JPH0748032B2 - Cooling system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cooling device that cools a fluid to be cooled returning from a device to be cooled and then sends the cooled fluid to the device, and more specifically, can occur in a cooling tower of a cooling device. The present invention relates to a cooling device that prevents heating of a fluid to be cooled.

[Prior Art] Production lines and research facilities for precision equipment require cooling water that is close to the room temperature and has a stable temperature. However, by cooling the fluid to be cooled returning from the equipment to be cooled, Conventionally, a closed cooling tower or a compression chiller has been used as a cooling device for sending out to equipment. With these cooling devices, for example, in a closed cooling tower, it is possible to cool the temperature to about 30 ° C at most in the summer, etc., and it is impossible to cool the fluid to be cooled to a temperature in the middle or lower range than that required for precision equipment. There was a problem. In addition, the compression chiller is cooled to about 7 to 17 ° C and is liable to cause dew condensation due to overcooling, which is not preferable for quality control, and it is difficult to maintain a constant temperature of the fluid to be cooled and there is a problem in maintaining dimensional accuracy. .

Therefore, as a cooling device capable of maintaining a constant temperature in the middle to low temperature range of about 18 to 29 ° C., an air-cooling type cooling tower having a heat transfer pipe and a fan for blowing the heat transfer pipe, a compressor, a condenser and an expansion device. A cooling device provided with a chiller having a valve, an evaporator, and a refrigerant that circulates these, and a pipe line for guiding the cooled fluid returning from the equipment to be cooled to the cooling tower and the evaporator and then sending the fluid to the equipment. , A cooling device has been proposed in which the above cooling tower is an evaporative cooling tower having a water sprinkling mechanism.
61-84480).

[Problems to be Solved by the Invention] The cooling device described above is a cooling device that can maintain a constant temperature in the middle to low temperature range of about 18 to 29 ° C. and that prevents unnecessary overcooling. When using an air-cooling type cooling tower, the temperature of the cooled fluid entering the cooling tower is lower than the outside air dry bulb temperature, and when using the evaporative cooling tower as a cooling tower, the temperature of the cooling fluid entering the cooling tower is outside air humidity. When the temperature is lower than the sphere temperature, the fluid to be cooled is not cooled by the passage of the cooling tower, but rather is heated, and the cooling in the chiller must be unnecessarily large, which deteriorates the efficiency of the entire device. It was

Therefore, the present invention provides a cooling device which can prevent heating of a fluid to be cooled which may occur in a cooling tower, can stably control a cooling tower in a front stage and a chiller in a rear stage, and has a low operating cost. With the goal.

[Means for Solving the Problems] The present invention has been made to solve the above problems, that is, claim 1 of the present invention has a heat transfer pipe and a fan for blowing air to the heat transfer pipe. A cooling tower, a chiller having a compressor, a condenser, an expansion valve, an evaporator, and a refrigerant that circulates them, and a device to be cooled, which is to be cooled, is guided to the cooling tower and the evaporator in this order, and then the device. In a cooling device provided with a pipeline to be sent to the cooling tower, a bypass pipeline bypassing the cooling tower and a switching means for switching between the bypass pipeline and the pipeline passing through the cooling tower are attached, When the temperature difference obtained by subtracting the outside air dry-bulb temperature from the inlet temperature is larger than a predetermined value, the pipeline passing through the cooling tower is opened and the bypass pipeline is closed, and when the temperature difference is smaller than the predetermined value, cooling is performed. Bypass with the pipeline passing through the tower closed When the switching means is controlled to open the pipe, and the temperature of the fluid to be cooled returning to the device is higher than the set temperature range, the cooling capacity of the cooling tower is first increased, and the set temperature range is still set. When the temperature of the fluid to be cooled returning to the device is lower than the set temperature range, the cooling capacity of the chiller is first decreased, and when the temperature is lower than the set temperature range. Is a cooling device in which the cooling tower and the chiller are controlled so as to reduce the cooling capacity of the cooling tower. The temperature difference and the comparison of the temperature difference and the predetermined value are values in which a negative sign is also taken into consideration and do not mean absolute values.

According to a second aspect of the present invention, the cooling tower in the cooling device is an evaporative cooling tower having a mechanism for spraying heat to the heat transfer pipe, and the switching means is based on a value obtained by subtracting the outside air wet bulb temperature from the cooling tower inlet temperature of the fluid to be cooled. This is a cooling device that switches between.

A third aspect of the present invention is the cooling device according to the first or second aspect, wherein the condenser is cooled by the cooling tower.

[Operation] When the cooling tower inlet temperature of the cooled fluid is higher than the outside air dry-bulb or wet-bulb temperature, the cooling fluid passes through the cooling tower and is cooled in the cooling tower. When the temperature is lower than the outside air dry bulb or wet bulb temperature, the fluid to be cooled passes through the bypass line and is not heated in the cooling tower.

When the cooling tower inlet temperature of the cooled fluid is certainly higher than the outside air dry-bulb or wet-bulb temperature but only slightly higher, the cooling temperature is lower than the cooling amount of the cooled fluid obtained by passing through the cooling tower. Since the pressure loss caused by passing through the tower and the loss caused by operating the fan or the water sprinkling mechanism are larger, the predetermined value does not necessarily have to be 0 ° C., and may be a small positive temperature, for example. .

Moreover, since the cooling tower in the first stage and the chiller in the second stage are integrally controlled based on only the temperature of the cooled fluid returning to the equipment, it is possible to stably control these cooling tower and chiller, and Since the cooling tower with low operating cost is operated with priority over the chiller with high operating cost, the operating cost of this cooling device is low.

[Embodiment] An embodiment of the present invention will be described with reference to the accompanying drawings. First
FIG. 1 is a system diagram of an embodiment of a cooling device of the present invention, in which a cooling tower 1 has a plurality of layers of heat transfer pipes 2 and a fan 3, the fan 3 is driven by a motor 4, and an air intake port 5 is provided. The air sucked from the air is sent to the heat transfer pipe 2 to cool it. The chiller 10 includes a compressor 11, a condenser 12, an expansion valve 13 and an evaporator.
The refrigerant is circulated in the chiller 10, the refrigerant is compressed in the compressor 11, liquefied in the condenser 12 to radiate heat, and is evaporated in the evaporator 14 via the expansion valve 13 to absorb heat. Repeat the cycle.

On the other hand, the fluid to be cooled returned from the device 20 to be cooled is the booster pump 21, the first valve 25, the heat transfer pipe 2 of the cooling tower 1,
The second valve 26 and the evaporator 14 are introduced in this order, and finally the circulation pump.
A bypass having a third valve 27 between the upstream side of the first valve 25 and the downstream side of the second valve 26, in addition to being configured so as to be sent to the device 20 via 22. It is short-circuited by a pipe 28, and a temperature detector is provided on the upstream side of the cooling tower 1.
29 is installed. In the drawing, cooling tower 1, chiller
Although only one system is shown for the inflow and outflow pipes to the device 10 and the device 20, all or a part of them may be configured by a plurality of systems. The chiller 10 shown in the drawing is one compressor 11
However, it may be a chiller having a plurality of compressors.

Regarding the operation of the cooling tower 1 and the chiller 10, when the temperature of the temperature detector 23 attached to the outlet of the evaporator 14 for the fluid to be cooled becomes higher than the set temperature range, first, the air flow rate of the fan 3 is increased. When the temperature of the temperature detector 23 becomes higher than the set temperature range, the number of operating compressors 11 is further increased, and when the temperature of the temperature detector 23 becomes lower than the set temperature range, On the contrary, first, the number of operating compressors 11 is reduced, and when the temperature of the temperature detector 23 is still lower than the set temperature range, the amount of air blown by the fan 3 is further reduced.

In this embodiment, however, the temperature detector 29 detects the inlet temperature of the fluid to be cooled into the cooling tower 1, and the dry-bulb temperature detector (not shown) detects the outside air dry-bulb temperature. When the temperature difference obtained by subtracting is larger than a predetermined value, the first and second valves 25 and 26 are opened and the third valve 27 is closed, and when the temperature difference is smaller than the predetermined value. Means that the first and second valves 25 and 26 are closed and the third
The valve 27 is controlled to open. Therefore, by setting the predetermined value so that passing through the cooling tower 1 maximizes the efficiency of the entire apparatus, unnecessary heating by the cooling tower 1 and unnecessary energy loss due to operating the cooling tower 1 are prevented. Can be removed.

Either one of the first and second valves 25, 26 can be omitted, and the first, second and third valves 25, 26, 27 and the bypass line 28 are three-way valves, It may be configured by other means such as a four-way valve.

Next, as shown in FIG. 2, in addition to the heat transfer pipe 2 and the fan 3, the cooling tower 1 is provided with a sprinkler header 6 mounted above the heat transfer pipe 2 and a receiver mounted below the heat transfer pipe 2. Aquarium 7
And a water sprinkling pump 8 for supplying the water in the water receiving tank 7 to the water sprinkling header 6 to form an evaporative cooling tower, and a wet bulb temperature detector is used in place of the dry bulb temperature detector. The same control as above may be performed based on the temperature difference obtained by subtracting the outside air wet bulb temperature from the inlet temperature of the cooling target fluid into the cooling tower 1 by the temperature detector 29.

In the above-mentioned embodiment, if the condenser 12 is cooled in the cooling tower 1, the whole apparatus can be made compact. Second
The figure shows such a configuration. Further, the condenser 12 may be configured by a water-cooled condenser, and at that time, a cooling mechanism for cooling the water-cooled condenser may be installed separately from the cooling tower 1 or may be cooled in the cooling tower 1. Good.

[Effect of the Invention] In the cooling device of claim 1 or 2, in a cooling device in which a closed cooling tower and a compression chiller are efficiently combined, the outside air dry-bulb or wet-bulb temperature is changed from the cooling tower inlet temperature of the fluid to be cooled. When the reduced temperature difference is larger than the predetermined value, the fluid to be cooled passes through the cooling tower, and when the temperature difference is smaller than the predetermined value,
Since the fluid to be cooled is configured not to pass through the cooling tower but to pass through the bypass pipe, heating of the fluid to be cooled that may occur in the cooling tower is prevented, and a cooling device with high energy efficiency is obtained, and It is possible to stably control the cooling tower and the chiller, and to obtain a cooling device with low operating cost.

The cooling device according to the third aspect has the above-mentioned effect and the condenser is incorporated in the cooling tower, so that the entire device becomes compact.

[Brief description of drawings]

1 and 2 are system diagrams of an embodiment of the cooling device of the present invention. 1 ... Cooling tower, 2 ... Heat transfer pipe, 3 ... Fan 4 ... Motor, 5 ... Air intake port 6 ... Sprinkler header, 7 ... Water tank, 8 ... Sprinkler pump 10 ... Chiller, 11 ... Compressor, 12 ... Condenser 13 ... Expansion valve, 14 ... Evaporator, 20 ... Equipment 21 ... Booster pump, 22 ... Circulation pump 23,29 ... Temperature detector, 25, 26, 27 ... Valve 28 ... Bypass line

Claims (3)

[Claims] 1. A cooling tower having a heat transfer pipe and a fan for blowing air to the heat transfer pipe, a chiller having a compressor, a condenser, an expansion valve, an evaporator, and a refrigerant circulating these, and a chiller to be cooled. In a cooling device provided with a pipe for guiding a cooled fluid returning from a device to the cooling tower and an evaporator in this order, and a pipe for bypassing the cooling tower, a bypass pipe bypassing the cooling tower, and the bypass pipe and the cooling device. When the temperature difference between the cooling tower inlet temperature of the fluid to be cooled minus the outside-air dry-bulb temperature is larger than a specified value, the pipeline that passes through the cooling tower is opened. The bypass means is closed, and when the temperature difference is smaller than the predetermined value, the switching means is controlled so that the pipeline passing through the cooling tower is closed and the bypass pipeline is opened; The temperature of the fluid to be cooled returns to the set temperature. When higher than the range, first increase the cooling capacity by the cooling tower,
When the temperature is higher than the set temperature range, the cooling capacity by the chiller is increased, and when the temperature of the fluid to be cooled returning to the device is lower than the set temperature range, first, the cooling capacity by the chiller is decreased, and still. A cooling device, wherein the cooling tower and the chiller are controlled so as to reduce the cooling capacity of the cooling tower when the temperature is lower than the set temperature range. 2. A cooling tower having a heat transfer pipe and a water sprinkling mechanism for watering the heat transfer pipe, a chiller having a compressor, a condenser, an expansion valve, an evaporator, and a refrigerant circulating therein, and a cooling device. In a cooling device provided with a cooling fluid returning from a device to be cooled, a pipe for guiding the fluid to the device in the order of the evaporator, a bypass pipe bypassing the cooling tower, the bypass pipe and the bypass pipe. A means for switching to the pipeline passing through the cooling tower is attached, and when the temperature difference obtained by subtracting the outside air wet bulb temperature from the cooling tower inlet temperature of the fluid to be cooled is larger than a predetermined value, the pipeline passing through the cooling tower is opened. The bypass means is closed, and when the temperature difference is smaller than the predetermined value, the switching means is controlled so that the pipeline passing through the cooling tower is closed and the bypass pipeline is opened, and Set the temperature of the fluid to be cooled back to the device When higher than degree range, first increase the cooling capacity by the cooling tower,
When the temperature is higher than the set temperature range, the cooling capacity by the chiller is increased, and when the temperature of the fluid to be cooled returning to the device is lower than the set temperature range, first, the cooling capacity by the chiller is decreased, and still. A cooling device, wherein the cooling tower and the chiller are controlled so as to reduce the cooling capacity of the cooling tower when the temperature is lower than the set temperature range. 3. The cooling device according to claim 1, wherein the condenser is cooled by the cooling tower.