JPH0336843Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a device for controlling the number of operating water chillers/heaters having capacity control valves.

[Conventional technology]

In air conditioning systems, etc., multiple water coolers and hot water machines are installed, and the amount of heat consumed by the load equipment is taken as the load amount, and the number of water coolers and hot water machines in operation is controlled according to the increase or decrease in this amount. If you want to simplify the instrumentation without using a water heater, detect the opening of the capacity control valve of the water chiller/heater, determine the operating capacity of each chiller/heater, and use this as the load amount to control the number of machines in operation. It has become something to do.

[Problem that the invention attempts to solve]

However, when using a centrifugal chiller as a cold/hot water machine, a current limiter is inserted to prevent the drive motor from overloading, and this also limits the vane opening as a capacity control valve. When using a gas absorption type water chiller/heater or chiller, the maximum opening of the gas valve or steam valve for capacity control is mechanically fixed for adjustment, so there is a difference between the capacity control valve opening and the actual opening. The relationship with driving ability has become extremely complex,
It is not possible to accurately determine the load amount from the opening degree of the capacity control valve, resulting in a problem in which the number of operating vehicles is inaccurately controlled.

[Means for solving problems]

In order to solve the above-mentioned problem, the present invention is constructed by the following means.

That is, a multiplication means for multiplying the capacity control valve opening command value for the water chiller and hot water machine by the corresponding rated capacity value for each chiller and hot water machine, an adding means for summing the results of each multiplication by the multiplication means, and A control means is provided for controlling the number of operating chiller/hot water machines by using the addition result by the addition means as the current amount of heat consumption.

[Effect]

Therefore, the opening degree of the capacity control valve becomes directly irrelevant to the control, and each opening command value is determined according to the temperature of cold and hot water corresponding to the actual opening degree of the capacity control valve, so it naturally differs from the actual opening degree. When the operating capacity and the opening command value match, and the opening command value is multiplied by the rated capacity, the actual operating capacity can be determined.If these are added together, the total capacity of each water chiller/heater in operation can be calculated. is obtained, which approximately indicates the current load amount, and the control status of the number of operating vehicles based on this becomes accurate.

〔Example〕

Hereinafter, details of the present invention will be explained with reference to figures showing embodiments.

Figure 2 is an instrumentation diagram, in which a plurality of pumps 1 ₁ to 1 _o and a plurality of cold/hot water machines (hereinafter referred to as CHW) 2 ₁ to 2 _o such as gas absorption type chilled/heated water machines, refrigerators, and boilers are installed. The incoming water is sent under pressure by the pumps 1 ₁ to 1 _o to the pipe 4 via the header 3 via the CHWs _{2 1} to 2 _o .
The water is supplied by the fan coil unit and other load equipment (hereinafter referred to as LE) 5, and then reaches the header 7 as return water through a pipe line 6, and is again pressure-fed by the pumps ₁₁ to _1o , and circulates through the above route. It has become something to do.

Furthermore, a bypass pipe line 8 and a bypass valve 9 are provided between the headers 3 and 7, and the differential pressure between the headers 3 and 7 is measured by a differential pressure gauge 11, and control is performed according to this measured value. A device (hereinafter referred to as CNT) 12 gives an opening command to the bypass valve 9, controls the sending pressure of the incoming water, and also controls the temperature gauge 14 provided in the header 7.
While monitoring the return water temperature _T2 by
Thermometers 15 1 to ₂ on the delivery side pipes of CHW2 ₁ to 2 _o
15 _o are provided, and each _{CHW2 1 to}
2. While controlling the opening degree of the capacity control valve of each _o ,
The load amount is determined based on this capacity control valve opening command value, and the number of operating CHWs _{2 1} to 2 _o is controlled accordingly.

The CNT 12 sends and receives data signals to and from the central control unit (not shown in the diagram) via the transmission path 19, and receives basic control data, etc., while also transmitting control status monitoring data, etc. It has become something to do.

Figure 3 is a block diagram of the CNT12, which includes a processor such as a microprocessor (hereinafter referred to as CPU).
21, fixed memory (hereinafter referred to as ROM) 2
2. A variable memory (hereinafter referred to as RAM) 23 and interfaces (hereinafter referred to as I/F) 24 to 28 are arranged around the periphery, and these are connected by a bus bar.
Based on the input data Di such as each measurement output given via the I/F 24 and the data received via the communication I/F 26, the CPU 21 reads the ROM 22.
It executes the commands inside to perform control calculations and control decisions, and sends output data Do as a command to each control target part via the I/F 25.

Note that the CPU 21 executes instructions while accessing necessary data from the RAM 23 during control calculations and control decisions.
Display data is sent to the display unit (hereinafter referred to as DP) 29 via I/F 27 to display the control status, and the keyboard (hereinafter referred to as DP) via I/F 28 is sent to the display unit (hereinafter referred to as DP) 29.
KB) Depending on the operating ability of 30, set or update data to RAM 23, and
These DPs 29 are used for display.

FIG. 4 is a front view showing the operation panel of the CNT 12, in which a multi-digit character display 31 and a plurality of indicator lights 32 are provided, which constitute a DP 29, and a KB 30 is provided. The display 31 displays data or numerical values using alphanumeric characters or symbols and numbers, while an indicator light 32 provided corresponding to the name plate 33 displays alarms and the like.

FIG. 5 is a flowchart of the control status of the number of operating units by the CPU 21. First, today's first "At startup?" 101 is determined, and if this is Y (YES), the "Load amount calculation" 102 and the calculation result are performed. “Determine the number of operating units N _F ”103 at the time of startup based on
Maximum number of operable CHW2 ₁ to 2 _o “Nmax<
_NF ? ”111, and if it is N (NO), “send start command” 112 to the CHW that should be operated immediately, but if “ _N After replacing it with Nmax, the process moves to step 1112, and by comparing it with the return water temperature set value Tsp, in the case of cooling, “T ₂ < Tsp? ``This starting state is maintained while 114 is N.

In addition, in step 102, the load amount L _F at the time of starting is determined by calculating the following equation, for example.

L _F = 0.5・L _FY +0.5・L _MY ...(1) However, L _FY : Calculated load amount at the start of the previous day L _MY : Actual load amount at the start of the previous day For example, N _F is determined according to the predetermined cyclically operating order of the CHWs _{2 1} to 2 _o and the rated capacities of the CHWs _{2 1} to 2 _o .

Next, if step 114 is Y, "load amount calculation" 121 described later and "determination of number of operating vehicles N" 122 similar to step 103 based on the calculation results are performed,
As in step 111, check "Nmax<N?" 123, and if it is N, check immediately; if it is Y, check "N←Nmax" 124 as in step 113, and then check in step 112. In the same manner as above, "send start command" 131 is performed, and steps 101 and subsequent steps are repeated.

FIG. 6 is a flowchart showing the details of step 121, in which a counter configured in the CPU 21 to count the rank i of CHWs _{2 1} to 2 _o is set to "1" by "i=1" 201, and "Toi import" 202 is performed according to the contents of the thermometer 15 1 to 15 o, thereby storing the measured values from the corresponding one of the thermometers 15 ₁ to 15 _o into the RAM 23 and setting the settings stored in the RAM 23 in advance. Read out the corresponding value from the value Tsp using "Tspi readout" 203, perform "control calculation" 211 such as PID using Toi and Tspi, and thereby obtain the capacity control valve opening command value Di as a % value. , read out the corresponding Ri from the constant rated capacity value R of CHW2 ₁ to 2 _o stored in the RAM 23, calculate the individual load amount Li by the calculation of "Ri・Di=Li" 212, and then calculate "i=n". ?”221
is checked, and while this is N, “i=i+1”
A counter is registered in step 222, and steps 202 and subsequent steps are repeated.

However, Li obtained in step 212 is
It is stored in the RAM 23.

Next, if step 221 is Y, RAM2
Perform addition using Li in 3 and get “ΣLi=L”231
The current load amount L is determined by the calculation.

In addition, L _MY used in equation (1) was also measured, and
It may be stored in the RAM 23.

Further, Di determined in step 211 is separately sent to each CHW _{2 1} to 2 _o as a capacity control valve opening command signal.

Figure 1 is a functional block diagram that performs the above control, and the measured values from each thermometer ₁₅₁ to _15o .
T ₀₁ to _{T 0o} and set values T _sp1 to T _spo are respectively given to control calculators 61 ₁ to 61 _o that perform PID calculations, etc., and corresponding to each of these % value outputs D ₁ to D _o , respectively. The rated capacity values R ₁ to _{R o} of CHW _{2 1} to 2 _o are multiplied by multipliers 62 ₁ to 62 _o , respectively, to produce signals L ₁ to L _o indicating the capacity, and these are summed by an adder 63, and the load In addition to serving as a signal indicating the amount L,
The signal is supplied to a logic circuit 64 as a control means for controlling the number of operating vehicles.

Therefore, the circuit 64 changes the load amount L to the current value.
The number of units in operation is determined as the amount of heat consumed by LE5, and the start command signals S ₁ to _{S o} are set accordingly.
Send to CHW2 ₁ to 2 _o .

On the other hand, each output D ₁ to D _o is sent to the capacity control valve of each CHW 2 ₁ to 2 _o as a signal indicating the opening command value, thereby controlling the operating capacity of each CHW _{2 1} to 2 _o . be done.

In addition, depending on the opening command value D ₁ to D _o, the outgoing water temperature T ₀₁
~T _0o is determined, and this is the control calculator 61 ₁ ~
61 _o to the opening command values D ₁ to _{D o} , and each temperature T ₀₁ to _{T 0o} and the opening command value D ₁ to D _o
Since a feedback loop via the capacity control valve opening of each CHW2 ₁ to 2 _o is formed between them, the capacity control valve opening and the opening command value D ₁ to _Do are in agreement In equilibrium, even if there is a restriction on the capacity control valve opening, the opening command values D ₁ to _{D o} indicate the actual capacity control valve opening.

In addition, the rated capacity R ₁ to _{R o} is determined by the capacity control valve opening degree.
This is the value at 100%, and the opening command value D ₁
The actual operating capacity can be found by multiplying ~D _o , and the sum of these approximates the amount of heat consumed by LE5, so by determining the number of operating units using this as the load amount, accurate control of the number of operating units can be performed. It can be done.

Therefore, with simple instrumentation that does not use flowmeters, etc., accurate control of the number of operating CHW2 ₁ to 2 _o can be achieved, and the maximum opening degree of the capacity control valve on the CHW2 ₁ to 2 _o side can be adjusted, etc. Even if modified, CNT
12 does not require any changes in settings and is easy to maintain and handle.

However, the configurations in Figures 1 to 4 can be selected arbitrarily depending on the situation, and the configurations in Figures 5 and 6
In the figures, various modifications can be made, such as replacing the steps or replacing them with equivalent ones, or omitting unnecessary steps, depending on the conditions.

[Effect of idea]

As is clear from the above explanation, according to the present invention, accurate control of the number of operating CHWs is performed using simple instrumentation, and therefore a great effect can be obtained in controlling the number of operating heat source devices that have various capacity control valves. .

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Fig. 1 is a functional block diagram, Fig. 2 is an instrumentation diagram, Fig. 3 is a block diagram of CNT, and Fig. 4 is a front view showing the operation panel of CNT. FIG. 5 is a flowchart of the control situation, and FIG. 6 is a flowchart of calorific value calculation. 2 ₁ ~ 2 _o ... CHW (water cooler/heater), 4, 6... Pipe line, 5... LE (load equipment), 12... CNT (control device), 14, 15 ₁ - 15 _o ... Temperature Total, 21...
...CPU (processor), 22...ROM (fixed memory), 23...RAM (variable memory), 24-28
...I/F (interface), 61 ₁ ~ 61 _o ...
...Control computing unit, 62 ₁ to 62 _o ... Multiplier, 63...
...Adder, 64...Logic circuit.

Claims (1)

[Scope of utility model registration request] Equipped with multiple hot and cold water machines with capacity control valves,
In a device that supplies incoming water to a load device and controls the number of operating chiller/hot water machines according to the amount of heat consumed by the load device, the capacity control valve opening command value for the chiller/heater and the command value thereof are provided. a multiplier for multiplying each water chiller/hot water machine by a corresponding rated capacity value; an adding means for summing up the results of each multiplication by the multiplication means; 1. A control device for controlling the number of operating cold/hot water machines, characterized by comprising: a control means for controlling the number of operating cold/hot water machines.