Cooling system and cooling method for electronic equipment

Abstract

This cooling system comprises a plurality of processing devices, and a computational load distributor that calculates a computational load amount to be distributed to each processing device and causes each processing device to execute computation in accordance with the computational load amount. The cooling system comprises: a water passage through which a refrigerant flows into or out from each heat sink provided for each processing device; a plurality of variable valves that adjust an inflow amount of the refrigerant for the respective heat sinks; a plurality of inflow-side temperature sensors that measure the inflow temperature of the refrigerant flowing into the respective heat sinks; a plurality of outflow-side temperature sensors that measure the outflow temperature of the refrigerant flowing out from the respective heat sinks; and a refrigerant temperature control device. The refrigerant temperature control device comprises: a control unit that receives the computational load amount of each processing device calculated by the computational load distributor; a temperature detection unit that detects the inflow temperature and the outflow temperature of the refrigerant for each of the processing devices measured by the plurality of inflow-side temperature sensors and outflow-side temperature sensors; and a valve adjustment unit that adjusts the degree of opening of the plurality of variable valves individually in accordance with the computational load amount and at least the outflow temperature of the refrigerant of each processing device.

Description

Cooling system and cooling method for electronic device

[0001] The present invention relates to a cooling system for electronic devices, and more particularly to a cooling system and method for electronic devices, such as computers and servers installed in data centers, that locally cools electronic devices using a liquid cooling medium.

[0002] In recent years, advances in information processing technology and the development of the Internet environment have led to an increase in the amount of information required for processing. Data centers, which process large amounts of various types of information, have come into the spotlight as a business. In server rooms, for example, these data centers house a large number of electronic devices, such as computers and servers, in a centralized location, operating continuously day and night. The rack-mounting method is the mainstream for installing electronic devices in server rooms. The rack-mounting method involves stacking racks (housings) that house electronic devices divided by function in cabinets, and many such cabinets are aligned and arranged on the floor of the server room.

[0003] These electronic devices require a certain temperature environment to operate, and because this temperature environment is set relatively low for normal operation, leaving them in a high temperature environment can cause problems such as system shutdowns. For this reason, server rooms are maintained at a constant temperature using air conditioners. However, as the processing speed and processing power of these information-processing electronic devices have rapidly improved, the amount of heat they generate has also continued to rise, leading to increased demand for improved air conditioner performance. Meanwhile, with growing awareness of energy conservation in recent years, there has also been an increasing demand for lower power consumption in air conditioners, and various technologies have been proposed to efficiently cool electronic devices. For example, Patent Document 1 discloses an air conditioner comprising: "a refrigeration cycle formed by connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger by refrigerant piping; a pump cycle formed by bypassing the flow of refrigerant to the compressor and circulating the refrigerant between the indoor heat exchanger and the outdoor heat exchanger by a liquid delivery device; a calculation and control device that switches to operation using the pump cycle when, during operation using the refrigeration cycle, the temperature outside the room where an outdoor unit that houses the outdoor heat exchanger is installed becomes lower than the temperature inside the room where an indoor unit that houses the indoor heat exchanger is installed; and a liquid refrigerant supply device that supplies liquid refrigerant to the pump cycle."

[0004] Japanese Patent Application Laid-Open No. 2018-71955

[0005] As mentioned above, electronic devices in data centers are generally cooled by air conditioners. However, the heat generation density of processing devices such as central processing units (CPUs) and graphics processing units (GPUs) installed in electronic devices is increasing due to their high integration, and it is predicted that the heat generation density will reach approximately five times over the next 10 years. In order to properly cool electronic devices whose heat generation continues to increase, data centers are considering changing or converting from the conventional air-cooling method, which uses a gas such as air as a cooling medium (hereinafter referred to as a refrigerant) to a water-cooling (or liquid-cooling) method, which uses a liquid such as water as a refrigerant.

[0006] Additionally, efforts are underway to reuse the heat generated by electronic devices in data centers (hereafter referred to as waste heat). For example, Stockholm, Sweden; Bergen, Norway; and Hamina, Finland are considering reusing waste heat from data centers for district heating.

[0007] When considering waste heat reuse, in the case of air-cooling systems using air conditioners, waste heat is first transferred to air, which acts as a refrigerant. The resulting warmed air is then recovered and reused using a heat exchanger. However, in data centers, the temperature of electronic devices (specifically, processing devices) fluctuates dramatically depending on the data processing load. Therefore, air cooling systems require the air to be circulated at a temperature sufficiently low to cool the electronic devices, assuming the highest possible temperature. This results in the waste heat being dispersed into a large volume of low-temperature air, making it difficult for the air temperature to rise. Furthermore, the thermal resistance from the processing device (heat-generating element) to the air is high, resulting in a low temperature rise in the air itself. This limits the temperature of the recovered waste heat, limiting its reuse potential. Furthermore, before the waste heat can be recovered, heat is lost from the air to various facility structures within the server room, reducing the amount of waste heat available for heat recovery to approximately 50% or less. This reduces the waste heat recovery capacity and limits the viability of reuse.

[0008] On the other hand, water-cooled systems have the advantage of being able to transfer heat directly from the heating element to the water refrigerant, making it possible to recover waste heat efficiently. With water-cooled systems, the hot water generated after waste heat recovery can be used for heating buildings, swimming pools, or for businesses and industries that use hot water. However, just like with the recoverable waste heat in air-cooled systems, unless the temperature of the hot water after waste heat recovery rises to a certain level, the places where it can be reused are limited, making it less viable for business.

[0009] The present invention has been made in consideration of these problems, and aims to provide a cooling system and a cooling method that employs a water-cooling system to efficiently cool electronic devices and that can raise the temperature of the refrigerant (hot water) used for cooling and carrying waste heat to a temperature that makes it easier to reuse.

[0010] The present invention includes a plurality of means for solving at least part of the above problems, and examples thereof are as follows. That is, a cooling system for cooling electronic devices includes a plurality of processing devices and a calculation load distributor that calculates a calculation load to be distributed to the plurality of processing devices and causes the plurality of processing devices to perform calculations in accordance with the calculation load, the cooling system including: a water channel for inputting and outputting a liquid cooling medium to and from each heat sink provided for each of the processing devices; a plurality of variable valves provided for each of the processing devices and adjusting the amount of the cooling medium input to the heat sink; a plurality of input-side temperature sensors provided for each of the processing devices and measuring the input temperature of the cooling medium input to the heat sink; a plurality of output-side temperature sensors provided for each of the processing devices and measuring the output temperature of the cooling medium output from the heat sink; and a cooling medium temperature control device, the cooling medium temperature control device including a control unit that receives the calculation load for each of the processing devices calculated by the calculation load distributor; a temperature detection unit that detects the input temperature and output temperature of the cooling medium for each of the processing devices measured by the plurality of input-side temperature sensors and the plurality of output-side temperature sensors; and a valve adjustment unit that individually adjusts the opening degree of the plurality of variable valves in accordance with the calculation load for each of the processing devices and at least the output temperature of the cooling medium.

[0011] According to the present invention, the temperature of the refrigerant (hot water) after waste heat recovery is controlled so as to be raised to a temperature at which it is easier to reuse, thereby making it possible to improve the business viability of waste heat reuse.

[0012] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

[0013] FIG. 1 is a diagram showing an example of the configuration of a cooling system in the first embodiment. FIG. 2 is a diagram showing an example of the configuration of an electronic device to be cooled in the first embodiment. FIG. 3 is a diagram showing a state in which a cooling system is installed in relation to an electronic device in the first embodiment. FIG. 4 is a diagram showing an example of the configuration of a refrigerant temperature control device in the first embodiment. FIG. 5 is a diagram showing an example of a control processing procedure for refrigerant temperature by the cooling system and the refrigerant temperature control device in the first embodiment. FIG. 6 is a diagram showing an example of a processing procedure for calculation execution processing by a calculation load distributor in the electronic device in the first embodiment. FIG. 7 is a diagram showing the relationship between the calculation load of the processing device and the opening degree of the variable valve in the first embodiment. FIG. 8 is a diagram showing the relationship between the calculation load of the processing device and the opening degree of the variable valve in the first embodiment. FIG. 9 is a diagram showing an example of a control processing procedure for refrigerant temperature by the cooling system and the refrigerant temperature control device in a second embodiment.

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment is an example for explaining the present invention, and for clarity of explanation, appropriate omissions and simplifications have been made. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0015] The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings. When there are multiple components having the same or similar functions, they may be described using the same reference numeral with different subscripts. Furthermore, when it is not necessary to distinguish between these multiple components, the subscripts may be omitted in the description.

[0016] In some embodiments, processing performed by executing a program will be described. Here, a computer executes the program using a processor (e.g., a CPU or a GPU) and performs processing defined by the program using storage resources (e.g., memory) and interface devices (e.g., communication ports). Therefore, the entity that executes the program and performs the processing may be the processor. Similarly, the entity that executes the program and performs the processing may be a controller, device, system, computer, or node that has a processor.

[0017] The processing performed by executing the program may be performed by a computing unit, and may include a dedicated circuit for performing specific processing. Here, the dedicated circuit is, for example, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or a complex programmable logic device (CPLD).

[0018] A program may be installed on a computer from a program source. The program source may be, for example, a program distribution server or a computer-readable storage medium. When the program source is a program distribution server, the program distribution server may include a processor and storage resources for storing the program to be distributed, and the processor of the program distribution server may distribute the program to be distributed to other computers. In addition, in an embodiment, two or more programs may be realized as one program, or one program may be realized as two or more programs.

[0019] The cooling system in the first embodiment employs a water-cooling method, and uses water as a refrigerant to cool CPUs, GPUs, and the like (hereinafter referred to as processing devices) mounted on electronic devices such as computers and servers installed in a data center. The cooling system also controls the temperature by cooling the heat-generating processing devices so that the temperature of the water heated by the transfer of heat from the processing devices is, for example, approximately 80°C to 100°C, which is the maximum rated junction temperature of the processing devices. An example of such a cooling system will be described in detail below.

[0020] FIG. 1 is a diagram showing an example of the configuration of a cooling system according to a first embodiment. In FIG. 1, the cooling system 1 includes a refrigerant temperature control device 10, multiple variable valves (variable valves 21-26), multiple input temperature sensors (temperature sensors 31-36), multiple output temperature sensors (temperature sensors 41-46), multiple water channel switches (water channel switches 51-53), and multiple pumps (pumps 61 and 62). In FIG. 1, solid lines indicate piping (water channels) through which the refrigerant flows, and dotted lines indicate wiring used by the refrigerant temperature control device 10 to control the various components.

[0021] 2 is a diagram showing an example of the configuration of an electronic device to be cooled in the first embodiment. In Fig. 2, the electronic device 2 is composed of a computational load distributor 71 and multiple processing devices 91 to 96, each of which is provided with a heat sink 81 to 86 for dissipating generated heat into a refrigerant. In Fig. 2, the dashed lines indicate wiring through which the computational load distributor 71 distributes computational loads to each processing device and issues instructions to start execution of computations.

[0022] FIG. 3 is a configuration diagram showing the cooling system 1 installed relative to the electronic device 2. In FIG. 3, the dotted double-arrowed line indicates the wiring for bidirectional communication between the refrigerant temperature control device 10 and the computational load distributor 71. Note that in FIGS. 1 to 3, the electronic device 2 is equipped with six processing devices 91-96, and the cooling system 1 is configured to cool the six processing devices 91-96, including six variable valves 21-26, input temperature sensors 31-36, output temperature sensors 41-46, three water path switches 51-53, and two pumps 61 and 62. However, the number of each component is not limited to these, and the cooling system 1 may be configured to cool even more processing devices. Furthermore, the number of processing devices installed in one electronic device 2 is not limited to six, and may be more or less than six. For example, the processing devices 91-96 may be installed in two or more electronic devices 2.

[0023] 1 and 3 , the refrigerant temperature control device 10 detects the refrigerant temperatures measured by input-side temperature sensors 31-36 and output-side temperature sensors 41-46, as described below, and adjusts the aperture of variable valves 21-26 according to the respective refrigerant temperatures. It also controls the switching of water paths by water path switches 51-53 and the operation and stop of pumps 61 and 62. Variable valves 21-26 are provided for each processing device to be cooled, and adjust the amount of refrigerant input to heat sinks 81-86. Input-side temperature sensors 31-36 and output-side temperature sensors 41-46 are also provided for each processing device. The input-side temperature sensors 31-36 measure the temperature of the refrigerant input to the heat sinks 81-86, and the output-side temperature sensors 41-46 measure the temperature of the refrigerant output from the heat sinks 81-86. The refrigerant is in the form of cooling water when sent from the pumps 61 and 62 to the water paths. Meanwhile, the processing devices 91-96 generate heat according to the amount of calculation load distributed by the calculation load distributor 71, and the heat is dissipated to the refrigerant via the heat sinks 81-86. Therefore, the refrigerant is in a state that can be described as hot water when it is output from the heat sinks 81-86. Note that, in the examples shown in Figures 1 and 3, the variable valves 21-26 are arranged closer to the processing devices 91-96 than the input-side temperature sensors 31-36, but the order of arrangement is not critical, and the input-side temperature sensors 31-36 may be arranged closer to the processing devices 91-96 than the variable valves 21-26.

[0024] 1 and 3, pumps 61 and 62 are provided upstream of the input water channels for each of the three treatment devices, with one pump for each of the three treatment devices. The pumps are capable of sending refrigerant to the input water channels for each of the three treatment devices via water channel switches 51 and 52. In the example shown in FIGS. 1 and 3, water channel switches 51 to 53 can switch between the input water channels for each of the three treatment devices and the output water channels for the other three treatment devices according to several patterns. For example, when both pumps 61 and 62 are operating, water channel switches 51 and 52 connect each pump to a water channel so that the refrigerant sent from each pump flows into the input water channels for the treatment devices 91 to 93 and the treatment devices 94 to 96, respectively. When the pump 62 is stopped, the water channel switches 51 and 52 switch the water channels so that the coolant sent from the pump 61 also flows into the input water channels for the processing devices 94 to 96 (disconnecting the pump 62 and connecting the pump 61 to the input water channels for the processing devices 91 to 93 and the processing devices 94 to 96). Furthermore, the water channel switches 51 and 52 can also switch the water channels so that the coolant output from the heat sinks 81 to 83 flows directly into the input water channels for the processing devices 94 to 96 (disconnecting the pump 62 and connecting the output water channels for the processing devices 91 to 93 and the input water channels for the processing devices 94 to 96).

[0025] FIG. 4 is a diagram showing an example of the configuration of a refrigerant temperature control device 10 according to the first embodiment. In FIG. 4, the refrigerant temperature control device 10 includes a control unit 11, a valve adjustment unit 12, a temperature detection unit 13, a water channel switching unit 14, and a pump switching unit 15. The control unit 11 controls the overall operation of the refrigerant temperature control device 10 and communicates with a calculation load distributor 71 in the electronic device 2. The valve adjustment unit 12 adjusts the opening degrees of the variable valves 21-26. The temperature detection unit 13 detects the temperatures measured by the input-side temperature sensors 31-36 and the output-side temperature sensors 41-46. The water channel switching unit 14 controls the switching of the water channels by the water channel switches 51-53. The pump switching unit 15 controls the operation and stopping of the pumps 61 and 62.

[0026] Fig. 5 is a diagram showing an example of a refrigerant temperature control processing procedure performed by the cooling system 1 and the refrigerant temperature control device 10. Fig. 6 is a diagram showing an example of a processing procedure for calculation execution processing performed by the calculation load distributor 71 in the electronic device 2. As will be described below, the refrigerant temperature control device 10 communicates with the calculation load distributor 71, and they control the refrigerant temperature while each other advances processing.

[0027] First, in S201 in FIG. 6 , the computation load distributor 71 accepts a computation execution request from a user of the electronic device 2 (for example, a user outside the data center if the electronic device 2 is installed in a server room of the data center). The computation load distributor 71 transmits a notification of receipt of the computation execution request to the refrigerant temperature control device 10. Next, in S101 in FIG. 5 , the control unit 11 of the refrigerant temperature control device 10 receives the notification of receipt from the computation load distributor 71. In S102, the temperature detection unit 13 detects the refrigerant input / output temperatures for each processing device measured by the input-side temperature sensors 31-36 and the output-side temperature sensors 41-46, respectively. The control unit 11 transmits the refrigerant input / output temperatures (detection results) detected by the temperature detection unit 13 to the computation load distributor 71.

[0028] 6, in S202, the calculation load distributor 71 receives the detection results (refrigerant input / output temperatures for each processing device). Then, in S203, the calculation load distributor 71 calculates the amount of calculation load to be distributed to each processing device (the amount of calculation load for each processing device) based on the received refrigerant input / output temperatures. The calculation load distributor 71 transmits the calculation result to the refrigerant temperature control device 10. In FIG. 5, in S103, the control unit 11 receives the calculation result from the calculation load distributor 71. Next, in S104, the valve adjustment unit 12 individually adjusts the opening degrees of the variable valves 21 to 26 based on the received calculation result of the amount of calculation load for each processing device.

[0029] As described above, the cooling system of this embodiment controls the refrigerant output temperature (refrigerant output temperature) to, for example, approximately 80°C to 100°C, which is the maximum rated junction temperature of the processing device. Therefore, the apertures of the variable valves 21 to 26 are adjusted to an aperture that is estimated to result in a refrigerant output temperature of approximately 80°C to 100°C for each processing device, depending on the computational load of each processing device. Figures 7A and 7B show the relationship between the computational load of each processing device and the variable valve aperture. Figure 7A shows the proportional relationship between the computational load of the processing device and the variable valve aperture at which the junction temperature does not exceed the maximum value and the refrigerant output temperature is approximately 80°C, as well as the control range of the variable valve aperture. The valve adjustment unit 12 determines the aperture of the variable valves 21 to 26 depending on the computational load of each processing device, and can safely adjust the aperture within the control range shown in Figure 7A. The valve adjustment unit 12 may calculate the opening degrees of the variable valves 21 to 26 each time based on the calculation results of the calculation load amount of each processing device, using the proportional equation of the graph as shown in Figure 7A, or may store the opening degrees of the variable valves corresponding to the calculation load amount of the processing device in a memory within the refrigerant temperature control device 10 (not shown), and read out the opening degrees of the variable valves 21 to 26 corresponding to the calculation results of the calculation load amount of each processing device from the memory.

[0030] 5, when valve adjuster 12 completes adjusting the openings of variable valves 21 to 26 in S104, controller 11 transmits a completion notification to calculation load distributor 71. In FIG. 6, when calculation load distributor 71 receives a completion notification from refrigerant temperature control device 10 in S204, it instructs each processing device to start calculation execution in S205. As a result, each processing device executes calculations according to the amount of calculation load distributed to it.

[0031] Meanwhile, in FIG. 5 , in S105, the temperature detection unit 13 detects the refrigerant output temperature measured by the output-side temperature sensors 41-46 for each processing device after each processing device starts (during) its calculation. In S106, the control unit 11 determines whether the refrigerant output temperature for each processing device has exceeded the specified temperature, with 80°C being the specified temperature. For example, if the control unit 11 determines that the refrigerant output temperature for all processing devices 91-96 has exceeded the specified temperature, in S107, the control unit 11 transmits the determination result to the calculation load distributor 71. In FIG. 6 , upon receiving the determination result in S207, the calculation load distributor 71 thereafter repeats the processing from S201 onward in FIG. 6 to maintain the calculation load of each processing device (thereby maintaining the temperature or heat generation of each processing device). Similarly, the refrigerant temperature control device 10 also repeats the processing from S101 onward to maintain the refrigerant output temperature for each processing device.

[0032] If the control unit 11 determines in S106 that the refrigerant output temperature has not reached the specified temperature for some or all of the processing devices, the valve adjustment unit 12 readjusts the opening of the variable valve for the processing device whose refrigerant output temperature has not reached the specified temperature (temperature-unreached processing device) in S108. For example, if processing devices 91 and 93 are determined to be temperature-unreached processing devices, the valve adjustment unit 12 readjusts the opening of the variable valves 21 and 23. Increasing the opening of the variable valve increases the amount of refrigerant input, which results in greater cooling of the processing device, but makes it more difficult for the refrigerant output temperature to increase. On the other hand, decreasing the opening of the variable valve reduces the amount of refrigerant input, which increases the refrigerant output temperature. Therefore, the valve adjustment unit 12 readjusts the opening of the variable valve corresponding to the temperature-unreached processing device to decrease.

[0033] 7B , if the variable valve is initially adjusted to aperture A, which is assumed to result in a refrigerant output temperature of approximately 80° C. for a computational load X of the temperature non-attainment processing device, and the detected refrigerant output temperature is 70° C., the variable valve aperture is readjusted to aperture B, which is smaller than aperture A, so that the refrigerant output temperature rises by approximately 10° C. (The variable valve is closed to aperture B.) The variable valve aperture during readjustment may be calculated by the valve adjuster 12 according to the difference between the refrigerant output temperature and the specified temperature or the ratio between the refrigerant output temperature and the specified temperature, so as to move along the proportional graph shown in FIG. 7B within a range that does not exceed the maximum junction temperature. Alternatively, the valve adjuster 12 may repeat the process of readjusting the aperture (i.e., the process from S105 onward) for each smallest unit of aperture controllable by the valve adjuster 12 (e.g., 0.1 degrees).

[0034] However, because closing the variable valve, i.e., preventing the input of refrigerant while the processing device is operating (performing calculations), is not possible from the perspective of stable operation of the processing device, a minimum opening is predetermined as the specified opening. Therefore, in S109, the valve adjustment unit 12 determines whether the readjusted opening is not less than the specified opening. If the readjusted opening is not less than the specified opening, the processing procedures from S105 onwards are repeated for the temperature-unreached processing device until the refrigerant output temperature exceeds the specified temperature.

[0035] If the control unit 11 determines in S109 that the readjusted opening degree by the valve adjustment unit 12 is less than the specified opening degree, the readjustment of the variable valve opening degree will not cause the refrigerant output temperature to reach the specified temperature, and therefore in S110 the control unit 11 transmits a request to the calculation load distributor 71 to recalculate the calculation load amount of the temperature non-attainment processing device. In FIG. 6 , upon receiving a request to recalculate the calculation load amount of the temperature non-attainment processing device from the refrigerant temperature control device 10 in S206, the calculation load distributor 71 recalculates the calculation load amount to be distributed to the temperature non-attainment processing device in S208 and transmits the calculation result to the refrigerant temperature control device 10. Thereafter, the refrigerant temperature control device 10 repeats the processing procedure from S103 onward in FIG. 5 , and the calculation load distributor 71 repeats the processing procedure from S204 onward in FIG. 6 .

[0036] In S208, if only a few (e.g., one) of the processing devices have not yet reached the temperature, the computational load distributor 71 may recalculate only the computational load to be distributed to that processing device, or may recalculate the computational load by combining it with other processing devices with a large computational load. On the other hand, if many or all of the processing devices are not yet reached the temperature, the computational load distributor 71 recalculates the computational load to be distributed to all processing devices. In this case, if the total computational load of each processing device is small, the computational load may be recalculated to distribute to only some of the processing devices. For example, the computational load may be calculated to be distributed only to processing devices 91-93, and not to processing devices 94-96. When such a calculation result is received in S103, the water channel switch unit 14 controls the water channel switch unit 52 to disconnect the water channels connected to processing devices 94-96, and the pump switch unit 15 may stop the pump 62, before adjusting the opening degree of the variable valve in S104. By doing so, a sufficient amount of calculation load is distributed to some of the processing devices, making it possible to increase the coolant output temperature.

[0037] The above description of the refrigerant temperature control process shown in Figure 5 primarily describes an example in which the valve adjuster 12 adjusts the opening of each variable valve to control the refrigerant output temperature to exceed a specified temperature. However, the refrigerant temperature control device 10 can also control the refrigerant output temperature to increase by switching the water channels in addition to adjusting the opening of each variable valve. Specifically, the refrigerant temperature control device 10 executes the process shown in Figure 5 from S101 to S109. Before executing S110, the water channel switcher 14 controls the water channel switcher 52 to switch the water channel so that the refrigerant output from the heat sinks 81 to 83 flows directly to the input water channel for the processing devices 94 to 96. (In this case, the pump switcher 15 also stops the pump 62.) In this way, the refrigerant that has cooled the processing devices 91 to 93 and been converted into warm water but has not yet reached the specified temperature is further warmed by cooling the processing devices 94 to 96 via the heat sinks 84 to 86, thereby increasing the refrigerant output temperature. After the water path switching process by the water path switching unit 14, the refrigerant temperature control device 10 re-executes the processes from S105 onwards. If the refrigerant output temperature exceeds a specified temperature due to the recirculation of the refrigerant to other processing devices after cooling the processing device, the control unit 11 executes S107. If the refrigerant output temperature does not yet exceed the specified temperature, the recirculation to other processing devices may be repeated. Note that the water path switching process is not limited to being executed after S109, but may be executed before, after, or in parallel with S108.

[0038] As described above, the cooling system of the first embodiment precisely adjusts the opening of the variable valve provided for each processing device in accordance with the refrigerant input / output temperatures and the computational load of each processing device, thereby increasing or decreasing the amount of refrigerant input to each processing device and controlling the refrigerant output temperature to a specified temperature. Furthermore, by communicating with electronic devices, the cooling system can appropriately increase or decrease the computational load distributed to each processing device, thereby controlling the refrigerant output temperature. Furthermore, by recirculating the refrigerant that has cooled a processing device to another processing device as needed, the cooling system can be controlled to further increase the refrigerant output temperature in conjunction with the adjustment of the variable valve opening.

[0039] In cooling systems used in data centers, not only cooling performance for electronic devices but also energy-saving performance is important. Therefore, in the second embodiment, an example of a cooling system capable of suppressing energy consumption will be described. Note that the configurations of the cooling system, the electronic devices to be cooled, and the refrigerant temperature control device in the second embodiment are the same as those shown in Figures 1 to 4. The calculation execution processing procedure in the electronic devices is also the same as that shown in Figure 6. In the following explanation, explanations of content that overlaps with the first embodiment will be omitted, and differences will be explained.

[0040] Figure 8 is a diagram showing an example of a refrigerant temperature control process procedure performed by the cooling system 1 and the refrigerant temperature control device 10 in the second embodiment. In Figure 8, steps S301 to S307 and steps S309 to S311 are the same as steps S101 to S107 and steps S108 to S110 shown in Figure 5. The process procedure shown in Figure 8 differs from the process procedure shown in Figure 1 in that steps S308 and S312 have been newly added.

[0041] Similar to the processing procedure shown in FIG. 5 , the refrigerant temperature control device 10 executes steps S301 to S306. If the control unit 11 determines in S306 that the refrigerant output temperatures of some or all of the processing devices have not reached the specified temperature, the control unit 11 calculates the energy consumption of the entire cooling system at that time and determines whether it exceeds a predetermined target value for energy consumption in S308. The control unit 11 monitors the operating status, operating time, and power consumption of all components in the cooling system, namely, the refrigerant temperature control device 10, the variable valves 21-26, the input-side temperature sensors 31-36, the output-side temperature sensors 41-46, the water path switches 51-53, and the pumps 61 and 62, and calculates the energy consumption based on these. The target value can be set to any value in advance, and may be a target value unique to the cooling system or, if used in a data center, a target value determined as part of the target value for the entire data center. Furthermore, the target value need not be a fixed value, but may be a value that varies depending on, for example, the energy consumption of the entire data center.

[0042] If the control unit 11 determines in S308 that the energy consumption of the cooling system does not exceed the target value, the refrigerant temperature control device 10 executes the processes from S309 onward. On the other hand, if the control unit 11 determines in S308 that the energy consumption of the cooling system exceeds the target value, the process proceeds to S312, in which the water channel switching unit 14 and the pump switching unit 15 execute pump / water channel switching control to reduce the energy consumption of the cooling system. When the cooling system starts up, all pumps are operated, and each pump is connected to a water channel so that the refrigerant sent from each pump flows into the input water channel for each processing device. Therefore, in the pump / water channel switching control, if all pumps are operating at that time, the pump switching unit 15 stops some of the pumps, such as pump 62. In response to the stopping of pump 62, the water channel switching unit 14 controls the water channel switcher 52 to switch the water channel so that the refrigerant sent from pump 61 also flows into the input water channels for processing devices 94-96.

[0043] In the configuration example of Figure 3, only pumps 61 and 62 and water channel switchers 51 to 53 are shown, but the cooling system may have more pumps and water channel switchers depending on the number of processing devices, so depending on the degree to which the energy consumption exceeds the target value, the pump switcher 15 stops one or more pumps, and the water channel switcher 14 controls one or more water channel switchers to switch the water channels.

[0044] In this way, by controlling the operation and stopping of the pump and the corresponding switching of the water channels, it is possible to reduce the energy consumption of the cooling system as needed. Note that when the pump / water channel switching control of S312 is executed, the refrigerant input / output temperatures for each processing device may change, so the refrigerant temperature control device 10 returns to S302 and repeats the subsequent processes.

[0045] As described above, according to the cooling system of the second embodiment, in addition to the same effects as those of the first embodiment, it is possible to reduce the energy consumption of the cooling system and operate the cooling system in an energy-saving manner.

[0046] Although the above describes various embodiments and variations of the present invention, the present invention is not limited to the above-described exemplary embodiments and includes various variations. For example, the above-described exemplary embodiments have been described in detail to facilitate understanding of the present invention, and the present invention is not limited to those including all of the components described herein. Furthermore, it is possible to replace part of the components of one exemplary embodiment with the components of another exemplary embodiment. It is also possible to add the components of another exemplary embodiment to the components of one exemplary embodiment. Furthermore, it is also possible to add, delete, or replace part of the components of each exemplary embodiment with other components. Furthermore, some or all of the above-described components, functions, processing units, processing means, etc. may be implemented in hardware, for example, by designing them as integrated circuits. Furthermore, the control lines and information lines in the figures are those considered necessary for explanation, and are not necessarily all shown. It is also possible to consider that almost all components are interconnected.

[0047] REFERENCE SIGNS LIST 1... Cooling system 2... Electronic device 10... Refrigerant temperature control device 11... Control unit 12... Valve adjustment unit 13... Temperature detection unit 14... Water channel switching unit 15... Pump switching unit 21-26... Variable valves 31-36... Input side temperature sensors 41-46... Output side temperature sensors 51-53... Water channel switching devices 61, 62... Pumps 71... Computational load distributor 81-86... Heat sinks 91-96... Processing device

Claims

1. A cooling system for cooling electronic equipment, comprising: a plurality of processing devices; and a computational load distributor that calculates a computational load to be distributed to the plurality of processing devices and causes the plurality of processing devices to perform computations in accordance with the computational load, the cooling system comprising: a water channel for inputting and outputting a liquid cooling medium to and from a heat sink provided for each of the processing devices; a plurality of variable valves that are provided for each of the processing devices and adjust the amount of the cooling medium input to the heat sink; a plurality of input-side temperature sensors that are provided for each of the processing devices and measure the input temperature of the cooling medium input to the heat sink; a plurality of output-side temperature sensors that are provided for each of the processing devices and measure the output temperature of the cooling medium output from the heat sink; and a cooling medium temperature control device, wherein the cooling medium temperature control device comprises: a control unit that receives the computational load for each of the processing devices calculated by the computational load distributor; a temperature detection unit that detects the input temperature and output temperature of the cooling medium for each of the processing devices measured by the plurality of input-side temperature sensors and the plurality of output-side temperature sensors; and a valve adjustment unit that individually adjusts the opening of the plurality of variable valves in accordance with the computational load for each of the processing devices and at least the output temperature of the cooling medium.

2. A cooling system according to claim 1, wherein the control unit determines whether the output temperature exceeds a predetermined temperature for each of the processing devices, and when it determines that the output temperature for one or more of the processing devices does not exceed the predetermined temperature, the valve adjustment unit individually readjusts the opening of one or more of the variable valves provided for each of the one or more processing devices to reduce the opening.

3. A cooling system according to claim 1, wherein the valve adjustment unit adjusts the opening of the plurality of variable valves individually in accordance with the amount of calculation load for each processing device and the input and output temperatures of the cooling medium before each processing device starts to execute a calculation, and the control unit determines whether the output temperature for each processing device exceeds a predetermined temperature after each processing device starts to execute a calculation.

4. A cooling system as claimed in claim 2, further comprising a plurality of pumps that send the cooling medium to the water channels, and a plurality of water channel switchers that switch the connection between each of the pumps and the water channels, wherein the cooling medium temperature control device further comprises a pump switcher that controls the operation or stop of each of the pumps, and a water channel switcher that controls the switching of the water channels by each of the water channel switchers.

5. A cooling system as claimed in claim 4, wherein the pump switching unit stops one or more of the pumps in accordance with the amount of calculation load for each of the processing devices or in accordance with the result of the judgment by the control unit, and in accordance with the stopping of the one or more pumps, the water channel switching unit controls one or more of the water channel switches to switch the connection between the one or more pumps and the water channels.

6. A cooling system as claimed in claim 4, wherein, when the control unit determines that the output temperature for the one or more processing devices does not exceed the predetermined temperature, the water channel switching unit controls one or more of the water channel switches to switch the connection of the water channels so that the cooling medium output from the heat sink provided for each of the one or more processing devices is input to the heat sink provided for each of the other one or more processing devices.

7. A cooling system as claimed in claim 4, wherein the control unit determines whether the energy consumption of the entire cooling system exceeds a predetermined value, and if it determines that the energy consumption exceeds the predetermined value, the pump switching unit stops one or more of the pumps, and in response to the stopping of the one or more pumps, the water channel switching unit controls one or more of the water channel switches to switch the connection between the one or more pumps and the water channels.

8. A cooling method for an electronic device comprising a plurality of processing devices and a calculation load distributor that calculates the amount of calculation load to be distributed to the plurality of processing devices and causes the plurality of processing devices to execute calculations in accordance with the amount of calculation load, the cooling method comprising: measuring an input temperature of a liquid cooling medium input to each heat sink provided for each of the processing devices and an output temperature of the cooling medium output from each of the heat sinks; notifying the calculation load distributor of the input temperature and the output temperature; receiving the calculation load amount for each of the processing devices calculated based on the input temperature and the output temperature; and individually adjusting the amount of the cooling medium input to each of the heat sinks in accordance with the calculation load amount for each of the processing devices and at least the output temperature.

9. A cooling method according to claim 8, comprising measuring the output temperature of the cooling medium during the operation of each of the processing devices, determining whether the output temperature exceeds a predetermined temperature for each of the processing devices, and, if it is determined that the output temperature for one or more of the processing devices does not exceed the predetermined temperature, individually readjusting the input amount of the cooling medium to each of the heat sinks to reduce it for each of the one or more processing devices.

10. A cooling method according to claim 8, wherein in the step of individually adjusting the input amount of the cooling medium to each heat sink, the input amount of the cooling medium to each heat sink is individually adjusted in accordance with the calculation load amount for each processing device and the input temperature and output temperature of the cooling medium before each processing device starts executing calculations.

11. A cooling method according to claim 9, wherein, when it is determined that the output temperature for said one or more processing devices does not exceed said predetermined temperature, the cooling medium output from each of said heat sinks provided for said one or more processing devices is input to each of said heat sinks provided for one or more other of said processing devices.

12. A cooling method according to claim 9, wherein the connection between a plurality of pumps that send the cooling medium to each heat sink and a water channel through which the cooling medium flows is switched depending on the amount of calculation load for each processing device or the result of the judgment.

13. A cooling method according to claim 12, comprising determining whether the energy consumption for cooling the electronic device exceeds a predetermined value, stopping one or more of the plurality of pumps when it is determined that the energy consumption exceeds the predetermined value, and switching the connection between the one or more pumps and the water channel in response to the stopping of the one or more pumps.

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