Prosecution Insights
Last updated: April 19, 2026
Application No. 18/080,391

METHOD OF VARYING DEFROST TRIGGER FOR HEAT PUMP

Non-Final OA §102§103
Filed
Dec 13, 2022
Examiner
MARTIN, ELIZABETH J
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Carrier Corporation
OA Round
3 (Non-Final)
78%
Grant Probability
Favorable
3-4
OA Rounds
2y 7m
To Grant
99%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
729 granted / 930 resolved
+8.4% vs TC avg
Strong +21% interview lift
Without
With
+20.8%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
28 currently pending
Career history
958
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
47.8%
+7.8% vs TC avg
§102
21.6%
-18.4% vs TC avg
§112
27.3%
-12.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 930 resolved cases

Office Action

§102 §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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 11/18/2025 has been entered. Status This Office Action is in response to the remarks and amendments filed on 11/18/2025. Claims 1, 3-7, 9-20 remain pending for consideration on the merits. It is noted that claim 19 appears to be missing limitations after “initiating a defrost mode when the heating”. Claim Rejections - 35 USC § 102 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1, 3-4, 7, 9-10 is/are rejected under 35 U.S.C. 102(a)(1) as being Ishimura et al by (US 20220107123). Regarding claims 1 and 19, Ishimura teaches a method for determining when to initiate a defrost mode of a heat pump (100), the method comprising: monitoring a heating capacity (ST2, paragraph 0052) of an evaporator (4-1, 4-2) of the heat pump during operation of the heat pump in a heating mode (fig. 5) via monitoring at least one parameter or operating condition (evaporating temperature, paragraph 0052, fig. 2) of the heat pump associated with the heating capacity (paragraph 0052) wherein monitoring at least one parameter or operating condition of the heat pump associated with the heating capacity includes measuring at least one of a temperature and pressure at an inlet of the evaporator (92-1, 92-2, The controller 90 determines an evaporating temperature Te converted based on pressures measured by the outdoor pressure sensors 92-1 and 92-2 and the controller 90 calculates a refrigerant flow rate in the normal heating operation on the basis of an evaporating pressure converted from the evaporating temperature Te paragraph 0039); determining a threshold (an evaporating temperature threshold, paragraph 0052) associated with the heating capacity (ST2); wherein determining the threshold associated with the heating capacity includes identifying a reference value (an evaporating temperature, paragraph 0052) associated with the heating capacity; and deriving, via a controller (90), the threshold from the reference value (paragraph 0052, the controller 90 determines whether an evaporating temperature of the refrigerant flowing through the parallel heat exchangers 4-1 and 4-2 is less than an evaporating temperature threshold (step ST2). For example, in response to determining that the evaporating temperature is less than the evaporating temperature threshold, the controller 90 determines that frost is accumulated on the parallel heat exchangers 4-1 and 4-2, and shifts the operation mode to the heating-defrosting operation mode (step ST3); and initiating a defrost mode (ST3) when the heating capacity of the evaporator is less than or equal to the threshold (paragraph 0052). Further, it is understood, claim 19 includes an intended use recitation, for example “…configured to...”. The applicant is reminded that a recitation with respect to the manner which a claimed apparatus is intended to be does not differentiate the claimed apparatus from a prior art apparatus satisfying the structural limitations of the claims, as is the case here. While features of an apparatus may be recited either structurally or functionally, the claims are directed to an apparatus must be distinguished from the prior art in terms of structure rather than function. Regarding claim 5, Ishimura teaches the at least one parameter or operating condition comprises at least one of a pressure at an inlet of the evaporator (92-1, 92-2, The controller 90 determines an evaporating temperature Te converted based on pressures measured by the outdoor pressure sensors 92-1 and 92-2 and the controller 90 calculates a refrigerant flow rate in the normal heating operation on the basis of an evaporating pressure converted from the evaporating temperature Te paragraph 0039). Regarding claim 20, Ishimura teaches comprising at least one sensor (92-1, 92-2, The controller 90 determines an evaporating temperature Te converted based on pressures measured by the outdoor pressure sensors 92-1 and 92-2 and the controller 90 calculates a refrigerant flow rate in the normal heating operation on the basis of an evaporating pressure converted from the evaporating temperature Te paragraph 0039) to operably coupled to the controller, the sensor being configured to monitor at least one parameter or operating condition of the heat pump associated with the heating capacity (92-1, 92-2, The controller 90 determines an evaporating temperature Te converted based on pressures measured by the outdoor pressure sensors 92-1 and 92-2 and the controller 90 calculates a refrigerant flow rate in the normal heating operation on the basis of an evaporating pressure converted from the evaporating temperature Te paragraph 0039). Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 3-4, 9-10, 12-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ishimura as applied to claim 1 in view of Tanaka (US 2020043392). Regarding claim 3, Ishimura teaches the invention as described above but fails to explicitly teach wherein the parameter or operating condition is a refrigerant mass flow. However, Tanaka teaches wherein the parameter or operating condition is a refrigerant mass flow (paragraph 0052, pressure Ps of the refrigerant suctioned into compressor 1, the temperature of the refrigerant suctioned into compressor 1 or the temperature of the refrigerant at the outlet of outdoor heat exchanger 6 is decreased, one of ordinary skill would recognize a decrease in pressure would reflect refrigerant mass flow) to efficiently defrost an outdoor heat exchanger. Therefore, it would have been obvious to a person skilled in the art at the time of the invention to modify the heat pump of Ishimura to include the parameter or operating condition is a refrigerant mass flow in view of the teachings of Tanaka to efficiently defrost an outdoor heat exchanger. Regarding claim 4, the combined teachings teach the at least one parameter or operating condition comprises at least a pressure at an inlet of a compressor arranged directly downstream from the evaporator relative to a fluid flow through the heat pump in the heating mode, and a pressure between the outlet of the evaporator and the inlet of the compressor (paragraph 0052 of Tanaka). Regarding claim 9, the combined teachings teach identifying the reference value further comprises measuring a parameter or operating condition of the heat pump associated with the heating capacity when the evaporator is free of frost (paragraph 0075 of Tanaka). Regarding claim 10, the combined teachings teach teaches the evaporator is free of frost at a beginning of the heating cycle (paragraph 0077 of Tanaka, understood there would be no frost at the switch from defrosting operation to heating operation). Regarding claim 12, the combined teachings teach adjusting the reference value to compensate for changes in one or more operating conditions of the heat pump during the heating mode (Col. 5, 24-67 of Tanaka). Regarding claim 13, the combined teachings teach determining the threshold comprises at least one of (ii) applying an offset to the reference value (Col. 5, 24-67 of Tanaka). Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ishimura as applied to claim 1 in view of Wei et al (US 20150159935). Regarding claim 6, Ishimura teaches the invention as described above but fails to explicitly teach the at least one parameter or operating condition comprises a temperature at an outlet of an expansion device, the expansion device being arranged directly upstream from the evaporator relative to a fluid flow through the heat pump in the heating mode. However, Wei teaches the at least one parameter or operating condition comprises a temperature (16) at an outlet of an expansion device (130), the expansion device being arranged directly upstream from the evaporator relative to a fluid flow through the heat pump in the heating mode (fig. 2) to effectively performing a defrosting process without causing temperature to drop. Therefore, it would have been obvious to a person skilled in the art at the time of the invention to modify the heat pump of Ishimura to include at least one parameter or operating condition comprises a temperature at an outlet of an expansion device, the expansion device being arranged directly upstream from the evaporator relative to a fluid flow through the heat pump in the heating mode in view of the teachings of Wei to effectively performing a defrosting process without causing temperature to drop. Claim(s) 7, 14-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ishimura as applied to claim 1 in view of Ishikawa et al (US 20140090406). Regarding claim 7, Ishimura teaches the invention as described above but fails to explicitly teach the at least one parameter or operating condition comprises a temperature of an air discharged from the evaporator. However, Ishikawa teaches the at least one parameter or operating condition comprises a temperature of an air discharged from the evaporator (12a, paragraph 0025) to efficiently measure the air discharged from the outdoor heat exchanger. Therefore, it would have been obvious to a person skilled in the art at the time of the invention to modify the heat pump of Ishimura to include the at least one parameter or operating condition comprises a temperature of an air discharged from the evaporator in view of the teachings of Ishiwaka to efficiently measure the air discharged from the outdoor heat exchanger. Regarding claim 14, the combined teachings teach prohibiting initiation in the defrost mode in response to a cumulative time of operation of a compressor of the heat pump since operation of the heat pump in the defrost mode being less than a minimum time (each of the refrigeration cycles is prevented from performing the defrosting operation for a predetermined period of time from a time at which any one of the refrigeration cycles returned to the heating operation from the defrosting operation, paragraph 0040 of Ishiwaka). Regarding claim 15, the combined teachings teach prohibiting initiation in the defrost mode for a fixed period of time once a compressor of the heat pump beings operating after being in an idle condition (paragraph 0040 of Ishiwaka). Regarding claim 16, the combined teachings teach prohibiting initiation in the defrost mode when a rate of change of the parameter or operating condition indicates transient operating conditions (paragraph 0040 of Ishiwaka). Regarding claim 17, the combined teachings teach prohibiting initiation in the defrost mode when a rate of change of the parameter or operating condition exceeds a positive threshold or falls below a negative threshold (paragraph 0040 of Ishiwaka). Regarding claim 18, the combined teachings teach prohibiting initiation in the defrost mode when a rate of change of the parameter or operating condition is between a positive threshold and a negative threshold for less than a threshold period of time after the rate of change of the parameter was either above the positive threshold or below the negative threshold (paragraph 0040 of Ishiwaka). Claim(s) 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ishimura as applied to claim 1 in view of Alsenz (US 5428966). Regarding claim 11, Ishimura teaches the invention as described above but fails to explicitly teach identifying the reference value further comprises looking up the reference value in a table. However, Alsenz teaches identifying the reference value further comprises looking up the reference value in a table (look-up tables, Col. 5, 59-67) to efficiently optimize the refrigeration system. Therefore, it would have been obvious to a person skilled in the art at the time of the invention to modify the heat pump of Ishimura to include identifying the reference value further comprises looking up the reference value in a table in view of the teachings of Alsenz to efficiently optimize the refrigeration system. Response to Arguments Applicant’s arguments with respect to 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. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ELIZABETH J MARTIN whose telephone number is (571)270-3840. The examiner can normally be reached 8:30-3:00 CT pm M-F. 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, Jerry-Daryl Fletcher can be reached on (571) 270-5054. 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. /ELIZABETH J MARTIN/Primary Examiner, Art Unit 3763
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Prosecution Timeline

Dec 13, 2022
Application Filed
Jan 14, 2025
Non-Final Rejection — §102, §103
Apr 17, 2025
Response Filed
Jul 15, 2025
Final Rejection — §102, §103
Oct 17, 2025
Response after Non-Final Action
Nov 18, 2025
Request for Continued Examination
Dec 03, 2025
Response after Non-Final Action
Dec 03, 2025
Non-Final Rejection — §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
78%
Grant Probability
99%
With Interview (+20.8%)
2y 7m
Median Time to Grant
High
PTA Risk
Based on 930 resolved cases by this examiner. Grant probability derived from career allow rate.

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