JPH08271063A - Refrigerator for store - Google Patents

Abstract

PURPOSE: To reduce the load capacity which is largely varied to the minimum limit by providing a flow control valve for controlling the liquid injection amount in a liquid injection tube, controlling the valve in response to the temperature of the discharge gas of a scroll compressor, and further providing a switching valve at the tube for introducing refrigerant to each chilled case. CONSTITUTION: A liquid receiver 30 is provided at the downstream side of a refrigerating cycle outdoor heat exchanger 20, and the receiver 30 or its downstream side is connected to the compressing chamber of a scroll compressor 10 via a liquid injection tube 85. A flow control valve 80 for controlling the liquid injection amount is provided at the tube 85, and is controlled by a controller 201 in response to the temperature of the discharged gas of the compressor 10. Further, a solenoid switching valve 35 is provided at the tube for introducing the refrigerant to the case. Thus, a plurality of small-sized cold storage display cases are installed, can be operated in response to the capacity for the load capacity which is largely changed, thereby providing the energy conservation effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a store refrigeration system,
In particular, it is suitable for use by connecting 5 to 7 small capacity showcases (chilled cases) to one refrigerator such as a convenience store.

[0002]

2. Description of the Related Art An air-cooled condenser unit is installed outdoors and a compressor unit is installed in an indoor machine room. The compressor is controlled by an inverter to control the capacity by controlling a reduction in refrigerating capacity. An example of carrying out is described in JP-A-60-175970.

[0003]

In the conventional refrigeration system,
The reciprocating type in which an inverter is used and the compressor reciprocates is often used, and there are the following problems.

(1) Originally, the fluctuation of the rotational torque of the compressor is large, and the inertial force may decrease at low frequency operation, resulting in stall. On the contrary, at high frequency operation, the discharge gas temperature of the compressor may rise abnormally. In some cases, excessive stress acted on the discharge valve and suction valve in the compressor. Therefore, it has not been possible to sufficiently cope with a wide range of capacity and high precision and fine operation.

(2) The pulsation of the high-pressure discharge gas discharged from the compressor is large, and when the number of revolutions of the compressor is changed by the inverter, the pulsation may be further amplified.
For this reason, there are many restrictions on the route through which the refrigerant pipe passes and the construction method in order to prevent the flow noise of the refrigerant gas generated in the refrigerant pipe and the vibration of the pipe itself.

(3) Vibration and noise of the compressor itself are large, and when the rotation speed of the compressor is changed, the vibration and noise are further amplified. Therefore, there were many restrictions on the structure of the machine room, installation in residential areas in urban areas, and driving at night.

An object of the present invention is to enable operation in accordance with the load capacity that fluctuates greatly by installing a plurality of small refrigerating showcases, such as 5 to 7, and achieve an energy saving effect, and showcases. It can be finely controlled to minimize temperature fluctuations inside, low noise, space saving,
The purpose is to obtain a refrigerating device for a store, which is advantageous for trial operation, service, response and display in case of failure.

[0008]

In order to achieve the above object, the first feature of the refrigerating apparatus for a store of the present invention is that the refrigerating apparatus for a store is provided in the store, and at least 3 which is kept at a temperature of about 2 ° C.
Chilled case above the table, walk-in case installed in the backyard of the store to keep the internal temperature at around 5 ° C, scroll compressor installed in a machine room in close proximity, and inverter control for this A drive device for driving with, a heat exchanger provided outdoors, the chilled case,
A pipe that forms a refrigeration cycle by sequentially connecting a walk-in case, a scroll compressor, and an outdoor heat exchanger, a liquid receiver provided on the downstream side of the refrigeration cycle outdoor heat exchanger, and the inside or the liquid receiver. A liquid injection pipe connecting a downstream side and a compression working chamber of the scroll compressor, a flow control valve for controlling a liquid injection amount provided in the liquid injection pipe, and a temperature of discharge gas of the scroll compressor. And a control valve for controlling the control valve, and an on-off valve provided in each pipe for guiding the refrigerant to each of the chilled cases.

[0009] Further, preferably, the store may be a store that conducts sales activities for 2/3 or more of a day.

Further, preferably, the controller may control the flow rate control valve so that the degree of superheat of the refrigerant downstream of the compressor becomes constant.

Preferably, one end of the liquid injection pipe may be opened so as to communicate with the compression working chamber at a position within one wrap from the discharge port of the scroll compressor.

[0012] Preferably, the chilled case has a width of 3 and five or more units are connected to one refrigeration cycle unit.

Further, preferably, the drive device for driving the compressor under inverter control judges an inverter failure,
A means for automatically switching to a commercial power source and continuing the operation may be provided.

Further, preferably, the drive device for the scroll compressor comprises means for controlling the number of revolutions according to suction pressure,
It may be provided with a means for operating at a fixed rotation speed.

Further, it is preferable to have means for digitally displaying the operating state (each pressure, temperature, degree of superheat, number of revolutions) of the refrigeration system, reason for stopping, and reason for abnormal stopping.

In order to achieve the above-mentioned object, the second feature of the store refrigeration system of the present invention is that at least three chilled cases in which the internal temperature of the store is maintained at around 2 ° C.,
In a refrigeration system provided with a walk-in case for keeping the internal temperature at around 5 ° C, a scroll compressor provided in a machine room installed indoors close to the store, and suction of the scroll compressor. A suction pressure sensor for detecting the operating suction pressure, a means for controlling the number of revolutions of the scroll compressor by changing the frequency of the inverter according to the value of the suction pressure sensor, and provided outdoors.
The chilled case, walk-in case, scroll compressor and a refrigeration cycle unit consisting of an air-cooled condenser that is sequentially connected by piping, and a receiver provided on the downstream side of the air-cooled condenser of the refrigeration cycle unit. A liquid injector, a liquid injection pipe connecting the inside of the liquid receiver or a downstream side thereof and a compression working chamber of the scroll compressor, and a flow control valve for controlling a liquid injection amount provided in the liquid injection pipe, A discharge gas thermistor for detecting the temperature of the discharge gas of the scroll compressor, and a high pressure sensor for detecting the pressure on the discharge side of the scroll compressor,
The discharge gas thermistor and means for controlling the opening of the flow rate control valve based on the values of the high pressure sensor, and electromagnetic on-off valves provided in respective pipes for introducing the refrigerant to the chilled cases are provided.

Preferably, the chilled case has a width of about 1 m, and five or more units may be connected to the refrigeration cycle section.

Preferably, means for judging the failure of the inverter, and means for continuing the operation by switching the power supply of the scroll compressor to the commercial power supply when the judgment means judges that the failure has occurred. Is to have.

Further, preferably, it has means for digitally displaying at least the pressure and temperature of each part and the number of revolutions of the scroll compressor as an operating state, and means for displaying a reason for stopping and a reason for abnormal stopping.

In order to achieve the above object, the third feature of the store refrigerating apparatus of the present invention is that the number of revolutions is controlled by the refrigerator main body provided in the machine room and the inverter, and the liquid injection amount is controlled. The scroll compressor, at least three or more chilled cases, a walk-in case, a pipe for guiding the refrigerant to the chilled case, and an on-off valve for detachably attaching the chilled case to the pipe are provided.

[0021]

According to the present invention, there are the following actions.

(1) By using the scroll compressor in the refrigerating device, the fluctuation of the rotating torque is small, so that it does not stall even at low frequency operation, and it is not difficult even at high frequency operation, so it is stable in a wide range. By controlling the compressor suction speed by detecting the operating suction pressure and changing the frequency of the inverter, the capacity can be varied over a wide range and highly precise and delicate operation can be performed. In addition, since a compressor originally having small torque fluctuation is provided in a dedicated machine room and the number of revolutions is changed by an inverter, vibration and noise in the entire refrigeration system can be reduced, and high-pressure gas discharged from the compressor can be reduced. The pulsation is small and the flow noise of the refrigerant gas generated in the refrigerant pipe and the vibration of the pipe itself can be reduced, and the restrictions on the route through which the refrigerant pipe is passed and the construction method are reduced. Furthermore, since the temperature and pressure of the discharge gas are detected, the amount of liquid injection into the compression working chamber of the compressor is controlled, and the position where the refrigerant liquid is injected is the intermediate pressure part of the scroll compressor, the suction side of the compressor It is possible to obtain a stable discharge gas temperature without excessively heating up to a high operating frequency while maintaining the refrigeration capacity, without reducing the suction amount of the refrigerant gas from.

(2) Means for determining a failure of the inverter and means for continuing the operation by switching the power source of the scroll compressor to a commercial power source when the determination means determines a failure By this, when the inverter fails, it automatically switches to the commercial power supply, so that the finest temperature control is not possible but the necessary minimum refrigeration operation is possible, and it is possible to avoid adverse effects on the items stored in the showcase. .

(3) Since the driving device of the scroll compressor is provided with a fixed-frequency operation, services such as expansion valve adjustment and refrigerant charging at the time of trial operation can be changed with a normal suction pressure. It can be easier than driving.

(4) By displaying each of the operating states, the refrigeration system can be regularly checked to prevent failures, and the reason for the abnormal stop is displayed, so that the operating range is appropriate. It will be easier to perform maintenance such as confirming that

[0026]

EXAMPLES The basic idea of the present invention is as follows.

(1) The compressor adopts a scroll type with no reciprocating motion, is driven by detecting the operating suction pressure and changing the frequency of the inverter to control the rotation speed of the compressor, and has a dedicated machine room. To install.

(2) The liquid injection amount is controlled according to the temperature and pressure values of the gas discharged from the scroll compressor.
The position at which the refrigerant liquid is injected is the intermediate pressure portion of the scroll compressor.

(3) A failure such as an abnormal temperature rise in the inverter is judged, and if there is a failure, it is switched to a commercial power source.

(4) A mode in which the rotation speed is fixed and operation is performed is provided.

(5) As an operating state, at least the pressure and temperature of each part, the number of revolutions of the scroll compressor are digitally displayed, and in addition, the reason why the operation is stopped and the reason for the abnormal stop are displayed.

Specific embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing the overall arrangement of the store refrigeration system as seen from the installation relationship, and FIG. 2 is a side view of the same.
FIG. 3 is a block diagram showing the configuration of the refrigeration cycle unit viewed from the control relationship.

Reference numeral 2 provided in the store 1 indicates a chilled case in which items for sale are put, the temperature inside the refrigerator is kept at around 2 ° C., and 6 units with a width of about 1 m are installed.

In the back yard of the store, there is provided a walk-in case 3 in which goods can be put and customers can enter, and the temperature inside the store is maintained at about 5 ° C. In addition,
Connect at least three chilled cases 1,
In addition, it is desirable from the viewpoint of efficiency to operate the refrigeration system by performing sales activities for 2/3 or more of the day.

Reference numeral 4 denotes a machine room installed in the vicinity of the store, in which a scroll refrigerator 100 including a scroll compressor 10 and a drive device 200 for driving the scroll compressor 10 by inverter control is installed. Reference numeral 20 is an air-cooled condenser provided outdoors. Here, it is considered that the scroll compressor 10 which originally has a small torque fluctuation is further installed in the machine room 4 to prevent it from becoming a noise generation source and to facilitate maintenance.

In the refrigeration cycle section, the chilled case 2, walk-in case 3, accumulator 60, scroll compressor 10, air-cooled condenser 20, and liquid receiver 30 provided on the downstream side of the air-cooled condenser 20 are sequentially connected. In the liquid receiver 30, or the downstream side thereof and the compression working chamber (not shown) of the scroll compressor 10 are connected by a liquid injection pipe 85. Further, the liquid injection pipe 85 is provided with a flow rate control valve 80 for controlling the amount of liquid injection into the scroll compressor 10, and a solenoid valve 70 that is closed when the scroll compressor 10 is stopped and the power is shut off.

In the refrigerating apparatus and the refrigerating cycle unit configured as described above, the low-temperature low-pressure refrigerant gas evaporated in the chilled case 2 and the walk-in case 3 is stored in the accumulator 60 provided in the machine room 4. After passing, the scroll compressor 10 compresses the high-temperature high-pressure refrigerant gas. At this time, the pulsation of the high-pressure gas discharged from the scroll compressor 10 is small, and the flow noise of the refrigerant gas generated in the pipe and the vibration of the pipe itself can be reduced. Subsequently, the refrigerant gas is condensed into a refrigerant liquid in the air-cooled condenser 20 provided outdoors, and is temporarily stocked in the liquid receiver 30. And
After that, through the refrigerant liquid pipe 33, the chilled case 2 and the walk-in case 3, which are evaporators, enter the chilled case 2 and the walk-in case 3 again via the electromagnetic on-off valve 35 and the expansion valve 36 to form a cycle system, which emits cool air.

Next, the outline of the control operation of the suction pressure of the refrigeration cycle section of FIG. 3 will be described with reference to the flowchart of FIG.
When the capacity of the compressor is fixed, if the load required by the evaporator increases, that is, if the temperature rises in the chilled case 2 and the walk-in case 3, the suction pressure during operation of the compressor increases, On the contrary, when the load is reduced due to supercooling, the suction pressure becomes low. Therefore, by detecting this suction pressure and changing the rotation speed of the compressor, it becomes possible to perform capacity control operation in which the cooling capacity of the refrigerator is changed according to the load.

The operating suction pressure detected by the suction pressure sensor 91 is input to the controller 201 (step 4
01), the preset pressure value (Psb) and the preset pressure difference (ΔPs) are compared with each other with an allowable range (step 403). Inverter 2 to increase the frequency
A command for operating frequency is issued to 02 (step 405). However, the upper limit of the frequency is set to 80 Hz (step 4
04, 406). Then, the inverter 202 makes a power source of a frequency instructed by the controller 201, supplies it to the scroll compressor 10, and controls it so that the rotation speed increases.

On the contrary, the preset pressure value (Ps
If b) or less, that is, if it is in the (C) zone, the operating frequency is lowered (step 409). However, the lower limit of the frequency is set to 20 Hz (steps 408, 4).
06). If the operating suction pressure is within the allowable range, that is, if the zone (B) exists, the frequency at that time is maintained (step 406). The preset pressure value (Ps
b) and the set pressure difference (ΔPs) are the chilled case 2 at that time.
And, the temperature in the store where the walk-in case 3 is installed, the temperature outside the air-cooled condenser 20 is detected, and the temperature is automatically changed, whereby the environment changes for one year. Enables stable and efficient control.

Next, the temperature control of the discharge gas of the refrigeration cycle section of FIG. 3 will be described. Since the refrigerator equipped with the scroll compressor 10 holds oil on the discharge side, it is necessary to overheat to some extent in order to maintain the viscosity of the oil, and if the discharge pressure is constant, Only the temperature of the discharged gas needs to be controlled. However, since the discharge pressure changes depending on the operation suction pressure, the operation frequency, and the outside air temperature, it is necessary to control the temperature as low as possible without overheating even in such a case. Therefore, the controller 201 calculates the degree of superheat of the refrigerant, which is determined by the relationship between the temperature of the discharge gas detected by the discharge gas thermistor (temperature detector) and the pressure detected by the high pressure sensor 92. Then, the opening degree of the flow rate control valve 80 is changed based on the degree of superheat to control the amount of the refrigerant liquid injected to the scroll compressor 10 (the liquid injection amount), so that the liquid injection is performed in the case of overheating. By increasing the amount, the temperature of the discharge gas is lowered without reducing the refrigerating capacity, and the temperature is constantly controlled to an appropriate temperature. From this, it is possible to use the CFCs 22 other than the CFCs without using the CFCs as the refrigerant.

FIG. 8 is a view relating to the fine hole positions of the scroll wrap for injecting (injecting) the refrigerant liquid into the scroll compressor 10, and the refrigerant liquid injection holes 141
a and 141b are provided at a position within one roll from the winding start end of the scroll wrap and along the side wall of the end plate of the fixed scroll wrap. By setting this position, the refrigerant liquid will be injected into the intermediate pressure portion,
Excessive liquid compression of the refrigerant can be avoided and reduction in refrigeration capacity can be avoided.

Similarly, by calculating the degree of superheat of the intake gas, which is determined by the relationship between the temperature of the intake gas detected by the intake gas thermistor 93 and the operating intake pressure, it is possible to prevent wet compression and to give an alarm. can do.

As described above, the degree of superheat on the discharge side and the degree of superheat on the suction side are determined by the pressure and temperature when the type of the refrigerant is determined, but the superheat degree is different even at the same temperature and pressure when the type of the refrigerant is different. For this reason, the physical properties of several types of refrigerants are previously entered in the controller 201 so that the correct degree of superheat can be calculated even if the types of refrigerants are different, and these values can be selected by a setter such as an external switch. deep. As a result, it is possible to correctly control the degree of superheat even when the type of refrigerant is different.

A method of continuing the operation even if the inverter fails will be described with reference to FIG.

When the inverter 202 is normal, the electromagnetic contactor 203 and the electromagnetic contactor 204 are closed, and the power is supplied to the electric motor for the scroll compressor 10 for control. Inverter 202 When the temperature rises abnormally Inverter 202
The controller 201 outputs an abnormal signal from itself to the controller 201, and the current is detected by the current detector 201 provided on the secondary side of the inverter 202.
Current detector 20 despite issuing an operation command to
When the current is not detected in 1 or the like, it is determined that there is a failure, the electromagnetic contactor 203 and the electromagnetic contactor 204 are opened, the electromagnetic contactor 205 is closed, and the commercial power source is directly used as an electric motor for the scroll compressor 10. It is energized. As a result, at least the operation will not be stopped even if the operation is not controlled.

FIG. 6 shows the periphery of the scroll compressor in the refrigeration system 100. The refrigeration system 100 includes an inverter 202, a controller 201, and an electromagnetic contactor 20.
A digital display panel 207 is provided in an electrical equipment box 200 including 3, 204, 205, a current detector 206, and the like. FIG. 7 shows details of the digital display panel 207,
Code 208 and data 20 are digitally displayed items.
9 and a display item selection key 210 are provided. By operating the selection key 210, operating states (set pressure, discharge pressure, suction pressure, etc., discharge gas temperature, suction gas temperature, store temperature, outdoor temperature, etc., discharge gas refrigerant superheat degree, suction Each superheat degree such as the superheat degree of the gas refrigerant and other operating frequencies, operating currents, etc.) are numerically displayed in the data 209. When an abnormal state occurs, the abnormal lamp 211 is turned on, and the operation at the time of the abnormal stop is performed so that the operator can know which protective device has been activated when the stop reason code at that time and the protective device is activated. It has the function of holding the state.

[0049]

According to the present invention, when a plurality of small refrigerated showcases are installed, even if the number of connected showcases and the storage temperature change significantly due to remodeling in the store and changes in the displayed items, the load is reduced. Depending on the capacity, it is possible to operate according to the capacity, and the suction pressure during operation of the refrigerator is always constant throughout the year, thus achieving an energy saving effect. Further, the temperature fluctuation in the showcase can be finely controlled so as to be minimized, the storage temperature in the showcase is stable, and the freshness of the stored goods can be improved. Furthermore, by placing a scroll compressor that originally has little torque fluctuation in the machine room, it is possible to realize low noise and space saving, and to obtain a refrigerating device for stores that is also advantageous for trial operation, service, response to failure and display etc. You can

[Brief description of drawings]

FIG. 1 is a plan view showing the overall arrangement of an embodiment of a store refrigeration system of the present invention.

FIG. 2 is a side view showing the overall arrangement of the embodiment.

FIG. 3 is a block diagram showing a configuration of a refrigeration cycle unit of one embodiment.

FIG. 4 is a flowchart showing an outline of a suction pressure control operation of the refrigeration cycle unit according to the embodiment.

FIG. 5 is a block diagram illustrating a method of continuing operation when an inverter fails in one embodiment.

FIG. 6 is a side view showing peripheral devices of the scroll compressor according to the embodiment.

FIG. 7 is a front view showing details of a display panel according to an embodiment.

FIG. 8 is a cross-sectional view showing the meshing state of the scroll wraps inside the scroll compressor of one embodiment and the relationship between the scroll wraps for injecting (injecting) the refrigerant liquid and the fine hole positions.

[Explanation of symbols]

1 ... Store, 2 ... Chilled case (showcase), 3 ... Walk-in case (showcase), 100 ... Scroll refrigerator, 4 ... Machine room, 10 ... Scroll compressor, 91
... Intake pressure sensor, 202 ... Inverter, 201 ... Controller, 33 ... Piping, 20 ... Air-cooled condenser, 30 ... Liquid receiver, 60 ... Accumulator, 85 ... Liquid injection piping, 80 ... Flow control valve, 92 ... High pressure Sensor, 9
3 ... Intake gas temperature thermistor, 94 ... Discharge gas thermistor, 5 ... Electromagnetic on-off valve, 36 ... Expansion valve, 203, 204,
205 ... Electromagnetic contactor, 207 ... Digital display panel, 2
08 ... Code, 209 ... Data, 210 ... Selection key, 1
41a, 141b ... Pore for injection.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoaki Miya 390 Muramatsu, Shimizu City, Shizuoka Prefecture Hitachi Ltd. Air Conditioning Systems Division

Claims (13)

[Claims] 1. At least three or more chilled cases provided in a store for keeping the inside temperature at about 2 ° C., and walks provided on the backyard of the store for keeping the inside temperature at about 5 ° C. An in-case, a scroll compressor provided in a closely arranged machine room and a drive device for driving the scroll compressor by inverter control, and a heat exchanger provided outdoors.
The chilled case, walk-in case, a scroll compressor and a pipe that constitutes a refrigeration cycle by sequentially connecting the outdoor heat exchanger, a receiver provided on the downstream side of the refrigeration cycle outdoor heat exchanger, and the liquid receiver A liquid injection pipe connecting the inside of the device or the downstream side thereof to the compression working chamber of the scroll compressor, a flow control valve for controlling the liquid injection amount provided in the liquid injection pipe, and a discharge gas of the scroll compressor. A refrigerating apparatus for stores, comprising: a controller that controls the control valve according to the temperature of 1), and an on-off valve that is provided in each pipe that guides the refrigerant to each of the chilled cases. 2. The refrigerating apparatus for a store according to claim 1, wherein the store is a store that conducts sales activities for 2/3 or more of a day. 3. A refrigerating apparatus for stores according to claim 1, wherein the controller controls a flow rate control valve so that a refrigerant superheat degree downstream of the compressor becomes constant. 4. The store according to claim 1, wherein one end of the liquid injection pipe is opened so as to communicate with the compression working chamber at a position within one wrap from the discharge port of the scroll compressor. Refrigeration equipment. 5. The refrigerating apparatus for stores according to claim 1, wherein the chilled case has a width of 3 and five or more units are connected to one refrigeration cycle unit. 6. The compressor according to claim 1, wherein the compressor is an inverter.
The refrigeration system for stores, wherein the drive device driven by the computer control has means for judging an inverter failure and automatically switching to a commercial power source to continue the operation. 7. The drive device for the scroll compressor according to claim 1, further comprising means for controlling a rotational speed according to suction pressure, and means for operating at a fixed rotational speed. Refrigeration equipment for stores. 8. The refrigeration system for a store according to claim 1, further comprising means for digitally displaying an operating state (each pressure, temperature, degree of superheat, number of revolutions) of the refrigeration system, a reason for stopping, and a reason for abnormal stopping. apparatus. 9. A chilled case of at least 3 units in which the temperature inside the store is kept at around 2 ° C., and the temperature inside the store is 5 ° C.
In a refrigeration system provided with a walk-in case that is held in the front and rear, a scroll compressor provided in a machine room installed indoors close to the store, and provided on the suction side of the scroll compressor, A suction pressure sensor for detecting suction pressure, a means for controlling the number of revolutions of the scroll compressor by changing the frequency of the inverter according to the value of the suction pressure sensor, and an outdoor unit provided for the chilled case, walk-in case, scroll compression Refrigerating cycle unit consisting of a cooling machine and an air-cooled condenser connected by sequential piping, a liquid receiver provided on the downstream side of the air-cooled condenser of the refrigerating cycle unit, and in the liquid receiver or A liquid injection pipe connecting the downstream side to a compression working chamber of the scroll compressor, and a liquid injection pipe provided in the liquid injection pipe. A flow control valve for controlling the injection amount, a discharge gas thermistor for detecting the temperature of the discharge gas of the scroll compressor, a high pressure sensor for detecting the pressure on the discharge side of the scroll compressor, and the discharge gas thermistor. Refrigeration for stores, characterized in that it comprises means for controlling the opening of the flow rate control valve based on the value of the high pressure sensor, and electromagnetic on-off valves provided in respective pipes for guiding the refrigerant to the chilled cases. apparatus. 10. The refrigerating apparatus for stores according to claim 9, wherein the chilled case has a width of about 1 m and is connected to the refrigerating cycle unit by five or more units. 11. The means for judging a failure of the inverter according to claim 9, and when the judgment means judges a failure, the power source of the scroll compressor is switched to a commercial power source to continue the operation. A refrigerating apparatus for stores, which is provided with: 12. The operation system according to claim 9, further comprising means for digitally displaying at least the pressure and temperature of each part and the rotation speed of the scroll compressor as an operating state, and means for displaying the reason for stoppage and the reason for abnormal stoppage. Refrigeration equipment for stores. 13. A refrigerator main body provided in a machine room, a scroll compressor whose rotation speed is controlled by an inverter and whose liquid injection amount is controlled, at least three or more chilled cases, and a walk-in case. A refrigerating apparatus for stores having a pipe for guiding a refrigerant to the chilled case and an opening / closing valve for detachably attaching the chilled case to the pipe.