JPH08193754A - Control system for cooler device - Google Patents

Abstract

PURPOSE: To prevent a cooling water temperature from being overshot and to cause it to reach a set temperature within a short period of time by a method wherein a timing for operating a compressor is calculated and determined in reference to a temperature signal, a flow rate signal and a cooling capability of the compressor taken into a control device. CONSTITUTION: Cooling water temperatures detected by temperature sensors 7, 8 and a cooling water flow rate detected by a flow rate sensor 9 are taken into a control device 10. A temperature gradient of cooling water at a water feeding port is calculated for every specified sampling time by applying a temperature value taken from the control device 10 and the temperature sensor 8. The control device 10 calculates a heating amount variation value of load for every specified sampling time in accordance with a predetermined calculating equation under application of the taken signal In addition, an operating command is given to a compressor 2 in the most-suitable timing under application of a discriminating constant, a control constant, a set temperature and the present cooling water temperature got through the calculated value. In this way, the cooling water temperature just after operation of the compressor 2 is prevented from being overshot and the temperature is set to the set temperature in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system control system.

[0002]

2. Description of the Related Art As a conventional technique, Japanese Patent Application Laid-Open No. 3-51653 describes that a control temperature setting machine issues an operation signal to a refrigerator.

[0003]

When the cooling water temperature falls below a certain constant temperature due to the fluctuation of the load calorific value, the compressor is stopped, and when the cooling water temperature rises above a certain constant temperature, the function of operating the compressor is provided. In the cooling device having the above, the constant temperature at which the compressor is operated is generally a set temperature or a set temperature or higher. Even with a cooling device that uses a compressor with variable capacity, immediately after the compressor is operated, the compressor is operated with constant capacity for a certain fixed time in order to stabilize the refrigeration cycle (hereinafter, start control Then, from the time when the start control is completed, the capacity of the compressor is varied to control the cooling water temperature to the set temperature. Therefore, the temperature of the cooling water immediately after the operation of the compressor overshoots the set temperature. This tendency may continue for several tens of seconds or several minutes, although it varies depending on the load heat generation fluctuation amount and the amount of cooling water retained.

An object of the present invention is to perform control to prevent the overshoot of the cooling water temperature immediately after the compressor of the cooling device is operated and to start the operation of the compressor at an optimum timing so as to reach the set temperature in a short time. To provide a method.

[0005]

In the control system for a cooling device of the present invention, a temperature sensor for detecting the temperature of the cooling water and a flow rate sensor for detecting the flow rate of the cooling water are respectively provided at the cooling water feeding outlet and the inlet of the cooling device. Is provided and the signals detected by them are taken into the control device. Further, the control device calculates the temperature gradient of the cooling water supply inlet and the heat generation fluctuation amount of the load by using the set temperature and the captured signal, and the timing for operating the compressor depending on the result and the cooling capacity in the start control. It is achieved by having the function of determining

[0006]

In the control system of the present invention, the timing for operating the compressor is calculated and determined based on the temperature signal, the flow rate signal, and the cooling capacity of the compressor, which are taken into the control device. Accordingly, it is possible to perform control such that the cooling water temperature does not overshoot immediately after the compressor is operated and the temperature reaches the set temperature in a short time.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a cooling device 1 comprises a compressor 2, a condenser 3, an expansion valve 4, an evaporator 5, a pump 6 for circulating cooling water, and a load, which have variable capacities for heat exchange by a refrigeration cycle. 11, a temperature sensor 7 for detecting the temperature of the cooling water to be sent to 11, a temperature sensor 8 for detecting the temperature of the cooling water sent from the load 11, a flow sensor 9 for detecting the flow rate of the cooling water to be sent, and temperature sensors 7, 8, It is configured by a control device 10 that takes in a signal from the flow rate sensor 9 and controls the cooling water temperature to a set temperature.

In the present invention, the control device 10 takes in the cooling water temperature detected by the temperature sensors 7 and 8 and the cooling water supply flow rate detected by the flow rate sensor 9. The control device 10 uses the temperature taken in from the temperature sensor 8 and at every constant sampling time Δt, the temperature gradient ΔTw of the cooling water supply inlet.
Calculate / Δt. Since the temperature gradient ΔTw / Δt is determined by the load heat generation fluctuation amount and the cooling water holding water amount, the same temperature gradient ΔTw / Δt may be obtained by combining the different load heat generation fluctuation amount and the cooling water holding water amount. is there. for that reason,
The control device 10 uses the captured signals to calculate the numbers 1 and 2
According to the arithmetic expression shown in (4), the heat generation fluctuation amount ΔQ of the load is calculated at every constant sampling time Δt.

[0009]

[Equation 1]

[0010]

[Equation 2]

This heat generation fluctuation amount ΔQ and temperature gradient ΔTw /
The control constant X is determined according to Table 1 using Δt.

[0012]

[Table 1]

Further, since the cooling capacity in the starting control is known in advance, the judgment constant Y is determined from that. The optimum timing at which the cooling water temperature does not overshoot and reaches the set temperature at the end of the start control by the arithmetic expression shown in Equation 3 using the judgment constant Y, the control constant X, the set temperature, and the current cooling water temperature. If it is determined that it is the optimum timing, the compressor has a function of issuing an operation command.

[0014]

(Equation 3)

After the start control is completed, the capacity of the compressor is changed so that the cooling water temperature becomes the set temperature.

FIG. 2 shows a transition of the cooling water temperature after the compressor is stopped and immediately after the compressor is operated by the conventional control method. When the load capacity increases when the compressor is stopped and the cooling water temperature reaches a certain temperature Twmax at which the compressor operates, the compressor operates (point A). After that, the cooling water temperature overshoots and gradually approaches the set temperature and stabilizes.
Takes time.

On the other hand, FIG. 3 shows the control method of the present invention.
The transition of the cooling water temperature after the compressor is stopped and immediately after the compressor is operated is shown. According to the present invention, as described above, the operation of the compressor is started at the timing when the set water temperature is reached at the end of the start control (point A '). As a result, it is possible to prevent unnecessary overshoot of the cooling water temperature and perform control to reach the set temperature in a short time.

FIG. 4 is a flow chart showing the outline of the control system of the present invention.

[0019]

The effect of the present invention is to prevent the cooling water temperature from overshooting immediately after the operation of the compressor and to bring the temperature to the set temperature in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram of a cooling device according to an embodiment of the present invention.

FIG. 2 is a cooling water temperature characteristic diagram in a conventional control method.

FIG. 3 is a cooling water temperature characteristic diagram in one embodiment of the present invention.

FIG. 4 is a flowchart showing a control system according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Cooling device, 2 ... Compressor, 3 ... Condenser, 4 ... Expansion valve,
5 ... Evaporator, 6 ... Pump, 7, 8 ... Temperature sensor, 9 ... Flow rate sensor, 10 ... Control device, 11 ... Load.

Claims (1)

[Claims] 1. A compressor having a variable capacity, a condenser, an expansion valve,
A temperature signal detected by a temperature sensor that detects the cooling water temperature, which is provided in a cooling device that exchanges heat using a refrigeration cycle formed by an evaporator, and a flow rate sensor that detects the cooling water supply flow rate. A control device that takes in the flow rate signal and controls the cooling water temperature to the set temperature by the taken signal, prevents overshoot of the cooling water temperature immediately after the compressor is running, and reaches the set temperature in a short time. A cooling device control method that has the function of operating the compressor at optimal timing.