Patent Application
20230309273
The present disclosure relates to a system, a method and a non-transitory computer readable storage medium for maintaining and improving airflow distribution uniformity at a heat exchanger surface in a compact size cooling system.
A local cooling system such as a modular cooling unit is placed near a rack air outlet. The local cooling system can operate at higher temperatures and a lower airflow, resulting in higher thermal efficiency. Usually, a space between a rack top surface and a ceiling is limited, and thus a theoretical height of the modular cooling unit is restricted to less than 1 m. In reality, some space is required for a coolant pipe and auxiliary equipment, such as a rack cable tray, and thus the height of the modular cooling unit is restricted to 0.5 m to 0.7 m.
In a cooling system, it is desired that a fan required for airflow generation be placed in a pull setting, i.e., pulling airflow from a heat exchanger, in order to generate a uniform airflow. However, in a pull setting, a space between a rack top surface and a ceiling is limited, and thus a fan size is reduced and hence airflow becomes smaller. In order to overcome this problem, since, in a push setting, a surface area larger than that of the above space in a pull setting is available below the heat exchanger, a fan larger than that which can be placed in the pull setting can be placed in the push setting, i.e. pushing airflow at a heat exchanger surface, and generating sufficient airflow.
[Non Patent Literature]
NPL 1: Green aisle by Toyo netsu kogyou kabushiki kaisha (https://www.tonets.co.jp/Portals/0/images/business/request/pdf/.pdf)
Placing a larger fan in a push setting can cause a higher airflow to be generated in a modular cooling unit. However, the generated airflow is non uniform at heat exchanger surface, thus resulting in poor thermal efficiency. This problem can be solved by increasing the distance between the fan and the heat exchanger to less than 6-7 times a fan depth, where the fan depth is less than 50 mm. However, for a compact modular cooling unit of less than 200 mm in height, maintaining a distance between the fan and the heat exchanger surface to less than less than 6-7 times a fan depth is not an option.
The present disclosure has been accomplished to solve the above problems and an object of the present disclosure is thus to provide a system, method and non-transitory computer readable storage medium capable of generating a uniform airflow at a heat exchanger surface.
A system according to a first exemplary aspect of the present disclosure includes
A method of tuning a fan operation according to a second exemplary aspect of the present disclosure includes: in a system including a cooling unit body having an airflow inlet and an airflow outlet; a heat exchanger provided inside the cooling unit body; and a plurality of fans provided at the airflow inlet, wherein the plurality of fans are configured to be connected to respective power lines and to be connected to respective signal lines, the method includes:
A non-transitory computer readable storage medium according to a third exemplary aspect of the present disclosure is a non-transitory computer readable storage medium storing instructions to cause a computer to perform the steps of:
According to the exemplary aspects of the present disclosure, it is possible to provide a system, method and non-transitory computer readable storage medium capable of generating a uniform airflow at a heat exchanger surface.
Hereinafter, specific embodiments to which the above-described example aspects of the present disclosure are applied will be described in detail with reference to the drawings. In the drawings, the same elements are denoted by the same reference signs, and repeated descriptions are omitted for clarity of the description.
Example embodiments are described herein with reference to block diagrams and/or flowchart illustrations of computer-implemented methods, apparatus (systems and/or devices) and/or computer program products. It is understood that a block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions that are performed by one or more computer circuits. These computer program instructions may be provided to a processor circuit of a general purpose computer circuit, special purpose computer circuit, and/or other programmable data processing circuit to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, transform and control transistors, values stored in memory locations, and other hardware components within such circuitry to implement the functions/acts specified in the block diagrams and/or flowchart block or blocks, and thereby create means (functionality) and/or structures for implementing the functions/acts specified in the block diagrams and/or flowchart block(s).
For achieving a higher airflow in compact and modular cooling units, a fan is placed in a push setting instead of a pull setting due to availability of an area, as utilized in NPL 1, larger than that available in a pull setting. However, the placement of such a fan will result in non-homogeneous airflow distribution at a heat exchanger surface and thus thermal efficiency is reduced.
In order to control airflow distribution at a heat exchanger surface in a compact and modular cooling unit, and in order to achieve higher thermal efficiency by generating homogeneous airflow, a plurality of fans are utilized in a push setting. Each fan operation point can be tuned to achieve more homogenous airflow distribution.
As shown in
As shown in
Since the plurality of fans 16 and 17 push airflow at the heat exchanger 12, the airflow distribution will be more homogeneous as compared to that in the case of a single large fan. At the same time, each individual fan 16, 17 can be controlled independently by independent signal line 161, 171 respectively. The fan duty tuning can be performed according to a flowchart of
With reference to
In
In Step S101, the controller 200 starts the individual fan duty tuning process. In Step S102, the control unit 200 initializes all fans with the identical fan duty. In
In Step S103, the controller 200 selects a fan for which tuning has not been performed. The fan duty tuning is performed for the selected fan. In
A set of air velocity sensors are placed at the heat exchanger 22 air inlet or outlet surface. In Step S104, the controller 200 selects a set of air velocity sensors corresponding to the fan selected in Step S103 out of the full set of air velocity sensors. As an example, an air velocity sensor 265 placed against the air outlet heat exchanger 22 surface is selected out of the full set of sensors (i.e. 265 and 275).
In Step S105, the controller 200 compares an air velocity of the selected air velocity sensor with that of the full set of air velocity sensors. As an example, the value of the sensor 265 is compared with the average of the full set of sensors (i.e. 265 and 275). In the case of three or more sensors, an average of values may be used. At the same time, a variety of parameters such as standard deviation can be utilized.
In Step S106, if the air velocity sensor 265 value is smaller than that of the air velocity sensor 275, then the controller 200 increases a fan duty of the fan 26 by a single step. As an example, the fan duty step is 5%, therefore, the fan 26 duty is increased from 60% to 65%. Accordingly, the airflow from both of the fans 26, 27 can be uniform.
On the other hand, in Step S107, if the value of the air velocity sensor 265 is greater than that of the sensor 275, then the controller 200 decreases a fan duty of the fan 26 by a single step. As an example, the fan duty step is 5%, therefore, the fan 26 duty is decreased from 60% to 55%. Accordingly, the airflow from both the fans 26, 27 can be uniform.
In Step S108, the controller 200 checks whether the fan duty tuning has been performed for all the fans. If not, then the controller 200 again starts the process from S103 by selecting a fan from the remaining fans. As an example, the fan 27 is selected.
In Step S109, after S108, if tuning is performed for all the set of fans, then the controller 200 calculates an airflow distribution. As an example, standard deviation can be utilized as airflow distribution parameters to decide whether airflow is homogenous or not.
In Step S110, if the controller 200 concludes that the airflow distribution isn't homogenous (NO in S109), then a next iteration of the fan duty tuning is performed. In Step S111, if the controller 200 concludes that the airflow distribution is homogenous (YES in S109), the controller 200 finishes the process with the tuning individual fan duty for the homogenous airflow at the heat exchanger surface exchanger surface 22.
In various embodiments, the exemplary steps of
This embodiment can implement a system, method and non-transitory computer readable storage medium capable of generating a uniform airflow at a heat exchanger surface.
In other embodiment as shown in
In other embodiment as shown in
With reference to
In S201, the controller 400 starts the fan operation set point process. As an example, fan duty will be utilized. Other parameters such as a fan RPM can also be utilized. In S202, the controller 400 sets, via a user input, a fan operation threshold for distinguishing a normal operation from an abnormal operation. If the difference between the set operation point and an actual operation is greater than a threshold, the fan will be flagged with the abnormal status, and then the flagged fan can be replaced during maintenance. As an example, a threshold is set at 10% for fan duty.
In S203, the controller 400 sets an operation point for the full set of fans. As an example, the controller 400 sets 60% fan duty to the fans 46 and 47. In S204, the controller 400 fetches a current operation point of each fan. As an example of a normal operation, the fan 46 is operating at 58% and the fan 47 is operating at 55%. As an example of an abnormal operation, the fan 46 is damaged and non-operation, therefore operating at 0%, while the fan 47 is operating at 55%.
In S205, the controller 400 calculates the difference between the set operation point and the current (or actual) operation point of a fan. As an example of normal operation, the operation difference when the fan 46 is operating at 58% is an absolute value of (60−58)=2%, while the operation difference when the fan 47 is operating at 55% is an absolute value of (60−55)=5%. Here, both of the fans 46 and 47 have an operation difference below the threshold (in this case, 10%) set by the user input in S202. As an example of an abnormal operation, the operation difference when the fan 46 is operating at 0% is the absolute value of (60−0)=60%, while the operation difference when the fan 47 is operating at 55% is the absolute value of (60−55)=5%. Here, the fan 46 has an operation difference above the threshold (in this case, 10%) set in S202, but the fan 47 has an operation difference below the threshold (in this case, 10%) set in S202.
In S206, the fan with the operation difference greater than threshold is flagged to be replaced during maintenance. As an example of an abnormal operation, the operation difference for fan 46 was 60%, which is higher than the threshold (10%) set in S202, therefore the fan is flagged.
In S207, if an abnormal operation is detected in S206, then the remaining fans are operated at a redundant operation set point. As an example, the redundant operation set point is 80%. In S208, the controller 400 finishes the process.
The system according to this embodiment can distinguish the normal operation from the abnormal operation for a plurality of fans and flag the fan which operates abnormally.
In various embodiments, the exemplary steps of
In yet other embodiments as shown in
In other embodiment as shown in
In other embodiment as shown in
The processor 81 performs processing of the information processing apparatus described with reference to the sequence diagrams and the flowchart in the above embodiments by reading software (computer program) from the memory 82 and executing the software. The processor 81 may be, for example, a microprocessor, an MPU or a CPU. The processor 81 may include a plurality of processors.
The processor 81 may include a plurality of processors. For example, the processor 81 may include a modem processor (e.g., DSP) which performs the digital baseband signal processing, a processor (e.g. DSP) which performs the signal processing of the GTP-U?UDP/IP layer in the X2-U interface and the S1-U interface, and a protocol stack processor (e.g., a CPU or an MPU) which performs the control plane processing.
The memory 82 is configured by a combination of a volatile memory and a non-volatile memory. The memory 82 may include a storage disposed apart from the processor 81. In this case, the processor 81 may access the memory 82 via an I/O interface.
The memory 82 is used to store software module groups. The processor 81 can perform processing of the information processing apparatus described in the above embodiments by reading these software module groups from the memory 82 and executing the software module groups.
In the aforementioned embodiments, the program(s) 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 flexible disks, magnetic tapes, hard disk drives, etc.), optical magnetic storage media (e.g., magneto optical disks), Compact Disc Read Only Memory (CD-ROM), CD-R, CD-R/W, and semiconductor memories (such as mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM), etc.). The program(s) 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 (e.g., electric wires, and optical fibers) or a wireless communication line.
While the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the aforementioned description. Various changes that may be understood by one skilled in the art may be made on the configuration and the details of the present disclosure within the scope of the present disclosure.
Part of or all the foregoing embodiments can be described as in the following appendixes, but the present invention is not limited thereto.
A system comprising:
A system according to note 1, further comprising a plurality of air velocity sensors provided at the heat exchanger, the plurality of air velocity sensors provided corresponding to the plurality of fans.
A system according to note 1, wherein the cooling unit body is installed between a rack top surface and a ceiling.
A system according to note 1, wherein the plurality of fans are configured to be connected to respective power lines and to be connected to respective signal lines.
A system according to note 1, further comprising a controller connected via separate signal lines to the plurality of fans, the controller configured to control the plurality of fans.
A system according to note 5, wherein the controller is configured to set a fan operation set point and fetch a current fan operation point.
A system according to note 6, wherein the controller is further configured to calculate an absolute difference value between the set operation points and an actual operation points;
A system according to note 1, wherein the plurality of fans are shifted towards one header of the heat exchanger so that the distance between the fan and the heat exchanger increases.
A system according to note 1, further comprising a casing in which the plurality of fans are placed, wherein the casing is detachable and can be removed without having to uninstalling the cooling unit body from an installed location.
A system according to note 1, further comprising an air interruption casing provided below the fan and configured to receive an air interruption plate.
A system according to note 1, further comprising an air filter casing which is removable without having to uninstalling the fan casing.
A method of tuning a fan operation in a system including: a cooling unit body having an airflow inlet and an airflow outlet; a heat exchanger provided inside the cooling unit body; and a plurality of fans provided at the airflow inlet, wherein the plurality of fans are configured to be connected to respective power lines and to be connected to respective signal lines, the method comprising:
The method according to note 12, comprising:
The method according to note 12, wherein the redundant fan operation set point is higher than a normal fan operation set point.
The method according to note 12, comprising:
The method according to note 15, wherein the air velocity of the selected sensor is compared with the remaining set of air velocity sensors.
A non-transitory computer readable storage medium storing instructions to cause a computer to perform the steps of:
The system and method for maintaining and improving airflow distribution uniformity at a heat exchanger surface according to the above embodiments can be used in a compact size cooling system.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/030802 | 8/13/2020 | WO |
