Prosecution Insights
Last updated: April 19, 2026
Application No. 18/292,578

A STORAGE DEVICE FOR THERMAL ENERGY

Final Rejection §103
Filed
Jan 26, 2024
Examiner
RUPPERT, ERIC S
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
David S R L
OA Round
2 (Final)
59%
Grant Probability
Moderate
3-4
OA Rounds
2y 10m
To Grant
83%
With Interview

Examiner Intelligence

Grants 59% of resolved cases
59%
Career Allow Rate
437 granted / 739 resolved
-10.9% vs TC avg
Strong +24% interview lift
Without
With
+24.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
55 currently pending
Career history
794
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
48.5%
+8.5% vs TC avg
§102
21.1%
-18.9% vs TC avg
§112
27.3%
-12.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 739 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claim(s) 1-3, 6-7, 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lotfalian (US20230243600A1) in view of MacCracken (US4286141A). Regarding claim 1, Lotfalian discloses a thermal energy storage (see Fig. 1-2) device including: a thermovector unit (120), and a thermoaccumulator unit (150), wherein: said thermoaccumulator unit comprises a granular thermoaccumulator material (granular material - ¶[0124]), said thermoaccumulator unit comprises an interstitial volume defined by the granular thermoaccumulator material of said thermoaccumulator unit, said interstitial volume (porous channel - ¶[0144]) being pervious with respect to a thermovector fluid (working fluid 201-204) configured to flow through the interstitial volume in a flow direction and in thermal exchange relationship with the granular thermoaccumulator material of the thermoaccumulator unit for the storage and release of thermal energy as a consequence of a thermal exchange with said thermovector fluid, said granular thermoaccumulator material is arranged in an internal volume of a shell (cylindrical shape…pipe or tube - ¶[0151]) of said thermal storage device, said internal volume has a characteristic dimension transverse to the flow direction of the thermovector fluid, and a ratio between an average characteristic dimension of the granular thermoaccumulator material and said characteristic dimension transverse to the flow direction of the thermovector fluid is comprised between 0.001-0.1 (¶[0158]), overlapping the claimed range of 0.01 and 0.20. Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Lotfalian to have selected the overlapping portion of the ranges disclosed by the reference because selection of overlapping portion of ranges has been held to be a prima facie case of obviousness. See MPEP § 2144.05.I. Lotfalian does not teach said thermoaccumulator material comprises a packing or filling degree of between 58% to 64% of the internal volume of said shell, which corresponds to a respective vacuum degree between 46% and 36%. MacCracken teaches said thermoaccumulator material comprises a packing or filling degree of between 60-80% of the internal volume of said shell, which corresponds to a respective vacuum degree between 40-20% (Col. 2, lines 5-20, overlapping the claimed ranges). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Lotfalian with the packing and vacuum degrees of MacCracken, in order to balance the surface area and pressure drop (Col. 2, lines 5-20). See also MPEP § 2144.05.I. Regarding claim 2, Lotfalian teaches the limitations of claim 1, and Lotfalian further teaches wherein said ratio between the average characteristic dimension of the granular thermoaccumulator material and said characteristic dimension transverse to the flow direction of the thermovector fluid is between 0.001-0.1 (¶[0158]), overlapping the claimed range of 0.01 and 0.15. Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Lotfalian to have selected the overlapping portion of the ranges disclosed by the reference because selection of overlapping portion of ranges has been held to be a prima facie case of obviousness. See MPEP § 2144.05.I. Regarding claim 3, Lotfalian teaches the limitations of claim 1, and Lotfalian further teaches said granular thermoaccumulator material has the average characteristic dimension is between 1 and 10 cm (¶[0124]), overlapping the claimed range of 1.6 cm and 5.6 cm. Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Lotfalian to have selected the overlapping portion of the ranges disclosed by the reference because selection of overlapping portion of ranges has been held to be a prima facie case of obviousness. See MPEP § 2144.05.I. between 1.6 cm and 5.6 cm. Regarding claim 6, Lotfalian teaches the limitations of claim 1, and Lotfalian further teaches said shell has a cylindrical shape, said transverse characteristic dimension with respect to the direction of flow of the thermovector fluid comprising an internal diameter of said shell (cylindrical - ¶[0151] & internal diameter - ¶[0158]). Regarding claim 7, Lotfalian teaches the limitations of claim 1, and Lotfalian further teaches said shell has a prismatic shape, said characteristic dimension transverse to the flow direction of the thermovector fluid being a hydraulic diameter of the shell, said hydraulic diameter being defined as a ratio between a quadruple of a flow section of the internal volume of the shell and a wet perimeter of the internal volume of the shell (this is inherently the ratio for a cylindrical tube, see cylindrical - ¶[0151] & internal diameter - ¶[0158]). Regarding claim 10, Lotfalian further teaches an array of thermal energy storage devices including a plurality of thermal energy storage devices according to claim 1 hydraulically connected to each other (coupled in parallel or in a series configuration - ¶[0255]). Claim(s) 4-5 and 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lotfalian (US20230243600A1) in view of MacCracken (US4286141A) and Pranov (US20210190438A1). Regarding claims 4-5, Lotfalian teaches the limitations of claim 1, and Lotfalian does not teach said granular thermoaccumulator material is chemically inert to the thermovector fluid and insoluble therein or said granular thermoaccumulator material has thermal diffusivity lower than or equal to 35 mm.sup.2/s Pranov teaches wherein said granular thermoaccumulator material is chemically inert to the thermovector fluid and insoluble therein or said granular thermoaccumulator material has thermal diffusivity lower than or equal to 35 mm.sup.2/s (quartz and granite are considered by be inert to air and have a thermal diffusivity lower than or equal to 35 mm.sup.2/s - ¶[0100]). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified Lotfalian to include granite as taught by Pranov, in order to provide a material suitable to undergo numerous cycles of heating and cooling without breaking or decomposing (¶[0100]). Regarding claim 8, Lotfalian teaches the limitation of claim 4, and Lotfalian further teaches wherein said shell comprises: a tubular element having an internal lumen, a first end element at a first end of the tubular element, a second end element at a second end of the tubular element, opposite to said first end, the first end element and the second end element defining, with said internal lumen of the tubular element, the internal volume of the shell, each of said first and second end elements comprising a respective arrangement of holes configured to enable transit of said thermovector fluid through said internal volume in the flow direction (see 120 & tube - ¶[0142] & perforated plates - ¶[0162]). Response to Arguments Applicant’s arguments with respect to the claim(s) have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Allowable Subject Matter Claim 9 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIC S RUPPERT whose telephone number is (571)272-9911. The examiner can normally be reached Monday - Friday 8 am - 4 pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Len Tran can be reached at 571-272-1184. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ERIC S RUPPERT/Primary Examiner, Art Unit 3763
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Prosecution Timeline

Jan 26, 2024
Application Filed
Aug 04, 2025
Non-Final Rejection — §103
Jan 05, 2026
Response Filed
Mar 13, 2026
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
59%
Grant Probability
83%
With Interview (+24.1%)
2y 10m
Median Time to Grant
Moderate
PTA Risk
Based on 739 resolved cases by this examiner. Grant probability derived from career allow rate.

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