JP2005049080A - Control method of air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To start, at the time of cooling dehumidifying operation, the cooling dehumidifying operation after performing cooling operation for a predetermined time only when the compressed state of a refrigerant in an outdoor heat exchanger is poor (the compression is not better). <P>SOLUTION: In an air conditioner in which an expansion valve having a pressure reducing function varied depending on the direction of carrying the refrigerant is interposed between two divided indoor heat exchangers to perform cooling dehumidifying operation or heating dehumidifying operation by use of the expansion valve, the compressed state of the refrigerant in the outdoor heat exchanger is determined, at the time of the cooling dehumidifying operation, in reference to the previous operation mode, the stopping time of a compressor, and the temperature of the outdoor heat exchanger (steps ST2-ST4). On the basis of this, it is determined whether the cooling dehumidifying operation is started without cooling operation or after performing the cooling operation for a determined time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control method for an air conditioner having a dehumidifying operation mode in addition to a cooling operation and a heating operation. More specifically, the present invention relates to an indoor heat exchanger that is divided into a condenser in the dehumidifying operation mode, and the other The present invention relates to a control method for an air conditioner that performs cooling and dehumidifying operation by heating as a vaporizer.

  In addition to the cooling and heating operations, the air conditioner is equipped with a cooling and dehumidifying operation (cooling cycle reheat dehumidifying operation) that dehumidifies the room without impairing comfort, and a heating and dehumidifying operation (heating cycle reheat and dehumidifying operation). Some have different modes of operation.

  As shown in FIG. 3, the refrigeration cycle of this type of air conditioner includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a first expansion valve 4, a first and a second two indoor heat exchangers. The connection refrigerant pipe 7 that includes the first indoor heat exchanger 5 and the second indoor heat exchanger 6 includes a bidirectional solenoid valve 8 and a second expansion valve (pressure reducing valve) 9 in parallel. Provided.

  During the cooling operation, the two-way solenoid valve 8 is opened, and the refrigerant discharged from the compressor 1 is used as the four-way valve 2 → the outdoor heat exchanger 3 → the first expansion valve 4 → the first indoor heat exchanger 5 → both. The electromagnetic valve 8 → second indoor heat exchanger 6 → returns to the compressor 1 via the refrigerant flow path of the four-way valve 2, and the outdoor heat exchanger 3 acts as a condenser to perform the first and second indoor heat exchanges. Both units 5 and 6 act as evaporators. During the heating operation, the refrigerant flow is reversed, and the first and second indoor heat exchangers 5 and 6 are both acted as condensers, and the outdoor heat exchanger 3 is acted as an evaporator.

  During the cooling and dehumidifying operation, the first expansion valve 4 is opened and the bidirectional electromagnetic valve 8 is closed so that the refrigerant passes through the second expansion valve 9 without passing through the bidirectional electromagnetic valve 8. As the second expansion valve 9, an expansion valve that exhibits different pressure reducing functions depending on the flow direction of the refrigerant is used (see Patent Document 1 proposed by the applicant).

  That is, as shown in FIGS. 4 and 5, the second expansion valve 9 has a valve body including a first valve body 9a having a large diameter and a second valve body 9b having a small diameter formed on the same axis. The rod-shaped valve body 9a is movably accommodated therein. Although not shown, silencers made of, for example, a net are provided at both ends of the valve body.

  The valve body 9a moves according to the flow direction of the refrigerant to form decompression sections having different lengths. For example, during cooling operation, the refrigerant flows in the direction of the broken line arrow in FIG. On the other hand, since the refrigerant flows in the direction of the broken line arrow in FIG. 5 during the heating operation, the valve body 9a is moved to the right side. As a result, different decompression states can be obtained during the cooling operation and the heating operation.

  Due to the operation of the second expansion valve 9, the second indoor heat exchanger 6 acts as an evaporator in the cooling and dehumidifying operation, but the first indoor heat exchanger 5 acts as the same condenser as the outdoor heat exchanger 3. Therefore, the room temperature can be prevented from dropping too much. Further, since the heating and dehumidifying operation is opposite to the cooling and dehumidifying operation, an excessive increase in the room temperature can be suppressed.

  However, when the cooling and dehumidifying operation is performed when the outside air temperature is extremely low, the temperature of the outdoor heat exchanger 3 is low, so that the condensation of the refrigerant in the outdoor heat exchanger 3 is not smoothly performed. Since the amount of condensation increases and the refrigerant stagnates and the gas refrigerant escapes, the refrigerant pressure difference between the first indoor heat exchanger 5 side and the second indoor heat exchanger 6 side increases.

  Thereby, a refrigerant | coolant may flow into the 2nd expansion valve 9 suddenly, and a vibration and noise may generate | occur | produce. Therefore, in Patent Document 1, when the temperature of the outdoor heat exchanger is low, the cooling operation is performed for a certain period of time before the cooling and dehumidifying operation is performed, and the refrigerant is passed through the bidirectional solenoid valve 8 to reduce the pressure difference. ing.

However, in the above Patent Document 1, when performing the cooling and dehumidifying operation, if the outdoor air temperature is low and the temperature of the outdoor heat exchanger is equal to or lower than a predetermined value, the cooling operation is uniformly performed for a certain period of time. The followability may be deteriorated and the dehumidifying performance may be lowered. That is, there is a problem that even if the room temperature is excessively lowered by the cooling operation and the operation is switched to the cooling and dehumidifying operation, the low room temperature does not rise easily, and the dehumidifying efficiency does not rise due to the low room temperature.
Japanese Patent Application No. 2003-042356

  Accordingly, an object of the present invention is to determine whether or not to perform a cooling operation according to the situation at the time when performing a cooling and dehumidifying operation, and to suppress a decrease in room temperature control follow-up performance, dehumidifying performance, and the like.

  In order to solve the above problems, the present invention includes a refrigeration cycle including a compressor, a four-way valve, an outdoor heat exchanger, a first expansion valve, and an indoor heat exchanger, and the indoor heat exchanger is a first indoor heat exchanger. And a second indoor heat exchanger, between the first indoor heat exchanger and the second indoor heat exchanger, a bidirectional solenoid valve and a different pressure reducing function depending on the flow direction of the refrigerant And the second expansion valve connected in parallel. During the cooling and dehumidifying operation, the two-way solenoid valve is closed, the first expansion valve is opened, and the outdoor heat exchanger and the first indoor heat exchanger are connected. While acting as a condenser, the second indoor heat exchanger acts as an evaporator, and during the heating and dehumidifying operation, the bidirectional solenoid valve is closed, the first expansion valve is opened, and the second indoor heat exchanger is opened. While acting as a condenser, the first indoor heat exchanger and the outdoor In the control method of the air conditioner that causes the exchanger to function as an evaporator, when performing the cooling and dehumidifying operation, the cooling operation is performed for a predetermined time prior to the cooling and dehumidifying operation according to the state of refrigerant condensation in the outdoor heat exchanger. It is characterized in that it is determined whether to start the cooling and dehumidifying operation immediately without performing the cooling operation.

  In the present invention, the determination includes the operation state before the cooling and dehumidifying operation, the stop time of the compressor before the cooling and dehumidifying operation, or the outdoor heat exchanger when performing the cooling and dehumidifying operation. At least one of the temperatures is taken into account.

  That is, when the operation state before performing the cooling and dehumidifying operation is the heating operation or the heating and dehumidifying operation, the cooling operation is performed for a predetermined time before the cooling and dehumidifying operation is performed.

  When the operation state before performing the cooling and dehumidifying operation is an operation state other than the heating operation or the heating and dehumidifying operation, the stop time of the compressor is a predetermined time or more, and the temperature Tn of the outdoor heat exchanger is When the temperature is lower than the predetermined value, the cooling operation is performed for a predetermined time before the cooling and dehumidifying operation is performed.

  In this way, in the present invention, the cooling operation is performed before the cooling and dehumidifying operation in the case of a specific condition. During the cooling operation, a temperature difference between the room temperature Tr and the temperature Te of the indoor heat exchanger is predetermined. When it becomes larger than the value, the cooling operation is stopped and the cooling and dehumidifying operation is started.

  In addition, even when the temperature difference between the room temperature Tr and the temperature Te of the indoor heat exchanger is smaller than a predetermined value, the cooling operation is stopped when the operation time of the cooling operation has elapsed for a predetermined time. Start dehumidifying operation.

  Further, when the operation state before performing the cooling and dehumidifying operation is a heating operation or an operating state other than the heating and dehumidifying operation, the cooling operation is not performed when the predetermined period of time has not elapsed for the compressor. The cooling and dehumidifying operation is started.

  According to the present invention, the second expansion valve serving as a decompression unit having a decompression function that differs in the refrigerant flow direction is interposed between the first and second indoor heat exchangers, and cooling dehumidification is performed using the expansion valve. In an air conditioner that can be operated or heated and dehumidified, when performing the cooling and dehumidifying operation, the current condition is determined based on the previous operating state, compressor stop time, outdoor heat exchanger temperature, etc. It is determined whether or not the condensation in the exchanger is performed smoothly, and after the cooling operation is performed for a predetermined time based on the determination result, the cooling and dehumidifying operation is started, or the cooling and dehumidifying operation is started immediately without performing the cooling operation. Therefore, the pressure difference between the refrigerant output side of the first indoor heat exchanger and the refrigerant input side of the second indoor heat exchanger does not increase, and vibration and noise generation of the second expansion valve can be suppressed. Not Room temperature control followability in cooling and dehumidifying operation because it requires without the necessity of cooling operation, the effect is exhibited that decreases such dehumidification performance is suppressed.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited to this. In addition, the structure of a refrigerating cycle and the structure of the 2nd expansion valve provided between indoor heat exchangers may be the same as FIG. 3 and FIG. 4 which were demonstrated previously.

  In the present invention, at the start of the cooling and dehumidifying operation, not only the temperature of the outdoor heat exchanger but also the previous operation state, whether to perform the cooling operation taking into account the operation stop time of the compressor, etc. The cooling operation time is determined based on the difference from the temperature of the indoor heat exchanger, and the cooling dehumidification operation (cooling cycle reheat dehumidification operation) is performed after the cooling operation.

  Therefore, the control system shown in FIG. 2 is provided. This control system includes a control circuit 20 on the indoor unit side and a control circuit 21 on the outdoor unit side, and performs control necessary for room temperature control according to a remote control signal from the remote controller 22. In addition to the first and second indoor heat exchangers 5 and 6, the bidirectional solenoid valve 8, and the second expansion valve (pressure reducing valve) 9, the indoor unit side includes a room temperature sensor 23 and an indoor heat exchanger. A temperature sensor 24, an indoor fan 25, and the like are provided.

  Although not shown in detail, in this example, the first and second indoor heat exchangers 5 and 6 are arranged in a lambda shape from the rear side to the front side of the indoor unit, and the first indoor heat exchanger 5 is It arrange | positions at the back side and the 2nd indoor heat exchanger 6 is arrange | positioned at the front side. On the outdoor unit side, in addition to the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, and the first expansion valve (capillary tube) 4, an outdoor heat exchanger temperature sensor 26 and an outdoor fan 27 are provided. .

  The control circuit 20 on the indoor unit side detects a room temperature Tr based on a signal from a determination unit 20a that decodes a remote control signal to determine an operation mode, a state determination unit 20b that determines a current operation state, and a room temperature sensor 23. Unit 20c, a temperature detection unit 20d of the indoor heat exchanger that detects the temperature Te of the indoor heat exchanger by a signal from the temperature sensor 24 of the indoor heat exchanger, a storage unit 20e that stores the detected temperature, and the routine shown in FIG. Each function of the timer unit 20f used when executing is executed.

  The control circuit 21 on the outdoor unit side receives a signal from the indoor unit side to determine the operation mode, the determination unit 21a, the compressor control unit 21b that drives the compressor 1 to the command rotational speed, and the four-way valve 2 to the operation mode. The four-way valve control unit 21c that switches according to the function of the temperature detection unit 21d of the outdoor heat exchanger that detects the temperature Tn of the outdoor heat exchanger based on a signal from the temperature sensor 26 of the outdoor heat exchanger is provided.

  Next, the operation of this air conditioner will be described with reference to the flowchart of FIG. First, if the instruction from the remote controller 22 is a cooling operation or a heating operation, the first expansion valve 4 is controlled to be throttled and the bidirectional electromagnetic valve 8 is opened. On the other hand, when the dehumidifying operation is set, the first expansion valve 4 is opened and the bidirectional solenoid valve 8 is closed.

  In step ST1, when the dehumidifying operation is based on the cooling cycle, that is, in the cooling cycle reheat dehumidifying operation, the first expansion valve 4 is opened, the bidirectional solenoid valve 8 is closed, and the second expansion valve 9 Depressurize the refrigerant.

  When starting this cooling and dehumidifying operation, it is determined in step ST2 whether or not the previous operating state is a heating operation or a heating and dehumidifying operation. If the result is YES and the heating operation or the heating / dehumidifying operation is performed, the temperature of the outdoor heat exchanger 3 is often extremely low, so jump to step ST5 and start the cooling / dehumidifying operation. Cooling operation is performed and the temperature of the outdoor heat exchanger 3 is raised.

  If the determination in step ST2 is NO and the previous time is not heating operation or heating dehumidification operation, it is determined whether or not a predetermined time (120 minutes in this example) has elapsed since the compressor 1 was stopped in step ST3. To do. If the result is NO and within 120 minutes after the previous operation is stopped, the temperature of the outdoor heat exchanger 3 remains somewhat high, is not close to the outside air temperature, and the cooling operation is performed prior to the start of the cooling and dehumidifying operation. Since it is not necessary to perform this operation, the process jumps to step ST10 to execute the cooling and dehumidifying operation.

  If the result in step ST3 is YES and the stop time of the compressor 1 has continued for 120 minutes or longer, is the temperature Tn of the outdoor heat exchanger 3 lower than, for example, 15 ° C. in step ST4 in the next stage? Judge whether or not. If the result is NO and the temperature Tn of the outdoor heat exchanger is 15 ° C. or higher, it is not necessary to perform the cooling operation prior to the start of the cooling and dehumidifying operation, and therefore, jump to step ST10 and execute the cooling and dehumidifying operation.

  If the result in step ST4 is YES, that is, if the outdoor heat exchanger temperature Tn is lower than 15 ° C., the cooling operation is performed in step ST5 prior to the start of the cooling and dehumidifying operation. Thus, the smoothness of condensation in the outdoor heat exchanger 3 (condensation is based on the previous operating state, the compressor stop time or the temperature of the outdoor heat exchanger, or a combination thereof) State), and when it is determined that the condensation is not performed smoothly, the cooling operation is performed for a predetermined time prior to the cooling and dehumidifying operation.

  In the cooling operation in step ST5, the bidirectional solenoid valve 8 is opened and the first expansion valve 4 is throttled with the initial pulse. Subsequently, in step ST6, the 5-minute timer of the timer unit 20f is started, and in step ST7, masking is performed for 30 seconds for performing the cooling operation for at least 30 seconds.

  After the 30-second mask, the temperature difference between the room temperature Tr and the temperature Te of the indoor heat exchanger is calculated until the 5-minute timer expires, and it is determined whether or not this temperature difference is higher than 5 ° C. (step ST8, ST9). The temperature Te of the indoor heat exchanger may be the temperature of the second indoor heat exchanger 6, for example.

  With this cooling operation, the temperature Te of the indoor heat exchanger decreases, and accordingly, the room temperature Tr also decreases. When the temperature difference (Tr-Te) becomes 5 ° C. or higher, step ST10 is executed to perform the cooling and dehumidifying operation. To start. That is, it can be determined that the temperature of the outdoor heat exchanger 3 has risen to some extent. If the room temperature Tr decreases too close to the temperature Te of the indoor heat exchanger, the follow-up performance of the room temperature control in the subsequent cooling and dehumidifying operation This is because the dehumidifying ability is lowered.

  Even if the condition of Tr-Te> 5 ° C. is not satisfied, it can be determined that the temperature of the outdoor heat exchanger 3 has risen to some extent if the cooling operation is continued for 5 minutes. Jump to and start cooling and dehumidifying operation. If it is determined in step ST1 that the operation is not the cooling and dehumidifying operation, that is, if the heating and dehumidifying operation is performed, the process proceeds to step 11 and the heating and dehumidifying operation is performed.

  Thus, prior to performing the cooling and dehumidifying operation, the temperature of the outdoor heat exchanger 3 is increased by performing the cooling operation only when the refrigerant is not condensed in the outdoor heat exchanger 3 smoothly. Since the desired condensing capacity is exhibited, the refrigerant pressure difference between the first indoor heat exchanger 5 side and the second indoor heat exchanger 6 side is reduced, and vibration and noise of the second expansion valve 9 are suppressed. Further, it is possible to suppress a decrease in room temperature control followability, dehumidification performance, and the like.

The flowchart explaining operation | movement of the air conditioner controlled by this invention. The schematic block diagram which shows the control apparatus of the air conditioner for implementing the control method of this invention. The schematic diagram which shows the refrigerating cycle of the air conditioner which enabled air conditioning dehumidification and heating dehumidification. The schematic sectional drawing which shows the time of the 1st effect | action of the 2nd expansion valve (pressure reduction valve) contained in the said refrigerating cycle. The schematic sectional drawing which shows the time of the 2nd effect | action of the 2nd expansion valve (pressure reduction valve) contained in the said refrigerating cycle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 1st expansion valve 5 1st indoor heat exchanger 6 2nd indoor heat exchanger 7 Connection refrigerant pipe 8 Bidirectional solenoid valve (open / close solenoid valve)
9 Second expansion valve (pressure reducing valve)
9a 1st valve body part 9b 2nd valve body part 9c Valve body 20,21 Control circuit 22 Remote control 23 Room temperature sensor 24 Temperature sensor of indoor heat exchanger 25 Indoor fan 26 Temperature sensor of outdoor heat exchanger 27 Outdoor fan

Claims (7)

A refrigeration cycle including a compressor, a four-way valve, an outdoor heat exchanger, a first expansion valve, and an indoor heat exchanger is provided, and the indoor heat exchanger includes a first indoor heat exchanger and a second indoor heat exchanger. Between the first indoor heat exchanger and the second indoor heat exchanger, a bidirectional solenoid valve and a second expansion valve that exhibits a different pressure reducing function according to the flow direction of the refrigerant are connected in parallel. And
During the cooling and dehumidifying operation, the bidirectional solenoid valve is closed, the first expansion valve is opened, and the outdoor heat exchanger and the first indoor heat exchanger are operated as a condenser, while the second indoor heat exchanger is operated. Is operated as an evaporator, and during the heating and dehumidifying operation, the bidirectional solenoid valve is closed, the first expansion valve is opened, and the second indoor heat exchanger is operated as a condenser, while the first indoor heat exchange is performed. In the control method of the air conditioner that causes the outdoor heat exchanger to function as an evaporator, in performing the cooling and dehumidifying operation, prior to the cooling and dehumidifying operation, depending on the state of refrigerant condensation in the outdoor heat exchanger. A method of controlling an air conditioner, characterized in that it is determined whether to perform a cooling operation for a predetermined time or to immediately start the cooling and dehumidifying operation without performing the cooling operation.   The state of refrigerant condensation in the outdoor heat exchanger is the operating state before performing the cooling and dehumidifying operation, the stop time of the compressor before performing the cooling and dehumidifying operation, or the outdoor heat when performing the cooling and dehumidifying operation. 2. The method of controlling an air conditioner according to claim 1, wherein the determination is made by taking into account at least one of the temperatures of the exchanger.   The cooling operation is performed for a predetermined time before the cooling dehumidifying operation is performed when the operation state before the cooling dehumidifying operation is a heating operation or a heating dehumidifying operation. Air conditioner control method.   When the operation state before performing the cooling and dehumidifying operation is an operation state other than the heating operation or the heating and dehumidifying operation, the stop time of the compressor is a predetermined time or more, and the temperature Tn of the outdoor heat exchanger is 3. The method of controlling an air conditioner according to claim 1, wherein the cooling operation is performed for a predetermined time before performing the cooling and dehumidifying operation when lower than a predetermined value.   During the cooling operation, when the temperature difference between the room temperature Tr and the temperature Te of the indoor heat exchanger becomes larger than a predetermined value, the cooling operation is stopped and the cooling dehumidification operation is started. The method for controlling an air conditioner according to any one of claims 1 to 4.   Even when the temperature difference between the room temperature Tr and the temperature Te of the indoor heat exchanger is smaller than a predetermined value, the cooling operation is stopped and the cooling and dehumidifying operation is performed when a predetermined time has elapsed in the cooling operation. 6. The method for controlling an air conditioner according to claim 5, wherein the control is started.   When the operation state before performing the cooling and dehumidifying operation is a heating operation or an operating state other than the heating and dehumidifying operation, if the predetermined time has not elapsed, the cooling operation is not performed. The method of controlling an air conditioner according to claim 4, wherein the dehumidifying operation is started.

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