether or not the valves 11 and 14 are closed, and the accuracy of preventing the freezing of the outdoor unit base is improved.

  As shown in FIG. 7, a first circuit inflow side temperature sensor 15 for detecting the temperature of the refrigerant inlet portion of the first bypass circuit is provided. Moreover, the 1st circuit outflow side temperature sensor 16 for detecting the temperature of a refrigerant | coolant outflow port part is provided. Similarly, a second circuit inflow side temperature sensor 17 for detecting the temperature of the refrigerant inlet portion of the second bypass circuit and a second circuit outflow side temperature sensor 18 for detecting the temperature of the refrigerant outlet portion are provided.

  FIG. 8 is a diagram illustrating a flowchart of an anti-icing control process in the air-conditioning apparatus according to the third embodiment. As described in the first embodiment, the operation mode and the outside air temperature are determined, and it is determined whether the operation mode is the heating operation and whether the outside temperature is 3 ° C. or lower is continuously detected for 10 minutes (ST21). ~ ST23).

  If it is determined that the condition is not satisfied, the operation is continued as it is. On the other hand, if it is determined that the condition is satisfied, the bypass circuit opening / closing valve 11 is opened to form the first bypass circuit, and the bypass circuit opening / closing valve 14 is opened to form the second bypass circuit (ST24).

  Next, it is determined whether the heating operation is continued or stopped (ST25). If it is determined that the heating operation is to be stopped, the bypass circuit opening / closing valves 11 and 14 are both closed, and the refrigerant circulation in the bypass circuit is stopped (ST26).

  If it is determined that the operation is to be continued, it is determined whether the temperature difference ΔT1 between the temperature sensor 15 and the temperature sensor 16 in the first bypass circuit is 15 degrees (15 ° C.) or less for 10 minutes (ST27). Similarly, it is determined whether or not the state where the temperature difference ΔT2 between the temperature sensor 17 and the temperature sensor 18 in the second bypass circuit is 15 degrees (15 ° C.) or less continues for 10 minutes (ST28). Here, the order in which ST27 and ST28 are determined does not matter.

  If it is determined in ST27 and ST28 that the condition is not satisfied, the operation is continued as it is. On the other hand, if it is determined in ST27 that the condition is satisfied, the bypass circuit opening / closing valve 11 is closed to prevent the refrigerant from passing through the bypass pipe 9 (ST29).

  Similarly, when it is determined that the condition is satisfied in ST28, the bypass circuit opening / closing valve 14 is closed to prevent the refrigerant from passing through the bypass pipe 12 (ST30).

  As described above, in the outdoor unit 100 of the air conditioner according to Embodiment 3, the temperature sensors 15, 16, 17, and 18 are installed near the refrigerant inflow / outflow of the bypass pipes 9 and 12, and the inflow / outflow into the respective bypass pipes. Since whether or not to close the bypass circuit opening / closing valves 11 and 14 is determined based on the temperature difference of the refrigerant to be used, such as whether or not the outdoor unit base is frozen based on the temperature closer to the outdoor unit base It is possible to improve the determination accuracy of the state confirmation.

Embodiment 4 FIG.
Embodiment 4 relating to the present invention will be described below.
FIG. 9 is a diagram showing the arrangement relationship of the bypass circuit in the fourth embodiment of the present invention from the upper side of the outdoor unit 100. For example, in Embodiment 2 described above, a plurality of bypass circuits are configured to increase the amount of heat exchange. However, in the configuration according to the second embodiment, the capillaries 13 and the bypass circuit opening / closing valves 14 are provided in each bypass circuit, so it is necessary to consider, for example, an increase in parts cost and securing of an arrangement space. Therefore, in the present embodiment, a part of the bypass pipe has a double pipe structure so that the supply of heat in the vicinity of the accumulator 8 serving as the refrigerant outlet of the bypass pipe is increased (the amount of heat exchange is increased). To do.

  FIG. 10 is a diagram illustrating the structure of the bypass pipe 50 according to the fourth embodiment. The bypass pipe 50 has a double pipe structure as shown in FIG. The pipe diameter of the double pipe is φ15.88 [mm] for the outer pipe (hereinafter referred to as the outer pipe), and φ9.52 [mm] for the inner pipe (hereinafter referred to as the inner pipe). The bypass pipe arranged around the accumulator 8 is made to have a double pipe structure. Then, the refrigerant flowing through the outer pipe and the refrigerant flowing through the inner pipe are opposed to each other.

  FIG. 11 is a diagram illustrating the relationship between the refrigerant flow distance and the piping temperature. The refrigerant flowing in from the discharge side of the compressor 1 passes separately on the outer tube side and the inner tube side. The refrigerant on the outer tube side supplies (dissipates) heat to the periphery of the accumulator 8, and also supplies it to the refrigerant on the inner tube side. The piping temperature around the accumulator 8 can be increased (T1 → T2 in FIG. 11), so that the efficiency of heat exchange can be increased and the cost increase can be suppressed.

  As described above, in the outdoor unit 100 of the air conditioner according to the fourth embodiment, the bypass pipe 50 has a double pipe structure, so that heat can be supplied from a plurality of positions of the outdoor unit base. It becomes possible to further improve the efficiency of heat exchange. At this time, the number of capillaries and bypass circuit opening / closing valves can be reduced, and the cost can be reduced. Moreover, since it is not necessary to secure these installation spaces, the freedom degree of piping can also be raised.

  Here, although the bypass circuit of this embodiment has been described as an alternative to the two bypass circuits in the second embodiment, the present invention is not limited to this. For example, as in the second embodiment, a plurality of bypass circuits configured by using the bypass pipe 50 having at least a part of a double pipe structure as in the present embodiment may be provided.

Embodiment 5 FIG.
In the above-described embodiment, the bypass circuit including the bypass pipe 9 and the like is configured as a substitute for the electric heater that is installed in the field in order to supply heat to the outdoor unit base in a low outside air environment. However, the use of the bypass circuit is not limited to this. For example, normally, when defrosting (defrosting), heat is supplied to the outdoor heat exchanger or the like to melt frost, but it can be used as an apparatus for supplying heat to the outdoor unit base. .

  Although the above-mentioned embodiment explained the outdoor unit of an air harmony device, it is applicable also to other refrigeration cycle (heat pump) devices, such as a hot-water supply system in which outdoor heat exchanger 7 functions as an evaporator, for example. it can.

  1 Compressor, 2 Four-way valve, 3 Gas operation valve, 4 Indoor heat exchanger, 5 Electronic expansion valve, 6 Liquid operation valve, 7 Outdoor heat exchanger, 8 Accumulator, 9, 12, 50 Bypass piping, 10, 13 Capillary, 11, 14 Bypass circuit opening / closing valve, 15 First circuit inflow side temperature sensor, 16 First circuit outflow side temperature sensor, 17 Second circuit inflow side temperature sensor, 18 Second circuit outflow side temperature sensor, 21 Piping for cooling, 22 Heat exchanger between refrigerants, 23 Refrigerant adjustment valve, 30 Outdoor temperature sensor, 100 Outdoor unit, 110 Control device, 200 Indoor unit.

Claims (7)

A compressor for compressing and discharging the sucked refrigerant;
An outdoor heat exchanger for exchanging heat between the outside air and the refrigerant;
Connecting the discharge-side piping and the suction-side piping of the compressor, and supplying the heat quantity of the refrigerant discharged from the compressor to the outdoor unit base for mounting the equipment in the outdoor unit A bypass circuit having a bypass pipe and a flow rate adjusting means for adjusting a flow rate of the refrigerant in the bypass pipe;
An outdoor unit comprising: a control device that controls the flow rate adjusting means. It further comprises an outside air temperature detecting means for detecting the outside air temperature,
The control device determines whether or not a state in which a temperature related to detection by the outside air temperature detecting means is a predetermined temperature or lower continues for a predetermined time when the outdoor heat exchanger functions as an evaporator. 2. The outdoor unit according to claim 1, wherein the outdoor unit is controlled to control the flow rate adjusting means to pass the refrigerant in the bypass pipe. An accumulator for storing a liquid refrigerant on the suction side of the compressor;
The outdoor unit according to claim 1, wherein the bypass pipe is connected so that the refrigerant flowing out of the bypass pipe passes through the accumulator. Refrigerant temperature detection means for detecting the temperature of the refrigerant inlet and the refrigerant outlet in the bypass pipe,
The said control apparatus judges whether the refrigerant | coolant passage of the said bypass piping is stopped based on the temperature difference of the said refrigerant | coolant inflow port which concerns on the detection of the said temperature detection means, and the said refrigerant | coolant outflow port. Item 4. The outdoor unit according to any one of Items 1 to 3.   The outdoor unit according to any one of claims 1 to 4, further comprising a plurality of bypass circuits so that the amount of heat of the refrigerant can be supplied from a plurality of positions of the outdoor unit base.   The outdoor unit according to any one of claims 1 to 5, wherein at least a part of the bypass pipe has a double pipe structure including an outer pipe and an inner pipe. Pipe connection between the outdoor unit according to any one of claims 1 to 6 and an indoor unit having a pressure adjusting means for controlling the pressure of the refrigerant and an indoor side heat exchanger for performing heat exchange with the air in the air-conditioning target space An air conditioner characterized by: