JPH0735940B2 - Cooling system - Google Patents

Description

The present invention relates to a cooling device that circulates and supplies a liquid refrigerant for cooling a heating element that constitutes an electronic device such as an electronic computer.

[Prior Art] Generally, in an electronic device such as an electronic computer, a large number of printed boards on which a large number of integrated circuits are mounted are mounted in a housing, and forced air cooling is performed by a blower mounted on a rack.

In recent years, due to the adoption of a large-scale integrated circuit and the high-density mounting for realizing a high-speed device, the vaporization density in the device has become high, and these devices often employ a liquid cooling system. FIG. 4 shows the configuration of a conventional cooling system of this type.

In the figure, reference numeral 40 denotes a cooling device and 41 denotes an electronic device which is a cooled object, both of which are connected by a water supply hose 10 and a return hose 11. The electronic device 41 is composed of an LSI 1 which is a heating element, a cooling plate 2 which closely adheres to the LSI 1 and flows a cooling medium inside, and an on-board piping section 3 which connects the cooling plates 2 to each other.

The water supplied from the cooling device 40 passes through the inside of the cooling plate 2 to remove heat, and after the temperature rises, the water is returned to the cooling device 40 where it is cooled and supplied to the electronic device 41 again. .

The cooling device 40 includes a pump 5 for sending water to the electronic device 41, a tank 4, and a water-water heat exchanger 6.
Cooling water 6a having a lower temperature is supplied to the heat exchanger 6 from the outside to cool the water returned from the electronic device 41.

Here, the temperature of the water 12 supplied to the electronic device 41 is controlled by changing the opening of the water amount flowing to the heat exchanger 6 by the three-way valve 7 by rotating the valve motor 8. The rotation angle of the valve motor 8 is determined by the output of the temperature controller 9. This temperature controller 9
The output changes according to the difference between the water temperature sensor 13 provided in the pipe into which water flows in the in-carriage piping part 3 in the electronic device 41 and the temperature sensor 14 provided in the space in the electronic device 41. Is sent to the valve motor 8. Here, the air temperature sensor 14 detects the ambient temperature of the electronic device 41, the temperature of the water 12 is detected by the water temperature sensor 13, and is controlled so as to be kept slightly higher than the ambient temperature. Condensation caused by this is prevented. The output of the temperature controller 9 depends on the proportional / integral / derivative (PID) values set inside, and the reaction is delayed so that the PID value does not change with a slight change in the atmosphere. This is because if the water temperature changes due to a slight change in the atmosphere, the reliability of the LSI 1 may be adversely affected.

[Problems to be Solved by the Invention] However, in the above-described conventional cooling device, when the set value of PID is set so that the tracking is slow, it is effective against a minute change, but when the atmospheric temperature fluctuates rapidly. However, there is a drawback that the water temperature cannot follow and a large difference occurs between the water temperature and the ambient temperature.

FIG. 3 shows the change in water temperature when the ambient temperature changes. In the figure, when the air temperature 45 suddenly rises, the water temperature 46 (broken line in the figure) does not rise rapidly, and it takes time to reach the specified value. At this time, depending on the humidity, dew condensation may occur. If the temperature drops sharply, the water temperature rises for a long time, which is not desirable for the reliability of the LSI.

Furthermore, even when the power supply to a part of the LSI in the electronic device is cut off and the amount of heat generated fluctuates, the adjustment of the cooling capacity does not follow the change in the amount of load, causing a large difference between the water temperature and the air temperature, and the same phenomenon occurs. There is a drawback that.

[Means for Solving the Problems] It is an object of the present invention to solve the above problems and provide a cooling device that can appropriately cool an electronic device by following changes in temperature.

In order to achieve the above object, the cooling device according to the present invention is a cooling device that circulates and supplies a liquid coolant to a cooled object to cool the cooled object, wherein an ambient temperature detecting means for detecting an ambient temperature of the cooled object. A refrigerant temperature detecting means for detecting the temperature of the liquid refrigerant returned from the object to be cooled; and when the ambient temperature detected by the ambient temperature detecting means changes with time, the temperature of the liquid refrigerant is set to the ambient temperature. It is characterized by further comprising temperature control means for adjusting the temperature change rate when controlling to a predetermined temperature determined by the temperature difference detecting means according to the difference between the temperatures detected by the ambient temperature detecting means and the refrigerant temperature detecting means.

That is, the temperature controller, which is the above-mentioned temperature control means, has means for changing a parameter for changing the changing speed of the output signal according to the size of the difference between the temperature of the liquid refrigerant and the ambient temperature, and the changing speed of the control signal is changed by this parameter. In addition, by changing the speed of change of the control signal, the cooling speed control signal realizes the speed of control of the heat dissipation capacity and changes the followability to changes in the ambient temperature of the liquid refrigerant. It is a thing.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a temperature control system of a cooling device according to an embodiment of the present invention. In the figure, the same components as those in FIG. 4 are described with the same reference numerals.

In the figure, 40a is a cooling device, and 411 is an electronic device.
Both devices are connected by a water supply hose 10 and a return hose 11 and circulate a liquid refrigerant (for example, water). Electronic device 41
A large number of LSIs 1 that are heating elements are mounted inside, and are composed of a cooling plate 2 that is in close contact with the LSI 1 and cools the LSI 1 by flowing water from the cooling device 40a into the inside, and an on-board pipe 3 that connects the cooling plates 2. To be done.

On the other hand, the cooling device 40a includes a pump 5, a tank 4, a water-water heat exchanger 6, a three-way valve 7 and a valve motor 8,
The cooling water 6a supplied from the outside cools the water returned from the electronic device 41 by heat exchange. As for the temperature of the water 12 supplied to the electronic device 41, the temperature controller 9a inputs the values of the temperature sensor 14 and the water temperature sensor 13, and the valve motor 8 causes the three-way valve so that the temperature of the water 122 becomes slightly higher than the ambient temperature. It is controlled by changing the opening of 7.

The temperature sensor 14 and the water temperature sensor 13 described above are the same as the positions described in the related art.

Here, the temperature controller 9a of the present embodiment has a function of recognizing the difference ΔT between the water temperature sensor 13 and the temperature sensor 14 and changing the value of PID. A PID value is determined for each size of ΔT, and when ΔT is small, the PID value is set to a value that delays tracking so that the temperature of the water 12 does not change with a slight change in temperature.

On the other hand, when ΔT is large, the value of PID is set to a value at which the response speed becomes fast so that the PID value is immediately followed by the rapid change in the air temperature and the heat generation amount of the electronic device 41.

2A and 2B show the structure of the temperature controller 9a.

In the figure, the values of the water temperature sensor 13 and the temperature sensor 14 are alternately measured by the multiplexer 21, converted into a digital signal by the A / D converter 22, and the CPU 24 through the input port 23.
To enter. The multiplexer 21 is controlled by the CPU 24 via the output port 26. CPU24 is the difference between water temperature and temperature △
T is calculated, and the PID set value is determined by referring to the PID set value table 25a provided in the ROM 25 (FIG. 2 (b)). The PID set value is converted into an analog signal by the D / A converter 27 via the output port 26 and output to the valve motor 8.

The series of operations of the CPU 24 are controlled by the ROM 25. With such temperature control, when the air temperature suddenly rises as shown by the curve 47 in FIG. 3, ΔT increases momentarily and the temperature controller 9a recognizes ΔT and changes the set value of PID. Then, an output to be immediately followed is sent to the valve motor 8, and the three-way valve 7 increases the bypass amount to raise the water temperature as shown by a curve 47. Therefore, the time during which the difference between the air temperature and the water temperature becomes large can be short, and the water temperature can almost follow the changes in the air temperature.

Further, even when the air temperature decreases, the PID set value is changed to reduce the bypass amount to follow the air temperature, and as shown by the curve 47, the time in which the water temperature becomes high is short.

In this embodiment, the set value of the PID is set to four kinds as shown in FIG. 2 (b), but it is not limited to this and any kind may be used, and the more kinds, the better the controllability.

[Effects of the Invention] As described above, the cooling device according to the present invention controls the heat exchanger according to the difference between the ambient temperature of the object to be cooled and the temperature of the liquid refrigerant returned from the object to be cooled, thereby varying the temperature. Since the liquid refrigerant can be cooled by following the above, the difference between the ambient temperature and the liquid refrigerant does not increase. Therefore, the time when the water temperature becomes lower than the air temperature can be extremely shortened, which is effective in preventing dew condensation. In addition, since the time when the temperature is higher than the temperature can be shortened, the reliability of the LSI of the cooled object such as the electronic device is not affected.

Furthermore, even if the amount of heat generated by the electronic device fluctuates, the cooling capacity immediately follows and changes, so the water temperature has the effect of immediately following it, and the problem of condensation described above and the fact that the water temperature remains high Absent. In this way, the water temperature does not fluctuate with respect to the conventional minute fluctuations of the air temperature despite the quick follow-up performance, so that a highly reliable cooling system can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a cooling device according to an embodiment of the present invention, FIG. 2 (a) is a block diagram showing the configuration of the temperature controller shown in FIG. 1, and FIG. 2 (b) is a PID value. FIG. 3 is a diagram showing a setting table, FIG. 3 is a diagram showing a change state of water temperature, and FIG. 4 is a diagram showing a configuration of a conventional cooling device. 1: LSI, 2: Cooling plate 3: In-line piping, 4: Tank 5: Pump, 6: Heat exchanger 7: Three-way valve, 8: Valve motor 9,9a: Temperature controller, 10: Water supply hose 11: Return Hose, 13: Water temperature sensor, 14: Temperature sensor 40, 40a: Cooling device, 41: Electronic device

Claims (1)

[Claims] 1. A cooling device that circulates and supplies a liquid coolant to an object to be cooled to cool the object to be cooled, and an ambient temperature detecting means for detecting an ambient temperature of the object to be cooled; Refrigerant temperature detecting means for detecting the temperature of the liquid refrigerant, when the ambient temperature detected by the ambient temperature detecting means changes with time, when controlling the temperature of the liquid refrigerant to a predetermined temperature determined by the ambient temperature A cooling device comprising temperature control means for adjusting a temperature change rate according to a difference between temperatures detected by the ambient temperature detection means and the refrigerant temperature detection means.