PTAB

IPR2022-00328

OptiCool Technologies LLC v. Vertiv Corp

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petition

1. Case Identification

2. Patent Overview

  • Title: Two-Cycle Cooling System
  • Brief Description: The ’822 patent discloses a system for transferring heat from a load, such as a computer system, using two thermally connected cooling cycles with independent working fluids. The system features a first cooling cycle with a two-phase working fluid and a controller to maintain the fluid temperature above the dew point, preventing condensation on heat exchange components.

3. Grounds for Unpatentability

Ground 1: Anticipation - Claims 1, 6, 10, and 14 are anticipated by JP384.

  • Prior Art Relied Upon: JP384 (Japanese Patent Application Publication No. H05-157384A).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that JP384 discloses every element of the independent claims. JP384 teaches a "radiant cooling apparatus" with two refrigeration cycles thermally connected through a fluid-to-fluid heat exchanger. The first cycle (11) uses a pump (9) to circulate a two-phase refrigerant (e.g., R134a) through an air-to-fluid heat exchanger (10) that cools a heat load. The second cycle (8) uses a compressor (1) to transfer heat to the environment. Critically, JP384 discloses a controller (14) that measures the dew point (13) and controls a throttling device (7) to ensure the surface temperature of the heat exchanger remains above the dew point, thereby preventing condensation. This structure was alleged to meet all limitations of the challenged independent claims.

Ground 2: Obviousness over JP384 in view of US955 - Claims 1, 3, 6, 7, 10, 11, 14, 16, 20, 21, 23, and 24 are obvious over JP384 in view of US955.

  • Prior Art Relied Upon: JP384 and US955 (Patent 6,519,955).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that JP384 teaches the core two-cycle cooling system with dew point control, as detailed in Ground 1. For dependent claims requiring a "working fluid receiver," Petitioner asserted that while JP384 does not explicitly show this component, US955 does. US955, which discloses a pumped two-phase cooling system for electronic components, expressly teaches a "liquid receiver (36)" that holds a quantity of liquid refrigerant between the condenser and the pump.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references because both are directed to cooling computer equipment and preventing condensation. Petitioner argued that a working fluid receiver is a standard component in refrigeration systems to accommodate changes in fluid volume due to varying heat loads. A POSITA, recognizing the absence of this standard component in JP384, would look to analogous art like US955 and find it obvious to incorporate a receiver to improve system stability and reliability.
    • Expectation of Success: The inclusion of a standard receiver into a known cooling circuit was argued to be a straightforward modification using known techniques that would predictably result in a more reliable system.

Ground 3: Obviousness over US472 in view of US955 - Claims 1, 3, 6, 7, 10, 11, 14, 16, 20, 21, 23, and 24 are obvious over US472 in view of US955.

  • Prior Art Relied Upon: US472 (Patent 5,052,472) and US955 (Patent 6,519,955).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground used US472 as the primary reference, which discloses a two-cycle "temperature controlling system" for cooling computers. The first cycle in US472 uses a pump to circulate single-phase water, and the second refrigeration cycle controls the water temperature to avoid condensation. Petitioner argued that US472 does not explicitly disclose a two-phase working fluid in its primary cooling loop. However, US955 teaches that two-phase working fluids provide more efficient cooling with more uniform temperatures compared to the thermal capacity limitations of single-phase fluids like water.
    • Motivation to Combine: A POSITA would be motivated to improve the performance of the US472 system, which recognizes the difficulty of controlling water temperature. To address issues like inefficient heat transfer and the risk of condensation with high-density heat loads, a POSITA would replace the single-phase water circuit in US472 with the more efficient two-phase refrigerant system taught in US955. This combination was presented as a known technique to improve cooling systems.
    • Expectation of Success: Petitioner asserted that substituting a two-phase cooling circuit for a single-phase one was a well-known design choice with the predictable benefit of more efficient heat transfer and better temperature control.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on US472 in view of US893, and US893 in view of Liebert, but relied on similar arguments for combining known cooling system components to achieve predictable results.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that the grounds presented are not redundant of those considered during prosecution and that discretionary denial under §325(d) would be inappropriate. While US955 was submitted in an Information Disclosure Statement, it was part of a list of over 100 references and was never expressly evaluated, discussed, or cited as a basis for rejection by the Examiner. The remaining prior art references were not before the PTO at all.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1, 3, 6, 7, 10, 11, 14, 16, 20, 21, 23, and 24 of the ’822 patent as unpatentable.