JPH02217755A - Turbo chiller operation control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an operation control device for a centrifugal chiller, and in particular,
The present invention relates to an operation control device for a centrifugal chiller that is suitable for stable operation even under operating conditions where the differential pressure between the condenser and the evaporator is small at startup.

[Prior Art] A conventional centrifugal chiller will be described with reference to FIG. 4.

FIG. 4 is a schematic configuration diagram of a conventional centrifugal refrigerator.

As shown in FIG. 4, a centrifugal refrigerator includes a compressor 1 that increases the pressure of refrigerant gas, a condenser 2 that cools and liquefies the increased pressure of the refrigerant gas with cooling water or air, and a depressurizer 3 that depressurizes and expands the refrigerant liquid. , an evaporator 4 which also evaporates the decompressed and expanded refrigerant liquid to generate cold water or cold air, and an evaporator 4 which is arranged on the suction side of the compressor 1, and which operates the opening degree of a plurality of vanes 5 by an actuator 6 to adjust the air volume. It is composed of a wind i adjustment mechanism 7, a temperature iA moderator 8 that detects the cold water outlet temperature of the evaporator 4, and controls the actuator 6 of the air volume adjustment mechanism 7 so that the detected temperature becomes a predetermined constant value. ing.

In applications where centrifugal chillers are operated throughout the year, there is a large difference in condensing pressure between summer and winter due to large differences in external conditions such as outside air temperature and cooling water temperature.
Therefore, in winter, the differential pressure between the condenser 2 and the evaporator 4 becomes small, and the flow of the refrigerant liquid is hindered.

On the other hand, at startup, the temperature of the cold water in the cold water pipe system 9 that flows through the evaporator 4 is high, so the temperature controller 8 instructs the vane opening degree to be 100% in order to keep the chilled water temperature at the planned constant value. Output. However, in reality, the vane opening is 100.
As a result of sending a much larger amount of refrigerant gas to the condenser 2 than the load equivalent to the load, a large amount of refrigerant liquid accumulates in the condenser 2, and an extremely small amount of refrigerant liquid remains in the evaporator 4. Become.

Furthermore, as prior art of this kind, 5, for example, Utility Model Publication No. 55-1
A technique described in Japanese Patent No. 5008 is known.

[Problems to be Solved by the Invention] As mentioned above, in the conventional operation control device for a centrifugal chiller, the pressure difference between the condenser and the evaporator decreases in winter;
At startup, a large amount of refrigerant liquid accumulates in the condenser, and there is an extremely small amount of refrigerant liquid on the evaporator side4.This reduces the performance of the evaporator and is likely to cause problems such as an abnormal drop in evaporation pressure. Ta.

The present invention was made in order to solve the above-mentioned problems in the conventional technology, and even if the outside air condition before startup is low, it prevents abnormal liquid accumulation in the condenser at startup, and provides stable operation throughout the year. It is an object of the present invention to provide an operation control device for a centrifugal chiller for maintaining the condition.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the operation control device for a turbo chiller according to the present invention includes a turbo compressor equipped with an air volume adjustment mechanism, a condenser, and an evaporator. , in an operation control device for a centrifugal chiller in which a wind iIR adjustment mechanism is controlled according to the temperature of a cold water system flowing through an evaporator, pressure detection means connected to the condenser and the evaporator;
The actuator part of the air volume adjustment mechanism is provided with a limit switch means that is turned on at the minimum throttle opening position of the refrigeration capacity, and after the throttle mechanism opens to the minimum throttle opening position at startup, the air volume UR is adjusted at that opening. The control circuit is configured to stop the adjustment mechanism and release the opening stop of the air volume adjustment mechanism when the detected value of the pressure detection means exceeds a specified value.

Additionally, the above object is achieved by the following means.

Install pressure detectors in the condenser and evaporator.

On the other hand, the air volume adjustment mechanism is usually provided with an interlock circuit to prevent the damper from closing at the minimum possible opening in order to prevent surging, but in the present invention, the surging prevention interlock of the air volume adjustment mechanism is used. However, the operation of the vane opening degree is controlled based on the output value of the pressure detector.

[Effect] The working of the above technical means is as follows.

If the differential pressure between the condenser pressure and the evaporator pressure, or the condenser pressure itself is below the specified value, the vane opening in the air volume adjustment mechanism after startup is set to the minimum vane opening that can be throttled (surge cut). (opening) to force a stop. On the other hand, when the differential pressure or the condenser pressure reaches the specified value, the forced stop operation of the vane opening is canceled and the vane damper control is switched to normal temperature controller output. This makes it possible to suppress the amount of refrigerant liquid that accumulates in the condenser at the time of startup, so that the evaporation pressure does not drop abnormally at the time of startup.

[Example 1] An example of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a schematic configuration diagram of a centrifugal chiller according to an embodiment of the present invention, FIG. 2 is a wiring diagram of the control circuit of the actuator section in FIG. 1, and FIG. 3 is a limit diagram in FIG. 2. FIG. 3 is an explanatory diagram of the operation of the switch. In FIG. 1, parts with the same reference numerals as in FIG. 4 are equivalent to those in the prior art, so their explanation will be omitted.

The turbo compressor of this embodiment shown in FIG. This is to detect the differential pressure with the evaporator 4.

In addition, the actuator 6 constituting the air volume regulator a7 is equipped with a limit switch 11 (T, 3 in Fig. 2) that is turned on at the minimum throttling opening of the refrigeration capacity, that is, the lowest vane opening that can be throttled (surge cut opening). is provided.

Furthermore, as shown in FIG. 2, the electric circuit for operating the actuator 6 is provided with an auxiliary relay 12 for amplifying the signal of the limit switch 11.

On the other hand, the contact 13 of the differential pressure switch 10 is on the input signal circuit that operates the actuator 6 to increase the air volume.
and the contacts 14 of the auxiliary relay 12 are arranged in parallel.

In FIG. 2, Ll is an open switch for the vane 5 drive circuit related to the aperture mechanism, and L2 is a close switch for the vane 5 drive circuit, which constitutes a surging prevention interlock circuit.

The operation of the centrifugal refrigerator of this embodiment will be explained.

When the centrifugal chiller is started under conditions of low cooling water temperature or low outside air temperature, since the cold water temperature is higher than the planned value at the time of startup, a signal to increase the air volume is input to the electric circuit. At this time, since the differential pressure switch 10 has not reached the specified value, the contact 13 is disconnected. on the other hand.

Operation chart 1-1 of limit switch 11 shown in FIG.
5, the limit switch 11 (L3) is in an OFF state until the vane 5 reaches the minimum throttle opening (surge cut). Therefore, since the contacts 14 of the auxiliary relay 12 are energized, the actuator 6 is connected to the vane 5.
It operates so that it opens.

Next, when the opening degree of the vane 5 reaches the minimum throttle opening degree, the limit switch 1.1 (L3) turns ON (energized state), so the contact 14 of the auxiliary relay 12 is cut off, and the open side switch of the vane 5 is turned on. L1 goes OF'F.

At this time, if the differential pressure switch 10 is not operating, even if a signal to increase the air volume is input to the electric circuit, the contact 13
．． 14 remains disconnected, the actuator 6 maintains a stopped state.

Next, as the cooling water temperature rises, the condenser 2 and evaporator 4
When the differential pressure increases and reaches a specified differential pressure, the differential pressure switch 10 is activated and the contact 13 becomes energized. In this way, a signal is inputted to the actuator 6 to open the vane 5 again, and the opening switch L1 is turned on.

According to this embodiment, in a centrifugal chiller used for annual operation, even if the outside air condition before startup is low, it is possible to prevent abnormal liquid from accumulating in the condenser at the time of startup.

In the above embodiment, a differential pressure switch 10 that detects the differential pressure between the condenser 2 and the evaporator 4 is used as the pressure detection stage f, but a pressure detector that detects only the pressure of the condenser 2 is used. Similar effects can be obtained by using .

Further, although not specifically illustrated or explained, a timer related to a timer is provided in place of the differential pressure switch 10 (pressure detection means) in the above embodiment, and within a certain specified time after startup, the minimum throttle opening is After the vane has opened to a certain degree, the actuator is stopped at that opening degree, in other words, the actuator is forcibly stopped at an opening degree corresponding to the minimum capacity, and the forced stop is canceled after a specified time preset by the timer has elapsed. There is no problem.

In this case as well, the same effects as in the previous embodiment are expected.

[Effects of the Invention] As described above, according to the present invention, even if the outside air conditions before startup are low, abnormal liquid accumulation in the condenser at startup is prevented, and stable operating conditions are maintained throughout the year. It is possible to provide operation control Mfi of the centrifugal chiller for

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a centrifugal chiller according to an embodiment of the present invention, FIG. 2 is a wiring diagram of the control circuit of the actuator section in FIG. 1, and FIG. 3 is a limit diagram in FIG. 2. Explanation of switch operation FIG. 5 is a schematic configuration diagram of a conventional centrifugal chiller. 1... Compressor, 2... Condenser, 4... Evaporator, 5
... Vane, 6... Actuator, 7... Air volume adjustment mechanism. 8...Temperature controller, 9...Cold water pipe system, 10...Differential pressure switch, 11...Limit switch, 13.14.
··contact.

Claims (1)

[Claims] 1. A turbo chiller comprising a turbo compressor, a condenser, and an evaporator equipped with an air volume adjustment mechanism, the air volume adjustment mechanism being controlled by the temperature of a cold water system flowing through the evaporator. The operation control device includes a pressure detection means connected to the condenser and the evaporator, and a limit switch means located in the actuator section of the air volume adjustment mechanism and turned on at the minimum throttle opening position of the refrigeration capacity, and starts. At times, after the throttle mechanism opens to the minimum throttle opening, the air volume adjustment mechanism is stopped at that opening, and when the detected value of the pressure detection means exceeds a specified value, the opening of the air volume adjustment mechanism is stopped. 1. An operation control device for a centrifugal chiller, characterized in that a control circuit is configured to release the . 2. In an operation control device for a turbo chiller, which is composed of a turbo compressor, a condenser, and an evaporator and is equipped with an air volume adjustment mechanism, the air volume adjustment mechanism is controlled according to the temperature of the cold water system flowing through the evaporator. and a limit switch means which is located in the actuator section of the air volume adjustment mechanism and turns ON at a minimum throttle opening position of the refrigeration capacity, and the throttle mechanism is turned on to the minimum throttle opening within a certain specified time at the time of startup. A centrifugal chiller characterized in that a control circuit is configured to stop the air volume adjustment mechanism at the opening degree after the opening of the air volume adjustment mechanism is opened, and to release the stoppage of the opening degree of the air volume adjustment mechanism after a predetermined time has elapsed. Operation control device.