JPH09222271A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator which can be accurately finished for the defrosting operation of a positive cycle based on the temperature rise of an outdoor heat exchanger. SOLUTION: The defrosting operation control unit 11 of a controller 10 controls the defrosting operation for defrosting an outdoor heat exchanger 3 without switching a heating operation cycle. The temperature change discriminator 12 of the controller 10 discriminates whether the temperature change per unit time of the exchanger 3 is a first predetermined temperature or lower or not after the defrosting operation is started. When the discriminator 12 discriminates that the temperature change per unit time of the exchanger 3 is the first temperature or lower, a reference temperature setter 13 sets the temperature of the exchanger 3 to a reference temperature. When a temperature difference discriminator 14 discriminates that the difference between the reference temperature and the temperature of the exchanger 3 is a second predetermined temperature or more, an end instructing unit 15 outputs a command signal for ending the defrosting operation to the controller 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system for performing a normal cycle defrost operation.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, an air conditioner has a compressor 21, a four-way valve 22, and an outdoor heat exchanger 23.
An expansion valve 24, a refrigerant circuit in which an indoor heat exchanger 25 and an accumulator 26 are connected in an annular shape, and after switching the four-way valve 22 to a switching position indicated by a dotted line, the compressor 21
To start heating operation. Then, when frost forms on the outdoor heat exchanger 23 during the heating operation, the indoor fan is turned off without switching the four-way valve 22 at the switching position indicated by the dotted line, and the outdoor heat exchanger 23 is removed by the normal cycle defrost operation. Defrost.

As shown in FIG. 7, another air conditioner includes a compressor 31, a four-way valve 32, an outdoor heat exchanger 33, an expansion valve 34, an indoor heat exchanger 35 and an accumulator. 36 is provided with a refrigerant circuit connected in an annular shape, and a pipe between the outdoor heat exchanger 33 and the expansion valve 34 and the discharge side of the compressor 1 are connected by a bypass passage 37, and the bypass passage 37 is connected to the bypass passage 37. An on-off valve 38 is provided. In this air conditioner, the four-way valve 22 is switched to the switching position indicated by the solid line to open and close the open / close valve 3
The compressor 31 is driven in a state where 8 is closed to perform heating operation. When frost is formed on the outdoor heat exchanger 33 during the heating operation, the four-way valve 32 is left in the switching position indicated by the solid line and the on-off valve 3
8 is opened, and the defrosting operation of the normal cycle continues the heating operation, and the outdoor heat exchanger 33 is defrosted by the hot gas that has passed through the bypass passage 37.

[0004]

However, in order to reduce the cost, the air conditioner shown in FIG. 6 which performs the defrost operation in the normal cycle without using the bypass passage and the on-off valve,
The hot gas discharged from the compressor 21 is the indoor heat exchanger 25.
To the outdoor heat exchanger 23 via the bypass path,
The temperature of the outdoor heat exchanger 23 does not rise as much as that of the air conditioner using the on-off valve, and therefore the defrost operation is ensured at the end of defrosting of the outdoor heat exchanger 23 based on the temperature rise of the outdoor heat exchanger 23. There is a problem that it is difficult to finish.

Therefore, an object of the present invention is to provide a refrigerating apparatus which can accurately terminate the defrost operation of the normal cycle based on the temperature rise of the outdoor heat exchanger.

[0006]

In order to achieve the above object, a refrigerating apparatus according to claim 1 is provided with a refrigerant circuit in which a compressor, an evaporator, an expansion means and a condenser are annularly connected, and the evaporator is provided. In a refrigerating apparatus that performs a positive cycle defrost operation for defrosting, the temperature of the evaporator when the temperature change per unit time of the evaporator is equal to or lower than a first predetermined temperature after the defrost operation is started is a reference temperature. And then the temperature difference between the evaporator temperature and the reference temperature is the second
It is characterized in that the above-mentioned defrosting operation is terminated when the temperature exceeds a predetermined temperature.

According to the refrigerating apparatus of the first aspect, when the evaporator is frosted during the heating operation, if the defrost operation of the normal cycle is performed without switching the heating operation cycle, the temperature of the evaporator gradually increases from below the freezing point. When the frost begins to melt, the temperature rise stops and the temperature becomes almost constant until all the frost melts. Therefore, when the temperature change of the evaporator per unit time is equal to or lower than the first predetermined temperature, the temperature of the evaporator is set as the reference temperature. Then, after the frost of the evaporator is melted, the temperature of the evaporator rises again, and when the temperature difference between the evaporator temperature and the reference temperature becomes the second predetermined temperature or more, the evaporator is completely defrosted. As a matter of fact, the defrost operation is ended. Therefore, the defrosting operation is terminated while the defrosting of the evaporator is insufficient, or the defrosting operation is not continued despite the defrosting being completed,
Since the defrost operation can be ended accurately and the heating operation can be quickly returned to, the comfort in the room can be improved.

In the refrigerating apparatus of the second aspect, the refrigerant circuit in which the compressor, the evaporator, the expansion means and the condenser are annularly connected, and the defrost operation for controlling the positive cycle defrost operation for defrosting the evaporator. In a refrigerating apparatus having an operation control means, after starting the defrosting operation, temperature change determination means for determining whether or not a temperature change per unit time of the evaporator is a first predetermined temperature or less, and the temperature change. When the determining means determines that the temperature change of the evaporator per unit time is equal to or lower than the first predetermined temperature, the reference temperature setting means uses the temperature of the evaporator at that time as a reference temperature, and after setting the reference temperature. Temperature difference determining means for determining whether the temperature difference between the evaporator temperature and the reference temperature is equal to or more than a second predetermined temperature, and the temperature difference determining means determines the temperature between the reference temperature and the evaporator temperature. difference If it is determined that it is the second predetermined temperature or higher, and a command signal to end said defrost operation is characterized in that a defrost operation end command means for outputting to the defrosting operation control means.

According to the refrigerating apparatus of the second aspect, when frost is formed on the evaporator during the heating operation, if the defrost operation of the forward cycle is performed by the defrost operation control means without switching the heating operation cycle, the evaporator is cooled. The temperature gradually rises from below freezing, and when the frost begins to thaw, the temperature rise of the evaporator stops, and the temperature becomes almost constant until the frost thaws. Therefore, when the temperature change determining means determines that the temperature change of the evaporator per unit time is less than or equal to the first predetermined temperature, the reference temperature setting means sets the temperature of the evaporator at this time as the reference temperature. Then, after the frost of the evaporator is melted, the temperature of the evaporator rises again, and the temperature difference determining means determines whether the temperature difference between the evaporator temperature and the reference temperature is equal to or higher than the second predetermined temperature. If it is determined that the temperature difference is equal to or higher than the second predetermined temperature, it is determined that the evaporator has been completely defrosted, and the defrost operation end command means sends a command signal to the defrost operation control means to end the defrost operation. Output. Then, in response to the command signal, the defrost operation control means ends the defrost operation. Therefore, the defrosting of the evaporator is not sufficient or the defrosting operation is not continued even though the defrosting has been completed, and the defrosting operation can be accurately ended and the heating is quickly performed. Since it returns to driving, it is possible to improve indoor comfort.

A refrigerating apparatus according to a third aspect is the refrigerating apparatus according to the first aspect, further comprising a timer for measuring a fixed time from the start of the defrost operation, and the temperature change determining means measures the time of the timer. After completion of the above, it is characterized in that it is judged whether or not the temperature change per unit time of the evaporator is below the first predetermined temperature.

According to the refrigerating apparatus of the third aspect, if it takes time from the start of the defrost operation until the temperature of the evaporator rises due to frost formation on the evaporator, the reference temperature setting means erroneously causes The reference temperature may be set below the freezing point before the temperature of the evaporator rises. Therefore, based on the time count of the timer, the temperature change per unit time of the evaporator by the temperature change determining means is the first predetermined time from the start of the defrost operation until the temperature of the evaporator starts to rise.
The reference temperature is not set by the reference temperature setting means by not determining whether or not the temperature is equal to or lower than the predetermined temperature.
Therefore, the defrost operation is not stopped by mistake.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The refrigerating apparatus of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a circuit diagram of an air conditioner as a refrigerating apparatus according to an embodiment of the present invention, in which 1 is a compressor, 2 is a four-way valve connected to the discharge side of the compressor 1, and 3 is a three-way valve. Is an outdoor heat exchanger whose one end is connected to the four-way valve 2, 4 is an expansion valve whose one end is connected to the other end of the outdoor heat exchanger 3, and 5 is one end which is connected to the other end of the expansion valve 4. The indoor heat exchanger 6 is an accumulator connected to the other end of the indoor heat exchanger 5 via a four-way valve 2. The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, the indoor heat exchanger 5, and the accumulator 6 constitute an annular refrigerant circuit.

Further, the air conditioner receives a temperature sensor 7 for detecting the temperature of the outdoor heat exchanger 3 and a signal representing the temperature of the outdoor heat exchanger 3 from the temperature sensor 7, and receives the signal from the compressor. 1 and the control device 10 for controlling the operation and the like. The control device 10 includes a microcomputer, an input / output circuit, and the like, and is a defrost operation control unit 11 as a defrost operation control unit that controls the defrost operation.
And a temperature change determination unit 12 as a temperature change determination unit that determines a temperature change of the outdoor heat exchanger 3, and a reference temperature setting unit that sets a reference temperature based on the temperature change of the outdoor heat exchanger 3. The reference temperature setting unit 13, the temperature difference determination unit 14 as a temperature difference determination unit that determines the temperature difference between the temperature of the outdoor heat exchanger 3 and the reference temperature, and the defrost operation control unit 11 to terminate the defrost operation. It has an end instruction unit 15 as a defrost operation end instruction means for giving an instruction, and a timer 16 for measuring various times in the defrost operation.

In the air conditioner having the above configuration, when performing the heating operation, the four-way valve 2 is switched to the switching position indicated by the solid line,
The compressor 1 is started. The high-temperature, high-pressure refrigerant discharged from the compressor 1 flows through the four-way valve 2, the indoor heat exchanger 5 functioning as a condenser, and the expansion valve 4, and the refrigerant decompressed by the expansion valve 4 evaporates. The heat flows through the outdoor heat exchanger 3 and the four-way valve 2 functioning as a heat exchanger, and returns to the accumulator 6 from the four-way valve 2. In this way, the outdoor heat exchanger 3 is provided by the heating-side refrigeration cycle in which the refrigerant is circulated in the direction of the solid line arrow in FIG.
The heat is absorbed from the outside air as a heat source, and the heat is released by the indoor heat exchanger 5 to heat the room.

In the heating operation, when frost is formed on the outdoor heat exchanger 3 as the evaporator, the indoor fan is turned off and the compressor 1 is operated in the heating side refrigeration cycle without switching the four-way valve 2. And the defrosting operation of the normal cycle for defrosting the outdoor heat exchanger 3 is performed.

2 and 3 are flow charts for explaining the operation of the controller 10 during the defrost operation.

The processing of the control device 10 will be described below with reference to the flowcharts of FIGS. It should be noted that the temperature of the outdoor heat exchanger 3 input from the temperature sensor 7 at each sample period t _{K is} set to T _K (n) (where n = 0, 1, 2, ...).

First, in step S1, the defrost operation is started. Next, in step S2, n is initialized to 0. Next, after starting the timer 16, step S
Proceed to 4.

[0020] Then, time measurement t of the timer 16, it is determined whether or not a predetermined time t _D above in step S4, when timing t is a predetermined time or more t _D, the process proceeds to step S5, timing t
When is less than the predetermined time t _D, repeats step S4 until timing t is equal to or greater than the certain time t _D.

Next, in step S5, the temperature T _K (n) of the outdoor heat exchanger 3 detected by the temperature sensor 7 is input. Next, in step S6, the time t of the timer 16 is (t _D +
It is determined whether or not (n + 1) t _K ) or more, and the time t is (t _D + (n + 1)
If it is determined that t _K) or more, the process proceeds to step S7, if it is determined timing t is less than _{(t D + (n + 1} ) t K), timing t is (t _D
Step S6 is repeated until + (n + 1) t _K ) or more.

Next, after incrementing n by 1 in step S7,
Step S8, outdoor detected by the temperature sensor 7
Temperature T of heat exchanger 3_KEnter (n). Next, step S
9 the temperature change determination unit 12 determines the current temperature of the outdoor heat exchanger 3.
Degree T_K(n) and previous temperature T_KTemperature change with (n-1) (T_K(n) -T_K
(n-1)) is the first predetermined temperature ΔT_KDetermine whether it is
Degree change (T_K(n) -T_K(n-1)) is the first predetermined temperature ΔT_KAnd
When the determination is made, the process proceeds to step S10 shown in FIG.
Degree change (T_K(n) -T_K(n-1)) is the first predetermined temperature ΔT _KBeyond
If so, the process proceeds to step S20. And
In step S20, the time t of the timer 16 is the maximum defrost time
t_FIt is determined whether or not the above, and the time t is the maximum defrost time.
Interval t_FIf it is determined that it is less than 1, the process returns to step S6.
However, the time t is the maximum defrost time t_FDetermined to be above
Then, the process proceeds to step S16 in FIG. 3 and the defrost operation is performed.
End the roll.

Next, referring to FIG. 3, in step S10,
Temperature change by the reference temperature setting unit 13 (T _K (n) -T _K (n-1))
The temperature T _K (n) of the outdoor heat exchanger 3 when it is determined that is equal to or lower than the first predetermined temperature ΔT _K is set as the reference temperature T _A. Then, the process proceeds to step S11, and the time t of the timer 16 is (t <sub>D
+ (N + 1) t K</sub> ) or whether to determine a timing t is (t _D + (n +
1) t _K ) or more, the process proceeds to step S12,
When it is determined that the time t is less than (t _D + (n + 1) t _K ), the process returns to step S11, and step S11 is repeated until the time t becomes (t _D + (n + 1) t _K ) or more.

Next, after incrementing n by 1 in step S12,
In step S13, the temperature T _K (n) of the outdoor heat exchanger 3 detected by the temperature sensor 7 is input. Next, in step S14, the temperature difference determination unit 14 determines the second temperature difference (T _A −T _K (n)) between the temperature T _K (n) of the outdoor heat exchanger 3 and the reference temperature T _A.
To determine whether a predetermined temperature △ T _R above, the temperature difference (T _A
If it is determined that −T _K (n)) is equal to or higher than the second predetermined temperature ΔT _R , the process proceeds to step S16, while if it is determined that the temperature difference (T _A −T _K (n)) is less than the second predetermined temperature ΔT _R. , And proceeds to step S15. Then, time measurement t of the timer 16 to determine whether or not the maximum defrosting time t _F or more at step S15, the timing t is determined as the maximum defrosting time t _F above, steps S
On the other hand, when it is determined in step S15 that the time t is less than the maximum defrost time t _F while proceeding to step 16, the process returns to step S11 to continue the defrost operation. Then, step S1
At 6, the end command unit 15 outputs a command signal for ending the operation, and the defrost operation control unit 11 ends the defrost operation by the command signal.

FIG. 4 shows a timing chart when the defrost operation is performed from the heating operation state. When the defrost signal from the defrost operation control unit 11 of the control device 10 turns on, the operating frequency of the compressor 1 is defrosted. At the same time, the indoor fan (not shown) is turned off and the outdoor fan (not shown) is kept on. Then, the timer 16 is started at the same time when the defrost signal is turned on. Then, based on the timing of the timer 16, a fixed time t has passed since the defrost signal was turned on.
_{After the} lapse of _D, the operating frequency of the compressor 1 is changed to determine the temperature change of the outdoor heat exchanger 3 at every sampling cycle t _K. If the reference temperature T _A cannot be obtained due to the temperature change at each sampling cycle t _K , or if the temperature difference from the reference temperature T _A does not exceed ΔT _R , the maximum after the defrost operation is started. When the defrost time t _F has elapsed, the defrost operation is automatically ended and the heating operation is resumed.

As shown in FIG. 5, after the temperature T _K of the outdoor heat exchanger 3 becomes the freezing frosted state, when starting the defrosting operation, the temperature T _K of the outdoor heat exchanger 3 is gradually increased After a certain time t _{D has} passed, the outdoor heat exchanger 3
Frost begins to thaw. The temperature of the outdoor heat exchanger 3 becomes substantially constant until all the frost in the outdoor heat exchanger 3 is melted, and after the frost is melted, the temperature T _K rises again. Therefore, the substantially constant temperature when the frost of the outdoor heat exchanger 3 is melted is set as the reference temperature T _A, and the temperature rise of the outdoor heat exchanger 3 after the frost is melted is monitored to determine the reference temperature T _{A. When} the temperature T _K of the outdoor heat exchanger 3 becomes higher than the second predetermined temperature ΔT _R than A, the defrost operation is ended.

Thus, during the heating operation, the outdoor heat exchanger 3
When frost is formed on the outdoor heat exchanger, defrosting operation in a normal cycle is performed without switching the heating operation cycle, the temperature T _K of the outdoor heat exchanger 3 gradually rises from below freezing, and when the frost begins to melt, the outdoor heat exchanger The temperature rise of No. 3 stops and the temperature becomes substantially constant until the frost melts. When the temperature T _K of the outdoor heat exchanger 3 at this time is set to the reference temperature T _A, and the temperature T _K of the outdoor heat exchanger 3 rises again after the frost has melted, the temperature of the outdoor heat exchanger T _K. Is the second difference between the temperature and the reference temperature T _A
When the temperature is equal to or higher than the predetermined temperature ΔT _{R, it is} determined that the outdoor heat exchanger 3 is completely defrosted, and the defrost operation is ended. Therefore, the defrosting of the outdoor heat exchanger 3 is not sufficient or the defrosting operation is not continued despite the defrosting being completed, and the defrosting of the outdoor heat exchanger 3 is surely performed. After the operation, the defrost operation can be accurately ended, and the heating operation can be quickly returned to, so that the indoor comfort can be improved.

Further, the outdoor heat exchanger 3 is provided with a timer 16 for measuring a constant time t _D from the start of the defrost operation, and the temperature T _K of the outdoor heat exchanger 3 is frosted from the start of the defrost operation. If it takes a long time to rise, the reference temperature setting unit 13 prevents the reference temperature T _A from being erroneously set to the reference temperature T _A before the temperature of the outdoor heat exchanger 3 rises. Temperature of heat exchanger 3 T _K
Temperature change determination unit 1 for a fixed time t _D until the temperature starts to rise
The reference temperature T _A is not set by the reference temperature setting unit 13 without performing the determination according to 2. Therefore, the reference temperature T _A is not erroneously set by the reference temperature setting unit 13 below the freezing point before the temperature of the outdoor heat exchanger 3 rises by mistake, and the defrost operation is not stopped by mistake.

Although the present invention has been described with reference to the air conditioner as the refrigerating apparatus in the above embodiment, it goes without saying that the refrigerating apparatus is not limited to the air conditioner.

Further, in the above-described embodiment, after the defrosting operation is started, the timer 16 measures the predetermined time t _D, and then the temperature change determining section 12 as the temperature change determining means makes the determination. It is not necessary to have a timer for measuring a fixed time period from the start of the defrost operation depending on the capacity of the above.

[0031]

As is apparent from the above, the refrigerating apparatus of the invention of claim 1 is provided with a refrigerant circuit in which a compressor, a condenser, an expansion means and an evaporator are connected in an annular shape, and the evaporator is removed. In a refrigeration system that performs a defrosting operation in a positive cycle of frosting, after starting the defrosting operation, the temperature of the evaporator when the temperature change per unit time of the evaporator is equal to or lower than a first predetermined temperature is set as a reference temperature. After that, when the temperature difference between the evaporator temperature and the reference temperature becomes equal to or higher than the second predetermined temperature, the defrost operation is finished.

Therefore, according to the refrigerating apparatus of the invention of claim 1, when the evaporator is frosted during the heating operation, the defrost operation of the normal cycle is performed to increase the temperature of the evaporator,
The temperature of the evaporator is kept substantially constant until the frost is completely melted until it is completely melted, and when the temperature change of the evaporator per unit time becomes equal to or lower than the first predetermined temperature, the temperature of the evaporator at this time becomes the reference temperature. To do. Then, after the frost of the evaporator is completely melted, the temperature of the evaporator rises again, and when the temperature difference between the evaporator temperature and the reference temperature becomes equal to or higher than the second predetermined temperature, the evaporator is completely removed. The defrost operation is terminated as if it had been frosted. Therefore, the defrosting operation is terminated while the defrosting of the evaporator is insufficient, or the defrosting operation is not continued despite the defrosting being completed,
The defrost operation can be accurately ended, the heating operation can be quickly returned to, and the indoor comfort can be improved.

Further, in the refrigerating apparatus of the invention of claim 2, the refrigerant circuit in which the compressor, the condenser, the expansion means and the evaporator are connected in an annular shape, and the defrost operation of the positive cycle for defrosting the evaporator are controlled. In the refrigerating apparatus having the defrost operation control means, when the temperature change determination means determines that the temperature change per unit time of the evaporator is not more than the first predetermined temperature after starting the defrost operation, the reference temperature setting means When the temperature of the evaporator at that time is set as the reference temperature and the temperature difference determining means determines that the temperature difference between the evaporator temperature and the reference temperature is the second predetermined temperature or more, the defrost operation end command is issued. The means outputs a command signal for ending the defrost operation to the defrost operation control means.

Therefore, according to the refrigerating apparatus of the second aspect of the invention, when the evaporator is frosted during the heating operation, the defrost operation control means performs the defrost operation in the positive cycle to increase the temperature of the evaporator. The temperature of the evaporator is kept substantially constant until the frost is completely melted until it is completely melted, and when the temperature change determination means determines that the temperature change per unit time of the evaporator is less than or equal to the predetermined temperature, the reference temperature is reached. The setting means sets the temperature of the evaporator at that time as the reference temperature.
Then, after the frost of the evaporator is melted, when the temperature of the evaporator rises again, the temperature difference determination means determines whether or not the temperature difference between the temperature of the evaporator and the reference temperature is equal to or higher than a predetermined temperature. Then, when it is determined that the temperature difference is equal to or higher than the predetermined temperature,
Assuming that the evaporator has been completely defrosted, the defrost operation end command means outputs a command signal for ending the defrost operation to the defrost operation control means, and the defrost operation control means ends the defrost operation. Therefore, the defrosting of the evaporator is not sufficient or the defrosting operation is not continued even though the defrosting is completed, and the defrosting operation can be accurately ended, and the heating operation can be performed. It is possible to quickly return to improve the comfort in the room.

A refrigerating apparatus according to a third aspect of the present invention is the refrigerating apparatus according to the first aspect, further comprising a timer for measuring a fixed time from the start of the defrost operation, and the temperature change determining means is the timer. After the end of the time measurement, it is determined whether the temperature change of the evaporator per unit time is less than or equal to a predetermined temperature.Therefore, a predetermined constant time from the start of the defrost operation until the temperature of the evaporator starts to rise, The temperature change determination means does not determine whether or not the temperature change of the evaporator per unit time is less than or equal to a predetermined temperature, and the reference temperature setting means does not set the reference temperature. Therefore, it is possible to prevent the reference temperature setting means from accidentally setting the reference temperature below the freezing point before the temperature of the evaporator rises because it takes time from the start of the defrost operation until the temperature of the evaporator rises. it can. Therefore, the defrost operation is not stopped by mistake.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an air conditioner as a refrigerating apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the control device for the air conditioner.

FIG. 3 is a flowchart illustrating an operation of the control device of the air conditioner.

FIG. 4 is a timing chart during defrost operation of the air conditioner.

FIG. 5 is a view showing a temperature change of the outdoor heat exchanger during the defrost operation of the air conditioner.

FIG. 6 is a circuit diagram of a conventional air conditioner.

FIG. 7 is a circuit diagram of another conventional air conditioner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... 4-way valve, 3 ... Outdoor heat exchanger, 4 ... Expansion valve, 5 ... Indoor heat exchanger, 6 ... Accumulator, 7 ... Outdoor heat exchanger temperature sensor, 10 ... Control device, 11 ... Defrost operation control unit, 12 ... Temperature change determination unit, 13 ... Reference temperature setting unit, 14 ... Temperature difference determination unit, 15 ... End command unit, 16
... timer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Suzuki 2 at 1000 Otani Okamoto-cho, Kusatsu-shi, Shiga Daiga Industry Co., Ltd. Shiga Works (72) Inventor Chiatsu Minada 1000 Otani, Okamoto-cho, Kusatsu-shi, Shiga No. 2 Inside Daikin Industries, Ltd. Shiga Works

Claims (3)

[Claims] 1. A refrigerant circuit in which a compressor (1), an evaporator (3), an expansion means (4) and a condenser (5) are annularly connected,
In a refrigerating apparatus for performing a normal cycle defrosting operation for defrosting the evaporator (3), a temperature change per unit time of the evaporator (3) after the defrosting operation is started is a first predetermined temperature (ΔT). _K) the following the evaporator when the (3) temperature (T _K) of the set as a reference temperature (T _a), then the temperature of the evaporator (3) (T _K) and the reference temperature (T _a ) the temperature difference between the (T _K -T _a) the second predetermined temperature (△ T _R)
A refrigerating apparatus characterized by terminating the above-mentioned defrost operation when the above is reached. 2. A refrigerant circuit in which a compressor (1), an evaporator (3), an expansion means (4) and a condenser (5) are annularly connected, and a positive cycle for defrosting the evaporator (3). In the refrigerating apparatus provided with the defrost operation control means (11) for controlling the defrost operation, the temperature change per unit time of the evaporator (3) after the defrost operation is started is the first predetermined temperature (ΔT). _K ) and a temperature change determining means (12) for determining whether or not the temperature change determining means (12) determines that the temperature change of the evaporator (3) per unit time is the first predetermined temperature (ΔT _K). ) follows When determining, as the temperature of the evaporator at that time (3) (T _K) the reference temperature (T _a) to the reference temperature setting means (13), after setting the reference temperature (T _a) of the evaporator whether or not the temperature (T _K) and the temperature difference between the reference temperature _{(T a) (T K -T} a) the second predetermined temperature (△ T _R) or more (3) Another temperature difference determination means (14), the temperature difference between the temperature (T _K) of the temperature difference determination means (14) is the reference temperature (T _A) and the evaporator (3) (T _K -T _A ) Is equal to or higher than the second predetermined temperature (ΔT _R ), the defrost operation end command means for outputting a command signal for ending the defrost operation to the defrost operation control means (11).
(15) A refrigerating apparatus comprising: 3. The refrigerating apparatus according to claim 2, further comprising a timer (16) for measuring a fixed time (T _D ) from the start of the defrost operation, wherein the temperature change determination means (12) includes the timer. A refrigeration system characterized in that after the time measurement in (16) is completed, it is judged whether or not the temperature change per unit time of the evaporator (3) is below the first predetermined temperature (ΔT _K ).