JP2016017674A - Outdoor atmosphere utilizing air conditioning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the necessity to have dehumidifying function and humidifying function directly to an outdoor air cooling device and to enable a further energy saving to be attained.SOLUTION: A direct outdoor atmosphere utilizing air conditioning system 71 cools an electronic device with outdoor atmosphere by making the outdoor atmosphere pass a space to be cooled. An inside air circulation type air conditioning system 72 does not flow-in the outdoor atmosphere into the space to be cooled, but cools return air (warm air) flowed back from the space to be cooled to generate cold air, supplies the cold air to the space to be cooled and then cools the electronic device. A control device 60 operates either the direct outdoor atmosphere utilizing air conditioning system 71 or the inside air circulation type air conditioning system 72 on the basis of results of measurement of a dry bulb temperature or a dew point temperature of the outdoor atmosphere.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an air conditioning system that uses outside air.

  Conventionally, for example, many electronic devices such as server devices are installed in a data center, a server room of a company, or the like. In such a server room, the room temperature rises due to the heat generated by a large number of electronic devices, and the server may run away or break down due to this room temperature rise. For this reason, an air conditioning system that keeps the temperature of the entire room constant is adopted for the server room. In addition, such an air conditioning system is almost always operated, and is operated even in winter.

  In a conventional air conditioning system for a cooling target space such as a server room, in order to stabilize the room temperature of the server room, low-temperature air (cold air) blown from the air conditioner and supplied into the server room is The server device and the like flow while contacting the server device and the like to cool the server device and the like. The air (warm air) heated by the heat of the server is returned from the server room into the air conditioner, cooled by the air conditioner, blown out as the cold air, and supplied again to the server room. The circulation method is taken.

  The system for cooling the server room or the like as described above operates even in winter, that is, operates even when the outside air temperature is low. Therefore, an air conditioning system capable of obtaining an energy saving effect using outside air has been proposed.

  For example, the invention of Patent Document 1 provides an effective and appropriate air-conditioning facility that is capable of high-level temperature control for a server room, and that can also perform cooling operation with all outside air and can provide a sufficient energy saving effect. .

  In the invention of Patent Document 1, the air conditioner 3 and the exhaust fan 7 capable of controlling the temperature in accordance with the cooling load in the server room 1 are configured to allow all-outside air cooling operation for the server room. A first path for directly introducing outside air is connected to the outside air shaft 6 via the damper mechanism 12 in order to introduce outside air. Furthermore, the second path for introducing outside air through a cool tube (for example, seismic isolation pit 2) after lowering the temperature by exchanging heat with the ground heat is switchably connected to the first path by a damper mechanism. To do.

In addition, the present applicant has proposed the inventions described in Patent Documents 2, 3, 4 and the like, for example.
In invention of patent document 2, it is the integrated air-conditioning system 50 formed by connecting the internal air unit 60 and the external air unit 70 on both sides of the wall 1, Comprising: A structure (liquid-gas heat exchanger 61b, 71b, piping 51, etc.) and a configuration as a general air conditioner (evaporator 61a, expansion valve 54, compressor 55, condenser 71b, etc.) are proposed.

  In the invention of Patent Document 3, the inside air unit 90 includes a laminated body 91 including a blower (fan) 91a, a condenser 91b, a liquid-gas heat exchanger 91c, an evaporator 91d, and the like. In a normal system, a configuration is proposed in which a condenser that is installed outside a building and allows outside air to pass therethrough is installed inside the building and allows inside air to pass through. With this configuration, when the outside air temperature is higher than the inside air temperature, the cooling effect of the refrigerant in the condenser is high.

  Moreover, in invention of patent document 4, it is the 1st mode which performs independent operation of an indirect external air cooler, 2nd mode which performs independent operation of a general air conditioner, and the mode which performs combined operation of a general air conditioner and an indirect external air cooler. Any mode of the third mode is set as the current operation mode, and the operation control of the air conditioner and / or the indirect outside air cooler is performed in the current operation mode.

JP 2013-245913 A Table 2012/073746 (WO2012 / 073746) Table 2012/090850 (WO2012 / 090850) WO2013 / 125650

  Here, for example, in the control method described in Patent Document 4, indirect outside air cooling single operation mode, indirect outside air cooling and freezer cooling combined operation mode, freezer cooling single operation mode, etc. The various modes are switched. In particular, in an environment where the outside air temperature is relatively low, a remarkable energy saving effect can be obtained by performing independent operation of indirect outside air cooling.

  By the way, generally, in an air conditioner using outside air, a method (indirect outside air cooling) in which outside air does not flow into the cooling target space as in Patent Documents 2, 3, and 4, and outside air flows into the cooling target space. A method (direct outside air cooling) is known. And it is known that direct outside air cooling has a higher energy saving effect than indirect outside air cooling.

  However, particularly when the space to be cooled is a server room or the like, the humidity of the outside air, the dust contained in the outside air, or the like becomes a problem. For example, when the humidity of the outside air is too low, there arises a problem that static electricity is easily generated. Also, normally, when the outside air humidity is too high, it becomes a problem for electronic devices such as server devices. For this reason, for example, it is necessary to provide a dehumidifying function or a humidifying function directly in the outside air cooling device, which complicates the configuration and increases the cost. Furthermore, naturally, energy (electric power) for dehumidification and humidification is required, which causes a problem in terms of energy saving.

  An object of the present invention is to provide an outside air-conditioning system that uses both direct outside air cooling and indirect outside air cooling, and by using the outside heat more effectively, an outside air-conditioning system that can further save energy, etc. Is to provide.

  The outside air-conditioning air conditioning system of the present example has a direct outside air-conditioning system that cools the electronic device with the outside air by allowing the outside air to pass through the cooling target space having the electronic device, and does not allow the outside air to flow into the cooling target space. And cooling the return air from the space to be cooled to cool air, supplying the cold air to the space to be cooled to cool the electronic device, and the direct outside air-conditioning air conditioning system and the inside air circulation. And a control device that operates any one of the air conditioning systems.

  The control device includes an operation mode determination / control unit that determines whether to operate the direct outside air-conditioning air conditioning system or the inside air circulation type air conditioning system based on the temperature of the outside air.

  According to the outside air use air conditioning system and the like of the present invention, it is possible to achieve further energy saving by using an outside air use air conditioning system that uses both direct outside air cooling and indirect outside air cooling together, and more effectively using the cold air of outside air. . Furthermore, for example, further energy saving can be achieved by eliminating the need to provide a dehumidifying function or a humidifying function directly to the outside air cooling device.

It is a whole block diagram (sectional drawing) of the external air utilization air-conditioning system of this example. It is a whole block diagram (plan view) of the outside air utilization air-conditioning system of this example. (A), (b) is a figure for demonstrating the operation mode A. FIG. (A), (b) is a figure for demonstrating the operation mode B. FIG. (A), (b) is a figure for demonstrating the operation mode C. FIG. (A)-(c) shows the conditions and driving | running states which are set as each operation mode, (d) is a figure which shows the conditions set as each driving mode on an air diagram. It is a flowchart figure (the 1) of a mode determination process. It is a flowchart figure (2) of mode determination processing. It is a structural example (the 1) of an indirect external air utilization type | formula air conditioner. It is a structural example (the 2) of an indirect external air utilization type | formula air conditioner. It is a functional block diagram of this system.

Embodiments of the present invention will be described below with reference to the drawings.
1 and 2 are overall configuration diagrams of the outside-air-use air conditioning system of this example.
1 is a cross-sectional view, and FIG. 2 is a plan view.

Hereinafter, description will be made mainly with reference to FIG.
As shown in FIG. 1, here, an example is shown in which an outside air-use air conditioning system of this example is constructed in a 5-story data center.

  This system basically includes an air conditioner 10 using direct outside air and an air conditioner 10 using indirect outside air. The indirect outside air utilization type air conditioner includes an indirect outside air utilization type air conditioner (indoor unit) 20 and an indirect outside air utilization type air conditioner (outdoor unit) 30 shown in the figure. In the following description, it may be collectively referred to as an indirect outside air utilization type air conditioner 20 or the like.

  In the figure, the indirect outside air type air conditioner (outdoor unit) 30 is shown only with respect to the indirect outside air type air conditioner 20 shown in the upper right of the figure, but all other indirect outside air type air conditioners 20 are also illustrated. Are omitted, and an indirect outside air-use type air conditioner (outdoor unit) 30 is connected. Note that the indirect outside air use type air conditioner (indoor unit) 20 and the indirect outside air use type air conditioner (outdoor unit) 30 are connected via, for example, a brine pipe 31 shown in the figure.

Although omitted here, the indirect outside air-utilizing air conditioner (indoor unit) 20 may be further supplied with cold water from, for example, the cold water system of FIG. 9 described later.
Further, the indirect outside air utilization type air conditioner 20 or the like may be configured as described in, for example, the above Patent Documents 2, 3, 4 and the like, for example, “Configuration as an Indirect Outside Air Cooler” and “General It may have a configuration as an air conditioner. However, the present invention is not limited to this example. For example, the above-described “configuration as an indirect outside air cooler” and a configuration using a chilled water system described later may be used. In any case, a detailed configuration example of the indirect outside air use type air conditioner 20 will be described later.

A configuration example of FIG. 1 will be described.
First, on the first floor, an outside air intake gallery 1 is provided on a building wall or the like, and an outside air type air conditioner 10 is directly installed. The direct outside air utilization type air conditioner 10 includes a filter 11, a humidifier 12, a cooling coil 13, a fan 14, a damper 15, and the like. However, as will be described later, the present invention is not limited to this example.

  The inflow of outside air into the building is performed through the outside air intake gallery 1. This outside air flows directly into the outside air utilization type air conditioner 10, passes through the filter 11, the humidifier 12, the cooling coil 13, etc., and is sent out to the air supply shaft 5 by the fan 14. However, this is a story when the illustrated damper 15 is in the “open” state, and outside air does not flow into the air supply shaft 5 when the damper 15 is in the “closed” state.

  The humidifier 12 is not always necessary. This is because, as will be described later, in this method, when the humidity (dew point temperature) of the outside air becomes less than a predetermined lower limit value, it can be dealt with by stopping the introduction of the outside air. Further, the cooling coil 13 is not necessarily required. Further, according to this method, it is not necessary to provide a dehumidifier directly on the outside air type air conditioner 10. Further, even if the humidifier 12 is present, it is not necessary to make it function.

  Here, the space above the second floor of the building is roughly divided into each server room 4 that is a space to be cooled, the air supply shaft 5, the exhaust shaft 6, and the like. On the second floor, there is a room in which a UPS (Uninterruptible Power Supply) 2 and a battery 3 are installed instead of the server room 4, but this is not particularly described. However, this room may also be a space to be cooled, and the UPS 2 and the battery 3 may be cooled in the same manner as the server room 4.

  Further, since the configurations of the third floor, the fourth floor, and the fifth floor are the same, only the fifth floor will be described as a representative. Further, as shown in the figure, there are a plurality of server rooms 4a, server rooms 4b,..., And server rooms 4e. . The same applies to the air supply shaft 5, the exhaust shaft 6, the return damper 8, and the exhaust damper 9 described later.

  In addition, an indirect outside air type air conditioner (indoor unit) 20 is installed in the air supply shaft 5 for each floor. However, the cold air outlet of the indirect outside air-use type air conditioner (indoor unit) 20 is configured to exist in the server room 4. The air supply shaft 5 and the exhaust shaft 6 are basically spaces adjacent to the server room 4.

  The indirect outside air type air conditioner (indoor unit) 20 sends the supply air SA to the server room 4 from a cold air outlet (not shown). The supply air SA is basically cold air. This cold air may be the outside air directly supplied from the outside air utilization type air conditioner 10, or the return air RA from the server room 4 may be used as an indirect outside air utilization type. The air-conditioner (indoor unit) 20 may be cooled. In the server room 4, the cool air becomes warm air RA by cooling the server device 41 and the like. In this method, the warm air RA may be discharged from the exhaust shaft 6 to the outside of the building, or may be returned to the indirect outside air utilization type air conditioner (indoor unit) 20 through the air supply shaft 5. Here, in particular, the warm air RA that is returned to the indirect outside air-use type air conditioner (indoor unit) 20 may be referred to as return air RA.

  FIG. 2 is a plan view of the third, fourth and fifth floors. Although not described in detail with respect to FIG. 2, each server room 4 has an air supply shaft 5 and an exhaust shaft 6 on both sides thereof. In the air supply shaft 5, for example, an indirect outside air type air conditioner (indoor unit) 20 is installed as illustrated. Here, the outdoor unit 30 is omitted. In addition, as shown in FIG. 2, in each server room 4, for example, a large number of server devices 41 are installed in a row as shown. Note that the rectangle denoted by reference numeral 41 in the figure may be a rack in which the server device is mounted instead of the server device itself.

  The operation control of the outside air-use air conditioning system is roughly divided into a state in which the outside air-use type air conditioner 10 is directly functioned and a state in which it is not functioned. Basically, in the state in which the direct outside air utilization type air conditioner 10 is functioned, the indirect outside air utilization type air conditioner 20 or the like is not functioned. However, in order to supply the outside air of the supply shaft 5 to the server room 4, indirect outside air utilization is used. The fan of the type air conditioner 20 is operated. On the other hand, in a state where the direct outside air utilization type air conditioner 10 is not functioned, the indirect outside air utilization type air conditioner 20 or the like is caused to function.

  In a state where the direct outside air use type air conditioner 10 is functioned, the outside air directly supplied from the outside air use type air conditioner 10 into the supply shaft 5 as described above causes the indirect outside air use type air conditioner (indoor unit) 20. It flows into the server room 4 through. The outside air passes through the server room 4 and cools the server device 41 to become warm air RA and is discharged to the exhaust shaft 6. Then, the air is exhausted outside the building through the exhaust shaft 6. Hereinafter, this operation will be described in more detail with reference to FIG.

  In the following description, it is assumed that the direct outdoor air-conditioning air conditioner 10 may be simplified and described as the direct air conditioner 10. Similarly, when the indirect outside air utilization type air conditioner 20 or the like is described as an indirect air conditioner 20 or the like, or when the indoor unit or the outdoor unit is described as an indirect air conditioner (indoor unit) 20 or an indirect air conditioner (outdoor unit) 30. It shall be.

FIG. 3 is a diagram for explaining an operation mode (mode A) in which the outdoor-air-conditioning air conditioner 10 functions directly.
FIG. 3 (a) shows the conditions for mode A and the operating conditions of the air conditioners 10, 20 and the like in mode A. Among these, the conditions for mode A will be described later. As shown in the figure, the air conditioner 10 is in the operating state, and the indirect air conditioner 20 and the like are in the operating state with only the fan.

In mode A, the open / close state of each damper is controlled as shown in FIG. 3 (b), whereby the air flow is indicated by arrows in FIG. 3 (b).
That is, as shown in FIG. 3 (b), the damper 15 is set in the “open” state, whereby the outside air is directly supplied from the air conditioner 10 into the air supply shaft 5. This outside air is sucked into each indirect air conditioner (indoor unit) 20 within the air supply shaft 5 as indicated by an arrow, and is supplied as it is into the server room 4. Then, the outside air passes through the server room 4 and cools the server device 41 to become warm air RA and goes to the upper space in the server room 4.

  Here, on the upper space side of the server room 4, the return damper 8 is provided between the supply shaft 5 and the exhaust damper 9 is provided between the exhaust shaft 6. . In the mode A, the overall controller 100 controls the return damper 8 to be “closed” and the exhaust damper 9 to be “open”. Thus, the warm air RA is exhausted to the exhaust shaft 6 without returning to the air supply shaft 5. Then, it is discharged out of the building via the exhaust shaft 6.

  As described above, in the mode A, the outside air that has flowed into the building from the outside air intake gallery 1 is directly the air conditioner 10 → the air supply shaft 5 → the indirect air conditioning indoor unit 20 → the server room, as indicated by the arrow in the figure. 4 → exhaust damper 9 → exhaust shaft 6 in this order, and finally exhausted from the exhaust shaft 6 to the outside of the building.

  The opening / closing control of each damper, the mode determination process, and the operation / stop control of the direct air conditioner 10 and the indirect air conditioner 20 are executed by, for example, the overall controller 100 shown in FIG. The overall controller 100 includes an arithmetic processor such as a CPU / MPU (not shown) and a storage unit such as a memory. A predetermined application program is stored in the storage unit in advance. When the arithmetic processor executes this application program, the opening / closing control of each damper, the mode determination process, the operation / stop control of the direct air conditioner 10 and the indirect air conditioner 20, and the like are realized. The mode determination process is, for example, a process shown in FIGS.

  Although not shown in FIG. 1, a thermometer for measuring the dry bulb temperature of the outside air and a dew point thermometer for measuring the dew point temperature of the outside air are installed. The installation location is, for example, near the filter 11 of the direct air conditioner 10 or the outside air intake gallery 1, but is not limited to this example. Further, a thermometer for measuring the dry bulb temperature of the return air RA is provided, for example, in the vicinity of the return damper 8 of each supply shaft 5. The overall controller 100 is connected to each thermometer, dew point thermometer, etc. (not shown) via a communication line (not shown), and can collect each measured value in real time. Furthermore, the overall controller 100 is also connected to each control object (dampers 8, 9, 15 and the direct air conditioner 10 or indirect air conditioner 20) via a communication line (not shown), and sends a control signal via the communication line. These control objects are controlled.

  In the operation mode in which the air conditioner 10 does not function directly, that is, in the mode B and mode C described later, the open / close state of each damper and the air flow caused thereby are as shown in FIG. 4 (b) and FIG. 5 (b). Become.

  FIG. 4B shows the open / close state of each damper in mode B, which will be described later, and the air flow caused thereby is indicated by arrows. Since this is the same as in FIG. 5B, only FIG. 4B will be described below.

  As shown in FIG. 4B, in the mode B, the damper 15 is in the “closed” state, and the exhaust damper 9 is also in the “closed” state. As a result, the supply shaft 5 and the server room 4 are cut off from the outside air environment, and the outside air does not flow into the server room 4. Then, by setting the return damper 8 in the “open” state, the warm air RA in the server room 4 flows into the air supply shaft 5 as the return air RA. The return air RA is sucked into the indirect air conditioner (indoor unit) 20, cooled in the indirect air conditioner (indoor unit) 20, becomes cold air, and is supplied to the server room 4 as the supply air SA. . The supply air SA (cold air) cools the server device 41 in the server room 4 to become warm air RA, and flows into the supply shaft 5 again as return air RA through the return damper 8.

  In this manner, the air (inside air) in the building circulates between the server room 4 and the air supply shaft 5 while alternately repeating the warm air state and the cold air state. That is, in this state, it is not affected by the humidity of the outside air, dust contained in the outside air, or the like.

  Here, for example, as described above, the indirect air conditioner 20 and the like may include the configuration of Patent Document 2, that is, the “indirect outside air cooler” and the “general air conditioner”. In this example, the mode B may be regarded as a mode in which both the “indirect outside air cooler” and the “general air conditioner” are operated in combination. Mode C may be regarded as a single operation mode of the “general air conditioner”.

  The “general air conditioner” is an air conditioner that basically functions as a cooling function even when the outside air temperature is high, and can generate cool air having an arbitrary set temperature. It is an air conditioner using a general compression refrigeration cycle (vapor compression refrigeration cycle or the like) of “evaporator → compressor → condenser → expansion valve → evaporator”. However, the present invention is not limited to this example. As another example of the “general air conditioner”, for example, a cold water type air conditioner having a chiller described later is known. In any case, the “general air conditioner” itself may be an existing general air conditioner and will not be described in detail.

  Note that the specific operation control method for mode B and mode C is, for example, mode B, mode C, and mode D described in Patent Document 4 (hereinafter, in order to distinguish from the mode of this example, Patent Document 4 Each mode described in the above may be substantially the same as the operation control method of “mode B ′, mode C ′, mode D ′, etc. attached with“ ””, and is not particularly described here. Shall.

  As described above, the operation control method itself in each mode of FIGS. 4 and 5 may be substantially the same as the conventional method of Patent Document 4 or the like, but in this example, the opening / closing control of the dampers 8, 9, and 15 is further performed. Is required.

  Moreover, the structure of FIG. 1 is an example, and is not limited to this example. For example, you may make it provide the duct etc. which can supply the external air sent directly from the air conditioner 10 to each server room 4 directly. In this case, in the mode A, it is not necessary to operate the fan of the indirect air conditioner (indoor unit) 20. In this case, the opening / closing control of the dampers 8, 9, and 15 may be the same as that described with reference to FIG.

  Here, as described above, it is generally known that direct outside air cooling has a higher energy saving effect than indirect outside air cooling. Thus, in this example, the operation is performed in the mode A as long as the external environment (outside air temperature, humidity, etc.) is an environment in which the air conditioner 10 can function directly. And if it becomes the environment where the air conditioner 10 cannot function directly, it will switch to mode B. Further, when the environment becomes such that the “indirect outside air cooler” cannot function, the mode is switched to mode C.

  Here, conditions (operation mode determination conditions) for determining whether the current operation mode is the mode A, B, or C are shown in FIGS. 3 (a), 4 (a), and 5 (a). However, these are collectively shown in FIGS. 6 (a), 6 (b), and 6 (c). Further, FIG. 6D shows a region determined as mode A, a region determined as mode B, and a region determined as mode C on the air diagram.

  In the air diagram of FIG. 6D, the horizontal axis is the dry bulb temperature (° C.) and the vertical axis is the absolute humidity, and here, the dry bulb temperature (° C.) and the absolute humidity of the outside air are applied. As is well known, the dew point temperature of the outside air is determined according to the dry bulb temperature (° C.) and the absolute humidity. However, in practice, the dew point temperature may be measured with a dew point thermometer. A thermometer and a dew point thermometer for measuring the dry bulb temperature (° C.) and dew point temperature of the outside air are provided, for example, directly behind the filter 11 (outside air inlet) in the air conditioner 10. Not exclusively. In this example, it is assumed that humidification and dehumidification are not performed directly in the air conditioner 10.

Hereinafter, the mode determination method will be described with reference to FIG.
In the following description, when the temperature is simply referred to, it basically means the dry bulb temperature, and the dew point temperature is always described as the dew point temperature.

  In the mode determination process of this example, real-time measurement data such as the dry-bulb temperature (° C.), dew point temperature, server exhaust temperature (measurement temperature of warm air RA) of the outside air, and preset setting values are used. . This set value is, for example, the server intake air condition range shown in FIG. That is, the cool air (supply air SA) supplied to the server room 4 may be regulated such that the temperature and humidity (dew point temperature) are within a predetermined range. In the example shown in FIG. 6D, regarding the temperature, the upper limit is 27 ° C. and the lower limit is 18 ° C. The dew point temperature is required to be in the range of 5.5 (° C. DP) to 15 (° C. DP). However, in this example, the temperature may be less than the lower limit (18 ° C.).

  First, as shown in FIG. 6C, when the outside air temperature is higher than the server exhaust temperature (measured temperature of the warm air RA), the mode C is set. Since the server exhaust temperature is not a set value as described above, it can vary, but here it is assumed that it was 34 ° C. Accordingly, as shown in FIG. 6D, when the outside air temperature is 34 ° C. or higher, the mode C is set regardless of the humidity.

In this description, the outside air temperature basically means the dry bulb temperature of the outside air, and the “dew point temperature” basically means the dew point temperature of the outside air.
When the outside air temperature is lower than the server exhaust temperature (34 ° C. in this example), mode A is basically set when the outside air temperature and the dew point temperature are within the server intake air condition range. However, in this example, the outside air temperature may be less than this condition range. Thus, when the outside air temperature and the dew point temperature are within the range indicated by the oblique lines in FIG. 6D (the range including the server intake air condition range), the mode A is set.

  In other words, as shown in FIG. 6A, “the outside air temperature is less than the upper limit of the dry bulb temperature in the server intake air condition range (27 ° C. in the example of FIG. 6D), and the outside air When the dew point temperature is within the range related to the dew point temperature in the server intake air condition range (5.5 ° C. DP to 15 ° C. DP in the example of FIG. 6D), the mode A is set.

  On the other hand, when the outside air temperature is lower than the server exhaust temperature (34 ° C. in this example) and is not determined as mode A, it is determined as mode B. That is, in FIG. 6D, in the region where the outside air temperature is less than 34 ° C., the mode B is determined when the combination (intersection) of the outside air temperature and the dew point temperature is outside the region indicated by the oblique lines.

In addition, the determination method of the mode A and the mode B is, in other words, as follows in the example of FIG.
-When the outside air temperature (dry bulb temperature) is 27 ° C. or higher and lower than 34 ° C., mode B is set.
When the outside air temperature (dry bulb temperature) is less than 27 ° C., mode A is set if the dew point temperature is within the range of 5.5 ° C. DP to 15 ° C. DP, and mode B is set otherwise.

FIG. 7 shows a flowchart of the mode determination process.
The process of FIG. 7 is periodically executed by the overall controller 100, for example.
Although not shown in the figure, at the start of processing, the overall controller 100 first determines the measured value of the temperature of the warm air (returned air) RA (34 ° C. in the above example), the dry bulb temperature and the dew point temperature of the outside air. Get the measured value.

  First, it is determined whether or not the outside air temperature (dry bulb temperature) is equal to or higher than the temperature of the warm air RA (step S11). When “the temperature of the outside air ≧ RA” (step S11, YES), it is determined as mode C and control for operating as mode C (opening / closing control of the dampers 8, 9, 15 and the like). Is executed (step S14).

  On the other hand, when the outside air temperature is lower than the temperature of the warm air RA (step S11, NO), it is subsequently determined whether or not the outside air temperature is equal to or higher than the set value PA (step S12). Here, PA is an upper limit value of the dry bulb temperature in the above-described server intake air condition range (server intake air upper limit dry bulb temperature; in the above example, 27 ° C.).

  When “outside air temperature ≧ PA”, in other words, when the outside air temperature is equal to or higher than PA and lower than RA (step S12, YES), it is determined as mode B and control for operating as mode B is performed. Is executed (step S15).

  When the outside air temperature is lower than PA, it is determined whether to set the mode B or the mode A based on the dew point temperature of the outside air. That is, if the dew point temperature of the outside air is within a predetermined range set in advance (step S13, YES), it is determined as mode A and control for operating as mode A is executed (step S17). The predetermined range is, for example, a range related to the dew point temperature in the server intake air condition range (5.5 ° C. DP to 15 ° C. DP in the example of FIG. 6D), but is not limited to this example. Absent.

  On the other hand, when the dew point temperature of the outside air is outside the above predetermined range (in the example of FIG. 6D, when it is less than 5.5 ° C. DP or exceeds 15 ° C. DP) (step S13, NO ), Mode B is determined, and control for operating as mode B is executed (step S16).

The process of FIG. 7 shows an example of the mode determination process, and is not limited to this example. For example, the mode determination process may be the process shown in FIG.
Hereinafter, the process of FIG. 8 will be described.

FIG. 8 is a flowchart (part 2) of the mode determination process.
8 is also periodically executed by, for example, the entire controller 100. Further, at the start of the process, first, the measurement value of the temperature of the warm air RA and the measurement values of the dry bulb temperature and the dew point temperature of the outside air are acquired as in FIG. The difference from FIG. 7 is a set value used for comparison with these measured values, and an SA temperature set value and a dew point temperature set value are used. The SA temperature set value is a set temperature of the indirect air conditioner 20, in other words, a set temperature of cool air (supply air SA) supplied to the server room 4. During operation in mode B or mode C, control is performed so that “temperature of supply air SA = (≈) SA temperature set value”. This control itself is an existing general control and will not be described here.

  Further, in the example of FIG. 8, regarding the dew point temperature of the outside air, the threshold value condition is used instead of the range condition as shown in FIG. 7, and this is the dew point temperature setting value. That is, not the determination method of whether it is in a range, but the determination method of whether it is more than a threshold value is used. Here, the dew point temperature setting value may be set arbitrarily, but as an example, it is a threshold value for determining whether or not “a state where static electricity can occur because the humidity of the outside air is too low”. You can think. Accordingly, as an example, the dew point temperature set value is the lower limit value of the dew point temperature in the server intake air condition range (5.5 ° C. DP in the example of FIG. 6D), but is not limited to this example.

  In the process of FIG. 8, the determination process in step S21 and the process in step S24 when this determination is YES are the same as the processes in steps S11 and S14, and the description thereof is omitted here.

  If the determination in step S21 is NO, it is subsequently determined whether the dry bulb temperature of the outside air is equal to or higher than the “SA temperature set value” (step S22). When the outside air temperature is equal to or higher than the “SA temperature set value” (step S22, YES), it is determined as mode B and control for operating as mode B is executed (step S25).

  On the other hand, when the outside air temperature is lower than the “SA temperature set value” (step S22, NO), it is determined whether the mode B or the mode A is set based on the measured dew point temperature. That is, when the dew point temperature of the outside air is lower than the above dew point temperature set value (step S23, YES), it is determined as mode B and control for operating as mode B is executed (step S26). On the other hand, when the dew point temperature of the outside air is equal to or higher than the dew point temperature set value (step S23, NO), it is determined as mode A and control for operating as mode A is executed (step S27).

Here, step S12 and step S22 will be described.
First, the upper limit value of the intake air temperature of the server device 41 (suction temperature upper limit value) is normally defined. Based on this, in consideration of the safe operation of the server device 41, the set value of the air temperature of the air conditioner (the “SA temperature set value”) is generally 3 to 5 ° C. higher than the suction temperature upper limit value. The temperature is set to a low level.

  From the above, for example, if the set temperature cannot be maintained due to the outside air temperature exceeding the “SA temperature set value” during operation in mode A, for example, the outside air introduction is stopped and the indirect outside air type air conditioner 20 is stopped. Switch to such operation. However, as described above, the “SA temperature set value” is set to a temperature lower than the suction temperature upper limit value. Therefore, it is conceivable to continue the operation in mode A until the outside air temperature reaches the suction temperature upper limit value. Comparing the two, the former can be operated more safely, but the latter has a higher energy saving effect.

  From the above, the process of step S22 corresponds to the former case, and the process of step S12 corresponds to the latter case. However, the present invention is not limited to these examples. For example, when an arbitrary temperature within the range between the suction temperature upper limit value and the “SA temperature set value” is set as a threshold value and the outside air temperature is equal to or higher than the threshold value, The direct air conditioner 10 may be stopped and the indirect air conditioner 20 may be operated.

  Further, the humidity of the outside air is not limited to the above example. For example, step S23 may be executed instead of step S13 in the process of FIG. 7, or step S13 is executed instead of step S23 in the process of FIG. May be.

  Here, normally, regarding the intake air of the server device 41, there are upper and lower limits on both temperature and humidity. One example thereof is the server intake air condition range shown in FIG. The process of step S13 may be regarded as a process for determining whether or not the humidity (dew point temperature) of the outside air satisfies the upper and lower limit constraints on the humidity. However, the process is not limited to this example, and may be a process for determining whether the humidity (dew point temperature) of the outside air satisfies, for example, any one of the upper and lower limit constraints, and an example thereof is the step S23. It is processing. This example is processing for determining whether or not the lower limit constraint is satisfied, but is not limited to this example.

  Further, as described above and as shown in FIG. 6 (d), regarding the server intake air condition range, a lower limit for temperature (18 ° C. in the illustrated example) is also defined, but as shown in FIG. In the example, the lower limit is not used for determination. This is because when the outside air temperature is low, the temperature can be increased by mixing a part of the warm air RA in the server room 4. As a specific method, the opening degree of the damper 8, the damper 9, and the damper 15 is adjusted so that the cold air (supply air SA) temperature supplied to the server room 4 is adjusted to be within a predetermined range, and the server room 4 The amount of outside air supplied to the server room 4 and the amount of exhaust discharged from the server room 4 are balanced. Instead of adjusting the opening degree of the damper 15, the rotational speed of the fan of the air conditioner 10 may be directly adjusted. Since this control itself is an existing general control, it is not described here, but is not limited to this example.

  Based on the above, this method is basically based on “when the measured dry-bulb temperature and dew point temperature of the outside air satisfy a predetermined condition as air to be supplied to the cooling target space (server room 4 etc.)”. Directly puts the outdoor air-conditioning type air conditioner 10 into an operating state. An example of the predetermined condition is a determination criterion relating to the above-described steps S12, S13, S22, and S23.

  Basically, the indirect outside air type air conditioner 20 or the like is stopped during operation of the direct outside air type air conditioner 10, and conversely, the direct outside air type air conditioner 20 or the like is stopped during operation. The air conditioner 10 is stopped.

  In addition, from the above, for example, in this method, it is not necessary to perform humidification or dehumidification in the direct outdoor air-conditioning air conditioner 10. Therefore, as described above, the humidifier 12 shown in FIG. 1 is not necessarily required. This is because, as described above, in the situation where the humidity of the outside air is low and humidification is required, the present method can be dealt with by directly shutting down the outside-air-use type air conditioner 10. Similarly, although not shown in FIG. 1, it is not necessary to mount a dehumidifying function directly on the outside-air-use type air conditioner 10. This is because, in a situation where the humidity of the outside air is high and dehumidification is necessary, this method can be dealt with by directly shutting down the air-conditioning air conditioner 10.

  Thus, in this method, energy for humidification and dehumidification is not necessary, and an energy saving effect is obtained. Alternatively, the configuration for humidification and the configuration for dehumidification do not need to be directly provided in the outside-air-use air conditioner 10, so that the configuration can be simplified and the cost can be reduced.

  Here, the overall controller 100 also performs opening / closing control of the damper 15, the return damper 8, the exhaust damper 9, and the like according to the mode determination result, for example. The overall controller 100 may further perform operation control of the direct air conditioner 10, the indirect air conditioner 20, and the like according to the mode determination result. However, the present invention is not limited to this example. The overall controller 100 notifies the mode determination result directly to the air conditioner 10, the indirect air conditioner 20, etc. so that the direct air conditioner 10, the indirect air conditioner 20, etc. perform operation control according to the notification contents. May be. Although not specifically illustrated, the direct air conditioner 10, the indirect air conditioner 20, and the like are provided with a controller having an arithmetic processor, a memory, and the like, and this controller performs operation control of the apparatus itself. One example thereof is disclosed in Patent Document 4 and the like, but is not limited to this example.

The damper opening / closing control has already been described.
An example of operation control is shown in FIGS. 6A, 6B, and 6C, which will be described below. However, since the examples shown in FIGS. 6A, 6B, and 6C correspond to the configuration example shown in FIG. 9, first, FIG. 9 will be described below.

FIG. 9 is a configuration example of the indirect outside air-use type air conditioner (indoor unit 20 and outdoor unit 30).
In addition, as already stated, the example except the structure of the said patent document 2 etc. is shown here, The cold water system which supplies the cold water collectively produced | generated outside to each indoor unit 20 (its cold water coil 22) The example of a structure which has is shown.

  In the illustrated example, the indoor unit 20 includes a heat exchanger such as a brine coil 21 and a cold water coil 22, an indoor fan 23, and the like. In each of these heat exchangers, cold water and the like supplied via the brine pipe 31 and the cold water pipe 37 pass, and the return air RA passes. As a result, the return air RA is cooled by cold water or the like to decrease in temperature and become cool air, and is sent to the server room 4 as the supply air SA by the indoor fan 23.

  Here, the brine coil 21 is a part of the “configuration as an indirect outside air cooler”, and the cold water coil 22 is a part of the “configuration as a general air conditioner”. “Configuration as an indirect outdoor air cooler” includes the brine coil 21, the outdoor fan 32, the heat exchanger 33, the brine pump 34, and the like in the outdoor unit 30, the illustrated brine pipe 31, and the like.

  The brine that has passed through the brine coil 21 and increased in temperature by heat exchange with the return air RA as described above is returned to the heat exchanger 33 via the brine pipe 31, and heat exchange with the outside air OA is performed in the heat exchanger 33. Is done. Here, when the temperature of the brine is higher than the temperature of the outside air OA, the brine is cooled by the outside air and the temperature is lowered. Note that this is a state in which the brine pump 34 is in operation, and when the brine pump 34 is stopped, water is not passed through the brine coil 21, and the “indirect outside air cooler” is not functioning. At this time, the outdoor fan 32 is also stopped.

  Further, in this example, the indirect air conditioner (indoor unit) 20 further includes a chilled water generator (chiller, turbo chiller, etc.) 36, a chilled water pump group 35, and a chilled water pipe 37 as “configuration as a general air conditioner”. Etc. are also provided outside the aircraft. The cold water that has passed through the cold water coil 22 and increased in temperature by heat exchange with the return air RA as described above is returned to the cold water generator 36 via the cold water pipe 37. The cold water generator 36 has a configuration in which the temperature of the cold water can be lowered even when the outside air temperature is high. The cold water cooled by the cold water generator 36 is pumped by the cold water pump group 35 and supplied again to the cold water coil 22 through the cold water pipe 37.

  In the state where the cold water generator 36 and the cold water pump group 35 are stopped, the cold water is not supplied to the cold water coil 22 and the “general air conditioner” is substantially stopped. However, as shown in the figure, the cold water generator 36 and the like are configured to be shared by a plurality of indirect air conditioners (indoor units) 20, and therefore the cold water generator 36 and the like are basically stopped without being stopped. You may make it respond | correspond by carrying out open / close control of the valve not shown provided on 37. FIG. That is, by closing a valve corresponding to an arbitrary indirect air conditioner (indoor unit) 20, the supply of cold water to the indirect air conditioner (indoor unit) 20 is stopped. Is substantially in a state where the function of the general air conditioner is stopped.

In the case of the configuration example shown in FIG. 9, for example, the operation control shown in FIGS. 6A, 6B, and 6C is performed.
First, the operation control in the mode C will be described with reference to FIG.

  In the case of mode C, in the example shown in FIG. 6C, first, the air conditioner 10 is directly stopped. Further, the operation of the outdoor fan 32 and the brine pump 34 is also stopped, thereby stopping the water flow to the brine coil 21. On the other hand, water flow to the cold water coil 22 is performed, and the indoor fan 23 is in an operating state. Although not shown in the drawing, as described above, while the cold water generator 36 and the cold water pump group 35 are in operation (for example, when a valve (not shown) is open), water is passed through the cold water coil 22. .

Next, with reference to FIG. 6B, the operation control in the mode B will be described.
In the case of mode B, in the example shown in FIG. 6B, first, the air conditioner 10 directly stops operation. On the other hand, all the configurations of the indirect air conditioner 20 and the like are in an operating state. That is, the outdoor fan 32 and the brine pump 34 are put into an operating state, and water is passed through the brine coil 21. The chilled water generator 36 and the chilled water pump group 35 are also set in an operating state (for example, a valve (not shown) is opened), and water is passed through the chilled water coil 22. Of course, the indoor fan 23 is also in an operating state.

  In the case of mode B, the return air RA is cooled to a predetermined set temperature by the cold water coil 22 after the temperature is lowered by the brine coil 21. In other words, the load on the “general air conditioner” is reduced as compared with the case of mode C, and thus power consumption is less than that of mode C. However, the present invention is not limited to this example. In Mode B, for example, an “indirect outside air cooler” may be operated independently. This is particularly applicable when the temperature of the outside air satisfies the condition of mode A, but the mode (B) is selected because the humidity (dew point temperature) does not satisfy the condition.

Next, the operation control in the mode A will be described with reference to FIG.
In the case of mode A, in the example shown in FIG. 6A, the air conditioner 10 is directly in the operating state. And among the structures of the said indirect air conditioner 20 grade | etc., Only the indoor fan 23 is made into an operation state, and others are stopped.

Finally, FIG. 10 shows a schematic configuration diagram (external view and the like) of the indirect outside air utilization type air conditioner 20 and the like when an air conditioner using a vapor compression refrigeration cycle such as Patent Document 2 is provided.
Hereinafter, FIG. 10 will be briefly described.

  Among the components shown in the figure, the components related to the vapor compression refrigeration cycle are an evaporator 51, a condenser 54, a compressor 56, and the like. Further, the configuration related to the “indirect outside air cooler” is the sensible heat exchangers 52 and 55, the brine pump 57, and the like. Further, an indoor fan 53 is provided in the indoor unit, and an outdoor fan 59 is provided in the outdoor unit.

  The evaporator 51 and the sensible heat exchanger 52 are provided in the indoor unit, and the return air RA sucked into the indoor unit by the indoor blower 53 passes through the sensible heat exchanger 52 and the evaporator 51 in this order. Then, the air is cooled and supplied to the server room 4 or the like as the supply air SA.

  The condenser 54 and the sensible heat exchanger 55 are provided in the outdoor unit, and the outside air OA sucked into the outdoor unit by the outdoor blower 59 passes through the sensible heat exchanger 55 → the condenser 54 in this order, and the temperature is increased. It rises and is discharged outside the building as exhaust EA.

  In addition, for example, even when the dry air temperature and humidity (dew point temperature) of the outside air satisfy the above predetermined conditions, if the outside air contains a lot of contaminants such as suspended dust and chemical substances (Nox, Sox, etc.) The direct outdoor air-conditioning type air conditioner 10 may be stopped. For example, by installing a dust meter directly at the air outlet of the air-conditioning type air conditioner 10 or the like, the concentration of suspended particulate matter in the outside air after passing through the filter 11 is measured. When the set threshold value is exceeded, the direct outside air utilization type air conditioner 10 is stopped. Of course, this is an example, and the present invention is not limited to this example.

FIG. 11 is a functional block diagram showing the configuration of the outside-air-use air conditioning system of this example.
The outside-air-use air conditioning system in the illustrated example includes a direct outside-air-use air conditioning system 71, an inside-air circulation air-conditioning system 72, a control device 60, and the like. Note that the cooling target space shown in the figure is an indoor space in which an electronic device serving as a heating element is installed during operation, such as a room in which the server room 4 or UPS 2 is installed.

  The direct external air-conditioning air conditioning system 71 is an air conditioning system that cools the electronic device directly by the outside air by passing the outside air through the space to be cooled. For example, the direct outside air use air conditioning system 71 includes, for example, the direct outside air use type air conditioner 10 and a configuration for allowing outside air to pass through the server room 4 (air supply shaft 5, exhaust shaft 6, exhaust damper 9, damper). 15 etc.). In the above example, the fan (indoor fan 23) of the indirect outside air-utilizing air conditioner (indoor unit) 20 is also added, but the present invention is not limited to this example.

  The inside air circulation type air conditioning system 72 cools the return air (warm air) from the space to be cooled to cool air without flowing outside air into the space to be cooled, and supplies the cold air to the space to be cooled. It is an air conditioning system that cools equipment. In other words, the air-conditioning system circulates the inside air (the air in the building), cools the inside air when it becomes warm, and cools it to supply it to the electronic equipment.

  The control device 60 includes an operation mode determination / control unit 61 that determines whether to directly operate the outside-air-use air conditioning system 71 or the inside-air circulation type air-conditioning system 72 based on the temperature of the outside air.

  The inside air circulation type air conditioning system 72 includes, for example, the indirect outside air utilization type air conditioner (the indoor unit 20 and the outdoor unit 30) and a configuration for circulating the inside air (the air supply shaft 5, the return damper 8 and the like). ).

  The control device 60 operates either the direct outside air use air conditioning system 71 or the inside air circulation type air conditioning system 72. For example, in the case of operating the outdoor air-conditioning air conditioning system 71 directly, in the case of the above example, the direct outdoor-air-conditioning air conditioner 10 is set in the operating state, and the exhaust damper 9 and the damper 15 are set in the “open” state. The return damper 8 is in the “closed” state. Further, for example, when the inside air circulation type air conditioning system 72 is operated, in the above example, the indirect outside air utilization type air conditioner (the indoor unit 20 and the outdoor unit 30) is put into an operating state, and the exhaust damper 9 and the damper are operated. 15 is in a “closed” state, and the return damper 8 is in an “open” state.

  The system further includes an outside air temperature measurement unit 73 that measures the dry bulb temperature and the dew point temperature of the outside air. Then, the operation mode determination / control unit 61 of the control device 60 directly outputs the outside air when, for example, the measured dry bulb temperature and dew point temperature of the outside air satisfy a predetermined condition as air to be supplied to the cooling target space. The use air conditioning system 71 is operated, and when the condition is not satisfied, the inside air circulation type air conditioning system 72 is operated.

Here, it can be said that the inside air circulation type air conditioning system 72 includes an indirect outside air conditioner that indirectly exchanges heat between the outside air and the return air, and a general air conditioner.
The operation mode determination / control unit 61 operates the indirect outside air conditioner when the outside air cold air is available when the inside air circulation type air conditioning system 72 is operated so as not to satisfy the predetermined condition. The case where the cold air of the outside air can be used is, for example, a case where the dry bulb temperature of the outside air is lower than the temperature of the return air.

  The operation mode determination / control unit 61 determines that the predetermined condition is satisfied, for example, when the measured dry bulb temperature and dew point temperature of the outside air are within the server intake air condition range. An example of this determination method is the processing example of FIG. 7 described above, but is not limited to this example. However, as described above, the dry bulb temperature may have no lower limit condition in the original server intake air condition range.

  Alternatively, the operation mode determination / control unit 61, for example, has a measured outside air dry bulb temperature equal to or lower than a set temperature SA related to the air supplied to the cooling target space, and the measured outside air dew point temperature is preset. When it is equal to or greater than a predetermined threshold, it is determined that a predetermined condition is satisfied. An example of this determination method is the processing example of FIG. 8 described above, but is not limited to this example.

  For example, the inside air circulation type air conditioning system 72 includes an indirect outside air conditioner and a general air conditioner. The general air conditioner is, for example, an air conditioner of a compression refrigeration cycle or an air conditioner of a cold water system. An example of a cold water system air conditioner is shown in FIG.

  The inside air circulation type air conditioning system 72 has a first mode in which the indirect outside air conditioner and the general air conditioner are used in combination, and a second mode in which the general air conditioner is operated alone. When operating the inside-air circulation type air conditioning system 72, the operation mode determination / control unit 61 of the control device 60 operates in one of the first mode and the second mode. For example, the operation mode determination process is as follows.

  First, it further has a warm air temperature measurement unit 74 that measures the temperature of the return air (warm air) from the space to be cooled. The operation mode determination / control unit 61 of the control device 60 operates in the second mode when, for example, the measured outside air dry bulb temperature is equal to or higher than the measured temperature of the return air.

  Alternatively, the operation mode determination / control unit 61 of the control device 60 operates in the first mode when, for example, the measured outside air dry bulb temperature is lower than the return air temperature. Of course, as described above, this is based on the case where it is determined that the inside air circulation type air conditioning system 72 is to be operated. Therefore, it is assumed that the measured dry-bulb temperature and dew point temperature of the outside air do not satisfy the “predetermined condition as air to be supplied to the cooling target space”. Therefore, there is a condition for operating in the first mode not only for the dry bulb temperature but also for the dew point temperature.

  However, when the measured outside air dry bulb temperature is lower than the measured temperature of the return air and is equal to or higher than a predetermined value (for example, the set value 24 ° C. or the upper limit value 27 ° C.), the dew point temperature is irrelevant, The operation may be performed in the first mode.

  As described above, according to the outside air-conditioning air conditioning system of this example, the outside air-conditioning system that uses both the direct outside air cooling and the indirect outside air cooling is used, and the outside air cooling is used more effectively, thereby further saving energy. Can be achieved. In particular, further energy saving can be achieved by effectively using the indirect outside air conditioner. For example, in the case of a configuration with only a direct outside air cooler, it does not function when the outside air temperature exceeds the set value (24 ° C.) or the upper limit value (27 ° C.). On the other hand, in this method, even in such a case, it is possible to effectively use the cold heat of the outside air by operating the indirect outside air conditioner by setting the B mode. That is, the temperature of the return air can be lowered by heat exchange with the outside air by the indirect outside air conditioner.

  Alternatively, even if the outside air temperature is less than the set value (24 ° C.) or the upper limit value (27 ° C.), if the outside air humidity (dew point temperature) does not satisfy the predetermined condition, the configuration of only the outside air cooler directly If so, it is necessary to cope with the dehumidifying function or the humidifying function. On the other hand, in this method, in such a case, it becomes possible to cope with the above-described B mode by operating the indirect outside air conditioner, so that it is not necessary to provide a dehumidifying function or a humidifying function directly in the outside air cooling device. . Therefore, further energy saving and cost reduction can be achieved.

1 Outside air intake gallery 2 UPS
DESCRIPTION OF SYMBOLS 3 Battery 4 Server room 5 Supply shaft 6 Exhaust shaft 7 Outside air intake grating 8 Return damper 9 Exhaust damper 10 Direct outside air use type air conditioner 11 Filter 12 Humidifier 13 Cooling coil 14 Fan 15 Damper 20 Indirect outside air use type air conditioning Machine (indoor unit)
21 Brine coil 22 Chilled water coil 23 Indoor fan 30 Indirect outside air type air conditioner (outdoor unit)
31 Brine piping 32 Outdoor fan 33 Heat exchanger 34 Brine pump 35 Chilled water pump group 36 Chilled water generator (chiller, turbo refrigerator, etc.)
37 Cold water pipe 41 Server device 51 Evaporator 52 Sensible heat exchanger 53 Indoor blower 54 Condenser 55 Sensible heat exchanger 56 Compressor 57 Brine pump 60 Controller 61 Operation mode determination / control unit 71 Direct air use air conditioning system 72 Inside air circulation Type air conditioning system 73 Outside air temperature measuring unit 74 Warm air temperature measuring unit 100 Overall controller

Claims (8)

A direct outside air-conditioning system that cools the electronic device with the outside air by allowing the outside air to pass through the space to be cooled having the electronic device, and
An internal air circulation type air conditioning system that cools the return air from the cooling target space to cool air without flowing outside air into the cooling target space, and cools the electronic device by supplying the cold air to the cooling target space; ,
A controller for operating either the direct outside air-use air conditioning system or the inside air circulation type air conditioning system;
The control device has an operation mode determination / control unit for determining whether to operate the direct external air-conditioning air conditioning system or the internal air circulation type air-conditioning system based on the temperature of the external air. system. Outside temperature measuring means for measuring the dry bulb temperature and dew point temperature of the outside air,
The operation mode determination / control means of the control device is configured to perform the direct outside air-conditioning when the measured dry-bulb temperature and dew point temperature of the outside air satisfy a predetermined condition as air to be supplied to the cooling target space. 2. The outside-air-use air conditioning system according to claim 1, wherein the system is operated and the inside-air circulation type air conditioning system is operated when the condition is not satisfied. The operation mode determination / control means of the control device is:
When the condition for operating the direct outside air-conditioning system is satisfied and the measured dry bulb temperature of the outside air is lower than a predetermined temperature,
3. The outside air-conditioning system according to claim 2, wherein the outside air-conditioning system mixes the outside air with the return air and supplies the air to the cooling target space. The inside air circulation type air conditioning system includes an indirect outside air conditioner that indirectly exchanges heat between the outside air and the return air, and a general air conditioner,
The operation mode determination / control unit operates the indirect outside air conditioner when the outside air cooling air is available when the inside air circulation type air conditioning system is operated so as not to satisfy the predetermined condition. The air-conditioning system using outside air according to claim 2.   5. The outside air-conditioning system according to claim 4, wherein the cold air of the outside air is usable when the dry bulb temperature of the outside air is lower than the temperature of the return air.   The operation mode determination / control means of the control device determines that the predetermined condition is satisfied when the measured dry-bulb temperature and dew point temperature of the outside air are within a server intake air condition range. The air-conditioning system using outside air according to claim 2 characterized by the above-mentioned.   The operation mode determination / control means of the control device is configured such that the measured outside air dry bulb temperature is equal to or lower than a set temperature related to the cool air supplied to the cooling target space, and the measured outside air dew point temperature is preset. The outdoor air-conditioning system according to claim 2, wherein the predetermined condition is determined to be satisfied when the predetermined threshold is exceeded. 5. The outside air-use air conditioning system according to claim 4, wherein the general air conditioner is an air conditioner of a compression refrigeration cycle or an air conditioner of a cold water system.