PTAB

IPR2014-01172

CoolIT Systems Inc v. Asetek AS

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Liquid Cooling System for a Server
  • Brief Description: The ’968 patent discloses a liquid cooling system for servers in a computer rack. The system uses a first, internal liquid cooling loop to transfer heat from a server component to a liquid-to-liquid heat exchanger, which in turn transfers the heat to a second, external liquid cooling loop for removal.

3. Grounds for Unpatentability

Ground 1: Obviousness over Chu and Konshak - Claims 1-6, 8, 9, and 11-14 are obvious over Chu in view of Konshak.

  • Prior Art Relied Upon: Chu (Patent 7,012,807) and Konshak (Application # 2007/0297136).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Chu disclosed a liquid cooling system for a rack-mounted "electronics drawer" that contained all elements of claim 1 except for the explicit recitation of a "server module." Chu taught a "first cooling loop" inside the drawer with a cold plate on a processor, and a "second cooling loop" at the rack level. The liquid-to-liquid heat exchanger was disclosed as the combination of Chu's "heat rejection cold plate" (part of the first loop) and the rack's "system cold plate" (part of the second loop), which are placed in thermal contact when the drawer is docked. Konshak was cited to supply the teaching that the modular components in such rack systems can be "servers."
    • Motivation to Combine: Petitioner contended a person of ordinary skill in the art (POSITA) would combine the teachings because Chu and Konshak were analogous references addressing cooling for rack-mounted computer systems. Konshak provided an express motivation by describing the economic and environmental benefits of consolidating electronic components, including servers, into a single rack location. A POSITA would have found it obvious to apply Chu's detailed cooling architecture to the server modules described in Konshak to achieve these known benefits.
    • Expectation of Success: The combination was argued to be predictable, as it involved applying a known cooling system (Chu) to a known type of rack-mounted component (Konshak's servers), resulting in a cooled server module as expected.

Ground 2: Obviousness over Chu, Konshak, and Carlson - Claim 7 is obvious over Chu in view of Konshak and Carlson.

  • Prior Art Relied Upon: Chu (Patent 7,012,807), Konshak (Application # 2007/0297136), and Carlson (Application # 2008/0029250).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the Chu and Konshak combination, which Petitioner argued taught a "heat exchanger" as part of a cooling device (per claim 6). Claim 7 requires this heat exchanger to be a second liquid-to-liquid heat exchanger. Petitioner asserted that Carlson disclosed various external cooling devices for data centers, including a cooling tower that incorporates a "water-to-water heat exchanger." This component in Carlson directly maps to the claimed limitation.
    • Motivation to Combine: Petitioner argued a POSITA would substitute the general "condenser" taught as part of Konshak's cooling resource with the specific water-to-water heat exchanger from Carlson for a compelling reason: cost savings. Carlson explicitly taught that using such a system avoids the high electrical cost of operating a traditional chiller, providing a strong and direct motivation for the substitution.
    • Expectation of Success: The substitution of one known heat rejection component (a condenser) with another (a liquid-to-liquid heat exchanger) to achieve a known benefit (cost savings) was a simple design choice with a predictable outcome.

Ground 3: Obviousness over Chu, Konshak, and Chu ’705 - Claims 10 and 15 are obvious over Chu in view of Konshak and Chu ’705.

  • Prior Art Relied Upon: Chu (Patent 7,012,807), Konshak (Application # 2007/0297136), and Chu ’705 (Application # 2005/0128705).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground also built upon the primary Chu and Konshak combination. Claims 10 and 15 require the addition of "fins" to the first cold plate and the heat sink, respectively, to assist in heat transfer. Petitioner argued that Chu ’705, which shares inventors with the primary Chu reference, explicitly disclosed a cold plate with "a set of high thermal conductivity fins" to improve heat transfer.
    • Motivation to Combine: A POSITA would combine these teachings because adding fins to cold plates and heat sinks was a well-known, fundamental technique to increase surface area and improve thermal performance. Chu ’705 provided an express disclosure of this principle and its benefits, such as increased heat removal capability. A POSITA would have been motivated to make this simple modification to the system in Chu to predictably improve its cooling efficiency.
    • Expectation of Success: Incorporating fins as taught by Chu ’705 into the cold plates of the Chu system was a routine design modification that would have predictably resulted in enhanced heat transfer.

4. Key Claim Construction Positions

  • "cold plate": Petitioner argued this term should be construed as "any device or component that enables heat transfer between a coolant and a heat exchange surface," based on language in the ’968 patent’s specification.
  • "liquid cooling loop": Based on the specification’s description of a "closed loop liquid cooling system," Petitioner proposed this term be construed as "a liquid circuit arranged to deliver a corresponding liquid coolant for absorbing heat."
  • "liquid-to-liquid heat exchanger": As the specification did not use this exact phrase, Petitioner argued that based on the knowledge of a POSITA and the claim language, it should be construed as "a device configured to facilitate the transfer of heat from a first liquid medium to a second liquid medium."
  • "heat sink": Petitioner noted this term was absent from the ’968 patent’s description but present in a provisional application. Based on its common meaning in the industry, it was proposed to be construed as "a device for facilitating the rejection of heat."

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-15 of the ’968 patent as unpatentable based on the grounds presented.