JP5525965B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus having a refrigerant amount determination function.

  The refrigerant amount determination function is broadly classified into one that is mainly determined using hardware and one that is determined by software using only operation state data without using a special sensor. Although the method of determining using hardware is highly accurate, it requires a cost for a tank, a measuring device, and the like, and in recent years, a method using software is often used.

  As a refrigerant quantity determination device using software, there is one disclosed in Patent Document 1. In Patent Document 1, the degree of supercooling at the outlet of the heat source side heat exchanger or the amount of operating state that fluctuates according to the fluctuation of the degree of subcooling is detected, and the suitability of the refrigerant amount is determined by comparing with the target supercooling degree value. ing.

JP 2006-23072 A

  However, since the thing of the said patent document 1 compares the supercooling degree measured at a certain time with the supercooling degree corresponding to the refrigerant | coolant amount required for a driving | operation, from normal operation mode to refrigerant | coolant amount determination mode etc. Switching to a special operating state, the refrigeration cycle must be stable when measuring the degree of supercooling. Therefore, there is a problem that it is difficult to determine the refrigerant amount during normal operation where the refrigeration cycle is likely to be unstable.

  An object of the present invention is to accurately determine the amount of refrigerant during normal operation.

In order to achieve the above object, the present invention provides a refrigeration cycle apparatus in which a compressor, an outdoor heat exchanger, and a supercooling heat exchanger are connected by piping, and a pipe between the outdoor heat exchanger and the supercooling heat exchanger. And an outdoor bypass expansion valve provided in a bypass pipe connected to a suction side pipe of the compressor, and a supercooling heat exchange for measuring a supercooling heat exchanger outlet supercooling degree at an outlet of the supercooling heat exchanger Based on the amount of operation of the outdoor bypass expansion valve, the amount of operation of the outdoor bypass expansion valve, the degree of supercooling of the outlet of the supercooling heat exchanger obtained based on the amount of operation of the outdoor bypass expansion valve, and the amount of operation of the outdoor bypass expansion valve A control arithmetic unit that identifies an estimated value of the supercooling heat exchanger outlet subcooling degree during normal operation from the theoretical supercooling heat exchanger outlet subcooling degree obtained by Out of the supercooling heat exchanger And judging the refrigerant quantity by using the estimated value of the degree of subcooling.
The present invention also relates to an refrigeration cycle apparatus in which a compressor, an outdoor heat exchanger, and an outdoor expansion valve are connected to each other, and an outdoor heat exchanger outlet for measuring the degree of subcooling of the outdoor heat exchanger outlet at the outlet of the outdoor heat exchanger. A temperature detector, the amount of operation of the outdoor expansion valve, the degree of subcooling of the outdoor heat exchanger outlet obtained based on the amount of operation of the outdoor expansion valve, and the outdoor heat obtained based on the amount of operation of the outdoor expansion valve Identifying the estimated value of the subcooling degree of the outdoor heat exchanger outlet during normal operation from the theoretical degree of subcooling of the outdoor heat exchanger outlet obtained based on the degree of supercooling degree of the exchanger outlet and the operation amount of the outdoor expansion valve A control arithmetic unit that determines the amount of refrigerant using an estimated value of the degree of subcooling at the outlet of the outdoor heat exchanger.

  According to the present invention, the amount of refrigerant can be accurately determined during normal operation.

It is a flowchart of refrigerant | coolant amount determination in Example 1 of this invention. It is a refrigeration cycle system diagram in Example 1 of the present invention. It is a graph showing a mode that the dynamic characteristic coefficient of the supercooling heat exchanger exit supercooling degree with respect to the outdoor bypass expansion valve opening degree changes with respect to the time step when the refrigerant leaks. It is a graph showing the change of the supercooling heat exchanger exit supercooling degree with respect to the amount of encapsulated refrigerant when the ratio of the refrigerant flow rate flowing through the outdoor bypass expansion valve is constant. It is the graph which represented the supercooling heat exchanger exit | side supercooling degree for every enclosure refrigerant | coolant amount with respect to the ratio with respect to the total refrigerant | coolant flow rate which flows through an outdoor bypass expansion valve. It is a flowchart of refrigerant | coolant amount determination in Example 1 of this invention. The horizontal axis represents the test signal, the vertical axis represents the probability density function, and is a graph representing the normal determination region and the abnormality determination region, and the magnitude of the first type error probability and the second type error probability. It is a flowchart of refrigerant | coolant amount determination using the test | inspection in Example 1 of this invention. It is a flowchart of refrigerant | coolant amount determination in Example 2 of this invention. It is a refrigeration cycle system diagram in Examples 3 and 4 of the present invention.

  Embodiments of the present invention will be described below.

  FIG. 1 is a flowchart of refrigerant amount determination in the present embodiment. FIG. 2 is a block diagram showing the configuration of the air conditioner and the refrigerant amount determination device, which has one or a plurality of outdoor units, one or a plurality of indoor units, and the outdoor unit and the indoor unit. A closed circuit is formed by pipe connection, and the refrigerant is enclosed in the closed circuit.

  The outdoor units 211 and 21N include one or a plurality of compressors 221 and 22N, outdoor heat exchangers 231 and 23N, and outdoor heat exchangers 231 and 23N, which are variable or fixed in operating speed (hereinafter referred to as frequency). The outdoor expansion valves 281 and 28N for adjusting the flow rate are piped, and the outdoor fans 241 and 24N for blowing air to the outdoor heat exchangers 231 and 23N are provided.

  The indoor units 411 and 41M sequentially pipe indoor heat exchangers 421 and 42M that exchange heat with indoor air and indoor expansion valves 441 and 44M that adjust the refrigerant flow rate of the indoor heat exchanger, and also the indoor heat exchanger 421. , 42M are provided with indoor fans 431, 43M.

  The outdoor units 211 and 21N have accumulators 251 and 25N and four-way valves 261 and 26N, and can be used without the liquid receivers 271 and 27N. Further, the gas side and the liquid side of the outdoor units 211, 21N and the indoor units 411, 41M are connected to the gas side pipes 321, 32N, 36, 401, 40M, the liquid side pipes 311, 31N, 35, 391, 39M and The branch pipes 33, 34, 37, and 38 are connected to form a closed circuit, and the refrigerant is enclosed in the closed circuit. Moreover, the indoor units 411 and 41M are respectively arranged in the utilization units 611 and 61M that are air conditioning targets.

  Further, the outdoor unit includes outdoor temperature detectors 551 and 55N that detect outdoor temperature, compressor refrigerant discharge temperature detectors 531 and 53N, compressor suction pressure detectors 561 and 56N that detect compressor refrigerant suction pressure, and compression. Compressor discharge pressure detectors 571 and 57N for detecting the refrigerant discharge pressure of the compressor, inverter compressor frequency controllers 451 and 45N for operating the frequency of the compressor, and an outdoor fan air blowing capacity operator 461 for operating the air blowing capacity of the outdoor fan. 46N, outdoor expansion valve opening operation devices 471 and 47N for operating the outdoor expansion valve opening, and outdoor bypass expansion valve opening operation devices 481 and 48N for operating the outdoor bypass expansion valve opening, respectively.

  Furthermore, the utilization unit on the indoor side includes indoor unit suction temperature detectors 581 and 58M for detecting the utilization unit room temperature, indoor unit discharge temperature detectors 591 and 59M for detecting the temperature of air blown to the utilization unit, Indoor fan blowing capacity controllers 501 and 50M for operating the fan blowing capacity, indoor expansion valve opening level controllers 511 and 51M for controlling the indoor expansion valve opening, and storing preset values or the user's preference It has utilization part temperature setting devices 601 and 60M for setting the thermal environment.

  Further, a control calculation device 62 that performs normal control and other calculations, refrigerant amount determination, an information storage device 63, a use source display device 64, an information input device 65, a serviceman or an operation monitor, a product supplier to a designer A display device 66 and communication means 67 are connected.

  The above refrigerant quantity determination device may be attached to the air conditioner or may be removable. Next, operation | movement of the air conditioner by a present Example is demonstrated.

<Filling refrigerant during trial operation>
First, it is assumed that the air conditioner is filled with an appropriate amount of refrigerant during installation and trial operation. At the time of the initial test run, the contractor or serviceman takes time for that purpose, and thus a conventional refrigerant amount determination method may be used. Here, the appropriate amount of refrigerant means that when the air conditioner is operated to form a refrigeration cycle, for example, in the case of cooling operation, the outdoor heat exchanger outlet subcooling degree, the subcooling heat exchanger outlet subcooling degree, etc. The amount used for the determination of refrigerant leakage is an amount that falls within a preset range. In actual work, it is sealed in advance based on the construction pipe length. In the construction work, the construction pipe length may not be accurately grasped, and the volume of the indoor heat exchanger varies depending on the type of indoor unit.

<Normal control>
Next, general normal control of the air conditioner will be described. In the cooling operation, particularly when a plurality of outdoor units are connected, in order to make the refrigerant dryness uniform among the outdoor units, the dryness is 1.0 or the superheat degree is 0 or more in the outdoor unit gas side branch 34. Something is desirable. If the refrigerant dryness is less than 1.0, the refrigerant dryness distributed to each outdoor unit may differ, so one outdoor unit has a very high compressor discharge temperature, and the other outdoor unit This is because an undesirable state occurs as a refrigeration cycle in which the discharge temperature of the compressor becomes very low. Therefore, it is often designed to control the opening degree of the indoor expansion valves 441 and 44M so that the degree of superheat is secured at the outlets of the indoor heat exchangers 421 and 42N which are evaporators.

  If the degree of superheat of the indoor heat exchanger outlet is secured, this time, the refrigerant suction temperature becomes higher at the compressor suction portion, and the compressor discharge temperature becomes higher. Depending on the type of compressor, if the discharge temperature of the compressor becomes too high, the motor coil in the compressor will deteriorate, leading to poor insulation and deterioration of the internal refrigerator oil. There is a need to. Therefore, for example, as shown in FIG. 2, bypass pipes 292 and 292N are connected from the pipe between the outdoor expansion valve and the supercooling heat exchanger to the pipe on the compressor suction side, and the amount of refrigerant flowing through the bypass pipe is adjusted. An outdoor bypass expansion valve is provided in the bypass pipe, and a refrigerant having a low dryness is injected into the compressor suction portion to suppress the compressor suction dryness and the compressor discharge temperature. In this embodiment, one end of the bypass pipe is connected to the pipe between the accumulator and the four-way valve. These state quantities such as compressor discharge temperature and superheat degree are generally controlled to set values by PID control, model predictive control, or the like.

  There are also models equipped with supercooling heat exchangers 301 and 30N in order to supply a stable liquid refrigerant to the indoor unit side. The refrigerant flowing to the indoor unit exchanges heat with the low-temperature refrigerant that has passed through the outdoor bypass expansion valve and the supercooling heat exchanger, and is supplied to the indoor unit with supercooling. The degree of supercooling is detected by subcooling heat exchanger outlet temperature detectors 541 and 54N.

  In heating operation, the refrigerant returning to each outdoor unit is often in a liquid single phase, so that distribution at the outdoor unit side liquid side branching portion 33 is relatively easy, and consideration of the cooling time is unnecessary. There are many. Even when the refrigerant returns in two phases, the compressor discharge temperature of each outdoor unit can be controlled by individually controlling the outdoor expansion valves 281 and 28N. Alternatively, as in the case of cooling, the outlet superheat degree of the outdoor heat exchangers 231 and 23N as evaporators may be set to a set value, and the compressor discharge temperature may be controlled by the outdoor bypass expansion valve.

  In order to maintain stability and capacity as a refrigeration cycle, during cooling operation, the high pressure Pd is controlled to the set value by the outdoor fan operation amount, and the low pressure Ps or the evaporator temperature Te is set by the compressor frequency. It is often controlled by. During heating operation, the high pressure Pd is often controlled by the compressor frequency, and the low pressure Ps or the evaporator temperature is often controlled by the outdoor fan operation amount.

<Refrigerant amount determination>
This time, not only the stable state of the refrigeration cycle, but also the state quantity of the refrigerant at a certain point in time and the state quantity after operating the manipulated variable in the state quantity are measured during normal operation. The refrigerant quantity is determined based on whether or not the change corresponding to the manipulated variable is reflected in the state quantity. Thereby, even if the refrigeration cycle is not so stable as compared with the prior art, it can be determined.

  An operation start instruction is issued from the operation start unit 1, an activation instruction is issued from the air conditioner activation unit 2, and normal operation such as cooling and heating is performed according to the instruction of the normal control unit 3. The control computation device 62 may include execution of computation by the online system identification processing unit 5. In the identification process, the coefficient parameter determination unit 6 determines whether or not the identified value is within a normal range that can be used for the determination. If the value is out of the range, the data initialization unit 7 initializes the data to be normal. If it is within the range, the refrigerant amount is determined. For example, when it is determined that the refrigerant leakage condition is satisfied, the refrigerant amount decrease recognition unit 22 recognizes that fact and displays it on the use source display device 64 (display unit 1) by the display command unit 17. The communication processing unit 18 transmits refrigerant leakage information to a serviceman or the like, and the display command unit 19 displays the information on the product supplier display device 66 (display unit 2). When these information transmission and display are finished, the alarm stop processing unit 20 may stop the alarm if an alarm is issued.

  A case where the compressor discharge temperature is controlled by the outdoor bypass expansion valves 291 and 29N and the supercooling heat exchangers 301 and 30N are mounted will be described as an example.

The supercooling heat exchanger outlet supercooling degree and S _C, the operation amount of the command by the outdoor bypass expansion valve opening operating unit 481 (outdoor bypass expansion valve operation amount) expressed as e _B. These change from time to time during normal operation such as cooling or heating operation that air-conditions the room, and are expressed by the ARX model as one of the dynamic characteristic expression methods as follows.

Here, a _{1 to} a _n , b _{1 to} b _m , and n and m are constants. This is because the value of S _C (k) at the time k step is the value from S _C (k−n) n steps before it to the previous S _C (k−1) and the operation m steps before. This model is affected by the quantity e _B (k−m) to the immediately preceding e _B (k−1). The processing device 62 to identify the coefficients a ₁ ~a _n, the b ₁ ~b _m during operation, monitors the value constantly. This identification method includes a method of collecting data to some extent and performing it at once, or a method of performing it online every moment. However, since the storage capacity is small, an online system identification method is described. Estimate the coefficient obtained by the above identification
Hereinafter, these will be referred to as an estimated value a and an estimated value b, respectively. In addition, the estimation vector and the observation vector are defined as follows.

  Here, (·) ′ represents transposition, and the initial value of the estimated vector is known or 0. This estimated vector is the value shown in the formula below.

If it is designed to minimize the value, it can be obtained in the form of sequential calculation shown in the following formula.

Here, the meaning of minimizing the above equation (4) is to find parameters so that the obtained data most closely matches the above equation (1). An operation amount _{e B (k-1) ~e} B (k-m), changes in the state before quantity _{S C (k-1) ~S} C (k-n), after the change based on these state quantities S _C by obtaining a (k), during cooling and heating operation of the air conditioner, it is possible to identify an estimate a and b of the unknown parameters _{a 1 ~a n, b 1 ~b} m. In the above explanation, one input and one output system, no dead time, online system identification is a simple example of sequential least squares, but there are multiple input multiple output systems, dead time, other identification methods, and multiple outdoor units. It can be applied in the same way even when connected to a stand. For example, if the compressor discharge superheat is actually affected not only by the outdoor bypass expansion valve but also by the compressor frequency, the ARX model is used.

And it is sufficient. Where F _C is the compressor frequency value. Regardless of the model, there are cases where online system identification is unsuccessful and results in an impossible value, such as when the observation noise mixed in the detector is large. In that case, erase the data once and repeat the identification.

The meaning of the above formula (1) represents the dynamic characteristics with time as a parameter, and the current state quantity (supercooling heat exchanger outlet supercooling degree) depends on the past state quantity and the past manipulated variable. It is. It also represents the sensitivity of the state quantity with respect to the manipulated variable when the refrigeration cycle has reached a stable equilibrium after a sufficient amount of time. Therefore, if the actual state quantity obtained based on a certain operation amount is different from the state quantity that should be obtained (theoretical state quantity), how much the state quantity is in spite of performing the same operation Change will be different. Incidentally, the coefficient _{a 1 ~a n, b 1 ~b} m is the true value as the observed value can not be detected, it is determined by the estimated values a and b.

Here is a simple example. In this system, the expression (1) is most simplified, and the coefficients a and b are only a ₁ and b ₁ . In addition, when a certain amount of operation is applied, the state quantity does not diverge infinitely or hunting is performed. If e _B (k−1) = e _B = constant value and time has passed sufficiently (theoretical infinite time), S _C (k) = S _C (k−1) = S _C at infinite time. For,
Thus, it can be said that the sensitivity S _C / e _B of the state quantity S _C with respect to the manipulated variable e _B is expressed by the coefficients a ₁ and b _{1 in} this way. This concept, model number of complex unknown parameters are the same even when _{a 1 ~a n, b 1 ~b} m and more. In that case, a function for converting a large number of numerical values into one numerical value (a function for converting a vector into a scalar), which conforms to Equation (8), may be used.

  Specifically, when the amount of refrigerant changes, the estimated value b of the coefficient obtained by identification changes. How the amount of change (difference) between the actual state quantity and the state quantity that should be obtained fluctuates is determined by observing a change in the estimated value b that has a correlation with the state quantity based on the manipulated variable. . That is, it can be said that it is the sensitivity of the state quantity, so that the change in the refrigerant quantity can be estimated by observing the estimated value b.

For example, sealed refrigerant becomes small amount of refrigerant leaking, despite open the outdoor bypass expansion valve, not allowed to flow sufficient amount of refrigerant to the subcooling heat exchanger, S _C is not taken sufficiently (The value decreases). In that case, the values of the estimated value a and the estimated value b themselves change, and when the refrigerant leaks, the estimated value b decreases. In the extreme, if the estimated value b is 0, even if how to operate the outdoor bypass expansion valve, the supercooling heat exchanger outlet supercooling degree S _C, a state that can not be influence at all. FIG. 3 shows an example of the estimated value b in which the correlation value gradually decreases due to refrigerant leakage and becomes equal to or less than a predetermined value. This predetermined value is determined from the true value 69 with a normal range 70 as a certain degree of likelihood. When the estimated value b is equal to or less than a predetermined value, it is determined that the refrigerant is leaking. Of course, the likelihood may be zero. 4 shows a case of fixing refrigerant flow rate and the total refrigerant flow rate flow rate ratio of passing through the outdoor bypass expansion valve (outdoor bypass expansion valve flow rate) constant at 0.20, the change in the S _C for enclosed refrigerant amount . However, FIG. 4 shows the static characteristics, which are characteristics when stabilized for a sufficient time. As shown in FIG. 4, the value of S _C is reduced since refrigerant heat exchange decreases the amount of refrigerant is small in the subcooling heat exchanger. From this, the value of S _C at the same degree of opening the refrigerant leaks is reduced, also reduced the estimated value b that is identified, it can be determined refrigerant leakage by observing the change in the estimated value b. Accordingly, if a predetermined value can be set in advance whether the normal operation can be performed with respect to the estimated value b in the appropriate refrigerant amount for each condition such as the pipe length and the indoor / outdoor temperature, that is, in a normal case If the value of the sensitivity is known, a value corresponding to the value is set as a threshold value, and when the value is equal to or less than the threshold value, it can be determined that the refrigerant leaks.

In recent years, especially HFCs and other refrigerants are taking a strict stance such as regulations on refrigerant leakage, such as European F gas regulations, because of their high global warming potential. In addition, even if a refrigerant with a low global warming potential such as CO ₂ or other low GWP refrigerants is used, it may cause cooling or heating failure due to the leakage of the refrigerant. Judgment is an important function.

  In recent large-scale air conditioners, there is a construction example in which 100 kg or more of refrigerant is sealed in one refrigeration cycle, and as much as 10 kg of refrigerant is released into the atmosphere with 10% refrigerant leakage. However, since there are many products with a design likelihood of 10% or more with respect to the amount of refrigerant, the air conditioner continues to operate even when 10 kg leaks, while the cooling and heating capabilities are reduced. Further, when the refrigerant leaks from the outdoor unit, the brazed portion of the pipe connecting the outdoor unit and the indoor unit, or the flare nut fastening unit, the amount of refrigerant in the refrigeration cycle gradually decreases. A slight refrigerant leak is difficult to detect during a trial operation, and it is determined whether the refrigerant has leaked as a secular change when operated for a long time.

According to the present embodiment, the outdoor bypass expansion valve operation amount e _B (k-1) and ~e _B (k-m), the state amount before the change (subcooling heat exchanger outlet supercooling degree) S _C (k −1) to S _C (k−n), and the state quantity S _C (k) after the change based on these, the unknown parameters a _{1 to} a _n , b ₁ to b during air conditioning operation of the air conditioner b _m is identified, the estimated value a and the estimated value b are obtained, and the change in the estimated value b, which is the sensitivity of the state quantity (supercooling heat exchanger outlet supercooling degree) with respect to the manipulated variable, is used for the determination. Become. For this reason, the stable state of the refrigeration cycle at the time of determination is unnecessary as compared with the prior art, and it can be determined with high accuracy during normal operation. Further, frequent determination can prevent a large amount of leakage even when the refrigerant is leaking. Furthermore, since the refrigerant leakage can be detected promptly, the cooling and heating capacity does not decrease. Therefore, the user's discomfort does not increase and the power consumption does not increase in order to compensate for the decrease in performance.

Although only the determination of refrigerant leakage has been described above, there may be excessive refrigerant due to excessive addition of refrigerant at the beginning of air conditioning installation, etc., and how much the estimated value b has changed over time. By determining ΔB to be expressed as follows, such an increase in refrigerant can also be determined. If ΔB is negative, the refrigerant amount increases. If ΔB is close to 0, the refrigerant amount does not change. If ΔB is positive, it is determined that the refrigerant amount has decreased. Further, threshold values δ ₁ and δ ₂ are provided to clarify the judgment, and it is preferable to determine that the refrigerant amount has been increased or decreased when it has changed greatly beyond a predetermined value.
[Refrigerant amount increase]: The amount of change ΔB of the estimated value b is negative (ΔB ≦ −δ ₁ ).
[No change in refrigerant amount]: The change amount ΔB of the estimated value b is 0 (−δ ₁ <ΔB ≦ δ ₂ ).
[Refrigerant amount decrease]: The amount of change ΔB of the estimated value b is positive (ΔB> δ ₂ ) (δ ₁ and δ ₂ are positive).
In the present embodiment, the air conditioner has been described. However, the environment on the use side may be any one that exchanges heat with a gas such as air or a liquid such as water, and can be used for a refrigeration cycle such as a refrigerator. The same applies to the following embodiments.

5, the outdoor bypass expansion valve flow ratio at a certain construction of the refrigeration cycle is a diagram showing how S _C will look like. This figure also shows the static characteristics when the refrigeration cycle is stable. For example, in the range where the flow rate ratio is 0.15 or more, if the refrigerant is excessive, the negative gradient with respect to the outdoor bypass expansion valve flow rate ratio, and the moderate amount is a moderate positive value. gradient, the under-0, a 0 the value of S _C itself.

  When the amount of the enclosed refrigerant is excessive and the flow rate ratio is small, the refrigerant in the refrigeration cycle is mainly stored in the outdoor heat exchanger, and the degree of subcooling at the outlet of the outdoor heat exchanger and the degree of supercooling at the inlet of the subcooling heat exchanger are large. Therefore, the degree of supercooling at the outlet of the supercooling heat exchanger also increases. Therefore, the gradient becomes positive up to a certain outdoor bypass expansion valve flow ratio. However, as the flow rate ratio increases, the refrigerant is more likely to move and accumulate on the accumulator side, so it is less likely to be stored in the outdoor heat exchanger, and the degree of subcooling at the outdoor heat exchanger outlet and the degree of supercooling at the subcooling heat exchanger inlet are The supercooling degree at the outlet of the supercooling heat exchanger is also reduced. Therefore, the gradient becomes negative with respect to the outdoor bypass expansion valve flow rate ratio. This is not because heat transfer in the subcooling heat exchanger 301 is reduced.

FIG. 6 shows a flowchart for determining the amount of refrigerant using dynamic characteristics. “When the outdoor bypass expansion valve is operated in a certain region (here, the flow ratio is 0.15 or more), when the refrigerant is excessive, a negative gradient with respect to the outdoor bypass expansion valve flow ratio, positive when the refrigerant amount is appropriate, The characteristic that the coefficient is 0 when it is too small is used. That is, the determination is made based on the estimated value b itself. At this time, if the determination is made as follows, an appropriate refrigerant amount determination can also be performed. Note that the thresholds B ₁ and B ₂ are determined based on the actual customer's pipe length, height difference, outdoor unit, indoor unit variation, air temperature conditions, and the like. This refrigerant amount determination can also be used in the following examples.
[Excessive amount of refrigerant]: Estimated value b <−B ₁ <0
[Refrigerant amount appropriate]: Estimated value b> B ₂ ≧ 0
[Refrigerant quantity too small: estimate b is 0 and S _C itself 0 (B ₁ is positive, B ₂ is 0 or a positive)

<Certification process>
The refrigerant amount can also be determined in the above manner, but it can be more reliably determined by combining it with a test process for statistical processing. The test is “(1) Define a certain standard, (2) Inspect, and (3) Perform statistical processing when determining pass / fail, grade, etc.”. Dynamics factor (1) subcooling heat exchanger outlet supercooling degree as examples _{a 1 ~a n, b 1 ~b} m is (2) the system identification result, (3) whether it is normal or abnormal A test method for judging the above will be described.

  FIG. 7 is a graph showing the normality determination area 71 and the abnormality determination area 72, and the magnitude of the first type error and the second type error, with the horizontal axis representing the test signal and the vertical axis representing the probability density function. FIG. 8 is a flowchart of refrigerant quantity determination using the test in the present embodiment. In this embodiment, the verification process performed by the verification processing unit 86 in FIG. 8 will be described in detail. This verification process is performed by the control arithmetic unit 62.

  Since there are n and m coefficients, respectively, if each test is performed, processing when the results are different becomes difficult. Therefore, we will evaluate with one value by the weighted norm shown below.

Dynamic characteristic coefficients a ₁ ~a _n of the supercooling heat exchanger outlet supercooling degree, when asked to estimate a and the estimated value b of the b ₁ ~b _m, when originally they that minimizes the expression (4), Statistical processing has already been implemented in the sense of minimizing white observation noise. However, the dynamic characteristics of the subcooling heat exchanger outlet subcooling dynamic characteristics of complex refrigeration cycles are subject to observation noise such as errors due to reduction in dimensions, detector errors, and electrical noise that approximate eq. (1), and infinite samples It is considered that the value is probabilistic. Therefore, the following hypothesis is determined by avoiding handling the obtained coefficient as it is as 100% reliable.

Hypothesis H ₀ : The state indicated by the dynamic characteristic coefficient of the degree of supercooling at the outlet of the supercooling heat exchanger is
Normal (appropriate amount of refrigerant).

Hypothesis H ₁ : The state indicated by the dynamic characteristic coefficient of the degree of supercooling at the outlet of the supercooling heat exchanger is
Abnormal (excessive or insufficient refrigerant amount).

In FIG. 7, when the coefficient A enters the region R ₀ with the boundary line _AB as a boundary, the hypothesis H ₀ is received, and when the coefficient A enters the region R ₁ , the hypothesis H ₁ is received.

73 is a probability density function 73 with a normal condition that “the air conditioner is normal when the value of the supercooling heat exchanger outlet subcooling degree dynamic characteristic coefficient is detected as A ₀ ”, and p ( A | _A0 ). 74 is a probability density function 74 with an abnormal condition that “the air conditioner is abnormal when the value of the supercooling heat exchanger outlet supercooling degree dynamic characteristic coefficient is detected as A ₁ ”, p This is expressed as (A | A ₁ ).

Here, A ₀ and A ₁ are fixed and known values. Actually, when developing an air conditioner, data is previously obtained and a value is obtained.

According to the above definition, the area E ₀ is a probability that the hypothesis H ₁ is accepted and the result is abnormal even though the air conditioner is normal (appropriate refrigerant amount), The error probability is 76. The area E ₁ is the probability of accepting the hypothesis H ₀ and making a decision that the air conditioner is normal even though the air conditioner is abnormal (excessive or insufficient refrigerant amount). is there. Furthermore, these two probability density functions are assumed to be known and are generally considered to be normal distributions. Therefore possible to assay, it is reduced to that of finding the boundaries A _B in Fig.

When making the above two types of error judgments, determine the amount of damage for each. The damage when E ₀ is committed is C ₀ , and the damage when E ₁ is committed is C ₁ . If the probability P of refrigerant leakage is known a priori, it may also be used to define the total average danger level, which is the sum of the damages, as shown in the following equation. P can be said to be an a priori probability, and a value is obtained in advance together with the previous probability density function.

The boundary value A _B is determined so as to minimize the above formula. It is only necessary to obtain dC (A _B ) / dA _B = 0.

Given in. The ratio of the left side of Equation (10) is a likelihood ratio, and the value of the right side is a threshold value. When the likelihood ratio exceeds a threshold value, and accepting the hypothesis H _1, the air conditioner is abnormal, i.e. it determines that the refrigerant amount excess-deficient, if less than the threshold value, it is determined that normal.

  First, since the probability density function is generally considered to be a normal distribution and assumed to be acceptable, the probability density function is

And In this case, A _B that minimizes Equation (9), that is, A _B that satisfies Equation (10) is

It becomes. If it is difficult to obtain the probability of refrigerant leakage or the magnitude of damage C ₀ , C _1, as a special case, if P = ½ and C ₀ = C ₁ , then A _B = (A ₀ + A ₁ ) / 2. Then, the fact that it put the A _B to a value that exactly the arithmetic mean.

  As described above, the refrigerant quantity determination with higher accuracy can be performed by estimating the dynamic characteristic coefficient of the air conditioner from the detection signal of the normal operation state of the air conditioner and performing the verification process. This test process can also be used in the following examples.

<Post-processing of refrigerant quantity determination>
After performing the refrigerant amount determination, the contents such as the user name of the device, the installation area and location, and the refrigerant state are displayed on the use source display device 64 and the product supply source display device 66 via the communication means 67. It is desirable that the display device is installed in the air conditioner itself, or installed in the use source, service center, or manufacturing factory to transmit information to various places. If the cooling capacity is expected to be reduced or the air conditioner is damaged due to the refrigerant leakage, the service person can rush to the site as soon as possible to take the best measures such as identifying the location of the refrigerant leakage and refilling the refrigerant. This post processing can also be used in the following examples.

FIG. 9 is a flowchart of refrigerant amount determination in the present embodiment. When the measurement of the dynamic characteristic is used for the determination of the refrigerant amount, even if an operation is applied to the past state quantity, there is a difference between the expected state quantity and the actual state quantity, and for example, the estimated value b is found to be small. And it may be determined that the refrigerant is leaking. However, if the outdoor bypass expansion valve 291 or 29N stops moving due to a firm traffic or the like, the amount of refrigerant flowing through the flow path will not increase even if the opening degree of the outdoor bypass expansion valve is controlled to increase. In some cases, the state quantity S _C is not obtained, and it is erroneously determined that the refrigerant is leaking. That is, it cannot be determined whether the refrigerant leaks or the outdoor bypass expansion valve fails.

Therefore, the compressor discharge superheat degree calculated by the compressor discharge temperature detectors 531 and 53N and the compressor discharge pressure detectors ₅₇₁ and _57N is _defined as T _dSH , which is a state quantity influenced by the outdoor bypass expansion valve ( When expressed similarly to 1), it is as follows.

Here, d _{1 to} d _p , f _{1 to} f _q , p, q are constants. The control arithmetic unit 62 identifies these coefficients d _{1 to} d _p and f _{1 to} f _q during operation, and constantly monitors the values. At the time of determining the refrigerant amount, attention is first paid to the compressor discharge superheat degree T _dSH of the equation (13). The estimated values of the coefficients identified for d _{1 to} d _p and f _{1 to} f _q are
Hereinafter, these are referred to as an estimated value d and an estimated value f, respectively.

The estimated value f is a correlation value having a correlation with the state quantity (compressor discharge superheat degree) based on the outdoor bypass expansion valve operation amount, and can also be referred to as state quantity sensitivity. When refrigerant leakage, but this reduction in the estimated value f is reflected in the value of T _DSH, completely no point sensitivity is eliminated it is different from the case of S _C. Therefore, in order to confirm whether or not the outdoor bypass expansion valve is tight, the control arithmetic unit 62 fixes the opening degree of the indoor expansion valves 441 and 44N so that the temperature of the suction portion and the discharge portion of the compressor does not fluctuate. Then, system identification is newly performed for d ₁ to d _p and f _{1 to} f _q to obtain the estimated value d and the estimated value f. If the estimated value f is 0, the expansion valve is faulty and the estimated value f is 0. If it is not, it is determined that there is no failure in the expansion valve itself.

On the outdoor bypass expansion valve is confirmed not to be a failure, the next step is to focus on again S _C. Since the subsequent refrigerant amount determination is the same as that of the first embodiment, it is omitted. FIG. 9 shows only the case of refrigerant leakage.

According to the present embodiment, the coefficients d _{1 to} d _p and f _{1 to} f _q for the compressor discharge superheat T _dSH are _first identified, and the manipulated variable e _B (k−1) to e _B (k−q). determining the amount of refrigerant used after determining whether the state of sensitivity and which estimates the expansion valve using the f is faulty, the estimated value b for the supercooling heat exchanger outlet supercooling degree S _C for To do. As a result, it is possible to first determine whether the cause of the failure is a failure or a refrigerant leak, and the stable state of the refrigeration cycle at the time of determination is unnecessary, and it can be determined even during normal operation.

  As post processing, not only information on refrigerant leakage but also information on failure of the outdoor bypass expansion valve may be displayed on the display devices 64 and 66 via the communication means 67. Information may be transmitted to a service center or the like. As a result, the user or service person can quickly know the failure and take immediate action. Post processing for failures can also be used in the following examples.

FIG. 10 is a refrigeration cycle diagram in the present embodiment. In the first embodiment, the relationship between the supercooling heat exchanger outlet supercooling degree S _C and the outdoor bypass expansion valve has been described based on the outdoor bypass expansion valve 291,29N and the supercooling heat exchanger 301, There may be no case of 30N. As subcooling the S _C of Example 1 in the outdoor heat exchanger outlet, the outdoor heat exchanger outlet supercooling degree S _C and the outdoor expansion valve refrigerant quantity similarly be replaced with the relationship between the degree of opening of 281,28N Judgment can be made. However, in this case, the indoor expansion valves 441 and 44N have fixed opening degrees. An outdoor heat exchanger outlet supercooling degree S _C is detected by the outdoor heat exchanger outlet temperature sensor 542,542N.

Outdoor bypass expansion valve used in Example 1, S _C increases it means that the heat exchange with the more subcooling heat exchanger when increasing the flow rate by increasing the opening degree. In contrast, the outdoor expansion valve used in this embodiment is the smaller the opening, that S _C is increased is different because the refrigerant circulating refrigerant flow rate is decreased is that sufficient outside air heat exchange. However, also in this embodiment, exhibits the same tendency as FIG. 4, if the outdoor expansion valve opening is constant, because insufficient amount of the refrigerant heat exchange with the amount of refrigerant is small, the value of S _C becomes smaller The same is true. When FIG. 5 is replaced with the present embodiment, “decreasing the flow rate ratio” corresponds to “increasing the opening degree of the outdoor expansion valve”. Thus, for example, when the refrigerant is leaked, the value of S _C becomes smaller with the same opening, estimate b of the state quantity based on the operation amount is reduced and the refrigerant by observing the variation ΔB in this estimate b Leakage can be determined. That is, the increase or decrease in the refrigerant amount can be determined as in the first embodiment. However, in this embodiment using the outdoor expansion valve, it is determined that the refrigerant amount increases if ΔB increases, and the refrigerant amount decreases if ΔB decreases. Is done. Similar to the first embodiment, it is possible to determine whether or not the refrigerant amount is excessive by obtaining the estimated value b itself.

  Even when the refrigerant amount is determined not by the outdoor bypass expansion valves 291 and 29N but by the opening operation of the outdoor expansion valves 281 and 28N, an erroneous determination of refrigerant leakage may occur. In other words, even if the refrigerant is not leaking and the outdoor expansion valve itself is stiff and does not move in response to the command, there is a difference between the state quantity expected from the operation amount and the actual state quantity, and apparently, For example, the estimated value b may be determined to be small, and it may be erroneously determined that the refrigerant is leaking.

Accordingly, attention is paid to the compressor discharge superheat degree T _dSH of the expression (13) as a state quantity that the outdoor expansion valve affects. The control arithmetic unit 62 identifies these coefficients d _{1 to} d _p and f _{1 to} f _q during operation, and constantly monitors the values. At the time of determining the refrigerant amount, attention is first paid to the compressor discharge superheat degree T _dSH of the equation (13). Estimates if like the coefficient S _C f has a correlation with the amount state based on the outdoor expansion valve operation amount (compressor discharge superheat) can be also referred to as the sensitivity of the state quantity. When the amount of refrigerant is reduced, although this decrease in the estimated value is reflected in the value of T _DSH, completely no point sensitivity is eliminated it is different from the case of S _C. Therefore, in order to check whether the outdoor expansion valve is tight, the control arithmetic unit 62 fixes the opening degree of the indoor expansion valves 441 and 44N so that the temperature of the suction part and the discharge part of the compressor does not fluctuate. Then, system identification is newly performed for d ₁ to d _p and f _{1 to} f _q to obtain the estimated value d and the estimated value f. If the estimated value f is 0, the expansion valve is faulty and the estimated value f is other than 0. If it is, it is determined that there is no failure in the expansion valve itself.

On the outdoor expansion valve is confirmed not to be a failure, the next step is to focus on again S _C. Subsequent refrigerant quantity determinations are the same as in Example 3, and are therefore omitted.

According to this embodiment, first, coefficients d _{1 to} d _p and f _{1 to} f _q for the compressor discharge superheat degree T _dSH are identified, and the expansion valve is used by using the estimated value f that is the sensitivity of the state quantity with respect to the manipulated variable. There after determining whether the failure to identify the coefficients _{a 1 ~a n, b 1 ~b} m for S _C. As a result, it is possible to first determine whether the cause of the failure is a failure or a refrigerant leak, and the stable state of the refrigeration cycle at the time of determination is unnecessary, and it can be determined even during normal operation.

DESCRIPTION OF SYMBOLS 1 Operation start part 2 Air conditioner starting part 3 Normal control part 5 Online system identification process part 6 Coefficient parameter determination part 7 Data initialization part 8 Expansion valve solid astringency determination part 9 Expansion valve solid astringency recognition part 10 Refrigerant amount determination part 11 Refrigerant amount excess recognition unit 13 Refrigerant amount appropriateness recognition unit 16 Refrigerant amount underrecognition units 17, 19 Display command unit 18 Communication processing unit 20 Alarm stop processing unit 21 Refrigerant amount increase recognition unit 22 Refrigerant amount decrease recognition unit 23 Refrigerant amount maintenance recognition unit 33 Outdoor unit side liquid side branch part 34 Outdoor unit side gas side branch part 35 Liquid side pipe 36 Gas side pipe 37 Indoor unit side liquid side branch part 38 Indoor unit side gas side branch part 62 Control arithmetic device 63 Information storage device 64 Use Original display device 65 Information input device 66 Product supplier display device 67 Communication means 68 Coefficient identification value 69 by online system identification True value 70 Normal range 71 Normal determination region 72 Abnormal Constant region 73 Probability density function with normal condition 74 Probability density function with abnormal condition 75 Type 2 error probability 76 Type 1 error probability 86 Test processing unit 87 Test refrigerant amount determination unit 211, 21N Outdoor unit 221, 22N Compressor 231 23N Outdoor heat exchanger 241, 24N Outdoor fan 251, 25N Accumulator 261, 26N Four-way valve 271, 27N Receptor 281, 28N Outdoor expansion valve 291, 29N Outdoor bypass expansion valve 292, 292N Bypass piping 301, 30N Supercooling heat exchanger 311, 31N Outdoor unit side liquid side piping 321, 32N Outdoor unit side gas side piping 391, 39M Indoor unit side liquid side piping 401, 40M Indoor unit side gas side piping 411, 41M Indoor unit 421, 42M Indoor heat exchanger 431 43M Indoor fan 441, 44M Indoor expansion valve 451, 45N Inverter compression Frequency controller 461, 46N Outdoor fan blower capacity controller 471, 47N Outdoor expansion valve opening controller 481, 48N Outdoor bypass expansion valve opening controller 491, 49N Four-way valve controller 501, 50M Indoor fan blower capacity controller 511 , 51M Indoor expansion valve opening controller 521, 52N Compressor intake temperature detector 531, 53N Compressor refrigerant discharge temperature detector 541, 54N Subcooling heat exchanger outlet temperature detector 542, 542N Outdoor heat exchanger outlet temperature detection 551,55N Outdoor temperature detector 561,56N Compressor suction pressure detector 571,57N Compressor discharge pressure detector 581,58M Indoor unit suction temperature detector 591,59M Indoor unit outlet temperature detector 601,60M Setter 611, 61M User Department

Claims (10)

In a refrigeration cycle apparatus in which a compressor, an outdoor heat exchanger, and a supercooling heat exchanger are connected by piping,
An outdoor bypass expansion valve provided in a bypass pipe connected to a pipe on the suction side of the compressor from a pipe between the outdoor heat exchanger and the supercooling heat exchanger;
A supercooling heat exchanger outlet temperature detector for measuring the degree of supercooling heat exchanger outlet supercooling at the outlet of the supercooling heat exchanger;
The operation amount of the outdoor bypass expansion valve e _B (k-1) and ~e _B (k-m), the supercooling heat exchanger outlet to k time step before the change supercooling degree S _C (k-1) ~ S _C (k-n), the supercooling heat exchanger outlet supercooling degree after the change based on these S _C (k) parameter from the following equation using the ARX model during normal operation a ₁ ~a _n, b A control arithmetic unit that identifies estimated values of _{1 to} b _m ,
The refrigeration cycle apparatus characterized in that the control arithmetic device determines a refrigerant amount using estimated values of the parameters b _{1 to} b _m . 2. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant is determined to be leaking when a change amount of the estimated values of the parameters b _{1 to} b _m is positive. The control arithmetic device according to claim 1 or 2,
The compressor discharge superheat degree T _dSH is obtained from the discharge temperature and discharge pressure of the compressor,
The operation amount of the outdoor bypass expansion valve _{e B (k-1) ~e} B (k-m) and, the compressor discharge superheating degree T _DSH to k time step before the change (k-1) ~T _dSH ( k-n), the following equation using the ARX model parameters d ₁ to d _p, of f ₁ ~f _q from from the compressor discharge superheating degree T _DSH after the change based on these (k) during normal operation A control arithmetic unit for identifying the estimated value,
When the estimated values of the parameters b _{1 to} b _m are other than 0 and the amount of change in the estimated values of the parameters b _{1 to} b _m is positive, it is determined that the refrigerant is leaking. A refrigeration cycle device. According to claim 3, wherein the parameter f ₁ ~f _q estimate refrigeration cycle apparatus characterized said determining that the outdoor bypass expansion valve is faulty if becomes 0. 5. The refrigeration cycle apparatus according to claim 1, wherein when the amount of change in the estimated values of the parameters b _{1 to} b _m is negative, it is determined that the refrigerant is increasing. 6. The refrigeration cycle apparatus according to claim 1, wherein when the estimated values of the parameters b _{1 to} b _m are equal to or greater than a predetermined value, it is determined that the refrigerant is leaking. In a refrigeration cycle apparatus in which a compressor, an outdoor heat exchanger, and an outdoor expansion valve are connected by piping,
An outdoor heat exchanger outlet temperature detector for measuring the degree of subcooling of the outdoor heat exchanger outlet at the outlet of the outdoor heat exchanger;
The outdoor expansion valve operation amount _{e B (k-1) ~e} B (k-m) and the outdoor heat exchanger outlet to k time step before the change supercooling degree S _C (k-1) ~S _C (k-n), the parameters a ₁ from the following equation using the ARX model from the outdoor heat exchanger outlet supercooling degree after the change based on these S _C (k) during normal operation ~a _n, b ₁ ~ a control arithmetic unit for identifying an estimated value of b _m ,
The refrigeration cycle apparatus characterized in that the control arithmetic device determines a refrigerant amount using estimated values of the parameters b _{1 to} b _m . 8. The refrigeration cycle apparatus according to claim 7, wherein it is determined that the refrigerant is leaking when a change amount of the estimated values of the parameters b _{1 to} b _m is negative. In any of claims 1 to 8,
A refrigeration cycle apparatus comprising a display device for displaying a determination result by the control arithmetic device. In any one of Claims 1 thru | or 9,
A refrigeration cycle apparatus comprising: a communication unit configured to communicate a determination result to a service center when the control arithmetic device determines that the refrigerant leaks or malfunctions.