Techniques for controlling vapor pressure in an immersion cooling tank

Patent metadata

Field	Value
Publication number	US-9844166-B2
Application number	US-201615270435-A
Country	US
Kind code	B2
Filing date	Sep 20, 2016
Priority date	Feb 1, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

A pressure control system within a multi-phase heat transfer immersion cooling tank includes: a differential pressure transducer that measures a differential pressure between a first vapor pressure internal to the immersion cooling tank and a second pressure outside of the immersion cooling tank; and a condenser inflow valve assembly that controls a flow rate of condensation liquid within the condenser located within the immersion tank. The pressure control system also includes a controller coupled to both the differential pressure transducer and the condenser inflow valve assembly having control logic that, in response to the measured differential pressure exceeding a pre-set threshold difference, triggers the condenser inflow valve assembly to increase a flow rate of the condensation fluid in order to reduce an amount of vapor within the immersion tank and bring the measured differential pressure back to below the threshold difference.

First claim

What is claimed is:

1. A pressure control system within a multi-phase heat transfer immersion cooling tank, the pressure control system comprising:
a differential pressure transducer that measures a differential pressure between a first vapor pressure internal to the immersion cooling tank and a second pressure outside of the immersion cooling tank;
a condenser inflow valve assembly that controls a flow rate of condensation liquid within a condenser located within the immersion tank;
a controller coupled to both the differential pressure transducer and the condenser inflow valve assembly having control logic that, in response to the measured differential pressure exceeding a pre-set threshold difference, triggers the condenser inflow valve assembly to increase a flow rate of the condensation fluid in order to reduce an amount of vapor within the immersion tank and bring the measured differential pressure back to below the threshold difference; and
a bellows expansion lid positioned above the condensers within the immersion cooling tank and which in response to an increase in pressure of the rising vapor above a third threshold pressure level that is lower than the preset threshold difference, moves upwards into the lid of the immersion tank to substantially eliminate the increase in pressure, wherein the bellows expansion lid moves downwards to a base location within the upper tank volume in response to the amount of pressure within the tank reducing to below the third threshold pressure level.

2. The pressure control system of claim 1 , further comprising:
a condensation liquid cooling system that reduces a temperature of a portion of condensation fluid stored external to the immersion cooling tank; and
control logic that, in response to the measured differential pressure exceeding a second pre-set threshold difference that is higher than the pre-set threshold difference, triggers the condensation liquid cooling system to: provide a lower ambient temperature of the condensation fluid being supplied to the condenser, in order to increase a rate of vapor condensation due to a faster rate of heat absorption from the rising vapor by the cooler condensation fluid.

3. The pressure control system of claim 1 , wherein the controller is a condenser fluid flow controller that is connected to the differential pressure transducer in a feedback loop and which dynamically modulates flow of condensation fluid into the condensers based on a current measurement of differential pressure in order to maintain an amount of vapor within an upper volume of the immersion cooling tank within a pre-established operating range.

4. The pressure control system of claim 1 , wherein the control logic comprises a proportional-integral-derivative (PID) algorithm that is functionally coupled with a variable displacement solenoid valve on a supply-side of a facility cooling loop, wherein the solenoid valve is controlled by feedback provided by the differential pressure transducer.

5. The pressure control system of claim 1 , wherein a position of the bellows expansion lid within the upper tank volume is pre-selected based on empirical measurements to maximize an effect of the expansion of the bellows expansion lid on a pressure gradient within the tank.

6. The pressure control system of claim 1 , further comprising an external facility supply that provides the condensation fluid as a condensation liquid, wherein the external facility is located at a point horizontally above the condenser to allow the condensation fluid to flow via a difference in gradient and wherein the flow rate of condensation fluid through the condenser is controlled by a position of the condenser inflow valve assembly, which is determined by input received from the controller.

Assignees

• Dell Products Lp

Inventors

• Shelnutt Austin Michael
• Curlee James Don

Classifications

• G01F1/74 Primary

  Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid · CPC title

• H05K7/20236

  by immersion · CPC title

• F28F27/02

  for controlling the distribution of heat-exchange media between different channels ({static flow control means in header boxes F28F9/026}; arrangements of guide plates or guide vanes F28F9/22, F28F25/12) · CPC title

• H05K7/20281 Primary

  Thermal management, e.g. liquid flow control · CPC title

• H05K7/20809

  within server blades for removing heat from heat source · CPC title