JPH1183216A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To materialize the power saving, the refrigerant saving, the simplification of installation work, etc., by cooling a group of showcase or the like divided into systems with a large-output refrigerator. SOLUTION: This refrigerator comprises a plurality of coolers 1a-1j which are divided separately for each system, according to the required cooling temperature of accommodated cold-storage goods, and are equipped with evaporators different in heat exchange efficiency separately for each system so that the evaporation temperature may be roughly fixed, a freezer 2 which has a capacity control function from the equivalent to the lowest load of all systems to the equivalent to the highest load, and a refrigerant pipe 3 which connects the coolers 1a-1j with the freezer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a refrigeration system,
In particular, the present invention relates to a refrigeration apparatus that cools a plurality of showcases and refrigerators having different cooling temperatures depending on products, such as a supermarket, using a refrigerator.

[0002]

2. Description of the Related Art Conventionally, in a supermarket or the like, when a large-scale refrigeration system is constituted by a refrigerator and a refrigerator such as a freezer / refrigerator showcase or a prefabricated refrigerator, the cooling of the showcase and the like is required. The refrigerators are systematized according to the required capacity of the refrigerator and the required capacity, and a plurality of them are installed for the required system.

[0003] In general supermarkets, excluding frozen commodities such as popsicles, daily and dairy products (cooling temperature: 3-7 ° C), fruits and vegetables (5-10 ° C), meat and meat
There are three refrigerated lines of fresh fish (−5 to 2 ° C.). From the viewpoint of the evaporation temperature, the showcase for daily / dairy products and fruits and vegetables is −10 ° C., while the showcase for meat and fresh fish is −17 ° C.

For example, FIG. 5 is a schematic diagram showing a conventional example of the layout and operating state of a showcase group, a refrigerator and a refrigerator in a supermarket. Here, the showcase groups 1a to 1i and the refrigerator 1j are divided into the three systems described above, and the first to third refrigerators 2a to 2c are respectively arranged and connected by the refrigerant pipes 3a to 3c. The solenoid valves 4a to 4j are provided for each of the showcases, the showcase groups 1a to 1i, and the refrigerator 1j. Each of the refrigerators 2a to 2c
By combining two or three compressors from among three types of compressors (compressors) of general 10 hp (HP), 15 hp and 20 hp, an output of 25 to 45 hp can be obtained. Things.

[0005]

By the way, in selecting equipment of a conventional refrigeration system, when performing load estimation calculation, a safety factor (margin factor) of 30% is added to the refrigeration capacity derived from necessary equipment. , The selection of the refrigerator output of the system.

For example, the required refrigerating capacity of each of the three types of showcase groups 1a to 1i and the refrigerator 1j is represented by (A) kcal / h, (B) kcal / h, and (C).
If kcal / h, the refrigerating function is (A + B + C) ×
1.3 or more is required. The safety factor (margin factor) is 30%
Breakdown of piping pressure loss: 10%, outside air temperature correction: 10
%, Pull-down support after defrosting (load increase after defrosting): 10%. The 10% load increase after defrosting is expected for the following reasons.

In the conventional refrigeration system, defrosting of the evaporator is performed by first stopping the chiller of the defrosting system, melting the frost adhering to each evaporator of the system, and then operating the chiller of the system again. Is generally used. In this method, the load on the refrigerator after the completion of defrosting temporarily increases.

That is, in FIG. 5 described above, the first refrigerator 2a is stopped while the showcase groups 1a to 1d connected to the first refrigerator 2a are being defrosted, and the solenoid valves 4a in the refrigerant pipe 3a are stopped. ４4d are closed. Maximum load occurs after this defrost. That is, since the load of all the showcase groups 1a to 1d connected to the first refrigerator 2a increases at once, the load of the first refrigerator 2a increases significantly.

Each of the refrigerators 2a to 2c is composed of a plurality of compressors (compressors) and other element parts such as a condenser (condenser), and their outputs are 25 to 45 horsepower as described above. However, if a selection is made for a refrigeration system that requires a refrigeration capacity exceeding 45 horsepower in all systems, depending on the combination, the output must be selected more than necessary.

That is, the output configuration of this type of conventional refrigerator has a power of 25, 30, 35, and 45 horsepower. In this output configuration, selection of a refrigerator having a useless output for one system of the showcase group is performed. Occurred many times. This causes an increase in equipment cost and a decrease in operating efficiency for each system, and further increases wasteful output (power consumption) by the number of systems in the showcase group.

For example, assuming that the required freezing capacity of the showcase group is 20 hp for fruits and vegetables, 17 hp for meat and fresh fish, and 24 hp for daily and dairy products, the above-mentioned safety factor of 30
The refrigeration capacity, with the addition of%, is 26 hp for fruits and vegetables, 22.1 hp for meat and fresh fish, and 31.2 hp for daily and dairy products. Therefore, a refrigerator of 30 hp is required for fruits and vegetables, and a refrigerator of 25 hp for meat and fresh fish.
A chiller of 35 hp for dairy products is required.

That is, when the safety factor of 30% is sufficient for the total of 79.3 horsepower, the total of three refrigerators becomes 90 horsepower, and the output is selected more than necessary. By the way, the amount of refrigerant is also almost proportional to the refrigerating capacity, 95 kg at 30 hp, 80 kg at 25 hp, 115 k at 35 hp
g is required, for a total of 290 kg.

Further, as shown in FIG. 6, when the showcase load per day measured in a certain supermarket is examined, the load ratio during the opening hours varies between 60% and 100%. The load factor at night after the store is covered by the cover is approximately 20% as indicated by the thick line.
Therefore, in order to reduce power consumption, a refrigerator having a wide capacity control range capable of coping with the 20% load at night is required.

Investigation of the annual cost of a certain supermarket shows that electricity costs occupy the second place in terms of personnel costs, and refrigeration equipment consumes considerably more power than lighter equipment such as lighting and registers. From this, it can be seen that the reduction of the electricity cost of the refrigeration system greatly contributes to the improvement of the profit of the supermarket.

Further, in the above example, the installation work of the refrigerators 2a to 2c for the three systems and the respective piping work are required, which requires much labor and time.

Accordingly, the present invention has been made to solve such a problem, and the showcases and the like, which have been systematized, are cooled by a single high-power refrigerator to save power and refrigerant. It is an object of the present invention to provide a refrigeration apparatus capable of simplifying installation work and the like.

[0017]

In order to achieve the above-mentioned object, the present invention is directed to a system wherein the system is divided according to the required cooling temperature of the stored refrigerated goods, and the evaporation temperature is substantially constant. A plurality of coolers provided with evaporators having different heat exchange efficiencies, a refrigerator having a capacity control function from a minimum load equivalent to a maximum load equivalent of the entire system of the coolers, and the cooler And a refrigerant pipe for connecting to the refrigerator.

Further, a service valve is provided in a main part of the refrigerant pipe.

The cooler is provided with a defrost timer, and each system of the cooler is further divided into blocks so that the setting of the defrost timer is the same for each block, and during the operation of the refrigerator. A defrosting means for sequentially performing a defrosting operation of the cooler for each block is provided.

Further, the refrigerator comprises a plurality of compressors and is provided with at least one compressor having a capacity corresponding to the minimum load of the entire system of the cooler.

Further, it is arranged on the low pressure side of the refrigerant pipe,
A low-pressure switch for controlling ON / OFF of the plurality of compressors according to a predetermined value of the low-pressure side pressure is provided.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a layout of a group of coolers such as a showcase and a refrigerator in a refrigerator according to an embodiment of the present invention and an operation state thereof.

As shown in the drawing, the showcase groups 1a to 1
i and the refrigerator 1j are divided into three systems in substantially the same manner as described above, one high-power refrigerator 2 is arranged, the refrigerant pipes 3 are connected, and each showcase or showcase group 1 in each system is connected.
a to 1i, and solenoid valves 4a to 4j are provided for each refrigerator 1j. In the figure, one showcase group 1a in which the inside of one system is further finely blocked is being defrosted, and its solenoid valve 4
a is closed, but the other showcase groups 1b-1i
In addition, the refrigerator 2 operates without stopping while the solenoid valves 4b to 4j of the refrigerator 1j are kept open.

The refrigerator 2 is provided with a plurality of compressors and has a capacity control function from the minimum load equivalent to the maximum load of all of the three cooler groups 1a to 1j.
The refrigerator 2 having the optimum output is selected by a new defrosting method described later and a load estimating method based thereon.

Also, the cooling temperature of the cooler groups 1a to 1j of the respective systems in which the evaporating temperature becomes the same by using one refrigerator is required by making the heat exchange efficiency of the evaporators provided therein different. A cooling temperature is provided. Specifically, the evaporating temperature was unified to -10 ° C for conventional day-daily / dairy products and showcases for fruits and vegetables, and
The meat and fresh fish showcase at 17 ° C. has a required cooling temperature of -5 by increasing the size of the evaporator, that is, increasing the surface area of the fins to improve the heat exchange efficiency of the evaporator.
To 2 ° C.

Although not shown, the solenoid valve 4
a to 4j, each showcase 1a to 1i and refrigerator 1
A service valve is attached to a main part of the refrigerant pipe connected to j for easy operation. As a result, even if a leak or the like occurs in a part of the refrigerant pipe 3 connected from one refrigerator 2 to the entire system, the refrigerator 2
The service valve provided on the side is closed, and the refrigerator 2 can be repaired while it is running, so that the entire system can be prevented from shutting down for partial repair.

Each of the coolers is provided with a defrost timer, and the defrost timers whose operation times are shifted open and close the solenoid valves 4a to 4j provided for each block, so that freezing is performed. While the operation of the machine 2 is continued, the defrosting operation of the coolers 1a to 1j for each block is performed sequentially (sequentially). As a result, the load fluctuation of the refrigerator 2 is reduced and stabilized, and the temperature inside the refrigerator or the showcase is stabilized. That is, since the load applied to the refrigerator 2 is stabilized, the power consumption of the refrigerator 2 is reduced, and the temperature recovery after defrosting of a cooler such as a showcase or a refrigerator is quicker, so that the temperature controllability is also improved. I do.

By adopting such a new defrosting method and appropriately performing the blocking, the load increase after the defrosting is dispersed, and it becomes extremely small as a whole.
Therefore, it becomes almost negligible for the high-power refrigerator 2 having the capacity control function, and there is no problem even if the safety factor used for calculating the load estimation is reduced from 30% of the conventional one to almost 20%.

FIG. 2 is a refrigerant circuit diagram of the refrigerator 2 of the present embodiment. This refrigerator 2 has four compressors 20a to 20d (75 hp) in total, one for 15 hp and three for 20 hp to cope with a 20% load at night, and two compressors are connected by a common pipe. Have been. That is, the first compressor 20
a and mufflers 21a, 21a in the discharge pipe of the second compressor 20b.
Refrigerant pipes 22a and 22b connected via b are joined on the way, and connected to an oil separator (oil separator) 23a for the first and second compressors. Similarly, mufflers 21c, 21c are provided in discharge pipes of the third compressor 20c and the fourth compressor 20d.
Refrigerant pipes 22c and 22d connected via 21d join on the way, and are connected to an oil separator 23b for the third and fourth compressors.

Further, the first compressor 20a and the second compressor 20
Refrigerant pipes 24a and 24b connected to the suction pipe b join in the middle and connected to accumulators (gas-liquid separators) 25a for the first and second compressors. Similarly, refrigerant pipes 24c and 24d connected to the suction pipes of the third compressor 20c and the fourth compressor 20d join on the way, and are connected to accumulators 25b for the third and fourth compressors. The discharge pipe and the suction pipe of each of the compressors 20a to 20d are provided with maintenance service valves 26a to 26d and 27a to 27d.

The refrigerant pipes 28a and 28b which have come out of the oil separators 23a and 23b are joined to provide a total of three sets of two refrigerant pipes. 30f. On the input side of each of the capacitors 30a to 30f,
Service valves 31a to 31c are provided for each unit, and service valves 32a to 32f are individually provided on the output side. Further, one side of the output of each unit is provided with high-pressure switches 33a to 33c for backup of the temperature sensor for controlling the fan motor.

The refrigerant pipes that have exited from the condensers 30a to 30f join and are connected to a receiver tank (liquid receiver) 34. The receiver tank 34 is provided with service valves 35 and 36 on the inlet and outlet sides of the refrigerant pipe, and a high-pressure manometer via a safety valve 37, a fusible plug 38, a check valve 38 and a capillary tube 39. 40 are attached.

The refrigerant pipe that has exited the receiver tank 34 is drawn out of the refrigerator 2 as a high-pressure liquid pipe 43 via a filter dryer 41 and a moisture indicator 42, and as shown in FIG. It is branched and connected to each of the showcase groups 1a to 1i and the refrigerator 1j via the solenoid valves 4a to 4j.

Each of the showcase groups 1a to 1i and the refrigerator 1
The refrigerant pipes from j are joined to form one common pipe 3 and connected to the suction pipe 44 of the refrigerator 2, and the accumulator 25 a for the first and second compressors and the accumulator 25 a for the third and fourth compressors It is input to the accumulator 25b. A service stop valve 46 is connected to the suction pipe 44 and the low pressure manometer 4
7. A low pressure switch 48a for the first and second compressors and a low pressure switch 48b for the third and fourth compressors are attached.

The low pressure switch 48a for the first and second compressors and the low pressure switch 4a for the third and fourth compressors
Reference numeral 8b denotes a digital pressure switch that can set two different types of ON / OFF pressures.
It is provided for capacity control of 20d. That is, the four low-pressure switches 48a and 48b are different from each other.
Various ON / OFF pressures can be set. One compressor can be operated (20% load at night) to four compressors (10 daytime).
Wide capacity control up to 0% load) is possible.

On the other hand, the refrigerant pipe 49a exiting from the accumulator 25a for the first and second compressors is branched and connected to the suction pipes of the first and second compressors 20a and 20b. The refrigerant pipe 49b that has exited from the compressor accumulator 25b branches off into a third compressor 20c and a fourth compressor 2c.
0d is connected to the suction pipe.

The high-pressure liquid pipe 43 downstream of the moisture indicator 42 is supplied with high-pressure liquid refrigerant by each compressor 20.
A liquid injection pipe (L / I pipe) 50 for cooling each of the compressors 20a to 20d with the heat of evaporation by returning to evaporate by returning to a to 20d is connected. The L / I pipe 50 is branched into four pipes for each compressor on the way, and the service stop valves 51a to 51d are respectively provided.
d, each of the compressors 20a to 52d through the solenoid valves 52a to 52d and the capillary tubes 53a to 53d for evaporation under reduced pressure.
It is input to the low pressure side of 20d.

On the other hand, the first and second compressor oil separators 23a and the third and fourth compressor oil separators 2a
An oil tank 54 for storing the separated lubricating oil is connected to 3b. Service valves 55 and 56 are provided on the inlet side and the outlet side of the oil tank 54. The pipe connected to the service valve 56 at the outlet of the oil tank is branched into four pipes for each compressor on the way, and each of the compressors 20a to 20d is connected via a service stop valve 57a to 57d and an oil regulator 58a to 58d, respectively. 20d. The oil tank 54 is connected to the suction pipe 44 of the refrigerator 2 via an oil tank pressure equalizing piping service valve 59.

The compressor 2a detects an abnormally high pressure or an abnormally low pressure on the high pressure side and the low pressure side of each of the compressors 20a to 20d.
High / low pressure switch 60 for protecting 0a-20d
a to 60d are capillary tubes 6 for stabilizing pressure.
They are connected via 1a to 61d.

In the present embodiment, since various service valves are provided in the above-described main part also in the refrigerator 2, even if a leak or the like occurs in a part of the refrigerant pipe or the like, it is provided on both sides of the part. By closing the service valve and repairing the refrigerator while it is running, it is possible to prevent the entire system from being stopped due to partial repair.

The refrigerator 2 of the present embodiment having the above-described structure is installed outdoors, and has a high-pressure liquid pipe 43 and a suction pipe 44.
Are connected to the showcase groups 1a to 1i and the refrigerator 1j in the supermarket by the refrigerant pipe 3, as shown in FIG. In this case, installation work of one refrigerator and piping work thereof can be completed, so that the installation work can be simplified.

The refrigerator 2 of this embodiment has four compressors 2
0a to 20d are the low pressure switches 48a for the first and second compressors and the low pressure switches 48 for the third and fourth compressors as described above.
b, the capacity control operation is automatically performed. For example, when the load is 20% at night when the showcase is covered,
One horsepower compressor operated, 100% in daytime after opening
At the time of load, four compressors are operated.

The high-pressure high-temperature refrigerant compressed by each of the compressors 20a to 20d joins to form the oil separators 23a and 23b.
The lubricating oil mixed with the refrigerant is separated from the refrigerant, and the separated lubricating oil is temporarily stored in an oil tank 54, and is operated by the oil regulators 58a to 58d as necessary.
The values are returned to 0a to 20d.

The high-pressure and high-temperature refrigerant having passed through each of the oil separators 23a and 23b joins and is divided and supplied to three units of air-cooled condensers 30a to 30f.
The liquid is condensed and liquefied by forced air cooling by the
Stored in 4.

From the receiver tank 34, the high-pressure liquid refrigerant is supplied stably to the showcase groups 1a to 1i and the refrigerator 1j connected to the refrigerator 2 via the filter dryer 41 and the moisture indicator 42. The high-pressure liquid refrigerant supplied to the showcase groups 1a to 1i and the refrigerator 1j is decompressed and expanded by passing through the expansion valve, and is supplied to an evaporator (evaporator). In the evaporator, the inside of the refrigerator is cooled by the heat of vaporization of the liquid refrigerant that has been decompressed and expanded, and is maintained at a cooling temperature according to the heat exchange efficiency.

In the present embodiment, as described above, the cooling temperatures of the showcase groups 1a to 1i and the refrigerator 1j of each system in which the evaporation temperature is the same by using one refrigerator 2 are provided to them. The required cooling temperature can be obtained by making the heat exchange efficiency of the evaporator different. Here, the evaporating temperature is unified to -10 ° C, such as a display case for daily delivery, dairy products, fruits and vegetables, fruits and the like.
That is, the required cooling temperature is obtained by improving the heat exchange efficiency of the evaporator by increasing the surface area of the fin or the like.
5 ° C. to 2 ° C. is obtained.

In this manner, the low-pressure refrigerant gas that has cooled the showcase groups 1a to 1i and the refrigerator 1j of each system is returned to the suction pipe 44 of the refrigerator 2 through the refrigerant pipe 3, and is stored in the accumulator 25a. , 25b, and only the gaseous components are returned to the compressors 20a to 20d and recompressed, and the refrigeration cycle is repeated.

During this time, each of the compressors 20a to 20d is connected to an opening / closing store, a showcase group 1a to 1i at day and night, and a refrigerator 1
The capacity control operation is automatically performed by the first and second compressor low-pressure switches 48a and the third and fourth compressor low-pressure switches 48b according to the load fluctuation of j. Therefore, the refrigerator 2
Operating state of the showcase group 1a-1i and the refrigerator 1j
Is maintained at the minimum required power to maintain the required cooling temperature of each.

Here, in the conventional system, as described above, the total output of the three chillers 2a to 2c of the three systems is individually 30% safety factor for the required refrigeration capacity of 61 horsepower of all the systems.
In consideration of the above, it is necessary to select a refrigerator more than 90 horsepower in total, the required amount of refrigerant is also 290 kg, but in the system of the present embodiment, for the same total system required refrigeration capacity 61 horsepower, With the new defrosting method (sequential defrosting method) described above, the value taking into account the safety factor of 20%, which suppresses the load increase after defrosting, is 73.2 horsepower, so one 75 horsepower unit is sufficient and the refrigerant amount is 240 kg. It became. As a result, horsepower is reduced by 17%,
This means that the refrigerant amount was reduced by 17%.

Next, the reduction in power consumption by the refrigeration apparatus of this embodiment will be described. The graph in FIG. 3 shows a change in power for one day. The dotted line is the refrigeration apparatus of the present embodiment, and the solid line is the conventional refrigeration apparatus. As a result of coping with the capacity controllability of the refrigeration apparatus in the present embodiment in a time zone of a 20% load at night, a large reduction in the amount of power is achieved. In addition, a large reduction in the amount of power is achieved by the effect of output optimization and the effect of sequential defrost.
As a result of analyzing this data, about 18.5% throughout the year
Power consumption is expected to decrease.

By the way, as a result of collecting various information about a supermarket as an optimum output refrigerator, it was found that the refrigerator needs a series configuration (11 models) ranging from 45 to 95 horsepower in increments of 5 horsepower. .

Therefore, in the present invention, as shown in FIG. 4, in order to develop a refrigerator having a wide capacity control range corresponding to a 20% load at night, as shown in FIG.
A multi-compressor system of up to 5 units combining a horsepower (HP) refrigerator with 10, 15, and 20 horsepower compressors (compressors) is adopted, and 11 models from 45 to 95 horsepower can be realized in 5 horsepower increments. I did it.

[0054]

As described above, according to the present invention, the refrigerated goods are divided according to the required cooling temperature of the stored refrigerated goods, and the heat exchange efficiencies differ from one system to another so that the evaporation temperature becomes substantially constant. A plurality of coolers provided with an evaporator, one refrigerator having a capacity control function from a minimum load equivalent to a maximum load equivalent of the entire system, and a refrigerant pipe connecting the cooler and the refrigerator. Therefore, excessive output of the refrigerator can be suppressed, and power saving, refrigerant saving, installation work simplification, and the like can be achieved.

Further, since a service valve is provided in the main part of the refrigerant pipe, even if a leak or the like occurs in a part of the refrigerant pipe, the service valve corresponding to the part is closed to operate the refrigerator. By repairing as it is, it is possible to prevent the entire system from stopping due to partial repair.

The cooler is provided with a defrost timer, and each system of the cooler is further divided into blocks so that the setting of the defrost timer is the same for each block. Since the defrosting means for sequentially performing the defrosting operation of the cooler is provided, the load applied to the refrigerator is stabilized, the power consumption of the refrigerator is reduced, and the temperature recovery after the defrost of the cooler is also quickened. Therefore, the temperature controllability is also improved.

Further, since the refrigerator comprises a plurality of compressors and at least one compressor having a capacity corresponding to the minimum load of the entire system of the cooler, the refrigerator can be used at night when the cover is mounted on the showcase. It is possible to easily cope with the minimum load time zone, and to achieve a significant reduction in power consumption.

Each compressor is controlled by a low-pressure switch, so that the cost can be reduced as compared with the control using a microcomputer.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a layout of a cooler group such as a showcase and a refrigerator in a refrigerator according to an embodiment of the present invention and an operation state thereof.

FIG. 2 is a refrigerant circuit diagram of the refrigerator of the embodiment.

FIG. 3 is a diagram showing a daily power change amount in the supermarket of the embodiment and the conventional example.

FIG. 4 is a diagram showing a model configuration according to the present invention.

FIG. 5 is a schematic diagram showing a conventional example of a layout and operating states of a showcase group, a refrigerator and a refrigerator in a supermarket.

FIG. 6 is a diagram showing a change in load per day for a showcase.

[Explanation of symbols]

1a-1i Showcase 1j Refrigerator 2 Refrigerator 3, 22a-22d, 24a-24d, 28a, 28
b, 49a, 49b Refrigerant piping 4a to 4j, 52a to 52d Solenoid valve 20a to 20d Compressor 23a, 23b Oil separator 25a, 25b Accumulator 26a to 26d, 27a to 27d, 31a to 31c, 3
2a to 32f, 35, 36, 51a to 51d, 55, 5
6 Service valve 54 Oil tank 34 Receiver tank 30a-30f Condenser 48a, 48b Low pressure switch

Continued on the front page (72) Inventor Tomoyuki Shiomi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Eiichi Shimizu 2-5-1-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Kensuke Oka 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (5)

[Claims] 1. A plurality of coolers which are divided for each system according to a required cooling temperature of stored refrigerated goods, and which are provided with evaporators having different heat exchange efficiencies for each system so that an evaporation temperature becomes substantially constant. A refrigerating apparatus comprising: one refrigerator having a capacity control function from a minimum load equivalent to a maximum load equivalent of the entire system of the cooler; and a refrigerant pipe connecting the cooler and the refrigerator. 2. The refrigeration system according to claim 1, wherein a service valve is provided in a main part of the refrigerant pipe. 3. The cooler includes a defrost timer and further blocks each system of the cooler so that the setting of the defrost timer is the same for each block. The refrigerating apparatus according to claim 1 or 2, further comprising a defrosting unit that sequentially performs a defrosting operation of the cooler for each of the blocks. 4. The refrigerator according to claim 1, wherein the refrigerator comprises a plurality of compressors and at least one compressor having a capacity corresponding to a minimum load of the entire system of the cooler. The refrigeration apparatus according to any one of the above. 5. A compressor according to claim 1, wherein said plurality of compressors are turned on / off in accordance with a predetermined value of said low pressure side pressure.
The refrigeration apparatus according to claim 4, further comprising a low-pressure switch that controls OFF.