JP2006145083A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner having superior heating performance and capable of minimizing degradation of amenity caused by deicing. <P>SOLUTION: In this separate type air conditioner separated into the inside and outside, and comprising an outside air temperature detecting means 68 for detecting an outside air temperature and an outdoor heat exchanger temperature detecting means 67 for detecting an outdoor heat exchanger temperature, a first conditional expression [Y=a×(X)+b] and a second conditional expression [Y=a×(X)+c] calculated from the outside air temperature X and the outdoor heat exchanger temperature Y are prepared (a is positive constant and b>c), and deicing is started when a prescribed deicing starting condition is satisfied when the outdoor heat exchanger temperature exists in a lower area of the first conditional expression, or the deicing is started when the outdoor heat exchanger temperature exists in a lower area of the second conditional expression, thereby deicing control is properly performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner that performs deice control in heating operation.

Conventionally, during a heating operation with a separate type air conditioner, the indoor heat exchanger is at a high temperature and the outdoor heat exchanger is at a low temperature. Therefore, when the outside air temperature is low to some extent (2 degrees to 5 degrees or less), the temperature of the outdoor heat exchanger is 0 degrees or less, and when moisture is present to some extent, it forms frost and adheres to the outdoor heat exchanger. If the heating operation continues thereafter, the frost gradually grows, and eventually the heat exchange capability in the outdoor heat exchanger is hindered, and the heating capability is gradually reduced. In order to prevent this, when it can be estimated that frost has grown to some extent, an electronic controller of the air conditioner is used for determination, and an operation for melting the frost (hereinafter referred to as a deice operation) is performed. Unlike normal heating operation, this operation switches the four-way valve for cooling operation, sends hot gas to the outdoor heat exchanger, and melts frost adhered to the outdoor. In this case, in order to maintain a high temperature outside the room and to prevent the user from feeling a cold wind, it is common to operate with both fans stopped. That is, it is basically operated with zero heating capacity. For this reason, deice operation is one of the complaints of air conditioners for users, and it is an important issue to perform deice operation efficiently. In other words, it is important to control the amount of frost adhering to the outdoor heat exchanger at the beginning of the defrosting operation under all outdoor temperature conditions where frosting occurs, and the conventional technology for solving this problem As shown in Patent Document 1, a defrosting instruction is given according to a primary expression Y = a · X−b (a and b are positive constants) calculated from the outside air temperature X and the outdoor heat exchanger temperature Y. Then, de-ice control aiming at a constant amount of frost formation was performed. This is shown in FIG. The horizontal axis represents the outside air temperature, and the vertical axis represents the outdoor heat exchanger temperature. When entering the region B, de-ice is performed.
JP-A-55-137439

  However, in the above-described conventional technique, only the primary expression of the outside air temperature and the outdoor heat exchanger temperature is used as a parameter to determine whether or not to perform de-ice, and other parameters that affect frost formation. The effects of certain frequencies, room temperature, indoor fan speed, outdoor fan speed, outside humidity, etc. are not taken into account, and in some cases, de-ice operation may be performed in a situation where there is almost no frost formation. There was a problem of deteriorating the heating capacity. On the other hand, there is a problem that the control condition is not satisfied even in a state where frosting has progressed, and the progress of the result cannot be suppressed. Further, even when the outdoor temperature is high, if the outdoor heat exchanger temperature is in the region B of FIG. 7, de-ice is performed, so there is a problem of performing meaningless de-ice in a situation where no frost is formed. In addition, since the outside air temperature is used as a parameter, if the outside air temperature sensor cannot obtain an appropriate outside air temperature for some reason, especially if an outside air temperature lower than the actual temperature is obtained, frost formation Despite the large amount, there was a problem that no de-ice was performed.

  The present invention solves the above-described conventional problems, and an object thereof is to provide an air conditioner that is superior in heating performance and prevents deterioration of comfort due to deice as much as possible by appropriately performing deice control during heating operation. To do.

In order to solve the above-described conventional problems, the air conditioner of the present invention is a separate type air conditioner separated into the inside and outside, and detects the outside air temperature detecting means for detecting the outside air temperature, and the outdoor heat exchanger temperature. In the air conditioner provided with the outdoor heat exchanger temperature detecting means, a first conditional expression and a second conditional expression, which are calculated from the outdoor air temperature and the outdoor heat exchanger temperature, are provided. When the outdoor heat exchanger temperature is in the lower region of the conditional expression, the deice is started if the predetermined deice start condition is satisfied, or the outdoor heat exchanger temperature is in the lower region of the second conditional expression If it is, start the de-ice.

  As a result, in the lower region of the first conditional expression, another reference is added as to whether or not frosting is occurring. In addition, in the lower region of the second conditional expression, deice is performed unconditionally.

  Moreover, the air conditioner of this invention does not perform de-ice if the outdoor heat exchanger temperature exceeds a predetermined value. Accordingly, the outside air temperature is ignored, and de-ice is not performed if the outdoor heat exchanger temperature is equal to or higher than a predetermined temperature.

  Furthermore, the air conditioner of the present invention performs de-ice when the outdoor heat exchanger temperature is equal to or lower than a predetermined temperature. As a result, the outside air temperature is ignored, and the de-ice control is performed when the outdoor heat exchanger temperature falls below a predetermined temperature.

  The air conditioner of the present invention can provide an air conditioner that is excellent in heating performance and prevents deterioration of comfort due to deice as much as possible by appropriately performing deice control during heating operation.

1st invention is the air conditioner of the separate type separated into the inside and outside, and is equipped with the outside air temperature detection means which detects outside temperature, and the air conditioner provided with the outdoor heat exchanger temperature detection means which detects outdoor heat exchanger temperature The first conditional expression (Y = a · X + b) and the second conditional expression (YY = a · X + c) calculated from the outdoor air temperature X and the outdoor heat exchanger temperature Y are provided (where a is a positive value) A constant and b> c), when the outdoor heat exchanger temperature is in the lower region of the first conditional expression, the de-ice is started if a predetermined de-ice start condition is satisfied, or the outdoor heat exchanger When the temperature is in the lower region of the second conditional expression, by starting the de-ice, in the lower region of the first conditional expression, it is possible to add another criterion for whether or not frosting is performed, By increasing the accuracy of deice control That. In addition, the de-icing is performed unconditionally in the lower area of the second conditional expression, so that in the lower area of the first conditional expression, the criterion for determining whether or not frosting is provided is set inappropriately. Even when it is not possible to determine that frost formation has occurred due to the influence of the outside environment or the like, it is possible to prevent the state in which frost formation has progressed from being continued, and it is possible to appropriately perform deice control.

  In particular, in the air conditioner according to the first aspect of the present invention, the change rate of the heat exchanger temperature is greater than or equal to a predetermined change rate when the heat exchanger temperature falls as the predetermined deice start condition. In this case, it is possible to determine whether or not the outdoor heat exchanger is clogged by starting the de-ice, so that a more appropriate frosting state can be grasped and the de-ice control can be appropriately performed.

  In a third aspect of the present invention, in particular, in the air conditioner of the first or second aspect, when the predetermined deice start condition, a predetermined time elapses after the outdoor heat exchanger temperature falls below the first condition value Even if the outdoor humidity is low and the outdoor heat exchanger cannot be determined by the rate of change in the heat exchanger temperature by starting the de-ice, the frosting is progressing to some extent. In a lower region of a certain first conditional expression, the deice control is performed after a predetermined time has elapsed, so that the state in which frost formation has progressed can be prevented, and the deice control can be performed as appropriate.

  According to a fourth aspect of the invention, in particular, in the air conditioner of any one of the first to third aspects of the invention, if the outdoor heat exchanger temperature exceeds a predetermined value, de-ice is not performed, so that the outside air temperature is high. In the state where there is no frost formation, since deice is not performed, inappropriate deice can be prevented.

  In the fifth aspect of the invention, in particular, in the air conditioner of any one of the first to fourth aspects, when the outdoor heat exchanger temperature is equal to or lower than a predetermined temperature, de-ice is performed. Even if it is covered with frost or snow due to frost or snow, and the outside temperature cannot be obtained properly, the outside air temperature is ignored, and if the outdoor heat exchanger temperature falls below the predetermined temperature, de-ice is performed. It is possible to prevent the state where frost formation has progressed from being continued, and it is possible to appropriately perform deice control.

  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. 6 is an example of a configuration diagram of the air conditioner according to the present embodiment. In the figure, 61 is connected to an outdoor heat exchanger, a compressor 62, an expansion valve 63, an indoor heat exchanger 65, and a four-way valve 66 in one system. And heat exchange is performed with the wind emitted by 64 outdoor fans. When the heating operation is performed for a long time, the temperature of 61 outdoor heat exchangers gradually decreases, and frost is generated and grows depending on conditions. As the frost grows gradually, the ventilation resistance increases, the amount of heat exchange decreases, and the heating capacity decreases. In the air conditioner, the defrosting operation is performed by estimating / determining the state where frost has been grown to some extent in the outdoor heat exchanger temperature sensor 67 and the output of the outdoor air temperature sensor 68 by the electronic control unit 69.

  About the air conditioner comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  FIG. 1 is a conceptual diagram of the deice determination in the embodiment of the present invention. In FIG. 1, a region A is a region where no de-ice is performed, a region B is a region where de-ice is performed depending on conditions, and a region C is a region where de-ice is performed unconditionally. Here, a description will be given of how to define the first conditional expression and the second conditional expression. As a result of experiments, a drop in capacity from the maximum value of the heating capacity at each outdoor temperature (for example, 90% of the maximum capacity), the outdoor heat exchanger temperature and the outdoor temperature in the situation (90% of the maximum capacity) are approximately linear. (See FIG. 3). Therefore, if this relationship is utilized, it becomes possible to put in the deice when the heating capacity falls from the maximum value to a certain level. However, it is known that the linear relationship between the outdoor heat exchanger temperature and the outdoor air temperature fluctuates due to the influence of frequency, indoor air temperature, indoor fan speed, outdoor fan speed, and outdoor humidity. If you just use, you can't always put it on the ice cream at the right time. Therefore, as a mitigation measure, allowance is given to the outdoor heat exchanger temperature and the outside air temperature above and below the target maximum capacity, and specifically, the outdoor heat at the target maximum capacity drop. The first conditional expression was converted to a first-order equation from the approximately linear relationship between the exchanger temperature and the outside air temperature. Two conditional expressions were used. In this way, another deice determination condition can be provided in the region B, and the accuracy of deice control can be increased.

In addition, as for the method of determining the drop from the target maximum capacity, when adding deice when there is almost no drop from the maximum capacity, the deice operation is frequently performed in a situation where the amount of frost formation is small, and the deice for the heating operation time Since the proportion of operation time increases and the heating time becomes shorter, the cumulative heating capacity decreases, and energy is required to raise the temperature of the outdoor heat exchanger every deice operation, and thus wasteful energy is consumed. It will be. On the other hand, when the drop from the maximum capacity is large, although the heating operation time per cycle becomes long, the heating capacity is reduced due to frost formation, not only wasteful energy is consumed, but also the amount of frost formation is large. Diice driving time will be longer and comfort will be lost. Therefore, it is necessary to determine the fall from the target maximum capacity in consideration of balance. In the embodiment of the present invention, it is considered that the ice cream is put in about 90% of the maximum capacity, which almost coincides with the point where the outdoor heat exchanger is clogged. Of course, the effects of frequency, room temperature, indoor fan speed, outdoor fan speed, and the like may be included in the primary expression. Further, this time, the linear relationship between the outdoor heat exchanger temperature and the outside air temperature is replaced as a linear expression, but it may be replaced with a quadratic expression or another polynomial.

  In FIG. 1, deice is not performed when Ta is equal to or higher than this value. However, since the deairing is not performed in a state where the outside air temperature is high and frost is not formed, inappropriate deice can be prevented. In addition, if it is Tb or less, de-icing is performed, but even if the outside temperature sensor is covered with frost or snow due to frost or snowfall and the outside temperature cannot be acquired properly, the outside temperature is ignored. However, when the outdoor heat exchanger temperature becomes equal to or lower than the predetermined temperature, deice is performed, so that the state in which frost formation has progressed can be prevented, and deice control can be appropriately performed.

  FIG. 2 is a flowchart in the embodiment of the present invention.

  First, when the heating operation is performed in FIG. 2, it is determined whether or not the vehicle is in the region A (see FIG. 1) in SP21. If so, the heating operation is continued, and if not, the process proceeds to SP22. In SP22, it is determined whether or not the user is in the area B (see FIG. 1). If so, the process proceeds to SP23. If not, the process is in the area C (see FIG. 1), and deice is performed. In SP23, it is determined whether or not the absolute value of the change rate of the outdoor heat exchanger temperature is equal to or greater than a predetermined value and the change rate is negative (| ΔT |> ΔTa and ΔT <0). Otherwise, go to SP24. Here, the grounds for determining the deice depending on the condition of SP23 will be described. The experiment gave results as shown in FIG. FIG. 4 is a plot of heating capacity and outdoor heat exchanger temperature on the vertical axis, and operating time on the horizontal axis, and it can be seen that the heating capacity and outdoor heat exchanger temperature drop sharply from a certain point. At this point, the outdoor heat exchanger is beginning to clog, and by using this sudden drop in the outdoor heat exchanger temperature, de-ice can be performed with high accuracy. However, with regard to the sudden drop in the outdoor heat exchanger temperature, when this condition is used in the region A, when the outdoor heat exchanger temperature suddenly falls due to some disturbance, there is no frost formation or almost no frost formation. Even in a situation where frost is not formed, the ice cream enters the ice cream. Therefore, it is not preferable to use only the rate of change in the outdoor heat exchanger temperature as a condition for determining the ice ice temperature. If you are in B) you need to put in Diaz. In SP24, it is determined whether or not a predetermined time has elapsed (for example, 20 minutes) after entering the region B. If so, de-ice is performed, and if not, the process returns to SP22. FIG. 5 shows changes over time in the heating capacity and the outdoor heat exchanger temperature when the outside humidity is low (for example, 70% or less). As can be seen from FIG. 5, a rapid decrease in the outdoor heat exchanger temperature cannot be observed under low humidity conditions, and the rate of change in the outdoor heat exchanger temperature cannot be used as the de-ice determination condition. However, even under low humidity, the region B is frosted to some extent, and it is not preferable that this state continues for a long time, leading to a decrease in the cumulative heating capacity. Therefore, when a certain amount of time (for example, 20 minutes) has elapsed (this time may be determined so that the cumulative heating capacity is maximized) after entering the region B, the ice cream is put into the deice.

As described above, in the present embodiment, when the outdoor heat exchanger temperature is in the region B in FIG. 1, the de-ice is started if the predetermined de-ice start condition is satisfied, or the outdoor heat exchanger temperature is In the area C in FIG. 1, by starting the de-ice, it is possible to add another reference for whether or not frost is formed in the area B, and to improve the accuracy of the de-ice control. In addition, in the area C, the de-ice is unconditionally performed. However, in the area B and below, the frost is formed due to an improper setting of whether or not other frost formation is provided or the influence of the external environment or the like. Even when it is not possible to determine that the frosting has occurred, it is possible to prevent the frosting state from continuing, and the deice control can be appropriately performed.

  Further, in the present embodiment, as the predetermined deice start condition, when the rate of change of the heat exchanger temperature becomes equal to or greater than the predetermined rate of change when the temperature of the heat exchanger decreases, deice is started. Thus, it can be determined whether or not the outdoor heat exchanger is clogged, so that a more appropriate frost formation state can be grasped and de-ice control can be performed as appropriate.

  Further, in the present embodiment, as the predetermined deice start condition, when a predetermined time has elapsed after the outdoor heat exchanger temperature falls below the region B, the dehumidification is started so that the outdoor humidity is low and the outdoor heat exchange is started. Even if it is not possible to determine whether the heat exchanger is clogged by the rate of change of the heat exchanger temperature, the de-ice control is performed after a certain time has passed in the region B where frosting has progressed to some extent. Further, it is possible to prevent the state in which frost formation has progressed from being continued, and it is possible to appropriately perform deice control.

  In addition, in this embodiment, if the outdoor heat exchanger temperature exceeds a predetermined value, the de-ice is not performed, so that the de-ice is not performed in a state where the outside air temperature is high and no frost is formed. Can prevent a serious dying.

  In addition, in this embodiment, when the outdoor heat exchanger temperature is equal to or lower than a predetermined temperature, de-ice is performed, so that the outdoor temperature sensor is covered with frost or snow due to frost or snowfall, and appropriately Even when the outside air temperature can no longer be acquired, the outside air temperature is ignored, and when the outdoor heat exchanger temperature falls below the predetermined temperature, de-ice is performed, so that it is possible to prevent the frosting state from continuing. Therefore, the deice control can be performed as appropriate.

  As described above, the air conditioner according to the present invention appropriately performs deice control at the time of heating operation, so that it is excellent in heating performance and can prevent deterioration of comfort due to deice as much as possible. Applicable to harmony machines.

Conceptual diagram of diice determination in Embodiment 1 of the present invention Flowchart in Embodiment 1 of the present invention The relationship figure which showed the relationship between the outdoor heat exchanger temperature and the outdoor temperature at the time of 90% of maximum capacity | capacitance about the heating capability in each outdoor temperature in Embodiment 1 of this invention The relationship figure which showed the relationship between the heating capability in Embodiment 1 of this invention, outdoor piping temperature, and operation time. The relationship figure which showed the relationship between the heating capability at the time of the low humidity in Embodiment 1 of this invention, outdoor piping temperature, and operation time The block diagram of the air conditioner which concerns on Embodiment 1 of this invention. Conceptual diagram of deice determination in a conventional air conditioner

Explanation of symbols

61 Outdoor Heat Exchanger 62 Compressor 63 Expansion Valve 64 Outdoor Blower 65 Indoor Heat Exchanger 66 Four-way Valve 67 Outdoor Heat Exchange Temperature Sensor 68 Outdoor Air Temperature Sensor 69 Electronic Control Unit

Claims (5)

In an air conditioner that is a separate type air conditioner that is separated into the inside and outside, and that includes an outside air temperature detecting means that detects the outside air temperature, and an outdoor heat exchanger temperature detecting means that detects the outside heat exchanger temperature, the outside air temperature X And the first conditional expression (Y = a · X + b) calculated from the outdoor heat exchanger temperature Y and the second conditional expression (Y = a · X + c) are provided (where a is a positive constant and b> c), when there is an outdoor heat exchanger temperature in the lower region of the first conditional expression, de-ice is started if a predetermined de-ice start condition is satisfied, or the outdoor heat exchanger temperature is An air conditioner that starts de-ice when it is in the lower region of the conditional expression. 2. The deice start is started when the rate of change of the outdoor heat exchanger temperature is equal to or greater than a predetermined rate of change when the temperature of the outdoor heat exchanger decreases, as the predetermined deice start condition. Air conditioner as described in. The deicing is started when the outdoor heat exchanger temperature enters the lower region of the first conditional expression and the predetermined time has passed as the predetermined deice start condition. The air conditioner described. The air conditioner according to any one of claims 1 to 3, wherein de-ice is not performed if the outdoor heat exchanger temperature exceeds a predetermined value. The air conditioner according to any one of claims 1 to 4, wherein de-ice is performed when the outdoor heat exchanger temperature falls below a predetermined value.

Images