Testing for Leaks in a Two-Phase Liquid Cooling System

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. A return path of the cooling system can be tested for coolant leaks by increasing the pressure in the return path and placing a coolant detector near the path.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 60 / 775,496, filed Feb. 21, 2006, which is incorporated by reference in its entirety. This application is also related to U.S. application Ser. No. 11 / 384,195, filed Mar. 17, 2006, and to U.S. application Ser. No. 11 / 466,076, filed Aug. 21, 2006, each of which is incorporated by reference in its entirety.BACKGROUND[0002]This invention relates generally to two-phase liquid cooling systems, such as those configured to cool rack-mounted electronics, and more particularly to detecting coolant leaks in two-phase liquid cooling systems.[0003]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 elect...

AI Technical Summary

Benefits of technology

[0010]In one embodiment, a two-phase cooling system directs a coolant via a supply path to one or more cooling modules and collects the coolant via a return path in a thermal management unit, which cools and redeploys the coolant to the cooling modules. During normal operation of the cooling system, the return path is at a pressure below atmospheric pressure. A control unit is coupled to the cooling system and, when leak testing is desired, the control unit increases the pressure of the return path to a pressure at or above atmospheric pressure. In this diagnostic mode, a sensor can be used to detect any coolant leaking from the return path of the cooling system. Once the testing is completed, the control unit can return the cooling system to its normal operation.

Problems solved by technology

As air cooling heat sinks continue to be pushed to new performance levels, so has their cost, complexity, and weight.

Leaks in the system can throw these parameters off balance, as leaks can result in non-condensable air added to the system or coolant loss from the system.

The result of leaks is often to degrade the thermal performance of the system.

If the detector is located near the vicinity of a leak in which coolant is leaking from the system, the detector will indicate the presence of the coolant and, therefore, a leak in the system.

For this reason, any leaks in the return path generally result in air leaking into the system rather than coolant leaking out of the system.

The refrigerant detector—or any kind of external sensor—is not helpful in such a case.

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