JP2016031182A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner which suppresses deterioration of heating capacity, in an operation for performing both defrosting and heating simultaneously by an outdoor heat exchanger connected in parallel.SOLUTION: An air conditioner includes: a main circuit in which a compressor, a four-way valve, an indoor heat exchanger, a decompression device and an outdoor heat exchanger having a first heat exchanger and a second heat exchanger connected in parallel are connected by refrigerant piping; a hot gas by-pass circuit for connecting a discharge side of the compressor and an inlet side at heating operation time of the first heat exchanger, and also, the discharge side of the compressor and the inlet side at heating operation time of the second heat exchanger; an outdoor fan; and control means for performing defrosting/heating operation for defrosting one of the first heat exchanger and the second heat exchanger, and using the other as an evaporator. The control means, at the defrosting/heating operation time, makes first rotational frequency of the outdoor fan from the start of the defrosting of the first heat exchanger before the elapse of first time higher than second rotational frequency of the outdoor fan from the start of the defrosting of the first heat exchanger after the elapse of the first time.SELECTED DRAWING: Figure 9

Description

  It relates to air conditioners.

  In Patent Document 1, a plurality of outdoor heat exchangers are connected in parallel, and a main circuit on-off valve is provided on the heating operation inlet side corresponding to the refrigerant circuit of each of the outdoor heat exchangers connected in parallel. A hot gas bypass circuit that is connected to the discharge side of each of the outdoor heat exchangers and the heating operation inlet side of the refrigerant circuit of each outdoor heat exchanger, the hot gas bypass circuit is provided with a bypass on-off valve corresponding to the refrigerant circuit of each outdoor heat exchanger, An air conditioner provided with a control device for controlling each component of an on-off valve and a refrigeration cycle, the control device, when starting defrosting of an outdoor heat exchanger during heating operation, the main circuit on-off valve and bypass A part of the on-off valve is controlled to open and close, and a part of the plurality of outdoor heat exchangers is defrosted and heated with other outdoor heat exchangers to perform a defrosting / heating operation. After repeating all of the outdoor heat exchangers in It has been described to be controlled to return.

  In addition, during the defrosting / heating operation, the rotation of the blower for the outdoor heat exchanger is more effective than during the heating operation in order to prevent an increase in the amount of hot gas used to melt the frost in the heat exchanger. Control is also described to reduce or stop the number.

JP 2009-281698 A

  However, since the air conditioner of Patent Document 1 lowers or stops the rotation speed of the fan of the outdoor heat exchanger during defrosting / heating operation compared to during heating operation, the heating capacity during defrosting / heating operation decreases. There was a problem.

  An object of this invention is to provide the air conditioner which suppresses the fall of heating capability, suppressing the calorie | heat amount of the hot gas taken away by external air at the time of a defrost and heating operation.

  An air conditioner of the present invention includes a compressor, a four-way valve, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger having a first heat exchanger and a second heat exchanger connected in parallel. The main circuit connected by the refrigerant pipe, the discharge side of the compressor and the inlet side during heating operation of the first heat exchanger, and the discharge side of the compressor and the inlet side during heating operation of the second heat exchanger A hot gas bypass circuit to be connected, an outdoor fan, and a control means for performing a defrosting / heating operation in which one of the first heat exchanger and the second heat exchanger is defrosted and the other is an evaporator. And the control means includes the first rotation number of the outdoor fan from the start of the defrosting of the first heat exchanger until the first time elapses during the defrosting / heating operation. The second rotational speed of the outdoor fan after the first time has elapsed from the start is set higher.

  ADVANTAGE OF THE INVENTION According to this invention, the air conditioner which suppresses the fall of heating capability can be provided, suppressing the calorie | heat amount of the hot gas taken away by external air at the time of a defrost and heating operation.

It is a block diagram of an air conditioner. It is a block diagram of a refrigerating cycle. It is a block diagram of a cooling cycle. It is a block diagram of a heating cycle. It is a block diagram of the defrosting / heating cycle which shows the flow of the refrigerant | coolant at the time of defrosting a 1st heat exchanger. It is a block diagram of the defrosting / heating cycle which shows the flow of the refrigerant | coolant at the time of defrosting a 2nd heat exchanger. It is the figure which showed the rotation speed of the outdoor fan at the time of defrosting and heating. It is the figure which showed the rotation speed of the outdoor fan at the time of defrosting and heating. It is the figure which showed the rotation speed of the outdoor fan at the time of defrosting and heating. It is the figure which showed the rotation speed of the outdoor fan at the time of defrosting and heating, and the temperature of a 1st heat exchanger.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the whole structure of an air conditioner is demonstrated using FIG.

  FIG. 1 is a configuration diagram of an air conditioner. The air conditioner 1 includes a refrigeration cycle, a blower, and a control system that controls them. The air conditioner 1 is a separate type air conditioner in which an indoor unit 2 and an outdoor unit 6 are connected via a refrigerant pipe 8, electrical wiring, signal wiring, and the like.

  FIG. 2 is a configuration diagram of the refrigeration cycle. The refrigeration cycle includes a compressor 75, a four-way valve 72, an outdoor heat exchanger 73, main circuit on / off valves 713a and 713b, a pressure reducing device 74, an indoor heat exchanger 33, and bypass on / off valves 715a and 715b, which are connected to a refrigerant pipe. Connected to each other.

  The refrigerant pipe includes a suction pipe 710, a discharge pipe 711, a use side gas pipe 712, a liquid pipe 713, a heat source side gas pipe 714, a hot gas bypass pipe 715, main circuit / bypass common pipes 716a and 716b, and the like.

  The indoor heat exchanger 33 is housed in the indoor unit 2, and the compressor 75, the four-way valve 72, the outdoor heat exchanger 73, the main circuit on / off valves 713 a and 713 b, the decompression device 74, and the bypass on / off valves 715 a and 715 b are provided in the outdoor unit 6. Stored.

  The four-way valve 72 is an example of a refrigerant flow path switching valve. The four-way valve 72 switches between a cooling cycle and a heating cycle.

  The cooling cycle is a cycle in which the refrigerant discharged from the compressor 75 through the discharge pipe 711 is guided to the outdoor heat exchanger 73 and the refrigerant from the indoor heat exchanger 33 is returned to the compressor 75. The heating cycle is a cycle in which the refrigerant discharged from the compressor 75 is guided to the indoor heat exchanger 33 and the refrigerant from the outdoor heat exchanger 73 is returned to the compressor 75 via the suction pipe 710 and the accumulator 76.

  The outdoor heat exchanger 73 constitutes a high-pressure side heat exchanger (condenser) during the cooling operation of the cooling cycle, and constitutes a low-pressure side heat exchanger (evaporator) during the heating operation of the heating cycle. The indoor heat exchanger 33 constitutes a high-pressure side heat exchanger (condenser) during the heating operation of the heating cycle, and constitutes a low-pressure side heat exchanger (evaporator) during the cooling operation of the cooling cycle.

  The outdoor heat exchanger 73 includes a refrigerant pipe and heat exchange fins, and a refrigerant circuit formed by the refrigerant pipe is divided into a plurality of pieces and connected in parallel. This refrigerant circuit is divided into a plurality of parts. The outdoor heat exchanger 73 includes a first heat exchanger 731 and a second heat exchanger 732. The configuration of the outdoor heat exchanger of the refrigerant circuit divided into a plurality of sections may be a structure in which each is separated (a structure in which the first and second heat exchangers are independent) or an integrated structure.

  Each of the outdoor heat exchangers 731 and 732 is connected to the decompression device 74 via main circuit on-off valves 713a and 713b. The compressor 75 branches from between the heat exchanger (the first heat exchanger 731 and the second heat exchanger 732) and the main circuit on / off valves 713a and 713b, and is connected to the compressor 75 via the bypass on / off valves 715a and 715b. A hot gas bypass circuit connected to the discharge pipe 711 by a hot gas bypass pipe 715 is provided.

  The decompression device 74 is provided between the outdoor heat exchanger 73 and the indoor heat exchanger 33, depressurizes the refrigerant from the outdoor heat exchanger 73 during cooling of the cooling cycle, and the indoor heat exchanger during heating operation of the heating cycle. The refrigerant from 33 is depressurized. In the present embodiment, the decompression device 74 is configured by an expansion valve whose throttle opening can be controlled, for example, an electric type.

  The main circuit on / off valves 713a and 713b and the bypass on / off valves 715a and 715b are composed of electromagnetic on / off valves, and open and close the refrigerant main circuit and the hot gas bypass circuit.

  The air blower in the air conditioner 1 includes an outdoor air blower 63 accommodated in the outdoor unit 6 and an indoor air blower 31 accommodated in the indoor unit 2.

  The outdoor blower 63 includes an outdoor fan 631 that causes outdoor air to flow through the outdoor heat exchanger 73, and an outdoor blower motor 633 that drives the outdoor fan 631. The indoor blower 31 includes an indoor fan 311 that causes indoor air to flow through the indoor heat exchanger 33, and an indoor blower motor 313 that drives the indoor fan 311. In this embodiment, an axial fan is used as the outdoor fan 631 and a cross fan is used as the indoor fan 311.

  The control system in the air conditioner 1 includes heat exchanger temperature detection sensors 811a, 811b and 812 and a control means 10. The heat exchanger temperature detection sensors 811a, 811b and 812 are heat exchanger temperature detection sensors 811a and 811b for detecting the outlet temperature of the heat exchangers 731 and 732 of the outdoor heat exchanger 73 during heating, and during reverse cycle defrosting. It is comprised from the heat exchanger temperature detection sensor 812 which detects the exit temperature of the outdoor heat exchanger 73 of this.

  The control means 10 includes a compressor 75, a four-way valve 72, an outdoor fan motor 633, an indoor fan motor 313, and a pressure reducing device 74 based on the detection results of the heat exchanger temperature detection sensors 811a, 811b and 812 and the user's operation command. The main circuit on / off valves 713a and 713b control the bypass on / off valves 715a and 715b. In the present embodiment, the control means 10 is shown as a single control device having a function of calculating and a control device having a function of controlling each device, but these may be configured separately. Alternatively, a control device having a function of controlling each device may be further divided.

  Next, the operation of the air conditioner 1 will be described with reference to FIGS.

  First, the cooling operation in the cooling cycle will be described with reference to FIG. FIG. 3 is a configuration diagram of the cooling cycle. When the air conditioner 1 is in cooling operation, the four-way valve 72 is switched as shown in FIG. 3, the main circuit on / off valves 713a and 713b are opened, and the bypass on / off valves 715a and 715b are closed to form a cooling operation cycle. At the same time, the compressor 75, the outdoor fan motor 633, and the indoor fan motor 313 are operated.

  The gas refrigerant sucked into the compressor 75 is compressed by the compressor 75, becomes a high-temperature and high-pressure gas refrigerant, flows in the direction of the solid line arrow in FIG. It enters into heat exchangers 731 and 732 of the vessel 73, is cooled and condensed by heat exchange with outdoor air, and becomes a refrigerant of liquid or gas-liquid mixture.

  Next, the refrigerant enters the decompression device 74 via the main circuit on-off valves 713a and 713b, expands due to decompression, and becomes a low-pressure gas-liquid mixed refrigerant. This gas-liquid mixed refrigerant flows in the direction of the broken arrow indicating the flow of the low-pressure refrigerant in FIG. 3, exits the outdoor unit 6, enters the indoor unit 2, enters the indoor heat exchanger 33 serving as an evaporator, and The inside of the room is cooled by heat exchange with itself, and is heated to return to the compressor 75 as a gas refrigerant.

  Next, the heating operation in the heating cycle will be described with reference to FIG. FIG. 4 is a block diagram of the heating cycle. When the heating operation is performed, the four-way valve 72 is switched as shown in FIG. 4, the main circuit on / off valves 713a and 713b are opened, the bypass on / off valves 715a and 715b are closed to form a heating operation cycle, and the compressor 75, The outdoor fan motor 633 and the indoor fan motor 313 are operated.

  The gas refrigerant sucked into the compressor 75 is compressed by the compressor 75, becomes a high-temperature and high-pressure gas refrigerant, flows in the direction of the solid line arrow in FIG. It enters into the vessel 33, is cooled and condensed by exchanging heat with room air, and becomes a refrigerant of liquid or gas-liquid mixture.

  The refrigerant that has condensed and entered the liquid or gas-liquid mixture exits the indoor unit 2 and enters the outdoor unit 6, enters the decompression device 74, expands due to decompression, and forms a low-pressure gas-liquid mixture refrigerant. Become. This gas-liquid mixed refrigerant flows in the direction of the broken-line arrow indicating the flow of the low-pressure refrigerant in FIG. 4, and through the main circuit on-off valves 713a and 713b, the heat exchanger 731 of the outdoor heat exchanger 73 serving as an evaporator, 732, heat is exchanged with outdoor air and heated to return to the compressor 75 as a gas refrigerant. By repeating the heating operation in the heating cycle described above, the heating operation is continued.

  During such a heating operation, the outdoor heat exchanger 73 is cooled to draw up heat from the outdoor air, and may become 0 ° C. or less and frost on the heat transfer surface. In particular, this phenomenon becomes prominent when the temperature of the outside air is low and the humidity is high, and the flow of outdoor air 631 is reduced by the flow of outdoor air being hindered by frost attached to the outdoor air flow surface. When the air volume of the outdoor fan 631 decreases, the temperature of the outdoor heat exchanger 73 further decreases, and frost is more likely to be formed. As a result, the amount of frost formation in the outdoor heat exchanger 73 continues to increase, the amount of heat pumped from the outdoor air by the air conditioner 1 decreases, the heating capacity also decreases, the room cannot be heated sufficiently, and the heating function is lost. Therefore, defrosting operation is necessary.

  Next, an operation for simultaneously performing defrosting and heating in the heating cycle (hereinafter referred to as “defrosting / heating operation”) will be described with reference to FIGS. FIG. 5 is a configuration diagram of a defrosting / heating cycle showing a flow of the refrigerant when the first heat exchanger is defrosted. FIG. 6 is a configuration diagram of a defrosting / heating cycle showing the flow of refrigerant when the second heat exchanger is defrosted.

  As described above, when the heating operation is performed under a condition where the temperature is low, the outdoor heat exchanger 73 is frosted, and the heating capacity is reduced due to the deterioration of the performance of the outdoor heat exchanger 73. Therefore, in this embodiment, when the temperature detected by the heat exchanger temperature detection sensor 812 is below a predetermined temperature and the heating operation in the heating cycle is performed for a predetermined time or more, the amount of frost formation is Defrosting / heating operation is performed assuming that the predetermined amount has been reached.

  In the defrosting / heating operation, as shown in FIG. 5, the four-way valve 72 has the same configuration (flow path) as in the heating operation, the first main circuit opening / closing valve 713a is closed, the second main circuit opening / closing valve 713b is opened, The first bypass on / off valve 715a is opened and the second bypass on / off valve 715b is closed to allow the first heat exchanger 731 in the outdoor heat exchanger 73 to function as a condenser and the second heat exchanger 732 to evaporate. It functions as a vessel and forms a defrosting / heating operation cycle in which defrosting and heating are performed simultaneously. At this time, as shown in FIG. 7, the second rotational speed F3 of the outdoor fan 631 (outdoor fan motor 633) during the defrosting / heating operation is set lower than the rotational speed F2 of the outdoor fan 631 during the heating operation.

  When the outside air temperature is equal to or lower than the predetermined temperature, the outdoor fan 631 during the defrosting / heating operation may be stopped as shown in FIG.

  Further, as shown in FIG. 8, the outdoor fan 631 during the defrosting / heating operation may be changed according to the outside air temperature.

  Here, the gas refrigerant sucked into the compressor 75 is compressed by the compressor 75, becomes a high-temperature and high-pressure gas refrigerant, is discharged to the discharge pipe 711, branches in the middle, and one refrigerant is the four-way valve 72. And the other refrigerant enters the hot gas bypass pipe 715.

  One refrigerant that has entered the four-way valve 72 flows in the direction of the solid arrow in FIG. 5, enters the indoor heat exchanger 33, exchanges heat with the indoor air, and is condensed to become a refrigerant of liquid or gas-liquid mixture. At this time, the room is heated. The refrigerant that has become the liquid or gas-liquid mixed refrigerant exits the indoor unit 2 and enters the outdoor unit 6 enters the decompression device 74, expands due to decompression, and becomes a low-pressure gas-liquid mixed refrigerant. This gas-liquid mixed refrigerant flows in the direction of the broken arrow indicating the flow of the low-pressure refrigerant in FIG. 5, and the second heat exchange of the outdoor heat exchanger 73 serving as an evaporator is performed via the second main circuit on-off valve 713b. It enters into the vessel 732 and is heated by exchanging heat with outdoor air, and returns to the compressor 75 as a gas refrigerant.

  On the other hand, the refrigerant that has entered the hot gas bypass pipe 715 flows in the direction of the solid line arrow in FIG. 5 and enters the first heat exchanger 731 of the outdoor heat exchanger 73 via the first bypass on-off valve 715a. Since the refrigerant that has entered the first heat exchanger 731 has a high temperature and high pressure, the frost adhering to the first heat exchanger 731 is melted and flows downward. The molten water that has flowed down flows into the second heat exchanger 732 located on the lower side that functions as an evaporator, and flows down while melting the frost on the second heat exchanger 732. When the outside air temperature is low, the molten water that has flowed down becomes lower in temperature as it flows down while melting the frost in the second heat exchanger 732, and finally freezes again.

  At this time, the molten water flows down while applying heat to the second heat exchanger 732, and the heat promotes vaporization of the refrigerant inside the second heat exchanger 732. That is, a part of the heat used for melting the frost in the first heat exchanger 731 on the upper side partially melts the frost on the second heat exchanger 732 on the lower side, and further the internal refrigerant It contributes to the vaporization of gas and is recovered, and the amount of heat of defrosting is used effectively.

  The refrigerant defrosted from the frost of the first heat exchanger 731 joins the refrigerant vaporized by the second heat exchanger 732 when it comes out of the first heat exchanger 731 and returns to the compressor 75. When the defrosting operation of the first heat exchanger 731 is performed for a predetermined time or when the heat exchanger temperature detection sensor 811a at the outlet of the first heat exchanger 731 rises to a predetermined temperature, the second heat exchanger 732 is subsequently removed. Do frost.

  To switch to defrosting of the second heat exchanger 732, the first main circuit on-off valve 713a is opened, the second main circuit on-off valve 713b is closed, the first bypass on-off valve 715a is closed, and the second bypass on-off valve 715b And the second heat exchanger 732 of the outdoor heat exchanger 73 functions as a condenser, and the first heat exchanger 731 functions as an evaporator to perform defrosting and heating simultaneously. Forms a defrosting / heating cycle. At this time, the outdoor air blowing motor 633 is operated or stopped at a low speed, and the indoor air blowing motor 313 controls the operation so that the blowing temperature can be maintained at a predetermined temperature or higher.

  Here, the flow of the refrigerant from the four-way valve 72 to the indoor heat exchanger 33 and decompressed by the decompression device 74 is the same as when the first heat exchanger 731 is defrosted. The refrigerant decompressed by the decompression device 74 flows in the direction of the broken line arrow in FIG. 6, and passes through the first main circuit on-off valve 713a to the first heat exchanger 731 of the outdoor heat exchanger 73 serving as an evaporator. It enters and is heated by exchanging heat with outdoor air, becomes a gas refrigerant and returns to the compressor 75 and returns to the compressor 75.

  The refrigerant that has entered the hot gas bypass pipe 715 flows in the direction of the solid line arrow in FIG. 6 and enters the second heat exchanger 732 of the outdoor heat exchanger 73 via the second bypass on-off valve 715b. Since the refrigerant that has entered the second heat exchanger 732 has a high temperature and a high pressure, the frost adhering to the second heat exchanger 732 is melted and allowed to flow downward. The molten water that has flowed down is discharged out of the outdoor unit 6 through the discharge port of the defrost water. The refrigerant defrosted from the second heat exchanger 732 joins the refrigerant vaporized by the first heat exchanger 731 when it leaves the second heat exchanger 732 and returns to the compressor 75. When the defrosting operation of the second heat exchanger 732 elapses for a predetermined time or when the heat exchanger temperature detection sensor 811b at the outlet of the second heat exchanger 732 rises to a predetermined temperature, the first main circuit on-off valve 713a The second main circuit opening / closing valve 713b is opened, the first bypass opening / closing valve 715a and the second bypass opening / closing valve 715b are closed, the defrosting / heating operation is terminated, and the operation immediately returns to the heating operation of FIG.

  Here, since the defrosted water that has flowed from the upper part passes through the lower part of the outdoor heat exchanger 73, defrosting with the melted water is performed. Therefore, when the defrosting of the outdoor heat exchanger 73 is performed, the defrosting is performed from the upper side in the order of the first heat exchanger 731 and the second heat exchanger 732. Thus, when the outdoor heat exchanger 73 is frosted and the frost amount reaches a predetermined amount that requires defrosting, the partial defrosting / heating operation is performed in order from the heat exchanger on the upper side. Since hot gas is allowed to flow through the refrigerant circuit on the upper side, frost adhering to the air-side heat transfer surface of the refrigerant circuit on the upper side of the outdoor heat exchanger 73 is melted and flows downward.

When the temperature of the molten water is high, the molten water touches the frost on the air side heat transfer surface of the heat exchanger on the lower side and further flows down while melting it with the sensible heat of the molten water itself. When the temperature of the flowing molten water falls to the melting point, the molten water flows down without further melting of the frost, and is cooled by the refrigerant in the lower refrigerant circuit flowing in the lower heat exchanger while flowing down. Solidify.
At this time, since the heat of solidification of the molten water warms the refrigerant in the lower refrigerant circuit, the amount of heat used to melt the frost is recovered by the heat exchanger on the upper side. When the defrosting / heating operation for defrosting the upper heat exchanger is completed, the defrosting / heating operation for defrosting the lower heat exchanger in order is started. Since hot gas from the compressor 75 is caused to flow through the refrigerant circuit that performs defrosting, the frost attached to the air-side heat transfer surface of the corresponding refrigerant circuit melts and flows downward.

  At this time, the heat exchanger immediately after the completion of the defrosting removes the frost that has hindered the heat transfer, so the heat transfer from the outside air to the refrigerant is performed smoothly, and the heat exchange capacity is restored. , Suppresses the decrease in indoor heating capacity. Thus, heating can be continued while suppressing a significant decrease in heating capacity even during defrosting / heating operation.

Further, during the defrosting / heating operation, the frosting amount of the heat exchanger below the defrosted heat exchanger may temporarily increase. However, since the defrosting / heating operation for defrosting the heat exchanger on the lower side is subsequently performed, the heat exchanger on the lower side is also defrosted. Therefore, the frost of the lower heat exchanger does not continue to increase due to the defrosting of the upper heat exchanger.
In this way, the total time required for the defrosting / heating operation can be shortened compared to the case where the reverse cycle defrosting operation is performed. Moreover, since the fall of the discharge temperature of the compressor 75 is suppressed at this time, the fall of heating capability can also be suppressed. For this reason, defrosting can be performed while heating the room, and the time required for the defrosting / heating operation can be shortened.

  In the present embodiment, a defrosting / heating operation in which the rotation speed of the outdoor fan of the refrigerant circuit divided into a plurality in the heating cycle of the air conditioner is changed will be described below.

  As shown in FIG. 7, when the rotation speed F1 of the outdoor fan 631 during the defrosting / heating operation is lower than the rotation speed F2 of the outdoor fan 631 during the heating operation, and the outside air temperature is lower than a predetermined value, Defrosting efficiency that suppresses the outside air flowing through the heat exchanger through which the hot gas being defrosted flows by stopping the fan 631, suppresses the amount of heat of the hot gas taken away by the outside air, and dissolves the frost of the heat exchanger by the hot gas Is increasing.

  However, during the defrosting / heating operation, during the defrosting of the first heat exchanger 731 of the outdoor heat exchanger 73, it is necessary for the refrigerant to continue to evaporate in the second heat exchanger 732 to ensure the heating capacity. . Therefore, if the rotational speed of the outdoor fan 631 is decreased as compared with that during the heating operation in order to increase the defrosting efficiency of the first heat exchanger 731, the evaporation amount of the second heat exchanger 732 that continues to evaporate is increased. Will be reduced. Therefore, the heating capacity at the time of defrosting / heating operation is reduced.

  By the way, when the defrosting of the first heat exchanger 731 is started, the heat transfer surface of the first heat exchanger 731 is covered with frost, and the heat cannot be sufficiently exchanged with the outside air. That is, even if the rotational speed of the outdoor fan 631 is not reduced, the frost has an action of blocking heat exchange between the first heat exchanger 731 and the outside air until the frost is melted. There is little effect on the outflow of hot gas heat.

  Therefore, as shown in FIG. 9, the air conditioner according to the present embodiment sets the first rotational speed F1 of the outdoor fan 631 from the start of defrosting of the first heat exchanger 731 until the first time elapses. It is higher than the second rotational speed F3 of the outdoor fan 631 after the first time t1 has elapsed from the start of defrosting of the first heat exchanger 731. That is, the outdoor heat exchanger 73 having the compressor 75, the four-way valve 72, the indoor heat exchanger 33, the decompression device 74, and the first heat exchanger 731 and the second heat exchanger 732 connected in parallel. Are connected by refrigerant piping, the discharge side of the compressor 75 and the inlet side during the heating operation of the first heat exchanger 731, and the heating operation of the discharge side of the compressor 75 and the second heat exchanger 732 A defrosting / defrosting circuit that defrosts one of the hot gas bypass circuit, the outdoor fan 631, the first heat exchanger 731 and the second heat exchanger 732 while connecting the hour inlet side to the other. And a control means 10 for performing a heating operation. The control means 10 includes a first outdoor fan 631 for a first time t1 from the start of the defrosting of the first heat exchanger 731 during the defrosting / heating operation. Of the first heat exchanger 731 from the start of defrosting for the first time t Higher than the second rotation speed F3 of the outdoor fan 631 after passage.

  According to such an air conditioner according to the present embodiment, it is possible to suppress a decrease in heating capacity while suppressing the amount of heat of hot gas taken by the outside air during the defrosting / heating operation.

Furthermore, as shown in FIG. 9, the control means 10 makes the first rotation speed F1 lower than the rotation speed F2 of the outdoor fan 631 during the heating operation.
Even at the start of defrosting of the first heat exchanger 731, heat exchange between the first heat exchanger 731 and the outside air is not completely interrupted by the frost. This is because it is necessary to reduce the influence of the heat flow of the gas.

  Further, the second rotational speed F3 of the outdoor fan 631 during the defrosting / heating operation may be set to zero.

  Moreover, you may make it reduce the 1st rotation speed F1 gradually or in steps with progress of a defrost / heating operation. As the defrosting progresses, the amount of hot gas heat flowing out to the outside air by forced convection also increases. Therefore, the first rotation speed F1 is lowered as the defrosting progresses, so that the rotation speed becomes more optimal. Can do.

  In the present embodiment, it is assumed that the first time t1 is set to a predetermined constant value. Instead, as shown in FIG. 10, the first heat exchange is started from Time 0 at the start of dehumidification / heating operation. The time until Time1 when the temperature of the heat exchanger temperature detection sensor 811a of the condenser 731 reaches a predetermined value Temp1 may be set as the first time t1. That is, a first temperature sensor (heat exchanger temperature detection sensor 811a) that detects the temperature of the first outdoor heat exchanger 731 is provided, and defrosting of the first outdoor heat exchanger 731 is started at the first time t1. The time from Time 0 to Time 1 when the temperature of the first temperature sensor (heat exchanger temperature detection sensor 811a) reaches a predetermined temperature Temp1 may be used.

  The heat exchanger temperature detection sensor 811a is installed at the outlet of the first heat exchanger 731, for example. According to such a configuration, the first time t1 can be changed in accordance with the progress of defrosting.

  Next, when the defrosting of the first heat exchanger 731 is completed, the defrosting of the second heat exchanger 732 is started, and heating is performed using the first heat exchanger 731 as an evaporator during the defrosting. We have the ability.

  Similarly to the start of defrosting of the first heat exchanger 731, the heat transfer surface of the second heat exchanger 732 is covered with frost at the start of defrosting of the second heat exchanger 732, and is sufficient with the outside air. Heat cannot be exchanged. Therefore, frost has the effect | action which interrupts | blocks the heat exchange with the 2nd heat exchanger 732 and external air.

  Therefore, in this embodiment, the rotational speed of the outdoor fan 631 is increased simultaneously with the start of defrosting of the second heat exchanger 732, and when the outdoor air temperature is lower than a predetermined value, the stopped outdoor fan 631 is driven. I am doing so. That is, the outdoor heat exchanger 73 having the compressor 75, the four-way valve 72, the indoor heat exchanger 33, the decompression device 74, and the first heat exchanger 731 and the second heat exchanger 732 connected in parallel. Are connected by refrigerant piping, the discharge side of the compressor 75 and the inlet side during the heating operation of the first heat exchanger 731, and the heating operation of the discharge side of the compressor 75 and the second heat exchanger 732 A defrosting / defrosting circuit that defrosts one of the hot gas bypass circuit, the outdoor fan 631, the first heat exchanger 731 and the second heat exchanger 732 while connecting the hour inlet side to the other. And a control unit 10 that performs a heating operation. The control unit 10 includes a first outdoor fan 631 that has a first defrost / heating operation until the second time t2 elapses from the start of the defrosting of the second heat exchanger 732. Of the second heat exchanger 732 from the start of defrosting for a second time t. Higher than the second rotation speed F3 of the outdoor fan 631 after passage.

  According to such an air conditioner according to the present embodiment, it is possible to suppress a decrease in heating capacity while suppressing the amount of heat of hot gas taken by the outside air during the defrosting / heating operation.

  Further, the first rotation speed F1 is set to a value lower than the rotation speed F2 of the outdoor fan 631 during the heating operation. Even at the start of defrosting of the second heat exchanger 732, the heat exchange between the second heat exchanger 732 and the outside air is not completely blocked by the frost. This is because it is necessary to reduce the influence of the heat flow of the gas.

  Further, the second rotational speed F3 of the outdoor fan 631 at the start of defrosting of the second heat exchanger 732 may be set to zero.

  Moreover, you may make it reduce the 1st rotation speed F1 gradually or in steps with progress of a defrost / heating operation. As the defrosting progresses, the amount of hot gas heat flowing out to the outside air by forced convection also increases. Therefore, the first rotation speed F1 is lowered as the defrosting progresses, so that the rotation speed becomes more optimal. Can do.

  In the present embodiment, it is assumed that the second time t2 is set to a predetermined constant value, but instead, the second heat exchanger 732 starts from the start of defrosting of the second heat exchanger 732. The time until the temperature of the heat exchanger temperature detection sensor 811b reaches a predetermined value may be set as the second time t2. That is, a second temperature sensor (heat exchanger temperature detection sensor 811b) that detects the temperature of the second outdoor heat exchanger 732 is provided, and defrosting of the second outdoor heat exchanger 732 is started at the second time t2. To the time from which the temperature of the second temperature sensor (heat exchanger temperature detection sensor 811b) reaches a predetermined temperature.

  The heat exchanger temperature detection sensor 811b is installed at the outlet of the second heat exchanger 732, for example. According to such a configuration, the second time t2 can be changed in accordance with the progress of defrosting.

  The outdoor heat exchanger 73 is composed of a plurality of stages, for example, four stages (a first heat exchanger 731, a second heat exchanger 732, a third heat exchanger 733, and a fourth heat exchanger 734). In addition to the first heat exchanger 731 and the second heat exchanger 732, the third heat exchanger 733 and the fourth heat exchanger 734 are also outdoors only for a predetermined time from the start of defrosting. The same effects as described above can be obtained by increasing or driving the rotational speed of the fan 631.

  Further, during the period during which the rotational speed of the outdoor fan 631 is increased or driven, the third heat exchanger 733 and the fourth heat exchanger 734 also have a predetermined time or the outlet of the heat exchanger from the start of defrosting. The same effect as described above can be obtained by increasing or driving the outdoor fan 631 only until the heat exchanger temperature detection sensors 811c and 8111d reach the predetermined value.

  Further, when the rotational speed of the outdoor fan 631 during the defrosting / heating operation is constant, when the outside air temperature approaches a predetermined value, the amount of heat of the hot gas taken away by the outside air increases. Therefore, as shown in FIG. 9, the rotation speed of the outdoor fan 631 is decreased stepwise depending on the outside air temperature, and the outside air temperature is stopped at a predetermined value, so that the amount of heat of the hot gas deprived by the outside air remains constant. Therefore, defrosting can be performed more efficiently.

  In this embodiment, the rotational speed of the outdoor fan 631 when the first heat exchanger 731 is defrosted and the rotational speed of the outdoor fan 631 when the second heat exchanger 732 is defrosted are the same. Different rotation speeds may be used.

DESCRIPTION OF SYMBOLS 10 ... Control means, 75 ... Compressor, 72 ... Four-way valve, 73 ... Outdoor heat exchanger, 74 ... Depressurization device, 33 ... Indoor heat exchanger, 631 ... Outdoor fan, 731 ... First heat exchanger, 732 ... Second heat exchanger, 811a ... heat exchanger temperature detection sensor, 811b ... heat exchanger temperature detection sensor, F1 ... first rotational speed of outdoor fan during defrosting / heating operation, F2 ... outdoor during heating operation Fan rotation speed, F3: second rotation speed of outdoor fan during defrosting / heating operation, t1 ... first time, t2 ... second time, Time0 ... dehumidification / heating operation start, Time1 ... first When the temperature of the heat exchanger temperature detection sensor of the heat exchanger reaches a predetermined value

Claims (5)

A compressor, a four-way valve, an indoor heat exchanger, a decompressor, and a main circuit in which an outdoor heat exchanger having a first heat exchanger and a second heat exchanger connected in parallel is connected by a refrigerant pipe ,
Hot gas bypass connecting the discharge side of the compressor and the inlet side during heating operation of the first heat exchanger, and the discharge side of the compressor and the inlet side during heating operation of the second heat exchanger Circuit,
With outdoor fans,
Control means for performing defrosting / heating operation using one of the first heat exchanger and the second heat exchanger as an evaporator while defrosting the other,
In the defrosting / heating operation, the control means determines the first rotational speed of the outdoor fan from the start of defrosting of the first heat exchanger until the first time elapses. The air conditioner which makes higher than the 2nd rotation speed of the said outdoor fan after the said 1st time has passed since the defrost start. A compressor, a four-way valve, an indoor heat exchanger, a decompressor, and a main circuit in which an outdoor heat exchanger having a first heat exchanger and a second heat exchanger connected in parallel is connected by a refrigerant pipe ,
Hot gas bypass connecting the discharge side of the compressor and the inlet side during heating operation of the first heat exchanger, and the discharge side of the compressor and the inlet side during heating operation of the second heat exchanger Circuit,
With outdoor fans,
Control means for performing defrosting / heating operation using one of the first heat exchanger and the second heat exchanger as an evaporator while defrosting one of the first heat exchanger and the second heat exchanger;
In the defrosting / heating operation, the control means determines the first rotational speed of the outdoor fan from the start of defrosting of the second heat exchanger until the second time elapses. The air conditioner which makes higher than the 2nd rotation speed of the said outdoor fan after the said 2nd time passes since a defrost start.   The air conditioner according to claim 1 or 2, wherein the control means makes the first rotation speed lower than the rotation speed during heating operation. A first temperature sensor for detecting the temperature of the first outdoor heat exchanger;
The said 1st time is time until the temperature of a said 1st temperature sensor turns into predetermined | prescribed temperature from the defrost start of a said 1st outdoor heat exchanger. Air conditioner. A second temperature sensor for detecting the temperature of the second outdoor heat exchanger;
The said 2nd time is a time from the defrost start of a said 2nd outdoor heat exchanger until the temperature of a said 2nd temperature sensor becomes predetermined | prescribed temperature, It is characterized by the above-mentioned. Air conditioner.