Automated Venting and Refilling of Multiple Liquid Cooling Systems

Abstract

A two-phase liquid cooling system includes an active venting system for regulating an amount of non-condensable gas within the cooling system. Various venting structures may be used to remove gases from the cooling system, some of which are designed to remove the non-condensable gases and avoid removing the vapor-phase coolant. A control system activates the venting system to achieve a desired pressure, which may be based on measured process conditions within the cooling system. A venting and refilling system may serve multiple cooling systems in a parallel arrangement.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of co-pending U.S. application Ser. No. 11 / 384,195, filed Mar. 17, 2006, which claims the benefit of U.S. Provisional Application No. 60 / 775,496, filed Feb. 21, 2006. Each of the foregoing applications is incorporated by reference in its entirety.BACKGROUND[0002]1. Field of the Invention[0003]This invention relates generally to two-phase liquid cooling systems, and more particularly to venting and refilling multiple two-phase liquid cooling systems, such as those configured to cool rack mounted electronics.[0004]2. Background of the Invention[0005]Liquid cooling is well known in the art of cooling electronics. As air cooling heat sinks continue to be pushed to new performance levels, so has their cost, complexity, and weight. Because computer power consumptions will continue to increase, liquid cooling systems will provide significant advantages to computer manufacturers and electronic system pro...

AI Technical Summary

Benefits of technology

[0012]To avoid at least some of the problems encountered with existing two-phase liquid cooling systems, as described above, a cooling system with active venting is provided. An active venting system actively regulates the pressure within the cooling system, for example, by regulating the amount of non-condensable gases in the cooling system. With appropriate control of the active venting system, the performance and reliability of the system can be increased and maintained over long and continuous periods of operation.

[0014]The active cooling system can exhaust gases out of the system using various mechanisms. In one embodiment, a vent is located between the cooling module and the pump, and an auxiliary pump is coupled to the vent to pump a desired amount of gas out of the system. The control system is coupled to the auxiliary pump and vent to provide the ability to regulate the amount of gas removed from the system. The active venting system may also be capable of adding gases into the cooling system (e.g., by pumping air into the system) when a pressure increase is desired. In this way, the cooling system can regulate the pressure in the cooling system to achieve a desired overall cooling efficiency. Adding air to the cooling system may also help avoid cavitation in the pumps.

[0018]Multiple liquid cooling systems can also be vented and / or refilled in a parallel arrangement. In one embodiment of such a system, a central system is coupled to the exhaust paths of a number of liquid cooling systems. The central system may be selectably coupled to the exhaust paths by controllable valves. When desired, the system removes exhaust gases from one or more of the cooling systems and vents the exhaust gases. Condensed coolant may be collected, and the system may supply coolant liquid to one or more of the cooling systems via input ports, which may be coupled to the refilling system via controllable valves. When applied to multiple parallel cooling systems, such as multiple racks of liquid-cooled servers found in a data center, this embodiment allows for the automated venting and refilling of an entire system from a centralized location.

Problems solved by technology

Air is a common non-condensable gas in cooling systems, since they are typically run at pressures below atmospheric so that air tends to seep in slowly through points in the system that are not completely sealed or otherwise allow air permeation into the system.

The non-condensable gases cause a partial pressure within the closed volume of the cooling system, which alters the boiling point of the cooling fluid and thus affects the operation of the cooling system.

Otherwise, over time the cooling system would lose coolant and would need to have the coolant replaced.

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