PTAB

IPR2022-00330

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 ’126 patent discloses a cooling system for transferring heat from a heat load, such as computer equipment. The system uses two thermally connected cooling cycles with independent working fluids, where a controller prevents condensation by maintaining the temperature of the first cycle's working fluid above the dew point of the surrounding air.

3. Grounds for Unpatentability

Ground 1: Claims 1, 3, 5, 6, 8, 9, 11, 13, 20, and 21 are obvious over US893 in view of Liebert.

  • Prior Art Relied Upon: US893 (Patent 5,784,893) and Liebert (Liebert DataCool Website and Brochure).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that US893 discloses a two-circuit cooling system with all major structural components of the challenged claims, including a first cooling circuit with a pump, a two-phase working fluid, an air-to-fluid heat exchanger, and a fluid-to-fluid heat exchanger. The second circuit also uses a refrigerant to transfer heat to the environment. However, US893 does not explicitly teach controlling the system to prevent condensation. Liebert, a brochure for a commercial two-circuit cooling system for computer equipment, expressly discloses a controller that maintains the fluid temperature above the dew point to prevent condensation on the coils.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA), starting with the system in US893, would recognize the well-known problem of condensation and would be motivated to look for known solutions. A POSITA would combine the analogous teachings of Liebert to incorporate its dew point control feature into the US893 system to prevent equipment damage from condensation.
    • Expectation of Success: The integration of a standard dew point controller into a cooling system was a straightforward design choice with predictable and successful results.

Ground 2: Claims 1, 3, 5, 6, 8, 9, 11, 13, and 20 are obvious over US955 in view of Liebert.

  • Prior Art Relied Upon: US955 (Patent 6,519,955) and Liebert.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that US955 discloses a pumped, two-phase cooling system for electronic components that inherently prevents condensation by controlling system pressure and temperature to remain above ambient dew point. US955 also discloses a fluid receiver. The system lacks an explicit disclosure of using a building's chilled water system for the secondary cooling loop. Liebert discloses this feature, describing a coolant distribution unit (CDU) that interfaces with a building's chilled water system to expel heat.
    • Motivation to Combine: A POSITA would combine the references for two primary reasons. First, a POSITA would be motivated to use a common building chilled water system (from Liebert) as the heat rejection mechanism for the advanced two-phase cooling loop of US955. Second, a POSITA would be motivated to replace Liebert's less efficient single-phase cooling loop with US955's more effective two-phase loop, as US955 explicitly teaches that two-phase cooling is superior for high-power electronics.
    • Expectation of Success: The combination was argued to be predictable because it involves integrating a standard facility utility (chilled water) with a cooling system or, alternatively, substituting a known, more efficient cooling technology for a less efficient one to handle higher heat loads.

Ground 3: Claims 1, 3, 5, 6, 8, 9, 11, 13, 20, and 21 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: Petitioner argued that US472 discloses the basic framework of a two-cycle cooling system for computer equipment that includes dew point control. However, US472’s primary cooling loop uses a single-phase fluid (water). US955 teaches a pumped cooling system that uses a more thermally efficient two-phase working fluid and discloses a working fluid receiver.
    • Motivation to Combine: A POSITA would be motivated to improve upon the US472 system, which itself recognizes the limitations and control difficulties of single-phase water cooling. To address these known issues, especially for high-density heat loads, a POSITA would replace US472's single-phase water with the superior two-phase refrigerant system taught by US955. This substitution would increase heat transfer efficiency and provide more uniform temperatures.
    • Expectation of Success: Petitioner asserted that substituting a two-phase cooling circuit for a single-phase one was a well-known technique for improving cooling systems, and a POSITA would have had a high expectation of success in achieving a more efficient system with predictable results.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 4) based on US472 in view of US893, which relied on a similar theory of substituting the two-phase refrigerant system of US893 for the single-phase water system of US472.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §325(d) would be inappropriate. It contended that the asserted prior art combinations and arguments are new and noncumulative, as most references were not before the PTO during prosecution. Furthermore, while US955 was cited in an Information Disclosure Statement, it was part of a list of over 160 references and was never substantively evaluated, discussed, or relied upon by the Examiner for any rejection.

5. Relief Requested

  • Petitioner requests institution of inter partes review (IPR) and cancellation of claims 1, 3, 5, 6, 8, 9, 11, 13, 20, and 21 of the ’126 patent as unpatentable.