OptiCool Technologies LLC v. Vertiv Corp

1. Case Identification

• Case #: IPR2022-00329
• Patent #: 9,243,823
• Filed: December 21, 2021
• Petitioner(s): Opticool Technologies, LLC
• Patent Owner(s): Vertiv Corporation
• Challenged Claims: 1, 3, 6, 7, 10, 11, 14, 15, 16, 20, 21, 23, and 24

2. Patent Overview

• Title: Two-Cycle Cooling System for a Heat Load
• Brief Description: The ’823 patent discloses a cooling system for transferring heat from a heat load, such as a computer system. The system uses two thermally connected cooling cycles with independent working fluids, where a first cycle uses a two-phase fluid to absorb heat and a second cycle removes that heat from the first cycle.

3. Grounds for Unpatentability

Ground 1: Anticipation - Claims 1, 3, 6, 7, 10, 11, 14, 15, 16, 20, 21, 23, and 24 are anticipated by US955

• Prior Art Relied Upon: US955 (Patent 6,519,955).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that US955 discloses all limitations of the challenged claims. US955 teaches a pumped cooling system for electronic components that circulates a two-phase refrigerant. Petitioner asserted that US955's cold plate (18) serves as the claimed "first heat exchanger," and its optional "water or liquid cooled condenser" (28) functions as the claimed "fluid-to-fluid heat exchanger." This condenser creates two independent fluid paths (the refrigerant path and the coolant path) in thermal communication. Furthermore, US955 allegedly discloses a controller that prevents condensation by setting the system pressure and temperature such that the working fluid remains above the ambient dew point. For dependent claims, Petitioner pointed to US955’s express disclosure of a “liquid receiver” (36) positioned between the condenser and the pump.

Ground 2: Obviousness - Claims 1, 3, 6, 7, 10, 11, 14, 15, 16, 20, 21, 23, and 24 are obvious over JP384 in view of US955

• Prior Art Relied Upon: JP384 (Japanese Patent Application Publication No. H05-157384A) and US955 (Patent 6,519,955).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that JP384, a reference for a "radiant cooling apparatus," discloses a two-cycle cooling system that meets nearly all limitations of the independent claims. It includes a first cycle with a pump, a two-phase working fluid, an air-to-fluid heat exchanger, and a fluid-to-fluid heat exchanger, as well as a second cycle and a controller to prevent condensation. However, Petitioner argued that JP384 does not explicitly disclose a "working fluid receiver," a limitation required by several dependent claims. This missing element, a "liquid receiver," is expressly taught by US955 for storing excess refrigerant.
  • Motivation to Combine: Petitioner argued a POSITA would combine the teachings because both references are analogous art aimed at cooling equipment while preventing condensation. While a working fluid receiver is a standard component in refrigeration systems, it is not shown in JP384. A POSITA seeking to improve the reliability of the JP384 system to handle changes in temperature and heat load would have looked to known solutions. US955, a widely cited patent in the field, provides an express teaching of incorporating a receiver to store and accumulate working fluid, which would have been an obvious modification to the JP384 system.
  • Expectation of Success: A POSITA would have a reasonable expectation of success because incorporating a fluid receiver into a two-phase system is a familiar, straightforward design modification with predictable results, leading to a more reliable cooling system.

Ground 3: Obviousness - Claims 1, 3, 6, 7, 10, 11, 14, 15, 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: Petitioner asserted that US472 discloses a two-cycle cooling system for computers that includes a first fluid circuit with a pump, air-to-fluid heat exchangers, and a fluid-to-fluid heat exchanger, as well as a second refrigeration circuit. US472 also discloses a controller to prevent condensation. The primary difference alleged is that US472's first circuit uses single-phase cooling water, not the claimed "two-phase working fluid." US955 remedies this deficiency by teaching a cooling system that uses a two-phase refrigerant specifically to achieve higher heat transfer rates than single-phase fluids like water.
  • Motivation to Combine: Petitioner argued a POSITA would be motivated to modify the US472 system by replacing its single-phase water with the two-phase refrigerant taught by US955. US472 itself recognizes that controlling water temperature is difficult, and US955 directly addresses the thermal capacity limitations of single-phase fluids when cooling high-density electronics. A POSITA, faced with the known problems of single-phase cooling, would have found it obvious to incorporate the more efficient two-phase cooling solution from US955 into the system of US472 to improve performance, reduce pumping power, and achieve more uniform temperatures.
  • Expectation of Success: The combination would be a simple substitution of a known technique (two-phase cooling) to improve a known system (US472), with predictable results in cooling efficiency.

• Additional Grounds: Petitioner asserted anticipation of independent claims 1, 6, 10, and 14 over JP384. Petitioner also asserted obviousness challenges over US472 in view of US893 (Patent 5,784,893) and over US893 in view of Liebert (a 2001 brochure), which relied on similar motivations to combine analogous art to add missing claim elements like two-phase fluids or dew point control.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate. It was asserted that the arguments presented are not cumulative to those considered during prosecution because the vast majority of the cited prior art, including JP384, US472, US893, and Liebert, was never before the PTO. While US955 was submitted by the Patent Owner in an Information Disclosure Statement, it was one of 158 references and was never expressly evaluated, discussed by the Examiner, or cited as a basis for any rejection.

5. Relief Requested

• Petitioner requests institution of inter partes review and cancellation of claims 1, 3, 6, 7, 10, 11, 14, 15, 16, 20, 21, 23, and 24 of the ’823 patent as unpatentable.