PTAB

IPR2018-00514

Trane U.S. Inc. v. Semco, LLC

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1. Case Identification

2. Patent Overview

  • Title: System and Method For Controlling Temperature And Humidity
  • Brief Description: The ’388 patent discloses a heating, ventilation, and air conditioning (HVAC) system designed to control both temperature and humidity in a space. The invention centers on a specific configuration where a supply air stream passes sequentially through a total energy recovery wheel, a cooling coil, and a dehumidification wheel before entering the controlled space, with a return exhaust air stream used to regenerate the wheels.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3, 5-10, 12-15, 18-19, 25, 28-29, 36-37, 39-40, 42, 44, 46-47, and 49 under 35 U.S.C. §102 by Meckler.

  • Prior Art Relied Upon: Meckler (Patent 4,903,503).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Meckler, which issued in 1990, discloses an air conditioning apparatus that meets every limitation of the challenged claims. Specifically, Figure 62 of Meckler teaches a two-wheel system with an interstage cooling coil. Petitioner mapped Meckler’s first desiccant wheel (1251) to the claimed "total energy recovery device," its second desiccant wheel (1252) to the "dehumidification wheel," and its heat exchanger (1256) to the "cooler." Furthermore, Petitioner contended that Meckler’s separate ducts for supply and exhaust air (e.g., ducts 1261, 1268) meet the broadest reasonable construction of the claimed "partition," and its use of relief air (1258, 1259) to regenerate the wheels meets the "exhaust air stream" limitation.

Ground 2: Claims are obvious over Meckler in view of TWDS.

  • Prior Art Relied Upon: Meckler (Patent 4,903,503) and TWDS (a 1997 Federal Technology Alert titled "Two-Wheel Desiccant Dehumidification System").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Meckler teaches the core system of two desiccant wheels with an intermediate cooling coil. TWDS teaches a simplified, two-wheel HVAC system with a clear counterflow design, a simple partition between air streams, and a rotary heat exchanger that functions as a sensible-only energy recovery device.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the teachings to improve upon Meckler’s design. A POSITA would be motivated to replace the complex ductwork of Meckler with the simplified, cost-effective counterflow air stream configuration and partition taught by TWDS. For claim 36, which recites a "sensible energy recovery device," a POSITA would be motivated to substitute Meckler’s desiccant-based total energy wheel with the sensible-only rotary heat exchanger from TWDS in applications where deep dehumidification was not required, thereby reducing system cost.
    • Expectation of Success: A POSITA would have a high expectation of success, as the combination involves replacing known HVAC components with other known components to achieve the predictable functions of simplifying system construction and tailoring performance to specific humidity loads.

Ground 3: Claims are obvious over TWDS in view of TSDD.

  • Prior Art Relied Upon: TWDS (a 1997 Federal Technology Alert) and TSDD (a 1989 article by Gershon Meckler titled "Two-Stage Desiccant Dehumidification in Commercial Building HVAC Systems").

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that TWDS provides a basic two-wheel framework, including one desiccant wheel, a sensible heat exchanger, and standard air streams. However, TSDD provides the specific elements that TWDS lacks to meet the claims: a second desiccant wheel for enhanced dehumidification and a cooling coil located between the two wheels.
    • Motivation to Combine: A POSITA would be motivated to combine these references to create a system capable of the deep dehumidification required in humid climates. TWDS itself suggests that supplemental cooling is often needed. A POSITA would therefore look to a reference like TSDD, which explicitly teaches an inter-wheel cooling coil ("precooling coil") to improve performance. To further boost dehumidification, a POSITA would replace the sensible-only wheel in TWDS with the second desiccant-impregnated wheel taught by TSDD, resulting in the claimed configuration.
    • Expectation of Success: The combination uses well-known components for their intended purposes—adding more dehumidification capacity and precooling to improve efficiency. A POSITA would reasonably expect this combination of established technologies to function as intended.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge based on Meckler in view of the common knowledge of a POSITA. This ground argued that any minor differences between Meckler and the claims—such as the specific configuration of the partition or the use of a passive rather than active dehumidification wheel—would have been obvious and inconsequential modifications for a POSITA to make.

4. Key Claim Construction Positions

  • The petition proposed broad constructions for key terms, arguing they were consistent with the specification and necessary to properly evaluate the prior art.
  • "partition": Argued to mean any structure or structures separating the supply and exhaust air streams, including separate ducts, not just a single baffle. This construction allows the separate ductwork shown in Meckler to meet the limitation.
  • "exhaust air stream": Argued to broadly include any air exhausted or relieved from the controlled space or other sources, including return air. The petition highlighted that the ’388 patent specification explicitly supports this broad construction, which allows the "relief air" in Meckler to satisfy the claim element.
  • "total energy recovery device" vs. "sensible energy recovery device": The petition distinguished these terms based on their definitions in the specification, with the former exchanging both heat and moisture and the latter exchanging primarily heat. This distinction was central to the obviousness arguments for substituting one type of wheel for another based on operational needs.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-15, 18-19, 25, 28-29, 36-40, 42, 44-47, and 49 of Patent 6,199,388 as unpatentable under 35 U.S.C. §§ 102 and 103.