The present invention is related to a leak detection system for a liquid cooling system, and liquid cooling systems that incorporate the leak detection system.
Computers, and other electronic systems, include integrated circuit (IC) devices that generate heat during operation. For effective operation of the computer, the temperature of these IC devices has to be maintained below acceptable limits. While the problem of heat removal from IC devices is an old one, this problem has increased in recent years due to greater numbers of transistors that are packed into an IC device while reducing the physical size of the device. Increasing number of transistors compacted into a smaller area results in a greater concentration of heat that must be removed from that smaller area. Bundling multiple computer systems together, such as, for example, in a computer server, further aggravates the heat removal problem by increasing the amount of heat that has to be removed from a relatively small area.
U.S. application Ser. No. 13/215,384, filed Aug. 23, 2011, titled “Liquid Cooling System for a Server” discloses an exemplary liquid cooling system that may be used to effectively cool multiple nodes of a computer server. In the cooling system of the '384 application, a liquid coolant is circulated through the multiple nodes to cool the heat producing components of the server. One of the major concerns of applying liquid cooling systems to a computer is the possibility of coolant leaks occurring within the computer. While coolant leaks may be minimized with proper design of the cooling system, it may be impractical to design a totally leak proof system. The current disclosure is directed to addressing these and other limitations of existing liquid cooling systems.
In one aspect, a liquid cooling system for a computer is disclosed. The cooling system may include a cold plate configured to be positioned on a heat generating electronic device of the computer. The cold plate may be adapted to pass a coolant therethrough. The cooling system may also include a leak detection system configured to detect a coolant leak in the computer, and a control system coupled to the leak detection system. The control system may be configured to take remedial action when the coolant leak is detected by the leak detection system.
In another aspect, a liquid cooling system for a computer server is disclosed. The computer server may include multiple nodes arranged on a rack. The cooling system may include a first liquid loop configured to pass a coolant through a first node of the multiple nodes, and a second liquid loop configured to pass the coolant through a second node of the multiple nodes. The cooling system may also include a leak detection system configured to detect a coolant leak in the server, and a control system operatively coupled to the leak detection system and the first and second liquid loops. The control system may be configured to identify a node of the server in which the coolant leak occurred.
In yet another aspect, a liquid cooling system for a server room is disclosed. The server room may include multiple computer servers and each of the multiple servers may include multiple nodes arranged on a rack. The cooling system may include a liquid loop configured to pass a coolant through a plurality of nodes of the multiple computer servers to cool one or more electronic devices positioned in the plurality of nodes. The cooling system may also include a leak detection system configured to detect a coolant leak in the plurality of nodes, and a control system operatively coupled to the leak detection system and the liquid loop. The control system may be configured to identify a node of the plurality of nodes in which the coolant leak occurred.
The following detailed description illustrates the cooling system by way of example and not by way of limitation. Although the description below describes an application of the disclosed liquid cooling system to computer servers housed in a server room, embodiments of the disclosed cooling systems may be applied to cool heat generating components in any application. For example, embodiments of the current disclosure may be used to cool desktop computers, portable computers, or any other electronic system. The description enables one skilled in the art to make and use the present disclosure for cooling any electronic component within a console or a chassis.
Reference will now be made to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Elements designated using the same reference numbers in different figures perform similar functions. Therefore, for the sake of brevity, these elements may not be described with reference to every figure. In the description that follows, if an element is not described with reference to a figure, the description of the element made with reference to another figure applies.
Node 12 may also include a liquid cooling system 22 to cool one or more of the heat generating electronic devices 18. Liquid cooling system 22 may include one or more cold plates 24 placed in thermal contact (directly in contact, or in contact through a heat transfer medium, such as, for example, thermal grease or a thermal pad) with one or more of electronic devices 18 to cool these devices. Because of thermal contact, heat may be transferred from the electronic device 18 to the cold plate 24. A coolant of the liquid cooling system 22 may pass through the cold plate 24 to remove heat from, and thereby cool, the cold plate 24. Any type of apparatus configured to transfer heat from an electronic device 18 to a circulating coolant may be used as the cold plate 24. The cold plate 24 may include fins, pins, or other such features to assist in transferring the heat from the cold plate 24 to the coolant. In some embodiments, devices used to transfer heat from heat generating electronic devices to the coolant described in co-assigned U.S. Pat. Nos. 7,971,632, 8,240,362, 8,245,764, 8,274,787, 8,358,505, and U.S. patent application Ser. Nos. 11/919,974, 12/914,263, and 13/593,157 with appropriate modifications, may be used as the cold plate 24. These patent applications are incorporated by reference herein in their entirety. Although
The coolant may dissipate the heat from the cold plates 24 to another medium (such as, air or another liquid) at a heat exchanger (not shown). The relatively cooler coolant may then be circulated back to the cold plates 24 to absorb more heat and continue the cycle. The liquid cooling system 22 may include one or more pumps or other circulation devices (not shown) to circulate the coolant between the cold plates 24 and the heat exchanger. In some embodiments, the pump and control circuits that controls the operation (for example, speed, etc.) of the pump may be integrated with the cold plates 24 (see, for example, some of the cold plates described in U.S. Pat. Nos. 8,240,362 and 8,245,764). In some embodiments, the pump may be provided separate from the cold plates 24 (see for example, the cold plates described in U.S. Pat. Nos. 8,274,787 and 8,358,505). It is also contemplated that, some configurations of the liquid cooling system 22 may not include a pump. In such embodiments, the liquid cooling system 22 may instead rely upon the expansion and contraction of the coolant as it absorbs and dissipates heat to propel the coolant between the heat exchanger and the cold plates 24.
Any liquid, such as, for example, water, alcohol, mixtures of alcohol and water, etc. may be used as the coolant in liquid cooling system 22. In some embodiments, the coolant may also include an additive adapted to produce a desired characteristic (such as, smell, color, etc.) in coolant. Although the coolant is described as a liquid, in some embodiments, a phase change material may be used as the coolant. In these embodiments, a coolant in a liquid phase may transform to a gaseous phase after absorption of heat at a cold plate 24. The coolant may transform back to the liquid phase after transferring the absorbed heat to another medium at the heat exchanger. Although not illustrated in
Multiple nodes 12 of server 10 may include liquid cooling systems. The liquid cooling systems of the multiple nodes may be similar to, or different from, liquid cooling system 22.
Although proper design of a liquid cooling system 22 may minimize the possibility of a coolant leak in a node 12, it may be impractical to eliminate this possibility entirely. Coolant leak in a node 12 may affect the functioning of, or even damage, node 12. Therefore, liquid cooling system 22 may include a leak detection system adapted to detect a coolant leak, and indicate the node 12 in which the leak is occurring. Based in this indication, the central control system 30 (or in some embodiments, an operator) may shut off the coolant supply to selected nodes 12 and/or take other remedial measures.
The leak detection system may comprise a leak detector associated with a node 12. In some embodiments, the leak detector may take the form of a substrate 26 having a leak detection circuit formed thereon. The leak detection circuit may be adapted to detect coolant leak.
Although
In some embodiments, the leak detection circuit 28 may be incorporated on, or attached to, the front side of the motherboard 16. In some such embodiments, the leak detection circuit 28 may include spaced apart conductive traces 32 (or other suitable structures) patterned and formed on the motherboard 16. In some embodiments, the conductive traces 32 may be formed on a film (similar to substrate 26), and the film attached to desired regions on the front side of the motherboard 16. These conductive traces 32 may generally be provided in regions of the motherboard 16 that are most likely to experience coolant leak, and oriented such that the leaked coolant flows under the force of gravity on to the conductive traces 32. For example, conductive traces 32 may be provided in a region of the motherboard 16 proximate cold plates 24, and/or in regions of the motherboard proximate separable fluid couplings of the liquid cooling system 22. The conductive traces 32 of the leak detection circuit 28 may then be electrically coupled to the central control system 30 to detect the presence of the leaked coolant.
In some embodiments, as illustrated in
When coolant leak is detected in a node 12 of the server 10, the control system 30 may take remedial action. The remedial action may include selectively turning off the coolant supply to the node 12 and/or alerting an operator (by activating an alarm, indicator light, etc.) of the leak. In some embodiments, upon detection of a leak, the control system 30 may additionally or alternatively selectively deactivate the node 12 in which the leak occurred to prevent damage to the node 12.
Although the leak detection systems above are described as being electrically connected to the central control system 30 of the server room, this is not a requirement. In some embodiments, the leak detector of a liquid cooling system 22 may be electrically connected to a control system of the liquid cooling system 22 (for example, the control circuits integrated with the cold plate 24). In such embodiments, the liquid cooling system 22 may turn itself off, or take other remedial actions when a leak is detected. It is also contemplated that, in some embodiments, the liquid cooling systems 22 (with its associated pumps, fans, etc.) and/or the leak detection systems (leak detection circuit 28, sensor 36, etc.) may be coupled to the control system 30 (or another control circuit) wirelessly.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed liquid cooling system with a leak detection system. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed cooling systems. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.