JP2011117683A - Air conditioner and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control an air conditioner using an estimated value of an outside air temperature, while suppressing a number of installed sensors. <P>SOLUTION: In the air conditioner 1, a control circuit 10 controls an indoor blower 7, a four-way selector valve 2, an outdoor blower 6, and a compressor 16 based on the indoor temperature, the outside air temperature, etc. The air conditioner 1 obtains a reference temperature Ty, that is the estimated value of the outside air temperature, using the difference of detected temperatures immediately after and in one hour time after an operation stop of the outdoor heat exchanger thermistor 17 for detecting a temperature of the compressor 16, without installing a thermistor for detecting a temperature of an outdoor heat exchanger 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air conditioner, and more particularly to an air conditioner that operates by predicting an outside air temperature and a control method thereof.

  Some conventional air conditioners detect the outside air temperature and control the operation based on the temperature. The outside air temperature may be directly detected by a dedicated sensor for detecting the outside air temperature attached to the outdoor unit, or as described in Patent Document 1 (Japanese Patent Laid-Open No. 7-12080). In some cases, the temperature is estimated based on the temperature detected by a sensor that detects the temperature of a heat exchanger provided in the outdoor unit.

Japanese Patent Laid-Open No. 7-12080

  In addition, in the conventional air conditioner, when the number of mounted sensors is increased, the physical structure is complicated accordingly, which leads to an increase in man-hours and costs of manufacturing work.

  Here, as described in Patent Document 1, the temperature of the compressor installed in the outdoor unit is detected, and the temperature of the dedicated sensor or heat exchanger described above is determined by estimating the outside air temperature based on the detected temperature. It is also conceivable to omit the sensor to be detected.

  However, although the temperature of the compressor gradually approaches the outside air temperature after the operation is stopped, it takes several hours to coincide with the outside air temperature. In other words, depending on the operating conditions, the compressor temperature does not match the outside air temperature for a considerable time. From this, when the outside air temperature is estimated based on the detected temperature of the sensor that detects the temperature of the compressor, the time when the compressor temperature approaches the outside air temperature after the operation of the compressor is stopped has elapsed. Until then, it is assumed that the outside air temperature cannot be predicted. On the other hand, since it is also assumed that restart of operation is instructed immediately after the operation is stopped, it is required to estimate the accurate outside air temperature in the shortest possible time.

  As described above, in the conventional air conditioner, if it is attempted to reduce the number of sensors to be mounted, it has not been possible to cope with a situation in which the operation is resumed immediately after the operation of the compressor is stopped.

  The present invention has been conceived in view of such a situation, and an object of the present invention is to enable control using an estimated value of the outside air temperature while suppressing the number of sensors mounted in the air conditioner. is there.

  An air conditioner according to the present invention is an air conditioner including a compressor, an outdoor heat exchanger, and an indoor heat exchanger, and the compressor is installed outside, compresses a refrigerant, and compresses the refrigerant. Detecting means for detecting the temperature of the compressor after the refrigerant compression operation is stopped, the mode of change of the temperature after the compressor compression operation is stopped, and the estimation of the difference between the compressor temperature and the outside air temperature An estimated value for obtaining an estimated value of the outside air temperature based on the storage means for storing the correspondence relationship with the value and the temperature detection result and the correspondence relationship by the detection means at a plurality of times after the compression operation of the compressor is stopped Acquisition means.

  Further, in the air conditioner of the present invention, the detection means includes a first temperature that is a temperature immediately after the refrigerant compression operation of the compressor is stopped as a temperature after the refrigerant compression operation is stopped, and a refrigerant refrigerant of the compressor. A second temperature which is a temperature after a certain time from the stop of the compression operation, and the storage means detects the difference between the temperature of the compressor detected by the detection means at different times, and the detected temperature and the outside air temperature. The correspondence relationship with the estimated difference value is stored, and the estimated value acquiring means acquires the estimated value of the difference between the first temperature and the second temperature detected by the detecting means and the difference between the outside air temperature based on the corresponding relationship. And the estimated value of outside temperature is acquired by calculating the sum of the estimated value of the difference with the said outside temperature, and 1st temperature.

  In the air conditioner of the present invention, the detection means further detects a third temperature, which is the temperature of the compressor, after a predetermined time has elapsed since the second temperature was detected, and the estimated value acquisition means When the difference between the first temperature and the second temperature is equal to or higher than a certain temperature, an estimated value of the difference between the outside temperature and the second temperature and the third temperature is acquired based on the difference between the second temperature and the third temperature, and the correspondence relationship; The estimated value of the outside air temperature is obtained by calculating the sum of the estimated value of the difference between the outside air temperatures and the second temperature.

  An air conditioner control method according to the present invention is an air conditioner control method including a compressor that is installed outdoors and compresses a refrigerant, an outdoor heat exchanger, and an indoor heat exchanger, The step of detecting the temperature of the compressor after the refrigerant compression operation is stopped, the mode of change of the temperature after the compressor compression operation is stopped with time, and the estimation of the difference between the compressor temperature and the outside air temperature. A step of storing a correspondence relationship with the value, and a step of obtaining an estimated value of the outside air temperature based on the temperature and the correspondence relationship detected at a plurality of times after the compression operation of the compressor is stopped.

  According to the present invention, the temperature of the compressor at a plurality of times after the refrigerant compression operation is stopped is detected, the amount of change in temperature for a certain time, the time required for a certain amount of temperature to change, etc. The estimated value of the outside air temperature can be acquired by acquiring the temperature change mode and referring to the correspondence stored in the storage means.

  Thereby, after the operation of the compressor is stopped, the detection output of the detection means for detecting the temperature of the compressor provided in the general air conditioner without waiting for the temperature of the compressor to decrease to the outside air temperature. By using, an estimated value of the outside air temperature can be acquired.

  Accordingly, it is possible to obtain an estimated value of the outside air temperature without providing a dedicated sensor for detecting the outside air temperature or a sensor for detecting the temperature of the heat exchanger of the outdoor unit.

It is a figure which shows typically the whole structure of the air conditioner which is one embodiment of this invention. It is a figure which shows the circuit structural example of the air conditioner of FIG. It is a figure which shows the outdoor temperature, the outdoor heat exchanger temperature, and the compressor temperature with respect to the elapsed time from the operation stop of the compressor of the air conditioner of FIG. It is a flowchart of the reference temperature calculation process which the control circuit of the air conditioner of FIG. 1 performs.

Hereinafter, an air conditioner according to an embodiment of the present invention will be described with reference to the drawings.
[Overall configuration of air conditioner]
FIG. 1 is a diagram schematically showing an overall configuration of an air conditioner according to an embodiment of the present invention.

  The air conditioner 1 includes a compressor 16, a four-way switching valve 2, an outdoor heat exchanger 3, a decompressor 4, and an indoor heat exchanger 5. In the air conditioner 1, the connection mode of piping is changed by switching the four-way switching valve 2.

  In the air conditioner 1, a path including the outdoor heat exchanger 3, the compressor 16, and the indoor heat exchanger 5 is connected by piping. In the route, the refrigerant circulates. The compressor 16 compresses the refrigerant sent from the outdoor heat exchanger 3 or the indoor heat exchanger 5.

  The air conditioner 1 further includes an outdoor fan 6, an indoor fan 7, a room temperature thermistor 8, and a compressor thermistor 17. The outdoor fan 6 is used for heat exchange of the outdoor heat exchanger 3. The indoor blower 7 is used for heat exchange of the indoor heat exchanger 5. The room temperature thermistor 8 detects the room temperature. The compressor thermistor 17 detects the temperature of the compressor 16.

[Piping connection mode]
In the air conditioner 1, during the cooling operation, the four-way switching valve 2 is switched so that the compressor 16 → the four-way switching valve 2 → the outdoor heat exchanger 3 → the pressure reducing device 4 → the indoor heat exchanger 5 → the four-way switching valve 2 → Pipe connection is made so that a refrigerant flow path (cooling cycle) circulating in the order of the compressor 16 is formed.

  That is, during the cooling operation, the high-temperature and high-pressure refrigerant discharged from the compressor 16 is condensed and liquefied by exchanging heat with the outside air in the outdoor heat exchanger 3, and further depressurized by the decompressor 4 to be low-temperature and low-pressure gas-liquid. After becoming a two-phase state, it flows into the indoor heat exchanger 5. In the indoor heat exchanger 5, the gas-liquid two-phase refrigerant is evaporated and vaporized by heat exchange with room air, and becomes low-temperature and low-pressure steam. The indoor air is cooled by this heat exchange, returned to the room, and used for indoor cooling. The low-temperature and low-pressure refrigerant vapor flowing out of the indoor heat exchanger 5 returns to the compressor 16 again, and this cycle is repeated to cool the room.

  On the other hand, during the heating operation, there is a refrigerant flow path (heating cycle) that circulates in the order of the compressor 16 → the four-way switching valve 2 → the indoor heat exchanger 5 → the decompressor 4 → the outdoor heat exchanger 3 → the four-way switching valve 2 → the compressor 16. Piping is connected to make up.

  During the heating operation, the high-temperature and high-pressure refrigerant discharged from the compressor 16 is condensed and liquefied by exchanging heat with the indoor air in the indoor heat exchanger 5, that is, releasing heat to be used for indoor heating. become. Then, the low-temperature and low-pressure gas-liquid two-phase refrigerant decompressed by the decompressor 4 is evaporated and vaporized by exchanging heat with the outside air in the outdoor heat exchanger 3, that is, absorbing the outdoor heat and again. Returning to the compressor 16, the room is heated by repeating this cycle.

[Circuit configuration of air conditioner]
FIG. 2 is a diagram illustrating a circuit configuration example of the air conditioner 1 according to the present embodiment.

  The air conditioner 1 controls the indoor blower 7, the four-way switching valve 2, the outdoor blower 6, and the compressor 16 based on the indoor temperature, the outside air temperature, and the like, and the supply of power to the compressor 16. Inverter control unit 18 that operates and an operation unit 20 that receives and receives input of information from the user.

  The control circuit 10 includes a microcomputer and also includes a memory 10A that stores various information. The operation unit 20 includes a button provided on the main body of the indoor unit of the air conditioner 1, a remote controller (hereinafter referred to as “remote controller”) provided separately from the indoor unit, and between the remote controller and the control circuit 10. A communication unit for transmitting and receiving information wirelessly by infrared rays or the like is included.

  The air conditioner 1 includes a power plug 11 for receiving power supply from the outside. In the air conditioner 1, the indoor blower 7, the four-way switching valve 2, the outdoor blower 6, the compressor 16, and the control circuit 10 are connected in parallel to the power plug 11.

  The air conditioner 1 further includes an indoor fan relay switch 12, a four-way selector valve relay switch 13, and an outdoor fan relay switch 14, which are controlled to be turned on and off by the output of the control circuit 10. Is done.

[Operations during operation of the air conditioner]
In the air conditioner 1, at the start of operation, operation control (mode determination at start of operation, overload control, etc.) is performed using the reference temperature Ty instead of the outside air temperature.

  The reference temperature Ty is obtained according to the following equation (1). In Equation (1), the temperature T1 is a temperature detected by the compressor thermistor 17 immediately after the end of the previous operation, and the temperature difference Tx is a value stored in the memory 10A.

Ty = T1-Tx (1)
A method for calculating the reference temperature Ty will be described later.

[Heating / cooling judgment]
In the air conditioner 1, when starting the automatic operation, the reference temperature Ty is determined at the start, and it is determined whether to perform the heating operation or the cooling operation based on the determined value of the reference temperature Ty. . For example, when the temperature is lower than 18 ° C., the heating operation is performed, and when the temperature is 18 ° C. or higher, the cooling operation is performed.

  In the heating operation, all the relay switches 12 to 14 are turned on by the control circuit 10, and an instruction to start energization of the compressor 16 is issued to the inverter control unit 18, and the heating cycle described above is performed. Composed. Thereby, the compressor 16 starts operation, and the discharged refrigerant is sent to the indoor heat exchanger 5. This refrigerant is condensed and liquefied in the indoor heat exchanger 5 and warms the indoor air blown from the indoor blower 7. The condensate is decompressed by the decompressor 4 and then evaporated and vaporized by exchanging heat with the outdoor air by the outdoor heat exchanger 3, and this refrigerant vapor returns to the compressor 16 again, and this cycle is repeated thereafter. become. The control circuit 10 controls such a heating operation so as to reach the set room temperature based on the room temperature detected by the room temperature thermistor 8.

  On the other hand, in the cooling operation, only the relay switch 13 in the relay switch described above is not turned on, and a cooling cycle is configured.

[Calculation of reference temperature]
Next, calculation of the reference temperature Ty in the air conditioner 1 of the present embodiment will be described.

  In the air conditioner 1 of this Embodiment, the thermistor which detects the temperature of the outdoor heat exchanger 3 provided in the general air conditioner is not provided. In the air conditioner 1, by using the reference temperature Ty, the outside air temperature is estimated without using the temperature of the outdoor heat exchanger 3, and control is performed.

  In the air conditioner 1, when the cooling operation or the heating operation is stopped, for example, as shown in FIG. 3, the detected temperature of the compressor 16 gradually approaches the outside air temperature.

  In FIG. 3, the outdoor temperature, the temperature of the outdoor heat exchanger 3 (outdoor heat exchange temperature), and the compressor 16 with respect to the elapsed time from the shutdown of the compressor 16 of the air conditioner 1 measured experimentally. The temperature (compressor temperature) is indicated. Here, the temperature of the compressor 16 is a temperature detected by the compressor thermistor 17. The outdoor air temperature and the temperature of the outdoor heat exchanger 3 are temperatures detected by a thermistor provided separately for the air conditioner 1.

  FIG. 3 shows an example in which the outside air temperature is 30 ° C. The compressor temperature is about 100 ° C. immediately after the operation is stopped, but gradually approaches the outside air temperature and becomes equal to the outside air temperature after about 7 o'clock. In other words, if it is attempted to execute the control by regarding the value of the compressor temperature as the outside air temperature, the outside air temperature can be used only after 7 hours after the operation is stopped.

  In the present embodiment, after the operation of the compressor 16 is stopped, the temperature of the compressor 16 is detected after a certain time, and the difference from the temperature immediately after the operation is stopped is calculated. Based on the temperature difference, A temperature difference Tx between the compressor 16 and the outside air temperature is estimated.

  Specifically, in the air conditioner 1, the measured temperature of the compressor 16 is measured immediately after the operation and 1 hour after the operation is stopped. Then, the temperature measured immediately after the operation is stopped is stored in the memory 10A as T1, and the temperature measured one hour after the operation is stopped as T2.

  Then, a value of “T1−T2” is calculated, and the value is converted into an estimated value of a difference from the outside air temperature as shown in Table 1. The temperature change T11 in Table 1 is “T1-T2”. Table 1 is obtained for the air conditioner 1 in advance, and information specifying Table 1 is stored in the memory 10A.

  Then, the reference temperature Ty is obtained by adding the estimated value of the difference between the temperature change T11 and the outside air temperature obtained from Table 1 to the temperature T1 of the compressor 16 immediately after the shutdown. That is, the estimated value obtained from Table 1 is the estimated value of the temperature difference Tx described above, and the reference temperature Ty is obtained according to the following equation (2).

Ty = T1- (estimated value of Tx) (2)
In Table 1, estimated values for the case where the difference between T1 and T2 is from 0 ° C. to 20 ° C. are shown. In the present embodiment, when the difference between T1 and T2 exceeds 20 ° C., the error when Ty is regarded as the outside air temperature becomes large, and the outside air temperature is not estimated. In such a case, the temperature T3 of the compressor 16 is measured after one hour has elapsed since the operation stop, and the difference between T2 and T3 is set to T11 in Table 1, with reference to Table 1, the estimated value and the reference temperature. Ty may be obtained. In this case, the reference temperature is obtained according to the following equation (3).

Ty = T2− (estimated value of Tx) (3)
[Reference temperature calculation processing]
Hereinafter, the content of the process for calculating the reference temperature (reference temperature calculation process) by the control circuit 10 will be described with reference to FIG. 4 which is a flowchart of the process.

  In the reference temperature calculation process, first, in step S10, the control circuit 10 determines whether or not the operation of the compressor 16 has been stopped by inputting a cooling operation or heating operation stop instruction from the operation unit 20 or the like. . Specifically, it is determined whether or not the transmission of power from the inverter control unit 18 to the compressor 16 is stopped by the input of the above instruction or the like. Then, if the control circuit 10 determines that it has been stopped, it proceeds to step S20.

  In step S20, the control circuit 10 stores the detected temperature of the compressor thermistor 17 in the memory 10A as the temperature T1, and advances the process to step S30.

  In step S30, the control circuit 10 determines whether or not the operation of the compressor 16 continues to be stopped after detecting the operation stop in step S10. If so, the process proceeds to step S40. When it is determined that this is not the case (that is, driving has been resumed), the process returns to step S10.

  In step S40, the control circuit 10 determines whether or not one hour has elapsed since the operation stop was detected in step S10. If it is determined that the time has elapsed, the control circuit 10 proceeds to step S50 and determines that it has not yet elapsed. Then, the process returns to step S30.

  In step S50, the control circuit 10 stores the detected temperature of the compressor thermistor 17 in the memory 10A as the temperature T2, and advances the process to step S60.

  In step S60, the control circuit 10 determines whether or not the difference between T1 and T2 is equal to or less than 20 (° C.). If so, the control circuit 10 proceeds to step S70, otherwise (that is, 20 ° C.). If it is determined that the process is over, the process is terminated.

  In step S70, the control circuit 10 obtains T11 in accordance with the following equation (4), and uses T11 to refer to the above-described Table 1 to estimate the difference between the outside air temperature (the outside air temperature and the compressor 16). (Estimated value of temperature difference Tx) is obtained, and the process proceeds to step S80.

T11 = T1-T2 (4)
In step S80, the control circuit 10 obtains the reference temperature Ty from T1 and the estimated value obtained in step S70 according to the equation (1), stores the reference temperature Ty in the memory 10A, and ends the process.

  According to the present embodiment described above, in the air conditioner 1, the temperature of the compressor 16 is detected immediately after the compressor 16 is stopped and after a predetermined time, and the temperature difference between these is calculated and based on the temperature difference. Thus, the temperature difference Tx between the compressor 16 and the outside air temperature when the operation is stopped is estimated. Then, a reference temperature Ty that is an estimated value of the outside air temperature is calculated using the calculated estimated value Tx of the temperature difference. Then, the operation of the air conditioner 1 is controlled using the reference temperature Ty.

  Thereby, without providing the thermistor for detecting the temperature of the outdoor heat exchanger 3, the reference temperature Ty which is an estimated value of the outside air temperature (using the detected temperature immediately after the compressor 16 is stopped and 1 hour after the shutdown). Can be obtained and used for control.

  The fixed time is not limited to “1 hour”. It is conceivable that the characteristics of the temperature drop after the shutdown of the compressor greatly vary depending on the weight or structure of the compressor situation or the structure of the soundproofing material around the compressor. For this reason, it is considered that the relationship between the estimated value and the temperature that has changed over a certain period of time and the certain period of time as shown in Table 1 is set for each configuration of the air conditioner 1.

  Further, in the present embodiment, the temperature of the compressor 16 is detected immediately after the operation is stopped and after a certain period of time, that is, at two predetermined timings, as changes in the temperature of the compressor 16 after the operation is stopped. Thus, the reference temperature Ty is acquired. In addition, the aspect of the temperature detection in several time in this invention is not limited to this.

  You may detect the temperature of the compressor 16 for every predetermined time (shorter than fixed time) immediately after a driving | operation stop. Then, based on these temperature detection results, a time until the temperature of the compressor 16 decreases by a certain amount of temperature may be calculated, and the reference temperature Ty may be acquired based on the time. In this case, instead of Table 1 that defines the correspondence between “T11 (temperature change amount of the compressor 16 over a certain period of time)” and “estimated value of the difference between the outside air temperatures”, “the operation stop in the compressor 16” The reference temperature Ty is acquired by using information defining the correspondence between the “time required for a certain amount of temperature to drop immediately after” and the “estimated value of the difference from the outside air temperature”. At this time, the estimated value of the difference from the outside air temperature increases as the time required for the temperature of the certain amount to decrease immediately after the operation is stopped is shorter.

  Note that the reference temperature Ty cannot be acquired during the initial operation of the air conditioner 1. For this reason, in such a case, the air conditioner 1 does not estimate the outside air temperature, and performs control assuming that the outside air temperature is high (for example, 45 ° C.).

[Overload control judgment]
In the air conditioner 1, overload control determination processing is performed using the reference temperature Ty described above.

  In the overload control determination process, the temperature of the electrical component of the outdoor unit of the air conditioner 1 is estimated using the reference temperature Ty that is an estimated value of the outside air temperature. That is, when the reference temperature Ty is high, it is assumed that the temperature of the electrical components of the outdoor unit is also raised to some extent. Therefore, the current value of the alternating current that flows through the electrical components of the entire outdoor unit is lower than when the temperature is low. Is limited. Thereby, the further temperature rise of an electrical component can be suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Air conditioner, 2 Four way switching valve, 3 Outdoor heat exchanger, 4 Pressure reducer, 5 Indoor heat exchanger, 6 Outdoor blower, 7 Indoor blower, 8 Room temperature thermistor, 10 Control circuit, 10A memory, 11 Power plug, 12 Relay switch for indoor blower, 13 Relay switch for four-way switching valve, 14 Relay switch for outdoor blower, 16 compressor, 17 compressor thermistor, 18 inverter control unit, 20 operation unit.

Claims (4)

An air conditioner including a compressor, an outdoor heat exchanger, and an indoor heat exchanger,
The compressor is installed outdoors, compresses the refrigerant,
Detecting means for detecting the temperature of the compressor after the refrigerant compression operation is stopped;
Storage means for storing a correspondence relationship between an aspect of a change with time of temperature after the compression operation of the compressor is stopped and an estimated value of a difference between the temperature of the compressor and an outside air temperature;
An air conditioner further comprising: an estimated value acquisition means for acquiring an estimated value of an outside air temperature based on the temperature detection result by the detection means and the correspondence relationship at a plurality of times after the compression operation of the compressor is stopped. Machine. The detection means has a constant temperature from the stop of the refrigerant compression operation of the compressor, the first temperature which is the temperature immediately after the refrigerant compression operation of the compressor is stopped, as the temperature after the refrigerant compression operation is stopped. Detecting a second temperature which is a temperature after time,
The storage means stores a correspondence relationship between a difference in temperature of the compressor detected by the detection means at different times and an estimated value of the difference between the detected temperature and the outside air temperature,
The estimated value acquiring means acquires an estimated value of the difference between the outside temperature based on the difference between the first temperature and the second temperature detected by the detecting means and the correspondence relationship, and the outside temperature The air conditioner according to claim 1, wherein the estimated value of the outside air temperature is obtained by calculating the sum of the estimated value of the difference between the first temperature and the first temperature. The detection means further detects a third temperature, which is a temperature of the compressor, after the predetermined time has elapsed after detecting the second temperature,
When the difference between the first temperature and the second temperature is equal to or higher than a certain temperature, the estimated value acquisition unit is based on the difference between the second temperature and the third temperature and the correspondence relationship. The estimated value of the outside air temperature is obtained by obtaining an estimated value of the difference from the outside air temperature and calculating the sum of the estimated value of the difference between the outside air temperature and the second temperature. Air conditioner. A control method for an air conditioner comprising a compressor that is installed outdoors and compresses a refrigerant, an outdoor heat exchanger, and an indoor heat exchanger,
Detecting the temperature of the compressor after stopping the refrigerant compression operation;
Storing a correspondence relationship between an aspect of a change with time of temperature after stopping the compression operation of the compressor and an estimated value of a difference between the temperature of the compressor and an outside air temperature;
A method for controlling an air conditioner, comprising: obtaining an estimated value of an outside air temperature based on the detected temperature and the correspondence relationship at a plurality of times after the compression operation of the compressor is stopped.

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