JPH0830621B2 - Device for controlling the number of operating air-cooled refrigerators - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention supplies heat energy to a load using a plurality of air-cooled refrigerators such as an air-cooled turbo, an air-cooled chiller, and an air-cooled heat pump chiller. The present invention relates to a controller for controlling the number of operating air-cooled refrigerators.

[Conventional technology]

During air conditioning of an office building, a plurality of air-cooled refrigerators, for example, a heat pump type chiller (cooler / heater) and a forward or return path between a heat exchanger serving as a cooling or heating load are connected via a header, A method is known in which the number of operating chillers is controlled according to the heat quantity of the load or the outlet temperature and the inlet temperature of the header viewed from the load side.

FIG. 4 is a configuration diagram of a conventional operating unit number control system using three air-cooled heat pump chillers.

In the figure, 1 is a first air-cooled heat pump chiller (hereinafter, simply referred to as “first chiller”), 2 is a cold / hot water circulating pump that functions as an auxiliary of the first chiller 1, and 3 is a second air-cooled heat pump chiller (hereinafter, simply referred to as “chiller”). (2nd chiller), 4 is a cold / hot water circulation pump that functions as an auxiliary to the second chiller 1, 5 is a third air-cooled heat pump chiller (hereinafter simply referred to as a third chiller), and 6 is an auxiliary to the third chiller 5. It is a hot and cold water circulation pump.

The outlet sides of the first to third chillers 1, 3 and 5 are connected in parallel to the outflow header 10 via pipes 7 to 9, and the suction sides of the pumps 2, 4 and 6 are pipes 11 to 11. Return water header through 13 14
Are connected in parallel. Reference numeral 15 is a bypass valve connected between the outgoing water header 10 and the returning water header 14 to secure the minimum amount of water in the chiller.

Reference numeral 16 denotes a cooling or heating load (heat exchanger) connected between the outgoing water header 10 and the returning water header 14 via pipes 17 and 18 and a two-way valve 19. A hot water sensor 20 for detecting the outlet outgoing water temperature from the water header 10 is provided,
The pipe 18 is provided with a temperature sensor 21 for detecting the return water inlet temperature to the return water header 14, and the pipe 18 is provided with a flow meter 22 for detecting the flow rate of cold and hot water flowing through the load 16.
Is provided.

The outgoing water temperature sensor 20, the returning water temperature sensor 21 and the flow meter
The detection signal of 22 is taken in by the control unit 23, and from the control unit 23, the first to third chillers 1, 3, 5
A start / stop signal is supplied to the pumps 2, 4, and 6.

In the conventional chiller operation control device configured as described above, when the detection signal detected by each of the outgoing water temperature sensor 20, the return water temperature sensor 21, and the flow meter 22 is taken in by the control unit 23, the control unit 23 Then, (going water temperature-return water temperature) ×
The calculation of the flow rate is executed to obtain the load heat quantity, and the number of operating chillers is determined according to the load heat quantity.

That is, in the case where three chillers are designed to cover the maximum heat quantity of the load 16, when the currently requested heat quantity of the load 16 is within 33% of the total, for example, the first chiller 1 and its pump 2 An operation command is given from the control unit 23 to these to operate them. At this time, the capacity of the first chiller 1 is controlled by a built-in capacity control means (not shown) so as to reach a predetermined temperature set value.

When the heat quantity of the load 16 exceeds the rated capacity of one chiller, the controller 23 gives an operation command to the second chiller 3 and the pump 4, for example. Furthermore,
When the control unit 23 determines that the load heat amount exceeds the value (66% of the total heat amount) of both rated capacities of the operation of the first chiller 1 and the second chiller 3, the third chiller The operation command is also given to 5, and the three chillers are operated together.

The relationship between the load and the number of chillers at this time is as shown by the solid line in FIG. The broken line in FIG. 5 represents the state when the load heat quantity is reduced.

[Problems to be Solved by the Invention]

The conventional chiller number control device as described above calculates the load heat quantity on the secondary side from the outgoing water temperature and the return water temperature and the flow rate flowing through the load, and determines the operating number of chillers based on the calculation result. Therefore, there is no problem if the chiller is installed in a place where the environment is relatively stable, such as in an indoor laboratory, but this type of chiller is generally installed in a building with a strong airflow such as on the roof of a building. Because most are
A part of the high temperature air blown out from the chiller is returned to the chiller's inlet, so-called short circuit etc. occurs, and the installed environment may not be able to demonstrate the designed capacity, and the control of the number of operating chillers may be hindered. May come.

That is, when a short circuit or the like occurs in the chiller, the chiller itself is capacity-controlled so that the incoming water temperature becomes the set temperature, so the operating pressure of the chiller compressor increases during cooling, and the work amount of the compressor increases accordingly. That is, the power also rises. At this time, if the temperature of the air sucked into the chiller's suction port is within the design temperature (eg 35 ° C) that can be covered by the chiller's rated capacity, there is no problem, but the temperature of the chiller's suction air due to the short circuit is, for example, 40
Above ℃, the coefficient of performance of the chiller, And the power of the chiller is overloaded with the rated value exceeded. However, the overload condition and the decrease in the coefficient of performance cannot be judged by the conventional method of monitoring the heat quantity of the secondary load, and the inefficient operation of the chiller due to this cannot be checked.

Also, because the capacity control installation of each chiller varies, for example, two chillers are operated depending on the load heat amount,
And one chiller operates 100%, the other chiller 0-5
Even in the unbalanced operation state where 0% ON-OFF operation is performed, this state cannot be grasped, and as a result, the life cycle cost of the chiller that operates 100% increases, and it lacks energy saving. There was a problem that the optimal number control was not sufficient.

An object of the present invention is to solve the above problems and to provide an operating number control device for a heat pump chiller that is energy-saving and that enables optimal number control in consideration of reduction in life cycle cost.

[Means for solving the problem]

The operating number control device of the air-cooled refrigerator of the present invention, a plurality of air-cooled refrigerators connected in parallel to the load via the outgoing and return water header, the inlet and outlet cold water temperature of each air-cooled refrigerator. A temperature sensor for detecting, a flow meter for detecting the flow rate of cold water flowing through each of the air-cooled refrigerators, a power meter for detecting the amount of electric power of each of the air-cooled refrigerators, the temperature sensor, each of the flow meters and each of the electric powers. The load of each operating air cooling type refrigerator, the coefficient of performance of each operating air cooling type refrigerator, and the power consumption of each operating air cooling type refrigerator are calculated based on the detection signal detected by the meter, and the air cooling type refrigerator is calculated from the calculation result. And a control unit that determines the appropriate number of operating units of the refrigerator, and in the control unit, the operating number of the refrigerators is calculated by multiplying the flow rate of each refrigerator by the inlet / outlet temperature difference of each refrigerator to obtain the load value of each refrigerator. And the power consumption of each refrigerator is rated at the same time. Determining the increased one when the upper, is characterized in that the power consumption of 50% or less of the refrigerator to determine decrease one if there are multiple base. Things.

[Action]

In the present invention, the load, power consumption, and coefficient of performance of the operating chiller are calculated by incorporating the detection signals detected by the temperature sensor, the flow meter, and the power meter of the air-cooled refrigerator during operation into the control unit. The optimum number of operating chillers is determined by performing chiller overload determination, low load operation determination, and chiller performance coefficient determination based on the calculation results, so it is possible to control the optimal number of chillers with consideration of energy saving and life cycle cost reduction. become.

〔Example〕

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

FIG. 1 is a configuration diagram showing an embodiment in which the operating number control device for an air-cooled refrigerator according to the present invention is applied to three air-cooled heat pump chillers (cooling / heating machines).

In the figure, the same parts as those of the conventional example shown in FIG. 4 are denoted by the same reference numerals, detailed description thereof will be omitted, and parts different from those of FIG. 4 will be mainly described.

That is, the pipe 7 that connects the first chiller 1 to the outgoing header 10
Temperature sensor 24 for detecting the outlet temperature of the first chiller 1
The pipe 11 connecting the suction side of the cold / hot water pump 2 of the first chiller 1 and the return water header 14 is provided with a temperature sensor 25 for detecting the return water inlet temperature and a return water flow rate to the first chiller 1. A flow meter 26 for detecting is provided, and a power meter 27 for detecting the power consumed by the compressor of the first chiller 1 is further provided.

Also, in the pipe 8 to the outgoing header 10 of the second chiller 3,
A temperature sensor 28 for detecting the outgoing water outlet temperature of the second chiller 2 is provided, and the pipe 12 connecting between the suction side of the cold / hot water pump 4 of the second chiller 3 and the return water header 14 is provided with the second chiller 3. A temperature sensor 29 for detecting the return water inlet temperature to the second chiller 3 and a flow meter 30 for detecting the return water flow rate to the second chiller 3,
Furthermore, a power meter 31 for detecting the power consumed by the compressor of the second chiller 3 is provided.

In the same way, the piping 9 to the outflow header 10 of the third chiller 5
Is provided with a temperature sensor 32 for detecting the outgoing water outlet temperature of the third chiller 5, and the cold / hot water pump 6 of the third chiller 5 is provided.
In the pipe 13 connecting the intake side of the return water and the return water header 14, the temperature sensor 33 for detecting the return water inlet temperature to the third chiller 5 and the third
A flow meter 34 for detecting the flow rate of return water to the chiller 5 is provided, and further, a power meter 35 for detecting the power consumed by the compressor of the third chiller 5 is provided.

The detection signals of the temperature sensors 24, 25, 28, 29, 32, 33, the detection signals of the flow meters 26, 30, 34 and the detection signals of the power meters 27, 31, 35 are input to the control unit 36. The control section 36 starts / stops the first chiller 1 and its cold / hot water pump 2, the second chiller 3 and its cold / hot water pump 4, the third chiller 5 and its cold / hot water pump 6. The signal is designed to be output.

The control unit 36 takes in the outlet and inlet temperatures of each chiller during operation, the flow rate, and the detected power value, and thereby the load of each chiller (heat amount = flow rate of each chiller x temperature difference between inlet and outlet of each chiller), power consumption And calculating the coefficient of performance COP,
Based on these calculation results, the optimum number of operating chillers for the load 16 is determined, and the central processing unit (hereinafter referred to as CPU) 36a that controls the whole, the load (heat amount), the power consumption amount, and the coefficient of performance COP ROM 36b for storing a program for arithmetic processing, a program for determining the number of operating vehicles based on the arithmetic result, and set value data for overload determination of the operating chiller, and temporarily storing the arithmetic result and various detection data in the CPU 36a It is composed of a RAM 36c, an input interface 36d for inputting detection signals of a temperature sensor, a flow meter and a power meter to the CPU 36a, and an output interface 36e for sending a start / stop signal to a chiller and its cold / hot water pump. It is connected to the CPU 36a via the bus 36f.

Next, the operation of the present embodiment configured as described above will be
This will be described with reference to the flowchart shown in the figure.

When the program shown in FIG. 2 is started in controlling the number of chillers with respect to the load heat quantity, first, in step S1, the input interface 36d side is scanned to detect the inlet / outlet temperature sensors 24, 25 of the chillers 1, 3, 5. , 2
The detection signals of the 8,29,32,33, the flow meters 26,30,34 and the power meters 27,31,35 are fetched into the CPU 36a and stored in the RAM 36c. Then, in the next step S2, the number of operating chillers is checked from the captured detection data, and in the next step S3, it is determined whether or not all the chillers are stopped. Here, when it is determined that all the units are stopped, the flow of FIG. 2 ends. If it is determined that all the vehicles are not stopped, the process proceeds to step S4, the load (heat amount) of the operating chiller is calculated from the respective inlet / outlet temperature and flow rate, and this is stored in a predetermined memory area of the RAM 36c. After that, the process proceeds to step S5, the amount of power consumed by the compressor of the operating chiller is calculated, and this is stored in a predetermined memory area of the RAM 36c. In the next step S6, step S4
Also, the coefficient of performance COP of the operating chiller is calculated based on the load (output heat amount) and power consumption calculated in S5.

In the next step S7, it is determined whether or not the number of operating chillers for the load 16 including the power consumption of the operating chiller and the coefficient of performance COP is within the appropriate load range. Here, out of the three chillers 1,3,5, two chillers 1,3 are operated and
It is assumed that the area is shaded as shown in FIG.
At this time, if it is determined in step S7 that the load range is appropriate, the process proceeds to step S8 to check whether all the vehicles are overloaded due to the short circuit of the driving chillers 1 and 3.
Judge by comparing the power consumption of each chiller 1 and 3 with the set value.

If it is determined that all the units are overloaded, that is, the power consumption of the two chillers 1 and 3 exceeds the set value as shown in FIG. 3 (b), the process proceeds to step S9. , Even if one of them is below the set COP. If "NO", the process returns to step S1, and if "YES", a process of increasing the operating number by one is performed even if it is determined that two units are appropriate at the stage of determining the number of units by the load heat quantity. That is, an operation command is given to the third chiller 5 and its cold / hot water pump 6 to operate the three chillers to prevent the COP setting of each chiller from decreasing. Here, the set COP is 50% of the rated power consumption in the first year.
Collecting actual measurement data at power consumption of 100%
It is a value calculated by calculating OP and setting COP = average value COP-standard deviation σ. However, the number of data shall be 50 or more.

When it is determined to be "NO" in step S8, the process proceeds to step S11, and it is determined whether or not the plurality of chillers are in the low load operation. Here, if it is determined that the two chillers 1 and 3 are not in the overload state and that they are not in the low load operation (50% or less of the rated capacity), the process returns to step S1. As shown in FIG. 3 (c), when it is determined that a low load operation is performed at 50% or less of the rated capacity, the process proceeds to step S12, and a process of reducing the operating number by one is executed. That is, one of the chillers 1 and 3 is forcibly stopped, and the capacity of the other operating chiller is controlled to the capacity when both chillers were operating.

When it is determined in step S7 that the load is not more than the appropriate load range, the process proceeds to step S13, and it is determined whether the statistics of the operating load ratios of all the chillers in operation are 150% or more. here,
When it is determined that the operating load ratios of all the chillers are 150% or more, it is determined that the variations in the operation among the chillers are severe, and the process proceeds to step S14 to request the setting change process of the main body thermostat. That is, due to variations in the capacity control set values of the compressors of the chillers 1 and 3, the power of one chiller 1 is operated 100%, and the other chiller 3 is turned on and off. Of the chillers 1 and 3 is requested so that the one-sided operation does not occur. Here, the operating load ratio means, for example, when one unit operates at 100% of rated power and the other unit operates at 30%, Is an index indicating the degree of variation.

Further, when it is determined in step S13 that it is 150% or less, the process proceeds to step S15, and it is determined whether or not the plurality of chillers are in the low load operation. Here, two chillers 1,3
When it is determined that both are operating at 50% or less of the rated power, the process proceeds to step S16, one of the operating chillers is forcibly stopped, and one unit is operated. When it is determined that the chillers 1 and 3 are not in the low load operation, the process returns to step S1.

On the other hand, if it is determined in step S7 that the load range is equal to or more than the appropriate load range, the process proceeds to step S17, in which the operation chillers 1, 3
Even if one of the above is operating at rated power or more, it is judged whether it is overloaded. If "NO" is determined here, the process returns to step S1. If "YES" is determined, the process proceeds to step S18, and it is determined whether or not one unit is equal to or less than the set COP. Here, if it is determined that it is not less than or equal to the set COP, step S1
If the power consumption of the overloaded chiller is below the set COP, that is, if the power consumption of the overloaded chiller is above the rating, and if its capacity is below the rating, go to step S19 and increase the operating number by one. Perform the process to That is,
Operate the third chiller 5 of the third unit.

In the present embodiment as described above, when the chiller is operated by the appropriate operating number determined for the required heat quantity of the load 16, the chiller repeats ON-OFF operation (50% or less of the rated capacity). In such a low load operation, even if the load is determined to be two, one of them is
The table is forcibly stopped, and more appropriate table control suitable for the load 16 is possible.

In addition, when the appropriate number of chillers is determined according to the load 16 and the determined number of chillers are operating, when the chiller power consumption exceeds the rated value and the overload condition occurs, this is judged and the number of operating chillers is determined. Therefore, there is no problem that the chiller continues to be driven with the coefficient of performance being lowered due to a short circuit or the like, and energy saving of the chiller is possible.

Furthermore, it becomes possible to predict chiller deterioration (aging) by monitoring the coefficient of performance and its variation during chiller operation. It constantly monitors whether the coefficient of performance is smaller than the set COP (indicating a slight deterioration state), and issues an alarm if it is smaller. As a result, slight deterioration can be automatically predicted, and maintenance can be performed every time an alarm is issued.
Regular maintenance cost can be reduced and life cycle cost can be reduced.

Further, since a temperature sensor is provided for each chiller, it is possible to check for short circuit and disconnection of the thermo wiring. In addition, when multiple chillers are operating, even if there is a variation in the setting of the chiller capacity control thermostat, this is a method that can be adjusted. It is possible to prevent side-by-side operation, in which a part of the ON-OFF operation occurs.

In the above embodiment, the case where the number of chillers is three has been described, but the present invention is not limited to this.

〔The invention's effect〕

As described above, according to the present invention, each of the plurality of air-cooled refrigerators is separately provided with means for detecting the inlet / outlet temperature, the flow rate, and the power consumption of the air-cooled refrigerator, and based on these detection signals. Calculate the load (heat quantity) of the operating air-cooling type refrigerator, the electric energy of each operating air-cooling type refrigerator, the coefficient of performance of each operating air-cooling type refrigerator, and determine the appropriate number of operating air-cooling type refrigerators from this calculation result. Since it is configured, it is energy-saving and life-saving.
Appropriate control of the number of units with consideration of cycle cost reduction is possible, and it is also possible to prevent low performance coefficient operation due to the short circuit of the air-cooled refrigerator, and also to prevent the air-cooled refrigerator from shifting to one side during multiple operations. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an example in which the operating number control device for an air-cooled refrigerator according to the present invention is applied to an operating number control device for an air-cooling heat pump chiller. FIG. 2 is a flow chart for explaining the operation in this embodiment. FIGS. 3A to 3C are graphs for explanation in this embodiment. FIG. 4 is a configuration diagram of a conventional air-cooling type heat pump chiller operating unit number control system. FIG. 5 is a conventional graph for explanation. [Explanation of symbols for main parts] 1,3,5 …… Chiller 2,4,6 …… Cold / hot water pump 10 …… Outgoing water header 14 …… Returning water header 16 …… Load 24,25,28,29 , 32,33 …… Temperature sensor 26,30,34 …… Flowmeter 27,31,35 …… Power meter 36 …… Control section.

Claims (1)

[Claims] 1. A plurality of air-cooled refrigerators connected in parallel to a load via forward and return water headers, a temperature sensor for detecting inlet / outlet cold water temperature of each of the air-cooled refrigerators, and each of the air-coolers. Flowmeter for detecting the flow rate of cold water flowing through the refrigerator, a power meter for detecting the electric energy of each air-cooled refrigerator, based on the detection signal detected by each of the temperature sensor, each flowmeter and each power meter A control unit that calculates the load of each operating air-cooled refrigerator, the coefficient of performance of each operating air-cooled refrigerator, and the power consumption of each operating air-cooled refrigerator, and determines the appropriate number of operating air-cooled refrigerators from the calculation result. In the control unit, the number of operating refrigerators is provisionally determined by the aggregate value of the loads of the refrigerators obtained by multiplying the flow rate of the refrigerators by the inlet / outlet temperature difference of the refrigerators, and at the same time, 1 when the power consumption of the machine is above the rating
An operation number control device for an air-cooled refrigerator, which decides to increase the number of units and decides to decrease one unit when there are multiple refrigerators with power consumption of 50% or less.