JPH05264089A - Defrosting controller for freezer - Google Patents

Abstract

PURPOSE:To eliminate an error of a judging timing due to a variation in a frequency of an inverter in a defrosting controller for judging a defrosting starting timing of a freezer at a decreasing time point of mean room heating capacity. CONSTITUTION:A compressor 1 with an inverter is disposed in a freezer, and a temperature difference DELTATn between an outlet temperature To and an inlet temperature Ti of a user side heat exchanger 6 is calculated at each predetermined period. With a predetermined frequency for giving a temperature difference corresponding to room heating capacity as a reference, a correction coefficient XD5 for converting the difference DELTAT into a value at the predetermined frequency is used as a function of the frequency, and stored in a correction formula memory means 12 at each type of the compressor. The difference DELTATn is corrected with the coefficient XD5 to obtain a temperature difference DELTATnh to become an accurate index of the room heating capacity. Integrated room heating capacity Sn and mean room heating capacity Qn are calculated based on the corrected difference DELTATnh, and a defrost command is output by defrosting command output means 55 when the mean room heating capacity Qn is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrosting operation control device for a refrigeration system, and more particularly to an improvement of a defrosting operation control device which starts defrosting operation based on a change in average heating capacity.

[0002]

2. Description of the Related Art Conventionally, as a defrosting operation control device for a refrigerating machine, a refrigerating machine having a compressor whose operating frequency is variably adjusted by an inverter, as disclosed in, for example, JP-A-64-41748. In the equipment, the outlet-inlet temperature difference of the medium to be heated of the utilization side heat exchanger is periodically calculated, and it is calculated in advance on the basis that this temperature difference fluctuates as the inverter frequency decreases and decreases as the inverter frequency increases. The relationship of the correction coefficient with respect to the frequency is stored as function information, and the cumulative heating capacity from the heating operation start time immediately after defrosting is set as the correction coefficient corresponding to the outlet-inlet temperature difference and the frequency at that time. It is calculated and stored periodically based on the value obtained by multiplying by, and this cumulative rod capacity is set as the estimated heating time from the heating operation start time to the present time. The average heating capacity is calculated by dividing by the sum of the operating time, the current value of this average heating capacity is compared with the previous value, and the defrost signal is output when this value is small. Those are known techniques.

[0003]

DISCLOSURE OF THE INVENTION The defrosting operation control device for a refrigerating apparatus disclosed in the above-mentioned conventional publication detects the frosted state of the utilization side heat exchanger due to a decrease in heating capacity,
It is intended to set the optimum defrosting start timing. That is, as shown in FIG. 7, the outlet-inlet temperature difference ΔTn of the medium to be heated is measured, and the heating capacity Q during the period Δt is measured.
When m is calculated, it becomes Qm = Δt · ΔTn, which is the time t from the start of heating operation after the defrosting operation is completed.
The cumulative heating capacity Sn until the elapse of f is expressed by the following formula Sn = ΣQm (see the shaded area in FIG. 8). Therefore, the average heating capacity Qn between the heating operation time tf and the predicted defrosting operation time tdy is represented by the following formula Qn = Sn / (tf + tdy) (However, in the figure, the previous defrosting operation is performed. The time is defined as the predicted defrosting operation time tdy).

Then, as shown in FIG. 9, when the average heating capacity Qn up to that time is periodically obtained during the heating operation and its change is plotted, the average heating capacity Qn increases as the heating operation progresses. However, when frost is formed on the heat source side heat exchanger, the heating capacity is reduced accordingly, so that the average heating capacity Qn is lowered (see point Qe in FIG. 9).
At this point, by outputting the defrosting command, it is possible to accurately determine the rush time to the defrosting operation.

Particularly, in the above-mentioned conventional one, the outlet-inlet temperature difference ΔTn of the medium to be heated is complicatedly changed depending on the inverter frequency, that is, the operating capacity of the compressor, and the apparent cumulative heating capacity Sn is increased / decreased due to the influence. In consideration of this, by correcting the outlet-inlet temperature difference by the inverter frequency,
It is intended to improve the defrosting control accuracy and eventually the EER.

In this case, the relation between the inverter frequency and the correction coefficient was based on the change characteristic of the outlet-inlet temperature difference with respect to the inverter frequency obtained by the experiment of the refrigerating apparatus, but actually, the characteristic of various refrigerating apparatuses is changed. However, there is a problem that it is inconvenient to apply it as it is.

The present invention has been made in view of the above point, and an object thereof is that the outlet temperature of the medium to be heated of the utilization side heat exchanger changes according to the condensation temperature of the utilization side heat exchanger. When the outlet-inlet temperature difference of the heat exchanger on the use side changes according to the condensing temperature of the refrigerant, and the condensing temperature also changes according to the inverter frequency, and when the model such as the rated capacity of the compressor is determined, it depends on the inverter frequency. Focusing on the fact that the change characteristic of the outlet-inlet temperature difference is almost constant, formulating the relationship between the inverter frequency and the correction coefficient with a regression equation determined by the model of the compressor simplifies the application to each refrigeration system. Is to try.

[0008]

Means for Solving the Problems To achieve the above object, the means of the invention of claim 1 is, as shown in FIG. 1, a compressor (1) whose frequency is variably adjusted by an inverter, Heat source side heat exchanger (3) and pressure reducing mechanism (5)
It is premised on a refrigerating apparatus provided with a refrigerant circuit (9) in which the above and the use side heat exchanger (6) are sequentially connected.

As a defrosting operation control device for the refrigeration system, an inlet temperature detecting means (Thr) for detecting the inlet temperature (Ti) of the medium to be heated of the utilization side heat exchanger (6) and the utilization side heat. Outlet temperature (To) of heated medium of exchanger (6)
The outlet temperature detecting means (The) for detecting the temperature and the outputs of the both temperature detecting means (Thr), (The) are received, and the outlet temperature (To) and the inlet temperature (Ti) during the heating operation are set at regular intervals. Difference between outlet and inlet (ΔTn)
Based on the correlation between the inverter frequency (Hz) and the condensing temperature, the temperature difference calculating means (51) is used as a reference, and the temperature difference calculating means (51) is used as a reference. 51) The model of the compressor (1) is a correction coefficient (XD5) for converting the outlet-inlet temperature difference (ΔTn) calculated in 51) into the outlet-inlet temperature difference at the predetermined frequency as a function of the inverter frequency (Hz). A correction formula storage means (12) for storing each of the correction formula storage means (12) and an outlet-inlet temperature difference (ΔTn) calculated by the temperature difference calculation means (51) according to the inverter frequency (Hz). The correction means (52) for correcting by the correction coefficient (XD5) stored in and the cumulative heating capacity (Sn) from the start of heating operation after the end of defrosting are corrected by the correction means (5).
Integrated heating capacity calculation means (53) for periodically calculating based on the outlet-inlet temperature difference (ΔTnh) corrected in 3)
And the heating operation time (t
The average heating capacity (Q) is calculated by dividing the integrated heating capacity (Sn) calculated by the integrated heating capacity calculation means (53) by the sum of f) and the set predicted defrosting operation time (tdy).
n) and an average heating capacity calculation means (54), and a current calculated value (Qk) of the average heating capacity (Qn) calculated by the average heating capacity calculation means (54) is changed to a previous calculated value (Qk-
Compared to 1), a defrost signal output means (55) for outputting a defrost signal when the calculated value this time is small is provided.

As shown by the broken line portion in FIG. 1, the means taken by the invention of claim 2 is, in addition to the invention of claim 1, the temperature difference (ΔTnh) corrected by the correction means (52) is negative. In this case, the re-correction means (56) for re-correcting the temperature difference to "0" is provided.

[0011]

With the above construction, in the invention of claim 1, the integrated heating capacity calculating means (53) and the average heating capacity calculating means (53) are calculated based on the outlet-inlet temperature difference ΔTn (= To-Ti) of the medium to be heated. 54) the integral heating capacity Sn and the average heating capacity Qn are calculated, and the defrosting signal output means (55) reduces the heating capacity from the peak value of the average heating capacity by frosting the heat source side heat exchanger (3). The defrosting start time is determined and the defrosting command is issued.

On the other hand, the correction-type storage means (12) stores the outlet-inlet temperature difference ΔTn at the predetermined frequency with the outlet-inlet temperature difference ΔTn as a reference, based on a predetermined frequency of the inverter that gives the outlet-inlet temperature difference corresponding to the heating capacity. A correction formula for converting into the above is stored as a function of the inverter frequency Hz, and the outlet-inlet temperature difference ΔTn is corrected by the correction means (53) according to the inverter frequency using the correction coefficient XD5 obtained by this correction formula. Therefore, the corrected outlet-inlet temperature difference ΔTnh is an accurate indicator of the heating capacity.
Then, since the integrated heating capacity Sn and the average heating capacity Qn are calculated based on the outlet-inlet temperature difference ΔTnh corrected based on the regression equation (1), the defrosting caused by the change in the condensation temperature due to the inverter frequency is calculated. The start of the defrosting operation can be determined without causing an erroneous determination of the entry time.

According to the invention of claim 2, in the operation of the invention of claim 1, when the outlet-inlet temperature difference ΔTnh corrected by the correcting means (52) becomes negative, the re-correcting means (5
Since the outlet-inlet temperature difference ΔTnh is re-corrected to “0” by 6), the error in calculation of the average heating capacity Qn occurs due to the reversal of the outlet temperature To and the inlet temperature Ti that may occur under special conditions, and the removal is eliminated. It is possible to prevent the rush time to the frost operation from being mistaken, and to more accurately determine the rush time to the defrost operation.

[0014]

Embodiments of the present invention will be described below with reference to the drawings starting from FIG.

FIG. 2 shows a refrigerant piping system of an air conditioner to which the present invention is applied, which is a so-called separate type in which one outdoor unit (A) is connected to one indoor unit (B). is there. The outdoor unit (A) is switched to a compressor (1) whose operating frequency is variably adjusted by an inverter (not shown), and a solid line in the drawing during the cooling operation and a broken line in the drawing during the heating operation. A four-way switching valve (2), an outdoor heat exchanger (3) that is a heat source side heat exchanger that functions as a condenser during cooling operation, and as an evaporator during heating operation, and a decompression unit (2) for decompressing refrigerant.
0) and an accumulator (7) which is interposed in the suction pipe of the compressor (1) and removes the liquid refrigerant in the suction refrigerant are arranged as main devices. Further, in the indoor unit (B), an indoor heat exchanger (6), which is a utilization side heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation, is arranged. The above-mentioned devices are sequentially connected by a refrigerant pipe (8), and a refrigerant circuit (9) is configured so that heat is transferred by circulating the refrigerant.

Here, the pressure reducing section (20) includes a receiver (4) for storing the liquid refrigerant and an electric expansion valve (5) having a pressure reducing function and a flow rate adjusting function for the liquid refrigerant. The receiver (4) and the electric expansion valve (5) are disposed so that the electric expansion valve (5) communicates with the lower portion of the receiver (4), that is, the liquid portion. ) Auxiliary heat exchanger (3a)
Are arranged in series on the common path (8a). Then, between the outdoor end (P) of the receiver (4) upstream of the common path (8a) and the outdoor heat exchanger (3), the outdoor heat exchanger (3) goes to the receiver (4). Between the point (P) of the common path (8a) and the indoor heat exchanger (6) by the first inflow path (8b1) via the first check valve (D1) that allows only the circulation of the refrigerant of Is from the indoor heat exchanger (6) to the receiver (4)
The electric expansion valve (5) and the like on the common path (8a), while being connected to each other by the second inflow path (8b2) through the second check valve (D2) that allows only the flow of the refrigerant to the Between the end portion (Q) on the end side and the point (R) between the second check valve (D2) and the indoor heat exchanger (6), the electric expansion valve (5) is connected to the indoor heat exchanger (6). The first check valve (D1) and the point (Q) of the common path (8a) by the first outflow passage (8c1) through the third check valve (D3) that allows only the flow of the refrigerant to the first check valve (D1). A fourth check valve (D4) which allows only the flow of the refrigerant from the electric expansion valve (5) to the outdoor heat exchanger (3) between the outdoor heat exchanger (3) and the point (S). Through the 2nd outflow path (8c2)
Are connected to each other.

Further, a capillary tube (C) is provided between the point (P) on the upstream side and the point (Q) on the outflow side of the receiver (4) to prevent liquid sealing. Bypass road (8f)
Is provided, and it is essential to prevent liquid sealing when the compressor (1) is stopped by the liquid sealing prevention bypass passage (8f). In addition, the bypass pipe (by which the gas refrigerant is bypassed from the upper portion of the receiver (4) to the downstream side of the electric expansion valve (5) via the on-off valve (SV) to ensure the refrigerant reservoir function of the receiver (4) ( 4a) is provided. The degree of pressure reduction of the capillary tube (C) is set to be sufficiently larger than that of the electric expansion valve (5),
The function of adjusting the refrigerant flow rate by the electric expansion valve (5) during normal operation can be favorably maintained.

Incidentally, (F1) to (F4) are filters for removing dust in the refrigerant, and (ER) is a silencer for reducing the operation noise of the compressor (1).

Further, the air conditioner is provided with sensors, (Th2) is arranged in the discharge pipe, a discharge pipe sensor for detecting the discharge pipe temperature, and (Tha) is the air intake of the outdoor unit (A). The outdoor suction sensor (Thc), which is placed at the mouth and detects the temperature of the intake air that is the outside air temperature, (Thc) is placed in the outdoor heat exchanger (3), and has the condensation temperature during the cooling operation and the evaporation temperature during the heating operation. An outdoor heat exchange sensor for detecting the temperature, (Thr) is arranged in the air suction port of the indoor unit (B), and an indoor suction sensor for detecting the suction air temperature Ti which is the inlet temperature of the medium to be heated, (The) is the indoor An internal heat exchange sensor that is arranged in the heat exchanger (6) and detects the internal heat exchange temperature that becomes the condensation temperature during the heating operation as the outlet temperature To of the medium to be heated, (HPS) is turned on due to an excessive rise in the high-pressure side pressure. The protection device ( 1 high pressure switch, which actuates the) (LPS) is a low pressure switch for actuating the protective device (11) turned on by excessive reduction of the low-pressure side pressure. The signals of the sensors are connected to a controller (10) that controls the operation of the air conditioner, and the controller (10) operates the air conditioner according to the signals of the sensors. Is designed to control.

Here, the controller (10) includes
Storage device (11) as correction formula storage means for storing a relational expression between an inverter frequency Hz and a correction coefficient XD5 described later.
Also, an arithmetic circuit (12) for arithmetically processing various data during operation is incorporated. In the storage device (12), the correction coefficient XD5 is preset as a function of the inverter frequency Hz, as in the following mathematical expression (1) XD5 = A + B · Hz + C · Hz ² (1). Then, this formula (1)
The coefficients A, B, and C of each term are determined by the model such as the rated capacity of the compressor. For example, a quadratic regression curve (xo) as shown in FIG.
It is determined by (x1).

For example, in the case of a quadratic regression curve (x1), when the inverter frequency Hz is 60 (Hz) (point X1),
Since the outlet-inlet temperature difference ΔTn gives an accurate heating capacity, the correction coefficient XD5 becomes almost "1". Then, based on this frequency value of 60 (Hz), the inverter frequency H
It is obtained by plotting a correction coefficient XD5 for converting the outlet-inlet temperature difference ΔTn when z changes to the outlet-inlet temperature difference when the inverter frequency is 60 (Hz). It becomes a quadratic regression curve,
It is also possible to use a higher-order regression equation of third or higher order. In the curve (xo), the frequency value at the point (Xo) becomes the predetermined frequency.

In the refrigerant circuit (9), during the cooling operation, the liquid refrigerant condensed and liquefied in the outdoor heat exchanger (3) flows in from the first inflow passage (8b1), and the first check valve (D1) is turned on. After being stored in the receiver (4) and decompressed by the electric expansion valve (5), it is evaporated in the indoor heat exchanger (6) through the first outflow passage (8c1) and returned to the compressor (1). While becoming a cycle,
During the heating operation, the liquid refrigerant condensed and liquefied in the indoor heat exchanger (6) flows in from the second inflow passage (8b2), is stored in the receiver (4) via the second check valve (D2), After the pressure is reduced by the electric expansion valve (5), it is circulated through the second outflow passage (8c2) to evaporate in the outdoor heat exchanger (3) and return to the compressor (1).

At this time, the opening degree of the electric expansion valve (5) is set with the discharge pipe temperature T2 detected by the discharge pipe sensor (Th2) as a parameter. That is, the discharge pipe temperature (optimum temperature Tk) that gives the optimum refrigerating effect is calculated from the condensation temperature and the evaporation temperature detected by the external heat exchange sensor (Thc) and the internal heat exchange sensor (The), and the discharge pipe temperature is calculated. The opening of the electric expansion valve (5) is controlled so that T2 becomes the optimum temperature Tk.

When the defrosting command is received during the heating operation, the four-way switching valve (2) is switched to the cooling cycle side,
Hot gas is introduced into the outdoor heat exchanger (3) to melt the frost formed on the outdoor heat exchanger (3).

Next, the control contents during the heating operation will be described based on the flowchart of FIG.

In step ST1, it is determined whether or not it is in the operating state. If it is not in the operating state, the heating operation time count value tfs is set to "0" in step ST2, and if it is in the operating state, control from step ST3 onward is performed. .. First, steps ST3 and S
At T4, the heating operation time tf is counted, and at step ST5, a temperature difference ΔTn (= To-Ti) between the air outlet temperature To and the air intake temperature Ti is calculated, and step ST6
Then, the correction coefficient XD5 is calculated based on the correction equation XD5 = f (Hz) determined by the above equation (1).

Then, in step ST7, ΔTnh = ΔT
n / XD5, that is, the temperature difference ΔTn obtained in step ST5 is corrected by the correction coefficient XD5, and the value is set as the corrected temperature difference ΔTnh. In steps ST8 and ST9, a process of setting the calculated value when the temperature difference ΔTnh becomes negative depending on the operating conditions to “0” is performed, and then in step ST10.
Then, the cumulative heating capacity Sn is added.

Next, in step ST11, the flag Flg which becomes "0" only in the first cycle after the start of operation is determined, and if it is the first cycle, step ST12.
Then, the average heating capacity Qn is calculated based on the following equation (2) Qn = Sn / (td + tf) (2). In this case, since the defrosting has not been performed yet, the set defrosting time t
The cumulative heating capacity Sn is divided by the sum of d (for example, about 5 minutes) and the heating operation time tf.

On the other hand, from the next cycle after the defrosting, the flag Flg becomes "1" in the determination in step ST11, the process proceeds to step ST13, and
(3) Calculate the predicted defrosting operation time tdy based on tdy = a · tf + 1 (3). However,
The coefficient a is calculated from the previous heating operation time tu and the previous defrosting operation time td, assuming that the time lag required for switching the function of the evaporator-condenser in switching between defrosting and heating is approximately 1 minute, Equation (4) a = (td -1) / tu (4)

Next, in steps ST14 to ST17, in consideration of safety, the predicted defrosting is performed in order to prevent the calculation result from being too far from the previous defrosting operation time td due to an erroneous detection of the sensor or the like. The lower limit of the operating time tdy is 0.5td
And the upper limit of 1.5td, step ST1
In step 8, the average heating capacity Qn is calculated based on the following equation (5) Qn = Sn / (tdy + tf) (5).

Next, by the above control, the average heating capacity Qn
When is calculated, the process proceeds to the determination control of the entry time to the defrosting operation. FIG. 4 shows the content of the judgment control of the entry time to the defrosting operation, and in step SS1, the average heating capacity Qk calculated in this control is compared with the average heating capacity Qk-1 calculated in the previous control, If Qk≤Qk-1 is not established, the process proceeds to step SS2, the reduction count value CD1 is subtracted from CD1 = CD1-1, and if CD1 is not negative in steps SS3 and SS4, the value remains unchanged. The process of setting to "0" is performed, and the process returns to the control of step SS1 without outputting the defrosting operation command.

On the other hand, in the judgment of step SS1, Qk≤Q
At k-1, since the average heating capacity Qn decreased,
The process proceeds to step SS5 to count the decrease count value CD1, and in the determination of step SS6, the above control is repeated without issuing a defrosting operation command until CD1 reaches 10 times or more, and CD1 ≧ 10. Then, step SS7
Then, it is determined that CD1 = 10, that is, the average heating capacity has reached the peak, and the defrosting operation command is output.

In the above flow, the temperature difference calculating means (51) is constituted by the control of step ST5, the correction means (52) is constituted by the control of step ST7, and the integral heating capacity calculating means (5) is constituted by the control of step ST10.
3) is configured, the average heating capacity calculation means (54) is configured by the control of step ST10, and the defrost signal output means (55) is configured by the control of step SS8.

Further, the recorrecting means (56) according to the invention of claim 2 is constituted by the control of step ST9.

Therefore, in the above embodiment, the integrated heating capacity calculating means (53) and the average value are calculated based on the temperature difference ΔTn (= To-Ti) between the outlet temperature To and the inlet temperature Ti of the medium to be heated during the heating operation. The heating capacity calculation means (54) calculates the integral heating capacity Sn and the average heating capacity Qn,
The defrosting signal output means (55) determines the defrosting start time when the heat source side heat exchanger (3) is defrosted from the peak value of the average heating capacity, and the defrosting command is issued. Done.

At this time, in the case where the compressor (1) whose frequency is variably adjusted by the inverter is provided, the compressor (1)
When the capacity of is changed, the refrigerant circulation amount is changed and the condensing temperature of the refrigerant in the indoor heat exchanger (6), which is the condenser, that is, the outlet temperature To of the heated medium is changed.
The outlet-inlet temperature difference ΔTn also changes, and the outlet-inlet temperature difference ΔTn
Tn is not always an accurate indicator of heating capacity.
That is, as shown in FIG. 6, the average heating capacity Qn is calculated to be apparently smaller (broken curve q1) or larger than the true change (solid curve qo) (broken curve q2).
). Since the rushing timing for the defrosting operation is determined based on this average heating capacity Qn, there is a risk of rushing into the defrosting operation at a time deviated from the time of true frost formation (time point Q1e or Time point Q2e).

Here, in the above embodiment, the correction means (5
According to 2), the temperature difference ΔTn is corrected by using the correction coefficient XD5 obtained by the quadratic regression equation (1) stored in advance in the storage device (12) as a function of the inverter frequency Hz. -The inlet temperature difference ΔTnh is an accurate indicator of heating capacity. Then, since the integrated heating capacity Sn and the average heating capacity Qn are calculated based on the outlet-inlet temperature difference ΔTnh corrected based on this regression equation (1), it is possible to accurately determine the start of the defrosting operation. It is possible (time point Qoe in the figure).

Further, when the outlet-inlet temperature difference ΔTnh corrected by the correcting means (52) becomes negative by the re-correcting means (56), it is corrected to "0" to further improve the calculation accuracy. .. For example, immediately after returning from the defrost operation, the intake air temperature Tr may be lower than the condensation temperature Tc. In such a case, the outlet-inlet temperature difference Δ
Although Tnh becomes negative, the heating capacity does not actually become negative. Therefore, if the calculation is continued as it is, the average heating capacity Qn may be calculated to be smaller than the actual value, but the re-correction means (56) re-corrects to determine the defrosting operation inrush time. It can be done more accurately.

In the above embodiment, the outlet-inlet temperature Δ
At the time of obtaining Tn, the outlet temperature To of the indoor heat exchanger (6) was obtained from the internal heat exchange temperature Tc.
The value may be used as the outlet temperature To.

In the above embodiment, the medium to be heated is the conditioned air, but the present invention is not limited to this embodiment. For example, a heat exchanger for producing hot water is used. Can be similarly applied.

[0041]

As described above, according to the invention of claim 1, as the defrosting operation control device of the refrigeration system, the outlet-inlet temperature difference of the medium to be heated of the utilization side heat exchanger is periodically obtained. Then, the integrated heating capacity and the average heating capacity are calculated from the values, and a defrosting command is output when the average heating capacity drops, and the inverter frequency that gives the temperature difference corresponding to the heating capacity is used as a reference frequency. , A correction coefficient for converting the value of the outlet-inlet temperature difference into a value at a predetermined frequency is stored in advance as a function of the inverter frequency for each compressor model, and the outlet-inlet temperature difference is calculated by this correction coefficient. Since it is corrected, it is possible to correct the outlet-inlet temperature difference, which is a value deviating from the heating capacity index due to the change in the condensation temperature according to the inverter frequency, to an accurate heating capacity index. Te, it is possible to improve the timing determination accuracy of the defrosting operation inrush.

According to the invention of claim 2, in the invention of claim 1, when the corrected outlet-inlet temperature difference becomes a negative value, it is corrected again to "0". It is possible to effectively prevent the cumulative heating capacity from being calculated smaller than the actual value due to the apparent reversal of the outlet temperature and the inlet temperature that occurs under specific conditions, and thus the effect of the invention of claim 1 is obtained. It can be more significantly demonstrated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a refrigerant piping system diagram of the air conditioning apparatus according to the embodiment.

FIG. 3 is a flowchart showing the control contents for calculating the average heating capacity.

FIG. 4 is a flow chart showing the control contents for determining the defrosting entry time.

FIG. 5 is a diagram showing a quadratic regression curve of the correction coefficient with respect to the inverter frequency.

FIG. 6 is a characteristic diagram showing the effect of the present invention.

FIG. 7 is a characteristic diagram showing a time change of an outlet-inlet temperature difference.

FIG. 8 is a diagram for explaining a process of calculating an integrated heating capacity and an average heating capacity from an outlet-inlet temperature difference.

FIG. 9 is a diagram showing changes over time in average heating capacity.

[Explanation of symbols]

 1 Compressor 3 Outdoor heat exchanger (heat source side heat exchanger) 5 Electric expansion valve (pressure reducing mechanism) 6 Indoor heat exchanger (use side heat exchanger) 9 Refrigerant circuit 12 Storage device (correction type storage means) Thr Indoor suction Sensor (inlet temperature detection means) The heat exchange sensor (outlet temperature detection means) 51 Temperature difference calculation means 52 Correction means 53 Integrated heating capacity calculation means 54 Average heating capacity calculation means 55 Defrost command output means 56 Recorrection means

Claims (2)

[Claims] 1. A compressor (1) whose frequency is variably adjusted by an inverter, a heat source side heat exchanger (3), a pressure reducing mechanism (5), and a use side heat exchanger (6) are sequentially connected. In the refrigerating apparatus including the refrigerant circuit (9), the inlet temperature (T of the medium to be heated of the utilization side heat exchanger (6) (T
i) the inlet temperature detecting means (Thr), and the outlet temperature (T) of the medium to be heated of the use side heat exchanger (6).
receiving the output of the outlet temperature detecting means (The) for detecting o) and the above temperature detecting means (Thr), (The),
Outlet temperature (To) during heating operation at regular intervals
Temperature difference calculating means (51) for calculating an outlet-inlet temperature difference (ΔTn), which is a temperature difference between the inlet temperature (Ti) and the inlet temperature (Ti), and an inverter based on a predetermined frequency of the inverter that provides the temperature difference corresponding to the heating capacity. Correction for converting the outlet-inlet temperature difference (ΔTn) calculated by the temperature difference calculating means (51) into the outlet-inlet temperature difference at the predetermined frequency based on the correlation between the frequency (Hz) and the condensation temperature. Correction formula storage means (12) for storing the coefficient (XD5) as a function of the inverter frequency (Hz) for each model of the compressor (1)
According to the inverter frequency (Hz), the outlet-inlet temperature difference (ΔTn) calculated by the temperature difference calculating means (51) is stored in the correction formula storing means (12) as a correction coefficient (XD).
The correction means (52) for correction by 5) and the cumulative heating capacity (S
n) is periodically calculated based on the outlet-inlet temperature difference (ΔTnh) corrected by the correction means (53), and an integrated heating capacity calculation means (53) and a heating operation from the heating operation start time to the present time. Time (tf)
The average heating capacity (Qn) is calculated by dividing the integrated heating capacity (Sn) calculated by the integrated heating capacity calculation means (53) by the sum of the predicted defrosting operation time (tdy)
The average heating capacity calculation means (54) for calculating, and the current calculation value (Qk) of the average heating capacity (Qn) calculated by the average heating capacity calculation means (54) is calculated as the previous calculation value (Qk-1). The defrosting operation control device for a refrigerating apparatus, further comprising: a defrosting signal output means (55) that outputs a defrosting signal when the calculated value this time is small. 2. The operation control device for a refrigerating apparatus according to claim 1, wherein when the temperature difference (ΔTnh) corrected by the correction means (52) is negative, the temperature difference is corrected again to “0”. An operation control device for a refrigerating apparatus, comprising a correction means (56).