JP2006258340A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-conditioner with an outdoor unit where an outside air temperature is estimated without using an outside air temperature sensor. <P>SOLUTION: The air-conditioner operates an outdoor fan for a certain time before starting a compressor or after stopping the compressor, promotes the pressure equalization of refrigerant in an indoor/outdoor unit, and updates the temperature of an outdoor heat exchanger at starting the compressor, as an outside air temperature. Thus, the temperature of the outdoor heat exchanger can approach the outside air temperature in a short time and the outside air temperature can be updated each time when starting the compressor. Besides, a correction value is introduced depending on the outside air temperature or the updating is prohibited depending on conditions when stopping the compressor, thereby increasing detecting accuracy and reducing detecting errors. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner that performs operation control by predicting an outside air temperature.

  Conventionally, this type of air conditioner performs operation control by estimating the outdoor air temperature from the outdoor heat exchanger temperature by the outdoor heat exchanger temperature sensor (see, for example, Patent Document 1).

FIG. 7 shows a correlation diagram between the temperature of the outdoor heat exchanger of the conventional air conditioner described in Patent Document 1 and the elapsed time from the shutdown.
Japanese Patent Laid-Open No. 7-12080

  However, since the conventional method requires a long time from when the operation is stopped until the outdoor heat exchanger temperature approaches the outside air temperature, the outside air temperature during the previous operation is used as it is, and the outside air temperature changes. However, there was a problem that the outside temperature could not be reestimated and updated.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide an air conditioner that can update the outside air temperature every time the compressor is started without using an outside air temperature sensor. And

  In order to solve the conventional problem, the air conditioner of the present invention operates the outdoor fan for a predetermined time before starting the compressor or after stopping the compressor, and sets the outdoor heat exchanger temperature at the time of starting the compressor to the outside air temperature. Is updated under special conditions.

  As a result, the outdoor heat exchanger temperature and the outdoor air temperature can be brought close to each other in a short time, and it is possible to update the outdoor air temperature every time the compressor is started. It is possible to avoid false detection and improve detection accuracy.

  Since the air conditioner of the present invention can estimate the outside air temperature with higher detection accuracy than the conventional one without using the outside air temperature sensor, it includes a sensor, a holder, and electrical components while maintaining the comfort of the user environment. Parts cost can be reduced. In addition, since a complicated calculation formula is not used, software can be simplified, and software can be shared with other models, so that design costs and component costs can be reduced.

  In the first aspect of the invention, when the previous estimated outside air temperature is equal to or higher than (Tc) in the heating operation, a predetermined value is used when estimating the outside air temperature from the outdoor heat exchanger temperature at the time of starting the compressor after the outdoor fan operation ends. By adding the correction value (ΔT1), it is possible to improve the detection accuracy.

  According to a second aspect of the present invention, when the previous estimated outside air temperature is equal to or lower than (Td) in the cooling operation, a predetermined value is used when estimating the outside air temperature from the outdoor heat exchanger temperature at the time of starting the compressor after the outdoor fan operation ends. By adding the correction value (ΔT2), it is possible to increase the detection accuracy.

The third aspect of the invention estimates the outdoor air temperature from the outdoor heat exchanger temperature at the time of starting the compressor after the outdoor fan operation when the change rate of the outdoor heat exchanger temperature during the outdoor fan operation is large after the compressor is stopped. The detection accuracy can be improved by adding a predetermined correction value (ΔT3).

  In the fourth aspect of the invention, when continuous operation is performed with mode change, such as from cooling (dehumidification) to heating or vice versa, the outdoor heat exchanger temperature changes greatly. It is possible to prevent erroneous detection of the outside air temperature by not updating the outside air temperature even when it is started.

  In the fifth aspect of the invention, when the compressor is continuously stopped within a predetermined time (td), it can be considered that the outside air temperature has not changed. Therefore, as an exception, even when the compressor is stopped and restarted. By not updating the outside air temperature, it is possible to accurately detect the outside air temperature without being affected by fluctuations in the outdoor heat exchanger temperature.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a flowchart of outdoor temperature prediction control of an air conditioner according to the first embodiment of the present invention, FIG. 2 is a conceptual diagram of a change with time in the outdoor heat exchanger temperature during heating operation, and FIG. FIG. 4 is a conceptual diagram of the time-dependent change of the outdoor heat exchanger temperature during operation, FIG. 4 is a correlation diagram of the rate of change of the outdoor heat exchanger temperature, the difference between the outdoor air temperature and the outdoor heat exchanger temperature, and FIG. FIG. 6 is a time chart of the outside temperature estimation update permission and the compressor ON / OFF time chart when the compressor is ON / OFF.

In FIG. 1, in ST01, the outdoor fan is operated for a predetermined time (Ta) before the compressor is started. Thereafter, in ST02, the outside air temperature Tout estimated from the outdoor heat exchanger temperature is updated.
Next, the flow branches depending on the operation mode of the air conditioner. In the heating operation (ST11), if the previous estimated outside air temperature Tout is equal to or higher than the predetermined temperature Tc in ST12, the process proceeds to ST13, a predetermined correction value ΔT1 is added to the estimated outside air temperature Tout, and the process proceeds to ST31.
In the cooling operation (ST21), if the previous estimated outside air temperature Tout is equal to or lower than the predetermined temperature Td in ST22, the process proceeds to ST23, and a predetermined correction value ΔT2 is added to the estimated outside air temperature Tout, and the process proceeds to ST31.
When the condition is not satisfied in each step, the correction value is not added to the estimated outside air temperature Tout, and the process proceeds to ST31.
In ST31, when the temperature change rate ΔTout / Δt of the outdoor heat exchanger temperature is large, the process proceeds to ST32, and a correction value ΔT3 is added to the estimated outside air temperature Tout, and when it is small, a correction value is added to the estimated outside air temperature Tout. Without adding, proceed to ST03.
The outside air temperature Tout is estimated by the flow as described above, and the compressor operation is started (restarted) under the optimum operation condition in ST03 taking the condition into consideration, and the process proceeds to ST04.

In ST04, it is confirmed whether or not the compressor is stopped. If the compressor is not stopped, if the continuous operation time of the compressor reaches tc in ST05, the process proceeds to ST06, and the compressor is forcibly stopped. ST07 Then, the outdoor fan is operated for a predetermined time (tb) to promote pressure equalization.
If the compressor stops before tc (ST04), the process proceeds to ST41.

In ST41, when the stop of the compressor is due to the mode change, the compressor is not regarded as being stopped and the process returns to ST03 again. If the stop of the compressor is not due to a mode change, the time from the start of the compressor is determined in ST51, and if it is less than the predetermined time (td), the compressor is not regarded as being stopped and the process returns to ST03 again. Otherwise, the process proceeds to ST07, and the outdoor fan is operated for a predetermined time (tb) to promote equalization.

  In ST07, after operating the outdoor fan for tb to promote pressure equalization, if the operation of the air conditioner continues, the process returns to ST01, and the estimated outside air temperature Tout is updated according to the situation.

  In the present embodiment, a method is employed in which the outdoor heat exchanger temperature is estimated to be equal to the outdoor air temperature Tout.

  FIG. 2 shows a change in outdoor heat exchanger temperature during outdoor fan operation when the outside air temperature is equal to or higher than Tc during heating operation. Since the temperature of the outdoor heat exchanger decreases during heating operation, the outdoor air temperature and the outdoor heat exchanger temperature are significantly different from each other. However, by operating the outdoor fan after the compressor is stopped, the outdoor air temperature and the outdoor heat exchanger temperature are reduced. Approximate. However, the value fluctuates up and down with respect to the actual outside air temperature in the middle stage. Therefore, a value closer to the actual outdoor air temperature is obtained by performing correction by adding a predetermined correction value (ΔT1) to the outdoor heat exchanger temperature at the end of the outdoor fan operation, that is, the estimated outdoor air temperature Tout.

  FIG. 3 shows a change in outdoor heat exchanger temperature during outdoor fan operation when the outside air temperature is equal to or lower than Td during cooling operation. Since the temperature of the outdoor heat exchanger rises during cooling operation, the outdoor air temperature and the outdoor heat exchanger temperature are greatly different. However, by operating the outdoor fan after the compressor is stopped, the outdoor air temperature and the outdoor heat exchanger temperature are Approximate. However, the value fluctuates up and down with respect to the actual outside air temperature in the middle stage. Therefore, a value closer to the actual outside air temperature is obtained by performing correction by adding a predetermined correction value (ΔT2) to the outdoor heat exchanger temperature at the end of the outdoor fan operation, that is, the estimated outside air temperature Tout.

  FIG. 4 shows the change rate ΔTout / Δt of the outdoor heat exchanger temperature during outdoor fan operation (tb) when the compressor is stopped, and the difference ΔTout between the actual outside air temperature and the estimated outside air temperature (outdoor heat exchanger temperature). It is. Since the temperature difference increases as the rate of change increases, by performing a correction that adds a predetermined correction value (ΔT3) to the outdoor heat exchanger temperature, that is, the estimated outside air temperature Tout at the start of compressor operation, the actual outside air temperature is further increased. Get a close value.

  FIG. 5 is a control time chart when the compressor is stopped with a mode change. In A, since the compressor is stopped immediately after switching from cooling to heating, the outside temperature is not updated when the compressor is restarted. In B, since the compressor is stopped during the heating operation, the outside temperature is updated when the compressor is restarted. Do.

  FIG. 6 is a control time chart when the compressor is continuously stopped. In A, since it is less than the predetermined time (td) since the previous compressor stop, the outside air temperature is not updated when the compressor is restarted, and in B, the predetermined time (td) since the previous compressor stopped. As described above, the outside air temperature is updated when the compressor is restarted.

  As described above, in the present embodiment, by adding a predetermined correction value to the estimated outside air temperature according to the operation mode and the immediately preceding estimated outside air temperature value, erroneous detection of the outside air temperature can be avoided and detection accuracy can be improved. This makes it possible to provide comfortable air conditioning.

  In the present embodiment, when the temperature change rate of the outdoor heat exchanger temperature is large, by adding a predetermined correction value to the estimated outside air temperature, erroneous detection of the outside air temperature is avoided, and detection accuracy is improved. This makes it possible to provide comfortable air conditioning.

  Further, in the present embodiment, when continuous operation is performed with a change in the operation mode, the compressor stop due to the change in the operation mode is not regarded as the compressor stop, and the estimated outside air temperature is not updated, so that the compressor is The number of forced stops is reduced, and comfortable air conditioning can be provided without false detection.

  In the present embodiment, when the compressor stops within a certain period (td) after the compressor is operated, the compressor is forcibly stopped by not updating the estimated outside air temperature without considering the compressor stopped. The number of times is reduced, and comfortable air conditioning can be provided without false detection.

  As described above, the air conditioner according to the present invention can estimate the outside air temperature without using the outside air temperature sensor, so that it is used for estimating the outside temperature of a heating device such as a fan heater or a device such as a dehumidifier. It can also be applied to.

Flowchart of outdoor temperature prediction control of the air conditioner in Embodiment 1 of the present invention The conceptual diagram of the time-dependent change of the outdoor heat exchanger temperature at the time of heating operation in Embodiment 1 of this invention Conceptual diagram of change with time of outdoor heat exchanger temperature during cooling operation in Embodiment 1 of the present invention Correlation diagram between the rate of change in outdoor heat exchanger temperature and the difference between outdoor air temperature and outdoor heat exchanger temperature in Embodiment 1 of the present invention Time chart of outside temperature estimation control in each operation mode and compressor ON / OFF according to Embodiment 1 of the present invention Time chart of outside temperature estimation update permission and compressor ON / OFF according to Embodiment 1 of the present invention Correlation diagram between temperature of outdoor heat exchanger of conventional air conditioner and elapsed time from shutdown

Claims (5)

An outdoor heat exchanger temperature detecting means for detecting the temperature of the compressor, the outdoor heat exchanger, the outdoor fan, and the outdoor heat exchanger is provided, and the outdoor fan is operated for a predetermined time and obtained from the outdoor heat exchanger temperature detecting means. Among the air conditioners characterized in that the outside air temperature during the compressor operation is estimated from the temperature of the outdoor heat exchanger obtained, the immediately preceding estimated outside air temperature in the heating operation is recognized as being equal to or higher than a predetermined temperature (Tc). A predetermined correction value (ΔT1) is added to the estimated outside air temperature. 2. The air conditioner according to claim 1, wherein a predetermined correction value (ΔT <b> 2) is added to the estimated outside air temperature when the immediately preceding estimated outside air temperature is recognized to be equal to or lower than a predetermined temperature (Td) in the cooling operation. 3. The air according to claim 1, wherein a correction value (ΔT3) is added to the estimated outside air temperature when the temperature change rate of the outdoor heat exchanger temperature during outdoor fan operation is large after the compressor is stopped. Harmony machine. 4. When performing a continuous operation accompanied by a change in the operation mode, the compressor stop due to the operation mode change is not regarded as a compressor stop, and the estimated outside air temperature is not updated. The air conditioner described in Crab. The compressor according to any one of claims 1 to 4, wherein when the compressor is stopped within a certain period (td) after the compressor is operated, the compressor is not regarded as being stopped and the estimated outside air temperature is not updated. Air conditioner.

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