JP2018091540A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly perform cooling operation when an external temperature is low in a manner that keeps a balance between a heat exchange amount of a condenser and the same of an evaporator.SOLUTION: An air conditioner comprises: an auxiliary heat exchanger 203b which is installed on a connection flow passage, in a refrigerant circuit 20, connecting a first connection point X between an outdoor heat exchanger 203a and a main expander 204 and a second connection point Y between an indoor heat exchanger 205 and a compressor 201; a first expansion valve 206 which is installed at an upstream side of the auxiliary heat exchanger 203b on the connection flow passage; and a second expansion valve 207 which is installed, in the refrigerant circuit 20, between the second connection point Y and the indoor heat exchanger 205. The first expansion valve 206 and the second expansion valve 207 cause evaporation pressure of the auxiliary heat exchanger 203b to differ from the same of the indoor heat exchanger 205.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an air conditioner.

  There is an air conditioner having a refrigeration cycle in which refrigerant circulates through a refrigerant circuit in which a compressor, a four-way switching valve, an outdoor heat exchanger, a main throttle unit, and an indoor heat exchanger are sequentially connected. In such an air conditioning apparatus, different air conditioning operations such as a cooling operation and a heating operation are performed by switching the refrigerant circulation direction using, for example, a four-way switching valve.

  By the way, in the cooling operation at the low outside air temperature, the heat exchange capacity of the outdoor heat exchanger becomes excessive with respect to the heat exchange capacity of the indoor heat exchanger. If it does so, icing will arise on the surface of an indoor side heat exchanger, a cooling operation will be hindered, or a difference will not arise between a condensation pressure and evaporation pressure, but a malfunction will arise in a compressor.

  Here, what is shown in Patent Document 1 is considered for the purpose of smoothly performing the cooling operation at the low outside air temperature. This air conditioner divides an outdoor heat exchanger, uses one divided outdoor heat exchanger as a condenser, and uses the other divided outdoor heat exchanger as an evaporator.

  However, the air conditioner of Patent Document 1 cannot individually control the evaporation pressure of the indoor heat exchanger and the evaporation pressure of the other divided outdoor heat exchanger. Then, when the outdoor air temperature is lower than the room temperature, such as a temperature lower than the freezing point, when the evaporation pressure is adjusted to the indoor heat exchanger, the other outdoor heat exchanger does not function as an evaporator, or the outdoor heat exchange. When the evaporation pressure is adjusted to the condenser, the problem of freezing on the surface of the indoor heat exchanger occurs.

JP 2003-28530 A

  Therefore, the present invention has been made to solve the above-mentioned problems all at once, and in the cooling operation at the time of low outside air temperature (for example, the condition where the outside air temperature is lower than the room temperature), the heat exchange amount of the condenser The main object is to provide an air conditioner that can balance the heat exchange amount of the evaporator and perform a smooth cooling operation.

  That is, the air conditioner according to the present invention is an air conditioner having a refrigerant circuit in which a compressor, an outdoor heat exchanger, a main throttle unit, and an indoor heat exchanger are connected in this order, and the outdoor circuit in the refrigerant circuit An auxiliary heat exchanger provided in a connection flow path connecting the first connection point between the heat exchanger and the main throttle and the second connection point between the indoor heat exchanger and the compressor; A first throttle portion provided on the upstream side of the auxiliary heat exchanger in the connection flow path; and a second throttle portion provided between the second connection point and the indoor heat exchanger in the refrigerant circuit. And the first throttle part and the second throttle part are configured so that the evaporation pressure of the auxiliary heat exchanger is different from the evaporation pressure of the indoor heat exchanger.

  If it is such, since the evaporation pressure of the auxiliary heat exchanger and the evaporation pressure of the indoor heat exchanger are different, the outside air temperature is lower than the room temperature, such as a temperature lower than the freezing point, The auxiliary heat exchanger can function as an evaporator, and freezing such as freezing on the surface of the indoor heat exchanger can be prevented. Therefore, even in a cooling operation at a low outside air temperature (for example, under a condition where the outside air temperature is lower than the room temperature), the cooling operation is smoothly performed by balancing the heat exchange amount of the condenser and the heat exchange amount of the evaporator. be able to. Specifically, for example, cooling under a low outside air temperature condition of −5 ° C. or lower is possible. It also prevents fluctuations in the room temperature due to the thermo-off that occurs frequently due to the excessive cooling capacity that occurs at low outside temperatures (the room temperature reaches the set temperature, the outdoor unit stops and the room cooling operation stops). can do. In addition, in the configuration of the above-mentioned Patent Document 1, an additional solenoid valve is required for switching the refrigerant circuit, and the price increase of the refrigerant circuit and the control circuit becomes a problem. There is no worry, and the cost of the refrigerant circuit and the control circuit can be reduced.

  When the refrigerant circuit has a four-way valve for switching the refrigerant flow direction during cooling operation and the refrigerant flow during heating operation, the second connection point is the four-way valve in the refrigerant circuit and It may be provided between the compressors. In this configuration, the second throttle portion branches from a pipe where the refrigerant returns from the four-way valve to the compressor side in the refrigerant circuit and joins the second connection point, or the refrigerant circuit. It is conceivable that it is provided in a branch flow path that branches from a pipe connecting the four-way valve and the indoor heat exchanger and joins the second connection point.

  As a specific embodiment for controlling the evaporation pressure of the auxiliary heat exchanger, the first throttle part and the second throttle part are expansion valves, and a control device for controlling the valve opening degree of the expansion valve However, it is desirable to control the valve opening degree of the first and second throttle portions according to the outside air temperature so that the evaporation pressure of the auxiliary heat exchanger is different from the evaporation pressure of the indoor heat exchanger.

The specific control contents are as follows.
(1) An outside temperature sensor that measures the outside temperature and a suction pressure sensor that measures the suction pressure of the refrigerant into the compressor, and the control device uses the auxiliary temperature from the outside temperature obtained by the outside temperature sensor. The evaporation pressure of the heat exchanger is determined, the suction pressure obtained by the suction pressure sensor is acquired, and the valve opening degrees of the first and second throttle parts are feedback-controlled.
(2) An outside air temperature sensor that measures an outside air temperature and an intake temperature sensor that measures an intake temperature of the refrigerant into the compressor, and the control device uses the auxiliary temperature from the outside air temperature obtained by the outside air temperature sensor. The evaporation pressure of the heat exchanger is determined, the suction temperature obtained by the suction temperature sensor is acquired, and the valve opening degrees of the first and second throttle parts are feedback-controlled.
(3) The control device performs feedback control of the valve openings of the first and second throttle portions so that the degree of superheat of the suction pipe of the compressor is constant.

  In order to configure without providing an auxiliary heat exchanger outside, and to easily balance the heat exchange amount of the condenser and the heat exchange amount of the evaporator, the outdoor heat exchanger is divided into a plurality of parts, The divided outdoor heat exchanger is preferably configured as the auxiliary heat exchanger.

  In order to prevent the piping configuration in the outdoor unit from becoming complicated due to the division of the outdoor heat exchanger, it is desirable that the auxiliary heat exchanger is configured by an indoor heat exchanger of another air conditioner.

  The second throttle part may be constituted by a capillary.

An outdoor unit having the compressor and the outdoor heat exchanger; an indoor unit having the main throttle unit and the indoor heat exchanger; and a connecting pipe connecting the outdoor unit and the indoor unit, the auxiliary heat It is desirable that the exchanger, the first throttle portion, and the second throttle portion are provided in an auxiliary unit that is externally attached to the connection pipe.
If it is this, the adjustment function of the heat exchange amount of the outdoor heat exchanger and the heat exchange amount of the indoor heat exchanger in the cooling operation at the low outside air temperature can be added to the existing air conditioner.

  According to the present invention, since the evaporating pressure of the auxiliary heat exchanger and the evaporating pressure of the indoor heat exchanger are made different, the cooling operation at the time of low outside air temperature (for example, the condition that the outside air temperature is lower than the room temperature). Therefore, the cooling operation can be smoothly performed by balancing the heat exchange amount of the condenser and the heat exchange amount of the evaporator.

It is a figure which shows the flow of the refrigerant | coolant at the time of normal cooling operation in 1st Embodiment. It is a figure which shows the flow of the refrigerant | coolant at the time of the heating operation in the embodiment. It is a figure which shows the flow of the refrigerant | coolant at the time of the air_conditionaing | cooling operation of the low external temperature in the embodiment. It is a schematic diagram which shows the structure of the air conditioner in 2nd Embodiment. It is a schematic diagram which shows the modification of the air conditioner in 2nd Embodiment. It is a schematic diagram which shows the structure of the air conditioner in deformation | transformation embodiment.

<First Embodiment>
A first embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the air conditioner 100 according to the first embodiment includes an outdoor unit 10 installed outside a building, an indoor unit 11 installed in the building, and the outdoor unit 10 and the indoor unit 11 as refrigerant. A refrigerant circuit 20 connected by piping, an air conditioner outdoor control unit 30 and an air conditioner indoor control unit 31 which are control devices that control the outdoor unit 10 and the indoor unit 11 and the like to perform an air conditioning operation. I have. The air conditioner outdoor unit control unit 30 and the air conditioner room control unit 31 control each unit of the air conditioner 100. Although the air conditioner outdoor unit control unit 30, the air conditioner indoor control unit 31, and each unit of the indoor unit 11 and the outdoor unit 10 are connected, the connection description is omitted in FIG. It is. Further, the following description will be made on the assumption that the air conditioner 100 is performing a normal cooling operation.

  The refrigerant circuit 20 is configured by connecting a compressor 201, a four-way switching valve 202, an outdoor heat exchanger 203, a main expansion valve (main throttle unit) 204, and an indoor heat exchanger 205. is there. In the present embodiment, the compressor 201, the four-way switching valve 202, and the outdoor heat exchanger 203 are provided inside the outdoor unit 10, and the main expansion valve 204 and the evaporator 205 are provided inside the indoor unit 11. It is the structure which was made.

  The outdoor heat exchanger 203 is divided into a first outdoor heat exchanger 203a and a second outdoor heat exchanger 203b.

  The four-way switching valve 202 includes a first four-way valve 202a and a second four-way valve 202b respectively corresponding to the first outdoor heat exchanger 203a and the second outdoor heat exchanger 203b.

  The discharge side of the compressor 201 is branched, and one of the branched branches is connected to the D port of the first four-way valve 202a, and the C port of the first four-way valve 202a is on the cooling inlet side of the first outdoor heat exchanger 203a. It is connected to the. The other branched side is connected to the D port of the second four-way valve 202b, and the C port of the second four-way valve 202b is connected to the cooling side inlet side of the second outdoor heat exchanger 203b.

  Further, the cooling outlet side of the first outdoor heat exchanger 203a and the cooling outlet side of the second outdoor heat exchanger 203b are joined at the first connection point X. Here, between the cooling-time inlet side of the second outdoor heat exchanger 203b and the first connection point X, a first throttle portion (first expansion valve) 206 is provided. The valve opening degree of the first expansion valve 206 is controlled by the air conditioner control unit 30.

  The A port of the first four-way valve 202a is connected to the cooling side outlet side of the indoor heat exchanger 205. The B port of the first four-way valve 202a is connected to the A port of the second four-way valve 202b. The B port of the second four-way valve 202b is connected to the suction side of the compressor 201.

  In the refrigerant circuit 20, a branch from a pipe (hereinafter also referred to as BA connection pipe 21) connecting the B port of the first four-way valve 202 a and the A port of the second four-way valve 202 b, and the suction side of the compressor 201. The branch flow path 22 that merges at the second connection point Y is provided. The branch flow path 22 is provided with a second throttle portion (second expansion valve) 207. The branch flow path 22 branches from the pipe connecting the A port of the first four-way valve 202a and the indoor heat exchanger 205 in addition to the structure branching from the BA connection pipe 21, and joins at the second connection point Y. It may be configured to do so.

  In the refrigerant circuit 20 described above, the second outdoor heat exchanger 203b serving as an auxiliary heat exchanger is provided on the connection flow path connecting the first connection point X and the second connection point Y, and the second outdoor heat exchanger 203b is provided in the connection flow path. The first expansion valve 206 is provided on the first connection point X side of the heat exchanger 203b, and the second expansion valve 207 is provided between the second connection point Y and the indoor heat exchanger 205.

  In addition, a check valve 209 is provided on the downstream side of the branch point of the branch flow path 22 in the BA connection pipe 21. Furthermore, an electromagnetic on-off valve 210 is provided in the bypass pipe 23 that connects between the branch point and the check valve 209 and the pipe connecting the B port of the second four-way valve 202b and the suction side of the compressor 201. Yes. The opening / closing of the electromagnetic opening / closing valve 210 is controlled by the air conditioner control unit 30.

  Next, operation | movement of the air conditioner 100 of this embodiment is demonstrated.

(1) During normal cooling operation During normal cooling, as shown in FIG. 1, the first four-way valve 202a and the second four-way valve 202b communicate the A port and the B port, respectively, and connect the C port and the D port. Communicate. For this reason, the refrigerant discharged from the discharge side of the compressor 201 passes through the first four-way valve 202a and the second four-way valve 202b, passes through the first outdoor heat exchanger 203a and the second outdoor heat exchanger 203b, Merges at one connection point X and flows to the indoor unit 11 side.

  The refrigerant returned from the indoor unit 11 flows into the A port of the first four-way valve 202a, flows out of the B port, flows into the A port of the second four-way valve 202b, and flows out of the B port. Return to the suction side of the compressor 201.

  At this time, since the opening degree of the second expansion valve 207 does not affect the refrigerant, there is no problem whether it is opened or closed. Further, there is no problem with either opening / closing of the electromagnetic opening / closing valve 210 provided in the bypass pipe 23. The first expansion valve 206 is open.

(2) During normal heating operation During normal heating, as shown in FIG. 2, the first four-way valve 202a and the second four-way valve 202b communicate the B port and the C port, respectively, and connect the A port and the D port. Communicate. For this reason, the refrigerant discharged from the discharge side of the compressor 201 is divided into a first four-way valve 202a and a second four-way valve 202b, the first four-way valve 202a side flows into the D port, flows out from the A port, and gas It flows through the pipe to the indoor unit 11. On the other hand, the second four-way valve 202b side flows into the D port, but stops at the check valve 209 at the A port outlet.

  Further, the refrigerant returned from the indoor unit 11 is depressurized by the expansion valve 206 after passing through the main expansion valve 204, and then is divided into the first outdoor heat exchanger 203a and the second outdoor heat exchanger 203b. The air flows into the C port of the first four-way valve 202a and the second four-way valve 202b, flows out from the B port, and returns to the suction side of the compressor 201. At this time, the second expansion valve 207 is opened. The opening / closing of the electromagnetic on-off valve 210 provided in the bypass pipe 23 that bypasses the A port and B port of the second four-way valve 202b is also opened to reduce pressure loss. If there is no problem with pressure loss due to a low circulation amount or the like, there is no problem even if the solenoid valve 210 is closed or deleted.

(3) During cooling operation at low outside air temperature During cooling operation at low outside air temperature, as shown in FIG. 3, the first four-way valve 202a communicates the A port and the B port and communicates the C port and the D port. To do. The second four-way valve 202b communicates the A port and the D port and communicates the B port and the C port. The refrigerant discharged from the discharge side of the compressor 201 flows into the D port of the first four-way valve 202a, flows out from the C port, and flows to the first outdoor heat exchanger 203a. At this time, the first outdoor heat exchanger 203a is a condenser. The refrigerant after passing through the first outdoor heat exchanger 203a is divided into the second outdoor heat exchanger 203b side and the indoor unit 11 side at the first connection point X.

  The refrigerant that has flowed to the second outdoor heat exchanger 203b side is restricted to a pressure that can evaporate even at a low outdoor temperature by the first expansion valve 206, and flows to the second outdoor heat exchanger 203b. At this time, the second outdoor heat exchanger 203b becomes an evaporator (auxiliary heat exchanger).

Here, the valve opening degree of the first expansion valve 206 is controlled by the air conditioner control unit 30 as follows.
That is, the air conditioner control unit 30 acquires the outside air temperature T [° C.] from the outside air temperature sensor 211 provided in the outdoor unit 10, and the second outdoor heat exchanger 203 b with respect to the outside air temperature T [° C.]. Is set to the evaporation pressure at (T-5) [° C.]. The air conditioner control unit 30 acquires the suction pressure (low pressure) from the suction side pressure sensor 212 provided on the suction side of the compressor 201, and the suction pressure evaporates at (T-5) [° C]. The valve opening degree of the first expansion valve 206 is feedback controlled so that the pressure is reached.

  The refrigerant returned from the indoor unit 11 flows into the A port of the first four-way valve 202a, flows out from the B port, and flows to the second expansion valve 207 side provided in the branch flow path 22. The refrigerant flowing through the second expansion valve 207 is decompressed by the second expansion valve 207 in order to merge with the refrigerant that has passed through the second outdoor heat exchanger 203b at the second connection point Y.

Here, the valve opening degree of the second expansion valve 207 is controlled by the air conditioner control unit 30 as follows.
That is, the air conditioner control unit 30 acquires the outside air temperature T [° C.] from the outside air temperature sensor 211 provided in the outdoor unit 10, and the second outdoor heat exchanger 203 b with respect to the outside air temperature T [° C.]. Is set to the evaporation pressure at (T-5) [° C.]. The air conditioner control unit 30 acquires the suction pressure (low pressure) from the suction pressure sensor 212 provided on the suction side of the compressor 201, and the suction pressure is the evaporation pressure at (T-5) [° C.]. The valve opening degree of the second expansion valve 207 is feedback-controlled so that

  The main expansion valve 204 of the indoor unit 11 differs from the first expansion valve 206 and the second expansion valve 207, for example, by changing the inlet temperature of the indoor heat exchanger 205 and the outlet temperature of the indoor heat exchanger 205. The degree of superheat is calculated by detection, and the valve opening degree is controlled using the degree of superheat.

  The refrigerant decompressed by the second expansion valve 207 merges with the refrigerant that has passed through the second outdoor heat exchanger 203b, and returns to the suction side of the compressor 201. At this time, the electromagnetic on-off valve 210 provided in the bypass pipe 23 that bypasses the A port and the B port of the second four-way valve 202b is closed.

  According to the air conditioner 100 of the present embodiment configured as described above, the evaporation pressure of the second outdoor heat exchanger (auxiliary heat exchanger) 203b and the evaporation pressure of the indoor heat exchanger 205 are different from each other. The second outdoor heat exchanger 203b can function as an evaporator even at an outdoor temperature lower than the room temperature, such as a temperature lower than the freezing temperature, and freezing such as freezing on the surface of the indoor heat exchanger 205 is possible. Can be prevented. Therefore, even in a cooling operation at a low outside air temperature (for example, under a condition where the outside air temperature is lower than the room temperature), the cooling operation is smoothly performed by balancing the heat exchange amount of the condenser and the heat exchange amount of the evaporator. be able to. Specifically, for example, cooling under a low outside air temperature condition of −5 ° C. or lower is possible. In addition, it is possible to prevent the indoor temperature from being fluctuated due to the thermo-off that frequently occurs due to the excessive cooling capacity that occurs at the low outside air temperature.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 4, the air conditioner 100 according to the second embodiment includes an outdoor unit 10 installed outside a building, an indoor unit 11 installed inside the building, and the outdoor unit 10 and the indoor unit 11 as refrigerant. A refrigerant circuit 20 connected by a pipe 12, an air conditioner outdoor unit control unit 30 and an air conditioner indoor control unit 31 which are control devices for controlling the outdoor unit 10, the indoor unit 11 and the like to perform an air conditioning operation; It has. The air conditioner outdoor unit control unit 30 and the air conditioner room control unit 31 control each unit of the air conditioner 100. The air conditioner outdoor unit control unit 30 and the air conditioner room control unit 31 are connected to each part of the indoor unit 11 and the outdoor unit 10, but the connection description is omitted in FIG. It is.

  The refrigerant circuit 20 is configured by connecting a compressor 201, a four-way switching valve 202, an outdoor heat exchanger 203, a main expansion valve (main throttle unit) 204, and an indoor heat exchanger 205. is there. In the present embodiment, the compressor 201, the four-way switching valve 202, and the outdoor heat exchanger 203 are provided inside the outdoor unit 10, and the main expansion valve 204 and the evaporator 205 are provided inside the indoor unit 11. It is the structure which was made. Note that the outdoor heat exchanger 203 of the present embodiment is not divided.

  The refrigerant pipe 12 has a gas side refrigerant pipe 121 and a liquid side refrigerant pipe 122. The gas side refrigerant pipe 121 connects the evaporator 205 of the indoor unit 11 and the four-way switching valve 202 of the outdoor unit 10. The liquid side refrigerant pipe 122 connects the condenser 203 (main expansion valve 204) of the outdoor unit 10 and the evaporator 205 of the indoor unit.

  The auxiliary unit 13 includes a gas side internal pipe 131 that is detachably connected to the gas side refrigerant pipe 121, a liquid side internal pipe 132 that is detachably connected to the liquid side refrigerant pipe 122, and a liquid side internal pipe 132. A connection flow path (connection pipe) 133 connected to the first connection point X and the second connection point Y of the gas side internal pipe 131 and an auxiliary heat exchanger 134 provided in the connection pipe 133 are provided.

  A first throttle part (first expansion valve) 135 is provided on the connection pipe 133 on the first connection point X side of the auxiliary heat exchanger 134. The valve opening degree of the first expansion valve 135 is controlled by the air conditioner control unit 30.

  A second throttle portion (second expansion valve) 136 is provided upstream of the second connection point Y in the gas side internal pipe 131. The valve opening degree of the second expansion valve 136 is controlled by the air conditioner control unit 30.

  Further, a bypass pipe 137 that bypasses the second connection point Y and the second expansion valve 136 is connected to the gas side internal pipe 131. The bypass pipe 137 is provided with an electromagnetic opening / closing valve 138. The opening / closing of the electromagnetic opening / closing valve 138 is controlled by the air conditioner control unit 30.

  Further, in the gas-side internal pipe 131, a check that causes the refrigerant flowing from the second connection point Y toward the connection point Z to flow between the connection point Z on the outdoor unit side and the second connection point Y with the bypass pipe 137. A valve 139 is provided.

Next, operation | movement of the air conditioner 100 comprised in this way is demonstrated easily.
During normal cooling operation and heating operation, the electromagnetic on-off valve 138 is opened, and the first expansion valve 135 and the second expansion valve 136 are closed. Thereby, the refrigerant does not flow into the auxiliary heat exchanger 134 provided in the auxiliary unit 13.

  During the cooling operation at the low outside air temperature, the electromagnetic on-off valve 138 is closed and the first expansion valve 135 and the second expansion valve 136 are opened. Thereby, a refrigerant flows into auxiliary heat exchanger 134, and auxiliary heat exchanger 134 functions as an evaporator.

  At this time, the valve opening degree of the first expansion valve 136 and the valve opening degree of the second expansion valve 137 are controlled in the same manner as in the first embodiment.

  According to the air conditioner 100 of the present embodiment configured as described above, the evaporating pressure of the auxiliary heat exchanger 134 and the evaporating pressure of the indoor heat exchanger 205 are different from each other, so that the outside air temperature is lower than the freezing point. Even at an outdoor temperature lower than the indoor temperature, the auxiliary heat exchanger 134 can function as an evaporator, and freezing such as freezing on the surface of the indoor heat exchanger 205 can be prevented. Therefore, even in a cooling operation at a low outside air temperature (for example, under a condition where the outside air temperature is lower than the room temperature), the cooling operation is smoothly performed by balancing the heat exchange amount of the condenser and the heat exchange amount of the evaporator. be able to. Specifically, for example, cooling under a low outside air temperature condition of −5 ° C. or lower is possible. In addition, it is possible to prevent the indoor temperature from being fluctuated due to the thermo-off that frequently occurs due to the excessive cooling capacity that occurs at the low outside air temperature. Furthermore, the said function can be provided to the existing air conditioner 100 only by attaching the auxiliary | assistant unit 13 to the existing air conditioner 100 externally.

  In addition, you may comprise the auxiliary | assistant unit 13 of 2nd Embodiment from the 1st auxiliary | assistant unit 13a and the 2nd auxiliary | assistant unit 13b, as shown in FIG. The first auxiliary unit 13a is provided with a liquid side internal pipe 132, an auxiliary heat exchanger 134, and a first expansion valve 136, and the second auxiliary unit 13b has a gas side internal pipe 131 and a second expansion valve 137. In addition, a bypass pipe 137 and the like are provided. The first auxiliary unit 13a may be configured using an existing indoor unit. The operation of the auxiliary unit configured as described above is the same as that of the second embodiment.

  The present invention is not limited to the above embodiments.

As shown in FIG. 6, in the air conditioner of the first embodiment, a plurality of indoor units and outdoor units may be connected. In this case, the driving situation changes as follows according to the capacity balance between the indoor unit and the outdoor unit.
(1) When the capacity of the indoor unit is sufficient, all the plurality of outdoor units are operated in a normal cooling operation.
(2) When the capacity of the indoor unit decreases, the number of outdoor units operated is gradually decreased to operate.
(3) When the capacity of the indoor unit is further reduced and balance cannot be achieved even when one outdoor unit is operated, the circuit is switched to the circuit of the first embodiment, and a part of the divided outdoor heat exchanger is used as an evaporator. To compensate for the lack of evaporation capacity.

  Moreover, in the said embodiment, although the valve opening degree of the 1st, 2nd expansion valve was feedback-controlled so that the suction pressure of a compressor might become the evaporation pressure of (T-5) [degreeC], others The control may be performed as follows.

  That is, an intake temperature sensor for measuring the refrigerant intake temperature into the compressor 201 is provided, and the air conditioner control unit 30 calculates the evaporation pressure of the auxiliary heat exchanger ((T−) from the outside air temperature obtained by the outside air temperature sensor. 5) The evaporation pressure at [° C.] is determined, the suction temperature obtained by the suction temperature sensor is acquired, and the valve opening degrees of the first and second expansion valves 206 and 207 are feedback-controlled.

  Further, the air conditioner control unit 30 feedback-controls the valve openings of the first and second expansion valves 206 and 207 so that the degree of superheat of the suction pipe of the compressor 201 is constant.

  Both the first throttle part and the second throttle part in the embodiment may be made of a capillary, or one of the first throttle part and the second throttle part may be a capillary.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

DESCRIPTION OF SYMBOLS 100 ... Air conditioner 10 ... Outdoor unit 20 ... Refrigerant circuit 30 ... Air conditioner control part (control apparatus)
DESCRIPTION OF SYMBOLS 11 ... Indoor unit 201 ... Compressor 203 ... Outdoor heat exchanger 204 ... Main throttle part 205 ... Indoor heat exchanger 203b ... 2nd outdoor heat exchanger (auxiliary heat exchanger )
206 ... 1st throttle part 207 ... 2nd throttle part X ... 1st connection point Y ... 2nd connection point 211 ... Outside temperature sensor 212 Intake pressure sensor 12 ... Connection piping 13 ... Auxiliary units

Claims (10)

An air conditioner having a refrigerant circuit in which a compressor, an outdoor heat exchanger, a main throttle unit, and an indoor heat exchanger are connected in this order,
In the refrigerant circuit, provided in a connection flow path that connects a first connection point between the outdoor heat exchanger and the main throttle part and a second connection point between the indoor heat exchanger and the compressor. An auxiliary heat exchanger,
A first throttle portion provided on the upstream side of the auxiliary heat exchanger in the connection flow path;
A second throttle part provided between the second connection point and the indoor heat exchanger in the refrigerant circuit;
An air conditioner configured such that the evaporating pressure of the auxiliary heat exchanger is different from the evaporating pressure of the indoor heat exchanger by the first throttle unit and the second throttle unit. The refrigerant circuit has a four-way valve for switching a refrigerant flow direction during cooling operation and a refrigerant flow during heating operation,
The second connection point is provided between the four-way valve and the compressor in the refrigerant circuit,
The second restrictor includes a branch channel that branches from a pipe from which the refrigerant returns from the four-way valve to the compressor side in the refrigerant circuit and merges with the second connection point, or the four-way valve in the refrigerant circuit and 2. The air conditioner according to claim 1, wherein the air conditioner is provided in a branch passage that branches off from a pipe connecting the indoor heat exchanger and joins the second connection point. The first throttle part and the second throttle part are expansion valves;
The control device for controlling the valve opening degree of the expansion valve controls the valve opening degree of the first and second throttle parts according to the outside air temperature, and the evaporation pressure of the auxiliary heat exchanger is exchanged with the indoor heat. The air conditioner according to claim 1 or 2, wherein the air conditioner is different from the evaporation pressure of the vessel. An outside temperature sensor for measuring the outside temperature;
A suction pressure sensor for measuring the suction pressure of the refrigerant into the compressor,
The control device determines the evaporation pressure of the auxiliary heat exchanger from the outside air temperature obtained by the outside air temperature sensor, acquires the suction pressure obtained by the suction pressure sensor, and the first and second throttle parts The air conditioner according to claim 3, wherein the valve opening degree is feedback-controlled. An outside temperature sensor for measuring the outside temperature;
An intake temperature sensor for measuring the intake temperature of the refrigerant into the compressor,
The control device determines the evaporation pressure of the auxiliary heat exchanger from the outside air temperature obtained by the outside air temperature sensor, acquires the suction temperature obtained by the suction temperature sensor, and the first and second throttle parts The air conditioner according to claim 3, wherein the valve opening degree is feedback-controlled.   The air conditioner according to claim 3, wherein the control device feedback-controls the valve opening degrees of the first and second throttle portions so that the degree of superheat of the suction pipe of the compressor is constant. The outdoor heat exchanger is divided into a plurality of parts,
The air conditioner according to any one of claims 1 to 6, wherein the divided outdoor heat exchanger is configured as the auxiliary heat exchanger.   The air conditioner according to any one of claims 1 to 6, wherein the auxiliary heat exchanger is configured by an indoor heat exchanger of another air conditioner.   The air conditioner according to claim 1, wherein the second throttle portion is constituted by a capillary. An outdoor unit having the compressor and the outdoor heat exchanger, an indoor unit having the main throttle unit and the indoor heat exchanger, and a connection pipe connecting the outdoor unit and the indoor unit,
The air conditioner according to any one of claims 1 to 9, wherein the auxiliary heat exchanger, the first throttle unit, and the second throttle unit are provided in an auxiliary unit that is externally attached to the connection pipe. .