JPH03148550A - Operation controller for refrigerating plant - Google Patents

Abstract

PURPOSE:To improve a controlling characteristic by a method wherein a capacity of a compressor is increased or decreased step by step every specified time in response to a temperature difference and at the same time when the temperature difference is widely displaced, the setting time for controlling the capacity is changed to show a short time. CONSTITUTION:A signal outputting means 8 may compare a temperature of a controlled item to be detected by a temperature sensing means Th in every predetermined set time, output an increasing or decreasing signal in response to a temperature difference and control a capacity of a compressor 1 by an operation controlling means 51 in such a way as it is increased or decreased step by step or kept at that value. In this case, when the temperature difference is more than a predetermined value at a request side, an up-side varying means 52 may change a set time for an instruction signal output of a signal outputting means 8 to show a short period and in turn when it returns to a predetermined value of temperature difference value, a down-side varying means 53 changes the set time to have an elongated time. When the temperature difference is low, a stability in control is maintained and when the temperature difference is widely displaced, a follow-up characteristic against a rapid increasing of load is improved and then a converging time for the set temperature can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an operation control device for a refrigeration system that controls the capacity of a compressor in a plurality of steps according to the refrigeration load. Concerning measures to improve followability.

(Prior Art) Conventionally, as disclosed in JP-A-59-185931, for example, in an air conditioner equipped with a compressor that can be adjusted in multiple steps, the difference between the indoor air temperature and the set temperature has been known. It compares the temperatures at predetermined set time intervals and outputs a capacity command signal that increases, decreases or maintains the capacity of the compressor one step at a time according to the temperature difference value, and also outputs a capacity command signal that increases or decreases the capacity of the compressor by one step or maintains the capacity of the compressor according to the value of the capacity command signal. By controlling the capacity to increase/decrease or maintain it, and by shortening the setting time for outputting a capacity command signal only when the device is started, it is possible to prevent overruns caused by excessive capacity while maintaining indoor There is a known technique that attempts to quickly converge the temperature to a set temperature.

(Problems to be Solved by the Invention) For example, in a refrigeration system in which the coolant in a chiller circuit is cooled by heat exchange with a refrigerant in an evaporator,
When controlling the operating capacity of the compressor to increase or decrease one step at a predetermined period according to the temperature difference between the coolant temperature and the set temperature, as in the conventional system described above, the period is determined by the control stability and followability. determined by striking a balance with That is, if the period is too long, the followability deteriorates, and if the period is too short, the stability deteriorates, so the value is set to satisfy both.

However, even if the capacity of the compressor is controlled at such predetermined intervals, the following problems occur not only when the device is started up but also during subsequent operation. That is, when the load on the chiller circuit suddenly changes and the coolant temperature deviates significantly from the set temperature, for example, when the coolant temperature is too high, it takes a long time for the coolant to approach the set temperature, resulting in poor control performance. Additionally, when the coolant temperature is low, in addition to the above-mentioned conditions, there is a risk that the coolant may freeze, so the control function may be disabled due to special operating conditions, such as forced thermo-off. There is a risk that things will get worse.

The present invention has been made in view of the above, and its purpose is to provide a means for accelerating followability without impairing control stability when the temperature of a controlled object deviates significantly from the set temperature. The purpose is to quickly respond to sudden changes in load, etc., thereby solving the above-mentioned problems.

(Means for Solving the Problems) In order to achieve the above object, the means for solving the problems of the present invention is to shorten the period of controlling the increase/decrease in the capacity of the compressor.

Specifically, the first solution is as shown in FIG.
(excluding the dashed-dotted line part), a variable capacity compressor (1) adjustable in multiple steps, and a heat source side heat exchanger (2),
The refrigeration system is assumed to be equipped with a user-side heat exchanger (4).

As an operation control device for the refrigeration equipment, there is provided a temperature detection means (Th) for detecting the temperature of a controlled object, and a temperature of the controlled object detected by the temperature detection means (Th) and a set temperature at every predetermined set time. A signal output that outputs a load-up signal that instructs to increase the capacity of the compressor (1), a load-down signal that instructs to reduce the capacity of the compressor (1), and a keep signal that instructs to maintain the capacity of the compressor (1) by comparing the two and according to the temperature deviation value between the two. means (8); and operation control means (51) which receives the output of the signal output means (8) and controls the capacity of the compressor (1) to be increased, decreased, or maintained one step at a time.

Furthermore, upon receiving the outputs of the temperature detection means (Th) and the signal output means (8), when a load-up signal is output in a state where the temperature deviation value is equal to or higher than a predetermined value on the capacity requesting side, the signal output means (8) Up side changing means (52) for changing to shorten the setting time for outputting the command signal.
).

As shown in FIG. 1 (not including the broken line portion), the second solution is based on the same refrigeration system as the first solution, and uses the first solution as an operation control device for the refrigeration system. An operation control means (51) similar to the means is provided, and furthermore, it receives the outputs of the temperature detection means (Th) and the signal output means (8), and when the temperature deviation value exceeds a predetermined value on the non-capacity request side, A down side changing means (53) is provided for changing the setting time for the signal outputting means (8) to output a command signal when a load down signal is outputted.

The third solution, as shown in FIG. 1A (including the broken line portion and the dashed-dotted line portion), is based on a refrigeration system similar to the first solution, and as an operation control device for the refrigeration system,
The configuration includes an operation control means (51) and an up side changing means (52) similar to the first solving means, and further includes a down side changing means (53) similar to the second solving means. .

The fourth solution is the above-mentioned first solution. The set time in the second or third solving means is set to different values on the side where the capacity of the compressor (1) increases and the side where it decreases.

A fifth solution means, as shown in FIG. In the third or fourth solution, the compressor (1) has an extremely low load step whose capacity is lower than the lowest step in the normal operating region, and in addition, when operating at the lowest step in the normal operating region, the compressor (1) When receiving a load down signal from the signal output means (8), the control of the operation control means (51) is forcibly stopped to maintain the capacity of the compressor (1) at an extremely low step for a set time. The forced capacity holding means (54) stops the compressor (1) when it receives a load-down signal from the signal output means (8) after the set time has elapsed, while receiving a load-up signal or a keep signal. When the operation control means (5)
The configuration includes an operation control means (55) that controls the operation to return to the normal operation according to 1).

The sixth solution is the first solution mentioned above. Second. Third. In the fourth and fifth solution means, the v4 control target is a cooling liquid such as a chiller circuit, the user-side heat exchanger (4) is a cooler that cools the cooling liquid by heat exchange with a refrigerant, and the temperature detection means ( Th
) is used to detect the temperature of the coolant at the outlet side of the cooler (4) of the chiller circuit.

(Function) With the above configuration, in the invention of claim [1], the signal output means (8) detects the temperature to be controlled and the set temperature detected by the temperature detecting means (Th) every predetermined set time. The load-up signal is compared according to the temperature deviation between the two,
A load down signal or a keep signal is output, and the operation control means (51) controls the capacity of the compressor (1) to increase/decrease or maintain it one step at a time.

Here, when the temperature deviation value exceeds a predetermined value on the capacity requesting side, the up side changing means (52) changes the signal outputting means (8) to shorten the set time for outputting the command signal. Therefore, when the temperature of the controlled object is around the set temperature, control stability is maintained, and when the temperature of the controlled object greatly deviates from the set temperature, the ability to follow sudden increases in load is improved. , the time for convergence to the set temperature will be shortened.

In the invention of claim (2), similarly to the invention of claim (1), the ability to follow a sudden decrease in load is improved, the time for convergence to the set temperature is shortened, and as a result,
Stopping of the compressor (1) due to thermo-off is avoided, and control becomes stable.

In the invention of claim (3), the effect of the invention of claim (1) or (2) can be obtained simultaneously by the up side changing means (52) and the down side changing means (53), and the effects of each invention are combined. The effect will be obtained.

In the invention as claimed in claim 4, since the set times are determined to be different on the load-up side and the load-down side, in response to the different sensitivity of the controlled object temperature during load-up and load-down, The balance between followability and stability of control can be maintained at an appropriate value.

Claim (In the invention of claim 9, the above claims (1), (2),
In addition to the invention C3) or 4), the operation control means (51
), if a load down signal is output from the signal output means (8), the forced capacity holding means (54) will maintain the capacity of compression tl & (1) for a set time. It is maintained at an extremely low step that is lower than the lowest step in the normal operation area, and the forced control means (5
5), the compressor (1) is controlled to be stopped only when the load down signal is still being output after the set time has elapsed, so stopping the compressor (1) due to thermo-off is avoided as much as possible. This will further stabilize control.

In the invention of claim [6], the above claims (1) and (2)
, C3).

In the invention of (4) or (9), the capacity of the compressor (1) is controlled by the signal output means (8) according to the temperature deviation between the coolant temperature at the outlet of the cooler (4) of the chiller circuit and the set temperature. Since the functions of the above-mentioned inventions are performed to control the increase and decrease, the compression s
A balance between control stability and followability can also be achieved with respect to the chiller circuit cooler (4) outlet temperature, which sensitively follows the capacity control in (1).

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

Figure 2 shows a piping system for a refrigeration system and a chiller circuit according to an embodiment of the present invention. A refrigeration device (31) for cooling is arranged.

The refrigeration system (31) includes a compressor (1) whose capacity is adjusted in multiple steps by an inverter (6), and a condenser (
2), a pressure reducing valve (3), and a cooler (4) that functions as an evaporator and is a user-side heat exchanger that cools the coolant of the chiller circuit (30) as a controlled object, A refrigerant circuit (5) is configured by connecting each of the above-mentioned devices (1) to (4) through refrigerant piping.

That is, during operation of the refrigeration system, the refrigerant discharged from the compressor (1) is condensed in the condenser (2), reduced in pressure by the pressure reducing valve (3), and evaporated in the cooler (4). By circulating back to (1), the coolant in the chiller circuit (30) is cooled by heat exchange with the refrigerant in the cooler (4).

Here, the operating capacity Q of the compressor (1) is adjustable in 5 steps of 0.25, 50, 75° 100% of the rated capacity during normal operation, while Capacity 12 with lower capacity than the step in the operating area
% is made adjustable to an extremely low load step.

The outlet water pipe of the cooler (4) has a thermistor (temperature detection means) for detecting the outlet temperature of the cooling liquid.
Th) (detection section of the water temperature control thermostat) is arranged, and the output of the thermistor (Th) is connected to a temperature regulator (8) which is the adjustment section of the water temperature control thermostat.

That is, based on the magnitude of the outlet temperature of the cooling water cooler (4) detected by the thermistor (Th) and its set temperature, the total capacity of the compressor (1) is increased or decreased from the temperature controller (8). The temperature controller (8) is configured to output a command signal for instructing the temperature controller to do so, and the temperature controller (8) has a function as a signal output means. And the temperature regulator (
The signal 8) can be input to a controller (9) that controls the operation of the entire device.

Here, although not shown, three output terminals (Yl) to (Yl) are arranged in the temperature regulator (8). The above output terminals (Y+) and (Yz) are shown in Figure 3 (a) and (
As shown in b), two first and second set temperatures Tsl and Ts2 have a predetermined differential ΔT (for example, a temperature difference of about 2°C) relative to changes in water temperature (however, if Tsl<Ts2, each For example, the set temperatures Tsl and Ts2 are based on a predetermined individual differential (for example, a value of about 0.4°C) dT1. It outputs two outputs 1°2 which are switched on and off with dT2. In other words, when the water temperature rises, output 1 switches from on to off when the set temperature Tsl is reached, while when the water temperature falls, the output 1 switches from on to off when the water temperature
Output 2 switches from off to on when it reaches the set temperature Ts2 when the water temperature is decreasing, and switches from off to on when it reaches the set temperature Ts2 when the water temperature is rising.
sl+dT2), the switch is switched from off to on.

Then, depending on the combination of the output 1.2 of each terminal (Ys) and (Yz), the temperature controller (8) controls the controller (9) to control the compressor (la) as shown in Table 1 below. ), (lb) command signals for capacity control are output. In other words, if output 1 is on and output 2 is off, the water temperature is low, so the compressors (la) and (l
If outputs 1 and 2 are both on, output a load down signal that commands to reduce the total capacity in b), and output a keep signal that commands to maintain the current total capacity because the water temperature is within the set range. If 1 is off and output 2 is on, then
Since the water temperature is high, a load-up signal is output that instructs the total capacity to increase.

Table 1 l Output 11 Output 21 Command signal 1 ON OFF 10-Door down signal 11 ON ON I Keep signal 11 OFF ON 10-Door knob signal I
1 Off Off 1 Anti-freeze signal However, in Table 1 above, when both outputs 1 and 2 are off, it means that the water pipes are frozen, and in that case, so-called anti-freeze operation to prevent freezing is activated. It has been like that.
- On the other hand, as shown in FIG. 3(c), the output terminal (Y3) is connected to a temperature on the performance requesting side that is higher than the first set temperature Tsl by a predetermined temperature range B (for example, a value of about 2.3°C). An output 3 is output which switches the output value between the upper limit value Tu and the lower limit value TI on the non-capacity demanding side, which is lower than the second set value Ts2 by a predetermined width B. That is, it is off near the set temperature, and when the water temperature rises and enters the high temperature range and reaches the upper limit value Tu, it turns on and issues an upper limit signal, while the water temperature drops from that state to a predetermined value below the upper limit value Tu. When the differential dT3 (for example, a value of about 0.degree. 3.degree. C.) reaches a lower value (Tu - dT3), it is switched off and the upper limit signal is released.

In addition, in the low temperature range of water temperature, when the water temperature decreases and reaches the above lower limit value Tl, it turns on and issues a lower limit signal.
When the water temperature rises from that state and reaches a value (T, l? + dTa) higher than the lower limit value TI by a predetermined differential dT4 (for example, a value of about 063 degrees Celsius), it switches off and releases the lower limit signal. is being done.

The operating capacity of the compressor (1) is controlled by the controller (9) in accordance with the command signal from the temperature regulator (8). The details of the control will be explained below based on the flowcharts of FIGS. 4A and 48. 4th A
The figure shows the main flow. After initialization is performed in step S1, it is determined in step S2 whether or not a load down signal is output. If it is not output, the process proceeds to step S3, and the following control is performed. I do.

That is, in step S3, the capacity of the compressor (1) is 12
After maintaining the compressor (1) at an extremely low funnel step for a certain period of time, a startup operation is performed to maintain the capacity of the compressor (1) at the lowest step of normal operation, and the total capacity is stored as Q-1 in step S4. Then, it is determined in step SS whether or not there is an upper limit signal, and if the upper limit signal is not output, the process proceeds to step S6 to set the first set time, which is the set time of the first timer (not shown). 1 is the standard value on the up side A+
(for example, about 180 seconds), and if the upper limit signal is output, the first
Set the timer setting time to 1 as the standard value A above, half the value A,
/2 (for example, a time of about 90 seconds), and proceed to step S8-.

Then, in step S8, the first timer (not shown) starts the count T1, and in step S9, waits until the count T1 becomes 1 or more for the first set time, and during that time, the load is loaded by the determination in step Sm. If the down signal is input, the process moves to step S24, which will be described later. If the load down signal is not input manually, the timer count is cleared in step Sll, and then it is determined in step S12 whether or not the load up signal is output. .

Here, in the determination at step 512, if the load-up signal is not output, that is, if it is a keep signal, the control in steps S5 to sn is repeated to maintain the capacity of the compressor (1), while the load-up signal is output. is output, proceed to step 3.3 and determine that the total volume ffiQ is 100.
% is 4 (step). If it is 4 (step), the capacity cannot be increased, so the process returns to step S5. If the total capacity jiQ is not 4 (step), step S>s Then, the total capacity Q is increased by one step as Q-Q+1. And step SI5
Then, each compressor (
1) Capacity increase control is performed to increase the capacity by one step.

On the other hand, if it is determined in step S2 that the load down signal is output, the process proceeds to step 516, where it is determined whether or not the lower limit signal is output, and if there is no lower limit signal, the second load down signal is output in step sy. The second set time 2, which is the set time of the timer, is set to a predetermined standard value A2 (for example, about 45 seconds), and if there is a lower limit signal, the second set time Z is set to the above standard value A2 in step StS. Half Az /
2 (for example, a time of about 22 seconds), and the process proceeds to step S19°.

Thereafter, in step 519, a second timer (not shown) starts counting T2, and the step S unit waits until the count Tz reaches the second set time of 2, during which time the load-up signal is detected as determined in step S21. If the load-up signal is inputted, the process moves to step S5, and if the load-up signal is not input manually, the count T2 is reset to "0" in step S22, and then the process moves to step Sn, where it is determined whether the total volume ffiQ is 0 steps or not. do. - Then, if the total capacity Q is 0 (step) in the determination in step S23, the capacity cannot be reduced, so the process returns to step S19 and repeats the control in steps S19 to S22, while the total capacity Q is 0 (step). If not, in step S24, Q-Q-l and the total volume ffiQ are reduced by one step, and in step Sδ, it is determined which of 1 to 4 (steps) this changed total volume jlQ is. , if it is not 0 (step), that is, the compressor (
If the stop command of 1) has not been issued, in step S2B, the frequency of the inverter (6) is adjusted according to the command to control the capacity of the compressor (1), while the capacity of the compressor (1) after the change is adjusted. If the capacity is 0 (step), forced operation shown in the flowchart of FIG. 48 is performed in step S17.

That is, in step R1, the compressor (1) is operated at a capacity of 12%, which is an extremely low load step, and at the same time, a count T3 of a third timer having a set time z (for example, a time of about 45 seconds) is started. Then, in step R2, wait until the count T3 of the first timer reaches the set time of 3 or more, and when the set time of 3 has elapsed, proceed to step R3, clear the count T3 of the third timer, and in step R4,
It is determined whether there is still a load down command.

Here, if there is still a load down command, step RS
On the other hand, if there is no load down command, that is, if a load up signal or a keep signal is output, the process advances to step R6, and the compressor (1) is stopped.
At the same time as performing 25% capacity operation, the set time is set to 4.
(for example, a count of a fourth timer (not shown) having a time of about 45 seconds) T4, and in step R7, a second timer
Wait until the timer count T4 reaches the set time of 4 or more, and when the set time of 4 elapses, the fourth time is counted in step R8.
After clearing the timer count T4, it is determined in step R9 whether a load down signal is further output.

If the load down signal is output, the process moves to step R5 and the compressor (1) is stopped, while
If the load down signal is not output, normal operation is resumed.

In the above flow, steps 88 to 515 and 513
53 constitutes an operation control means (51) which receives the output of the signal output means (8) and controls the capacity of the compressor (1) to be increased, decreased or maintained one step at a time. Then, when the load-up signal is output in a state where the temperature deviation value is equal to or higher than the predetermined value on the capacity request side by the control in steps 85 to S7, the signal output means (8)
Up-side changing means (52) is configured to change the first set time for outputting the load-up signal so as to shorten 1, and in steps SI6 to SI8, the temperature deviation value becomes equal to or higher than a predetermined value on the non-capacity request side. Down side changing means (53) is configured to change the second set time during which the signal output means (8) outputs the load down signal so as to shorten the second set time by 2 when the load down signal is output in a state where the load down signal is output.

Furthermore, in the invention of claim [4], steps R1 and R
According to the control in step 2, when a load down signal is received from the signal output means (8) during operation at the lowest step in the normal operation region, the control of the operation control means (51) is forcibly stopped and the compressor ( A forced capacity holding means (54) is configured to maintain the capacity of step 1) at an extremely low step for a set time, and by controlling from step R4 to RS or R7, the signal output means (8) is activated after the set time has elapsed. Forcible control means (55) for controlling the compressor (1) to stop when it receives a load-down signal, and to return to normal operation control by the operation control means (51) when it receives a load-up signal or a keep signal. ) is configured.

Therefore, in the invention of claim (1), the temperature controller (signal output means) (8) compares the temperature to be controlled detected by the temperature detection means (Th) and the set temperature at each predetermined set time. , a load-up signal, a load-down signal, or a keep signal is output according to the temperature difference between the two, and the capacity of the compressor 1 (1) is controlled to increase/decrease or maintain it step by step by the operation $1m means (51). Ru.

Here, when the temperature deviation value exceeds the predetermined value on the capacity requesting side, that is, when it exceeds the upper limit Tu of the above embodiment, the up side changing means (52) causes the signal outputting means (8) to is changed to shorten the set time (the first set time in the above embodiment is 1) for outputting the command signal. In other words, in the case of the above-mentioned conventional system in which the capacity is controlled at fixed set time intervals regardless of the value of the temperature deviation value, the control target is, for example, the outlet of the chiller circuit (30) as in the above-mentioned embodiment. In the case of water temperature, even if the outlet water temperature changes sensitively to the result of controlling the capacity or capacity of the compressor (1), there may be concerns about control where the outlet water temperature exceeds the set temperature and changes significantly above or below the set temperature. Qualitativeness can be avoided. However, on the other hand, when the water temperature rises higher than the set temperature, it takes time to pull down from that value to the set temperature, and there is a possibility that good water temperature control cannot be performed.

In contrast, in the present invention, when the load suddenly increases and the outlet water temperature exceeds the upper limit value Tu, the up side changing means (52) uses the set time for outputting the command signal of the signal output means (8). (first set time 1) is changed to be shorter, and the interval between capacity adjustments of the compressor (1) by the operation control means (51) is shortened, so when the water temperature is around the set temperature, the stability of the control is improved. While maintaining the water temperature, it is possible to improve the ability to follow sudden changes in load when the water temperature significantly deviates from the set temperature, and in particular, it is possible to shorten the pull-down time to the set temperature. be.

In the invention of claim (2), similarly to the invention of claim (1), when the outlet water temperature decreases beyond the lower limit due to a decrease in load, the down side changing means (53)
Since the set time (second set time 2) for the signal output means (8) to output the command signal is changed to be shorter, the ability to follow sudden changes in load is improved, and the outlet water temperature can be recovered quickly. can be achieved. Moreover, thereby, the start of frost protection operation, that is, the stoppage due to thermo-off of the compressor (1) can be avoided as much as possible. In particular, in the case of controlling the outlet water temperature as in the above embodiment, the compressor (
The result of capacity control in 1) is sensitively manifested as a change in water temperature, so if the compressor (1) thermo-off stops frequently, the water temperature will change significantly during that time, making water temperature control unstable. However, such a compressor (1
), the control can be stabilized by avoiding the thermo-off stop.

In the invention as claimed in various claims, the effects of the invention as claimed in claim (1) or (2) can be obtained simultaneously by the up side changing means (52) and the down side changing means (53), and the effects of each invention are combined. This will result in more effective results.

In the invention of claim 4, as in the above embodiment, the set time (first set time) l for outputting the command signal of the signal output means (8) on the load-up side is equal to the set time (first set time) l on the load-down side. 2 setting time) is set to a value larger than tz. In other words, the set times are set to be different between the load-up side and the load-down side. In other words, since the change in temperature to be controlled with respect to the result of capacity control of the compressor (1) generally differs between load-up and load-down, it is necessary to always maintain control followability and stability at good values. However, in the present invention, it is possible to maintain the balance between followability and stability of control at an appropriate value in response to such different sensitivities of controlled object temperatures.

Claim (in the invention of S, the above claim Cυ, (2),
In addition to the invention (3) or (4), the operation control means (51
), when a load down signal is output from the signal output means (8), the capacity of the compressor (1) is maintained for a set time by the forced capacity holding means (54). The compressor (1) is maintained at an extremely low step that is lower than the lowest step in the normal operation region, and the compressor (1) is controlled by the forced control means (55) only when the load down signal is still being output after the set time elapses. Since the compressor (1) is controlled to stop, the thermo-off stop of the compressor (1) is avoided as much as possible. Therefore, in each of the above inventions, control can be further stabilized.

In the invention of claim (6), the above claims (1) and (2)
, (3).

In the invention of (4) or (5), the signal output means (8)
According to the temperature deviation between the coolant temperature at the outlet of the cooler (4) of the chiller circuit (30) and the set temperature, the compressor (1)
A command signal is outputted to increase or decrease the capacity of the compressor (1), and the operation control means (51) controls the capacity of the compressor (1) to increase/decrease or maintain it one step at a time. Here, since the outlet temperature of the cooler (4) of the chiller circuit (30) sensitively follows the capacity control of the compressor (1), in order to ensure control stability, the sampling time for capacity control is In other words, in the above embodiment, the setting time is 1. , 1z must be set to a certain degree. Therefore, if the water temperature deviates significantly from the set temperature due to a sudden change in load, etc., it would be difficult to keep up with the control by sampling at standard set times and changing the capacity of the compressor (1) one step at a time. However, even in such a case, the above-mentioned inventions can ensure followability of control.

In the above embodiment, the compressor (1) is connected to the inverter (6).
), however, the present invention is not limited to such embodiments, and, for example, it may be possible to combine two compressors whose capacities are adjusted to full load and unload by an unloader mechanism. It may be something like that. However, the invention of claim 9 is limited to inverters, screw compressors, turbo compressors, etc., which have an extremely low load step in addition to the normal operation step.

(Effect of the invention) As explained above, according to the invention of claim 11, the capacity of the compressor is increased or decreased by one step at each predetermined set time depending on the temperature deviation between the temperature to be controlled and the set temperature. At the same time, when the temperature deviation greatly deviates from the required capacity side, the setting time for capacity control is shortened, so while ensuring stability of control around the set temperature, In some cases, it is possible to improve the ability to follow sudden changes in load, and it is possible to shorten the time for convergence to the set temperature.

According to the invention of claim (2), when the temperature deviation between the temperature to be controlled and the set temperature greatly deviates to the side where capacity is not required,
By changing the setting time for capacity control to a shorter time, it is possible to improve the ability to follow sudden changes in load, and to prevent the compressor from stopping due to thermo-off as much as possible. It is possible to expand the operable range of the machine.

According to the invention of claim (3), the capacity of the compressor is adjusted even if the temperature deviation between the temperature to be controlled and the set temperature deviates greatly to either the capacity-demanding side or the non-capacity-demanding side. Since the time is changed, the above claim (1)
The effects of the invention (2) and (2) can also be obtained.

According to the invention of claim (4), the above-mentioned claim (1), (
In the invention of 2) or (3), since the set time for adjusting the capacity of the compressor is made different between the load-up side and the load-down side, even if the sensitivity of the temperature to be controlled differs between the two, , it is possible to maintain a good balance between control stability and followability.

According to the invention of claim (5), the above-mentioned claim (1), (
2).

In addition to the invention of (3) or (4), when a load down signal is received during operation at the lowest step in the normal operating range, the compressor is not stopped immediately and the compressor is temporarily stopped at the lowest step in the normal operating range for a set time. Since the compressor is stopped only when there is still a load down signal after maintaining an extremely low load step lower than the load step, it is possible to avoid stopping due to the compressor's thermo-off as much as possible.
Control stability can be improved.

According to the invention of claim (6), the above-mentioned claim (1), (
2).

Since the inventions (3), (4), or (5) are applied to the control of the cooler outlet temperature of the chiller circuit, the cooler outlet temperature, which changes sensitively to changes in compressor capacity, can also be controlled. It is possible to exhibit the effects of improving control stability and followability according to each of the above-mentioned inventions.

[Brief explanation of the drawing]

FIG. 1A is a block diagram showing the structure of the invention of claims [1) to 4).
The lock diagram and the mlB diagram are block diagrams showing the configuration of the invention of claim 9. Figure 2 and the following diagrams show embodiments of the present invention, and Figure 2 is a piping system diagram showing the configuration of the refrigeration system and chiller circuit. , Figures 3(a) to (c) are explanatory diagrams showing the switching characteristics of the three outputs of the temperature controller in response to water temperature changes, Figures 4A and 4B show the control contents of the controller, and Figure 4A is the main FIG. 4B is a flowchart showing each subflow of forced control. 1 Compressor 2 Condenser (heat source side heat exchanger) 4 Cooler (user side heat exchanger) 8 Temperature regulator (signal output means) 51 Operation control means 52 Up side changing means 53 Down side changing means-54 Forced capacity holding means 55 Forced control means Th Thermistor (temperature detection means) TI Figure 18 A-1, /X C%11 Figure 1A 71 Ts, TsI Tu exit
N) II Compressor stop” 1 Fig. 48

Claims (6)

[Claims] (1) Variable capacity compressor that can be adjusted in multiple steps (
1), a heat source side heat exchanger (2), and a user side heat exchanger (4).
), a temperature detection means (Th) for detecting the temperature of a controlled object;
The temperature to be controlled and the set temperature detected by the compressor (
1) a load-up signal commanding to increase the capacity of;
A signal output means (8) for outputting a load down signal instructing to reduce the load and a keep signal instructing to maintain the load, and receiving the output of the signal output means (8), the compressor (1
) is provided with an operation control means (51) for controlling the capacity to be increased/decreased or maintained one step at a time, and receives the outputs of the temperature detection means (Th) and the signal output means (8) so that the temperature deviation value is determined as required by the capacity. The load-up side changing means (52) changes the setting time for the signal outputting means (8) to output the command signal when the load-up signal is outputted in a state where the load-up signal exceeds a predetermined value on the side. An operation control device for a refrigeration system characterized by the following. (2) Variable capacity compressor that can be adjusted in multiple steps (
1), a heat source side heat exchanger (2), and a user side heat exchanger (4).
), a temperature detection means (Th) for detecting the temperature of a controlled object;
The temperature to be controlled and the set temperature detected by the compressor (
1) a load-up signal commanding to increase the capacity of;
A signal output means (8) for outputting a load down signal instructing to reduce the load and a keep signal instructing to maintain the load, and receiving the output of the signal output means (8), the compressor (1
) is provided with an operation control means (51) for controlling the capacity to increase/decrease or maintain it one step at a time, and receives the output of the temperature detection means (Th) and the signal output means (8), and receives the output of the temperature detection means (Th) and the signal output means (8), A down side changing means (53) is provided for changing the setting time for the signal outputting means (8) to output the command signal when the load down signal is outputted in a state where the load down signal is equal to or higher than a predetermined value on the requesting side. An operation control device for a refrigeration system, characterized in that: (3) Variable capacity compressor that can be adjusted in multiple steps (
1), a heat source side heat exchanger (2), and a user side heat exchanger (4).
), a temperature detection means (Th) for detecting the temperature of a controlled object;
The temperature to be controlled and the set temperature detected by the compressor (
1) a load-up signal commanding to increase the capacity of;
A signal output means (8) for outputting a load down signal instructing to reduce the load and a keep signal instructing to maintain the load, and receiving the output of the signal output means (8), the compressor (1
) is provided with an operation control means (51) for controlling the capacity to be increased/decreased or maintained one step at a time, and receives the outputs of the temperature detection means (Th) and the signal output means (8) so that the temperature deviation value is determined as required by the capacity. up-side setting time changing means (52) for changing the setting time for the signal outputting means (8) to shorten the setting time for outputting the command signal when the load-up signal is output with the load-up signal being equal to or higher than a predetermined value on the side; , when the load down signal is output with the temperature deviation value being equal to or higher than a predetermined value on the non-capacity requesting side, the signal output means (8) changes to shorten the set time for outputting the command signal; An operation control device for a refrigeration system, comprising a changing means (53). (4) The set time is set to different values on the side where the capacity of the compressor (1) is increased and the side where the capacity is decreased. Operation control device for refrigeration equipment. (5) The compressor (1) has an extremely low load step that has a lower capacity than the lowest step in the normal operating range, and the load is lowered by the signal output means (8) during operation at the lowest step in the normal operating range. When receiving the signal, forcibly stop the control of the operation control means (51),
forced capacity holding means (54) for maintaining the capacity of the compressor (1) at an extremely low step for a set time; and after the set time has elapsed, when receiving a load down signal from the signal output means (8); The compressor (1) is provided with a forced control means (55) for controlling the compressor (1) to stop, while returning to normal operation control by the operation control means (51) when receiving a load-up signal or a keep signal. An operation control device for a refrigeration system according to claim (1), (2), (3), or (4). (6) The object to be controlled is the coolant in the chiller circuit, etc., the user-side heat exchanger (4) is a cooler that cools the coolant by heat exchange with the refrigerant, and the temperature detection means (Th) is in the chiller circuit. Claims (1), (2), characterized in that the temperature of the cooling liquid on the outlet side of the cooler (4) is detected.
(3), (4), or (5) the operation control device for a refrigeration system.