JP2001304652A - Air conditioner and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner with improved energy-saving properties and its control method that can reduce operation power, while securing sufficient cooling capacity, and hence can improve operation efficiency drastically. SOLUTION: The operation of a refrigeration cycle and that of a cooling water circulation cycle are controlled to a state for obtaining the maximum cooling capacity, when an indoor temperature is equal to or more than a specific value. The operation of the refrigeration cycle and that of the cooling water circulation cycle are controlled to a state for obtaining a required cooling capacity with a very small operation power, when the indoor temperature is less than the specific value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for high heat generation equipment which needs cooling even when the outside air temperature is low such as in winter, and a control method therefor.

[0002]

2. Description of the Related Art In general, an annual cooling type air conditioner is known as a device for cooling an indoor space in which a high heat generating device such as a computer is installed over a year. This air conditioner
A refrigeration cycle for circulating a refrigerant through a compressor, a water-cooled condenser, an expansion valve, and an indoor heat exchanger, and a cooling-water circulation pump, a cooling tower, and a cooling-water circulation cycle for circulating cooling water through the water-cooled condenser are provided. .

A high-temperature and high-pressure gas refrigerant discharged from a compressor is guided to a water-cooled condenser, and the gas refrigerant flowing into the water-cooled condenser is deprived of heat by cooling water flowing into the water-cooled condenser and liquefied. After the liquid refrigerant flowing out of the water-cooled condenser is decompressed by the expansion valve, it becomes a low-temperature and low-pressure liquid / gas mixed refrigerant, and is guided to an evaporator (indoor heat exchanger). In the evaporator, the liquid / gas refrigerant takes heat from indoor air and evaporates. This gas refrigerant is sucked into the compressor, and the same cycle is repeated thereafter.

[0004] The cooling water that has passed through the water-cooled condenser is led to a cooling tower, where the heat of the cooling water (heat taken from the gas refrigerant) is released to the atmosphere. The cooling water whose temperature has decreased due to the heat radiation is supplied again to the water-cooled condenser by the cooling water circulation pump.

[0005]

In an air conditioner in which the cooling operation is continued for a year, such as an annual cooling type air conditioner, there is a strong demand for a reduction in operating power and an improvement in operating efficiency.

[0006] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide an air conditioner with excellent energy saving and a control method thereof, which can reduce the operating power while securing a sufficient cooling capacity, thereby greatly improving the operating efficiency. It is in.

[0007]

An air conditioner according to a first aspect of the present invention includes a refrigeration cycle for circulating a refrigerant through a compressor, a water-cooled condenser, a decompressor, and an indoor heat exchanger, a cooling water circulation pump, and a cooling tower. A cooling water circulation cycle for circulating cooling water through the water-cooled condenser, an indoor temperature detecting means for detecting an indoor temperature, and a maximum cooling capacity is obtained when the detected temperature of the indoor temperature detecting means is equal to or higher than a predetermined value. First control means for controlling the operation of the refrigeration cycle and the operation of the cooling water circulation cycle in a state, and a required cooling capacity with a minimum operating power when the detected temperature of the indoor temperature detecting means is less than a predetermined value. And a second control means for controlling the operation of the refrigeration cycle and the operation of the cooling water circulation cycle in a state in which is obtained.

[0008] The air conditioner of the invention according to claim 2 is claim 1.
In the invention according to the first aspect, the indoor temperature detecting means is limited. That is, the indoor temperature detecting means detects, as the indoor temperature, the temperature of a predetermined location in the room, the temperature of the air taken in from the room, or the temperature of the air blown into the room.

An air conditioner according to a third aspect of the present invention is the air conditioner according to the first aspect.
In the invention according to the first aspect, each control means is limited. That is, when the room temperature is higher than a predetermined temperature range including a predetermined set value, the first control means controls the operation of the refrigeration cycle and the operation of the cooling water circulation cycle so that the maximum cooling capacity is obtained. When the room temperature is within the predetermined temperature range, the second control means controls the operation of the refrigeration cycle and the operation of the cooling water circulation cycle so that the required cooling capacity can be obtained with as little operating power as possible.

An air conditioner according to a fourth aspect of the present invention is the air conditioner according to the first aspect.
In the invention according to any one of claims 3 to 5, each control means is limited. That is, each control means
The control targets are the number of rotations of the compressor, the condensation pressure of the refrigerant in the water-cooled condenser, the amount of water sent by the cooling water circulation pump, and the amount of cooling of the cooling tower.

According to a fifth aspect of the invention, there is provided a method for controlling an air conditioner, comprising: a refrigeration cycle for circulating a refrigerant through a compressor, a water-cooled condenser, a decompressor, and an indoor heat exchanger; a cooling water circulation pump; In an air conditioner having a cooling water circulation cycle for circulating cooling water through a water-cooled condenser, the operation of the refrigeration cycle and the operation of the cooling water circulation cycle are performed so that the maximum cooling capacity is obtained when the room temperature is equal to or higher than a predetermined value. When the room temperature is less than a predetermined value, the operation of the refrigeration cycle and the operation of the cooling water circulation cycle are controlled so that the required cooling capacity can be obtained with the operation power as small as possible.

[0012]

[1] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a heat exchanger 3 a of a water-cooled condenser 3 is connected to a refrigerant discharge port of the compressor 1 via a gas-side refrigerant pipe 2. An indoor heat exchanger (evaporator) 7 is connected to the heat exchanger 3a via a condensing pressure control valve 4, a liquid-side refrigerant pipe 5, and a decompressor, for example, an expansion valve 6 with a variable opening. The refrigerant suction port of the compressor 1 is connected to 7. That is, a refrigeration cycle is formed in which the refrigerant is circulated through the compressor 1, the water-cooled condenser 3, the condensation pressure control valve 4, the liquid-side refrigerant pipe 5, the expansion valve 6, and the indoor heat exchanger 7.

The condensing pressure control valve 4 is a so-called three-way valve, and a bypass pipe 2a is provided between the condensing pressure control valve 4 and the refrigerant inflow side of the heat exchanger 3a. The condensing pressure control valve 4 relatively increases or decreases the amount of the refrigerant passing through the heat exchanger 3a and the amount of the refrigerant passing through the bypass pipe 2a by changing the opening degree, whereby the condensing pressure of the refrigerant in the heat exchanger 3a is increased. Adjust

An indoor blower 8 is provided near the indoor heat exchanger 7. The indoor blower 8 has a function of sucking indoor air, passing it through the indoor heat exchanger 7, and blowing out the air (cool air) passing through the indoor heat exchanger 7 into the room.

On the other hand, a heat exchanger 14 of a cooling tower 13 is connected to a water discharge port of the cooling water circulation pump 11 via a water pipe 12. The cooling tower 13 includes, in addition to the heat exchanger 14, a sprinkler 15 that applies cooling water to the heat exchanger 14, and a sprinkler pump 1 that supplies cooling water accumulated in the bottom of the tower to the sprinkler 15.
6. A cooling tower blower 17 for introducing outside air to cool the cooling water is provided.

A water pipe 18 is connected to the heat exchanger 14 of the cooling tower 13.
Is connected to the heat exchanger 3b of the water-cooled condenser 3 through
The water inlet of the cooling water circulation pump 11 is connected to the heat exchanger 3b. That is, a cooling water circulation cycle for circulating the cooling water through the cooling water circulation pump 11, the cooling tower 13, and the water-cooled condenser 3 is configured.

The compressor 1 has a motor whose rotation speed is variable. The compressor drive unit 2 is used to drive the compressor 1.
1 is provided. The compressor drive unit 21 has a function of outputting a drive voltage for the motor of the compressor 1 and changing the frequency of the drive voltage. Due to this frequency change, the rotation speed of the motor of the compressor 1 changes, and accordingly, the capacity (also called capacity) of the compressor 1 changes.

A blower driving unit 22 is connected to the indoor blower 8. The blower drive unit 22 has a function of outputting a drive voltage for the motor of the indoor blower 8 and changing the frequency of the drive voltage. Due to this frequency change, the amount of air blown by the indoor blower 8 changes.

A pump driving unit 23 is connected to the cooling water circulation pump 11. The pump drive unit 23 has a function of outputting a drive voltage to the motor of the cooling water circulation pump 11 and changing a frequency of the drive voltage. Due to this frequency change, the water supply amount of the cooling water circulation pump 11 changes.

An indoor temperature sensor (indoor temperature detecting means) 3 for detecting the temperature Tr of the indoor air at a predetermined location in the room to be air-conditioned.
1 is provided. An intake air temperature sensor (indoor temperature detection means) 32 for detecting the intake air temperature Ti is provided in the intake air passage of the indoor air based on the operation of the indoor blower 8. A blow-out temperature sensor (indoor temperature detecting means) 33 for detecting the temperature To of the blow-out air in a blow-out air path for air-conditioning air (cool air) based on the operation of the indoor blower 8.
Is provided.

Outside the room where the cooling tower 13 is installed, an outside air temperature sensor (outside air temperature detecting means) 34 for detecting an outside air temperature Tx is provided.

A control unit 40 controls the entire air conditioner. The control unit 40 includes the condensing pressure control valve 4, the expansion valve 6, the water spray pump 16, the cooling tower blower 17, the compressor drive unit 21, the blower drive unit 22, the pump drive unit 23, the indoor temperature sensor 31, and the suction temperature sensor. 32, blowout temperature sensor 33, outside air temperature sensor 34, and operation unit 41
Is connected.

The control unit 40 has the following means (1) and (2) as main functions. (1) The indoor temperature (any of the detected temperatures of the indoor temperature sensors 31, 32, and 33) is equal to or more than a predetermined temperature range [(Ts−α) including a set value Ts predetermined by the operation unit 41, and (Ts +
β) or less], control means for controlling the operation of the refrigeration cycle and the operation of the cooling water circulation cycle so that the maximum cooling capacity is obtained.

(2) When the room temperature is within the predetermined temperature range [(Ts
-Α) or more and (Ts + β) or less], a state in which the required cooling capacity can be obtained with the smallest possible operating power, that is, the operating efficiency {= cooling capacity (kW) / operating power (kW)}. Control means for controlling the operation of the refrigeration cycle and the operation of the cooling water circulation cycle to a maximum state.

Next, the operation of the above configuration will be described with reference to FIGS. When a start operation of the operation is performed by the operation unit 41 (YES in step 101), any one of the detected temperature Tr of the indoor temperature sensor 31, the detected temperature Ti of the suction temperature sensor 32, and the detected temperature To of the outlet temperature sensor 33 is selected. One of them is taken as the room temperature (step 102).

The room temperature is equal to or higher than a predetermined temperature range [(Ts-α) including a set value Ts predetermined by the operation unit 41,
(Ts + β) or less], it is determined that there is a thermo-on request (YES in step 103),
A cooling operation is performed (step 104).

That is, the compressor 1 includes a compressor driving unit 21
, And discharges a high-temperature and high-pressure gas refrigerant.
This gas refrigerant is supplied to the water-cooled condenser 3 by the gas side refrigerant pipe 2.
, And exchanges heat with the cooling water passing through the heat exchanger 3b to condense to become a liquid refrigerant. This liquid refrigerant is guided to the expansion valve 6 by the liquid-side refrigerant pipe 5, where the pressure is reduced.
It becomes a low-temperature, low-pressure liquid-gas mixed refrigerant. Further, the liquid-gas mixed refrigerant is guided to the indoor heat exchanger (evaporator) 7, evaporates by exchanging heat with the indoor air sucked by the operation of the indoor blower 8, evaporates to a low-pressure gas, and becomes a compressor again. Inhaled into 1. The air that has passed through the indoor heat exchanger 7 is blown into the room as cooling air.

The cooling water passing through the heat exchanger 3b of the water-cooled condenser 3 is guided to a cooling tower 13 by a cooling water circulation pump 11,
After heat exchange with the outside air, it reaches the water-cooled condenser 3 again.

During the cooling operation, if the room temperature is higher than the predetermined temperature range, it is determined that the current cooling capacity does not satisfy the required cooling capacity (NO in step 105).
The operation in the maximum capacity control mode is executed (step 10).
6). In the maximum capacity control mode, the rotation speed of the compressor 1 (the output frequency of the compressor drive unit 21), the water supply amount of the cooling water circulation pump 11 (the output of the pump drive unit 23) are set so that the maximum cooling capacity that can be exhibited is obtained. Frequency) and cooling tower 13
(The operation / stop of the watering pump 16 and the air volume of the cooling tower blower 17) are controlled. That is, the cooling tower blower 17 of the cooling tower 13 is operated at the maximum air volume, the cooling volume of the cooling tower 13 is maximized, and the cooling water circulation pump 1
The heat transfer effect in the water-cooled condenser 3 is promoted by increasing the amount of water supply by operating 1 at the maximum rotation speed. In accordance with this, while the rotation speed of the compressor 1 is increased,
The air volume of the indoor blower 8 is increased, and the opening of the expansion valve 6 is controlled. In this manner, by performing the operation in the maximum capacity control mode, the room temperature quickly changes toward the set value Ts.

If the room temperature is within the predetermined temperature range, the set value is determined by judging that the current cooling capacity satisfies the required cooling capacity (YES in step 105) or by a small increase or decrease in the cooling capacity. The operation in the maximum COP control mode is executed based on the determination that the environment of Ts can be maintained (step 107). In the maximum COP control mode, a state in which a required cooling capacity is obtained with as small an operation power (power consumption) as possible, that is, an operation efficiency {= cooling capacity (k
W) / operating power (kW)}, the rotation speed of the compressor 1 (output frequency of the compressor drive unit 21), the opening degree of the condensing pressure control valve 4 (condensation of refrigerant in the water-cooled condenser 3) Pressure), the amount of water supplied by the cooling water circulation pump 11 (pump driving unit 2)
3), and the amount of cooling of the cooling tower 13 (the operation / stop of the watering pump 16 and the amount of air of the cooling tower blower 17) are controlled.

The operation in the maximum COP control mode includes, for example, the following method. The water sprinkling pump 16 of the cooling tower 13 is turned on, the cooling tower blower 17 is operated at the rated power, and the number of rotations of the cooling water circulating pump 11 is increased to increase the amount of water supply, thereby condensing the refrigerant in the water-cooled condenser 3. The pressure can be reduced. When the condensing pressure of the refrigerant decreases, the load on the compressor 1 decreases, and power consumption in the compressor 1 can be suppressed while maintaining the required cooling capacity. That is, this is a control for maintaining the required cooling capacity while operating the equipment of the refrigeration cycle at a low load, and instead operating the equipment of the cooling water circulation cycle at a high load.

As described above, the compressor 1 which is a component of the refrigeration cycle is operated at a low load, and the cooling water circulating pump 11, the water sprinkling pump 16 and the cooling tower blower 17 which are the components of the cooling water circulating cycle are instead operated at a high load. A first operation power determination condition is defined for control for maintaining a required cooling capacity while operating with a load. The first operating power determination condition is for determining the individual operating power (power consumption) of each device using the current room temperature and the outside air temperature as parameters, and is stored in the memory of the control unit 41.

On the other hand, the operation of both or one of the water spray pump 16 and the cooling tower blower 17 of the cooling tower 13 is stopped.
Alternatively, when the operation is performed at the rated power or less, the cooling tower 13
Of the cooling water passing through the water-cooled condenser 3 increases. In this case, the condensing pressure of the refrigerant in the water-cooled condenser 3 is increased. However, if there is a margin in the operating state (the number of revolutions) of the compressor 1, the number of revolutions of the compressor 1 is increased.
If the compression ratio is increased, the required cooling capacity can be maintained. That is, this is a control for maintaining the required cooling capacity while operating the equipment of the cooling water circulation cycle at a low load, and instead operating the equipment of the refrigeration cycle at a high load.

As described above, the cooling water circulation pump 11, the water sprinkling pump 16, and the cooling tower blower 17 which are components of the cooling water circulation cycle are operated at a low load, and the compressor 1 which is a component of the refrigeration cycle is instead operated at a high load. A second operating power determination condition is defined for control for maintaining required cooling capacity while operating with a load. The second operating power determination condition is also for determining the individual operating power of each device using the current room temperature and the outside air temperature as parameters, and is stored in the memory of the control unit 41.

It is to be noted that a part of the cooling water circulation cycle is operated at a low load, and instead, the remaining equipment of the cooling water circulation cycle and the equipment of the refrigeration cycle are operated at a high load while maintaining the required cooling capacity. Some controls do. For example, the cooling tower blower 17 of the cooling water circulation cycle is operated at a low load, and the cooling water circulation pump 11, the sprinkling pump 16 and the compressor 1 of the refrigeration cycle of the cooling water circulation cycle are operated at a high load. This is control for maintaining the cooling capacity. For this control, a third operating power determination condition is defined.

While operating some equipment of the cooling water circulation cycle and equipment of the refrigeration cycle at low load, and instead operating the remaining equipment of the cooling water circulation cycle at low load,
Some controls maintain the required cooling capacity. For example, the cooling tower blower 17 of the cooling water circulation cycle and the compressor 1 of the refrigeration cycle are operated at a low load, and the cooling water circulation pump 11 and the water sprinkling pump 16 of the cooling water circulation cycle are operated at a high load. This is a control that maintains the ability. For this control, a fourth operating power determination condition is defined.

The third and fourth operating power determination conditions are also used to determine the individual operating power of each device using the current indoor temperature and outside air temperature as parameters, and are stored in the memory of the control unit 41. ing.

In addition, a plurality of types of control for maintaining a required cooling load while operating an arbitrary device at a low load and operating another device at a high load instead are provided. The fifth, sixth,... Operating power determination conditions are determined for each of these controls, and these operating power determination conditions are stored in the memory of the control unit 41.

During operation, the indoor temperature (the indoor temperature sensor 31,
32, 33) and the outside air temperature Tx
Based on the (temperature detected by the outside air temperature sensor 34), the first operating power determination condition in the memory of the control unit 41 is referred to,
The operating power to be determined for each device is determined, and the total value of the operating power is determined. Similarly, referring to all the remaining operating power determination conditions, the operating power to be determined for each device is determined, and the total value of the operating power is determined. Then, the obtained total values are compared with each other.

For example, if the sum of the operating powers determined by referring to the first operating power determination condition is the smallest, the operating power determined by referring to the first operating power determining condition is determined. The operation of each device is controlled so that If the total value of the operating power obtained by referring to the second operating power determining condition is the smallest, the operation of each device is controlled so that the operating power becomes the operating power obtained by referring to the second operating power determining condition. You.

In this way, it is possible to execute the operation in which the operation efficiency is maximized.

In the operation in the maximum COP control mode,
On the high temperature side of the predetermined temperature range, an operation of slightly increasing the rotation speed of the compressor 1 in the increasing direction is performed, an operation of maintaining the rotation speed of the compressor 1 at or near the set value Ts is performed, and the compression is performed on the low temperature side. An operation for slightly reducing the rotation speed of the machine 1 in the decreasing direction is executed.

When the room temperature becomes lower than the predetermined temperature range, it is determined that there is a thermo-off request (step 10).
No. 3), the cooling operation is interrupted (step 10).
8).

When the operation stop operation is performed by the operation unit 41 (YES in step 109), the cooling operation is stopped (step 110).

As described above, the operation of the refrigeration cycle and the operation of the cooling water circulation cycle are controlled so that the maximum cooling capacity is obtained when the room temperature is equal to or higher than the predetermined value. By controlling the operation of the refrigeration cycle and the operation of the cooling water circulation cycle so that the efficiency is maximized, the operating power can be reduced while securing sufficient cooling capacity, and the operating efficiency can be significantly improved. . Therefore, the air conditioner is excellent in energy saving.

In the operation of the refrigeration cycle merely for securing the cooling capacity and the operation of the cooling water circulation cycle, the operation power may be excessively consumed.
By controlling the operation of the refrigeration cycle and the operation of the cooling water circulation cycle so that the operation efficiency is maximized, it is possible to minimize the consumption of operation power while ensuring sufficient cooling capacity.

[2] The second embodiment will be described.
The control unit 40 has the following means (1) and (2) as main functions. (1) The number of revolutions of the compressor 1 (the output frequency of the compressor drive unit 21) is controlled according to the difference between the indoor temperature (any of the detected temperatures of the indoor temperature sensors 31, 32, and 33) and the set value Ts. Control means.

(2) The state where the required cooling capacity is obtained with the smallest possible operating power (power consumption), that is, the state where the operating efficiency {= cooling capacity (kW) / operating power (kW)} is maximized. Control means for controlling the operation of the refrigeration cycle and the operation of the cooling water circulation cycle. Other configurations are the same as those of the first embodiment, and a description thereof will be omitted.

Next, the operation of the above configuration will be described. During the cooling operation, the detected indoor temperature (the indoor temperature sensors 31 and 3)
The rotation speed of the compressor 1 (the output frequency of the compressor drive unit 21) is controlled according to the difference between the set temperature Ts and the detected temperature Ts. At this time, if a temperature exceeding a certain difference β with respect to the set value Ts is detected, that is, if the detected temperature> Ts + β, the control unit 40 determines that the room needs to be cooled immediately, Operation in the maximum capacity control mode is executed.

The specific control of the operation in the maximum capacity control mode is the same as that of the first embodiment, and the description thereof will be omitted.

Next, when a temperature having a certain width with respect to the set value Ts is detected, that is, when Ts + β ≧ detected temperature ≧ Ts−α, the control unit 40 determines that the air conditioner has a predetermined capacity. It is determined that the vehicle is almost satisfied, and the operation in the maximum COP control mode is executed.

Since the specific control of the operation in the maximum COP control mode is the same as that of the first embodiment, the description is omitted.

When the operation in the maximum COP control mode is executed, if the room temperature is higher than the set value Ts, that is, if Ts + β ≧ detection temperature ≧ Ts, the rotation speed of the compressor 1 is reduced. When the room temperature is lower than the set value Ts, that is, when the room temperature is lower than the set value Ts,
If Ts ≧ detected temperature ≧ Ts−α, an operation of slightly increasing the rotation speed of the compressor 1 is also performed.

By performing the above-described control, the operating power can be reduced while securing a sufficient cooling capacity corresponding to the air-conditioning load, and the operating efficiency can be greatly improved. Therefore, the air conditioner is excellent in energy saving.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention.

[0056]

As described above, according to the present invention, it is possible to reduce the operating power while securing a sufficient cooling capacity, thereby achieving a great improvement in the operating efficiency and excellent energy saving. An air conditioner and a control method thereof can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of each embodiment.

FIG. 2 is a flowchart for explaining the operation of the first embodiment.

FIG. 3 is a diagram showing a relationship between a room temperature change and operation control in the first embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Gas side refrigerant piping, 3 ... Water-cooled condenser, 3
a, 3b: heat exchanger, 4: condensation pressure control valve, 5: liquid side refrigerant pipe, 6: expansion valve, 7: indoor heat exchanger (evaporator), 8
... indoor blower, 11 ... cooling water circulation pump, 12 ... water pipe,
13: cooling tower, 14: heat exchanger, 15: water sprinkler, 16 ...
Watering pump, 17: cooling tower blower, 18: water pipe, 21 ...
Compressor drive unit, 22 ... Blower drive unit, 23 ... Pump drive unit, 31 ... Indoor temperature sensor (indoor temperature detection means), 32
... Suction temperature sensor (indoor temperature detecting means), 33 ... Blow-out temperature sensor (indoor temperature detecting means), 34 ... Outside air temperature sensor (outside air temperature detecting means), 40 ... Control unit, 41 ...
Operation unit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigenori Waratani 3-4-1, Shibaura, Minato-ku, Tokyo Inside NTT Facilities Inc. (72) Minoru Okada 3-chome Toyosu, Koto-ku, Tokyo No. 3 Inside NTT Data Corporation (72) Inventor Takahiro Ezaki 3-3-Toyosu Toyosu, Koto-ku, Tokyo 3 72 Inside NTT Data Corporation (72) Inventor Toshihiro Nambu Tokyo 3-3-3 Toyosu, Koto-ku, Tokyo F-term in NTT Data Corporation (reference) 3L060 AA03 CC02 DD02 EE02

Claims (5)

[Claims] 1. A refrigeration cycle for circulating a refrigerant through a compressor, a water-cooled condenser, a decompressor, and an indoor heat exchanger, a cooling-water circulation pump, a cooling tower, and a cooling-water circulation cycle for circulating cooling water through the water-cooled condenser. An indoor temperature detecting means for detecting an indoor temperature; and when the detected temperature of the indoor temperature detecting means is equal to or higher than a predetermined value,
In a state where the maximum cooling capacity is obtained, first control means for controlling the operation of the refrigeration cycle and the operation of the cooling water circulation cycle, and when the detected temperature of the indoor temperature detection means is less than a predetermined value,
An air conditioner comprising: a second control unit configured to control the operation of the refrigeration cycle and the operation of the cooling water circulation cycle in a state where a required cooling capacity can be obtained with a minimum operating power. 2. The air conditioner according to claim 1, wherein the indoor temperature detecting means detects, as the indoor temperature, a temperature at a predetermined place in the indoor room, a temperature of air taken in from the indoor room, or a temperature of air blown into the indoor room. An air conditioner characterized by detecting. 3. The air conditioner according to claim 1, wherein the first control unit is configured to refrigerate the air conditioner so that the maximum cooling capacity is obtained when the room temperature is higher than a predetermined temperature range including a predetermined set value. The second control means controls the operation of the cooling cycle and the operation of the cooling water circulation cycle. When the room temperature is within the predetermined temperature range, the second control means sets the refrigeration cycle to a state where the required cooling capacity can be obtained with the minimum operating power. Controlling the operation of the cooling water circulation cycle and the operation of the air conditioner. 4. The air conditioner according to claim 1, wherein each of the control means controls a rotation speed of the compressor,
An air conditioner comprising: a condensing pressure of a refrigerant in the water-cooled condenser, a flow rate of the cooling water circulation pump, and a cooling rate of the cooling tower. 5. A refrigeration cycle for circulating refrigerant through a compressor, a water-cooled condenser, a decompressor, and an indoor heat exchanger;
A cooling water circulation pump, a cooling tower, and a cooling water circulation cycle that circulates cooling water through the water-cooled condenser, wherein the room temperature is equal to or higher than a predetermined value, and a maximum cooling capacity is obtained. Controlling the operation and the operation of the cooling water circulation cycle, the operation of the refrigeration cycle and the operation of the cooling water circulation cycle in a state in which the required cooling capacity is obtained with a minimum operating power when the room temperature is less than a predetermined value. A method for controlling an air conditioner, characterized by controlling.