JPH0626688A - Operating controller of air conditioner - Google Patents

Abstract

PURPOSE:To surely perform defrosting and complete defrosting in a short period of time. CONSTITUTION:An internal heat exchanging temperature sensor (The) which detects the internal heat exchanging temperatures of an indoor heat exchanger 6, a defrosting commencement device 11 which outputs a defrost start signal, and a defrosting timer 12 which counts the defrosting period of time are provided. Furthermore, a temperature completion device 13 which outputs a defrost completion signal when the internal heat exchanging temperature reaches a set completion temperature during defrosting operation, and a time completion device 14 which outputs a defrosting completion signal when defrosting time comes to a set defrosting completion time are provided. In addition, a completion temperature change device 15 is provided, which outputs change signals to lower the set completion temperature of the temperature completion device 13 corresponding to the lapse of defrosting time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for an air conditioner, and more particularly to measures for controlling the termination of defrost operation.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Publication No.
As disclosed in Japanese Laid-Open Patent Publication No. -1578, there is a compressor in which a variable capacity compressor, a four-way switching valve, an outdoor heat exchanger, an electric expansion valve, and an indoor heat exchanger are sequentially connected. .
When the outdoor coil temperature of the outdoor heat exchanger reaches a predetermined temperature during the heating operation, the defrost operation is performed. Further, as shown in FIG. 5, the above-mentioned defrost operation starts with the outdoor coil temperature Te from the start A of the defrost operation.
Reaches the set end temperature of 6 ℃ to 10 ℃ (B of the temperature characteristic)
When the defrost time TD reaches the setting end time of 10 minutes (see temperature characteristic C), the defrost operation is ended and the heating operation is restarted.

[0003]

In the above-described air conditioner, the end of the defrost operation is detected depending on whether the outdoor coil temperature Te or the defrost time TD has reached a predetermined condition. The coil temperature Te of 10 ° C. and the defrost time TD of 10 minutes have conventionally been fixed values.
The setting end temperature of the outdoor coil temperature Te in the conventional example is changed and set by the outside air temperature at the start of the defrost operation.

However, as described above, the defrost time
If the TD is a long time of about 10 minutes, the outdoor coil temperature Te
Since the setting end temperature of is a fixed value, there was a problem that the defrost operation time becomes long. That is, when the defrost time TD becomes longer, the melted water is removed even if the outdoor coil temperature Te does not reach 10 ° C. Even in this state, the defrost operation is continued, the heat quantity of the refrigerant is wasted, the restart of the heating operation is delayed, and the heating operation efficiency is poor. Therefore, again, if the frost is melted at the initial stage of the defrost operation by simply lowering the setting end temperature of the outdoor coil temperature Te,
Since the outdoor coil temperature Te rises exponentially, the heating operation is restarted while the melted water remains in the coil, and there is a problem that re-frosting is likely to occur. In other words, when the amount of frost is small, the defrost operation causes the frost to melt entirely, and when the outdoor coil temperature Te reaches the set end temperature, the melted water almost flows down. On the other hand, when there is a large amount of frost, the outdoor coil temperature Te reaches the set end temperature even though all the frost has not melted and only the fin adhesion part has melted, and the defrost operation Will end. As a result, refrosting will occur.

The present invention has been made in view of the above points, and is intended to ensure defrosting and to finish the defrosting operation in a short time.

[0006]

Means for Solving the Problems In order to achieve the above object, the means taken by the present invention is to reduce the set end temperature of the condensation pressure equivalent saturation temperature when the defrost time becomes long. .

Specifically, as shown in FIG. 1, the means taken by the invention according to claim 1 is as follows. First, a compressor (1), a heat source side heat exchanger (3), and an expansion mechanism (5). And the heat exchanger on the use side (6)
It is premised on an air conditioner having a refrigerant circuit (9) in which and are connected in order.

A saturation temperature detecting means (T) for detecting the saturation temperature Te corresponding to the refrigerant pressure after the heat source side heat exchanger (3) is detected.
he), a defrost start means (11) for outputting a defrost start signal for executing the defrost operation, and a defrost count means (12) for counting the defrost time TD when the defrost start means (11) outputs the defrost start signal. And are provided. Further, when the refrigerant pressure equivalent saturation temperature Te reaches the set end temperature after the defrost start means (11) outputs the defrost start signal in response to the temperature signal of the saturation temperature detection means (The), the defrost operation is ended. Temperature end means (13) for outputting a defrost end signal to
When the defrost time counting means (12) receives the time signal and the defrost time TD reaches a set end time, a time end means (14) for outputting a defrost end signal for ending the defrost operation is provided. In addition, in response to the time signal of the defrost counting means (12), the defrost time TD
The end temperature changing means (15) for outputting a change signal to the temperature end means (13) is provided so that the temperature end means (13) lowers the set end temperature according to the progress of.

The means taken by the invention according to claim 2 is the end temperature changing means (1
In 5), when the defrost time TD reaches a preset long time, the setting end temperature is lowered in proportion to the elapse of the defrost time TD.

[0010]

With the above construction, in the invention according to claim 1,
First, in the refrigerant circuit (9), for example, the liquid refrigerant condensed and liquefied in the use side heat exchanger (6) is decompressed by the expansion mechanism (5) and then evaporated in the heat source side heat exchanger (3). Then, the evaporated gas refrigerant returns to the compressor (1) to perform heating operation. During this heating operation, when the refrigerant circuit (9) enters a predetermined state, the defrost start means (11) outputs a defrost start signal and the defrost operation is started. When the defrost start means (11) outputs a defrost start signal, the defrost count means (12) starts counting the defrost time TD. On the other hand, the saturation temperature detecting means (The) detects the refrigerant pressure equivalent saturation temperature Te after the heat source side heat exchanger (3), and is, for example, the refrigerant temperature of the use side heat exchanger (6). The heat exchange temperature Te is detected.

Thereafter, when the internal heat exchange temperature Te detected by the saturation temperature detecting means (The) reaches a predetermined set end temperature, the temperature end means (13) outputs a defrost end signal, while the defrost count means ( When 12) counts the predetermined setting end time, the time end means (14) outputs the defrost end signal. The defrost operation is terminated by the defrost end signal of either the temperature end means (13) or the time end means (14), and the heating transporter is restarted. Then, the end temperature changing means (15) receives the time signal of the defrost counting means (12), and the end temperature changing means (15),
The temperature ending means (1
A change signal for lowering the setting end temperature of 3) is output to the temperature end means (13). Specifically, in the invention according to claim 2, when the defrost time TD becomes a predetermined long time, the set end temperature is lowered in proportion to the elapse of the defrost time TD. As a result, for example, the defrost time TD is 8
When the time becomes equal to or longer than the minute, the setting end temperature decreases, and when the setting pressure reaches the refrigerant pressure equivalent saturation temperature Te, the defrost operation ends.

[0012]

Therefore, according to the invention of claim 1,
Since the set end temperature of the defrost operation is lowered according to the passage of the defrost time TD, the defrost operation time can be shortened. As a result, it is possible to prevent the defrost operation from being continued after the melted water is removed, so that it is possible to reliably prevent waste of the heat quantity of the refrigerant, and to quickly restart the heating operation. Therefore, the heating operation efficiency can be improved.

Further, according to the second aspect of the present invention, when the defrost time TD becomes a predetermined long time, the set end temperature is lowered, so that even if the frost formation amount is large, the total frost formation is prevented. Since it can be reliably melted, it is possible to reliably prevent the heating operation from being restarted while the melted water remains in the coil, and thus it is possible to prevent re-frosting.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. 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 indoor unit (B) is connected to one outdoor unit (A).

The outdoor unit (A) includes a scroll type compressor (1) whose operating frequency is variably adjusted by an inverter, and a solid line in the figure during cooling operation and a broken line in the figure during heating operation. Four-way switching valve to replace (2)
And an outdoor heat exchanger that is a heat source side heat exchanger that functions as a condenser during cooling operation and as an evaporator during heating operation.
(3) and a decompression unit (20) for decompressing the refrigerant are arranged as main devices. In addition, the indoor unit (B)
An indoor heat exchanger (6), which is a use-side heat exchanger, functions as an evaporator during cooling operation and as a condenser during heating operation. Then, the compressor (1) and the four-way switching valve
(2), the outdoor heat exchanger (3), the decompression unit (20) and the indoor heat exchanger (6) are sequentially connected by piping (8) so that heat is transferred by circulating the refrigerant. The refrigerant circuit (9) is configured.

Here, the decompression section (20) includes a bridge-shaped rectifier circuit (8r) and a pair of connection points in the rectifier circuit (8r).
A common path (8a) connected to (P, Q), and the common path (8a)
Includes a receiver (4) for storing the liquid refrigerant, an auxiliary heat exchanger (3a) for the outdoor heat exchanger (3), and an electric expansion mechanism that is an expansion mechanism that has a pressure reducing function and a flow rate adjusting function for the liquid refrigerant. Valve (5)
And are arranged in series. And the rectifier circuit (8r)
The other pair of connection points (R, S) in the
The piping (8) on the (3) side and the piping (8) on the indoor heat exchanger (6) side are connected. Further, the rectifier circuit (8r) connects the upstream connection point (P) of the common path (8a) and the connection point (S) of the outdoor heat exchanger (3) side from the external heat exchanger (3). Indoor heat exchange with the first inflow passage (8b1) equipped with the first check valve (D1) that allows only the refrigerant flow to the receiver (4), the upstream connection point (P) of the common passage (8a) The indoor heat exchanger (6) is connected to the connection point (R) on the side of the heat exchanger (6).
Second inflow path (8b2) equipped with a second check valve (D2) that allows only the refrigerant flow from the receiver to the receiver (4), the downstream connection point (Q) of the common path (8a) and the indoor heat A first check valve (D3) that connects the connection point (R) on the side of the exchanger (6) and allows only the refrigerant to flow from the electric expansion valve (5) to the indoor heat exchanger (6). Outflow channel (8
c1), the downstream side connection point (Q) of the common path (8a) and the connection point (S) on the outdoor heat exchanger (3) side, and the electric expansion valve (5) to the outdoor heat exchanger (3). The second outflow passage (8c2) provided with the fourth check valve (D4) which allows only the refrigerant flow to (4).

Further, a common path (8
Between the connection points (P, Q) in a), the capillary tube (C)
A liquid seal prevention bypass (8f) is provided
The liquid seal prevention bypass passage (8f) prevents liquid seal when the compressor (1) is stopped, while opening and closing between the upper part of the receiver (4) and the downstream side of the common passage (8a). A degassing passage (4a) equipped with a valve (SV) is connected. The degree of pressure reduction of the capillary tube (C) is set to be sufficiently higher than that of the electric expansion valve (5), and the function of adjusting the refrigerant flow rate by the electric expansion valve (5) during normal operation is maintained well. It is designed to be profitable. Further, (F1 to F5) 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, (Thd) is a discharge pipe sensor which is arranged in the discharge pipe of the compressor (1) and detects the discharge pipe temperature Td, (Tha) Is
An outdoor suction sensor that is located at the air suction port of the outdoor unit (A) and detects the suction air temperature Ta, which is the outside air temperature, (Thc)
Is located in the outdoor heat exchanger (3) and detects the external heat exchange temperature Tc, which is the condensation temperature during the cooling operation and the evaporation temperature during the heating operation, and (Thr) is the indoor unit.
The indoor suction sensor, which is located at the air inlet of (B) and detects the intake air temperature Tr that is the room temperature, (The) is located at the indoor heat exchanger (6), and becomes the evaporation temperature during cooling operation. At the time of heating operation, the condensing temperature is reached, and at the time of defrost operation, the internal heat exchange sensor (saturation temperature detection means) that detects the internal heat exchange temperature Te (saturation temperature Te equivalent to the refrigerant pressure) indicating the frosted state High pressure pressure switch, which detects the refrigerant pressure and outputs a high voltage signal when the high pressure refrigerant pressure is excessively increased to turn on, (LPS) detects the low pressure refrigerant pressure,
It is a low pressure switch that is turned on when the low pressure refrigerant pressure drops excessively and outputs a low pressure signal. The output signals of the sensors (Thd, ~, The) and the switches (HPS, LPS) are input to the controller (10), and the controller (10) performs air conditioning operation based on the input signal. Is configured to control.

In the above-mentioned refrigerant circuit (9), during the cooling operation, the liquid refrigerant condensed and liquefied in the outdoor heat exchanger (3) flows from the first inflow passage (8b1), and the first check valve (D1) ) And then stored in the receiver (4), decompressed by the electric expansion valve (5), then evaporated in the indoor heat exchanger (6) through the first outflow path (8c1) and returned to the compressor (1). While circulating, during heating operation,
Liquid refrigerant condensed and liquefied in the indoor heat exchanger (6) flows in from the second inflow path (8b2), passes through the second check valve (D2), and then is received by the receiver.
After being stored in (4) and decompressed by the electric expansion valve (5), the second
Compressor by evaporating in the outdoor heat exchanger (3) via the outflow passage (8c2)
The cycle returns to (1).

On the other hand, the controller (10) is provided with a defrost starting means (11) and, as a feature of the present invention, a defrost timer (12) and a temperature ending means (13) for controlling the end of the defrost operation. A time end means (14) and an end temperature changing means (15) are provided. Then, the controller (10) divides the operating frequency of the inverter into 20 steps N from zero to the maximum frequency, sets each frequency step N based on the discharge pipe temperature Td, and sets the capacity of the compressor (1). Is configured to control. Further, the defrost start means (11) is configured to output a defrost start signal when the refrigerant circuit (9) enters a predetermined state, for example, integrated heating from the start of heating operation after the end of defrost operation. The average heating capacity is calculated by dividing the integrated heating capacity by the addition time of the heating operation time after the end of the defrost operation and the preset expected defrost operation time while memorizing the capacity, and the average heating capacity is the average of the previous time. When it becomes smaller than the heating capacity, the defrost start signal is output. Then, in response to this defrost start signal, the controller (10) sets the refrigerant circuit (9) to the cooling cycle of the reverse cycle and executes the defrost operation.

The defrost timer (12) constitutes defrost counting means for counting the defrost time TD when the defrost start means (11) outputs a defrost start signal. The temperature ending means (13) is an internal heat exchange sensor.
In response to the (The) temperature signal, the defrost starting means (1
When the internal heat exchange temperature Te reaches the set end temperature Tx, for example, 10 ° C. after 1) outputs the defrost start signal, the defrost end signal for ending the defrost operation is output. The time ending means (14) receives the time signal from the defrost timer (12) and
When the TD reaches the set end time, for example, when the set end time reaches 10 minutes, a defrost end signal for ending the defrost operation is output. Then, the controller (10) ends the defrost operation and restarts the heating operation by the defrost end signal output from the temperature end means (13) or the time end means (14). The end temperature changing means (15) receives the time signal of the defrost timer (12), and the temperature end means (13) lowers the set end temperature Tx in response to the elapse of the defrost time TD. It is configured to output a change signal to the termination means (13). Specifically, the end temperature changing means (15) is shown in FIG.
As shown in, when the defrost time TD becomes a long time of 8 minutes, the set end temperature Tx is decreased in proportion to the elapse of the defrost time TD.

Next, the end control operation of the defrost operation of the compressor (1) will be described based on the control flow of FIG. First, in step ST1, the defrost flag
Whether the FD is set or not is determined. If the defrost flag FD is not set, the heating operation is being performed, and therefore the process directly returns. During this heating operation, when the defrost start means (11) outputs a defrost start signal, that is, when the average heating capacity reaches a predetermined value, the defrost flag FD is set and the operation cycle is changed to the cooling cycle to defrost. The operation is started (see FIG. 4D), the determination in step ST1 is YES, and the process proceeds to step ST2. When the defrost start means (11) outputs a defrost start signal, the defrost timer (12) outputs the defrost time.
It will start counting TD.

Subsequently, in step ST2, it is judged whether or not the discharge pipe temperature Td of the compressor (1) is higher than 120 ° C., and the step ST is continued until the discharge pipe temperature Td reaches 120 ° C.
The determination of 2 is NO, and the process proceeds to step ST3. In this step ST3, the temperature terminating means (13) receives the temperature signal from the internal heat exchange sensor (The) and judges whether the internal heat exchange temperature Te has become equal to or higher than the set end temperature Tx. The determination in step ST3 becomes NO until the temperature Te reaches the setting end temperature Tx, and the process proceeds to step ST4 without outputting the defrost end signal. That is, the setting end temperature Tx has an initial value set to 10 ° C., and the temperature end means (13) determines whether the internal heat exchange temperature Te has become 10 ° C. or higher. In this step ST4, the time end means (14) receives the time signal of the defrost timer (12), and the time end means (14) determines whether the defrost time TD has reached the predetermined setting end time of 10 minutes. Whether the defrost time TD reaches 10 minutes, the determination in step ST4 becomes NO, and the step ST4 is performed without outputting the defrost end signal.
I will move to 5. Next, in this step ST5, the end temperature changing means (15) causes the defrost timer (1
Upon receiving the time signal of 2), it is determined whether or not the defrost time TD has reached 8 minutes, and the determination in step ST5 becomes NO until the defrost time TD reaches 8 minutes, and the temperature termination means
It returns without changing the setting end temperature Tx of (13). That is, the defrost operation is performed until the internal heat exchange temperature Te reaches the set end temperature Tx or the defrost time TD reaches the set end time, while the defrost time is maintained at 10 ° C until the defrost time TD reaches 8 minutes. It

Thereafter, when the internal heat exchange temperature Te reaches 10 ° C. which is the set end temperature Tx during the continuation of the defrosting operation (see temperature characteristic E in FIG. 4), the determination in step ST3 is YES, and the step Moving to ST6, the temperature end means (13) outputs a defrost end signal and returns. Then, the defrost operation is ended by the defrost end signal and the heating operation is restarted. When the defrost time TD reaches 10 minutes, which is the set end time, without increasing the internal heat exchange temperature Te during the continuation of the defrost operation (see temperature characteristic G in FIG. 4), the above steps are performed.
The determination in ST4 is YES, and the process moves to step ST6 above.
The time end means (14) outputs a defrost end signal and returns. Then, the defrost operation is ended by the defrost end signal, and the controller (10) restarts the heating operation. Further, if the discharge pipe temperature Td rises to 120 ° C. or higher during the continuation of the defrost operation, the determination in step ST2 is YES, and the step ST
The process moves to 6 and outputs the defrost end signal and returns. Then, the defrost operation is ended by the defrost end signal, and the control is shifted to the normal control.

On the other hand, when the defrosting operation is continued without the internal heat exchange temperature Te rising during the continuation of the defrosting operation and the defrosting time TD reaches 8 minutes, the determination in step ST5 becomes YES and step ST7 Then, the end temperature changing means (15) outputs a change signal to the temperature end means (13), and as shown in FIG. 4X, the temperature end means (13).
The setting end temperature Tx is decreased in proportion to the elapse of the defrost time TD, and the process returns. Then, after the defrost time TD has passed 8 minutes, the internal heat exchange temperature Te rises, and when the internal heat exchange temperature Te reaches the changed set end temperature Tx (see temperature characteristic F in FIG. 4), If the determination in step ST3 is YES, the process proceeds to step ST6, in which the temperature end means (13) outputs a defrost end signal and returns. Then, the defrost operation is ended by the defrost end signal and the heating operation is restarted.

Therefore, according to the present embodiment, the set end temperature Tx of the defrost operation is corresponding to the elapse of the defrost time TD.
Therefore, the defrost operation time can be shortened. As a result, it is possible to prevent the defrost operation from being continued after the melted water is removed, so that it is possible to reliably prevent waste of the heat quantity of the refrigerant, and to quickly restart the heating operation. Therefore, the heating operation efficiency can be improved. Further, when the defrost time TD reaches a predetermined long time (8 minutes), the setting end temperature Tx is lowered,
Even if the amount of frost is large, it is possible to reliably melt all frost, so it is possible to reliably prevent the heating operation from restarting while the melted water remains in the coil. Can be prevented.

In each of the embodiments, the separate type air conditioner has been described, but it goes without saying that the present invention can be applied to various air conditioners. Further, the change of the set end temperature Tx in the end temperature changing means (15) is not limited to 8 minutes of the defrost time TD, but may be changed corresponding to the defrost time TD.
In addition, the temperature detected by the saturation temperature detection means is the internal heat exchange sensor (T
he) is not limited to the internal heat exchange temperature Te, but may be the refrigerant pressure equivalent saturation temperature Te after the outdoor heat exchanger (3).

[Brief description of drawings]

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

FIG. 2 is a refrigerant circuit diagram showing a refrigerant piping system of the air conditioner.

FIG. 3 is a control flow chart showing control of defrost operation.

FIG. 4 is a characteristic diagram of an internal heat exchange temperature Te during defrost operation.

FIG. 5: Internal heat exchange temperature Te during conventional defrost operation
FIG.

[Explanation of symbols]

 1 Compressor 3 Outdoor Heat Exchanger (Heat Source Side Heat Exchanger) 5 Electric Expansion Valve (Expansion Mechanism) 6 Indoor Heat Exchanger (Use Side Heat Exchanger) 9 Refrigerant Circuit 10 Controller 11 Defrost Start Means 12 Defrost Timer (Defrost Count) Means) 13 temperature end means 14 hour end means 15 end temperature change means The internal heat exchange sensor (saturation temperature detection means)

Claims (2)

[Claims] 1. A compressor (1), a heat source side heat exchanger (3),
In an air conditioner equipped with a refrigerant circuit (9) in which an expansion mechanism (5) and a use side heat exchanger (6) are connected in sequence, a refrigerant pressure after the heat source side heat exchanger (3) Saturation temperature
A saturation temperature detecting means (The) for detecting Te, a defrost start means (11) for outputting a defrost start signal for executing a defrost operation, and a defrost time TD when the defrost start means (11) outputs a defrost start signal. After receiving the temperature signal of the defrost counting means (12) for counting the defrosting counting means (12) and the saturation temperature detecting means (The), the defrosting starting means (11) outputs the defrosting start signal, and then the saturation temperature Te equivalent to the refrigerant pressure is set. When the temperature reaches the temperature end means (13) for outputting the defrost end signal for ending the defrost operation and the time signal of the defrost counting means (12), when the defrost time TD reaches the set end time, the defrost operation is started. The time ending means (14) for outputting the defrost end signal for ending and the time signal for the defrost counting means (12) are received, and the defrost time TD is passed. Corresponding to the above, the temperature end means (13) is provided with end temperature change means (15) for outputting a change signal to the temperature end means (13) so as to lower the set end temperature. Operation control device for air conditioner. 2. The operation control device for an air conditioner according to claim 1, wherein the end temperature changing means (15) is proportional to the progress of the defrost time TD when the defrost time TD reaches a preset long time. An operation control device for an air conditioner, wherein the operation control device is configured to lower the setting end temperature.