KR20120012955A

KR20120012955A - Air conditioning apparatus

Info

Publication number: KR20120012955A
Application number: KR1020110076895A
Authority: KR
Inventors: 노리따까 나까야
Original assignee: 아이신세이끼가부시끼가이샤
Priority date: 2010-08-03
Filing date: 2011-08-02
Publication date: 2012-02-13
Also published as: JP5499982B2; KR101568894B1; EP2428754A2; JP2012037066A; EP2428754B1; EP2428754A3

Abstract

The air conditioning apparatus 1 includes a refrigeration cycle and an idle defrosting operation determining apparatus 20, wherein the refrigeration cycle comprises a compressor 11, an indoor heat exchanger 16, a pressure reducer constituting a fluid circuit through which a cooling medium circulates. (17) and an outdoor heat exchanger (15), the outdoor heat exchanger (15) acts as an evaporator when performing a heating operation and as a condenser when performing a defrosting operation, and determines an idle defrosting operation. The device 20 includes a temperature detection device 21 for detecting a pipe temperature T of an outdoor heat exchanger; Low temperature integral value calculating means 20 for calculating a low temperature integral value A; High temperature integral value calculating means 20 for calculating a high temperature integral value B; And determining means 20 for determining whether to perform an idle defrosting operation based on the magnitude relationship between the low temperature integration value A and the calculated high temperature integration value B. FIG.

Description

Air Conditioning Equipment {AIR CONDITIONING APPARATUS}

The present invention generally relates to an idle defrosting operation determining apparatus for an air conditioning apparatus that determines whether to perform an idle defrosting operation which is considered as an unnecessary defrosting operation during the heating operation of the air conditioning apparatus.

In general, in cold weather conditions (eg, winter), frost can occur in the outdoor heat exchanger while the air conditioning unit is performing a heating operation, thereby reducing the heating performance of the air conditioning unit during operation. Therefore, an air conditioner such as a heat pump or the like generally performs reverse cycle operation (corresponding to a cooling operation) while the air conditioner is in operation, thereby defrosting the outdoor heat exchanger (to melt frost formed in the outdoor heat exchanger). Configured to execute. However, even if the frost is not actually formed in the outdoor heat exchanger, if the defrosting operation is continued for longer than necessary time, the temperature of the room cannot be adjusted during the defrosting operation, which may cause inconvenience to the user. Can cause unnecessary energy consumption. Therefore, a number of methods (ie, idle defrosting operation) have been proposed to avoid the performance of the defrosting operation while no frost is formed in the outdoor heat exchanger.

For example, in JP2004-232942A, the defrosting operation of the outdoor heat exchanger is performed by changing the temperature of the indoor heat exchanger obtained every time at a predetermined time, the temperature difference between the temperature of the indoor heat exchanger and the room temperature, and the mask time (from the start of the heating operation). A defrosting control method for an air conditioner is disclosed that is configured to perform a defrosting operation of an outdoor heat exchanger for a predetermined period of time based on a predetermined elapsed time of a mask time. If the defrosting operation is continuously carried out over a plurality of times of mask time while the temperature drop of the indoor heat exchanger is below a predetermined value, the defrosting control method disclosed in JP2004-232942A is carried out between the temperature of the indoor heat exchanger and the room temperature. By setting the temperature difference to a value lower than the initial setting value, the defrosting operation is performed by switching the operating condition to the operating condition at the low ambient temperature, thereby preventing the idle defrosting operation during the heating operation under the low ambient temperature condition. To be.

In JP2002-130876A, during the defrosting operation, if the defrosting operation is terminated based on the temperature of the cooling pipe of the outdoor heat exchanger, the defrosting operation time ( That is, a controller for an air conditioner configured to set a time as a freezing point approximation time) is disclosed. Then, the air conditioner controller disclosed in JP2002-130876A prevents the defrosting operation, which prevents subsequent (next) defrosting operation depending on the length of the duration of the defrosting operation when it is confirmed that the temperature of the cooling pipe is approximately at the freezing point. You are changing the time. Thus, the defrosting operation can be performed in response to, for example, an ambient environment (eg, outdoor weather conditions).

Thus, in short, there are two general forms of methods for preventing idle defrosting operations (ie, methods for determining idle defrosting operations). One is a method based on temperature detection in a room as disclosed in JP2004-232942A. The other is a method based on the detection of the cooling pipe temperature in the outdoor unit.

According to the controller for an air conditioner disclosed in JP2002-130876A, the controller actually makes an idle defrosting operation determination when the temperature of the cooling pipe of the outdoor heat exchanger exceeds a freezing point and reaches a predetermined heating reset temperature, and then the controller Disables defrosting. If a relatively low temperature (eg 2 ° C.) is used as the heating reset temperature, the defrosting operation can be stopped even if the frost remains on the outdoor heat exchanger. Thus, the idle defrosting operation decision in that case may not have been made sufficiently accurate. On the other hand, if a relatively high temperature (e.g., 10 DEG C) is set as the heating reset temperature, the frost is actually on the outdoor heat exchanger since it takes time for the cooling piping temperature to reach the heating reset temperature after the start of the defrosting operation. Even if it is not left, the defrosting operation can last longer than necessary.

In addition, as a method for determining idle defrosting operation in an outdoor unit such as the method disclosed in JP2002-130876A, many known defrosting methods exist. For example, there is a method for determining idle defrosting operation that is performed by estimating whether frost is formed in an outdoor heat exchanger based on a temperature rise tendency (derivative value) of a pipe temperature of an outdoor heat exchanger. There is also a method of determining idle defrosting operation that is performed by time-setting the duration after which the pipe temperature of the outdoor heat exchanger rises from the freezing point after the defrosting operation is performed. However, the detection accuracy of the above method may vary depending on the setting of the piping temperature used for the determination. In addition, the methods described above may require a relatively long time from when the piping temperature reaches a predetermined set temperature to the end of the idle defrosting operation determination.

Accordingly, there is a need to provide an idle defrosting operation determining apparatus for an air conditioning apparatus that is configured to quickly and accurately perform a determination of whether to perform an idle defrosting operation.

According to one aspect of the invention, an air conditioning apparatus includes a refrigeration cycle and an idle defrosting operation determining apparatus, wherein the refrigeration cycle comprises a compressor, an indoor heat exchanger, a pressure reducer connected to form a fluid circuit through which a cooling medium passes and circulates. And an outdoor heat exchanger, wherein the outdoor heat exchanger operates as an evaporator for evaporating the cooling medium when performing heating operation, and as a condenser for condensing the cooling medium when performing defrosting operation, Is a temperature detecting device for detecting a pipe temperature of the outdoor heat exchanger, and the freezing point temperature and the pipe temperature when the pipe temperature detected during the defrosting operation is a temperature range between a predetermined low temperature lower than the freezing point temperature and the freezing point temperature. Through integration or summation based on time of temperature difference between A low temperature integral value calculating means for calculating a low temperature integral value, and a temperature difference between the freezing point temperature and the pipe temperature if the pipe temperature detected during the defrosting operation is a temperature range between a predetermined high temperature higher than the freezing point temperature and the freezing point temperature. Means for calculating the high temperature integral value through the integral or summation based on the time of and whether or not to perform the idle defrosting operation based on the magnitude relationship between the calculated low temperature integral value and the calculated high temperature integral value. Determining means for determining.

Thus, the determination of whether to perform the idle defrosting operation can be performed quickly without degrading the determination accuracy.

According to another aspect of the invention, the freezing point temperature refers to the freezing point of water.

According to another aspect of the invention, the freezing point temperature of the water varies with atmospheric pressure.

According to another aspect of the present invention, the temperature detection device processes the piping temperature of the outdoor heat exchanger as an integer value.

According to another aspect of the present invention, the temperature detection device is outdoors by decreasing the value below the decimal point when the pipe temperature indicates a positive value, and increasing the value below the decimal point when the pipe temperature indicates a negative value. The piping temperature of the heat exchanger is obtained as an integer value.

According to another aspect of the invention, the temperature detection device measures the pipe temperature of the outdoor heat exchanger each time at a predetermined time.

According to the present invention, the determination of whether to perform the idle defrosting operation in the air conditioning apparatus can be performed quickly and accurately.

Further features and characteristics as well as the above-described features and characteristics of the present invention will become more apparent upon consideration of the following detailed description with reference to the accompanying drawings.
1 is a circuit diagram of an air conditioning apparatus according to an embodiment.
2 is a graph showing the pipe temperature change of the outdoor heat exchanger while the defrosting operation is being performed.
3A and 3B are more detailed and enlarged graphs showing the pipe temperature change of the outdoor heat exchanger while the defrosting operation is being performed.
4 is a table comparing idle defrosting operation determination method and known idle defrosting operation determination method according to an embodiment of the present invention.
5 is a flowchart illustrating a control process executed by the idle defrosting operation determining method according to an embodiment of the present invention.

An embodiment of an idle defrosting operation determining apparatus for an air conditioning apparatus will be described with reference to the accompanying drawings. 1 shows a circuit diagram of a heat pump type air conditioner 1 (hereinafter, simply referred to as air conditioner 1). The air conditioning apparatus 1 constitutes a refrigeration cycle. As shown in FIG. 1, the air conditioner 1 includes a compressor 11, a four-way valve 14, an outdoor heat exchanger 15, an indoor heat exchanger 16, and an electromagnetic expansion valve 17 (that is, a pressure reducer). ) And cooling pipe (18). More specifically, the compressor 11, the indoor heat exchanger 16, the electromagnetic expansion valve 17 and the outdoor heat exchanger 15 are connected to form a fluid circuit through which the cooling medium circulates to form a refrigeration cycle. Cooling piping 18 is used to circulate the cooling medium to the compressor 11 or the like. The air conditioning apparatus 1 also includes a control apparatus 20 configured to control the operation of the compressor 11, the four-way valve 14, the electromagnetic expansion valve 17, and the like. The control device 20 consists of a microprocessor as a core and functions as an idle defrosting operation determining device. In addition, the control device 20 is electrically connected to a temperature sensor 21 provided on the surface of the cooling pipe 18 located adjacent to the outlet 15a of the outdoor heat exchanger 15 and serving as a temperature detection device. More specifically, the temperature sensor 21 is provided in a part of the cooling pipe 18 used as a pipe extending between the outlet 15a of the outdoor heat exchanger 15 and the electromagnetic expansion valve 17 in the outdoor device. . The temperature sensor 21 is configured to detect the piping temperature T (ie surface temperature) of the cooling medium discharged from the outdoor heat exchanger 15 while the defrosting operation is being performed. The resolution of the pipe temperature T detected by the temperature sensor 21 is set to 1 degree (1 ° C.) (However, numerical values below the decimal point are generally ignored, and more specifically, values below the decimal point for positive values). Is ignored and rounded up for negative values). The control device 20 obtains the pipe temperature T every second. For example, when the actual temperature is −0.9 degrees (−0.9 ° C.), the temperature sensor 21 detects the temperature as zero (0 ° C.). When the actual temperature is -3.5 degrees (-3.5 degrees Celsius), the temperature sensor 21 detects the temperature as -3 degrees (-3 degrees Celsius). On the other hand, when the actual temperature is 0.9 degrees (0.9 degrees Celsius), the temperature sensor 21 detects the temperature as zero degree (0 degrees Celsius). In addition, when the actual temperature is 1.6 degrees (1.6 ° C), the temperature sensor 21 detects the temperature as 1 degree (1 ° C).

The air conditioning operation performed by the air conditioning apparatus 1 will be described below with reference to FIG. 1. The flow of the cooling medium when the cooling operation is performed is shown by the solid arrow. On the other hand, the flow of the cooling medium in the case where the heating operation is performed is shown by the broken arrow. In the cooling operation, the cooling medium discharged from the compressor 11 passes through the four-way valve 14 and then goes to the outdoor heat exchanger 15 which functions as a condenser. The heat of the cooling medium is removed by air (ambient air) in the outdoor heat exchanger 15 to condense the cooling medium. The cooling medium is then depressurized in the electromagnetic expansion valve 17 and evaporated to remove heat of the air in the room in the indoor heat exchanger 16 which functions as the evaporator. Thereafter, the cooling medium is returned to the compressor 11 through the four-way valve 14. Thus, the room is cooled through the above process.

On the other hand, in the heating operation, the cooling medium discharged from the compressor 11 passes through the four-way valve 14 and is condensed and liquefied in the indoor heat exchanger 16 which functions as a condenser to release heat into the air in the room. . Thereafter, the cooling medium is depressurized in the electromagnetic expansion valve 17 and evaporated in the outdoor heat exchanger 15 which functions as an evaporator to absorb the heat of the air that is outdoors. Thereafter, the cooling medium is returned to the compressor 11 through the four-way valve 14. Therefore, the room is warmed through the above-described process.

If the control device 20 detects that the predetermined defrosting start-up conditions are detected during the execution of the heating operation, the defrosting operation (ie reverse cycle operation) for circulating the cooling medium is started as in the case of the cooling operation. . The formation of frost on the outdoor heat exchanger 15 such as, for example, the duration of the heating operation (ie, the time elapsed since the previous defrosting operation), the piping temperature T of the outdoor heat exchanger 15 and the ambient air temperature. This anticipated appropriate condition may be adopted as the defrosting operation start condition.

While the defrosting operation is performed, the cycle is reversed so that the outdoor heat exchanger 15 functions as a condenser. Therefore, in the defrosting operation, a hot cooling medium is sent to the outdoor heat exchanger 15 so that the pipe temperature T in the outdoor heat exchanger 15 is increased. Thus, in this case the piping temperature T detected by the temperature sensor 21 corresponds to the piping temperature on the downstream side of the outdoor heat exchanger 15 in the flow of the cooling medium during the execution of the defrosting operation. For example, when the piping temperature T at the time when the defrosting operation is started is -10 degrees (10 ° C), the piping temperature T gradually increases after the defrosting operation is started. Then, when the pipe temperature T rises and reaches the freezing point TO, approximately when the frost is formed in the outdoor heat exchanger 15, the frost melts and is removed. When the control device 20 detects the fulfillment of the predetermined defrosting operation satisfying condition in the continuous defrosting operation, the defrosting operation is terminated. For example, the defrosting in the outdoor heat exchanger 15 such as the duration of the defrosting operation (ie, the time elapsed since the previous heating operation), the piping temperature T of the outdoor heat exchanger 15, the ambient air temperature, and the like. This presumed appropriate condition can be adopted as the defrosting termination condition. In this embodiment, the freezing point refers to the freezing point of water and changes with atmospheric pressure.

Hereinafter, with reference to FIG. 2, the test result of the piping temperature of the outdoor heat exchanger 15 in the case where frost is formed in the outdoor heat exchanger 15 and when frost is not formed in the outdoor heat exchanger 15 is demonstrated. . As shown by the solid line in FIG. 2, when the frost is actually formed on the outdoor heat exchanger 15 at the start of the defrosting operation, the tendency of temperature rise of the pipe temperature T is approximately equal to the pipe temperature T. After rising to the freezing point temperature T0 (i.e. 0 ° C), it slows down (i.e. becomes smaller), because the pipe temperature T of the outdoor heat exchanger 15 is included in a temperature range lower than the freezing point temperature T0. This is because the pipe temperature T increases with a predetermined tendency. Thereafter, when the piping temperature T reaches approximately the freezing point temperature T0, a portion of the frost or ice formed on the surface of the outdoor heat exchanger 15 starts to melt (i.e., the portion of the frost or ice is dipped). Melting starts from the upstream side of the coolant during the roasting operation), and then the frost or ice formed on the surface of the outdoor heat exchanger 15 is converted to saturation, so that the hot cooling medium flows through the cooling pipe 18. The heat of (ie, heat capacity) is used as heat of fusion instead of being used to increase the piping temperature (T). After the frost or ice formed on the surface of the outdoor heat exchanger 15 is almost melted and the piping temperature T of the outdoor heat exchanger 15 exceeds the freezing point temperature T0, the piping temperature T is determined in a predetermined tendency. It starts to rise again, and the tendency of temperature rise becomes relatively rapid (it becomes remarkable).

As shown by broken lines in FIG. 2, when no frost is formed on the outdoor heat exchanger 15 at the time when the defrosting operation is executed, the piping temperature T is a low temperature range and a high temperature across the freezing point temperature T0. It continues to rise with a predetermined trend within the range.

The tendency of the temperature rise of the piping temperature T of the outdoor heat exchanger 15 while the defrosting operation is being performed is considered to follow the above phenomenon. However, if the frost is actually formed on the outdoor heat exchanger 15, the timing of the change in the temperature rise tendency of the pipe temperature T up to approximately the freezing point temperature T0 is such that the defrosting operation (i.e. reverse cycle operation) is started. It was found to fluctuate depending on the piping temperature T at the time point or the circulation of the cooling medium and other factors. Therefore, when determining whether to perform the idle defrosting operation, the control device 20 (i.e., the low temperature integral value calculating means and the high temperature integral value calculating means is substantially aware of the change in the temperature rise tendency of the pipe temperature T). Time of temperature difference between freezing point temperature T0 and piping temperature T in the low temperature range (eg -2 ° C to 0 ° C) and the high temperature range (eg 0 ° C to 2 ° C) across the freezing point temperature T0 The integral value for is calculated as the low temperature integral value A and the high temperature integral value B. Then, the controller 20 compares the low temperature integral value A with the high temperature integral value B, thereby controlling the controller. 20. That is, the determining means can determine whether to perform the idle defrosting operation while absorbing (removing) the above-described fluctuations, which are in the form of frost-forming states where the tendency of temperature rise is slowed (smaller). (I.e. idle defrosting If not performed), the low temperature integral value A increases and becomes larger than the high temperature integration value B, and is removed by comparing the low temperature integration value A and the high temperature integration value B. On the other hand, no frost is formed. In the case of a state (i.e., when an idle defrosting operation is performed), the low temperature integration value A and the high temperature integration value B tend to have the same value.

More specifically, the low temperature range in which the piping temperature T used for the calculation of the low temperature integral value A is placed (that is, the temperature range in which the temperature rise tends to decrease (smaller) during the frost formation state) is determined by the predetermined low temperature ( T1 (negative magnitude) to a freezing point temperature T0. The time when the piping temperature T reaches the low temperature T1 from the low temperature range lower than the low temperature T1 is set to t1. The time when the pipe temperature T reaches the freezing point temperature T0 (that is, the time when the freezing point temperature T0 is first detected) is set to t01. In addition, the high temperature range in which the piping temperature T used for the calculation of the high temperature integrated value B is placed is set in a range from the freezing point temperature T0 to a predetermined high temperature T2 (positive magnitude). The time at which the pipe temperature T starts to rise from the freezing point temperature T0 (that is, the time when the freezing point temperature T0 was last detected) is set to t02. Further, the final time (that is, the time when the high temperature T2 was last detected) at which the pipe temperature T reaches the high temperature T2 is set to t2. In this case, the low temperature integration value A and the high temperature integration value B are respectively calculated by the following equations.

Here, Δt represents a timing cycle (one second in this embodiment) of the control device 20 for recording the time of the pipe temperature T.

The idle defrosting operation is based on the relationship between the value obtained by multiplying the predetermined adjustment factor k (0 <k <1) by the hot integral value B (= kB) and the cold integral value A (i.e., the magnitude relationship). It is determined whether or not to execute based on this. More specifically, when the low temperature integral value A is greater than the value kB (that is, A> kB), the tendency of temperature rise of the piping temperature T is slowed down in the low temperature range across the freezing point temperature T0. It is considered to be (smaller). Thus, in this case the control device 20 determines not to perform the idle defrosting operation. On the other hand, if the low temperature integration value A is less than or equal to the value kB (i.e., A ≤ kB), it is considered that the temperature rise tends not to slow down (small) within the low temperature range across the freezing point temperature T0, The control device 20 determines to carry out the idle defrosting operation. In addition, the adjustment factor is used to prevent a false determination that the control device 20 decides not to perform the idle defrosting operation even if the frost is formed on the outdoor heat exchanger 15.

Thus, the freezing point A and the high temperature integral B are used to emphasize the tendency of the temperature rise of the outdoor heat exchanger 15 in each of the low and high temperature ranges across the freezing point temperature T0. Even if the temperature to be reached from the temperature T0 (e.g., the high temperature T2) is low, that is, the idle defrosting operation is executed even if the elapsed time since the piping temperature T exceeds the freezing point temperature T0 is short. Whether or not to be determined may be appropriately determined. As a result, the time required by the control device 20 to determine whether to execute the idle defrosting operation can be shortened without degrading the reliability of the idle defrosting operation determining apparatus for the air conditioning apparatus 1.

If the control device 20 determines not to execute the idle defrosting operation, the control device 20 continues the defrosting operation until the fulfillment of the predetermined defrosting operation termination condition is detected. On the other hand, when the control device 20 determines to execute the idle defrosting operation, the control device 20 immediately stops the defrosting operation and executes the predetermined defrosting operation end control to start the heating operation again. . Thus, system control can be achieved that improves user comfort and energy savings.

Hereinafter, referring to FIG. 3, as an example of the determination of whether to execute the idle defrosting operation while the defrosting operation is performed, the low temperature T1 is set to -2 degrees (-2 ° C) and the high temperature T2 is It demonstrates under the conditions set to 2 degree | times (2 degreeC). 3A and 3B show graphs showing a change in the piping temperature T of the outdoor heat exchanger 15 while the defrosting operation is being performed. In this example, the value "0.8" is used as the adjustment coefficient. As mentioned above, the temperature sensor 21 is comprised so that resolution may be set to 1 degree | time (1 degreeC). In addition, the control device 20 obtains the pipe temperature T every second. In other words, the circulation cycle is 1 second.

The case where the tendency of temperature rise becomes slow (smaller) in the low temperature range across the freezing point temperature TO is described below. As shown in Fig. 3A, in response to the defrosting operation, the piping temperature T reaches -2 degrees (-2 deg. C) and the piping after the control device 20 starts to calculate the low temperature integral value A. The temperature T is maintained at -2 degrees (-2 degrees Celsius) for 5 seconds and -1 degrees (-1 degrees Celsius) for 7 seconds. : It is assumed that the low temperature integrated value A is calculated as follows.

A = (0-(-2)) * 5+ (0-(-1)) * 7 = 17

In addition, in response to the defrosting operation, after the pipe temperature T starts to rise from the freezing point temperature T0 and the control device 20 starts to calculate the high temperature integral value B, the pipe temperature T is set to 1 second. Assuming that it is maintained at 1 degree (1 ° C.) for 2 seconds and 2 degrees (2 ° C.) for 2 seconds, the high temperature integral value B can be calculated as follows.

B = (1-0) * 1 + (2-0) * 2 = 5

Therefore, the relationship "A = 17 is larger than kB = 4 (that is, A = 17> kB = 4)" is established. Therefore, control device 20 determines not to perform the idle defrosting operation in the manner described above (ie, the frosted state).

Hereinafter, the case where the temperature rise tends not to slow down (small) in the low temperature range across the freezing point temperature TO is described. As shown in FIG. 3B, the piping temperature T reaches -2 degrees (-2 ° C.) in response to the defrosting operation and the piping after the control device 20 starts to calculate the low temperature integral value A. The pipe temperature (T) is freezing point temperature (T0; 0 degrees) by maintaining the temperature (T) at -2 degrees (-2 degrees Celsius) for 1 second and -1 degrees (-1 degrees Celsius) for 1 second. : It is assumed that the low temperature integrated value A is calculated as follows.

A = (0-(-2)) * 1+ (0-(-1)) * 1 = 3

Further, after the pipe temperature T starts to rise from the freezing point temperature T0 and the control device 20 starts to calculate the high temperature integral value B, the pipe temperature T is 1 degree (1 ° C. for 1 second). Assuming that it is maintained at < RTI ID = 0.0 >) and < / RTI >

B = (1-0) * 1 + (2-0) * 2 = 5

Therefore, the relationship "A = 3 is kB = 4 or less (that is, A = 3 <kB = 4)" is established. Therefore, control device 20 determines to perform the idle defrosting operation in the manner described above (ie, no frost is formed).

In Fig. 4, the relationship between the reliability when the determination of the idle defrosting operation is completed and the pipe temperature T (ie, T2) of the outdoor heat exchanger 15 according to the idle defrosting operation determining apparatus of the present invention, and the known idle According to the defrosting operation determination device, a table of data obtained experimentally is shown to compare the relationship between the reliability when the determination of the idle defrosting operation is completed and the piping temperature of the outdoor heat exchanger. In the experimental test, the idle defrosting operation determining device estimates the frost formation on the outdoor heat exchanger 15 based on the temperature rise tendency (derivative value) of the pipe temperature T of the outdoor heat exchanger. An idle defrosting operation determining apparatus configured to determine whether or not to execute is adopted as a known idle defrosting operating determining apparatus.

As shown in Fig. 4, according to the known idle defrosting operation determining apparatus, the pipe temperature T of the outdoor heat exchanger 15 used to complete the determination of whether to perform the idle defrosting operation is 10 degrees ( 10 ° C.), it is precisely determined whether or not the idle defrosting operation is performed. However, according to the known idle defrosting operation determining apparatus, when the pipe temperature T of the outdoor heat exchanger 15 is set to 2 degrees (2 ° C.), whether to perform the idle defrosting operation is not accurately determined. While the pipe temperature T is low, the temperature rise tends to be unstable, which is likely to cause false crystals. Therefore, in order to obtain an accurate determination result, it is necessary to use the high piping temperature T by which the temperature rise tendency becomes stable.

On the other hand, according to the idle defrosting operation determining apparatus of the present invention, the pipe temperature (T) of the outdoor heat exchanger 15 used to complete the determination of whether to perform the idle defrosting operation is 10 degrees (10 ° C) and 2 Accurate crystals were obtained in all cases set at degrees (2 ° C). The above results indicate that the determination made by the control device 20 compares the low temperature integration value A across the freezing point temperature T0 with the high temperature integration value B, thereby reducing the circulation medium, the ambient temperature, and the like. It is considered to be obtained because it can be received. Therefore, the idle defrosting operation determining apparatus of this embodiment can quickly and accurately determine whether to perform the idle defrosting operation.

The determination process of the control device 20 for determining whether to execute the idle defrosting operation will be described below with reference to the flowchart shown in FIG. This process is called when the piping temperature T reaches the low temperature T1 after the defrosting operation is started in accordance with the detection of the fulfillment of the defrosting operation starting condition.

When the process shown in FIG. 5 is started, the control device 20 determines the low temperature integral value A and the high temperature integral value B in the manner described above as the pipe temperature T rises with the defrosting operation. (S1). Subsequently, the control device 20 determines whether or not the low temperature integral value A is equal to or less than the value kB obtained by multiplying the high temperature integration value B by the adjustment coefficient k (S2). When the control device 20 determines that the low temperature integration value A is equal to or less than the value kB (YES in S2), the control device 20 determines to perform an idle defrosting operation (S3). On the other hand, when the control device 20 determines that the low temperature integration value A is greater than the value kB, the control device 20 determines not to perform the idle defrosting operation (S4). Thereafter, the process ends. In addition, the defrosting operation ends when the control device 20 determines to execute the idle defrosting operation. On the other hand, when the control device 20 determines not to execute the idle defrosting operation, the control device 20 continues the defrosting operation until the satisfaction of the defrosting operation termination condition is detected.

According to this embodiment, the following advantages and advantages are obtained. According to this embodiment, each of the low temperature integration value A and the high temperature integration value B used to determine whether to perform the idle defrosting operation is in the low temperature range (low temperature T1) across the freezing point temperature T0. Temperature difference with respect to the integrated freezing point temperature T0 with respect to time in each of the range from freezing point temperature T0] and the high temperature range (range from freezing point temperature T0 to high temperature T2). Thus, for example, the fluctuations in the temperature rise tendency of the outdoor heat exchanger 15 can be absorbed (removed) due to the influence of the cooling medium circulation, so that the execution of the idle defrosting operation can be determined within a narrower temperature range [ That is, the high temperature T2 is lower than the set temperature in the known idle defrosting operation determining apparatus. As a result, whether or not to execute the idle defrosting operation can be determined quickly and accurately.

According to this embodiment, it is not necessary to provide a humidity sensor or the like in the idle defrosting operation determining apparatus to determine whether to perform the idle defrosting operation. Thus, the number of parts used in the idle defrosting operation determining apparatus can be reduced. In addition, the idle defrosting operation determining apparatus according to the present embodiment may be modified as follows.

In this embodiment, the low temperature T1 is set to −2 degrees (2 ° C.) and the high temperature T2 is set to 2 degrees (2 ° C.) as an example. For example, it is not necessary to make the low temperature T1 and the high temperature T2 the same level (that is, the same absolute value). Further, the adjustment factor k can be changed depending on the desired precision (reliability) of determining whether or not to perform the idle defrosting operation for the set low temperature T1 and the high temperature T2. More specifically, to avoid erroneously determining that the control device 20 performs the idle defrosting operation, the lower the desired precision of the determination of whether or not to execute the idle defrosting operation, the smaller the adjustment factor k becomes a smaller value. Can be set.

The calculation cycle Δt (1 second) of the control device 20 for obtaining the piping temperature T is just one example.

1: air conditioning system 11: compressor
14: four-way valve 15: indoor heat exchanger
16: outdoor heat exchanger 17: electronic expansion valve
18: cooling piping 20: control device
21: temperature sensor

Claims

Air conditioning equipment,
A refrigeration cycle and idle defrosting operation determining device,
The refrigeration cycle comprises a compressor, an indoor heat exchanger, a pressure reducer, and an outdoor heat exchanger connected to form a fluid circuit through which the cooling medium passes, wherein the outdoor heat exchanger evaporates to evaporate the cooling medium when the heating operation is performed. As a condenser to condense the cooling medium,
The apparatus for determining idle defrosting operation includes a temperature detecting device for detecting a pipe temperature of the outdoor heat exchanger, and a temperature between a predetermined low temperature and a freezing point temperature at which a pipe temperature detected during the defrosting operation is lower than a freezing point temperature. Range, the low temperature integral value calculating means for calculating a low temperature integral value through integration or summation based on the time of the temperature difference between the freezing point temperature and the pipe temperature, and the pipe temperature detected during the defrosting operation is the freezing point temperature. A high temperature integral value calculating means for calculating a high temperature integral value through integration or summation based on the time of the temperature difference between the freezing point temperature and the pipe temperature when the temperature range is between a higher predetermined high temperature and the freezing point temperature, and the calculated low temperature. Magnitude relationship between integral value and the calculated high temperature integral value , The air conditioner on the basis of a determining means for determining whether to perform the idle operation deep roasting.

The air conditioning apparatus of claim 1, wherein the freezing point temperature is a freezing point of water.

The air conditioning apparatus according to claim 2, wherein the freezing point temperature of the water varies with atmospheric pressure.

The air conditioning apparatus according to claim 1, wherein the temperature detection device processes the piping temperature of the outdoor heat exchanger as an integer value.

The outdoor heat exchange method of claim 4, wherein the temperature detection device rounds down a value below the decimal point when the pipe temperature indicates a positive value, and raises the value below the decimal point when the pipe temperature indicates a negative value. The air conditioning apparatus which acquires the piping temperature of a machine as an integer value.

The air conditioning apparatus according to claim 4, wherein the temperature detection device measures a pipe temperature of the outdoor heat exchanger each time at a predetermined time.