JPS5899811A - Temperature controller of turbo-refrigerating machine - Google Patents

Abstract

PURPOSE:To execute an automatic operation without overshoot from the time of start of its operation, by utilizing the fact that an inlet vane opening of a compressor in case when a temperature of a cooling water outlet has reached a set value becomes a function of a temperature of a cooling water inlet. CONSTITUTION:As for a temperature controller provided on a cooling water outlet 6, an integral control action separation type PID temperature controller 10 is used. Also, at the time of integral control action separation, the reset rate of the integral control action is set so as to become an optimum vane opening (an inlet vane opening of a compressor 2) corresponding to a temperature of a cooling water inlet, by an output of a function generator 9. Subsequently, when a temperature of the cooling water outlet 6 has reached a set value, an integral control action separating contact 11 is closed, and the temperature controller 10 is set to an integral control action turn-on state. In this case, since the reset rate of the integral control action is set to an optimum value in advance by an output of the function generator 9, the vane opening in case when the integral control action has been turned on becomes an optimum value. In this way, the automatic operation can be executed without overshoot from the time of start of its operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control device for a centrifugal chiller, and relates to a temperature control device for a centrifugal chiller that is suitable for enabling automatic operation without overshoot from the start of operation. be.

Figure 1 is a 41 diagram of a conventional centrifugal refrigerator, in which the refrigerant is gasified in the evaporator 1, and this gasified refrigerant is transferred to the compressor 2.
is sucked into and compressed. Next, this compressed gasified refrigerant is sent to #@ container 3, where it is cooled and liquefied. This liquefied refrigerant is sent to the economizer 4 where it is pressurized and reduced in temperature, and then sent again to the evaporator 1 where it is gasified. That is, the refrigerant sequentially repeats the four processes of evaporation, compression, condensation, and coercion in the refrigerator, and the latent heat of vaporization in the evaporation process cools the supply water supplied from the cold water inlet 5, and the water flows out from the cold water outlet 6. Go. By the way, the boiling temperature of the refrigerant at this time is uniquely determined by the pressure inside the evaporator 1, so the inlet opening f of the pressurizer 2 is adjusted by the setting meter 7 at the cold water outlet 6. The temperature of the cold water is controlled by controlling the suction amount of the compressor 2, that is, the internal pressure of the evaporator 1. However, when controlling the chilled water outlet temperature in this way, the chilled water outlet temperature is higher than the set value.
In Takanawa, a serious accident occurs when the evaporator l freezes due to oversineating when the set value is exceeded and the temperature drops below the set value. Therefore, in order to prevent this from happening, manual operation is performed until the chilled water outlet temperature is cooled to a set value, and once the set value is reached, operation is switched to automatic operation. Number nine, which is extremely inconvenient for operation, is the compressor drive device.

The present invention has been made in view of the above, and an object of the present invention is to provide a temperature control device for a centrifugal chiller that can automatically operate the centrifugal chiller without overshoot from the time the centrifugal chiller starts operating.

The present invention was made by focusing on the fact that the opening degree of the compressor type lobby 7 (output signal of the degree controller) when the chilled water outlet temperature of the centrifugal chiller reaches the set point is a function of the chilled water inlet temperature. This is the cold water outlet of the centrifugal chiller! The temperature control needle that operates at 150°C is an integral action separated type PIDeA pointer, and when the integral action is separated, the reset rate of the integral action is determined by the output of a function generator that takes the chilled water inlet temperature signal as input, and when the integral action is turned on, the compressor inlet The temperature controller is configured to close the integral operation separation contact and enter the integral operation when the chilled water outlet temperature reaches the set value. #I'm sober.

The present invention will be explained in detail below using Example 2 shown in FIG. 2 and FIG. 3.

FIG. 2 is a block diagram showing an embodiment of a centrifugal chiller equipped with a temperature control device according to the present invention. The same parts as in FIG. In FIG. 2, the chilled water inlet temperature (supply water temperature at chilled water population 5) is extracted as a signal and used as an input signal to the function generator 9, and the function generator 9 calculates the optimum vane opening corresponding to the chilled water inlet temperature. I am trying to calculate. The temperature control needle provided at the cold water outlet 6 is an integral action separated type PID temperature controller lO, and the reset rate when the integral action is separated is set by the output of the function generator 9 so that it becomes a function of the cold water inlet temperature. That's what I do. Note that the optimum vane opening degree (inlet vane opening degree of the compressor 2) corresponding to the cold water inlet temperature is uniquely determined by the refrigerating capacity of the refrigerator, and is generally determined by the third
As shown in the figure, the output of the function generator 9 is calculated on the assumption that the relationship between the chilled water outlet @ degree and the optimum vane opening degree, that is, the optimum reset rate of the integral operation of the temperature control needle is a linear curve. .

Next, the operation will be explained. From the start of the centrifugal chiller until the chilled water outlet temperature (chilled water temperature at the chilled water outlet 6) reaches the set value, the temperature controller 10 operates with the integral operation separated, and when the integral operation is separated, the reset rate of the integral operation is changed. is set to be the optimum vane opening corresponding to the chilled water inlet temperature by the output of the function generator 9, and if the chilled water outlet temperature differs from the set value, the integral operation separation contact 11t- is set according to the chilled water temperature detection output. Close the circuit and send the external signal ft
This is applied to the temperature controller 10 to put the temperature controller 10 into the integral operation state. At this time, the reset rate of the integral operation is set to the optimum value by the output of the function generator 9, so the vane once when the integral operation is turned on becomes the optimum value, and from then on, the reset rate is set smoothly without overshoot. Temperature controlled to value.

As explained above, according to the present invention, there is an effect that automatic operation can be performed without overshooting when the temperature reaches a set value from the start of operation of the centrifugal chiller.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional centrifugal chiller, Fig. 2 is a block diagram showing an embodiment of a centrifugal chiller equipped with a temperature control device according to the present invention, and Fig. 3 is a diagram showing chilled water inlet temperature and temperature controller. FIG. 3 is a diagram showing the relationship between the integral operation and the optimal reset rate. 1... Evaporator, 2... Compressor, 3... Condenser, 4
...Economizer, 5...Cooling inlet, 6...Cold water outlet, 9...Function generator, 10...Integral action separate PID temperature control unit -// Male, 3 Figure Chilled water inlet temperature ('c)

Claims (1)

[Scope of Claims] 1. A temperature control device for a centrifugal chiller configured to control chiller cold water outlet temperature by adjusting compressor artificial vane opening according to load, wherein Integral action separated type PID that takes temperature signal as input
@R114 moderator, an integral action separation contact that closes when the chilled water outlet temperature of the refrigerator reaches a set value and inputs the separated integral action of the crystallinity adjustment needle; a function generator that receives a cold water inlet temperature signal as input and sets a reset rate of the integral operation of the temperature control needle while the integral operation is separated to a value that optimizes the opening degree of the compressor artificial vane when the integral operation is started; A temperature control device for a centrifugal chiller, characterized by the following.