JP2003148878A - Closed type cooling tower for free cooling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain effective cooling and the outlet temperature of a target value even in the state of causing a certain degree of icing between a closed type heat exchanger and an outside air intake port of a cooling tower by selecting the quantity of water spray according to a temperature pattern, and controlling the rotating direction of a blower. SOLUTION: When the outlet temperature reaches the target value, the rotation of a blower 25 is stopped for a prescribed time. When the outlet temperature further rises and reaches the upper limit value after the end of the stop time, the rotation of the blower 25 is started in the reverse direction. During the reverse rotating operation of the blower 25, when the outlet temperature suddenly drops to reach the lower limit value and then starts rising, immediately before reaching the vicinity of the target value, the rotation of the blower 25 is stopped for a prescribed time. The blower 25 is then switched over to normal rotating operation. After this, the outlet temperature suddenly drops and reaches the set value. Every time the outlet temperature reaches the target value in association with icing at the closed type heat exchanger 11, the stop, reverse rotation, stop and normal rotation of the blower 25 are repeated as one cycle to maintain the outlet temperature near the target value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a closed cooling tower for free cooling.

[0002]

2. Description of the Related Art Conventionally, when the outside air wet-bulb temperature at the place of installation of the cooling tower is below freezing, the operation of the refrigerator is stopped.
A free cooling method is used in which only the cooling tower is operated to perform cooling. In this free cooling method, as the cooling tower, a closed type is adopted, circulating cooling water containing an antifreeze liquid is allowed to flow in the heat exchange coil, and the amount of sprayed water sprayed to the outer surface of the heat exchange coil is controlled. Cooling water with a predetermined outlet temperature is obtained.

[0003]

Even when the antifreeze solution is used, freezing of the sprayed water may occur when the outside air wet-bulb temperature is below freezing. As the freezing progresses, the amount of ventilation decreases and the cooling The water outlet temperature tends to rise, which hinders the continuous operation of the cooling tower and the desired cooling performance. In the present invention, in the free cooling, the cooling is effectively performed by controlling the rotation speed of the blower and the forward and reverse rotations thereof, and some freezing is generated between the outside air intake port of the cooling tower and the closed heat exchanger. An object of the present invention is to provide a closed cooling tower that can obtain circulating cooling water having a predetermined outlet temperature even in a state.

[0004]

In order to solve the above-mentioned problems, the specified invention is provided with a hermetically-sealed heat exchanger, in which the hermetically-sealed heat exchanger is sprayed with water from an upper water tank from the hermetically-sealed heat exchanger. Circulating cooling water obtained by operating the cooling tower only when the outside air wet-bulb temperature at the installation location of the closed cooling tower that indirectly cools the circulating cooling water flowing inside stops the operation of the refrigerator and operates only the cooling tower. In a closed cooling tower used for free cooling to obtain cold water using, a temperature sensor for detecting the inlet temperature of the circulating cooling water system and a temperature sensor for detecting the outlet temperature of the circulating cooling water system are provided, In order to obtain the outside air wet-bulb temperature at the installation location of the cooling tower, a relative hygrometer for measuring the relative humidity near the outside air intake portion of the cooling tower and a thermometer for measuring the dry-bulb temperature are respectively installed, and the cooling The motor of the blower provided at the exhaust port of is of a variable speed control type, and the rotation direction thereof can be rotated in the forward and reverse directions, and the spray water is sprayed from the upper water tank in the cooling tower onto the sealed heat exchanger. The motor of the circulation pump arranged in the water system is of a constant rotational speed type, and at least the temperature sensor, a relative hygrometer, and a data calculation unit electrically connected to input the measured value by the thermometer. Is provided, and the data calculation unit has a set value of the outlet temperature of the cooling tower in the vicinity of the freezing point of the wet-bulb temperature at the installation location of the cooling tower, and the exit temperature of the outlet temperature at this set value as a boundary. An upper limit value, a lower limit value, and a temperature setting unit for setting a target value slightly higher than the set value are provided, and the data calculation unit further includes a time table of the rotation direction of the blower according to the outlet temperature. Preset settings Part is is provided with,
This data calculation unit controls the rotation speed of the motor of the blower based on the outlet temperature and the rotation direction is positive according to the time table set in the setting unit,
A cooling tower for free cooling is characterized in that a control unit for reverse rotation control is electrically connected to the data calculation unit and the motor drive control circuit.

In order to solve the above problems, the related invention is
A closed type heat exchanger is provided, and at the installation location of a closed type cooling tower that indirectly cools the circulating cooling water flowing in the closed type heat exchanger by the sprayed water from the closed type heat exchanger from the upper water tank. In a closed cooling tower used for free cooling to obtain cold water by using the circulating cooling water obtained by operating the cooling tower only when the outside air wet-bulb temperature is below freezing and operating the refrigerator. A temperature sensor for detecting the inlet temperature of the water system and a temperature sensor for detecting the outlet temperature of the circulating cooling water system are provided, and the outside air of this cooling tower is used to obtain the outside wet-bulb temperature at the place where the cooling tower is installed. A relative hygrometer that measures the relative humidity near the intake part and a thermometer that measures the dry bulb temperature are respectively installed, and the motor of the circulation pump arranged in the spray water system is a variable speed control type, and the cooling tower The air blower motor provided at the air outlet is of a variable speed control type, and its rotation direction can be rotated in the forward and reverse directions, and at least the temperature sensor, the relative hygrometer, and the electric value so that the measured value by the thermometer can be input. Is provided with a data calculation unit connected in a static manner, and the data calculation unit has a set value of the outlet temperature of the cooling tower in the vicinity of the freezing point of the wet bulb temperature at the cooling tower installation location, An upper limit value, a lower limit value, and a temperature setting section for setting a target value slightly higher than the set value are provided with the set value as a boundary,
The data calculation unit further divides the amount of sprayed water sprayed from the upper water tank onto the closed heat exchanger into several stages according to the outside air wet bulb temperature, and the lower the wet bulb temperature is, the lower the wet bulb temperature is. There is a large amount of water, the higher the outside air wet bulb temperature is, the smaller the amount of water is set in a stepwise manner, and the setting unit in which the time table of the rotation direction of the blower according to the outlet temperature is preset. The data calculator controls the rotation speed of the motor of the circulation pump based on the outside-air wet-bulb temperature range by means of this data calculation unit, and the spraying amount of the corresponding section among the spraying rates of the stepwise set sections. The data calculation unit is a control unit that selects the amount of water, controls the rotation speed of the motor of the blower based on the outlet temperature, and controls the rotation direction of the rotation direction according to the timetable set in the setting unit. And each motor It is a cooling tower for free cooling, characterized in that is electrically connected to a drive control circuit.

In order to solve the above-mentioned problems, it is preferable for control that the drive motor of the blower and the drive motor of the cooling water circulation pump in this cooling tower are of the inverter control system based on the outside air wet bulb temperature.

In order to solve the above-mentioned problems, it is desirable in view of the operating efficiency of the cooling tower that the forward rotation time of the blower in the time table of this cooling tower is set longer than the reverse rotation time.

In order to solve the above-mentioned problems, a measuring instrument for measuring the blowing resistance of the drive motor of the blower due to icing in the cooling tower as a load current is provided, and the load current is equal to or more than 80% of the blocking rate due to icing. In the case where the OR signal of the measurement signal in the case of and the measurement signal in the case of exceeding the upper limit value of the outlet temperature is the stop and reverse rotation command signal of the blower, and the load current value is equal to or less than the blockage rate of 40% due to icing It is preferable that the blower rotation direction control circuit that returns the rotation direction of the blower to the normal rotation by a measurement signal and an OR signal of the measurement signal when the outlet temperature is less than the set value is provided.

In order to solve the above-mentioned problems, the drive control circuit of the motor of the circulation pump in this cooling tower, when there is a fluctuation in the outside-air wet-bulb temperature exceeding the outside-air wet-bulb temperature at each stage, In order to prevent the acceleration of freezing, it is desirable to change the water spray amount to a predetermined amount corresponding to the outside air wet bulb temperature.

In order to solve the above-mentioned problems, the control unit in this cooling tower controls the rotation speed of the motor of the blower based on the change of the outlet temperature for each of the sections of the set water spray amount. At the same time, it is preferable that the rotation direction be controlled in the forward / reverse rotation according to the set time table.

In order to solve the above-mentioned problems, the timetable in this cooling tower is such that sprayed water is sprayed on a sealed heat exchanger at a predetermined amount of water, and in this state, the frozen heat is frozen in the sealed heat exchanger. The outlet temperature rises with it, and continues to rotate the blower provided in the cooling tower in the forward rotation until it reaches a target value higher than the set value, and then, when the outlet temperature reaches the target value, the blower Rotation of the blower is stopped for a predetermined time, and after the stop, when the outlet temperature further rises and reaches the upper limit value, the rotation of the blower is started in the reverse direction,
During the reverse rotation operation of the blower, when the outlet temperature suddenly drops and reaches the lower limit value, when it starts to rise and becomes a value slightly lower than the target value, the rotation of the blower is stopped for a predetermined time, then When the outlet temperature reaches the upper limit value, the blower is switched to the normal rotation operation, and thereafter, the outlet temperature sharply decreases, and after reaching the set value, the outlet is accompanied by the freezing in the sealed heat exchanger. It is desirable that the blower is reversely rotated in the same manner as described above each time the temperature reaches the target value.

In order to solve the above-mentioned problems, the time table in this cooling tower is such that the amount of the sprayed water sprayed from the upper water tank onto the closed heat exchanger is changed in several stages according to the wet bulb temperature. The lower the wet bulb temperature, the greater the amount of water,
The higher the wet-bulb temperature, the smaller the amount of water is preset in advance, and in the wet-bulb temperature range within each of the single sections, the sealed heat exchanger is maintained in the state where the preset amount of water is maintained. The outlet temperature rises due to freezing in, until the target value higher than the set value is reached, the blower provided in the cooling tower continues to rotate forward, and then the outlet temperature reaches the target value. Sometimes, the rotation of the blower is stopped for a predetermined time, after the stop, when the outlet temperature further rises and reaches the upper limit value, the rotation of the blower is started in the reverse direction,
During the reverse rotation operation of the blower, when the outlet temperature suddenly drops and reaches the lower limit value, when it starts to rise and becomes a value slightly lower than the target value, the rotation of the blower is stopped for a predetermined time, then After switching the blower to normal rotation operation when the outlet temperature reaches the upper limit value, the outlet temperature sharply decreases, reaches a set value, and then the outlet temperature due to freezing in the sealed heat exchanger. Each time the target value reaches the target value, the blower is reversely rotated in the same manner as described above, which is preferable for continuous operation of the cooling tower.

In order to solve the above problem, a flow meter for measuring the flow rate of the spray water is installed in the return pipe of the spray water system in the cooling tower, and the flow meter is connected to the data calculation unit. It may also be characterized.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 This embodiment is a typical embodiment of a cooling tower for carrying out the invention described in claims 2, 3, 4, 5, 6, 7, 9 and the invention described in claim 10. Is. In FIG. 1, A indicates a closed cooling tower, and a closed heat exchanger 11 is loaded in the cooling tower A below the upper water tank 10. The drop water tank 14 of the lower water tank 13 that receives the circulating cooling water sprinkled on the sealed heat exchanger 11 is a storage tank (not shown) that is connected to an air conditioner without a refrigerator (not shown) during free cooling. Can be selectively communicated with. The circulating cooling water circulating in the heat exchange coil arranged in the tank during the free cooling indirectly contacts the cold water of the air conditioner side stored in the tank, and after cooling it, the closed heat Return to the exchanger 11 and adjust. The spray water supplied to the upper water tank 10 directly contacts the external airflow to indirectly cool the circulating cooling water, and constitutes a spray water system that is circulated and used in the upper water tank 10.

A temperature sensor 15 for detecting the inlet temperature of the circulating cooling water system and a temperature sensor 16 for detecting the outlet temperature of the circulating cooling water system are provided, and the outside-air wet-bulb temperature at the place where the cooling tower A is installed is provided. In order to obtain the temperature, a relative hygrometer 18 for measuring the relative humidity in the vicinity of the outside air intake portion 17 of the cooling tower A and a thermometer 19 for measuring the dry bulb temperature are respectively installed. The temperature sensor 18, the relative hygrometer 19, and a data calculation unit 27 electrically connected to the measurement value by the thermometer 16 are provided. A flow meter 21 for measuring the flow rate of the circulating water is installed in the return pipe 20 of the spray water system. The motor of the circulation pump P arranged in the spray water system is of a type in which the drive is controlled by the inverter circuit 22. However, the invention is not limited to this method.

Further, the outside airflow obtained by cooling the circulating cooling water through direct contact with the circulating cooling water flowing from the outside air intake portion 17 through the closed type heat exchanger 11 and flowing down on the surface of the closed type heat exchanger 11 is provided. The blower 25 for exhausting air from the exhaust port 24 through the mixing chamber 23 to the outside of the cooling tower A is provided with the exhaust port 24.
It is installed in. The motor of the blower 25 is driven and controlled by an inverter circuit 26, and its rotation direction is controlled in forward and reverse directions. At least the temperature sensor 18, a relative hygrometer 19, and a data calculation unit 27 electrically connected to the measurement value of the thermometer 16 are provided. The data calculation unit 27 has a set value of the outlet temperature of the cooling tower A near the freezing point of the wet-bulb temperature at the place where the cooling tower is installed, and the upper and lower limits of the outlet temperature at the set value. The temperature setting part moth is provided for setting a target value and a target value slightly higher than the set value. The data calculation unit 27 is further provided with a setting unit for presetting a time table of the rotation direction of the blower according to the outlet temperature. The data calculator 27 further divides the amount of sprayed water from the upper water tank 10 onto the closed heat exchanger 11 into several stages according to the outside air wet bulb temperature, and the wet bulb temperature is low. The amount of water is increased and the amount of water is increased as the outside air wet bulb temperature is increased, and the amount of water is decreased stepwise, and a time table that determines the rotation direction of the blower 25 according to the outlet temperature is set in advance. This data calculation unit 27
The rotation speed of the motor of the circulation pump P is controlled based on the outside-air wet-bulb temperature range to select the set sprinkling amount, and the rotation speed of the motor of the blower 25 is set based on the outlet temperature. A control unit 28 that controls the rotation direction of the rotation direction according to the set timetable is electrically connected to the data calculation unit 27 and the control circuits 22 and 26.

Preferably, the control unit 28 controls the rotational speed of the motor of the blower 25 based on the change in the outlet temperature for each of the sections of the set water spray amount, and the rotational direction thereof is the above-mentioned. Forward / reverse rotation control is performed according to the set time table. In addition, the timetable divides the amount of sprayed water from the upper water tank 10 onto the closed heat exchanger 11 into several stages according to the wet bulb temperature, and the lower the wet bulb temperature, the larger the amount of water. , The higher the wet-bulb temperature, the smaller the amount of water is preset in stages, and within the wet-bulb temperature range within each of the single sections, the sealed heat exchange is performed while maintaining the preset amount of water sprinkling. The blower 25 provided in the cooling tower A continues to rotate forward until the outlet temperature rises due to freezing in the vessel 11 and reaches a target value higher than the set value. After that, when the outlet temperature reaches the target value, the rotation of the blower 25 is stopped for a predetermined time. After stopping the blower 25, when the outlet temperature further rises and reaches the upper limit value, the rotation of the blower 25 is started in the reverse direction, and the blower 25 is rotating in the reverse direction.
When the outlet temperature suddenly drops and reaches the lower limit value, and then starts to rise and becomes a value slightly lower than the target value, the rotation of the blower 25 is stopped for a predetermined time. Next, when the outlet temperature reaches the upper limit value, the blower 25 is switched to the normal rotation operation, and then the outlet temperature sharply decreases and reaches a set value, and then the outlet is accompanied by freezing in the sealed heat exchanger. Each time the temperature reaches the target value, the blower 25 is reversely rotated in the same manner as described above. The timetable is such that the blower continues normal rotation operation when the outside air wet bulb temperature is in the range of 0 ° C to + 1 ° C.

The operation of the cooling tower A will be described together with the method of using it. When the outside-air wet-bulb temperature at the place where the cooling tower A is installed is near the freezing point,
The upper limit value, the lower limit value and the set value of the outlet temperature of A, and a target value higher than this set value are set in advance. The data calculator 2
According to the time table of 7, the amount of water sprayed from the upper water tank 10 onto the sealed heat exchanger 11 is further divided into several stages according to the wet bulb temperature, and the lower the wet bulb temperature, the more the amount of water. The more the wet bulb temperature is, the smaller the amount of water is, and the amount of water is preset in stages (see FIG. 2). Next, the cooling tower A is operated, and the outside air relative temperature and the dry bulb temperature in the vicinity of the outside air intake section 17 are measured by the hygrometer 18 and the thermometer 1.
9, and these measured values are measured by the data calculation unit 27.
And the outside air wet-bulb temperature is calculated based on these measured values. When the obtained outside air wet bulb temperature is near the freezing point, the operation of the refrigerator is stopped, the cooling tower A is operated, and the free cooling is performed. At this time, according to the timetable, the distribution amount of the sprinkling amount corresponding to the obtained outside air wet bulb temperature is selected from the set several classifications, and the circulation pump P is adjusted so that the sprinkling amount of the selected classification is achieved. A command signal is issued from the control unit 28 to the inverter circuit 22 for use, the frequency of the inverter circuit 22 is changed, the rotation speed of the motor of the circulation pump P is adjusted, and the sprinkling amount of the circulating cooling water is selected. Numerical value. The flow rate of the sprinkling amount after this selection is constantly measured by the flow meter 21, and the variation of the sprinkling amount in the same section is monitored and the inverter circuit 22
Feedback control the frequency of. After selecting the classification and setting the water spray amount to the set value, a command signal is issued from the control unit 28 to the inverter circuit 26 of the blower 25 according to the outlet temperature, and the frequency control of the inverter circuit 26 and the blower 25 are performed. Forward / reverse control is performed as follows.

In the wet bulb temperature range within each of the single sections,
In the state where the water spray amount set respectively in advance is maintained, the outlet temperature rises due to the freezing in the closed heat exchanger 11, and the cooling tower A continues until it reaches a target value higher than the set value. The provided blower 25 is continuously rotated in the normal direction. After this, when the outlet temperature reaches the target value,
The rotation of the blower 25 is stopped for a predetermined time. After the stop time, when the outlet temperature further rises and reaches the upper limit value, the rotation of the blower 25 is started in the reverse direction. During the reverse rotation operation of the blower 25, when the outlet temperature suddenly drops and reaches the lower limit value, and then starts to rise, and becomes a value slightly lower than the target value, the rotation of the blower 25 is stopped for a predetermined time. . Next, when the outlet temperature reaches the upper limit value, the blower 25 is switched to the normal rotation operation. After this,
The outlet temperature drops sharply and reaches a set value. Each time the outlet temperature reaches the target value due to freezing in the closed heat exchanger 11, the blower 25 is stopped, rotated in reverse, stopped, or rotated normally.
Repeated as one cycle to maintain the outlet temperature near the target value.

The forward rotation time of the blower 25 is set longer than the reverse rotation time, and the total time of one cycle is about 20 to 60 minutes. The cooling tower A is operated with the air passage blockage rate due to freezing in the closed heat exchanger 11 being 40% to 80%. That is, the blowing resistance of the drive motor of the blower 25 due to freezing is measured as a load current, and the measurement signal when the load current is equal to or more than the 80% blockage rate due to freezing and the measurement when the outlet temperature exceeds the upper limit value are measured. The signal OR signal serves as a stop and reverse rotation command signal for the drive motor of the blower 25, and the load current causes the blockage rate 40 due to freezing.
The blower 25 is operated by the OR signal of the measurement signal when the value is equal to or less than the% equivalent value and the measurement signal when the value is equal to or less than the set value of the outlet temperature.
Return the drive motor of to normal rotation. Preferably, the outside-air wet-bulb temperature is divided into five stages within a range of −10 ° C. to + 1 ° C., and the watering amount is set to a predetermined value in advance within the outside-air wet-bulb temperature range in each division. When there is a change in the outside-air wet-bulb temperature that exceeds the outside-air wet-bulb temperature at each stage, the amount of water spray is changed to a predetermined water spray amount corresponding to the outside-air wet-bulb temperature at that time. In this way, the outlet temperature of the circulating cooling water is substantially maintained at the set value while avoiding the sealing due to the freezing in the gap between the closed heat exchangers 11 and the outside air intake portion 17 where the outside air wet bulb temperature is near the freezing point. Then, cold water having a desired temperature is supplied to the air conditioner. By changing the amount of water sprinkled, the water sprinkling state in the upper water tank 10 is adjusted, and freezing on the sealed heat exchanger 11 is prevented.

Embodiment 2 This embodiment is a typical embodiment including the inventions described in claims 1, 2, 3, 4, 5, and 8, and when freezing occurs in free cooling different from the first embodiment. The structure of the cooling tower is that the motor of the circulation pump P arranged in the spray water system for spraying spray water from the upper water tank 10 to the closed heat exchanger 11 in the cooling tower A is of constant rotation type, In the outside air wet-bulb temperature range, for example, in the range of -10 ° C to + 1 ° C, the amount of circulating cooling water from the upper water tank 10 onto the closed heat exchanger 11 is kept constant and the circulating cooling water is closed heat. This is because the water is sprinkled on the exchanger 11, and other configurations are the same as those in the first embodiment.

[0022]

According to the first aspect of the invention, the motor of the circulation pump arranged in the spray water system for spraying spray water from the upper water tank to the closed heat exchanger in the cooling tower is of a constant rotation speed type. By controlling the direction of rotation of the blower under a constant amount of sprinkling water, effective cooling is achieved, and the target value is maintained even when there is some icing between the outside air intake of the cooling tower and the closed heat exchanger. The outlet temperature can be obtained. In the inventions according to claims 2, 3, 4, 5, 6, 7, 8, 9, and 10, the amount of water sprayed at the time of the free cooling is selected according to the temperature pattern, and the rotation direction of the blower is controlled. Thus, it is possible to effectively cool and obtain the target outlet temperature even when there is some icing between the outside air intake of the cooling tower and the closed heat exchanger. Further, the range of the outside air wet bulb temperature at which the cooling tower can be operated can be expanded, and this closed cooling tower can be used even in the severe winter regions such as Hokkaido, Tohoku, and Hokuriku.

According to a third aspect of the invention, the drive motor of the blower and the drive motor of the cooling water circulation pump are:
By performing inverter control based on the outside-air wet-bulb temperature, these motors can be reliably controlled in response to a change in the outside-air wet-bulb temperature, and the above-described effect can be more significantly exhibited.

In the invention of claim 4, the forward rotation time of the blower is set longer than the reverse rotation time, so that the original cooling performance of the cooling tower is not deteriorated.
The above effect can be sufficiently exhibited.

In a fifth aspect of the present invention, there is provided a measuring device for measuring the blowing resistance of the drive motor of the blower due to freezing as a load current, and when the load current is equal to or greater than the blockage rate of 80% due to freezing. The OR signal of the measurement signal and the measurement signal when the upper limit value of the outlet temperature is exceeded serves as the stop and reverse rotation command signal of the blower, and the measurement signal and the case when the load current is equal to or less than the 40% equivalent blocking rate due to freezing By providing the blower rotation direction control circuit that returns the rotation direction of the blower to the forward rotation by the OR signal of the measurement signal when the outlet temperature is less than or equal to the set value, the circulating cooling water is accompanied by the thawing of freezing. The above effect can be exhibited in a state where the water is efficiently cooled and icing is allowed to some extent.

In a sixth aspect of the present invention, the drive control circuit for the motor of the circulation pump is configured so that when the outside-air wet-bulb temperature fluctuates exceeding the outside-air wet-bulb temperature at each stage, the outside-air at that time is changed. Since the amount of water spray is changed to a predetermined amount of water spray corresponding to the wet-bulb temperature, the amount of water spray can be appropriately controlled and the above effect can be exhibited.

According to a seventh aspect of the present invention, the control unit controls the rotation speed of the motor of the blower based on the change in the outlet temperature for each of the sections of the set water spray amount. By controlling the direction of rotation in the forward and reverse directions according to the set timetable, it is possible to always obtain a predetermined outlet temperature in free cooling.

In the invention according to claim 8, in the time table, spray water is sprayed on the sealed heat exchanger at a predetermined spray amount, and in this state, the sprayed water accompanies freezing in the sealed heat exchanger. The outlet temperature rises, the fan provided in the cooling tower continues to rotate forward until it reaches a target value higher than the set value, and then, when the outlet temperature reaches the target value, the rotation of the fan is changed. After stopping for a predetermined time, after the stop, when the outlet temperature further rises and reaches the preset upper limit value, the rotation of the blower is started in the reverse direction, and the outlet temperature during the reverse rotation operation of the blower. Abruptly descends and reaches the lower limit value, then starts to rise and becomes a value slightly lower than the target value, the rotation of the blower is stopped for a predetermined time, and then when the outlet temperature reaches the upper limit value. Forward rotation of the blower After that, the outlet temperature sharply decreases, and after reaching the set value, the blower is operated in the same manner as described above each time the outlet temperature reaches the target value due to freezing in the closed heat exchanger. By performing the reverse rotation operation, the effect of the invention according to claim 1, 3, 4, 5, 6 or 7 can be exhibited.

In the invention according to claim 9, the timetable divides the amount of the cooling water sprinkled from the upper water tank onto the sealed heat exchanger into several stages according to the wet bulb temperature. , The lower the wet bulb temperature is, the larger the amount of water is, and the higher the wet bulb temperature is, the smaller the amount of water is set in advance. In the wet bulb temperature range within each of the single divisions, the previously set watering amount is set. In the state of maintaining, the outlet temperature rises due to freezing in the closed heat exchanger, and continues to rotate the blower provided in the cooling tower in the forward rotation until it reaches a target value higher than the set value. When the outlet temperature reaches the target value, the rotation of the blower is stopped for a predetermined time, and after the stop,
When the outlet temperature further rises and reaches the upper limit value, the rotation of the blower is started in the reverse direction, and during the reverse rotation operation of the blower, the outlet temperature sharply decreases and rises after reaching the lower limit value. Then, when the value becomes slightly lower than the target value, the rotation of the blower is stopped for a predetermined time, and when the outlet temperature reaches the upper limit, the blower is switched to the normal rotation operation, and then the outlet temperature is reached. Decreases sharply and reaches the set value. Next, each time the outlet temperature reaches the target value due to freezing in the closed heat exchanger, the blower is reversely rotated in the same manner as described above, whereby the blower is rotated in the reverse direction. In addition to the effects of the invention described in paragraphs 7 and 7, the operable range of the cooling tower below freezing can be expanded. Claim 1
In the invention described in 0, the rotation control of the blower is simplified.

In the invention described in claim 11, a flow meter for measuring the flow rate of the circulating water is installed in the return pipe of the spray water system, and the flow meter is connected to the data calculation section. The effects of the invention described in claim 2, 3, 4, 5, 6, 7 or 9 can be appropriately exhibited.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an entire embodiment.

FIG. 2 is a schematic diagram showing a control pattern of the water spray amount in FIG. 1.

FIG. 3 is a schematic diagram showing an operation pattern of the blower in FIG. 1.

[Explanation of symbols]

25 blower

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuji Kikuchi             Fujisawa City, Kanagawa Prefecture Fujisawa 5-6-8 Stock Association             Ebara Shinwa Fujisawa Factory (72) Inventor Shigenobu Kunichika             4-2-2 Hatchobori, Chuo-ku, Tokyo Co., Ltd.             Inside Ebara Shinwa F term (reference) 3L103 AA31 AA33 CC02 CC22 DD66                       DD67

Claims (11)

[Claims] 1. A closed type cooling tower comprising a closed type heat exchanger, wherein the circulating cooling water flowing in the closed type heat exchanger is indirectly cooled by water sprayed from the closed type heat exchanger from the upper water tank. Closed cooling tower used for free cooling to obtain cold water by using the circulating cooling water obtained by stopping the operation of the refrigerator near the freezing point of the outside air at the installation location of In, with a temperature sensor for detecting the inlet temperature of the circulating cooling water system, and a temperature sensor for detecting the outlet temperature of the circulating cooling water system,
In order to obtain the outside air wet bulb temperature of the installation location of the cooling tower,
A relative hygrometer for measuring the relative humidity near the outside air intake part of the cooling tower and a thermometer for measuring the dry-bulb temperature are respectively installed, and the motor of the blower provided at the exhaust port of the cooling tower is of a variable speed control type. The rotation direction is such that the rotation direction is reversible, and the motor of the circulation pump arranged in the spray water system for spraying spray water from the upper water tank onto the sealed heat exchanger is of constant rotation speed type, and at least The temperature sensor, a relative hygrometer, and a data operation unit electrically connected so that the measurement value by the thermometer is input, the data operation unit is provided at the cooling tower installation location. The temperature at which the set temperature of the outlet temperature of this cooling tower and the upper limit value, the lower limit value of the outlet temperature, and the target value slightly higher than the set value are set at the boundary of this set value, when the wet-bulb temperature of There is a setting section, The data calculation unit is further provided with a setting unit for presetting a time table of the rotation direction of the blower according to the outlet temperature, and the data calculation unit rotates the motor of the blower based on the outlet temperature. A control unit that controls the number of rotations and controls the rotation direction thereof according to the time table set in the setting unit is electrically connected to the data calculation unit and the motor drive control circuit. A characteristic cooling tower for free cooling. 2. A closed type cooling tower comprising a closed type heat exchanger, and indirectly cooling the circulating cooling water flowing in the closed type heat exchanger by spraying water from the upper water tank from the closed type heat exchanger. In the closed type cooling tower used for free cooling, the circulating cooling water obtained by stopping the operation of the refrigerator and operating only the cooling tower when the outside air wet-bulb temperature at the installation location is below freezing is used. , A temperature sensor for detecting the inlet temperature of the circulating cooling water system and a temperature sensor for detecting the outlet temperature of the circulating cooling water system are provided, and in order to obtain the outside air wet bulb temperature at the installation location of the cooling tower, A relative hygrometer that measures the relative humidity near the outside air intake part of the cooling tower and a thermometer that measures the dry-bulb temperature are installed, and the motor of the circulation pump arranged in the spray water system is a variable speed control type. The motor of the blower installed at the exhaust port of the tower is a variable speed control type, and its rotation direction can be rotated in the forward and reverse directions, and at least the temperature sensor, the relative hygrometer, and the measured value by the thermometer are input. There is provided a data operation unit electrically connected to the data operation unit, and the data operation unit has a set value of the outlet degree of the cooling tower when the wet-bulb temperature at the cooling tower installation location is below freezing. , The upper limit value of the outlet temperature, the lower limit value, and a temperature setting unit for setting a target value slightly higher than the set value are provided with the set value as a boundary, and the data calculation unit further includes the temperature in the cooling tower. The amount of water sprayed from the upper water tank onto the closed heat exchanger is divided into several stages according to the outside air wet bulb temperature, and the lower the wet bulb temperature, the larger the amount of water and the outside air wet bulb temperature. The higher the amount of water, the smaller the amount of water that is set in stages. And a setting unit in which a time table of the rotation direction of the blower according to the outlet temperature is set in advance, and the data calculating unit controls the motor of the circulation pump based on the outside air wet-bulb temperature range. Control the number of revolutions, select the amount of water sprinkling of the corresponding segment of the water spray amount of the several stages that are set in stages, and further control the number of revolutions of the motor of the blower based on the outlet temperature and For free cooling, a control unit for controlling forward / reverse rotation according to a timetable set in the setting unit is electrically connected to the data calculation unit and each motor drive control circuit. Cooling tower. 3. The cooling tower for free cooling according to claim 1, wherein the drive motor of the blower and the motor of the cooling water circulation pump are of an inverter control system. 4. The cooling tower for free cooling according to claim 1, 2 or 3, wherein the forward rotation time of the blower in the timetable is set longer than the reverse rotation time. 5. A measuring instrument is provided for measuring, as a load current, a blowing resistance of a drive motor of a blower due to freezing, and a measurement signal and the outlet temperature when the load current is equal to or more than a blockage rate of 80% due to freezing. The OR signal of the measurement signal when it exceeds the upper limit is the stop and reverse rotation command signal of the blower, and the measurement signal when the load current is equal to or less than the blockage rate 40% due to icing and the set value of the outlet temperature The cooling tower for free cooling according to claim 1, 2, 3 or 4, wherein the blower rotation direction control circuit for returning the rotation direction of the blower to the normal rotation by the OR signal of the measurement signal in the case is provided. . 6. A drive control circuit for the motor of the circulation pump responds to the outside-air wet-bulb temperature when the outside-air wet-bulb temperature fluctuates exceeding the outside-air wet-bulb temperature at each stage. The cooling tower for free cooling according to claim 2, 3, 4, or 5, wherein the cooling tower is configured to change to a predetermined water spray amount. 7. The control unit controls the rotation speed of a motor of the blower based on the change of the outlet temperature and the rotation direction is set for each of the sections of the set water spray amount. The cooling tower for free cooling according to claim 2, 3, 4, 5, or 6, wherein forward and reverse rotation control is performed according to an existing time table. 8. The timetable is characterized in that sprayed water is sprayed on a sealed heat exchanger at a predetermined amount of sprayed water, and in this state, the outlet temperature rises due to freezing in the sealed heat exchanger,
Until the target value higher than the set value is reached, the blower provided in the cooling tower is continuously rotated in the forward direction, and thereafter, when the outlet temperature reaches the target value, the rotation of the blower is stopped for a predetermined time, After the stop, when the outlet temperature further rises and reaches the upper limit value, the rotation of the blower is started in the reverse direction, and during the reverse rotation operation of the blower, the outlet temperature sharply drops and reaches the lower limit value. After that, when it starts to rise and becomes a value slightly lower than the target value, the rotation of the blower is stopped for a predetermined time, and then when the outlet temperature reaches the upper limit value, the blower is switched to normal rotation operation, Then, after the outlet temperature sharply decreases and reaches a set value, the blower is reversely rotated in the same manner as above every time the outlet temperature reaches the target value due to freezing in the closed heat exchanger. Characterized by being as something That claims 1,3,4,5,6 or 7
Cooling tower for free cooling described. 9. The timetable divides the spray amount of the spray water from the upper water tank onto the closed heat exchanger into several stages according to the wet bulb temperature, and the lower the wet bulb temperature is, the lower the wet bulb temperature is. The amount of water is high, the higher the wet bulb temperature is, the smaller the amount of water is set in advance, and in the wet bulb temperature range within each of the single sections, it is sealed while maintaining the previously set water spray amount. The outlet temperature rises due to freezing in the mold heat exchanger, until the target value higher than the set value is reached, the blower provided in the cooling tower continues to rotate forward, and then the outlet temperature becomes the target value. When it reaches a value, the rotation of the blower is stopped for a predetermined time, and after the stop, when the outlet temperature further rises and reaches the upper limit value, the rotation of the blower is started in the reverse direction, and the rotation of the blower is reversed. During the rotation operation, the outlet temperature suddenly drops and reaches the lower limit value. After that, when it starts to rise and becomes a value slightly lower than the target value, the rotation of the blower is stopped for a predetermined time, and then when the outlet temperature reaches the upper limit value, the blower is switched to normal rotation operation. After that, the outlet temperature sharply decreases, reaches a set value, and then, every time the outlet temperature reaches the target value due to freezing in the sealed heat exchanger, the blower is reversely rotated in the same manner as described above. The present invention is characterized in that
Cooling tower for free cooling described. 10. The timetable according to claim 1, wherein the blower continues normal rotation operation when the outside air wet bulb temperature is in the range of 0 ° C. to + 1 ° C.
A cooling tower for free cooling according to 2, 3, 4, 5, 6, 7 or 8. 11. The return pipe of the spray water system is provided with a flow meter for measuring the flow rate of the spray water, and the flow meter is connected to a data calculator.
A cooling tower for free cooling according to 3, 4, 5, 6, 7, 9 or 10.