Prosecution Insights
Last updated: October 21, 2026
Application No. 18/900,274

Thermal Storage

Final Rejection §102§103
Filed
Sep 27, 2024
Priority
Sep 27, 2023 — provisional 63/585,814
Examiner
SCHERMERHORN, JON
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Exowatt Inc.
OA Round
2 (Final)
58%
Grant Probability
Moderate
3-4
OA Rounds
1y 3m
Est. Remaining
91%
With Interview

Examiner Intelligence

Grants 58% of resolved cases
58%
Career Allowance Rate
272 granted / 469 resolved
-12.0% vs TC avg
Strong +33% interview lift
Without
With
+33.0%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
19 currently pending
Career history
489
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
49.0%
+9.0% vs TC avg
§102
23.4%
-16.6% vs TC avg
§112
26.2%
-13.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 469 resolved cases

Office Action

§102 §103
DETAILED ACTION Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claims 1-2, 4-6, 9, and 11-13 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by US 11,473,851 B2 (herein “Vuksanovic”). Regarding claim 1. Vuksanovic discloses a thermal storage (Figs. 29 and 30) comprising: an insulative housing (550); at least one thermal storage block (520) disposed within the insulative housing, wherein the at least one thermal storage block is configured such that it can absorb heat provided by one or more thermal concentrators (shown in Fig. 37) through one or more apertures (Fig. 30; apertures through which inlets 530, 531, and 532 pass; heat received at the concentrators is sent through the apertures into storage) defined along a top surface of the insulative housing (the housing can be oriented/rotated such that the inlets 530, 531, and 532 are on the top surface of the housing); and at least one passage defined through the at least one thermal storage block to allow a heat medium to circulate through the at least one thermal storage block (passages shown in Fig. 30, e.g., the passage between 532 and 534). Regarding claim 2. Vuksanovic discloses the thermal storage of claim 1 wherein the at least one thermal storage block comprises an array of thermal storage blocks stacked onto and next to one another (array shown in Figs. 30 and 32). Regarding claim 4. Vuksanovic discloses the thermal storage of claim 1 wherein the insulative housing comprises a double walled housing (col. 19, ln. 59-65; insulation located between walls 514 and 550). Regarding claim 5. Vuksanovic discloses the thermal storage of claim 1 wherein the insulative housing is modular (multiple modules shown in Figs. 29, 30, and 32). Regarding claim 6. Vuksanovic discloses the thermal storage of claim 1 wherein the at least one passage includes an inlet port at a first end of the insulative housing and an exit port also at the first end of the insulative housing (col. 18, ln. 38-40; shown in Fig. 30; 532 is on the same end as 534). Regarding claim 9. Vuksanovic discloses the thermal storage of claim 1 wherein the at least one passage is configured to flow air therethrough (col. 9, ln. 20-21). Regarding claim 11. Vuksanovic discloses the thermal storage of claim 1 wherein the at least one thermal storage block is configured to absorb, along a longitudinal dimension thereof, heat provided by plural spaced-apart thermal concentrators (shown in Fig. 37). Regarding claim 12. Vuksanovic discloses the thermal storage of claim 11 wherein the plural spaced-apart thermal concentrators comprise solar concentrators (title). Regarding claim 13. Vuksanovic discloses the thermal storage of claim 12 wherein the solar concentrators comprise Fresnel lenses (col. 1, ln. 45-60). 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. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1, 3, and 8-14 are rejected under 35 U.S.C. 103 as being unpatentable over Patent No.: US 4,446,850 A (herein “Zilisch”) in view of Pub. No.: US 2025/0341344 A1 (herein “Bisset”). Regarding claim 1. Zilisch discloses a thermal storage (Figs. 1 and 2) comprising: an insulative housing (housing formed by 2, 5, and 6); at least one thermal storage block (8) disposed within the insulative housing, wherein the thermal storage block is configured to absorb heat provided through one or more apertures (solar radiation through aperture at 3) defined along a top surface of the insulative housing (the housing can be oriented such that the aperture is on the top surface); and at least one passage defined through the at least one thermal storage block to allow a heat medium to circulate through the at least one thermal storage block (air passages between 9 and 10). Zilisch does not disclose the use of a solar concentrator. Bisset discloses a solar energy harvesting system which utilizes solar concentrators ([0003]), and it is well known in the art that solar concentrators can be used to enhance the efficiency of solar energy systems by focusing sunlight onto a small area to generate intense heat. Therefore, it would have been obvious to one of ordinary skill in the art to modify the thermal storage of Zilisch with the solar concentrator teachings of Bisset and arrive at the claimed invention. Regarding claim 3. The combined teachings disclose the thermal storage of claim 1 wherein the at least one thermal storage block comprises silicon carbide (Zilisch: col. 16, ln. 50). Regarding claim 8. The combined teachings disclose the thermal storage of claim 1 wherein the at least one thermal storage block comprises a rod bundle (Zilisch: rod bundles 8). Regarding claim 9. The combined teachings disclose the thermal storage of claim 1 wherein the at least one passage is configured to flow air therethrough (Zilisch: col. 4, ln. 53-54). Regarding claim 10. The combined teachings disclose the thermal storage of claim 1 wherein the insulative housing defines a non-contact air gap between the housing and the at least one thermal storage block (Zilisch: shown in Figs. 1 and 2; air gap surrounding rods 8). Regarding claim 11. The combined teachings disclose the thermal storage of claim 1 wherein the at least one thermal storage block is configured to absorb, along a longitudinal dimension thereof, heat provided by plural spaced-apart thermal concentrators (Bisset: shown in Fig. 3C). Regarding claim 12. The combined teachings disclose the thermal storage of claim 11 wherein the plural spaced-apart thermal concentrators comprise solar concentrators (Bisset: title). Regarding claim 13. The combined teachings disclose the thermal storage of claim 12 wherein the solar concentrators comprise Fresnel lenses (Bisset: [0087]). Regarding claim 14. The combined teachings disclose the thermal storage of claim 1 further including an electronic controller that controls forced circulation of a heat carrying medium through the at least one passage (Zilisch: col. 4, ln. 56-58; thermostat 12 may actuate blower 11). Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Zilisch in view of Bisset and CN-209893504-U (herein “Zhang”). Regarding claim 7. The combined teachings disclose the thermal storage of claim 1, but do not disclose an electrical heating element. Zhang discloses a thermal storage including at least one electrical heating element disposed within the insulative housing (abstract; 7). One of ordinary skill in the art would be motivated to modify the thermal storage of the combined teachings with the electrical heating element teachings of Zhang in order to provide additional forms of energy storage in order to store additional energy and/or to allow for continued use of the thermal storage during long periods of reduced solar production, especially in areas that have off peak energy usage hours when energy prices are lowered. Therefore, it would have been obvious to one of ordinary skill in the art to combine the teachings of Zilisch, Bisset, and Zhang and arrive at the claimed invention. Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Vuksanovic in view of Zhang. Regarding claim 7. Vuksanovic discloses the thermal storage of claim 1, but does not disclose an electrical heating element. Zhang discloses a thermal storage including at least one electrical heating element disposed within the insulative housing (abstract; 7). One of ordinary skill in the art would be motivated to modify the thermal storage of Vuksanovic with the electrical heating element teachings of Zhang in order to provide additional forms of energy storage in order to store additional energy and/or to allow for continued use of the thermal storage during long periods of reduced solar production, especially in areas that have off peak energy usage hours when energy prices are lowered. Therefore, it would have been obvious to one of ordinary skill in the art to combine the teachings of Vuksanovic and Zhang and arrive at the claimed invention. Response to Arguments Applicant’s arguments been considered, however, they are made with respect to new limitations added by amendment. In response, Applicant is directed to the rejection above which addresses these new limitations. 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 Jon T. Schermerhorn Jr. whose telephone number is (571)270-5283. The examiner can normally be reached M-F 9am to 5pm. 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. /JON T. SCHERMERHORN JR./Primary Examiner, Art Unit 3763
Read full office action

Prosecution Timeline

Sep 27, 2024
Application Filed
May 06, 2026
Non-Final Rejection mailed — §102, §103
Aug 03, 2026
Response Filed
Oct 06, 2026
Final Rejection mailed — §102, §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
58%
Grant Probability
91%
With Interview (+33.0%)
3y 4m (~1y 3m remaining)
Median Time to Grant
Moderate
PTA Risk
Based on 469 resolved cases by this examiner. Grant probability derived from career allowance rate.

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