JP5677188B2 - Air conditioning equipment - Google Patents

Description

  The present invention relates to an air conditioner suitable for air-conditioning a room such as a computer room in a data center in which a large number of high-heat-generating electronic devices such as servers are installed.

  In a conventional general air conditioning facility, when the air conditioning area is wide, a plurality of refrigerators supplying cold water to a plurality of air conditioners, and water is circulated between the respective refrigerators connected to the respective refrigerators. And a plurality of cooling towers for cooling the refrigerator.

  By the way, in the case of having a plurality of cooling towers, in Patent Document 1 below, the cooling towers are connected in parallel from the viewpoint of energy saving, and the rotation speed of the fans of each cooling tower is cooled based on the measurement result of the cooling water flow rate. It has been proposed to control each tower.

JP 2007-333361 A

In the technique disclosed in Patent Document 1, a temporary energy saving measure is taken, but satisfactory results cannot be obtained when the entire air conditioning equipment is taken into consideration.
By the way, when air-conditioning a computer room where a large number of high-heat-generating electronic devices such as servers are installed, air conditioning may be necessary not only in summer but also in the middle of spring or autumn or in winter. Since the outside air temperature is lower in the intermediate season and winter season than in the summer season, if the outside air can be used effectively, it can be expected that further energy saving can be achieved as compared with the technique disclosed in Patent Document 1.
In view of the above circumstances, an object of the present invention is to provide an air conditioning facility that can further save energy by effectively using outside air.

In order to solve the above-described problems, an air conditioning system according to a first aspect of the present invention includes a plurality of refrigerators that supply cold water to an air conditioner, and water is circulated between the refrigerators connected to the respective refrigerators. And a plurality of cooling towers for cooling the refrigerator, wherein the first operation mode is to obtain cold water to be supplied to the air conditioner by operating the refrigerator according to the condition of outside air. And a second operation mode in which at least some of the plurality of cooling towers are connected in series without operating the refrigerator, and cold water supplied directly to the air conditioner is obtained from the cooling towers connected in series. An operation mode selection means for selectively selecting, and the selection of the operation mode by the operation mode selection means is calculated and determined by the cooling load of the air conditioner, the capacity of the cooling tower and the wet bulb temperature of the outside air straight The first temperature, which is the temperature of the cooling water flowing out from the last cooling tower connected to, is the cooling water flowing out from the last cooling tower connected in series when the second operation mode is adopted. The first operation mode is selected when a second temperature that is a temperature is exceeded, and the second operation mode is selected when the first temperature is equal to or lower than the second temperature. And

According to the present invention, when the outside air temperature is high as in summer, the operation mode is switched to the first operation mode to operate the refrigerator and obtain cold water supplied to the air conditioner by the refrigerator. Further, in the intermediate season or winter season, the air conditioner is directly switched from the cooling tower connected in series by switching at least some of the cooling towers in series without switching to the second operation mode and operating the refrigerator. Get cold water to supply to.
Here, since a plurality of cooling towers are connected in series, the cooling water temperature after obtaining these cooling towers is lower than that when cooling with only one cooling tower. It is done. For this reason, the second operation mode can be adopted even in an intermediate season when the outside air temperature is not so low.
In addition, the selection of the operation mode by the operation mode selection means is uniquely determined by the cooling load of the air conditioner, the capacity of the cooling tower and the wet bulb temperature of the outside air, and the configuration of the operation mode selection means can be facilitated.
In actual control, an intermediate condition region is provided including a portion that separates both of the first operation mode and the second operation mode so that the switching between the first operation mode and the second operation mode does not occur frequently. When in the condition region, it is preferable to forcibly set to the first or second operation mode.

  According to a second aspect of the present invention, in the air conditioning equipment according to the first aspect, a hermetic cooling tower is used as the cooling tower.

  In this case, since the cooling water supplied to the cooling tower does not come into direct contact with the outside air, the cooling water is not contaminated by impurities in the air. For this reason, it is possible to prevent corrosion and scale from adhering to the heat exchanger in the air conditioner that directly supplies cooling water. In addition, when switching to the first operation mode, even if the cooling water from the cooling tower enters the circulation line on the air conditioner side of the refrigerator, the corrosion and scale due to the heat exchange accompanying them adheres. Can prevent

A third aspect of the present invention is the air conditioning system according to the first or second aspect, wherein the outgoing pipe for transferring cold water from the refrigerator to the air conditioner and the used cold water returning from the air conditioner to the refrigerator are transferred. A return pipe, a cooling pipe connecting the refrigerator and the cooling tower, and a branch return pipe branched from the return pipe is based on the flow of cooling water among the cooling towers connected in series. The branch outgoing pipe branched from the outgoing pipe is connected to the cooling pipe associated with the first cooling tower, and the last cooling tower based on the flow of the cooling water among the cooling towers connected in series. It is connected to the accompanying cooling pipe.

  In this case, when switching between the first operation mode and the second operation mode, a part of the outgoing pipe, the return pipe and the cooling pipe can be used in common, and the total length of the pipes used can be shortened. As a result, the cost can be reduced.

  According to the first aspect of the present invention, when the outside air temperature is high as in summer, the operation mode is switched to the first operation mode to operate the refrigerator and obtain cold water to be supplied to the air conditioner by the refrigerator. Further, in the intermediate season or winter season, the cooling mode is switched to the second operation mode, and a plurality of cooling towers are connected in series without operating the refrigerator, and the chilled water supplied directly to the air conditioner from these series connected cooling towers is supplied. obtain. Since the above operation becomes possible, the outside air can be effectively used, and as a result, further energy saving can be achieved.

  According to the invention of claim 2, since the cooling water supplied to the cooling tower does not come into direct contact with the outside air, the cooling water is not contaminated by impurities in the air, etc. Therefore, the heat exchanger in the air conditioner Corrosion and scale adhesion can be prevented.

  According to the invention of claim 3, the selection of the operation mode by the operation mode selection means is uniquely determined by the cooling load of the air conditioner, the capacity of the cooling tower, and the wet bulb temperature of the outside air. The configuration can be facilitated.

  According to invention of Claim 4, when switching a 1st operation mode and a 2nd operation mode, a part of an outward pipe, a return pipe, and a cooling pipe can be used in common, and the full length of these pipes to be used is reduced. As a result, the cost can be reduced.

It is a figure which shows the structure of the air conditioning equipment of embodiment of this invention. It is a figure which shows the 1st operation mode of the air conditioning equipment of embodiment of this invention. It is a figure which shows the 2nd operation mode of the air conditioning equipment of embodiment of this invention. It is a flowchart which shows the content of the control part of the air conditioning equipment of embodiment of this invention. It is a figure which shows the performance curve of the cooling tower used with the air conditioning equipment of embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an air conditioning facility according to an embodiment of the present invention. The air conditioner 1 includes an air conditioner 3 disposed in an air conditioning target room 2 that is a computer room of a data center in which high heat generating electronic devices such as servers are installed, and a plurality of refrigeration units that supply cold water to the air conditioner 3. And a plurality of cooling towers 5 that are connected to the refrigerators 4 and circulate water between the refrigerators 4 to cool the refrigerators 4.
Here, the individual refrigerators 4 and the cooling towers 5 are paired with each other, and at least the cooling towers 5 are arranged side by side in a horizontal row as shown in FIG.

  From the refrigerator 4 to the air conditioner side, an outward branch pipe 6 and a return side branch pipe 7 on the refrigerator side respectively extend, and the forward side branch pipe 6 and the return side branch pipe 7 are gathered to form an outward pipe 8 and a return pipe 9. Connected to. The forward pipe 8 is connected to the forward branch pipe 10 on the side of the air conditioner connected to the air conditioner 3 at the tip thereof, and supplies cold water from the refrigerator 4 side to the air conditioner 3 through the forward branch pipe 10. Further, the return pipe 9 is connected at its tip to a return side branch pipe 11 on the air conditioner side connected to the air conditioner 3, and the cold water is returned from the air conditioner 3 to the refrigerator 4 side through the return side branch pipe 11. It is.

  The refrigerator 4 and the cooling tower 5 corresponding to each other are connected to each other by an outward cooling pipe 12 and a return cooling pipe 13. Outward cooling pipes 12 and return side cooling pipes 13 of adjacent cooling towers of the cooling towers 5 arranged in the horizontal row are connected by a communication pipe 14. Further, on-and-off valves are provided in the forward cooling pipe 12, the return-side cooling pipe 13 and the communication pipe 14, and by opening and closing these opening and closing valves, the pair of the refrigerator 4 and the cooling tower 5 are provided. Switching between the state in which the cooling towers 5 are connected and the state in which the cooling towers 5 are connected in series is possible. The opening / closing operation of the opening / closing valve will be described in detail later.

  On the other hand, a branch forward pipe 15 is branched from the forward pipe 8, and this branch forward pipe 15 is the last cooling tower (see FIG. 1 is connected to the forward cooling pipe 12A associated with the cooling tower at the right end in FIG. On the other hand, a branch return pipe 16 is branched from the return pipe 9, and this branch return pipe 16 is the first cooling tower based on the flow of the cooling water among the cooling towers connected in series (in FIG. 1). It is connected to a return side cooling pipe 13A associated with the cooling tower at the left end.

  At the connecting portion between the outgoing pipe 8 and the branch outgoing pipe 15, an opening / closing valve 8A and a refrigerator-side opening / closing valve 8B on the air conditioner side are provided in the outgoing pipe 8, and an opening / closing valve 15A is provided on the branch outgoing pipe 15, respectively. ing. On the other hand, the connecting portion between the return pipe 9 and the branch return pipe 16 is provided with an open / close valve 9A on the air conditioner side and an open / close valve 9B on the refrigerator side through the return pipe 9 and an open / close valve 16A through the branch return pipe 16 respectively. It is disguised.

  At the connection between the branch outgoing pipe 15 and the outgoing cooling pipe 12A, an opening / closing valve 15B is provided on the branch outgoing pipe 15, and an opening / closing valve 12B on the refrigerator side and an opening / closing valve 12C on the cooling tower are provided on the branch outgoing pipe 12A. It is intervened. On the other hand, at the connection between the branch return pipe 16 and the return side cooling pipe 13A, the branch return pipe 16 has an opening / closing valve 16B, and the branch return pipe 13A has a refrigerator side opening / closing valve 13B and a cooling tower side opening / closing valve 12C. Are intervened.

  At each connection portion between the forward cooling pipe 12 and the communication pipe 14, the forward cooling pipe 12 is provided with a chiller side opening / closing valve 12D and a cooling tower side opening / closing valve 12E, and the communication pipe 14 is provided with an opening / closing valve 14A. It is intervened. On the other hand, at each connection portion between the return side cooling pipe 13 and the communication pipe 14, the return side cooling pipe 13 has a refrigerator side on-off valve 13D and a cooling tower side on-off valve 13E, and the communication pipe 14 has an on-off valve 14B. Are intervened.

  Each of the above open / close valves is opened / closed by a signal from the control unit (operation mode selection means) 18, thereby operating the refrigerator 4 to obtain cold water to be supplied to the air conditioner 3 by the refrigerator 4. The second operation mode in which a plurality of cooling towers 5 are connected in series without operating the refrigerator 4 and the cold water supplied to the air conditioner 3 from the serially connected cooling towers 5 is obtained is alternatively selected. The

  That is, in the first operation mode, the on-off valves 9A, 9B, 12B, 12C, 12D, 12E, 13B, 13C, 13D, and 13E are in the “open state”, and the on-off valves 14A, 14B, 15A, 15B, 16A, and 16B, respectively. Become “closed” respectively. Thereby, in the piping connecting the air conditioner 3, the refrigerator 4, and the cooling tower 5, the flow of the cooling water and the cold water shown in FIG. 2 is secured. In the second operation mode, the on-off valves 8A, 9A, 12C, 12E, 13C, 13E, 14A, 14B, 15A, 15B, 16A, and 16B are in the “open state”, and the on-off valves 8B, 9B, 12B, and 12D, respectively. , 13B and 13D are each in a “closed state”. Thereby, in the piping which connects the air conditioner 3, the refrigerator 4, and the cooling tower 5, the flow of the cooling water which also serves as the cold water shown in FIG. 3 is secured.

Next, the operation of the air conditioning equipment having the above configuration will be described with reference to FIGS. FIG. 4 is a flowchart showing the contents of the control unit of the air conditioning equipment.
[Step 1]
First, the cooling water temperature Tw0 flowing out from the outlet of the cooling tower 5 is set. This cooling water temperature Tw0 is, for example, the temperature of the cooling water flowing out from the last cooling tower 5 connected in series when the second operation mode is adopted.

[Step 2]
Next, the wet bulb temperature of the outside air is measured (twb). In this measurement, the wet bulb temperature of the outside air may be directly measured, or the dry bulb temperature and the relative humidity of the outside air may be measured and calculated from these values.

[Step 3]
Next, the cooling load is measured. Here, the power consumption of the server arranged in the air conditioning target room 2 which is a computer room of the data center is measured.
[Step 4]
A necessary cooling water amount Q (kwH / 10) that can correspond to the measured cooling load is calculated.

[Step 5]
Based on the wet bulb temperature twb of the outside air calculated as described above, the cooling water flow rate, and the performance curve of the cooling tower 5, the cooling outflow from the outlet of each cooling tower 5 when the cooling towers 5 are arranged in series. The water temperature Tw2 is calculated and calculated.
FIG. 5 is a diagram showing a performance curve of a cooling tower (cooling capacity 800 RT, design water amount 10400 l / min) used in the air conditioning equipment according to the embodiment of the present invention. In this figure, the horizontal axis represents the wet bulb temperature of the outside air, and the vertical axis represents the circulating water outlet temperature, that is, the cooling water temperature flowing out from the outlet.

  For example, when the temperature of the wet bulb of the outside air is 15 ° and the temperature of the cooling water returned from the air conditioner is 37 ° C., the temperature of the cooling water flowing out from the first cooling tower is as shown in FIG. 29 ° C. The cooling water at this temperature cannot cope with the cooling load when supplied to the air conditioner 3. The cooling water flowing out from the first cooling tower is supplied to the second cooling tower. Thereafter, the steps are repeated in order and finally supplied to the fifth cooling tower. When the cooling water temperature at this time is examined for each cooling tower, the cooling water at 29 ° C. is supplied to the second cooling tower, and the cooling water temperature flowing out from the second cooling tower becomes 24,1 ° C. Cooling water at 24.1 ° C. is supplied to the third cooling tower, and the temperature of the cooling water flowing out from the cooling tower is 21 ° C. Cooling water at 21 ° C. is supplied to the fourth cooling tower, and the temperature of the cooling water flowing out from it becomes 19 ° C. Cooling water at 19 ° C. is supplied to the fifth cooling tower, and the temperature of the cooling water flowing out from the cooling tower is 17.6 ° C.

[Step 6]
That is, for example, when five units are connected in series, 17.6 ° of cooling water is obtained from the fifth cooling tower under the above conditions. It is determined whether or not the cooling water temperature Tw2 (n) is equal to or lower than the cooling water temperature Tw0 set in step 1.
[Step 7]
When the cooling water temperature Tw2 (n) exceeds the cooling water temperature Tw0, the cooling operation using the refrigerator, that is, the first operation mode shown in FIG. 2 is selected.

[Step 8]
On the other hand, when the cooling water temperature Tw2 (n) is equal to or lower than the cooling water temperature Tw0, a plurality of (for example, five) cooling towers are connected in series without operating the refrigerator, and these cooling towers are connected in series. The second operation mode shown in FIG. 3 is selected, in which cold water supplied directly to the air conditioner is obtained.
For example, in the example shown in FIG. 5, the cooling water temperature Tw2 (n) flowing out from the fifth cooling tower is 17.6 °, and this cooling water temperature is the cooling temperature set in step 1. Since it is 20 degrees C or less of water temperature Tw0, 2nd operation mode is selected.

  According to the present invention, when the outside air temperature is high as in summer, the operation mode is switched to the first operation mode, the refrigerator 4 is operated, and cold water supplied to the air conditioner 3 by the refrigerator 4 is obtained. Further, in the intermediate season or winter season, the operation mode is switched to the second operation mode, and a plurality of cooling towers 5 are connected in series without operating the refrigerator 4 and supplied directly to the air conditioners 3 from the cooling towers 5 connected in series. Get cold water. Since the above operation becomes possible, the outside air can be effectively used, and as a result, significant energy saving can be achieved.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the above-described embodiment, an on-off valve interposed in the piping is used to switch the piping of the air conditioning equipment between the first operation mode and the second operation mode, but the present invention is not limited to this. A valve or a three-way valve, or a combination of these and a normal on-off valve may be used to switch to each operation mode.

  Moreover, in the said embodiment, although the example which used all the cooling towers 5 which have the 2nd operation mode arranged in series was shown, it is not restricted to this, Some of them, for example, 4 sets, for example Alternatively, only three units may be used in series. Further, although all the cooling towers are arranged in series as shown in FIG. 3, the cooling water may be circulated with the fans of some of the cooling towers stopped.

DESCRIPTION OF SYMBOLS 1 Air-conditioning equipment 2 Air-conditioning object room 3 Air conditioner 4 Refrigerator 5 Cooling tower 6 Outlet side branch pipe 7 Return side branch pipe 8 Outlet pipe 9 Return pipe 10 Air conditioner side branch pipe 11 Air conditioner side branch pipe 12 Outlet side cooling pipe 12A Flow of cooling water Return side cooling pipe 13A associated with the last cooling tower with reference to the return side Cooling pipe 13A Return side cooling pipe 14 associated with the first cooling tower based on the flow of the cooling water 14 Communication pipe 15 Branching outward pipe 16 Branching return Pipe 18 control unit (operation mode selection means)

Claims (3)

In an air conditioning facility comprising a plurality of refrigerators for supplying cold water to an air conditioner, and a plurality of cooling towers connected to each of these refrigerators to circulate water between the refrigerators and cool the refrigerator ,
A first operation mode in which the refrigerator is operated to obtain cold water to be supplied to the air conditioner by the refrigerator, and at least some of the plurality of cooling towers without operating the refrigerator in accordance with the state of outside air An operation mode selection means for alternatively selecting a second operation mode for obtaining cold water to be supplied to the air conditioner directly from the cooling towers connected in series .
Selection of the operation mode by the operation mode selection means is
The first temperature, which is the temperature of the cooling water flowing out from the last cooling tower connected in series, calculated by the cooling load of the air conditioner, the capacity of the cooling tower and the wet bulb temperature of the outside air, When the second temperature which is the temperature of the cooling water flowing out from the last cooling tower connected in series when the second operation mode is adopted is exceeded, the first operation mode is selected,
The air conditioner characterized in that the second operation mode is selected when the first temperature is equal to or lower than the second temperature .   The air conditioning equipment according to claim 1, wherein a closed cooling tower is used as the cooling tower. An outgoing pipe for transferring cold water from the refrigerator to the air conditioner;
A return pipe for transferring the used cold water returning from the air conditioner to the refrigerator;
A cooling pipe connecting the refrigerator and the cooling tower;
A branch outgoing pipe branched from the outgoing pipe is connected to a cooling pipe associated with the last cooling tower based on the flow of cooling water among the cooling towers connected in series,
The branch return pipe branched from the return pipe is connected to a cooling pipe associated with a first cooling tower based on a flow of cooling water among the cooling towers connected in series. The air conditioning equipment according to 1 or 2 .

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