JP2013053765A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner that can estimate an outside air temperature accurately without installing an outside air temperature sensor therein.SOLUTION: The air conditioner 31 includes: an outdoor heat exchanger 39; a temperature sensor 61 for measuring a temperature of the outdoor heat exchanger 39; an inflection point detection part 21 for detecting an inflection point Pi in a temperature change curve of the outdoor heat exchanger 39 measured by the temperature sensor 61 after shutdown of an air conditioning operation; a time measurement part 22 for measuring an elapsed time t between the inflection point Pi and a point where an inclination of the change curve is equal to a predetermined reference inclination X; a correction value setting part 23 for defining a temperature correction value α corresponding to a predetermined reference point P on the change curve based on the elapsed time t; and an outside air temperature estimation part 24 for correcting a temperature Tp of the outdoor heat exchanger 39 at the reference point P based on the temperature correction value α to define an estimation value Tf of the outside air temperature.

Description

  The present invention relates to an air conditioner.

  Conventionally, an air conditioner includes a dedicated outside temperature sensor (for example, a thermistor) for detecting the outside temperature. In the air conditioner, the mode at the start of operation (cooling operation or heating operation) is determined based on the outside air temperature detected by the outside air temperature sensor, or the necessity of the defrost operation is determined. However, since the detected value by the outside air temperature sensor is easily affected by the surrounding environment such as direct sunlight, snow cover, and freezing, the accuracy of the detected value may be lowered in some cases.

  Patent Document 1 and Patent Document 2 disclose an air conditioner for the purpose of predicting the outside air temperature without providing a dedicated outside air temperature sensor. In patent document 1, the temperature of the outdoor heat exchanger detected by the outdoor heat exchanger temperature sensor is corrected by the temperature detected by the compressor temperature sensor to predict the outdoor temperature. Moreover, in patent document 2, the temperature of the outdoor heat exchanger detected by the outdoor heat exchanger temperature sensor is corrected by a correction value determined based on the operating frequency of the compressor.

Japanese Patent Laid-Open No. 7-12080 JP 2001-272089 A

  However, in Patent Document 1 and Patent Document 2, since the influence of the surrounding environment after the operation is stopped is not taken into consideration, the predicted values of these outside air temperatures are likely to vary depending on the surrounding environment, and the accuracy is not necessarily good. I can't say that.

  Therefore, the present invention has been made to solve such problems, and an object thereof is to provide an air conditioner that can accurately predict the outside air temperature without providing an outside air temperature sensor.

  The air conditioner of the present invention includes an outdoor heat exchanger (39), a temperature sensor (61) for measuring the temperature of the outdoor heat exchanger (39), and the temperature sensor (61 The inflection point detection unit (21) for detecting the inflection point (Pi) in the temperature change curve of the outdoor heat exchanger (39) measured by (2), and the change curve from the inflection point (Pi) A time measurement unit (22) for measuring the elapsed time (t) until the inclination reaches a predetermined reference inclination (X), and a temperature correction corresponding to the predetermined reference point (P) on the change curve A correction value setting unit (23) that determines the value (α) based on the elapsed time (t), and the temperature (Tp) of the outdoor heat exchanger (39) at the reference point (P) is the temperature correction value ( an outside air temperature predicting unit (24) that determines a predicted value (Tf) of the outside air temperature by correcting based on α).

  In this configuration, after the air conditioning operation is stopped, the outside air temperature is predicted based on the temperature change curve of the outdoor heat exchanger (39) measured by the temperature sensor (61). The influence of the environment can be added to the predicted value.

  In this configuration, the outside air temperature is predicted based on the behavior of the temperature change after the inflection point (Pi). In the change curve, the behavior of the temperature change from immediately after the stop of the air conditioning operation to the inflection point (Pi) is not stable compared to the behavior of the temperature change after the inflection point (Pi). That is, the behavior of the temperature change after the inflection point (Pi) is more stable than the behavior of the temperature change before the inflection point (Pi). Therefore, based on the behavior of the temperature change after the inflection point (Pi) as in this configuration, that is, the elapsed time (t) from the inflection point (Pi) until the inclination of the change curve becomes the reference inclination (X). By determining the temperature correction value (α) and correcting the temperature (Tp) of the outdoor heat exchanger (39) at the reference point (P) based on the temperature correction value (α), the prediction accuracy is further increased. be able to.

  As described above, according to the present configuration, the influence of the environment around the outdoor unit (40) can be added to the prediction of the outside air temperature without providing the outside temperature sensor, so that the prediction accuracy of the outside temperature can be improved. Can do. This eliminates the need for a dedicated temperature sensor for measuring the outside air temperature, reduces the cost, and simplifies the assembly process of the air conditioner, thereby improving productivity.

  In the air conditioner, the reference point (P) is the inflection point (Pi), and the outside air temperature predicting unit (24) is the inflection point (Pi) of the outdoor heat exchanger (39). The predicted value (Tf) of the outside air temperature is preferably determined by correcting the temperature (Tp) based on the temperature correction value (α).

  As described above, in the change curve, the behavior of the temperature change after the inflection point (Pi) is more stable than the behavior of the temperature change before the inflection point (Pi). Therefore, when the reference point (P) to be corrected by the temperature correction value (α) is the inflection point (Pi), the point before the inflection point (Pi) is the reference point (P). Compared to, the prediction accuracy of the outside air temperature can be further increased.

  In the air conditioner, a storage unit (25) for storing the elapsed time (t) measured by the time measurement unit (22), and a plurality of elapsed times (t) stored in the storage unit (25). An elapsed time prediction unit (26) that determines an estimated elapsed time (ta) using the correction value setting unit (23), the temperature correction value (α) based on the estimated elapsed time (ta) May be determined.

  In this configuration, the temperature correction value (α) is determined based on the predicted elapsed time (ta) determined using the accumulated elapsed time (t), and thereafter, the elapsed time (t) Actual measurement can be omitted.

  Further, in the air conditioner, a storage unit (25) that accumulates the elapsed time (t) measured by the time measurement unit (22), and a plurality of elapsed times accumulated in the storage unit (25) ( an elapsed time predicting unit (26) that determines an estimated elapsed time (ta) using t), and an outdoor fan (40) that supplies the outdoor air to the outdoor heat exchanger (39), and further includes an air conditioning operation. After stopping, when the outside air is being supplied to the outdoor heat exchanger (39) by the outdoor fan (40), the correction value setting unit (23) is a temperature correction based on the predicted elapsed time (ta) When the outdoor air exchanger (39) is not supplying outside air to the outdoor heat exchanger (39) after the air conditioning operation is stopped after the value (α) is set, the time measuring unit (22) The elapsed time (t) is measured without using the elapsed time (ta), and the correction value setting unit (23) calculates the temperature based on the measured elapsed time (t). It may be set the correction value (alpha).

  In this configuration, after the air conditioning operation is stopped, when the outside air is supplied to the outdoor heat exchanger (39) by the outdoor fan (40), a certain amount of outside air passes through the outdoor heat exchanger (39). As a result, the temperature change of the outdoor heat exchanger (39) is less affected by the surrounding environment. Therefore, even if the temperature correction value (α) is determined based on the predicted elapsed time (ta), a sufficiently accurate predicted value (Tf) of the outside air temperature can be obtained.

  On the other hand, after the air conditioning operation is stopped, when the outdoor air blower (40) does not supply outdoor air to the outdoor heat exchanger (39), for example, the outdoor unit (40) is exposed to direct sunlight, wind and rain, etc. In this case, the influence of the surrounding environment on the outdoor heat exchanger (39) tends to vary. Therefore, in this case, it is preferable to measure the elapsed time (t), not the predicted value (ta), and determine the temperature correction value (α) based on the actually measured elapsed time (t).

  According to the present invention, it is possible to accurately predict the outside temperature without providing an outside temperature sensor.

It is a lineblock diagram showing the air harmony machine concerning one embodiment of the present invention. It is a control block diagram of the air conditioner. It is a flowchart which shows the example of control in the said air conditioner. It is a graph which shows the temperature change of the outdoor heat exchanger in the said air conditioner.

  Hereinafter, an air conditioner according to an embodiment of the present invention will be described with reference to the drawings.

<Structure of air conditioner>
As shown in FIG. 1, the air conditioner 31 includes a refrigerant circuit 32 and a control unit 20 that controls the refrigerant circuit 32. The refrigerant circuit 32 includes an indoor unit 33, an outdoor unit 34, a gas side communication pipe 35, and a liquid side communication pipe 36. The indoor unit 33 includes an indoor heat exchanger 37 and an indoor blower 38. The outdoor unit 34 includes an outdoor heat exchanger 39, an outdoor blower 40, a compressor 41, a four-way switching valve 42, an accumulator 43, an expansion valve 44, a gas side closing valve 45, and a liquid side closing valve 46. It has.

  In the outdoor unit 34, the discharge pipe 51 of the compressor 41 is connected to the first port of the four-way switching valve 42. The suction pipe 52 of the compressor 41 is connected to the outlet of the accumulator 43, and the suction pipe 53 connected to the inlet of the accumulator 43 is connected to the second port of the four-way switching valve 42. The third port of the four-way switching valve 42 is connected to one end 39 a of the outdoor heat exchanger 39, and the fourth port of the four-way switching valve 42 is connected to the gas side closing valve 45. The expansion valve 44 is provided between the other end 39 b of the outdoor heat exchanger 39 and the liquid side closing valve 46. In the indoor unit 33, one end 37 a of the indoor heat exchanger 37 is connected to the gas side communication pipe 35, and the other end 37 b of the indoor heat exchanger 37 is connected to the liquid side communication pipe 36. ing.

  As the indoor heat exchanger 37 and the outdoor heat exchanger 39, for example, a fin-and-tube heat exchanger or the like can be used. The indoor heat exchanger 37 exchanges heat between the refrigerant circulating in the refrigerant circuit 32 and the indoor air supplied by the indoor blower 38. The outdoor heat exchanger 39 exchanges heat between the refrigerant circulating in the refrigerant circuit 32 and the outdoor air supplied by the outdoor blower 40.

  By switching the route of the four-way switching valve 42, the cooling operation and the heating operation can be switched. In the path of the four-way switching valve 42 indicated by a solid line in FIG. 1, the first port and the third port communicate with each other, and the second port and the fourth port communicate with each other. When the four-way switching valve 42 is in a state indicated by a solid line, the air conditioner 31 performs a cooling operation. On the other hand, in the path of the four-way switching valve 42 indicated by a broken line in FIG. 1, the first port and the fourth port communicate with each other, and the second port and the third port communicate with each other. When the four-way switching valve 42 is in a state indicated by a broken line, the air conditioner 31 performs a heating operation.

  The air conditioner 31 has a plurality of temperature sensors (for example, thermistors) for controlling the operation thereof. The outdoor heat exchanger 39 is provided with an outdoor heat exchange temperature sensor 61 for detecting the temperature of the heat transfer tube (not shown). The outdoor heat exchanger temperature sensor 61 is provided in the vicinity of the middle between the end 39a and the end 39b of the outdoor heat exchanger 39.

  The discharge pipe 51 is provided with a discharge temperature sensor 62 for detecting the temperature of the refrigerant discharged from the compressor 41. The suction pipe 53 is provided with a suction temperature sensor 63 for detecting the temperature of the refrigerant sucked into the compressor 41. An unillustrated air intake port of the indoor unit 33 is provided with an intake temperature sensor 64 for detecting the intake temperature of air. The indoor heat exchanger 37 is provided with an indoor heat exchange temperature sensor 65 for detecting the temperature of the heat transfer tube (not shown). A temperature sensor 66 is provided at the end 39 b of the outdoor heat exchanger 39, and a temperature sensor 67 is provided at the end 37 b of the indoor heat exchanger 37. In the present embodiment, an outside air temperature sensor for detecting the outside air temperature is not provided.

  The control unit 20 is composed of a CPU, a memory, etc. (not shown). As shown in FIG. 2, the control unit 20 includes an inflection point detection unit 21, a time measurement unit 22, a correction value setting unit 23, an outside air temperature prediction unit 24, a storage unit 25, and an elapsed time prediction unit 26. And. The control unit 20 controls the compressor 41, the opening degree control of the expansion valve 44, the control of the four-way switching valve 42, the control of the outdoor blower 40 based on various data such as temperatures detected by the temperature sensors 61-67, The blower 38 and the like are controlled.

<Control of air conditioner>
Next, control of the air conditioner 31 will be described. FIG. 3 is a flowchart showing an example of control in the air conditioner 31. FIG. 4 is a graph showing a temperature change of the outdoor heat exchanger 39 in the air conditioner 31. In FIG. 4, a curve C1 in the graph is a curve showing a temperature change of the outdoor heat exchanger 39 during the heating operation and after the heating operation is stopped, and a curve C2 in the graph is a cooling operation and after the cooling operation is stopped. 4 is a curve showing a temperature change of the outdoor heat exchanger 39.

  In the storage unit 25 of the control unit 20, the reference inclination X and data shown in Table 1 are stored in advance. The reference inclination X is an inclination of a change curve (C1 or C2) that serves as a reference for determining the predicted value Tf of the outside air temperature. The reference slope X is the slope of the curve at a point located after the inflection point Pi among the points on the change curve.

  In the present embodiment, the reference gradient X is set to a value larger than zero in the case of heating operation, and is set to a value smaller than zero in the case of cooling operation. In both the heating operation and the cooling operation, the temperature of the outdoor heat exchanger 39 at the reference gradient X becomes the actual outdoor temperature Tr (the temperature indicated by the broken line in FIG. 4) as the reference gradient X is set to a value close to zero. ), The prediction accuracy of the predicted value Tf of the outside air temperature can be increased. On the other hand, since the elapsed time t can be shortened as the reference slope X is set to a value far from zero, that is, a value closer to the slope of the change curve at the inflection point Pi, the predicted outside air temperature Tf is determined. Can be shortened.

  In the present embodiment, the reference gradient X is set to a value close to zero. As a specific example, the reference slope X is preferably set to, for example, about 0.05 to 0.2 in the heating operation change curve C1, and in the cooling operation change curve C2, for example, −0. It is preferably set to about 05 to -0.2. The slope of the change curve in FIG. 4 is a value when the unit of time on the horizontal axis is “minute” and the unit of temperature on the vertical axis is “° C.”. The vertical axis of the graph shown in FIG. 4 may be an absolute value of the temperature T of the outdoor heat exchanger 39. For example, the relative value (ΔT ).

  The data shown in Table 1 is for determining the temperature correction value α. In this table, the elapsed time t from when the temperature T of the outdoor heat exchanger 39 reaches the inflection point Pi on the change curve (C1 or C2) until the change curve slope reaches the reference slope X, and the temperature correction. The value α is associated. Therefore, the temperature correction value α corresponding to the obtained elapsed time t is determined based on the correspondence shown in Table 1. Here, the inflection point Pi is a point where the sign of the second derivative of the function representing the change curve C1 or the change curve C2 changes before and after that.

(Control example 1)
First, the case where the air conditioner 31 is operated for heating will be described as an example. In this case, the four-way switching valve 42 in FIG. 1 is switched to the state indicated by the broken line, and the heating operation is started (step S1 in FIG. 3).

  In step S2, the control unit 20 determines whether or not the heating operation of the air conditioner 31 has been stopped. When the heating operation is continued, the control unit 20 continues to repeat the determination in step S2. When the heating operation is stopped, the control unit 20 performs the process of step S3.

  In step S3, the control unit 20 continues to detect the temperature of the outdoor heat exchanger 39 even after the heating operation is stopped. The temperature detection frequency is not particularly limited, but is set so that the curve data is smooth enough to detect the inflection point Pi of the change curve C1 in step S4 described later. The temperature data of the outdoor heat exchanger 39 is stored in the storage unit 25. The change curve of the temperature of the outdoor heat exchanger 39 during the heating operation and after the heating operation is stopped is, for example, a curve C1 shown in FIG.

  In step S4, the inflection point detection unit 21 of the control unit 20 determines whether or not the inflection point Pi appears in the temperature change curve C1 of the outdoor heat exchanger 39 after the heating operation is stopped. When the inflection point Pi is detected, the control unit 20 proceeds to step S5, and when the inflection point Pi is not detected, the inflection point detection unit 21 repeats the determination at step S4.

  In step S5, the time measuring unit 22 of the control unit 20 starts measuring the elapsed time t from when the inflection point Pi is detected.

  In step S6, the control unit 20 determines whether or not the slope of the change curve C1 has reached the reference slope X. When the inclination of the change curve C1 reaches the reference inclination X, the control unit 20 proceeds to step S7. When the inclination of the change curve C1 does not reach the reference inclination X, the control unit 20 determines in step S6. repeat. In this control example 1, the reference inclination X is set to 0.1, for example.

  In step S7, the correction value setting unit 23 of the control unit 20 determines the temperature correction value α based on the elapsed time t from the inflection point Pi required until the inclination of the change curve C1 reaches the reference inclination X. Specifically, for example, the temperature correction value α is determined based on the correspondence relationship with the elapsed time t shown in Table 1. That is, when the elapsed time t is less than 5 minutes, the temperature correction value α is 1 ° C., and when the elapsed time t is 5 minutes or more and less than 10 minutes, the temperature correction value α is 2 ° C. When the time t is 10 minutes or more and less than 15 minutes, the temperature correction value α is 3 ° C.

  In step S8, the outdoor temperature prediction unit 24 of the control unit 20 determines the predicted value Tf of the outdoor temperature by correcting the temperature Tp of the outdoor heat exchanger 39 at the inflection point Pi based on the temperature correction value α. In the control example 1, the predicted value Tf of the outside air temperature is calculated by adding the temperature correction value α to the temperature Tp of the outdoor heat exchanger 39 at the inflection point Pi. The predicted value Tf of the outside air temperature determined by the outside air temperature prediction unit 24 is stored in the storage unit 25.

  The predicted value Tf of the outside air temperature determined in this way is used, for example, to determine the mode (cooling or heating) at the start of the next operation, or to determine whether or not the defrost operation is necessary (step S9). In step S9, after determining the operation mode, necessity of defrost operation, etc. based on the predicted value Tf, the process proceeds to step S1 and the operation of the air conditioner 31 is started. The subsequent operation is the same as described above.

(Control example 2)
Next, control when the air conditioner 31 is in the cooling operation will be described. In this control example 2, the four-way switching valve 42 in FIG. 1 is switched to the state indicated by the solid line, and the cooling operation is started (step S1 in FIG. 3).

  In step S2 to step S7, the same control as in control example 1 is executed except that the heating operation is replaced with the cooling operation. In this control example 2, the reference inclination X is set to, for example, -0.1.

  In step S8, the outdoor temperature prediction unit 24 of the control unit 20 determines the predicted value Tf of the outdoor temperature by correcting the temperature Tp of the outdoor heat exchanger 39 at the inflection point Pi based on the temperature correction value α. In the control example 2, the predicted value Tf of the outside air temperature is a value obtained by subtracting the temperature correction value α from the temperature Tp of the outdoor heat exchanger 39 at the inflection point Pi. The predicted value Tf of the outside air temperature determined by the outside air temperature prediction unit 24 is stored in the storage unit 25. The following operations are the same as in Control Example 1.

(Control example 3)
When the air conditioner 31 is used for a certain period and the operation start and the operation stop are repeated a plurality of times, the following control of the air conditioner 31 may be executed.

  In this control example 3, the storage unit 25 accumulates a plurality of elapsed times t measured by the time measurement unit 22. In other words, the air conditioner 31 performs the control as described in the control example 1 or the control example 2 every time the operation stops, and the storage unit 25 accumulates the elapsed time t in each control each time. It will be done. Accordingly, the storage unit 25 accumulates the elapsed time t as many as the number of times that the control example 1 or the control example 2 is executed.

  The elapsed time prediction unit 26 determines a predicted elapsed time ta using a plurality of elapsed times t accumulated in the storage unit 25 as described later. That is, the elapsed time predicting unit 26 is based on the plurality of elapsed times t accumulated in the storage unit 25, the surrounding environment where the air conditioner 31 is installed, the characteristics of the air conditioner 31 (the pipe length of the refrigerant pipe). The trend of the elapsed time t reflecting the type of the heat exchanger, the type of refrigerant, etc.) is derived, and the predicted elapsed time ta is determined based on this trend. The correction value setting unit 23 determines the temperature correction value α based on the determined predicted elapsed time ta.

  Specifically, when n elapsed times t are accumulated in the storage unit 25, the elapsed time prediction unit 26 may determine an average value of the n elapsed times t as the predicted elapsed time ta. In addition, an average value of the latest several elapsed times t (for example, the latest three) among the n elapsed times t may be defined as the predicted elapsed time ta. In the latter case, since only the latest data is used, it is possible to obtain the predicted elapsed time ta that matches the season compared to the former.

  Using the predicted elapsed time ta obtained in this way, the elapsed time prediction unit 26 determines the temperature correction value α. Specifically, the elapsed time prediction unit 26 can determine the temperature correction value α by applying the predicted elapsed time ta to the corresponding relationship in Table 1 instead of the elapsed time t. Then, the outside air temperature prediction unit 24 determines the outside air temperature predicted value Tf by correcting the temperature Tp of the outdoor heat exchanger 39 at the inflection point Pi based on the temperature correction value α.

(Control example 4)
Further, in the air conditioner 31, the following control may be executed. In the control example 4, the air conditioner 31 is used for a certain period, and a plurality of elapsed times t are accumulated in the storage unit 25 as in the control example 3. Then, the elapsed time prediction unit 26 determines the predicted elapsed time ta using the plurality of elapsed times t accumulated in the storage unit 25. The flow for determining the predicted elapsed time ta is the same as in Control Example 3.

  In this control example 4, after the air conditioner 31 stops the air conditioning operation (cooling operation, heating operation, dehumidifying operation, etc.), the control example 3 and the control example 3 are as follows based on whether or not the outdoor blower 40 is operated. Performs different controls.

  After the air conditioning operation is stopped, when the outdoor air is supplied to the outdoor heat exchanger 39 by the outdoor fan 40, the correction value setting unit 23 determines the temperature correction value α based on the predicted elapsed time ta. In this case, the flow for determining the temperature correction value α is the same as in the control example 3 described above.

  On the other hand, after the air conditioning operation is stopped, when the outdoor fan 40 is not supplying outside air to the outdoor heat exchanger 39, the time measuring unit 22 measures the elapsed time t, and the correction value setting unit 23 measures. A temperature correction value α is determined based on the elapsed time t. In this case, the flow for determining the temperature correction value α is the same as in Control Example 1 or Control Example 2 described above.

<Outline of Embodiment>
The above embodiment is summarized as follows.

  In this embodiment, after the air-conditioning operation (cooling operation, heating operation, dehumidifying operation, etc.) is stopped, the outside air temperature is predicted based on the temperature change curve of the outdoor heat exchanger 39 measured by the temperature sensor 61. The influence of the environment around the outdoor unit 34 can be added to the predicted value.

  In the present embodiment, the outside air temperature is predicted based on the behavior of the temperature change after the inflection point Pi. In the change curve, the behavior of the temperature change from immediately after the stop of the air conditioning operation to the inflection point Pi is not stable compared to the behavior of the temperature change after the inflection point Pi. Therefore, the temperature correction value α is determined based on the behavior of the temperature change after the inflection point Pi as in this embodiment, that is, the elapsed time t from the inflection point Pi until the inclination of the change curve becomes the reference inclination X. By correcting the temperature Tp of the outdoor heat exchanger 39 at the reference point P based on the temperature correction value α, the prediction accuracy can be further increased.

  As described above, according to the present embodiment, the influence of the environment around the outdoor unit 34 can be added to the prediction of the outside air temperature without providing the outside air temperature sensor, so that the prediction accuracy of the outside temperature can be improved. it can. This eliminates the need for a dedicated temperature sensor for measuring the outside air temperature, reduces the cost, and simplifies the assembly process of the air conditioner, thereby improving productivity.

  In this embodiment, since the reference point P to be corrected by the temperature correction value α is the inflection point Pi, the outside air temperature is compared with the case where the point before the inflection point Pi is the reference point P. The prediction accuracy can be further increased.

  In the present embodiment, the temperature correction value α is determined based on the predicted elapsed time ta determined using the accumulated elapsed times t, and thereafter, the actual measurement of the elapsed time t is omitted. Can do.

  In the present embodiment, after the air-conditioning operation is stopped, when the outside air is supplied to the outdoor heat exchanger 39 by the outdoor blower 40, a certain amount of outside air continues to pass through the outdoor heat exchanger 39. Therefore, the temperature change of the outdoor heat exchanger 39 is less affected by the surrounding environment. Therefore, even if the temperature correction value α is determined based on the predicted elapsed time ta, it is possible to obtain the predicted value Tf of the outside temperature with sufficient accuracy.

  On the other hand, when the outdoor air blower 40 is not supplying outside air to the outdoor heat exchanger 39 after the air conditioning operation is stopped, for example, when the outdoor unit 34 is exposed to direct sunlight, wind and rain, the surrounding environment is Variations in the effect on the outdoor heat exchanger (39) are likely to occur. Therefore, in this case, the estimated elapsed time ta is not used, but the elapsed time t is actually measured, and the temperature correction value α is determined based on the actually measured elapsed time t.

<Other embodiments>
As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the meaning.

  In the embodiment, the case where the reference point P is the inflection point Pi has been described as an example, but the present invention is not limited to this. The reference point P may be a point when the air conditioner 31 stops the air conditioning operation in the graph of FIG. 4, for example, or may be an arbitrary point between this point and the inflection point Pi. . For example, when the point when the air conditioner 31 stops the air conditioning operation is set as the reference point P, the relationship between the temperature correction value α corresponding to the reference point P and the elapsed time t is in the form as shown in Table 1, for example. The temperature correction value α corresponding to the elapsed time t is determined based on this table. Then, the predicted value Tf of the outdoor temperature is determined by correcting the temperature Tp of the outdoor heat exchanger 39 at the reference point P based on the determined temperature correction value α.

  In the embodiment, the temperature correction value α is determined based on a table in which the relationship between the elapsed time t and the temperature correction value α is set in advance, and the predicted outside temperature Tf is set to the reference point P (for example, a variable value). The case where it is determined by adding the temperature correction value α to the temperature Tp of the outdoor heat exchanger 39 at the bending point Pi) (or subtracting the temperature correction value α from the temperature Tp) has been described as an example, but is not limited thereto. . The temperature correction value α may be determined based on the elapsed time t. For example, the temperature correction value α may be determined based on a function of elapsed time t stored in advance in the storage unit 25.

  Moreover, in the said embodiment, although the reference | standard inclination X illustrated the case where the temperature T of the outdoor heat exchanger 39 approached actual outdoor temperature, and was set to the inclination in the point where the inclination of the change curve C1 approached zero. However, the present invention is not limited to this. When the reference gradient X is a value close to zero, such as 0.1 illustrated in the embodiment, the temperature of the outdoor heat exchanger 39 when the reference gradient X is reached is also approaching the actual outside air temperature. Therefore, the predicted value Tf of the outside air temperature is high in accuracy. However, the reference inclination X does not necessarily have to be a value close to zero such as 0.1 exemplified in the above-described embodiment, for example, a value larger than 0.2 (during heating operation) or a value smaller than −0.2. (During cooling operation) may be set. In this case, the elapsed time t until the slope of the change curve reaches the reference slope X can be shortened.

(Reference example)
In the embodiment, the outdoor heat exchanger at the reference point P is used by using the temperature correction value α determined based on the elapsed time t from the inflection point Pi until the inclination of the change curve reaches a predetermined reference inclination X. The predicted value Tf of the outside air temperature is determined by correcting the temperature Tp of 39. On the other hand, for example, a mode in which data from the stop of the air conditioning operation to the inflection point is used for prediction of the outside air temperature is also conceivable. Specifically, for example, an elapsed time from when the air conditioning operation is stopped until the inflection point is reached is measured, a temperature correction value is determined based on the elapsed time, and an inflection is performed based on the determined temperature correction value, for example. Correct the temperature of the outdoor heat exchanger at the point.

  The control in the form of this reference example can be used, for example, after executing any one of the control examples 1 to 4 for a certain period and then switching to the control in the reference example with a certain condition as a trigger. For example, various conditions such as the number of times of execution of the control in any one of the control examples 1 to 4 and time can be adopted as the certain condition.

DESCRIPTION OF SYMBOLS 20 Control part 21 Inflection point detection part 22 Time measurement part 23 Correction value setting part 24 Outdoor temperature prediction part 25 Storage part 26 Elapsed time prediction part 31 Air conditioner 39 Outdoor heat exchanger 40 Outdoor blower 61 Outdoor heat exchanger temperature sensor 62 Discharge temperature sensor 63 Suction temperature sensor 64 Suction temperature sensor 65 Indoor heat exchanger temperature sensor α Temperature correction value P Reference point Pi Inflection point T Temperature of outdoor heat exchanger Tf Predicted value of outside air temperature Tp Reference point P (inflection point Pi ) Temperature of outdoor heat exchanger in Tr) Actual outside air temperature t Elapsed time ta Estimated elapsed time X Reference slope

Claims (4)

Outdoor heat exchanger (39),
A temperature sensor (61) for measuring the temperature of the outdoor heat exchanger (39);
An inflection point detector (21) for detecting an inflection point (Pi) in a temperature change curve of the outdoor heat exchanger (39) measured by the temperature sensor (61) after the air conditioning operation is stopped. ,
A time measurement unit (22) for measuring an elapsed time (t) from the inflection point (Pi) until the inclination of the change curve reaches a predetermined reference inclination (X);
A correction value setting unit (23) for determining a temperature correction value (α) corresponding to a predetermined reference point (P) on the change curve based on the elapsed time (t);
An outside air temperature prediction unit that determines a predicted value (Tf) of the outside air temperature by correcting the temperature (Tp) of the outdoor heat exchanger (39) at the reference point (P) based on the temperature correction value (α) ( 24) and an air conditioner. The reference point (P) is the inflection point (Pi),
The outside air temperature prediction unit (24) predicts the outside air temperature by correcting the temperature (Tp) of the outdoor heat exchanger (39) at the inflection point (Pi) based on the temperature correction value (α). The air conditioner according to claim 1, wherein the air conditioner defines a value (Tf). A storage unit (25) for accumulating the elapsed time (t) measured by the time measurement unit (22);
An elapsed time prediction unit (26) that determines a predicted elapsed time (ta) using a plurality of elapsed times (t) accumulated in the storage unit (25), and
The air conditioner according to claim 1 or 2, wherein the correction value setting unit (23) determines a temperature correction value (α) based on the predicted elapsed time (ta). A storage unit (25) for accumulating the elapsed time (t) measured by the time measurement unit (22);
An elapsed time prediction unit (26) that determines a predicted elapsed time (ta) using a plurality of elapsed times (t) accumulated in the storage unit (25);
An outdoor fan (40) for supplying outside air to the outdoor heat exchanger (39), and
After the air conditioning operation is stopped, when the outdoor fan (40) is supplying outside air to the outdoor heat exchanger (39), the correction value setting unit (23) sets the estimated elapsed time (ta). Based on the temperature correction value (α),
After the stop of the air conditioning operation, when the outdoor air is not supplied to the outdoor heat exchanger (39) by the outdoor fan (40), the time measuring unit (22) uses the predicted elapsed time (ta). The elapsed time (t) is actually measured, and the correction value setting unit (23) determines a temperature correction value (α) based on the actually measured elapsed time (t). Air conditioner.

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