JPH07127954A - Refrigerating apparatus - Google Patents

Abstract

PURPOSE:To eliminate malfunction of four-way switch-over valves for stable operation upon switch-over to a cooling operation after the completion of a defrosting operation (heating operation). CONSTITUTION:Stand-by control means are provided for two refrigerant circulating systems A, B, respectively. When defrosting (heating) is completed in the system before another system, a corresponding stand-by control means switches over a four-way switch-over valve 4A or 4B to a cooling operation mode whereby a switching operation of the four-way switch-over valve 4A or 4B is ensured, thereby stably enabling having the valve standing by until the start of a simultaneous cooling operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus having a plurality of refrigerant circulation systems in which a refrigerating cycle can be reversibly switched by operating a four-way switching valve.

[0002]

2. Description of the Related Art For example, the prior art of a heat pump type heating / cooling apparatus having two refrigerant circulation systems, which is switched between cooling operation and heating operation by operating a four-way switching valve and which is defrosted by hot gas, is known. JP 61
It is known from the publicity No. 46830. As disclosed in this prior art, when frost is formed on one of the heat source side heat exchangers during heating operation, conventionally, two systems are simultaneously switched to defrost operation, and the system of which defrost is completed first is the compressor. Is stopped and made to stand by, and when both sides have completed defrosting, the four-way switching valve is switched to operate the compressor and switch to heating operation.
The same procedure is applied to refrigerators for refrigerators.

It is necessary to simultaneously start the defrosting operation in this way when the indoor units of the two refrigerant circulation systems are arranged facing each other or juxtaposed in one refrigerator. is there. That is, in a case where the indoor units are arranged to be easily affected by heat, for example, if one side is cooled and the other is operated by defrost, the defrost side is affected by the cooling air on the cooling side, and as a result, defrost cannot be performed effectively. This is because the time becomes long, which causes a disadvantage that the temperature inside the refrigerator rises. Therefore, the defrost operation is made to enter at the same time.

[0004]

When the operation is waiting until the simultaneous cooling is performed after the defrosting is completed, even if the four-way switching valve is switched to the cooling operation mode when the cooling operation is started. In many cases, the pressure difference between the high pressure and the low pressure in the refrigerant circulation system is small, and thus the switching operation is not normally performed. That is, the slide valve type four-way switching solenoid valve is often used as the four-way switching valve, and the pilot solenoid valve is usually on the cooling operation side with non-excitation and on the heating (defrost) operation side with excitation. Switch normally, but
On the other hand, the four-way switching valve on the main body side is a bowl-shaped slide valve that slides in the main body so that the pressure difference between the high-pressure chamber outside the bowl and the low-pressure chamber inside the bowl becomes a set value of 2 kg / cm ² or more. Otherwise, it will not operate smoothly. Therefore, if the standby time until the cooling operation becomes considerably long and the high / low pressure differential pressure becomes small during that time, the valve body side will not operate in the cooling operation mode even if the pilot solenoid valve is switched, and the defrost (heating) operation will not be performed. It remains in the position and cannot switch to cooling operation.

An object of the present invention is to eliminate the defective switching operation of the four-way switching valve when switching from the defrost (heating) operation to the cooling operation and to maintain stable operation.

[0006]

The present invention is a four-way switching valve 4
A plurality of refrigerant circulation systems A and B that can be switched between the cooling cycle and the defrost cycle by the switching operation of A and 4B.
In the refrigeration system in which the switching between the cooling operation and the defrosting operation is performed at the same time for all systems and the defrosting operation is individually performed for each system, the refrigerant circulation system that has completed the defrosting operation is Path switching valve 4A,
The refrigerating apparatus is characterized in that each of the refrigerant circulation systems A and B is provided with a standby control means for switching the 4B to the cooling operation mode first and waiting the operation until the simultaneous start of the cooling operation.

The present invention also includes a plurality of refrigerant circulation systems A and B which are switched between a cooling cycle and a heating cycle by switching the four-way switching valves 4A and 4B, and switching between cooling operation and heating operation is performed. In the refrigeration system, where all systems are performed at the same time and the heating operation is completed individually for each system,
Regarding the refrigerant circulation system that has finished the heating operation first, the four-way switching valves 4A and 4B are switched to the cooling operation mode first,
The refrigerating apparatus is characterized in that each of the refrigerant circulation systems A and B is provided with standby control means for making the operation stand by until the simultaneous start of the cooling operation.

[0008]

According to the present invention, the standby control means is provided for the plurality of refrigerant circulation systems A and B. When the defrosting operation or the heating operation is finished first, the standby control means operates to switch the four-way switching valves 4A and 4B to the cooling operation mode first, and make the operation stand by until the cooling operation is started all at once. . Immediately after the defrost operation is completed and the compressor is stopped, the four-way switching valves 4A and 4B are switched while the pressure difference between the high pressure and the low pressure is sufficient, so that the switching can be reliably performed, resulting in no malfunction. Thus, when the cooling operation is restarted by driving the compressor thereafter, a normal cooling cycle is secured.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a device circuit of a refrigerating machine which is an embodiment of the present invention. The embodiment shown in FIG. 1 includes an outdoor unit 1 installed in a machine room or outdoors, and two first and second indoor units 2A and 2B installed in a freezer. Two outdoor refrigerating circuits corresponding to both in-compartment units 2A and 2B are provided, and two refrigerant circulation systems A and B are provided as the entire device. Since the refrigerant circulation systems A and B have the same structure, the refrigerant circulation system A related to the first in-compartment unit 2A will be described.
The outdoor unit 1 includes a first compressor 3A, a first four-way switching valve 4A realized by a slide valve type four-way solenoid valve, a first heat source side heat exchanger 5A that functions as an air-type condenser, and a first defrost capillary. A first defrost pressure reducing device 6A and a first accumulator 9A, which are formed by connecting the tube 10A and the check valve 12A in parallel, are provided.

On the other hand, in the first internal unit 2A, a cooling decompression device 7A formed by connecting a cooling capillary tube 11A and a check valve 13A in parallel, a first utilization side heat exchanger 8A acting as an evaporator, A first drain pan heater 14A is provided. In the outdoor unit 1, the first compressor 3A
Has a discharge port connected to the high-pressure port of the first four-way switching valve 4A by a gas line, and an intake port connected to the outlet of the first accumulator 9A by a gas line. The low pressure port of the first four-way switching valve 4A is connected to the inlet of the first accumulator 9A by the gas pipe, and one switching port is connected to the coil gas side end of the first heat source side heat exchanger 5A by the gas pipe. , The other switching port is the first via the gas line
It is connected to the connecting gas line 20A. The first heat source side heat exchanger 5A is formed by an air type coil having a heat source side fan 15A, and the liquid side end port of the coil is connected to the defrosting low pressure side outlet of the first defrosting pressure reducing device 6A by a liquid line. To be done. This first defrosting pressure reducing device 6A is
The high-pressure side inlet at the time of defrosting is connected to the first connecting liquid conduit 19A via the liquid conduit.

In the first cold storage unit 2A, the first cooling decompression device 7A has a cooling high-pressure inlet side connected to the first connecting liquid pipe 19A via the first drain pan heater 14A, and a cooling low-pressure outlet. The pipe is connected to the liquid side end port of the coil of the first utilization side heat exchanger 8A. The first usage-side heat exchanger 8A is formed by an air-to-air coil having a first usage-side fan 16A, and has a first drain pan heater 14A.
A drain pan (not shown) attached to is provided directly below the coil. In this heat exchanger 8A, the coil gas side end port is connected to the first gas pipeline 20A by a gas pipeline.

Further, the outdoor unit 1 includes a first compressor 3
In order to prevent the discharge gas pressure of A from becoming higher than the set pressure, the first high pressure pressure switch for protection 17A that operates by detecting the gas pressure and the pressure of the pipeline that is on the high pressure side during defrosting are detected and defrosting ends. The defrost control first high-pressure pressure switch 18A that detects and operates by the rise of the hot gas pressure is provided, and the first indoor unit 2A detects the intake air temperature of the first usage-side heat exchanger 8A. An internal temperature thermostat 21A is provided.

In each of the refrigerant circulation systems A and B of the above embodiment, the cooling operation and the defrost operation are alternately switched by switching the four-way switching valves 4A and 4B. The four-way switching valves 4A and 4B are switched to the cooling operation mode in the non-excited state and to the defrost operation mode in the excited state. In the case of the cooling operation, the refrigerant circulation shown by the solid line arrow in FIG. 1 is performed, the latent heat of condensation is released to the outside air in the heat source side heat exchangers 5A and 5B, and the latent heat of evaporation and storage in the use side heat exchangers 8A and 8B. The inside of the refrigerator is cooled by exchanging heat with the inside air. On the other hand, in the case of the defrost operation, the refrigerant circulation shown by the broken line arrow in FIG. 1 is performed, and the hot gas is used as the utilization side heat exchangers 8A and 8A.
Defrosting is performed by being guided to the B coil and the drain pan heaters 14A and 14B. The defrosted and condensed liquefied refrigerant is decompressed and expanded by the defrosting decompression devices 6A and 6B, heat-exchanged with outside air by the heat source side heat exchangers 5A and 5B, and evaporated, and then sucked into the compressors 3A and 3B. To be done.

In this case, the cooling operation is switched to the defrost operation after being performed for 3 hours by the timer control,
The defrosting end control is individually performed for each of the refrigerant circulation systems A and B, and when the defrosting of both systems is completed or when the timer control is performed for half an hour, for example, the cooling operation is simultaneously switched.

FIG. 2 shows a flow chart of the operation control mode of this embodiment, and FIG. 3 shows the operation of the driving equipment in comparison with the prior art. The operation control of the above embodiment will be described with reference to FIGS. 1 to 3. In step m1, the cooling operation is started for both the first and second refrigerant circulation systems A and B, and at the same time, the defrost cycle is counted by the timer, for example, 3 hours. When the refrigerator operation is continued and it is checked that the next step m2 has reached the defrost period of 3 hours, the process moves to step m3, and both systems A and B are simultaneously switched to the defrost operation. During the defrosting operation, as shown in FIG.
Operated, the four-way switching valves 4A and 4B were excited, and both fans 1
5A, B, 16A, B are stopped.

During the defrost operation, the following steps m4 and m
In step 5, it is checked which of the systems A and B is to be defrosted first. If the system A completes the defrosting first, the process moves to step m6, and the standby control means of the system A operates to stop the defrosting operation of the system A and put it in a standby state. This standby state is shown in FIG. 3, but the compressor 3A is stopped and the four-way switching valve 4A is switched from energized to de-energized to enter the cooling operation mode. At this time, the four-way switching valve 4A has a large difference between the high pressure and the low pressure, so that the switching movement is smoothly performed.

While the system A is on standby, the process moves to step m7 to check the defrost of the system B. When the end of defrost is detected, the process goes to step m10 to start the timing of the defrost cycle. Step m1
Then, the cooling operation is started simultaneously for both systems A and B.

System B at steps m4 and m5
If defrost finishes first, step m8,
Move to m9, m10 and step m1 in sequence
In the same manner as the standby in the case of 1, the standby of system B and the shift to the simultaneous cooling operation are performed.

The embodiment shown in FIG. 1 is an example in which the cooling operation and the defrosting operation are switched by the switching operation of the four-way switching valve. There may be a case where a refrigerating apparatus having a plurality of refrigerant circulation systems switched to the heating cycle is used, and switching between the cooling operation and the heating operation is performed at the same time for all the systems, and the end of the heating operation is performed individually. As for the refrigerating apparatus in which the operation control is performed, as in the above-described embodiment, the four-way switching valve is first switched to the cooling operation mode for the refrigerant circulation system that has finished the heating operation, and the cooling operation is made to wait for the cooling operation. This makes it possible to eliminate the malfunction of the four-way switching valve, and the configuration of such a refrigeration system is also included in the scope of the present invention.

[0020]

As described above, according to the present invention, the refrigerant circulation system that waits until the simultaneous cooling operation is completed after the defrost (heating) operation is completed is switched to the four-way by the completion of the defrost (heating) operation. By switching the valve to the cooling operation mode, it can be switched while the high / low pressure difference of the refrigerant is sufficient, and as a result, switching can be reliably performed and malfunction of the four-way switching valve at the start of cooling operation can be eliminated. , Stable operation can be achieved.

[Brief description of drawings]

FIG. 1 is a device circuit diagram of an embodiment of the present invention.

FIG. 2 is a flow chart illustrating a mode of operation control of the embodiment shown in FIG.

FIG. 3 is a chart showing the operation of the driving equipment of the embodiment shown in FIG.

[Explanation of symbols]

 A, B Refrigerant circulation system 1 Outdoor unit 2A, 2B Internal unit 3A, 3B Compressor 4A, 4B Circuit switching valve

Claims (2)

[Claims] 1. A plurality of refrigerant circulation systems A and B which can be switched between a cooling cycle and a defrost cycle by a switching operation of four-way switching valves 4A and 4B, and switching between the cooling operation and the defrost operation is performed simultaneously for all the systems. In the refrigeration system that is performed and the defrost operation is completed individually for each system, for the refrigerant circulation system that completed the defrost operation first,
A refrigeration system characterized in that each of the refrigerant circulation systems A, B is provided with a standby control means for switching the four-way switching valves 4A, 4B to the cooling operation mode first and for making the operation standby until the simultaneous start of the cooling operation. 2. A plurality of refrigerant circulation systems A and B which can be switched between a cooling cycle and a heating cycle by switching operation of the four-way switching valves 4A and 4B, and switching between cooling operation and heating operation is performed simultaneously for all systems. In the refrigeration system, in which the heating operation is performed and the heating operation is finished individually for each system, the four-way switching valves 4A and 4B are switched to the cooling operation mode first for the refrigerant circulation system that has finished the heating operation.
A refrigerating apparatus, characterized in that standby control means for holding the cooling operation until the start of the cooling operation is provided in each of the refrigerant circulation systems A and B.