JPH0220917B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operation control system for a refrigerated warehouse equipped with a plurality of refrigeration units.

The refrigerated warehouse industry is involved in the storage and storage of goods with low added value, and reducing electricity costs is essential to improving business profits.

On the other hand, in recent cold storage warehouses, many decentralized (unit type) refrigerators have been adopted after the legal reform in 1975. Such refrigerators may operate at full speed for cooling, and the contracted power must be considered at the maximum installed capacity, which increases the contracted power.

Furthermore, past data shows that the operating state of the refrigerator after it enters a steady state is sufficiently covered by the amount of electricity used, which is about 40 to 60% of the contracted electricity.

The purpose of the present invention is to efficiently control the number of multiple refrigeration units used in refrigerated warehouses in consideration of the above points, to suppress maximum power consumption, and to reduce costs by reducing basic electricity charges. .

However, according to the present invention, the purpose of this lever is to first search for the internal temperature in a refrigerated warehouse equipped with a plurality of refrigeration units, and to start the compressor of each refrigeration unit if it is above the set temperature upper limit. Then, compare the actual total current consumption of all compressors with the total current peak setting value, and if the former is higher, search for the internal temperature individually again, and if it is between the upper and lower set temperature limits. This is achieved by individually unloading the compressors in the refrigerator that are close to the lower limit value.

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

Fig. 1 is a cross-sectional plan view of a refrigerated warehouse using the operation control system of the present invention, and Fig. 2 is a longitudinal sectional front view of the same. , this duct 2 is connected to a cooler 3, and the cooler 3 is connected to a condensing unit 4 including a compressor 10, which will be described later, placed outdoors.

A temperature detector 5 is installed in each room, and a refrigerator monitoring panel 6 and a power saving system panel 7 are installed outdoors on the first floor.

FIG. 3 shows a block circuit diagram showing an embodiment of the present invention, in which a comparison circuit 8 compares the detection signal A of the temperature detector 5 with the set temperature signal B which determines the normal refrigeration temperature.
to be introduced.

This comparison circuit 8 compares the detection signal A and the set temperature signal B, and outputs signals when the value of the signal A is larger than the upper limit value of the signal B and when the value of the signal A is close to the lower limit value of the signal B. A circuit that emits a signal.
The output signal C of the comparison circuit 8 is introduced into a compressor drive circuit 9, and the drive signal D from the same circuit 9 is introduced into the compressor 10.

Further, the abnormality detection signal E from the comparison circuit 8 is introduced into the alarm device 11. This alarm device 11 uses a buzzer or the like, but the detection signal A' from the temperature detector 5 is introduced into the detection circuit 18, and the compressor failure signal J from the detection circuit 18 that receives this is also introduced into the alarm device 11. .

On the other hand, the power detection signal F of the power consumption detector 12 consisting of a current transformer etc. provided in the energizing circuit to the compressor 10
A set power consumption signal G determined from empirical rules is introduced into the comparison circuit 13.

The comparison circuit 13 is a circuit that compares the values of the signal F and the signal G and issues an output signal when the former is larger.The output signal H of the comparison circuit 13 is introduced into the compressor drive circuit 9.

FIG. 5 is an explanatory diagram of the 3 parts of the cooler 3 of the present invention.
5, 16 are installed, and these measuring devices 15, 16 are connected to the converter 17, and the defrost signal I of the converter 17 is
is introduced into the compressor drive circuit 9.

This converter 17 includes an arithmetic comparison circuit and emits an output signal I when the difference in wind pressure between the measuring devices 15 and 16 exceeds a certain value.

Next, how to use it will be explained.

Figures 4a-4c show a flowchart of the present invention. First, when starting, set the total current consumption peak set value I ₀ and the upper and lower limits of the internal temperature. In this case, if the set temperature of the lower limit value is T, the upper limit value T _S is 5
The temperature will be about ℃ higher.

Then, the temperature detector 5 first searches for the temperature inside each of the multiple refrigerators, and when this temperature T _N is higher than the normally required upper limit value T _S of the set temperature, the comparison circuit 8 An output signal C for instructing the compressor of the refrigerator to start is introduced into the compressor drive circuit 9, and the circuit 9 receives this signal C and outputs the drive signal D.
2. Start the compressor 10 of the refrigerator. The search for the temperature inside the refrigerator is performed sequentially for each floor or compartmented refrigerator as shown in Figure 2 _.
Steps that satisfy the condition ≦T _N proceed to the next step.

When the compressor 10 starts, the power detector 12
detects the current consumption of each compressor 10 and introduces the current detection signal F to the comparison circuit 13.

The comparison circuit 13 synthesizes the detected values of each detector 12 to obtain the power facility total current consumption, compares this value I ₁ with a preset power facility total current consumption peak set value I ₀ , and calculates I When ₀ < I ₁ , the temperature detector 5 is activated and the temperature inside each refrigerator is measured again.

In this way, the temperature inside each refrigerator is detected, and the temperature is increased by a certain amount (for example, T _S +3) above the set temperature upper limit T _S.
℃), it is determined that the temperature is abnormal and is output to the alarm device 11 to issue an abnormal temperature alarm inside the refrigerator.

On the other hand, when going to the above step, the temperature inside the refrigerator is all T _S.
+Registered refrigerator internal temperature T ₁ ″℃~, provided that it is not higher than a certain temperature (3℃)
Search for the one closest to the lower limit T among T _N ″°C.

On the other hand, if this searched temperature is lower than the upper limit of the set temperature, then search again for the internal temperature.
_TN is compared with the set lower limit value T, and if the same or the searched chamber temperature is smaller than the set lower limit value (T _N ″≦T), the compressor 10 is stopped.

Next, if the search temperature is not equal to the lower limit value, it is determined whether or not the compressor 10 is in load operation, and if it is not in load operation, the compressor 10 is
If the load operation is stopped, the compressor drive circuit 9
In this case, a drive signal D containing an unloading operation command is introduced into the compressor 10, and the compressor 10 is operated in an unloading operation.

In this way, it is displayed that the compressor 10 is being operated in unload mode.

As mentioned above, the compressor 10 has a set upper and lower limit for the internal temperature and the actual total current consumption I ₁
is greater than the set peak value _I0 , and unloading is performed from the compressor 10 whose internal temperature is close to the set lower limit value, that is, where the need for cooling is low. To go.

Then, until all the compressors 10 are in unloading operation, the total current consumption I ₁ ' and the set peak value are compared each time, and under the condition of I ₀ to I ₁ ', the compressors that are already in unloading operation are compared. Among the internal temperatures of the refrigerators other than the one in charge, a search is made for one that is close to the set lower limit value, and the process returns to Step 3 to repeat the steps.

On the other hand, if the total current consumption I ₁ ″ still exceeds the current peak set value I ₀ even after all compressors 10 are unloaded, (this detection is scanned a certain number of times), the peak cut When the failure display alarm is issued, the manager looks at the temperature indicator in each warehouse and manually stops the compressors that are not causing any problems.

A possible cause of such a peak cut state is that when a large amount of room-temperature cargo is transported to a refrigerator, the cooling capacity is sufficient and no unloading operation is required.

The reason why the machines are stopped manually instead of automatically and uniformly is because stopping is selected depending on the importance of the load.

Also, the actual total current consumption in the stepper
If I ₁ ′ is not greater than the current peak set value I ₀ , then
Search for the internal temperature of each refrigerator, and then find the one whose internal temperature is closest to the set temperature upper limit T _S. This is the procedure to end the unloading operation, and it is determined whether the compressor of the detected refrigerator is in the unloading operation or not, and if it is in the unloading operation, the compressor is instructed to start the loading operation. do. In this way, I ₀ in temperature search again
<T ₁ (search temperature), other than the compressor that was changed from unload operation to load operation, the next one that is close to the set temperature upper limit is given a load command, and finally all compressors 10 Repeat until the load operation is started.

By the way, if the compressor does not start even if there is a command to start the compressor in StepPro, it will search for the internal temperature of the refrigerator and find out by scanning several times that the internal temperature is higher than the upper limit of the set temperature. If detected, it is determined that the compressor 10 is at fault and a compressor operation abnormality alarm is displayed.

Also, in the above step, the actual total current consumption I ₁
is not greater than the peak set value I ₀ , the temperature inside each refrigerator is searched, and if that temperature is equal to or lower than the lower limit of the set temperature, the corresponding compressor is determined to be sufficiently cooled inside the refrigerator. Stop. On the other hand, if the internal temperature is higher, the compressor continues to sequentially search for the internal temperature of the refrigerator in operation.

On the other hand, if the searched temperature is not lower than the set upper limit, the step search searches for the internal temperature of the refrigerator closest to the set temperature lower limit and then the next closest refrigerator, and repeats this process until all internal temperatures are reached. If the upper limit is exceeded, proceed to the procedure when peak cutting is impossible.

FIG. 6 shows a flowchart when defrosting operation is performed in the middle of the above operation control, and when the wind pressure of the cooler coil is monitored and the differential pressure between wind pressure measuring devices 15 and 16 reaches a certain value or more, defrosting is started. As a command, converter 17 sends a defrost signal I to compressor drive circuit 9, circuit 9 sends an output signal D containing an off signal to compressor 10, and compressor 10 is stopped.

In this state, defrost is started and hot gas or hot water is sprayed on the cooling coil 3a, and when the frost melts, the differential pressure between the wind pressure measuring devices 15 and 16 decreases, and as a result, the defrost signal I from the converter 17 as a defrost completion command also disappears. Compressor 10 is started again.

At this time, the temperature inside the refrigerator is measured by the temperature detector 5, and the operation is then controlled according to the procedure shown in FIG.

As described above, the operation control system for a refrigerated warehouse according to the present invention efficiently performs cooling, and then selects a compressor that requires less cooling and performs unloading operation, thereby eliminating the waste of energy previously used. It is possible to reduce power consumption by approximately 40% to 60%, resulting in cost reductions.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional plan view of a refrigerated warehouse using the operation control method of the present invention, and FIG. 2 is a vertical cross-sectional front view of the same.
FIG. 3 is a block circuit diagram showing an embodiment of the present invention;
4a, 4b, and 4c are flowcharts, FIG. 5 is an explanatory diagram of the cooler portion, and FIG. 6 is a flowchart of defrost operation. 1... Refrigerated warehouse, 2... Duct, 3... Cooler, 3a... Cooling coil, 4... Condensing unit, 5... Temperature detector, 6... Freezer monitoring panel, 7... Power saving System board, 8...comparison circuit,
9... Compressor drive circuit, 10... Compressor, 11...
... Alarm device, 12 ... Power detector, 13 ... Comparison circuit, 15, 16 ... Wind pressure measuring device, 17 ... Converter, 18 ... Detection circuit.

Claims (1)

[Claims] 1 In a refrigerated warehouse equipped with multiple refrigeration units, the temperature inside the warehouse is first searched, and if it is above the set temperature upper limit, the compressor of each refrigeration unit is started, and then the actual total consumption of all compressors is Compare the current and the total current peak set value, and if the former is higher, search for the temperature inside the refrigerator individually again, and if it is between the upper and lower set temperature limits, check the compression in the refrigerator near the lower limit. An operation control system for a frozen and refrigerated warehouse that is characterized by unloading the containers one by one.