Patent Application
20230023287
The present invention relates to a cooling system, a cooling method and program.
Along with the progress made in cloud services or the like, to handle explosive data traffic, the accommodation of data centers has been increased. Accordingly, technologies for cooling server systems at the data centers with high-efficiency are demanded.
Patent Literature 1 (WO2017/199444) discloses a system having a centrifugal blower and a heat exchanger. The centrifugal blower to be accommodated in a housing having an air inlet includes a spiral casing having a bell mouth and a centrifugal fan housed in the casing. The heat exchanger is disposed in an air flow path inside the housing.
The system disclosed in the prior art utilizes fans to move air across a heat exchanger. However, since a cooling capacity of the heat exchanger is not always constant at a rated cooling capacity, an unutilized portion in the heat exchanger still remains in the case of two-phase heat transfer applications. Therefore, there is room for achieving an improvement in the efficiency of heat transferring.
An example object of the present disclosure is to solve one of the above-described problems.
An aspect of the present invention is a cooling system for cooling a server module. The system has a housing, a heat exchanger and an air distribution controller. The housing including an inlet configured to receive air exhausted from the server module and an outlet configured to provide air to the server module. The heat exchanger is mounted between the inlet and the outlet, the heat exchanger is configured so that a refrigerant contained in the heat exchanger exchanges heat with air passing through the heat exchanger, wherein the heat exchanger accepts variation of the refrigerant liquid level. The air distribution controller is mounted in an inlet side of the heat exchanger. The air distribution controller has at least one movable plate which allows an airflow profile from the inlet to the heat exchanger to be redirected. The air distribution controller controls the airflow profile depending on the liquid level.
An aspect of the present invention is a cooling method for a cooling system. The cooling system includes a heat exchanger containing a refrigerant and an air distribution controller. The cooling method includes an acquiring a cooling capacity step, a liquid level estimation step and an air distribution control step. The acquiring the cooling capacity step is a step in which the cooling capacity of the heat exchanger is calculated based on a temperature at a predetermined point of the cooling system. The liquid level estimation step is a step in which the liquid level of the heat exchanger is estimated based upon the cooling capacity. The air distribution control step is a step in which the air distribution controller redirects the airflow profile depending upon the liquid level.
An aspect of the present invention is a non-transitory computer readable medium storing a program for causing a computer to execute a cooling method for a cooling system. The cooling system includes a heat exchanger containing a refrigerant and an air distribution controller. The cooling method includes an acquiring a cooling capacity step, a liquid level estimation step and an air distribution control step. The acquiring the cooling capacity step is a step in which the cooling capacity of the heat exchanger is calculated based on a temperature at a predetermined point of the cooling system. The liquid level estimation step is a step in which the liquid level of the heat exchanger is estimated based upon the cooling capacity. The air distribution control step is a step in which the air distribution controller redirects the airflow profile depending upon the liquid level.
According to the present invention, it is possible to provide a cooling system and the like which can implement heat transfer with high efficiency.
Example embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and thus repeated descriptions are omitted as needed.
Hereinafter, with reference to the drawings, example embodiments of the present disclosure will be explained.
The cooling system 100 shown in
The housing 101 is a console which houses components of the cooling system 100. The housing 101 may have a structure for mounting it on equipment in which a data center or the like is installed. The housing 101 includes an inlet 102 and outlet 103. The inlet 102 has an opening for receiving air exhausted from the server module into the housing 101. The outlet 103 has an opening for providing air from inside the housing 101 to the server module. As shown in
The heat exchanger 110 is mounted between the inlet 102 and the outlet 103 in the housing 101. As shown in
The refrigerant 111 in the heat exchanger 110 exists as a liquid 111L or a vapor 111V. Further the liquid level of the refrigerant varies when the supply quantity from a means which supplies the liquid changes the quantity level. Note that, in this case, the liquid level refers to a position level of the liquid surface 111S in the refrigerant 111. That is, the heat exchanger 110 accepts variation of the refrigerant liquid level.
The structure of the heat exchanger 110 may be that of a typical heat exchanger such that the heat exchanger 110 has multiple tubes containing the liquid refrigerant and fins. Further, the heat exchanger 110 has multiple through holes or paths so that the air from the inlet 102 contacts the fins surface and passes to the outlet 103. The heat exchanger 110 is configured to extract thermal energy from air and transfer the thermal energy to the liquid refrigerant. Transferring the thermal energy from air to the liquid refrigerant results in the liquid being evaporate into a vapor. The heat exchanger 110 may be connected to a circulation system which allows the vapor to be captured from the heat exchanger 110 and liquid to be supplied thereto. Accordingly, the cooling system 100 may be configured for a vapor-compression refrigeration system or phase change cooling system. In other words, the cooling system 100 may be a part of such system.
The air distribution controller 120 is mounted in the inlet side of the heat exchanger 110. As shown in
In
The air distribution controller 120 can redirect the airflow when it is rotated and fixed in another position. The air distribution controller 120 may be rotated by a mean to drive the air distribution controller 120 such as a motor or an actuator. The air distribution controller 120 may also be rotated by a user. The position of the air distribution controller 120 may be fixed depending on the liquid level of the refrigerant 111.
Next, another state in which the air distribution controller 120 redirects the airflow will be described in
Another difference between
The air distribution controller 120 redirects the air from the right part to the left part. As a result, for example, in this case, air received at the right part of the inlet 102 passes at the middle part of the heat exchanger 110 and is exhausted at the upper part of the outlet 103.
Although the first example embodiment has been described above, the configuration according to the first example embodiment is not limited to the above-described configuration. The air distribution controller 120 may include a plurality of plates for redirecting the airflow profile. The outline of the housing 101 is not limited to the shape above mentioned. An arbitrary shape may be adopted as the outline of the housing 101.
As mentioned above, the cooling system 100 can redirect the airflow passing through the heat exchanger 110 depending upon the liquid level. More concretely, the cooling system 100 can redirect the airflow profile passing through the heat exchanger 110 so that the airflow passes through the portion in where the heat exchanger 110 contains the liquid refrigerant. Hence, the cooling system 100 improves an efficiency of the heat transfer. As described above, according to the first example embodiment, it is possible to provide a cooling system and the like which can implement heat transfer with high efficiency.
Hereinafter, second example embodiment will be described.
The main building 500 is configured to circulate air from server module 400 to the cooling system 200 and from the cooling system 200 to the server module 400. In the circulation system, the airflow from the server module 400 to the cooling system 200 is called “hot aisle”, while the airflow from the cooling system 200 to the server module 400 is called “cold aisle”. The cooling system 200 receives air exhausted from server module 400 via the hot aisle. Further, the cooling system 200 exhausts air, by which is absorbed heat, to the cold aisle and the air is provided to the server module 400. Then the server module 400 exhausts the air heated by the server module 400 to the hot aisle again. Note that such system shown in
The fan unit 220 is attached to the inlet of the cooling system 200. The fan unit 220 includes a fan motor to pump the air in the hot aisle to the cooling system 200. The server module 400 is composed of, for example, a server rack which can house at least one server computer. The server module 400 is configured to establish a pathway to receive the air from the cold aisle and to exhaust the air heated by the server computer to the hot aisle.
The cooling system 200 is configured to receive the air from the server module via the cold aisle and the fan unit 220, absorb the heat from the air by refrigerant contained in a heat exchanger 110 and exhaust the air which the heat has been absorbed to the cold aisle. The cooling system 200 includes an air distribution controller 210. The air distribution controller 210 in the present embodiment has a plural of plates to redirect the airflow profile. Note that the detail of the cooling system 200 will be described later.
The cooling system 200 and the outdoor unit 250 are connected each other by a first pipe 241 and a second pipe 242 so as to circulate the refrigerant among them. The first pipe 241 transfers a refrigerant which has absorbed the heat from the air in the heat exchanger 110. In the middle of the first pipe 241, the first pipe 241 has a compressor 230. The compressor 230 compresses the vapor evaporated in the heat exchanger 110 by absorbing the heat from the air which passes the heat exchanger 110. The outdoor unit 250 is configured to receive the compressed refrigerant, reject the heat from the refrigerant, condense refrigerant so as to the refrigerant becomes a liquid and pump the liquid refrigerant which the heat has been rejected to the cooling system 200 via the second pipe 242. In the middle of the second pipe 242, the second pipe 242 has a valve unit 260. The valve unit 260 is configured to control a supply quantity of liquid refrigerant to the heat exchanger 110 in the cooling system 200.
The cooling system 200 and other components connected to the cooling system 200 may be controlled by a control unit having arithmetic and logic unit such as CPU (Central Processing Unit) or MCU (Micro Controller Unit). Accordingly, operation of the cooling system 200, the fan unit 220, the compressor 230, the outdoor unit 250 and the valve unit 260 may be correlated or integrated.
The louver unit 210 is one aspect of the air distribution controller. The louver unit 210 is attached to the housing 201. The louver unit 210 has the inlet 102 to receive the air from the fan unit 220. Since the louver unit 201 is connected to the housing 201 so that the air flows successively, the housing 201 and the console of the louver unit 210 may be referred as housing. Therefore, it may be described that the housing 201 has the inlet 102.
The louver unit 210 has 6 louvers 211 (louver 211A to 211F). The louvers 211 are aligned along X-direction. Each louver 211 is formed in a flat rectangle plate and has an axis 212 at the middle of the plate in Y-direction so that it can rotate about the axis 212. The louvers 211 are driven by motors (not shown).
The direction of the louvers 211A to 211D shown in
The temperature sensor 213 detects a temperature of a point where the temperature sensor 213 is attached. The temperature sensor 213 is attached to a predetermined position such as the center part of the outlet 103 of the cooling system to monitor the air temperature. The temperature sensor 213 is connected to a controller (not shown) and provides a temperature data to the controller.
The controller 270 is composed of a certain combination of electronic devices and circuit which includes arithmetic and logic unit such as CPU, or MCU. The controller 270 can perform predetermined process by such components and the program installed in the controller 270. In other words, the controller 270 can perform predetermined process by the hardware and the software. The controller 270 is connected each component and configured to receive data from them and provide command signals to them. More specifically, the controller 270 receives the temperature data from the temperature sensor 213 and calculates current cooling capacity of the cooling system by utilizing the temperature data.
The current cooling capacity may be calculated by a following equation (1) and (2):
Q=mr×ΔH (1);
ΔH=Hout−Hin (2);
where Q is amount of energy transfer (kW), mr is refrigerant mass flow rate (kg/s) and ΔH is difference in enthalpy (KJ/kg) of refrigerant which can be calculated by subtracting enthalpy at heat exchanger outlet Hout from enthalpy at heat exchanger inlet Hin. The enthalpy at heat exchanger inlet and outlet can be calculated by measuring two physical variables such as temperature and pressure at required location by appropriate sensors.
Note that the current cooling capacity may also be calculated by a following equation (3):
Q=ma×Cp×ΔTma=p×qΔT=Tout—Tin (3);
where Q is amount of energy transfer (kW), ma is the rate of airflow mass flowing through heat exchanger (kg/s) which can be calculated by multiply air density p (kg/m3) and airflow rate q (m3/s) which can be measured by standard airflow measurement device. Cp is specific heat at constant pressure (KJ/kg·k) and ΔT is difference in temperature (K) of air which can be calculated by subtracting temperature at heat exchanger outlet Tout from temperature at heat exchanger inlet Tin. The temperature at heat exchanger inlet and outlet can be calculated by measuring temperature via standard thermocouple.
Also, the controller 270 acquires a rated cooling capacity of the cooling system 200. The rated cooling capacity indicates the capacity of the heat exchanger 110 of the cooling system 200. The rated cooling capacity refers to the amount of heat transport (W) per temperature difference 1 (K) of the heat exchanger 110. Since the rated cooling capacity is a value determined by the characteristics of the cooling system 200, the rated cooling capacity may be memorized in the memory 280.
Further, the controller 270 calculates a ratio of the current cooling capacity to the rated cooling capacity. Note that for the sake of convenience, the ratio of the current cooling capacity to the rated cooling capacity is referred to “CR” or “CR value”. Furthermore, the controller 270 fetches open ratio information from the memory 280 and determines each angle of louver 211 by referring the open ratio information. The open ratio information is information which indicates the relation between the open ratio of the louvers 211 and CR. Note that the detail of the open ratio information will be described later. The controller 270 supplies an indication signal to the driver 290 to set the louver angle.
The controller 270 may have other function for controlling other correlated components mentioned above such as the outdoor unit 250, or the valve unit 260 and the like. The controller 270 may connected to other system which controls the above mentioned components.
The memory 280 includes a non-volatile memory such as flash memory to memorize a certain data. The memory 280 memorizes at least open ratio information. The memory 280 supplies the open ratio information and the like in response to the indication from the controller 270.
The driver 290 includes motor driver circuit and controls three motors M1, M2 and M3. The driver 290 receives an indication from the controller 270, drives motors in accordance with the indication from the controller 270. In this example embodiment, the driver 290 controls the motors M1, M2 and M3 separately. That is, the driver 290 may drive these motors in different angle, or different timing.
The motor M1 is configured to rotate the louver 211A and 211B. Accordingly, the louver 211A and 211B is rotated simultaneously. Likewise, the louver 211C and 211D is rotated simultaneously while the motor M2 is configured to rotate the louver 211C and 211D. The louver 211E and 211F is rotated simultaneously while the motor M3 is configured to rotate the louver 211E and 211F.
Next, how the louvers 211 are controlled by motors will be described by referring
As shown in
A line described by two-dot chain line indicates the louver 211 rotates in counter clock wise by angle L1. At this angle, it is defined that the open ratio is +0.25. In this case, the attached sign “+” is referred that the direction of its rotation is in counter clock wise. Further, the absolute value “0.25” indicates its angle between the lines at open ratio is 1 and 0.25.
A line described by dotted line indicates the louver 211 rotates in counter clock wise by angle L2 where the angle L2 is greater than the angle L1. At this angle, it is defined that the open ratio is +0.1. In this case, the attached sign “+” is referred that the direction of its rotation is in counter clock wise. Further, the absolute value “0.1” indicates its angle between the lines at open ratio is 1 and 0.1.
Next, the relation between the open ratio and CR will be described by referring
The CR value varies depending upon the current cooling capacity. The current cooling capacity is determined depending upon the temperature where the temperature sensor 213 is attached. Thus, shown in the
On contrast, when the temperature is relatively low, CR value becomes relatively low (i.e. CR<0.33). Accordingly, the liquid level becomes relatively low.
Next, process performed by the cooling system is described with reference to
Firstly, the controller 270 acquires rated cooling capacity C1 (Step S10). The controller 270 may acquire the rated cooling capacity C1 from a user, or other system.
The controller 270 then acquires current cooling capacity C2 (Step S11). The controller may acquire the current cooling capacity by receiving the temperature data from temperature sensor 213 and calculating above mentioned equation (1) and (2).
Further, the controller 270 calculates CR (Step S12). CR is calculated by dividing C1 to C2.
Next, the controller 270 fetches the open ratio information from memory 280 and determines the open ratio of motors M1, M2 and M3 (Step S13) by referring the CR and the open ratio information.
The controller 270 then indicates the driver 290 to set the motors M1, M2 and M3 in a determined open ratio (Step S14).
Next, the controller 270 determines whether to stop the series of process (step S15). For example, when the controller 270 detects the system powered off, the controller 270 determines to stop the series of process (step S15: Yes) and terminates the process. Meanwhile, if the controller 270 has determined not to stop the series of process (step S15: No), the controller 270 returns to step S11 and continues with the process.
By performing the above described process, it is possible that the cooling system 200 set airflow profile corresponding to the calculated liquid level.
Although the second example embodiment has been described above, the configuration according to the second example embodiment is not limited to the above-described configuration. For example, the fan unit 220 may be attached to the outlet 103 instead of the inlet 102 to pump the air exhausted from the cooling system 200 to the server module 400. The fan unit 220 may be attached to both the inlet 102 and the outlet 103. Also, composing the fan unit 220 is not mandatory. The number of the louvers and motors is not limited to above example. The louver unit 210 may have at least one louver. At least one motor is composed for the cooling system 200. The motor may control one or more louvers to be rotated. The cooling system 200 may have a mechanism which allows one motor to rotate a plural of louvers in different rotate ratio. The temperature sensor 220 may be attached to another point where the cooling system can acquire the current cooling capacity to control the refrigerant liquid level. The cooling system may have a plurality of temperature sensors. The cooling system may have a temperature sensor which can detect a temperature of the heat exchanger. By detecting the temperature of the heat exchanger, the cooling system can estimate the refrigerant liquid level.
As described above, it is possible to provide a cooling system and the like which can implement heat transfer with high efficiency.
Third example embodiment will be described with referred to
In the case shown in
In the case of this embodiment, the controller 270 can control the motor by referring the open ratio information similar to that in the case of the second example embodiment. Note that in this case, the open ratio may also be referred to aperture ratio, which refers to proportion of the opening of the inlet 102.
Note that the number of the sliders is not limited to the above configuration. The cooling system 300 may have at least one slider. The slider may have a telescopic motion mechanism. The slider may have characteristics such as flexibility or elasticity.
As described above, it is possible to provide a cooling system and the like which can implement heat transfer with high efficiency.
The program can be stored and provided to a computer using any type of non-transitory computer readable media. Non-transitory computer readable media include any type of tangible storage media. Examples of non-transitory computer readable media include magnetic storage media (such as floppy disks, magnetic tapes, hard disk drives, etc.), optical magnetic storage media (e.g. magneto-optical disks), CD-ROM (Read Only Memory), CD-R, CD-R/W, and semiconductor memories (such as mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory), etc.).
The program may be provided to a computer using any type of transitory computer readable media. Examples of transitory computer readable media include electric signals, optical signals, and electromagnetic waves. Transitory computer readable media can provide the program to a computer via a wired communication line, such as electric wires and optical fibers, or a wireless communication line.
While the present invention has been described above with reference to exemplary embodiments, the present invention is not limited to the above exemplary embodiments. The configuration and details of the present invention can be modified in various ways which can be understood by those skilled in the art within the scope of the invention.
The present invention is applicable to industries using data center including a server module, supercomputer, or mainframe computer system.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/001314 | 1/16/2020 | WO |
