JP4829147B2 - Air conditioning equipment - Google Patents

Description

The present invention relates to an air conditioner, and more particularly to a technique for prolonging a period (free cooling) in which cooling water for cooling the air conditioner is manufactured only by a cooling tower without using a refrigerator.
As is well known, semiconductor manufacturing factories and computer rooms cool throughout the year. Chilled water for cooling these is basically produced by a refrigerator, but in order to save energy when the outside air wet bulb temperature is low during the intermediate period and winter, some cooling of the precooled water is possible in the cooling tower. (Hereinafter referred to as free cooling), the precooled water is used for precooling. However, if free cooling is used as an alternative to a refrigerator, the operation period is very short to ensure a water temperature of 7 ° C, energy savings cannot be achieved, and only the initial cost increases (the ambient wet bulb temperature must be 3 ° C or less) ). Therefore, a pre-cooling coil and a cold water coil are arranged in the front and rear stages in the air conditioner, and the pre-cooling coil in the front stage is pre-cooled to a temperature of 18 ° C. or less with cooling water having a temperature of 18 ° C. or less determined in accordance with the conveyance power and the chiller reduction power. The air is precooled with precooled water, and further cooled with chilled water from a refrigerator with a chilled water coil at the subsequent stage as a free cooling operation (see, for example, Patent Documents 1 to 5).

A conventional air-conditioning facility that performs a free cooling operation will be described with reference to FIGS.
In the air conditioning equipment, a precooling coil 102 is provided in the air conditioner 101, and precooling water flowing through the precooling coil 102 is conveyed by a circulation pump (P 4) 103 through a precooling water circulation path 130 and cooled by a heat exchanger 104. A cooling tower (CT3) 105 for free cooling and its circulation pump (P3) 106 are provided to flow the cooling water to the primary side of the heat exchanger 104 via the cooling water circulation path 131 for free cooling. Cooling by outside air. A chilled water coil 107 is installed after the precooling coil 102, and chilled water flowing through the chilled water coil 107 is supplied to the first refrigerator (R 1) 108 and the second refrigerator (R 2) 109 via the chilled water circulation path 132. And is conveyed by the pump (CP1) 110 and the pump (CP2) 111 via the forward header 112 and the return header 113. The first refrigerator (R1) 108 is connected to a cooling tower (CT1) 114 for the first refrigerator and a circulation pump (P1) 116 via a cooling water circulation path 133. The second refrigerator (R2) 109 is connected to a cooling tower (CT2) 115 for the second refrigerator and a circulation pump (P2) 117 via a cooling water circulation path 134. Moreover, the air conditioner 101 is installed in the air conditioning flow path of the computer room 118, for example.

Next, with this air conditioning equipment, for example, the room temperature of the computer room 120 in which the computer 119 is installed is 26 ° C., the temperature of the air blown into the underfloor space 121 is 20 ° C., and the temperature of the air returning to the ceiling space 122 is 27 ° C. A case where the temperature environment is maintained will be described.
The chilled water coil 107 at the rear stage of the air conditioner 101 is fed with cold water of 7 ° C. from the forward header 112 by the pump (CP1) 110 via the forward path 132a of the cold water circulation path 132 and returns to the air conditioner 101 27 The air is cooled to 20 ° C. by exchanging heat with the indoor return air at 0 ° C. The air at 20 ° C. is conveyed by the air conditioner 101 from the underfloor space 121 of the computer room 118 to the computer room 120 where the computer 119 is installed, and the air conditioner room where the air conditioner 101 is installed via the ceiling space 122. Return to 123. The chilled water heat-exchanged by the chilled water coil 107 at the subsequent stage is heated to 14 ° C. and returned to the return header 113 via the return path 132 b of the chilled water circulation path 132. When free cooling is performed, a cooling tower (CT3) 105, a circulation pump (P3) 106, and a circulation pump (P4) 103 for free cooling are provided so that cooling water at 20 ° C. can be conveyed to the precooling coil 102. Operate and carry 18 ° C. cooling water to heat exchanger 104.

  Further, the outdoor air wet bulb temperature T1 measured by the outdoor air wet bulb thermometer is input to the controller 124 via the temperature controller TIC1. The water temperature T6 in the cooling tower (CT3) 105 for free cooling is measured by a water temperature gauge and input to the controller 124 via the temperature controller TIC6. The controller 124 controls the operation of the cooling tower (CT3) 105 for free cooling, the fan of the cooling tower (CT2) 115 for the second refrigerator, and the circulation pump (P4) 103. The temperature T2 of the return path 130b of the precooling water circulation path 130 to the heat exchanger 104 of the precooling water is measured by a water thermometer and input to the controller 124 via the temperature controller TIC2. If the temperature T2 of the return path 130b to the heat exchanger 104 of the precooling water falls below the lower limit value of the set temperature, the power supply frequency of the circulation pump (P4) 103 is lowered to reduce the rotational speed and reduce the flow rate.

In addition, a valve (VE2) 126 is provided on the outgoing path 130a of the precooling water circulation path 130 to the precooling coil 102 of the precooling water. The valve (VE2) 126 is proportionally controlled by the temperature controller TIC7. The temperature controller TIC7 controls the opening degree of the valve (VE2) 126 based on the precooled water outlet air temperature T7 in the air conditioner 101 based on the measured value from the thermometer.
A valve (VE1) 125 is provided on the outgoing path 132a of the chilled water circulation path 132 conveyed from the first refrigerator (R1) 108 and the second refrigerator (R2) 109 to the cooling coil 107 of the air conditioner 101. is there. The valve (VE1) 125 is proportionally controlled by the temperature controller TIC5. The temperature controller TIC5 controls the opening degree of the valve (VE1) 125 based on the blowing temperature T5 measured by the thermometer arranged in the underfloor space 121.

  In the cold water circulation path 132 of the chilled water conveyed from the first refrigerator (R1) 108 and the second refrigerator (R2) 109 to the cooling coil 107 of the air conditioner 101, one water temperature gauge is returned to the outgoing path 132a. A flow meter F3 and a water temperature meter are provided in the path 132b. The measured value T3 of the water thermometer on the outgoing path 132a is input to the calorific value calculation controller 127 via the TIC3. The measured value of the flow meter F3 on the return path 132b is input to the calorific value calculation controller 127 via the flow rate controller FIC3. The measured value T4 of the thermometer on the return path 132b is input to the calorific value calculation controller 127 via the TIC4. The calorific value calculation controller 127 includes a first refrigerator (R1) 108, a second refrigerator (R2) 109, a cooling tower (CT1) 114 for the first refrigerator, and a cooling tower ( CT2) The operation of the fan 115, the pump (CP1) 110, and the pump (CP2) 111 is controlled.

Next, based on FIG. 17, operation | movement of an air conditioning installation is demonstrated.
First, the air conditioner 101 is operated, the first refrigerator (R1) 108, the cooling tower (CT1) 114 fan for the first refrigerator, the cooling tower circulation pump (P1) 116, and the circulation pump (CT1). 110 is operated (steps S100 and S101).
Next, the temperature T5 of the air blown from the air conditioner 101 is measured with the thermometer in the underfloor space 121 of the computer room 118, and the valve (VE1) 125 is proportionally adjusted so that the temperature controller TIC5 becomes the set blowing temperature. Control (step S102).

  Next, the heat quantity q = Q (T3−T4) (kcal / h) is obtained from the water temperature T3 of the outgoing path 132a of the cold water circulation path 132, the water temperature T4 of the return path 132b, and the flow rate Q measured by the flowmeter F3. Then, the calorific value calculation controller 127 determines whether or not the obtained calorie q is equal to or greater than the set calorie (step S103). If it is less than the set heat amount, the process returns to step S101, and if it is determined that the heat quantity is equal to or greater than the set heat amount, the process proceeds to step S104.

Next, the outside air wet bulb temperature T1 measured by the outside air wet bulb thermometer is input to the controller 124 via the temperature controller TIC1. The controller 124 determines whether or not the outdoor wet bulb temperature T1 is less than 5 ° C. (step S104). If the outdoor wet bulb temperature T1 is 5 ° C. or higher, the process proceeds to step S113, and if the outdoor wet bulb temperature T1 is less than 5 ° C., the process proceeds to step S105.
Next, when the outside air wet bulb temperature T1 is 5 ° C. or less, the fan of the cooling tower (CT3) 105 for free cooling is operated, and the circulation pump (P3) 106 and the circulation pump (P4) 103 are operated. (Step S105).

Next, the temperature controller TIC7 proportionally controls the valve (VE2) 126 so that the outlet air temperature T7 from the precooling coil 102 of the air conditioner 101 becomes the preset precooled water outlet air temperature (step S106).
Next, it is determined whether or not the cooling water temperature T6 of the cooling tower (CT3) 105 for free cooling is lower than 5 ° C. (step S107). When the cooling water temperature T6 is less than 5 ° C., the fan of the cooling tower (CT3) 105 for free cooling is stopped (step S108). When the cooling water temperature T6 is 5 ° C. or higher, the process returns to step S104.

Next, it is determined whether or not the cooling water temperature T6 of the cooling tower (CT3) 105 for free cooling is 5 ° C. or higher (step S109). When the cooling water temperature T6 is less than 5 ° C., the process returns to step S108.
Next, it is determined whether or not the outdoor wet bulb temperature T1 is 5 ° C. + 0.5 ° C. or higher (step S110). If the outdoor wet bulb temperature T1 is less than 5 ° C. + 0.5 ° C., the process returns to step S105.

Next, the fan of the cooling tower (CT3) 105 for free cooling, the circulation pump (P3) 106, and the circulation pump (P4) 103 are stopped (step S111).
Next, it is determined whether to stop the air conditioner 101 (step S112). In the case of stopping, the process proceeds to step S117. If not stopped, as in the negative of step S104, the second refrigerator (R2) 109, the fan of the cooling tower (CT2) 115 for the second refrigerator, the circulation pump (P2) 117, the circulation pump (CP2 ) 111 is operated (step S113).

Next, it is determined whether the heat quantity q is equal to or less than a set value (step S114). If the amount of heat is greater than or equal to the set value, the process returns to step S104.
Next, when the amount of heat is equal to or less than the set value, the second refrigerator (R2) 109, the fan of the cooling tower (CT2) 115 for the second refrigerator, the circulation pump (P2) 117, the circulation pump (CP2) ) 111 is stopped (step S115).

Next, it is determined whether or not to stop the air conditioner 101 (step S116). In the case of stopping, the process proceeds to step S117. When not stopping, it returns to step S103.
Next, the air conditioner 101 is stopped, and the first refrigerator (R1) 108, the fan of the cooling tower (CT1) 114 for the first refrigerator, the circulation pump (P1) 116, and the circulation pump (CP1) 110 are turned on. Stop (steps S117 and 118).

  Based on FIG. 18, the operation in the summer and intermediate periods will be described. Here, the outdoor wet bulb temperature was 13 ° C or higher in summer (4360 hours per year for Tokyo weather data), and the outdoor wet bulb temperature was 5 ° C or higher and less than 13 ° C (2100 hours per year for Tokyo meteorological data) in the intermediate period. . Here, since free cooling is not performed by the free cooling cooling tower (CT3) 105, the free cooling cooling tower (CT3) 105, the circulation pump (P3) 106, the heat exchanger 104, the circulation pump (P4) ) 103, the pre-cooling coil 102 is omitted.

  In this season, the cooling in the cooling tower (CT3) 105 for free cooling becomes the outside wet bulb temperature T1 that cannot be cooled below the set water temperature of 18 ° C., so the process proceeds to step S113 and the cooling tower for free cooling ( CT3) 105 and circulation pump (P3) 106 are stopped, and circulation pump (P4) 103 is also stopped. Since the indoor heat load increases in summer and the like, the cooling of the pre-cooled portion is further eliminated by the chilled water coil 107 at the rear stage of the air conditioner 101 for this cooling. Therefore, the first refrigerator (R1) 108, which has been operated so far, the pump In addition to (CP1) 110, the second refrigerator (R2) 109 and the pump (CP2) 111 are operated to increase the amount of water in the subsequent cooling coil 107.

The winter operation will be described with reference to FIG. Here, the outdoor wet bulb temperature was less than 5 ° C. in winter (2300 hours per year in Tokyo weather data).
In this season, since the set temperature of the cooling water is the outside air wet bulb temperature T1 of 18 ° C. or less, the process proceeds to step 105, the cooling tower (CT3) 105 for free cooling, the circulation pump (P3) 106, and the circulation pump (P4). 103 is driven. The cooling water in the outgoing path 132a of the cold water circulation path 132 is heated by exchanging heat with the indoor circulation air in the pre-cooling coil 102 of the air conditioner 101, and conveyed to the heat exchanger 104 via the return path 132b of the cold water circulation path 132. Heat exchange with the cooling water in the outgoing path 131a of the cooling water circulation path 131 for free cooling is performed. This cooling water is conveyed to the cooling tower (CT3) 105 for free cooling by the circulation pump (P3) 106 via the return path 131b of the cooling water circulation path 131 for free cooling. The conveyed cooling water is cooled to a cooling water set water temperature of 18 ° C. or lower by a cooling tower (CT 3) 105 for free cooling, and is again conveyed to the heat exchanger 104. At this time, in the chilled water coil 107 at the latter stage, the building load is eliminated in the winter, and the outside air cooling load is eliminated. Therefore, the indoor load is small, and the cooling of the first refrigerator (R1) 108 can be used. A part of the cold water to be conveyed is introduced, and the air is cooled to the set room temperature.
Japanese Patent No. 2997661 JP 2002-61911 A JP-A-4-208332 JP 2005-214608 A JP 2002-115863 A

  However, in the conventional air-conditioning equipment, cold water of 18 ° C. or lower cannot be produced in the intermediate period when the outdoor air wet bulb temperature T1 is high. This period was longer than the operable winter time, and the free cooling facility was not operated effectively. During the period when free cooling is not possible, energy is required to cool the chilled water by operating the compression and absorption chillers. There is a problem that it is short.

Moreover, in the cooling tower having the capacity selected according to the rated capacity of the cooling tower for the centrifugal chiller, the heat load in charge of free cooling is used to cool the cooling water having a water temperature of 23 ° C. to 18 ° C. T1 is 5 ° C. or less. However, there was a problem that the free cooling time at that time was as short as 2300 hours a year in the climate of Tokyo.
Furthermore, increasing the capacity of the cooling tower increases the initial cost and is not a good idea.

In addition, during the time when free cooling is not possible, there is a problem that a large amount of power consumption energy is required because the compressor of the refrigerator is used.
The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an air-conditioning facility capable of producing cold water only with a cooling tower even at a higher outdoor wet bulb temperature than before. .

  Another object of the present invention is to provide an air-conditioning facility that can increase the annual free cooling operation time.

  The invention according to claim 1 is a first air-conditioner provided with a pre-cooling coil and a cooling coil, an outside air wet bulb thermometer, and a first operation that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer. A refrigerator, a cooling tower for the first refrigerator that is operated regardless of the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer, a liquid pump, and the first refrigerator and the first A first cooling water circuit that communicates with the cooling tower for the refrigerator, and at least one or more that starts and stops according to the outside air wet bulb temperature measured by the outside air wet bulb thermometer and the cooling requirement of the cooling coil A second cooling machine, a cooling tower for the second cooling machine that starts and stops according to the outside air wet bulb temperature measured by the outside air wet bulb thermometer and the cooling request of the cooling coil, and a liquid pump And connecting the second refrigerator and the cooling tower for the second refrigerator. A second cooling water circulation path, a liquid pump, a cooling water circulation path connecting the first refrigerator and the second refrigerator and the cooling coil of the air conditioner, and a cooling tower for free cooling A cooling water circulation path for free cooling that is provided with a liquid pump and communicates with the cooling tower for free cooling, a cooling water circulation path for the precooling coil that is provided with a liquid pump and communicates with the precooling coil of the air conditioner, and for the free cooling A cooling device provided between the cooling water circulation path and the cooling water circulation path for the precooling coil, and the cooling water circulation path provided between the second cooling water circulation path and the free cooling cooling water circulation path. Free cooling switching mechanism for connecting the tower and the cooling tower for the second refrigerator in series, and free cooling to the outside wet bulb temperature measured by the outside wet bulb thermometer A first setting value that cannot be performed and a second setting value that can perform free cooling, and a control device that performs switching control of the free cooling switching mechanism, wherein the free cooling switching mechanism includes the free cooling switching mechanism. A first flow path connecting the outgoing path of the cooling water circulation path and the return path of the second cooling water circulation path, an outgoing path of the free cooling cooling water circulation path, and an outgoing path of the second cooling water circulation path A second flow path connecting the first flow path, a branch point of the free cooling cooling water circulation path of the first flow path, and a branch path of the free cooling cooling water circulation path of the second flow path A first valve provided in the free cooling cooling water circulation path between the points, a second valve provided in the first flow path, and a third valve provided in the second flow path. And the second valve A fourth valve provided on the second refrigerator side from a branch point on the outgoing path side of the second cooling water circulation path of the second flow path, and the control device is measured by the outside air wet bulb thermometer When the outdoor wet bulb temperature becomes equal to or higher than the first set value, the first valve, the second valve, and the third valve are closed, the fourth valve is opened, and the second refrigerator and When performing control to operate the cooling tower for the second refrigerator, the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is lower than the first set value and equal to or higher than the second set value, The second refrigerator is stopped, the second valve and the third valve are opened, the first valve and the fourth valve are closed, and the free cooling cooling tower and the second refrigeration are closed. Free cooling by connecting the cooling tower for the machine in series Control is performed to cool the cooling water in the cooling water circulation path in two stages, and when the outside air wet bulb temperature measured by the outside air wet bulb thermometer becomes lower than the second set value, the cooling for the second refrigerator The tower is stopped, the first valve is opened, the second valve and the third valve are closed, the cooling water in the free cooling cooling water circulation path is controlled to be cooled in one stage, and the free cooling cooling water circulation is performed. Control which conveys cooling water to the said heat exchanger via a path | route is performed.

  The invention according to claim 2 is an air conditioner provided with a pre-cooling coil and a cooling coil, an outside air wet bulb thermometer, and a first operation that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer. A refrigerator, a cooling tower for the first refrigerator that is operated regardless of the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer, a liquid pump, and the first refrigerator and the first A first cooling water circuit that communicates with the cooling tower for the refrigerator, and at least one or more that starts and stops according to the outside air wet bulb temperature measured by the outside air wet bulb thermometer and the cooling requirement of the cooling coil A second cooling machine, a cooling tower for the second cooling machine that starts and stops according to the outside air wet bulb temperature measured by the outside air wet bulb thermometer and the cooling request of the cooling coil, and a liquid pump And connecting the second refrigerator and the cooling tower for the second refrigerator. A second cooling water circulation path, a liquid pump, a cooling water circulation path connecting the first refrigerator and the second refrigerator and the cooling coil of the air conditioner, and a cooling tower for free cooling A free cooling cooling water circulation path that provides a liquid pump and communicates the cooling tower for free cooling and the pre-cooling coil of the air conditioner, and between the second cooling water circulation path and the free cooling cooling water circulation path. A free cooling switching mechanism for connecting the cooling tower for free cooling and the cooling tower for the second refrigerator in series, and the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer, A first setting value for which free cooling cannot be performed and a second setting value for performing free cooling, and a control device for performing switching control of the free cooling switching mechanism. The free cooling switching mechanism includes a first flow path connecting the free cooling cooling water circulation path and a return path of the second cooling water circulation path, and a free cooling cooling water circulation path. And a second flow path connecting the outgoing path of the second cooling water circulation path, a branch point on the outgoing path side of the free cooling cooling water circulation path of the first flow path, and the second flow path A first valve provided in a forward path of the free cooling cooling water circulation path between a branch point on the outgoing path side of the cooling water circulation path for free cooling, a second valve provided in the first flow path, A third valve provided on the second flow path, and a fourth valve provided on the second refrigerator side from a branch point on the outgoing path side of the second cooling water circulation path of the second flow path. The control device includes the outside air wet bulb thermometer. When the measured outdoor wet bulb temperature is equal to or higher than the first set value, the first valve, the second valve, and the third valve are closed, the fourth valve is opened, and the second refrigeration is performed. The outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the first set value and greater than or equal to the second set value. Then, the second refrigerator is stopped, the second valve and the third valve are opened, the first valve and the fourth valve are closed, and the cooling tower for free cooling and the second valve are closed. The cooling tower for the freezer is connected in series to control cooling of the cooling water in the free cooling cooling water circulation path in two stages, and the outside wet bulb temperature measured by the outside wet bulb thermometer is When lower than the second set value, The cooling tower for the refrigerator is stopped, the first valve is opened, the second valve and the third valve are closed, and control is performed to cool the cooling water in the free cooling cooling water circulation path one stage, Control which conveys cooling water to the said pre-cooling coil via the cooling water circulation path for free cooling is performed, It is characterized by the above-mentioned.

  The invention according to claim 3 is an air conditioner provided with a cooling coil, an outside air wet bulb thermometer, a first refrigerator that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer, The first refrigerator and the first refrigerator are provided with a cooling tower for the first refrigerator and a liquid pump that operate regardless of the outside wet bulb temperature measured by the outside air bulb thermometer. A first cooling water circuit that communicates with the cooling tower, and an at least one second or more second that starts and stops in response to the outside air wet bulb temperature measured by the outside air wet bulb thermometer and the cooling coil cooling request A refrigerator, a cooling tower of the second refrigerator that starts and stops according to the temperature of the outdoor wet bulb measured by the outdoor wet bulb thermometer and the cooling request of the cooling coil, a liquid pump, and the second Second cooling connecting the second refrigerator and the cooling tower for the second refrigerator A circulation path, a cooling tower for free cooling, a liquid pump and a heat exchanger, a cooling water circulation path for free cooling communicating with the cooling tower for free cooling, a liquid pump, and the first refrigeration A chilled water circuit connecting the cooling coil of the air conditioner and the second refrigerator and the heat exchanger and the air conditioner, and provided between the second cooling water circuit and the free cooling cooling water circuit. A free cooling switching mechanism for connecting the cooling tower for free cooling and the cooling tower for the second refrigerator in series, and free air cooling to the outside air wet bulb temperature measured by the outside air wet bulb thermometer. A first setting value that cannot be performed and a second setting value that can perform free cooling, and a control device that performs switching control of the switching mechanism for free cooling. The switching mechanism for the cooling includes a first flow path connecting the forward path of the cooling water circulation path for free cooling and the return path of the second cooling water circulation path, the forward path of the cooling water circulation path for free cooling, and the first A second flow path connecting the outgoing path of the second cooling water circulation path, a branch point on the outgoing path side of the cooling water circulation path for free cooling of the first flow path, and the free cooling of the second flow path A first valve provided in a forward path of the cooling water circulation path for free cooling between a branch point on a forward path side of the cooling water circulation path, a second valve provided in the first flow path, and the second A third valve provided in the second flow path, and a fourth valve provided on the second refrigerator side from a branch point of the second cooling water circulation path in the second flow path. The control device is configured to measure the outside air measured by the outside air bulb thermometer. When the wet bulb temperature exceeds the first set value, the first valve, the second valve, and the third valve are closed, the fourth valve is opened, and the second refrigerator and the second valve are opened. Performing control to operate the cooling tower for the second refrigerator, and when the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the first set value and equal to or higher than the second set value, The second refrigerator is stopped, the second valve and the third valve are opened, the first valve and the fourth valve are closed, and the free cooling cooling tower and the second refrigerator are closed. The cooling tower of the free cooling is connected in series to control cooling of the cooling water in the cooling water circulation path for free cooling in two stages, and the outside air wet bulb temperature measured by the outside air wet bulb thermometer is the second setting. When lower than the value, the cooling for the second refrigerator The tower is stopped, the first valve is opened, the second valve and the third valve are closed, and the cooling water in the free cooling cooling water circulation path is controlled by one stage, and the free cooling cooling water circulation is performed. Control which conveys cooling water to the said heat exchanger via a path | route is performed.

According to a fourth aspect of the present invention, in the air-conditioning equipment according to the first or third aspect, the control device supplies a cooling water going-out temperature supplied to a heat exchanger of the free cooling cooling water circulation path as T _s , heat When the return temperature of the cooling water returning from the exchanger is T _r , the cooling tower inlet water temperature for free cooling (this is equal to the _Tr temperature) ° C. is T _w1 , and the free cooling cooling tower The cooling water outlet water temperature ° C is T _w2 , the cooling tower cooling water outlet water temperature ° C for the second refrigerator flowing through the second flow path is T _w3 , and the enthalpy kJ / kgDA of saturated air at T _w1 ° C is h _w1 , The enthalpy kJ / kgDA of saturated air at T _w2 ° C is h _w2 , the enthalpy kJ / kgDA of saturated air at T _w3 ° C is h _w3 , the proportional constant C ₁ inherent to the cooling tower for free cooling, the free cooling Cooling tower filling height Z ₁ for cooling, cooling tower water / air ratio L / G for free cooling N ₁ , proportional constant C ₂ inherent to the cooling tower for the second refrigerator, Free cooling shown below for obtaining tower characteristics that can be expressed by approximating the cooling tower filling height Z ₂ for the refrigerator and the cooling tower water / air ratio L / G for the second refrigerator as N ₂ T _w2 calculated for each air wet bulb temperature flowing through the cooling tower for free cooling, according to the logarithmic average formula for the cooling tower characteristics and the logarithmic average formula for the cooling tower characteristics for the second refrigerator, _Tw3 calculated for each air wet bulb temperature flowing through the cooling tower of the refrigerator
Logarithmic average formula of cooling tower characteristics for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
(U / N) ₁ = C ₁ Z ₁ N ₁ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Logarithmic average formula of cooling tower characteristics for the second refrigerator.

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
(U / N) ₂ = C ₂ Z ₂ N ₂ α ⁻¹ , 0.3 ≦ α ≦ 0.5
A graph in which the vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C for free cooling, and the horizontal axis represents the air wet bulb temperature ° C introduced into the free cooling cooling tower, the free cooling _Tw2 calculated for each air wet bulb temperature introduced to the cooling tower and T _w3 calculated for each air wet bulb temperature introduced to the cooling tower for the second refrigerator are respectively plotted to connect plot points. Two cooling tower outlet water temperature lines are created, and the cooling tower outlet water temperature line for the second refrigerator and the cooling tower cooling water outlet water temperature for free cooling on the vertical axis of the graph are parallel to the horizontal axis. The air wet bulb temperature ° C at the intersection with the drawn T _s temperature line is set as the first set value of the outside air wet bulb temperature, and the free cooling cooling tower outlet water temperature line and the vertical axis of the graph for the free cooling The cooling tower cooling water outlet water temperature in ° C is parallel to the horizontal axis. Characterized by the air wet-bulb temperature ℃ the intersection of the Drawn T _s isothermal line and a second set value of the outside air wet-bulb temperature.

According to a fifth aspect of the present invention, in the air conditioning equipment according to the first or third aspect, the control device sets a cooling water going temperature supplied to a heat exchanger of the free cooling cooling water circulation path to T _s , heat When the return temperature of the cooling water returning from the exchanger is T _r , the cooling tower inlet water temperature for free cooling (this is equal to the _Tr temperature) ° C. is T _w1 , and the free cooling cooling tower The cooling water outlet water temperature ° C is T _w2 , the cooling tower cooling water outlet water temperature ° C for the second refrigerator flowing through the second flow path is T _w3 , and the enthalpy kJ / kgDA of saturated air at T _w1 ° C is h _w1 , The enthalpy kJ / kgDA of saturated air at T _w2 ° C is h _w2 , the enthalpy kJ / kgDA of saturated air at T _w3 ° C is h _w3 , the proportional constant C ₁ inherent to the cooling tower for free cooling, the free cooling Cooling tower filling height Z ₁ for cooling, cooling tower water / air ratio L / G for free cooling N ₁ , proportional constant C ₂ inherent to the cooling tower for the second refrigerator, Free cooling shown below for obtaining tower characteristics that can be expressed by approximating the cooling tower filling height Z ₂ for the refrigerator and the cooling tower water / air ratio L / G for the second refrigerator as N ₂ According to Chebyshev's formula for cooling tower characteristics for each, T _w2 calculated for each air wet bulb temperature flowing through the cooling tower for free cooling and for each air wet bulb temperature flowing through the cooling tower for the second refrigerator _{Find the} calculated T _w3 ,
Chebyshev formula for cooling tower characteristics for free cooling U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.

Δh ₁ = t _W2 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 1 = C 1 Z 1 N 1 α -1, 0.3 ≦ α ≦ 0.5
Chebyshev formula for cooling tower characteristics for second refrigerator U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.

Δh ₁ = t _W3 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 2 = C 2 Z 2 N 2 α -1, 0.3 ≦ α ≦ 0.5
A graph in which the vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C for free cooling, and the horizontal axis represents the air wet bulb temperature ° C introduced into the free cooling cooling tower, the free cooling _Tw2 calculated for each air wet bulb temperature introduced to the cooling tower and T _w3 calculated for each air wet bulb temperature introduced to the cooling tower for the second refrigerator are respectively plotted to connect plot points. Two cooling tower outlet water temperature lines are created, and the cooling tower outlet water temperature line for the second refrigerator and the cooling tower cooling water outlet water temperature for free cooling on the vertical axis of the graph are parallel to the horizontal axis. The air wet bulb temperature ° C at the intersection with the drawn T _s temperature line is set as the first set value of the outside air wet bulb temperature, and the free cooling cooling tower outlet water temperature line and the vertical axis of the graph for the free cooling The cooling tower cooling water outlet water temperature in ° C is parallel to the horizontal axis. Characterized by the air wet-bulb temperature ℃ the intersection of the Drawn T _s isothermal line and a second set value of the outside air wet-bulb temperature.

According to a sixth aspect of the present invention, in the air conditioning equipment according to the second aspect, the control device returns the cooling water going temperature supplied to the precooling coil of the free cooling cooling water circuit T _{s from} the precooling coil. When the cooling water return temperature is T _r , the cooling tower inlet water temperature for free cooling (this is equal to the _Tr temperature) ° C is T _w1 , and the cooling tower outlet water temperature for free cooling is ° C. T _w2 , cooling tower cooling water outlet water temperature ° C for the second refrigerator flowing through the second flow path is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air at T _w2 ° C Enthalpy kJ / kgDA of h _w2 , enthalpy kJ / kgDA of saturated air at T _w3 ° C. h _w3 , proportional constant C ₁ inherent to the cooling tower for free cooling, cooling for free cooling Rejection tower packing height Z ₁ , cooling tower water / air ratio L / G for free cooling N ₁ , proportional constant C ₂ specific to cooling tower for second refrigerator, for second refrigerator The cooling tower filling height Z ₂ , the cooling tower water-air ratio L / G for the second refrigerator is determined as N _2, and the tower characteristics that can be approximated to obtain the cooling characteristics are shown below. T _w2 calculated for each temperature of air wet bulb flowing in the cooling tower for free cooling by the logarithmic average formula of the tower characteristics and the logarithmic average formula of the cooling tower characteristics for the second refrigerator, and the second refrigerator _Tw3 calculated for each air wet bulb temperature flowing through the cooling tower for
Logarithmic average formula of cooling tower characteristics for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
(U / N) ₁ = C ₁ Z ₁ N ₁ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Logarithmic average formula of cooling tower characteristics for the second refrigerator.

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
(U / N) ₂ = C ₂ Z ₂ N ₂ α ⁻¹ , 0.3 ≦ α ≦ 0.5
The logarithmic average formula of the cooling tower characteristics for free cooling The vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C for free cooling, and the horizontal axis represents the air wet bulb temperature ° C introduced to the free cooling cooling tower In the graph, the _Tw2 calculated for each air wet bulb temperature introduced into the cooling tower for free cooling and the air wet bulb temperature introduced into the cooling tower for the second refrigerator were calculated. Two cooling tower outlet water temperature lines are plotted by plotting T _w3 and connecting the plot points, and the cooling tower outlet water temperature line for the second refrigerator and the free cooling cooling tower on the vertical axis of the graph air wet-bulb temperature ℃ the intersection of the cooling water outlet temperature ℃ the horizontal axis parallel to drawn the T _s isothermal line as the first set value of the outside air wet-bulb temperature, the cooling tower outlet water temperature lines for the free cooling And the free cue on the vertical axis of the graph Characterized by the air wet-bulb temperature ℃ intersections of the T _s temperature line cooling towers cooling water outlet temperature ℃ drawn parallel to the horizontal axis for the ring and the second set value of the outside air wet-bulb temperature .

According to a seventh aspect of the present invention, in the air conditioning equipment according to the second aspect, the control device returns the cooling water going temperature supplied to the precooling coil of the free cooling cooling water circulation path from the precooling coil to T _s . When the cooling water return temperature is T _r , the cooling tower inlet water temperature for free cooling (this is equal to the _Tr temperature) ° C is T _w1 , and the cooling tower outlet water temperature for free cooling is ° C. T _w2 , cooling tower cooling water outlet water temperature ° C for the second refrigerator flowing through the second flow path is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air at T _w2 ° C Enthalpy kJ / kgDA of h _w2 , enthalpy kJ / kgDA of saturated air at T _w3 ° C. h _w3 , proportional constant C ₁ inherent to the cooling tower for free cooling, cooling for free cooling Rejection tower packing height Z ₁ , cooling tower water / air ratio L / G for free cooling N ₁ , proportional constant C ₂ specific to cooling tower for second refrigerator, for second refrigerator The cooling tower filling height Z ₂ , the cooling tower water-air ratio L / G for the second refrigerator is determined as N _2, and the tower characteristics that can be approximated to obtain the cooling characteristics are shown below. According to Chebyshev's formula for tower characteristics, T _w2 calculated for each air wet bulb temperature flowing through the cooling tower for free cooling and T calculated for each air wet bulb temperature flowing through the cooling tower for the second refrigerator seeking _w3 ,
Chebyshev formula for cooling tower characteristics for free cooling U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.

Δh ₁ = t _W2 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 1 = C 1 Z 1 N 1 α -1, 0.3 ≦ α ≦ 0.5
Chebyshev formula for cooling tower characteristics for second refrigerator U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.

Δh ₁ = t _W3 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 2 = C 2 Z 2 N 2 α -1, 0.3 ≦ α ≦ 0.5
A graph in which the vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C for free cooling, and the horizontal axis represents the air wet bulb temperature ° C introduced into the free cooling cooling tower, the free cooling _Tw2 calculated for each air wet bulb temperature introduced to the cooling tower and T _w3 calculated for each air wet bulb temperature introduced to the cooling tower for the second refrigerator are respectively plotted to connect plot points. Two cooling tower outlet water temperature lines are created, and the cooling tower outlet water temperature line for the second refrigerator and the cooling tower cooling water outlet water temperature for free cooling on the vertical axis of the graph are parallel to the horizontal axis. The air wet bulb temperature ° C at the intersection with the drawn T _s temperature line is set as the first set value of the outside air wet bulb temperature, and the free cooling cooling tower outlet water temperature line and the vertical axis of the graph for the free cooling The cooling tower cooling water outlet water temperature in ° C is parallel to the horizontal axis. Characterized by the air wet-bulb temperature ℃ the intersection of the Drawn T _s isothermal line and a second set value of the outside air wet-bulb temperature.

The invention according to claim 8 is the second refrigerator according to any one of claims 4 to 7, wherein C ₂ = C ₁ , Z ₂ = Z ₁ , and N ₂ = N _1. A cooling tower is provided.
The invention according to claim 9 is the air conditioning equipment according to any one of claims 4 to 7, further comprising a cooling tower for a second refrigerator, wherein Z ₂ > Z ₁ and N ₂ <N _1. It is characterized by that.

The invention according to claim 10 is the air conditioning equipment according to any one of claims 1 to 9, wherein the free cooling cooling water circulation path is provided with the liquid pump in a forward path, the liquid pump and the first A first flow meter is provided between the flow path of the cooling water circulating path for free cooling and a branch point on the outgoing path side, and a second flow meter is provided on the return path.
The invention according to claim 11 is the air conditioning equipment according to any one of claims 1 to 9, further comprising an air conditioner provided with a cooling coil connected to the cooling coil.

According to a twelfth aspect of the present invention, in the air conditioning equipment according to the fourth or fifth aspect, the cooling water going-out temperature T _s supplied to the heat exchanger of the cooling water circulation path for free cooling is returned from the heat exchanger. An input device that sets a predetermined value for the cooling water return temperature to _Tr, and the control device includes a first setting value of the outdoor air wet bulb temperature and a second setting of the outdoor air wet bulb temperature. A calculation unit for calculating and calculating a value is stored, and a result of calculating a predetermined value input by the input device, the free cooling switching mechanism, the free cooling cooling tower, the second refrigerator, the first Controlling the cooling tower for the second refrigerator.

The invention according to claim 13 is the air conditioning equipment according to claim 6 or claim 7, wherein the cooling water going-out temperature T _s supplied to the pre-cooling coil of the free cooling cooling water circulation path is returned from the heat pre-cooling coil. An input device for setting a predetermined value for the cooling water return temperature to _Tr, and the control device sets a first set value of the outside air wet bulb temperature and a second set value of the outside air wet bulb temperature; An arithmetic unit for calculating and storing is stored, and as a result of calculating a predetermined value input by the input device, the switching mechanism for free cooling, the cooling tower for free cooling, the second refrigerator, the second refrigerator, Control of a cooling tower for a refrigerator is performed.

According to the present invention, for example, when cooling water that has risen to 23 ° C. by free cooling is cooled to 18 ° C., the time during which free cooling is possible has been extended from 2300 hours to 4400 hours in the climate of Tokyo. Indeed, more than half of the year was available. And the energy saving progressed by extending free cooling time.
In the heat exchange of air and water in the cooling tower, the heat exchanged between the air and water in the cooling tower is proportional to the difference Δh between the enthalpy h of air in the tower and the enthalpy h _w of saturated air at the same temperature as the inlet water temperature. Therefore, even if the height of the cooling tower is increased by using only one cooling tower or the cross-sectional area of the tower perpendicular to the air flow direction is increased, the enthalpy of the air introduced into the portion where the capacity is increased is increased. However, it is difficult to cool the water. By connecting two cooling towers in series, the enthalpy of the inlet air to the part where the capacity is increased as the second is the same as the enthalpy of the first inlet air. Since it is very low, heat exchange in the tower section with increased capacity can be promoted to the maximum.

  When performing free cooling, a dedicated machine was selected based on the rated capacity of the cooling tower for the centrifugal chiller, so the initial cost of the dedicated machine was minimized.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
[First embodiment]
The computer heat generation load of the computer center accounts for 60 to 90% of the total heat load at the peak time, and the outside air and building heat transfer load in other computer rooms are heat loads generated in the summer.
The air conditioning equipment 1 according to the present embodiment is applied when the ratio of outside air and building load to the whole is small.

  As shown in FIG. 1 and FIG. 2, the air-conditioning equipment 1 according to the present embodiment includes a free cooling cooling tower (CT 3) between a free cooling cooling water circulation path 131 and a second cooling water circulation path 134. This is different from conventional air-conditioning equipment in that a free cooling switching mechanism 10 that connects 105 and a cooling tower (CT2) 115 for the second refrigerator in series is provided. Therefore, in this embodiment, the same code | symbol is attached | subjected to the same structure as the conventional air conditioning apparatus, and the description is abbreviate | omitted.

  The free cooling switching mechanism 10 includes a first flow path 11 that connects the forward path 131 a of the free cooling cooling water circulation path 131 and the return path 134 b of the second cooling water circulation path 134, and the free cooling cooling water circulation path 131. A second flow path 12 connecting the outgoing path 131a and the outgoing path 134a of the second cooling water circulation path 134, and a branch point 11a on the outgoing path 134a side of the free cooling cooling water circulation path 131 of the first flow path 11; A first valve (V1) 13 provided in the forward path 131a of the free cooling cooling water circulation path 131 between the free cooling cooling water circulation path 131 of the second flow path 12 and the branch point 12a on the outgoing path 131a side; The second valve (V2) 14 provided in the first flow path 11, the third valve (V3) 15 provided in the second flow path 12, and the second cooling of the second flow path 12 And a fourth valve (V4) 16 which from forward path 134a side of the branch point 12b provided on the second second refrigerator (R2) 109 side of the circulation path 134.

  Further, the forward passage 131a of the cooling water circulation passage 131 for free cooling is provided with a flow meter F1 between the circulation pump (P3) 106 and the branch point 11a. The flow rate controller FIC1 that communicates with the flow meter F1 compares the flow rate from the flow meter F1 with the set flow rate, and adjusts the flow rate of the circulation pump (P3) 106 so that the flow rate becomes 80% of the rated flow rate of the circulation pump (P2) 117. Control the number of revolutions. The return path 131b of the cooling water circulation path 131 for free cooling is provided with a flow meter F2. The flow controller FIC2 that communicates with the flow meter F2 compares the flow rate from the flow meter F2 with the set flow rate, and adjusts the flow rate of the circulation pump (P2) 117 so that the flow rate becomes 80% of the rated flow rate of the circulation pump (P2) 117. Control the number of revolutions.

A control device that performs switching control of the free cooling switching mechanism 10 includes a controller 124 and a calorific value calculation controller 127.
The controller 124 includes a determination unit that determines a setting 1 where the outdoor air wet bulb temperature T1 is 13 ° C. and a setting 2 where the outdoor air wet bulb temperature T1 is 5 ° C. Further, the controller 124, based on the two set values 1 and 2, the second refrigerator (R2) 109, the fan of the cooling tower (CT2) 115 for the second refrigerator, the circulation pump (P2) 117, Circulation pump (CT1) 111, fan for cooling tower (CT3) 105 for free cooling, first valve (V1) 13, second valve (V2) 14, third valve (V3) 15, fourth The operation of the valve (V4) 16 and the circulation pump (P4) 103 is controlled.

  The calorific value calculation controller 127 calculates the calorific value q = Q (T3−T4) based on the temperatures T3 and T4 of the chilled water circulation path 132 and the flow rate Q from the flow meter F3, and determines whether the result is equal to or greater than the set calorific value. The first refrigerator (R1) 108, the fan of the cooling tower (CT1) 114 for the first refrigerator for the first refrigerator, the circulation pump (P1) 116, the circulation pump (CP1) 110, The operation of the second refrigerator (R2) 109, the cooling tower (CT2) 115 for the second refrigerator, the circulation pump (P2) 111, and the circulation pump (CP2) 111 is controlled.

Next, operation | movement of the air conditioning equipment 1 which concerns on this embodiment is demonstrated based on FIG.
First, the air conditioner 101 is operated, the first valve (V1) 13, the second valve (V2) 14, the third valve (V3) 15 and the fourth valve (V4) 16 are closed, The refrigerator (R1) 108, the fan of the cooling tower (CT1) 114 for the first refrigerator, the cooling tower circulation pump (P1) 116, and the circulation pump (CT1) 110 are operated (steps S1 to S3).

Next, the temperature T5 of the air blown from the air conditioner 101 is measured with the thermometer in the underfloor space 121 of the computer room 118, and the valve (VE1) 125 is proportionally adjusted so that the temperature controller TIC5 becomes the set blowing temperature. Control (step S4).
Next, the heat quantity q = Q (T3−T4) (kcal / h) is obtained from the water temperature T3 of the outgoing path 132a of the cold water circulation path 132, the water temperature T4 of the return path 132b, and the flow rate Q of the cold water measured by the flowmeter F3. . Then, the calorific value calculation controller 127 determines whether or not the obtained calorie q is equal to or greater than the set calorie (step S5). If it is less than the set heat amount, the process returns to step S3, and if it is determined that the heat quantity is greater than the set heat amount, the process proceeds to step S6.

Next, the outside air wet bulb temperature T1 measured by the outside air wet bulb thermometer is input to the controller 124 via the temperature controller TIC1. The controller 124 determines whether the temperature is lower than 13 ° C. (step S6). If the outdoor wet bulb temperature T1 is 13 ° C. or higher, the process proceeds to step S26, and if the outdoor wet bulb temperature T1 is less than 13 ° C., the process proceeds to step S7.
Next, the outside air wet bulb temperature T1 measured by the outside air wet bulb thermometer is input to the controller 124 via the temperature controller TIC1. The controller 124 determines whether or not the outdoor wet bulb temperature T1 is less than 5 ° C. (step S7). If the outdoor wet bulb temperature T1 is 5 ° C. or higher, the process proceeds to step S18, and if the outdoor wet bulb temperature T1 is less than 5 ° C., the process proceeds to step S8.

  Next, when the outdoor wet bulb temperature T1 is less than 5 ° C., the first valve (V1) 13 is opened, the second valve (V2) 14, the third valve (V3) 15 and the fourth valve. (V4) 16 is closed, the fan of the cooling tower (CT3) 105 for free cooling is operated, and the circulation pump (P3) 106 and the circulation pump (P4) 103 are operated. The rotational speed of the circulation pump (P3) 106 is controlled so that the flow rate measured by the flow meter F1 becomes 80% of the rated flow rate of the circulation pump (P2) 117 (steps S8 to S10).

Next, the temperature regulator TIC7 proportionally controls the valve (VE2) 126 so that the outlet air temperature T7 from the precooling coil 102 of the air conditioner 101 becomes the preset precooled water outlet air temperature (step S11).
Next, it is determined whether or not the cooling water temperature T6 of the cooling tower (CT3) 105 for free cooling is lower than 5 ° C. (step S12). When the cooling water temperature T6 is less than 5 ° C., the fan of the cooling tower (CT3) 105 for free cooling is stopped (step S13). When the cooling water temperature T6 is 5 ° C. or higher, the process returns to step S7.

Next, it is determined whether or not the cooling water temperature T6 of the cooling tower (CT3) 105 for free cooling is 5 ° C. or higher (step S14). When the cooling water temperature T6 is less than 5 ° C., the process returns to step S13.
Next, it is determined whether or not the outdoor wet bulb temperature T1 is 5 ° C. + 0.5 ° C. or higher (step S15). If the outdoor wet bulb temperature T1 is less than 5 ° C. + 0.5 ° C., the process returns to step S8. When the outdoor wet bulb temperature T1 is 5 ° C. + 0.5 ° C. or higher, the process proceeds to Step 16.

Next, the fan of the cooling tower (CT3) 105 for free cooling, the circulation pump (P3) 106, and the circulation pump (P4) 103 are stopped (step S16).
Next, it is determined whether to stop the air conditioner 101 (step S17). When stopping, it progresses to step S31. If not stopped, the second valve (V2) 14 and the third valve (V3) 15 are opened and the first valve (V1) 13 and the fourth valve (V4) are opened as in the negative of step S7. 16 is closed (step S18).

  Next, the fan of the cooling tower (CT2) 115 for the second refrigerator and the fan of the cooling tower (CT3) 105 for free cooling are operated, and the circulation pump (P2) 117, the circulation pump (P3) 106, The circulation pump (P4) 103 is operated. The rotational speed of the circulation pump (P3) 106 is controlled so that the flow rate measured by the flow meter F1 is 80% of the rated flow rate of the circulation pump (P2) 117, and the flow rate measured by the flow meter F2 is the circulation pump (P2 ) The rotational speed of the circulation pump (P2) 117 is controlled so as to be 80% of the rated flow rate of 117 (steps S19 to S21).

Next, the temperature controller TIC7 proportionally controls the valve (VE2) 126 so that the outlet air temperature T7 from the precooling coil 102 of the air conditioner 101 becomes the preset precooled water outlet air temperature (step S22).
Next, it is determined whether or not the outdoor wet bulb temperature T1 is 13 ° C. + 0.5 ° C. or higher (step S23). When the outdoor wet bulb temperature T1 is less than 13 ° C. + 0.5 ° C., the process returns to step S7. When the outdoor wet bulb temperature T1 is 13 ° C. + 0.5 ° C. or higher, the process proceeds to step S24.

Next, the fan of the cooling tower (CT2) 115 for the second refrigerator, the fan of the cooling tower (CT3) 105 for free cooling, the circulation pump (P2) 117, the circulation pump (P3) 106, and the circulation pump (P4) ) 103 is stopped (step S24).
Next, it is determined whether to stop the air conditioner 101 (step S25). When stopping, it progresses to step S31. If not stopped, the fourth valve (V4) 16 is opened and the first valve (V1) 13, the second valve (V2) 14, and the third valve (V3) 15 are opened as in the negative of step S6. Is closed (step S26).

Next, the second refrigerator (R2) 109, the fan of the cooling tower (CT2) 115 for the second refrigerator, the circulation pump (P2) 117, and the circulation pump (CP2) 111 are operated (step S27).
Next, it is determined whether the heat quantity q is equal to or less than a set value (step S28). If the amount of heat is greater than or equal to the set value, the process returns to step S6.

Next, when the amount of heat is not more than the set value, the second refrigerator (R2) 109, the fan of the cooling tower (CT2) 115 for the second refrigerator, the circulation pump (P2) 117, the circulation pump (CP2) ) 112 is stopped (step S29).
Next, it is determined whether to stop the air conditioner 101 (step S30). When stopping, it progresses to step S31. When not stopping, it returns to step S5.

Next, the air conditioner 101 is stopped, the first refrigerator (R1) 108, the fan of the cooling tower (CT1) 114 for the first refrigerator, the circulation pump (P1) 116, and the circulation pump (CP1) 111 are turned on. Stop (step S32).
Next, the first valve (V1) 13, the second valve (V2) 14, the third valve (V3) 15, and the fourth valve (V4) 16 are closed (step S33).

As described above, the operation of the air conditioning equipment 1 is controlled.
Next, the summer operation will be described with reference to FIG. Here, in the summer, the outside air wet bulb temperature was set to 13 ° C. or higher, and the temperature controller TIC 1 was set to 1 or higher (4360 hours per year in Tokyo weather data). Here, since free cooling by the free cooling cooling tower 105 is not performed, the free cooling cooling tower (CT3) 105, the circulation pump (P3) 106, the heat exchanger 104, the circulation pump (P4) 103, The precooling coil 102 is omitted.

  In the summer, the cooling tower (CT3) 105 for free cooling is operated so that the precooled water inlet water temperature does not reach the outside air wet bulb temperature at which the set condition (in this case, 20 ° C.) can be established. Thus, the first valve (V1) 13, the second valve (V2) 14, the third valve (V3) 15 are closed, the fourth valve (V4) 16 is opened, and the free cooling cooling tower ( CT3) 105 and the cooling tower circulation pump (P3) 106 are stopped, and the precooling circulation pump (P4) 103 is also stopped. Since the indoor heat load increases in summer, for example, the cooling coil 107 at the rear stage of the air conditioner 101 also eliminates the cooling of the precooling, so the first refrigerator (R1) 108 and the pump that have been operated so far In addition to (CP1) 110, the second refrigerator (R2) 109 and the pump (CP2) 111 are operated to increase the amount of water in the subsequent cooling coil 107.

  Next, the operation in the interim period will be described based on FIG. In the interim period, the outside wet bulb temperature was set to 5 ° C. or more and less than 13 ° C., and the temperature controller TIC 1 was set to less than 1 setting 2 or more (2100 hours per year in Tokyo weather data). In addition, since operation by the 2nd refrigerator (R2) 109, the circulation pump (CT2) 111, and the circulation pump (P2) 117 is not performed here, these are abbreviate | omitted.

  In this season, when only the cooling tower 105 for free cooling is operated, the temperature of the cooling water in the outgoing path 131a of the cooling water circulation path 131 for free cooling does not become 18 ° C. or lower, so as shown in step S18 of FIG. By setting a cooling tower (CT3) 105 for free cooling and a cooling tower (CT2) 115 for the second refrigerator in series, setting 1 (13 ° C.) of the outdoor wet bulb temperature T1 at a water temperature of 18 ° C. or less To do.

  The cold water in the precooling water circulation path 130 heated by exchanging heat with the indoor circulation air by the precooling coil 102 is conveyed to the heat exchanger 104 and exchanges heat with the cooling water in the free cooling cooling water circulation path 131. The cooling water is conveyed to a free cooling cooling tower (CT3) 105 by a circulation pump (P3) 106, and the first free cooling cooling tower (CT3) 105 has a wet bulb temperature and a cooling tower at that time. The water is cooled to a temperature close to the set water temperature of 18 ° C. depending on the relationship of the capacities. This cooling water is conveyed to the cooling tower (CT2) 115 for the second stage second refrigerator through the first flow path 11. In the cooling tower (CT 2) 115 for the second stage second refrigerator, the cooling water cooled in the first stage is cooled to a set water temperature of 18 ° C. or less, and heat is exchanged again through the second flow path 12. To the container 104. At this time, in the latter stage chilled water coil 107, the building load is eliminated and the outside air cooling load is eliminated in the intermediate period, so that the indoor load is small. The cooling of the first refrigerator (R1) 108 can cover the chilled water pump (CP1) 110. A part of the cold water transported in is introduced, and the air is cooled to a set room temperature of 26 ° C.

Next, the winter operation will be described with reference to FIG. Here, the outdoor wet bulb temperature was less than 5 ° C. in winter (2300 hours per year in Tokyo weather data).
In this season, the setting is 2 (5 ° C.) for setting the outside air wet bulb temperature T1 at a cooling water temperature of 18 ° C. or lower, so that the first valve (V1) 13 is opened as shown in step S8 of FIG. The second valve (V2) 14, the third valve (V3) 15, and the fourth valve (V4) 16 are closed, and a cooling tower (CT3) 105 for free cooling and a circulation pump (P3) 106 for the cooling tower. And the pre-cooling circulation pump (P4) 103 are operated. The cold water heated by exchanging heat with the indoor circulation air by the pre-cooling coil 102 of the air conditioner 101 is conveyed to the heat exchanger 104 and exchanges heat with the cooling water. This cooling water is conveyed to a cooling tower (CT3) 105 for free cooling by a circulation pump (P3) 106. The conveyed cooling water is cooled to a cooling water set water temperature of 18 ° C. or lower by a cooling tower (CT 3) 105 for free cooling, and is again conveyed to the heat exchanger 104. In the chilled water coil 107 at this time, the building load is eliminated in the winter, and the outside air cooling load is also eliminated, so that the indoor load is small and the cooling of one chiller can cover the chilled water conveyed by the chilled water pump (CP1) 110. A part is introduced and the air is cooled down to the set room temperature.

As described above, according to the present embodiment, the cooling tower (CT2) 115 for the second refrigerator and the cooling tower (CT3) 105 for free cooling that are idle due to the low heat load in the winter or intermediate period are connected in series. Since it can cool in two steps by arrange | positioning to, cold water temperature can be lowered | hung conventionally.
In this embodiment, the capacity of the heat source equipment is 400 RT per refrigerator, and the cooling tower is rated operation 520 RT when manufacturing cooling water for the refrigerator. When this cooling tower performs free cooling, 80% water operation is sufficient (reduction of cooling heat for compressor work).

Two cooling towers (CT2) 115 for the second freezer when the indoor heat load is reduced in the intermediate period or winter season are arranged in series, and the cooling water of 23 ° C. is 20 in the first unit. Cooling to 20 ° C., cooling water at 20 ° C. was cooled to 18 ° C. in the second unit. The wet bulb temperature at that time is 13 ° C. or less.
Next, a theory will be described in which the cooling tower (CT2) 115 for the second refrigerator and the cooling tower (CT3) 105 for free cooling, which are idle due to a low heat load in the winter or intermediate period, are cooled in series.

Here, the floor blowing temperature of the computer room 118 is set at 17 to 20 ° C. This is suppressed in this range because the computer 119 dislikes condensation. The temperature of the return air of the air conditioner 101 rises by about 1 ° C. in the return duct via the room and returns at 24-27 ° C.
1. The pre-cooling water that cools the return air of the air conditioner 101 has a larger heat transfer area of the pre-cooling coil 102 in the air conditioner 101 and a larger initial cost as the temperature difference between the air and water becomes smaller. And running costs also increase. Also, the space will increase and the initials will increase.

  As the cooling tower (CT3) 105 for free cooling, since the cooling tower water supply temperature becomes high, the annual usage time increases and the running cost decreases. The temperature difference ΔT between air and precooling water is determined based on the balance between the running cost and the initial cost, and the precooling coil 102 is selected. In this embodiment, since the balance was good when ΔT = 2 ° C., the return water temperature of the pre-cooling water heat exchanger 104 was set to 25 ° C. with respect to the return air temperature of 27 ° C. of the air conditioner 101.

  2. Since the return cooling water temperature of the pre-cooling water heat exchanger 104 has been determined, the forward temperature of the pre-cooling water heat exchanger 104 is determined. If the temperature difference between the inlet and outlet of the precooling water is small, the amount of water to be transferred becomes large, the precooling coil 102 in the air conditioner 101 becomes large, the initials increase, and the running cost also increases. The difference is determined at 5-7 ° C. In the present embodiment, the temperature difference is 5 ° C. and is 20 ° C.

  3. 1. Supply water temperature of pre-cooled water In the heat exchanger 104, it is desired to use the cooling water of the cooling tower 105 for free cooling as high as possible. The cooling water temperature is determined according to the temperature at which the pre-cooling water supply temperature can be taken out. At this time, the difference between the pre-cooling water supply temperature and the cooling water supply temperature is determined based on the balance between the running cost and the initial cost, but even the minimum temperature difference of 1 to 2 ° C. is not so large and affected by the initial cost. In this embodiment, the temperature difference between the precooling water and the cooling water is 2 ° C., the cooling water outlet water temperature (cooling tower inlet water temperature) of the heat exchanger 104 is 23 ° C., and the heat exchange is performed with respect to the precooling water return water temperature of the heat exchanger 104. The cooling water inlet temperature (cooling tower outlet water temperature) of the heat exchanger 104 is set to 18 ° C., and the cooling water inlet / outlet temperature difference is set to 5 ° C. with respect to the pre-cooling water going water temperature of the condenser 104.

4). The cooling tower 105 for free cooling has a cooling capacity of one or more freezers that produce idle water or main cold water.
To summarize from the above, as provisional conditions for free cooling, the cooling water inlet temperature 23 ° C. of the cooling tower 105 for free cooling and the cooling water outlet temperature 18 ° C. of the cooling tower 105 for free cooling could be provisionally defined. .

The following shows that the first set value and the second set value based on the outside wet bulb temperature can be defined by the two curves in FIG. In order to obtain the two curves in FIG. 9, the following is developed using FIG. 7 and the equation of U / N.
First, an overview of serial cooling of two cooling towers will be described.
The amount of heat exchanged between the cooling tower air and water is proportional to the difference Δh between the enthalpy h of air and the enthalpy hw of saturated air at the same temperature as the inlet water temperature, and cooling is performed below the enthalpy h of air and the wet bulb temperature t ′. Is impossible. In other words, if the water is not heated, it can be cooled to near the wet bulb temperature. The state of water and air when two cooling towers are cooled in series is shown in FIG. Here, if the water at the water temperature of one cooling tower is cooled, the cooling heat amount of the cooling tower is equal to the heat balance of the amount of heat the water receives from the coil of the air conditioner or device, and the cooled water is wet. The ball temperature is not reached and the water temperature t _W1 and the wet bulb temperature t ₁ ′ are in the middle. In addition, the air at this time exchanges heat, so that the closer to the outlet, the enthalpy increases and the wet bulb temperature rises. Even if the height of the cooling tower is increased and the number of exchangers is increased, there is no effect. Therefore, when the water cooled in the first unit is further cooled in another cooling tower, it becomes possible to exchange heat with air having a low wet bulb temperature by taking in fresh air (outside air), and the water temperature t _W2 cooled in the previous stage The following state can be obtained.

Next, calculation in series with two cooling towers will be described.
Various symbols used for calculation are determined as follows.
t _w1 = first cooling tower cooling water inlet water temperature [° C]
t _w2 = cooling water outlet water temperature of the first cooling tower [° C]
t _w3 = cooling water outlet water temperature of the second cooling tower [° C]
h _w1 = Saturated air enthalpy of the first cooling tower cooling water inlet water temperature [kJ / kgDA]
h _w2 = Saturated air enthalpy of the first cooling tower cooling water outlet water temperature [kJ / kgDA]
h _w3 = Saturated air enthalpy of the second cooling tower cooling water outlet water temperature [kJ / kgDA]
h ₁ = 1st and 2nd cooling tower inlet air enthalpy [kJ / kgDA]
h ₂ = the first cooling tower outlet air enthalpy [kJ / kgDA]
h ₃ = 2nd cooling tower outlet air enthalpy [kJ / kgDA]
Cρ = specific gravity of water [kJ / kg]
Ka = enthalpy standard overall area heat transfer coefficient [kJ / m ² · ΔI · h]
C = Proportional constant specific to cooling tower L = Circulating water volume [kg / h]
G = cooling tower airflow [kg / h]
A = Tower cross section perpendicular to the direction of air flow [m ² ]
Z = height of packing [m]
α, β = constant determined by packing N = water / air ratio L / G
X = approximately calculated tower characteristic U / N
Y ₁ = tower characteristic U / N calculated by logarithmic average method
Y ₂ = Tower characteristic U / N calculated by Chebyshoff formula
The cooling of water by the cooling tower is different from the cooling of a general heat exchanger, and heat exchange is performed by direct contact between water and air. Therefore, not only sensible heat transfer but also water vapor transfer occurs, resulting in complicated analysis. However, since the evaporation amount of the cold water with respect to the cooling tower is as small as less than 1%, the transferred water vapor flow rate is negligible. Therefore, the amount of heat given to the atmosphere by the cooling water of the cooling tower and the amount of heat Q of the heat balance by which the cooling water is cooled are given by the following equations.

dQ = G × (dh) = (− Cρ) × L × (dT _w ) (1)
FIG. 8 shows the relationship between the inlet water temperature t _w1 , the outlet water temperature t _w2 , the inlet air wet bulb temperature t ₁ ′, the outlet air wet bulb temperature t ₂ ′ and the specific enthalpy in the _counterflow type cooling tower. Indicates the state of heat exchange. The inlet air changes with a gradient line (operation line) which is L / G. Also, when considering the heat exchanger for small height dZ of counterflow cooling towers, small amount of heat exchange Q in the minute height, and the water temperature t saturated air ratio enthalpy of _w equal temperature h _w in that part It is proportional to the difference (h _w −h) from the specific enthalpy h of air and is given by the following equation.

dQ = Ka × (h _w −h) × dZ × A (2)
Equation (3) is obtained from equations (1) and (2).
dQ = G × (dh) = (− Cρ) × L × (dT _w ) = Ka × (h _w −h) × dZ × A (3)
Equation (3) is modified to obtain equations (4) and (5).

Ka × dZ × A / G = (dh) / (h _w −h) (4)
Ka × dZ × A / L = (− Cρ) × (dT _w ) / (h _w −h) (5)
When the equations (4) and (5) are integrated with respect to the packing height Z, the equations (6) and (7) are obtained.

Equations (6) and (7) are basic equations of the counter-flow cooling tower, U is the number of moving units, and N ₀ is a numerical value replaced with the initial value of L / G. U / N is called tower performance factor. The calculation method is approximated by calculating the average value of the variables in the integral symbol of equation (7). Representatively, in the case of the logarithmic average method and Chebyshev's formula (appropriately divided into four, 1 / ( In the case of calculating the average value of h _w −h), U and U / N can be obtained.

  The case of the logarithmic average method is shown in equation (8).

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
In the case of using Chebyshev's formula, the calculation result is shown in the equation (9) as in the case of the logarithmic average method.

U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )} (9)
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W2 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W -H) value Δh ₄ = t _W2 -0.1 Δt _W value (h _W -h) The thermal characteristic Ka is a numerical value representing the performance of the packing material, and the theory is that the flow of water and air in the tower is complicated. It is difficult to ask for. Therefore, Ka is obtained in advance by an empirical formula for each packing, and the empirical formula is obtained by formula (10) as a function of (L / A) and (G / A).

Ka = C (L / A) α (G / A) β ... (10)
Here, α + β≈1.
Substituting equation (10) into U / N in equation (7) yields equation (11).
U / N = Ka × A × Z / L = CZ [L / A] α ⁻¹ [G / A] ^{− (} α ⁻¹⁾ = CZNα ⁻¹
(11)
Here, when CZ is set as a constant K, equation (12) is obtained.

U / N = KNα ⁻¹ (12)
If the cooling tower manufacturer's rated capacity value is known, U / N is obtained and N and K are obtained. α takes around 0.4, and U / N in the equation (12) is obtained.
(For example, N = L / G is obtained from the cooling tower of rated water volume L, rated air volume G, rated outdoor wet bulb temperature t ₁ ′, rated inlet water temperature t _W1 , outlet water temperature t _W2 , and rated water temperatures t _W1 , t with the h ₁ and calculated values h ₂ from the rated rated outside air wet-bulb temperature of _W2 (8) and calculated back expression leads to K = cooling tower seeking U / N.)
Here, the value obtained by changing the tower characteristic U / N obtained by the equation (12) and the inlet water temperature _tw1 by 0.1 ° C. is substituted into _tw2 of the equation (8) or (9), and the U / N can be obtained as a calculation result points t _w2 such are equal.

The _tw2 obtained from the above is the water temperature at the outlet of the first cooling tower.
Next, the outlet water temperature t _W3 of the second cooling tower is obtained. The state of water and air in series of two cooling towers is shown in FIG. Here, since the outlet water temperature t _W2 of the first cooling tower becomes the inlet water temperature of the second cooling tower, each temperature state of the formula (8) or the formula (9) is replaced as follows.
t _W1 → t _W2
t _W2 → t _W3
h _W1 → h _W2
h _W2 → h _W3
h ₂ → h ₃
Therefore, the approximate expression of U / N is the expression (13) in the case of the logarithmic average method, and the expression (14) in the case of the Chebyshev formula.

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
In the case of using Chebyshev's formula, the calculation result is described in the equation (14) as in the case of the logarithmic average method.

U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )} (14)
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W3 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W -H) value Δh ₄ = t _W2 -0.1 Δt _W (h _W -h) value Further, the tower characteristic U / N according to the equation (12) of the second cooling tower is obtained. N and K values vary depending on the capacity of the second cooling tower. If the capacity is the same as that of the first cooling tower, the N and K values will be the same, so that the tower characteristic U / N and the inlet water temperature _tw2 determined by the equation (12) are 0.1 as in the first cooling tower. A value changed by ° C. was substituted for _tw3 in the equation (13) or (14), and a point _{tw3 at} which U / N becomes equal was attached as a calculation result.

The _tw3 obtained from the above is taken as the second cooling tower outlet water temperature.
FIG. 9 shows the relationship between the outdoor wet bulb temperature and the outlet water temperature when the inlet water temperature of the first cooling tower in series of two cooling towers of the same capacity is 23 ° C. The outside air wet bulb temperature at which the cooling water outlet water temperature of 18 ° C. can be taken out is 5 ° C. or less in one cooling tower, which is 2300 hours or less per year in Tokyo weather data. However, in the case of two cooling towers in series, the outside wet bulb temperature may be 13 ° C. or less, and the Tokyo weather data was 4400 hours per year.

  In this embodiment, the chart shown in FIG. 9, that is, the coordinates where the outlet water temperature is the vertical axis and the outdoor wet bulb temperature is the horizontal axis, is defined by the outlet temperature of the free cooling cooling tower 105 and the outdoor wet bulb temperature. A first diagram (one cooling tower), a cooling tower 105 for free cooling, and a cooling tower 115 for a second refrigerator are connected in series by the switching control of the free cooling switching mechanism 10; A chart obtained by fitting the second diagram (two cooling towers in series) defined by the outside wet bulb temperature is stored in the control device.

That is, when the cooling water supply temperature supplied to the heat exchanger of the free cooling cooling water circulation path is T _s and the return temperature of the cooling water returning from the heat exchanger is T _r , the cooling tower cooling water for free cooling The inlet water temperature (which is equal to the _Tr temperature) ° C is T _w1 , the cooling tower cooling water outlet water temperature ° C is T _w2 , and the cooling tower cooling water outlet water temperature ° C for the second refrigerator flowing through the second channel is T saturating air enthalpy kJ / kgDA at _w3 , T _w1 ℃ h _w1 , enthalpy kJ / kgDA of saturated air at T _w2 ℃ h _w2 , enthalpy kJ / kgDA of saturated air at T _w3 ℃ h _w3 , for free cooling Specific constant C ₁ of the cooling tower, the height Z ₁ of the cooling tower packing for free cooling, the cooling tower water / air ratio L / G for free cooling N ₁ , the cooling tower specific for the second refrigerator Proportional constant C ₂ , second The cooling tower filling height Z ₂ for the refrigerator and the cooling tower water-to-air ratio L / G for the second refrigerator can be approximated by N _{2. Tw2} calculated for each temperature of the air wet bulb flowing through the cooling tower and the temperature of the air wet bulb flowing through the cooling tower by the logarithmic average formula of the cooling tower characteristics for the second refrigerator and the logarithmic average formula of the cooling tower characteristics for the second refrigerator T _w3 calculated every time is a graph in which the vertical axis represents the cooling tower cooling water outlet water temperature ° C for free cooling, and the horizontal axis represents the temperature of air wet bulb flowing through the free cooling cooling tower ° C. _Tw2 and _Tw3 are plotted and two cooling tower outlet water temperature lines are created by connecting the plot points. The cooling tower outlet water temperature line for the second refrigerator and the cooling tower for free cooling on the vertical axis of the graph. empty intersection of the cooling water outlet temperature ℃ the horizontal axis parallel to drawn the T _s temperature line Set the air / wet bulb temperature ° C as the first set value of the outside air / wet bulb temperature, and set the cooling tower outlet water temperature line for free cooling and the cooling tower outlet water temperature ° C for free cooling on the vertical axis of the graph in parallel with the horizontal axis. A chart in which the air wet bulb temperature ° C at the intersection with the drawn T _s temperature line is the second set value of the outdoor wet bulb temperature is stored in the control device.

   Logarithmic average formula of cooling tower characteristics for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
(U / N) ₁ = C ₁ Z ₁ N ₁ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Logarithmic average formula of cooling tower characteristics for the second refrigerator.

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
(U / N) ₂ = C ₂ Z ₂ N ₂ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Also, a chart in which the logarithmic average method is replaced with the Chebyshev formula may be used.

T _s , T _r , C ₁ , Z ₁ , N ₁ , C ₂ , Z ₂ , N ₂ , α, etc. can be set to predetermined values by an input device such as a keyboard or a numeric keyboard connected to the control device, Under this condition, calculation can be performed for each outdoor wet bulb temperature of T _w2 and T _w3 to obtain the first set value of the outdoor wet bulb temperature and the second set value of the outdoor wet bulb temperature. is there.
Here, when a predetermined value (for example, T _s = 18 ° C., T _r = 23 ° C. as shown in FIG. 9) is set to the above condition value by the input device, the control device sets the T _s setting. Between the first set value of the outside air wet bulb temperature and the second set value of the outside wet bulb temperature at each intersection of the value and the first diagram and the second diagram (see FIG. 9 is between 5 ° C. and 13 ° C.), the switching control of the free cooling switching mechanism 10 is performed so that the cooling tower 105 for free cooling and the cooling tower 115 for the second refrigerator are connected in series. .

Next, the case where the capacity of the second cooling tower is large will be described. If the same amount of water as the first unit is passed through a cooling tower with a large capacity of the second unit, the amount of water L does not change. However, since the amount of air G is large, N is small and the tower characteristic (12) equation U / N is large. That is, a cooling tower for the second refrigerator that satisfies Z ₂ > Z ₁ and N ₂ <N ₁ is provided. Therefore, the exit temperature _tw3 of the second cooling tower in the approximate expression (13) or (14) can be lowered. Considering this tendency, the N and K values of the second cooling tower are newly obtained, and two units are obtained by the tower characteristics (12) and the approximate expression (13) or (14) in the same manner as described above. The eye cooling tower outlet temperature _tw3 can be calculated.

  FIG. 10 shows the relationship between the outside air wet bulb temperature at the cooling tower inlet water temperature of 23 ° C. and the cooling tower outlet temperature when the capacity of the second cooling tower is 1.0 to 2.0 times. If the capacity of the second cooling tower is the same as the capacity of the first cooling tower, an outside air wet bulb temperature of less than 13 ° C is required to bring the cooling tower outlet water temperature to 18 ° C. If the capacity of the second cooling tower is twice the capacity of the first one, the temperature of the outside wet bulb temperature should be less than 15 ° C. there were.

  Since the return temperature of the air conditioner varies depending on the indoor temperature condition or the underfloor blowing temperature condition, the precooling water temperature condition and the cooling water temperature condition vary. Next, when the cooling water inlet water temperature is 21 ° C. instead of 23 ° C. and the water must be fed to the heat exchanger at 16 ° C., the relationship between the outside wet bulb temperature and the cooling tower outlet water temperature in FIG. It becomes. When the capacity of the second cooling tower is the same as that of the first cooling tower, it was necessary to have an outdoor wet bulb temperature of less than 11 ° C to bring the cooling tower outlet water temperature to 16 ° C. If the capacity of the second cooling tower was twice the capacity of the first one for 3600 hours, the outside wet-bulb temperature should be less than 13 ° C., and it was 4400 hours.

  As a result, the annual free cooling operation time can be extended by connecting two cooling towers in series, and the free cooling operation time can be extended by increasing the cooling tower capacity, thereby reducing annual energy consumption and reducing running costs. These systems are actually determined by balancing the initial cost increase due to the cooling tower capacity increase and the running cost reduction due to the long free cooling.

Next, the optimum value for the division of the refrigerator in this embodiment will be described.
The number of refrigerators is determined so that the initial increase divided by the running effect when divided is collected within five years. However, sufficient consideration should be given to risk dispersion. The running effect is that the refrigerator that cools the heat load such as outside air and building heat transfer load can be stopped in the middle and winter seasons, or the most efficient partial load when the refrigerator is highly efficient against partial load. It is planned to be able to drive at. It is determined to be 2 to 3 units or more with respect to the total heat load.

Next, the cooling capacity and equipment design conditions of the cooling tower (CT3) 105 for free cooling will be described.
Reduction of running cost of all heat source equipment due to cooling effect of cooling tower (CT3) 105 for free cooling, power consumption of fan and circulating pump (P3) 106 of cooling tower (CT3) 105 for free cooling, and free cooling In consideration of the increase in initial cost due to the provision of the cooling tower (CT3) 105, the cost is determined so that it can be recovered within five years in terms of cost. The effect of reducing the running cost is that the second refrigerator (R2) 109 can be stopped when the cooling water of the cooling tower (CT3) 105 for free cooling cools the precooled water and precools the air. For this purpose, it is determined that the cooling capacity is the same as that of at least one refrigerator and at most half the total number of refrigerators with respect to the load. In determining the cooling water temperature, the return temperature of the air conditioner 101 varies depending on the indoor air temperature condition, and the pre-cooling water that can cool the return air is set to the cooling water temperature that can be cooled in combination with the heat exchanger 104.

In this embodiment, the blowing temperature to the underfloor space 121 of the computer room 118 is set to 18 to 20 ° C. (20 ° C. in the present embodiment) in order to prevent condensation of the computer 119. The return air temperature from the air conditioning room 123 rises by about 1 ° C. in the duct through the room and returns at 25 to 27 ° C. (in this embodiment, 27 ° C.).
1) If the temperature difference ΔT between the air and the precooling water is small, the heat transfer area of the coil in the air conditioner 101 increases and the initial cost increases as the precooling water for cooling the air increases. Increases resistance and running costs. Also, the space will increase and the initials will increase. The cooling tower (CT3) 105 for free cooling has a higher cooling tower water supply temperature, so that the annual use time is increased and running is advantageous. The temperature difference ΔT between the air and the precooling water is determined by the balance between the running cost and the initial.

2) If the temperature difference between the inlet and outlet of the pre-cooling water is small, the amount of water transported increases, initials increase, and running also increases. Therefore, the temperature difference ΔTa is set to 5 to 7 ° C.
3) When the feed temperature of the precooling water is determined in 2), the cooling water for the free cooling cooling tower (CT3) 105 is used as high as possible in the cooling water. Therefore, the precooling water feed temperature determined in 2) in the heat exchanger 104 The cooling water temperature is determined according to the temperature that can be taken out. At this time, the difference between the pre-cooling water supply temperature and the cooling water supply temperature is determined by the balance between running and initial, but even the minimum temperature difference of 1 to 2 ° C. is not significantly affected.

  Here, when the return air temperature of 27 ° C. is cooled, the temperature difference ΔT between the pre-cooling water and the air needs to be 2 ° C. or more, so that the upper limit of the pre-cooling water outlet water temperature from the air conditioner 101 is 25 ° C. or less. If the inlet / outlet water temperature difference is ΔTa = 5 ° C., the pre-cooled water inlet water temperature is 20 ° C. In order to cool the precooling water inlet water temperature to 20 ° C., the water temperature at the cooling water inlet of the heat exchanger 104 was set to 18 ° C. With this as a design condition, a cooling tower (CT3) 105 for free cooling is determined.

  In the present embodiment, the temperature of the computer room 120 is 27 ° C. (air conditioner return temperature 27 ° C.), and the cooling capacity of the cooling tower (CT3) 105 for free cooling is 1375 kW (400 RT for the refrigerator). In addition, the water flow meter F1 is 4000 L / min, the wet bulb temperature T1 is 5 ° C., the outlet air temperature T7 of the pre-cooling coil 102 is 23.5 ° C., and the cold water temperature T6 of the cooling tower (CT3) 105 for free cooling is 18 ° C. Met.

Next, the ratio of the pre-cooling coil 102 and the cooling coil 107 of the air conditioner 101 will be described.
The ratio of the cooling capacity of the pre-cooling coil 102 in the air conditioner 101 is determined by setting the cooling capacity of the cooling tower (CT3) 105 for free cooling as 50% of the total heat load in this embodiment. The capacity of the coil 107 is 50% or more. The upper limit is that when the number of rows of precooling coils 102 increases, the inlet precooling water temperature and the outlet air temperature can be brought closer to each other. Decide in consideration of the increase in power consumption.

  The inlet water temperature of the precooling coil 102 (the feed water temperature from the circulation pump (P4) 103) is 20 ° C. determined by the cooling tower (CT3) 106 for free cooling, and the cooling coil of the precooling coil 102 is the cooling coil of the air conditioner 101. When the cooling capacity is 50% of the capacity, the capacity of the pre-cooling coil 102 is determined so that the intermediate air temperature between the air inlet temperature 27 ° C. and the outlet temperature 20 ° C. of the air conditioner 101 is exactly 23.5 or less.

Next, the relationship between the free cooling cooling tower (CT3) 105 and the second cooling tower (CT2) 115 for the second stage will be described.
The cooling tower for free cooling (CT3) 105 has the same cooling capacity as the second turbo refrigerator (R2) 109, and the second cooling tower for the second refrigerator (CT2) 115 is a turbocharger in summer. In order to cool the cooling water for the second refrigerator (R2) 109, a capacity of 520RT that combines the cooling heat amount of the second refrigerator (R2) 109 and the compressor work heat equivalent is required. Therefore, since the capacity of the free-cooling cooling tower (CT3) 105 connected in series is 400 RT, 400 RT / 520 RT = 0.8 at the time of free cooling, and the water amount is 80%. In this case, since the heat transfer area is large with respect to the dedicated machine, it is advantageous for cooling and the conveyance power may be small.

(Second embodiment)
The air-conditioning equipment 1A according to the present embodiment is applied when the ratio of outside air and building load to the whole is large.
Therefore, in this embodiment, as shown in FIG. 12, an air conditioner 20 for cooling the outside air heat load is newly installed in the air conditioning chamber 123 of the computer room 118, and the computer load refrigerator 140 and the cooling unit are cooled. Tower 141 was installed.

  The air conditioner 20 has a cooling coil 21 and communicates with the forward header 112, the return header 113, and the pump 144 via the forward path 22 and the return path 24 that communicate with the forward path 132 a of the chilled water circulation path 132. . Further, a valve 23 is provided in the outgoing path 22. Like the valve 125, the valve 23 is proportionally controlled in the underfloor space 121 of the computer room 118 based on the blown air temperature T5.

A cooling tower 141 and a circulation pump 142 communicate with the refrigerator 140 for computer load via a cooling water circulation path 143.
As described above, according to the present embodiment, as in the first embodiment, the cooling tower (CT2) 115 for the second refrigerator that is idle due to the low heat load in the winter or intermediate period and the free cooling Since the cooling tower (CT3) 105 can be cooled in two stages by arranging the cooling tower (CT3) 105 in series, the chilled water temperature can be lowered than before.

  In the present embodiment, the ratio of the cooling capacity of the pre-cooling coil 102 in the air conditioner 20 is that the cooling capacity of the cooling tower (CT3) 105 for free cooling is 50% or more of the computer heat load (37. 5%), and the upper limit is that when the number of rows of the precooling coils 102 increases, the inlet precooling water temperature and the outlet air temperature can be approached, but the pressure on the blower in the air conditioner 101 due to the increase in the number of rows of the precooling coils 102 Determined considering the increase in power consumption due to the increase in loss.

  The inlet water temperature of the precooling coil 102 (the feed water temperature from the circulation pump (P4) 103) is 20 ° C. determined by the cooling tower (CT3) 105 for free cooling, and the precooling coil 102 is connected to the computer heat load and the dedicated cooling tower ( CT3) When the ratio is determined to be 105, the air temperature difference between the air inlet temperature 27 ° C. and the outlet temperature 20 ° C. of the air conditioner 101 is 27-7 ° C. × 50% corresponding to the inlet temperature. Determine the precooling coil outlet air temperature.

In each of the above embodiments, the case where the free cooling cooling water circulation path 131 and the precooling water circulation path 130 are connected via the heat exchanger 104 has been described. However, the present invention is not limited to this, and the free cooling cooling tower By using a closed type, the heat exchanger 104 and the circulation pump (P4) 103 may be omitted.
(Third embodiment)
In the air conditioning equipment 1B according to the present embodiment, the room temperature setting is slightly low, and the cooling water supply temperature and the cooling water return temperature of the free cooling cooling water circulation path 131 are the same as the inlet temperature and the outlet temperature of the precooling coil 102, respectively. This is applied when there is no problem with the water quality in the pre-cooling coil 102.

Therefore, in this embodiment, as shown in FIG. 13, the free cooling cooling water circulation path 131 is directly connected to the precooling coil 102 of the air conditioner 101 in the computer room 118.
Since other configurations are the same as those of the first embodiment, the same reference numerals are given and the description thereof is omitted.
According to this embodiment, as in the first embodiment, the cooling tower (CT2) 115 for the second refrigerator and the cooling tower (CT3) for free cooling that are idle due to the low heat load in the winter season or the intermediate period. Since 105 can be cooled in two stages by arranging them in series, the chilled water temperature can be lowered than before.
(Fourth embodiment)
The air-conditioning equipment 1C according to the present embodiment, for example, when performing precise temperature control in a clean room or the like, restricts the humidity control to one place such as an outdoor air conditioner, so that the cooling coil 107 of the circulation system is provided on the air-side surface. In order to obtain a dry coil that does not cause moisture condensation, high temperature cold water (for example, if the indoor temperature control condition is a dew point of 11 ° C., cold water having a cold water supply temperature of 13 ° C. to a cold water return temperature of 18 ° C.) ) And may apply to this.

Therefore, in this embodiment, as shown in FIG. 14, the temperature of the water frozen in the freezer also rises and the improvement of the coefficient of performance is expected as the freezer inlet 18 ° C. and the outlet 13 ° C., and for free cooling in parallel with the freezer A heat exchanger 104 is provided.
In the present embodiment, a pipe 151 connected to the header 113 and a pipe 152 connected to the header 112 are connected to the heat exchanger 104 by a pump 144.

In this embodiment, the air returning from the underfloor space 121 and the cold water in the cold water coil 107 are heat-exchanged in the air conditioner 101, and cold air is blown from the air conditioning chamber 123 to the computer room 118 from the ceiling space 122 of the computer room 118. The air flows from the underfloor space 121 back to the air conditioning chamber 123 where the air conditioner 101 is installed.
Since other configurations are the same as those of the first embodiment, the same reference numerals are given and the description thereof is omitted.

  According to this embodiment, as in the first embodiment, the cooling tower (CT2) 115 for the second refrigerator and the cooling tower (CT3) for free cooling that are idle due to the low heat load in the winter season or the intermediate period. Since 105 can be cooled in two stages by arranging them in series, the chilled water temperature can be lowered than before.

It is explanatory drawing which shows the apparatus structure of the air conditioning equipment which concerns on 1st embodiment of this invention. It is explanatory drawing which shows the control system of the air conditioning equipment of FIG. It is a flowchart of the air conditioning equipment of FIG. It is explanatory drawing which shows the operation | movement of the summer of the air conditioning equipment of FIG. It is explanatory drawing which shows the operation | movement of the intermediate period of the air conditioning equipment of FIG. It is explanatory drawing which shows the operation | movement in winter of the air conditioning equipment of FIG. The cooling tower (CT2) 115 for the second refrigerator and the cooling tower (CT3) 105 for free cooling, which are idle due to the low heat load in the winter or intermediate period, are cooled in series by the air conditioning equipment of FIG. It is a graph explaining a theory. It is a graph which shows the relationship between the external wet-bulb temperature in the cooling tower (CT3) 105 for free cooling, and the entropy of saturated air. The graph which shows the relationship between the external wet-bulb temperature at the time of 23 degreeC of inlet water temperature, and the outlet water temperature in series with the cooling tower (CT3) 105 for free cooling of the same capacity | capacitance, and the cooling tower (CT2) 115 for the 2nd freezer It is. It is a graph which shows the relationship between the outside wet-bulb temperature at the time of the inlet water temperature of 23 degreeC in series with two cooling towers with a large capability of the 2nd cooling tower, and an outlet water temperature. It is a graph which shows the relationship between the external air wet-bulb temperature at the time of 21 degreeC of inlet water temperature and outlet water temperature in series with two cooling towers with the large capability of the 2nd cooling tower. It is explanatory drawing which shows the apparatus structure of the air conditioning equipment which concerns on 2nd embodiment of this invention. It is explanatory drawing which shows the apparatus structure of the air conditioning equipment which concerns on 3rd embodiment of this invention. It is explanatory drawing which shows the apparatus structure of the air conditioning equipment which concerns on 4th embodiment of this invention. It is explanatory drawing which shows the apparatus structure of the conventional air conditioning equipment. 15 is an explanatory diagram showing a control system of the air conditioning equipment. It is a flowchart of the air conditioning equipment of FIG. It is explanatory drawing which shows the operation | movement of the summer of the air conditioning equipment of FIG. It is explanatory drawing which shows the operation | movement of the air conditioning equipment of FIG. 15 in winter.

Explanation of symbols

1, 1A Air conditioning equipment 10 Free cooling switching mechanism 11 First flow path 11a, 12a, 12b Branch point 12 Second flow path 13 First valve (V1)
14 Second valve (V2)
15 Third valve (V3)
16 Fourth valve (V4)
20 Air Conditioner 21 Cooling Coil 22 Outgoing Path 23 Valve 24 Return Path 101 Air Conditioner 102 Precooling Coil 103 Circulation Pump (P4)
104 Heat exchanger 105 Cooling tower for free cooling (CT3)
106 Circulation pump (P3)
107 Cooling coil 108 Refrigerator (R1)
109 Second refrigerator (R2)
110 Circulation pump (CP1)
111 Circulation pump (CP1)
114 Cooling tower (CT1)
115 Cooling tower for the second refrigerator (CT2)
116 Circulation pump (P1)
117 Circulation pump (P2)
118 Computer room 119 Computer 120 Computer room 121 Underfloor space 122 Ceiling space 123 Air conditioning room 124 Controller 125 Valve (VE1)
126 Valve 127 Calorific value calculation controller 130 Precooling water circulation path 131 Free cooling cooling water circulation path 131a Outgoing path 132 of free cooling cooling water circulation path 131 Chilled water circulation path 132a Outbound path 132b of cold water circulation path 132 Return path 133 of cooling water circulation path 132 Cooling Water circulation path 134 Second cooling water circulation path 134a Outward path 134b of second cooling water circulation path 134 Return path 140 of second cooling water circulation path 134 Refrigerator 141 Cooling tower 142 Circulation pumps F1, F2, F3 Flowmeters F1C1, F1C2 , FIC3 Flow controller TIC1, TIC2, TIC3, TIC4, TIC5, TIC6, TIC7 Temperature controller

Claims (13)

An air conditioner provided with a pre-cooling coil and a cooling coil;
An outside air wet bulb thermometer,
A first refrigerator that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer;
A cooling tower for the first refrigerator that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer;
A first cooling water circulation path for providing a liquid pump and communicating the first refrigerator and the cooling tower for the first refrigerator;
At least one or more second refrigerators that start and stop in response to the outside air wet bulb temperature measured by the outside air wet bulb thermometer and the cooling requirement of the cooling coil;
A cooling tower for the second refrigerator that starts and stops in response to a cooling request of the cooling coil and the temperature of the outdoor wet bulb measured by the outdoor wet bulb thermometer;
A second cooling water circulation path for providing a liquid pump and communicating the second refrigerator and the cooling tower for the second refrigerator;
A chilled water circuit that provides a liquid pump and communicates the first refrigerator and the second refrigerator with the cooling coil of the air conditioner;
A cooling tower for free cooling,
A cooling water circuit for free cooling that is provided with a liquid pump and communicates with the cooling tower for free cooling;
A liquid pump, and a cooling water circuit for the precooling coil that communicates with the precooling coil of the air conditioner;
A heat exchanger disposed between the cooling water circuit for free cooling and the cooling water circuit for the precooling coil;
A switching mechanism for free cooling provided between the second cooling water circulation path and the cooling water circulation path for free cooling, and connecting the cooling tower for free cooling and the cooling tower for the second refrigerator in series. When,
A first set value for which free cooling cannot be performed and a second set value for which free cooling can be performed are set in the outside wet bulb temperature measured by the outside air wet bulb thermometer, and switching of the free cooling switching mechanism is performed. A control device for controlling,
The switching mechanism for free cooling is
A first flow path connecting the outgoing path of the cooling water circulation path for free cooling and the return path of the second cooling water circulation path;
A second flow path connecting the outgoing path of the cooling water circulation path for free cooling and the outgoing path of the second cooling water circulation path;
The cooling for free cooling between the branch point on the forward path side of the free cooling cooling water circulation path of the first flow path and the branch point on the forward path side of the free cooling cooling water circulation path of the second flow path. A first valve provided in the water circulation path,
A second valve provided in the first flow path;
A third valve provided in the second flow path;
A fourth valve provided on the second refrigerator side from a branch point on the outgoing path side of the second cooling water circulation path of the second flow path,
The controller is
When the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is equal to or higher than a first set value, the first valve, the second valve, and the third valve are closed, and the fourth valve is opened. Open and perform control to operate the second refrigerator and the cooling tower for the second refrigerator,
When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the first set value and equal to or higher than the second set value, the second refrigerator is stopped, the second valve and the Open the third valve, close the first valve and the fourth valve, and connect the cooling tower for free cooling and the cooling tower for the second refrigerator in series to cool the cooling for free cooling. Control the cooling water in the water circuit in two stages,
When the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer becomes lower than the second set value, the cooling tower for the second refrigerator is stopped, the first valve is opened, and the second valve is opened. The valve and the third valve are closed, and control is performed to cool the cooling water in the free cooling cooling water circulation path one step,
Air conditioning equipment, wherein control is performed to convey cooling water to the heat exchanger via the cooling water circulation path for free cooling. An air conditioner provided with a pre-cooling coil and a cooling coil;
An outside air wet bulb thermometer,
A first refrigerator that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer;
A cooling tower for the first refrigerator that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer;
A first cooling water circulation path for providing a liquid pump and communicating the first refrigerator and the cooling tower for the first refrigerator;
At least one or more second refrigerators that start and stop in response to the outside air wet bulb temperature measured by the outside air wet bulb thermometer and the cooling requirement of the cooling coil;
A cooling tower for the second refrigerator that starts and stops in response to a cooling request of the cooling coil and the temperature of the outdoor wet bulb measured by the outdoor wet bulb thermometer;
A second cooling water circulation path for providing a liquid pump and communicating the second refrigerator and the cooling tower for the second refrigerator;
A chilled water circuit that provides a liquid pump and communicates the first refrigerator and the second refrigerator with the cooling coil of the air conditioner;
A cooling tower for free cooling,
A liquid pump, and a cooling water circulation path for free cooling that communicates the cooling tower for free cooling and the precooling coil of the air conditioner;
A switching mechanism for free cooling provided between the second cooling water circulation path and the cooling water circulation path for free cooling, and connecting the cooling tower for free cooling and the cooling tower for the second refrigerator in series. When,
A first set value for which free cooling cannot be performed and a second set value for which free cooling can be performed are set in the outside wet bulb temperature measured by the outside air wet bulb thermometer, and switching of the free cooling switching mechanism is performed. A control device for controlling,
The switching mechanism for free cooling is
A first flow path connecting the outgoing path of the cooling water circulation path for free cooling and the return path of the second cooling water circulation path;
A second flow path connecting the outgoing path of the cooling water circulation path for free cooling and the outgoing path of the second cooling water circulation path;
The cooling for free cooling between the branch point on the forward path side of the free cooling cooling water circulation path of the first flow path and the branch point on the forward path side of the free cooling cooling water circulation path of the second flow path. A first valve provided in the water circulation path,
A second valve provided in the first flow path;
A third valve provided in the second flow path;
A fourth valve provided on the second refrigerator side from a branch point on the outgoing path side of the second cooling water circulation path of the second flow path,
The controller is
When the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is equal to or higher than a first set value, the first valve, the second valve, and the third valve are closed, and the fourth valve is opened. Open and perform control to operate the second refrigerator and the cooling tower for the second refrigerator,
When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the first set value and equal to or higher than the second set value, the second refrigerator is stopped, the second valve and the Open the third valve, close the first valve and the fourth valve, and connect the cooling tower for free cooling and the cooling tower for the second refrigerator in series to cool the cooling for free cooling. Control the cooling water in the water circuit in two stages,
When the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer becomes lower than the second set value, the cooling tower for the second refrigerator is stopped, the first valve is opened, and the second valve is opened. The valve and the third valve are closed, and control is performed to cool the cooling water in the free cooling cooling water circulation path one step,
Air conditioning equipment, wherein control is performed to convey cooling water to the precooling coil via the cooling water circulation path for free cooling. An air conditioner with a cooling coil;
An outside air wet bulb thermometer,
A first refrigerator that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer;
A cooling tower for the first refrigerator that operates regardless of the outside air wet bulb temperature measured by the outside air wet bulb thermometer;
A first cooling water circulation path for providing a liquid pump and communicating the first refrigerator and the cooling tower for the first refrigerator;
At least one second refrigerator that starts and stops in response to the outside air wet bulb temperature measured by the outside air wet bulb thermometer and the cooling requirement of the cooling coil;
The cooling tower of the second refrigerator that starts and stops in response to the temperature of the outside air wet bulb measured by the outside air wet bulb thermometer and the cooling requirement of the cooling coil;
A second cooling water circulation path for providing a liquid pump and communicating the second refrigerator and the cooling tower for the second refrigerator;
A cooling tower for free cooling,
Providing a liquid pump and a heat exchanger, a cooling water circulation path for free cooling that communicates with the cooling tower for free cooling,
A chilled water circuit that provides a liquid pump and communicates the first refrigerator, the second refrigerator, the heat exchanger, and a cooling coil of the air conditioner;
A switching mechanism for free cooling provided between the second cooling water circulation path and the cooling water circulation path for free cooling, and connecting the cooling tower for free cooling and the cooling tower for the second refrigerator in series. When,
A first set value for which free cooling cannot be performed and a second set value for which free cooling can be performed are set in the outside wet bulb temperature measured by the outside air wet bulb thermometer, and switching of the free cooling switching mechanism is performed. A control device for controlling,
The switching mechanism for free cooling is
A first flow path connecting the outgoing path of the cooling water circulation path for free cooling and the return path of the second cooling water circulation path;
A second flow path connecting the outgoing path of the cooling water circulation path for free cooling and the outgoing path of the second cooling water circulation path;
The cooling for free cooling between the branch point on the forward path side of the free cooling cooling water circulation path of the first flow path and the branch point on the forward path side of the free cooling cooling water circulation path of the second flow path. A first valve provided in the water circulation path,
A second valve provided in the first flow path;
A third valve provided in the second flow path;
A fourth valve provided on the second refrigerator side from a branch point on the outgoing path side of the second cooling water circulation path of the second flow path,
The controller is
When the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer is equal to or higher than a first set value, the first valve, the second valve, and the third valve are closed, and the fourth valve is opened. Open and perform control to operate the second refrigerator and the cooling tower for the second refrigerator,
When the outside air wet bulb temperature measured by the outside air wet bulb thermometer is lower than the first set value and equal to or higher than the second set value, the second refrigerator is stopped, the second valve and the Open the third valve, close the first valve and the fourth valve, and connect the cooling tower for free cooling and the cooling tower for the second refrigerator in series to cool the cooling for free cooling. Control the cooling water in the water circuit in two stages,
When the outdoor wet bulb temperature measured by the outdoor wet bulb thermometer becomes lower than the second set value, the cooling tower for the second refrigerator is stopped, the first valve is opened, and the second valve is opened. The valve and the third valve are closed, and control is performed to cool the cooling water in the cooling water circulation path for free cooling one step,
Air conditioning equipment, wherein control is performed to convey cooling water to the heat exchanger via the cooling water circulation path for free cooling. In the air conditioning equipment according to claim 1 or 3,
The controller is
When the cooling water return temperature supplied to the heat exchanger of the cooling water circulation path for free cooling is T _s and the cooling water return temperature returned from the heat exchanger is T _r ,
The free cooling cooling tower cooling water inlet water temperature (which is equal to the _Tr temperature) ° C. is T _w1 , the free cooling cooling tower cooling water outlet water temperature is T _w2 , and the second flow through the second flow path. Cooling tower cooling water outlet water temperature for the second refrigerator is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air enthalpy at T _w2 ° C is kJ / kgDA is h _w2 , T _w3 ° C Enthalpy of saturated air at kJ / kgDA is h _w3 , proportional constant C ₁ inherent to the cooling tower for free cooling, cooling tower packing height Z ₁ for free cooling, cooling tower water / air ratio for free cooling L / G is N ₁ , proportional constant C ₂ inherent to the cooling tower for the second refrigerator, cooling tower packing height Z ₂ for the second refrigerator, cooling for the second refrigerator Tower water / air ratio L / G is N ₂ The cooling tower for free cooling is obtained by the following logarithmic average formula of the cooling tower characteristics for free cooling and the logarithmic average formula of the cooling tower characteristics for the second refrigerator shown below to obtain the tower characteristics that can be specified and approximated. And T _w2 calculated for each air wet bulb temperature flowing through the cooling tower and T _w3 calculated for each air wet bulb temperature flowing through the cooling tower for the second refrigerator,
Logarithmic average formula of cooling tower characteristics for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
(U / N) ₁ = C ₁ Z ₁ N ₁ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Logarithmic average formula of cooling tower characteristics for the second refrigerator.

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
(U / N) ₂ = C ₂ Z ₂ N ₂ α ⁻¹ , 0.3 ≦ α ≦ 0.5
A graph in which the vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C for free cooling, and the horizontal axis represents the air wet bulb temperature ° C introduced into the free cooling cooling tower, the free cooling _Tw2 calculated for each air wet bulb temperature introduced to the cooling tower and T _w3 calculated for each air wet bulb temperature introduced to the cooling tower for the second refrigerator are respectively plotted to connect plot points. Create two cooling tower outlet water temperature lines,
Air intersection between the second refrigerator of the cooling tower outlet water temperature line and T _s the temperature line of the cooling tower cooling water outlet temperature ℃ for free cooling of the vertical axis drawn parallel to the horizontal axis of the graph Wet bulb temperature ° C is the first set value for outdoor wet bulb temperature,
Air wet-bulb temperature of the intersection of the T _s temperature line of the cooling tower cooling water outlet temperature ℃ for free cooling of the vertical axis drawn parallel to the horizontal axis of the graph and the cooling tower outlet water temperature lines for the free cooling An air conditioner characterized in that ° C is a second set value of the outside air wet bulb temperature. In the air conditioning equipment according to claim 1 or 3,
The controller is
When the cooling water return temperature supplied to the heat exchanger of the cooling water circulation path for free cooling is T _s and the cooling water return temperature returned from the heat exchanger is T _r ,
The free cooling cooling tower cooling water inlet water temperature (which is equal to the _Tr temperature) ° C. is T _w1 , the free cooling cooling tower cooling water outlet water temperature is T _w2 , and the second flow through the second flow path. Cooling tower cooling water outlet water temperature for the second refrigerator is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air enthalpy at T _w2 ° C is kJ / kgDA is h _w2 , T _w3 ° C Enthalpy of saturated air at kJ / kgDA is h _w3 , proportional constant C ₁ inherent to the cooling tower for free cooling, cooling tower packing height Z ₁ for free cooling, cooling tower water / air ratio for free cooling L / G is N ₁ , proportional constant C ₂ inherent to the cooling tower for the second refrigerator, cooling tower packing height Z ₂ for the second refrigerator, cooling for the second refrigerator Tower water / air ratio L / G is N ₂ According to Chebyshev's formula for the cooling tower characteristics for free cooling shown below to obtain tower characteristics that can be specified and approximated, T _w2 calculated for each air wet bulb temperature flowing through the cooling tower for free cooling, _Obtain T _w3 calculated for each air wet bulb temperature flowing through the cooling tower for the second refrigerator,
Chebyshev formula for cooling tower characteristics for free cooling U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W2 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 1 = C 1 Z 1 N 1 α -1, 0.3 ≦ α ≦ 0.5
Chebyshev formula for cooling tower characteristics for second refrigerator U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W3 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 2 = C 2 Z 2 N 2 α -1, 0.3 ≦ α ≦ 0.5
A graph in which the vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C for free cooling, and the horizontal axis represents the air wet bulb temperature ° C introduced into the free cooling cooling tower, the free cooling _Tw2 calculated for each air wet bulb temperature introduced to the cooling tower and T _w3 calculated for each air wet bulb temperature introduced to the cooling tower for the second refrigerator are respectively plotted to connect plot points. Create two cooling tower outlet water temperature lines,
Air intersection between the second refrigerator of the cooling tower outlet water temperature line and T _s the temperature line of the cooling tower cooling water outlet temperature ℃ for free cooling of the vertical axis drawn parallel to the horizontal axis of the graph Wet bulb temperature ° C is the first set value for outdoor wet bulb temperature,
Air wet-bulb temperature of the intersection of the T _s temperature line of the cooling tower cooling water outlet temperature ℃ for free cooling of the vertical axis drawn parallel to the horizontal axis of the graph and the cooling tower outlet water temperature lines for the free cooling An air conditioner characterized in that ° C is a second set value of the outside air wet bulb temperature. In the air conditioning equipment according to claim 2,
The controller is
When the cooling water going temperature supplied to the pre-cooling coil of the cooling circuit for free cooling is T _s and the cooling water return temperature returned from the pre-cooling coil is T _r ,
The free cooling cooling tower cooling water inlet water temperature (which is equal to the _Tr temperature) ° C. is T _w1 , the free cooling cooling tower cooling water outlet water temperature is T _w2 , and the second flow through the second flow path. Cooling tower cooling water outlet water temperature for the second refrigerator is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air enthalpy at T _w2 ° C is kJ / kgDA is h _w2 , T _w3 ° C Enthalpy of saturated air at kJ / kgDA is h _w3 , proportional constant C ₁ inherent to the cooling tower for free cooling, cooling tower packing height Z ₁ for free cooling, cooling tower water / air ratio for free cooling L / G is N ₁ , proportional constant C ₂ inherent to the cooling tower for the second refrigerator, cooling tower packing height Z ₂ for the second refrigerator, cooling for the second refrigerator Tower water / air ratio L / G is N ₂ The cooling tower for free cooling is obtained by the following logarithmic average formula of the cooling tower characteristics for free cooling and the logarithmic average formula of the cooling tower characteristics for the second refrigerator shown below to obtain the tower characteristics that can be specified and approximated. And T _w2 calculated for each air wet bulb temperature flowing through the cooling tower and T _w3 calculated for each air wet bulb temperature flowing through the cooling tower for the second refrigerator,
Logarithmic average formula of cooling tower characteristics for free cooling

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W2 −h ₁
Δh ₂ = h _W1 −h ₂
(U / N) ₁ = C ₁ Z ₁ N ₁ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Logarithmic average formula of cooling tower characteristics for the second refrigerator.

Here, Δh ₁ and Δh ₂ are as follows.
Δh ₁ = h _W3 −h ₁
Δh ₂ = h _W2 −h ₃
(U / N) ₂ = C ₂ Z ₂ N ₂ α ⁻¹ , 0.3 ≦ α ≦ 0.5
Logarithmic average formula of cooling tower characteristics for free cooling The vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C for free cooling, and the horizontal axis represents the temperature of air wet bulb introduced into the free cooling cooling tower ° C In the graph, the _Tw2 calculated for each air wet bulb temperature introduced into the cooling tower for free cooling and the air wet bulb temperature introduced into the cooling tower for the second refrigerator were calculated. Plot _Tw3 and create two cooling tower outlet water temperature lines connecting the plot points.
Air intersection between the second refrigerator of the cooling tower outlet water temperature line and T _s the temperature line of the cooling tower cooling water outlet temperature ℃ for free cooling of the vertical axis drawn parallel to the horizontal axis of the graph Wet bulb temperature ° C is the first set value for outdoor wet bulb temperature,
Air wet-bulb temperature of the intersection of the T _s temperature line of the cooling tower cooling water outlet temperature ℃ for free cooling of the vertical axis drawn parallel to the horizontal axis of the graph and the cooling tower outlet water temperature lines for the free cooling An air conditioner characterized in that ° C is a second set value of the outside air wet bulb temperature. In the air conditioning equipment according to claim 2,
The controller is
When the cooling water going temperature supplied to the pre-cooling coil of the cooling circuit for free cooling is T _s and the cooling water return temperature returned from the pre-cooling coil is T _r ,
The free cooling cooling tower cooling water inlet water temperature (which is equal to the _Tr temperature) ° C. is T _w1 , the free cooling cooling tower cooling water outlet water temperature is T _w2 , and the second flow through the second flow path. Cooling tower cooling water outlet water temperature for the second refrigerator is T _w3 , saturated air enthalpy kJ / kgDA at T _w1 ° C is h _w1 , saturated air enthalpy at T _w2 ° C is kJ / kgDA is h _w2 , T _w3 ° C Enthalpy of saturated air at kJ / kgDA is h _w3 , proportional constant C ₁ inherent to the cooling tower for free cooling, cooling tower packing height Z ₁ for free cooling, cooling tower water / air ratio for free cooling L / G is N ₁ , proportional constant C ₂ inherent to the cooling tower for the second refrigerator, cooling tower packing height Z ₂ for the second refrigerator, cooling for the second refrigerator Tower water / air ratio L / G is N ₂ According to Chebyshev's formula for the cooling tower characteristics for free cooling shown below to obtain tower characteristics that can be specified and approximated, T _w2 calculated for each air wet bulb temperature flowing through the cooling tower for free cooling, _Obtain T _w3 calculated for each air wet bulb temperature flowing through the cooling tower for the second refrigerator,
Chebyshev formula for cooling tower characteristics for free cooling U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W2 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 1 = C 1 Z 1 N 1 α -1, 0.3 ≦ α ≦ 0.5
Chebyshev formula for cooling tower characteristics for second refrigerator U / N = (Cρ × Δt _w / 4) × {(1 / Δh ₁ ) + (1 / Δh ₂ ) + (1 / Δh ₃ )
+ (1 / Δh ₄ )}
Here, Δh _{1 to} Δh ₄ are as follows.
Δh ₁ = t _W3 + 0.1Δt _W in (h _W -h) value Δh ₂ = t _W2 + 0.4Δt _W in (h _W -h) value Δh ₃ = t _W2 -0.4Δt _W in (h _W the value of the values Δh ₄ = t _W2 -0.1Δt _W of _{-h) (h W -h) (} U / N) 2 = C 2 Z 2 N 2 α -1, 0.3 ≦ α ≦ 0.5
A graph in which the vertical axis represents the cooling tower cooling water inlet / outlet water temperature ° C for free cooling, and the horizontal axis represents the air wet bulb temperature ° C introduced into the free cooling cooling tower, the free cooling _Tw2 calculated for each air wet bulb temperature introduced to the cooling tower and T _w3 calculated for each air wet bulb temperature introduced to the cooling tower for the second refrigerator are respectively plotted to connect plot points. Create two cooling tower outlet water temperature lines,
Air intersection between the second refrigerator of the cooling tower outlet water temperature line and T _s the temperature line of the cooling tower cooling water outlet temperature ℃ for free cooling of the vertical axis drawn parallel to the horizontal axis of the graph Wet bulb temperature ° C is the first set value for outdoor wet bulb temperature,
Air wet-bulb temperature of the intersection of the T _s temperature line of the cooling tower cooling water outlet temperature ℃ for free cooling of the vertical axis drawn parallel to the horizontal axis of the graph and the cooling tower outlet water temperature lines for the free cooling An air conditioner characterized in that ° C is a second set value of the outside air wet bulb temperature. In the air conditioning equipment according to any one of claims 4 to 7,
An air-conditioning facility comprising a cooling tower for a second refrigerator in which C ₂ = C ₁ , Z ₂ = Z ₁ , and N ₂ = N ₁ . In the air conditioning equipment according to any one of claims 4 to 7,
An air conditioner comprising a cooling tower for a second refrigerator, wherein Z ₂ > Z ₁ and N ₂ <N ₁ . In the air conditioning equipment according to any one of claims 1 to 9,
The free cooling cooling water circulation path is provided with the liquid pump in the forward path, and a first flow rate between the liquid pump and the branch point of the free cooling cooling water circulation path on the forward path side. Air conditioning equipment, characterized by a meter and a second flow meter on the return path. In the air conditioning equipment according to any one of claims 1 to 9,
An air conditioner further comprising an air conditioner provided with a cooling coil connected to the cooling coil. In the air conditioning equipment according to claim 4 or 5,
The apparatus further includes an input device for setting a predetermined value to the cooling water return temperature T _s supplied to the heat exchanger of the free cooling cooling water circuit and the cooling water return temperature returned from the heat exchanger to T _r. ,
The control device stores a calculation unit that calculates and calculates a first set value of the outdoor wet bulb temperature and a second set value of the outdoor wet bulb temperature, and calculates a predetermined value input by the input device As a result, control of the switching mechanism for free cooling, the cooling tower for free cooling, the second refrigerator, and the cooling tower for the second refrigerator is performed. In the air conditioning equipment according to claim 6 or 7,
An input device for setting a predetermined value to the cooling water return temperature T _s supplied to the pre-cooling coil of the cooling water circuit for free cooling and the cooling water return temperature returned from the thermal pre-cooling coil to _Tr ;
The control device stores a calculation unit that calculates and calculates a first set value of the outdoor wet bulb temperature and a second set value of the outdoor wet bulb temperature, and calculates a predetermined value input by the input device As a result, control of the free cooling switching mechanism, the free cooling cooling tower, the second refrigerator, and the cooling tower for the second refrigerator is performed.

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