Prosecution Insights
Last updated: April 19, 2026
Application No. 18/616,139

COOLING SYSTEMS AND METHODS USING TWO CIRCUITS WITH WATER FLOW IN A COUNTER FLOW AND IN A SERIES OR PARALLEL ARRANGEMENT

Non-Final OA §103§112
Filed
Mar 25, 2024
Examiner
SANKS, SCHYLER S
Art Unit
2129
Tech Center
2100 — Computer Architecture & Software
Assignee
Inertech Ip LLC
OA Round
3 (Non-Final)
72%
Grant Probability
Favorable
3-4
OA Rounds
2y 11m
To Grant
88%
With Interview

Examiner Intelligence

Grants 72% — above average
72%
Career Allow Rate
362 granted / 501 resolved
+17.3% vs TC avg
Strong +16% interview lift
Without
With
+15.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
40 currently pending
Career history
541
Total Applications
across all art units

Statute-Specific Performance

§101
2.6%
-37.4% vs TC avg
§103
46.7%
+6.7% vs TC avg
§102
17.1%
-22.9% vs TC avg
§112
32.2%
-7.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 501 resolved cases

Office Action

§103 §112
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/16/2025 has been entered. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 3-5 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Regarding claim 3, any recitation of “a first main condenser” or “a second main condenser” renders the claim indefinite because it is unclear if antecedence is claimed to the already claimed first and second main condensers of claim 1. Regarding claim 3, “a first side and a second side” is claimed for both “a first main condenser” and “a second main condenser” and it is unclear how these relate to the already claimed “water side” of “a first main condenser” and “a second main condenser” of claim 1. Regarding claim 3, “the ACS evaporator” lacks antecedent basis in the claims. Regarding claim 3, “chilled water supplied by the chiller plant” renders the claim indefinite because it is unclear if this chilled water is the same “chilled-water flow” of claim 1. Regarding claim 4, “the refrigerant” lacks antecedent basis in the claim. Regarding claim 4, “chilled water supplied by the chiller plant” renders the claim indefinite because it is unclear if this chilled water is the same “chilled-water flow” of claim 1 and it is unclear if it is related to the already claimed “chilled water supplied by the chiller plant” of claim 3. Regarding claim 5, the chilled-water flow is stated to be either in series or parallel but claim 1 claims the chilled-water flow as series and therefore it is unclear if claim 5 is broadening the scope of claim 1 or if some other relationship is being claimed as series or parallel. Claim 4 is indefinite by virtue of dependency on claim 3. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. 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. 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. Claim(s) 1-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Keisling (US20120127657A1) in view of Ding (US20120103009A1). Regarding claim 1, Keisling teaches a cooling system comprising: a first evaporator coil in thermal communication with an air intake flow to a heat load (Figure 3: 23, ¶98); a first liquid refrigerant distribution unit in fluid communication with the first evaporator coil to form a first fluid circuit (Figure 7: 4002); a second evaporator coil disposed in series with the first evaporator coil in the air intake flow and in thermal communication with the air intake flow to the heat load (Figure 3: 533 ¶98); a second liquid refrigerant distribution unit in fluid communication with the second evaporator coil to form a second fluid circuit (Figure 7: 4001); a water circuit in thermal communication with the first fluid circuit and second fluid circuit (Figure 5: 4200, see Figure 7, where 4200 feeds water to each circuit, ¶133); and a chiller circuit in thermal communication with the water circuit (¶132), wherein the chiller circuit includes a chiller plant configured to supply chilled water directly to the water circuit (¶132), wherein the water circuit directs a chilled-water flow from the chiller plant first through a water side of a first main condenser of the first fluid circuit (¶132, Figure 6, 4200a to 1300) and through a water side of a second main condenser of the second fluid circuit (¶132, Figure 7, 4001), and wherein the first and second evaporator coils arranged in series with the air intake flow cooperate with the first and second main condensers, thereby providing staged cooling of the air intake flow (Figure 3: 533 and 23). Keilsing does not teach wherein the chilled-water flow from the chiller plant flows through the first main condenser and subsequently though a water side of a second main condenser of the second fluid circuit in a series, counter-flow arrangement where the first fluid circuit is maintained at a lower refrigerant saturation temperature than the second fluid circuit. Ding teaches utilizing a first main condenser (Figure 3: 230) through which chilled-water flow flows to cool the condenser (Figure 3: “COOLING WATER IN”) and subsequently the chilled-water flow flows through a second main condenser (Figure 3: 130) in a series, counterflow arrangement (¶42, and/or see Figure 3, 230) wherein the first fluid circuit is maintained at a lower refrigerant saturation temperature than the second fluid circuit (240 is at a lower temperature than 140, i.e. it is able to absorb more heat from the flow at a lower temperature than 140) which increases capacity (¶4). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Keisling such that the chilled-water flow from the chiller plant flows through the first main condenser and subsequently though a water side of a second main condenser of the second fluid circuit in a series, counter-flow arrangement where the first fluid circuit is maintained at a lower refrigerant saturation temperature than the second fluid circuit in order to increase cooling capacity and/or provide more cooling power. Regarding claim 2, Keisling as modified teaches all of the limitations of claim 1, wherein the first and second evaporator coils are microchannel evaporator coils (¶105). Regarding claim 3, Keisling as modified teaches all of the limitations of claim 1, wherein a compressor in fluid communication with the fluid output of the first side of the ACS evaporator and with the fluid input of the first side of the trim condenser (figure 6: 4310, 4300a), wherein the first fluid circuit includes a first main condenser having a first side and a second side (Figure 6: 1300), a first fluid receiver in fluid communication with the first side of the first main condenser (Figure 6: 4128), and a refrigerant pump in fluid communication with the first fluid receiver (Figure 6: 4120), the second side of the first main condenser being in fluid communication with the second side of the ACS evaporator (Figure 6: 4200f to 4211 to 1300), wherein the second fluid circuit includes a second main condenser having a first side and a second side (Figure 6: 1300), a second fluid receiver in fluid communication with the first side of the second main condenser (Figure 6: 4128), and a refrigerant pump in fluid communication with the second fluid receiver (Figure 6: 4120), the second side of the second main condenser being in fluid communication with the second side of the first main condenser and the water circuit (Figure 7: 4201a/m and 4202a/m are both in fluid communication with 2152a/2151b and therefore in fluid communication with each other and therefore the second sides of the main condensers are in fluid communication with each other), and wherein the water circuit is in fluid communication with sides of the first and second main condensers (see rejection of claim 1) and receives chilled water supplied by the chiller plant (Figure 6, see rejection of claim 1). Regarding claim 4, Keisling as modified teaches all of the limitations of claim 3, wherein chilled water supplied by the chiller plant is in thermal communication with the first and second fluid circuits (see rejection of claim 1), and wherein the chilled water and the refrigerant flowing through the first and second fluid circuits are in thermal counter flow (Figure 6: 1200a and 1300 show counterflow arrangements). Regarding claim 5, Keisling teaches all of the limitations of claim 3, wherein the chilled-water flows through the first and the second main condensers in a series or in a parallel arrangement (see rejection of claim 1). Regarding claim 6, Keisling teaches a method of cooling a heat load using a dual-circuit cooling system, the method comprising: directing an air intake flow from a heat load through a second evaporator coil and subsequently through a first evaporator coil (Figure 3: 533 to 23, ¶98); circulating a first liquid refrigerant through a first fluid circuit comprising the first evaporator coil and a first main condenser (Figure 7: 4002, 4100, ¶125); circulating a second liquid refrigerant through a second fluid circuit comprising the second evaporator coil and a second main condenser (Figure 7: 4001, 4100, ¶125); and pumping a water flow from a cooling source through the first main condenser to condense the first liquid refrigerant (Figure 7: 4202a) and through the second main condenser to condense the second liquid refrigerant (Figure 7: 4201a). Keilsing does not teach wherein the water flow from the source flows through the first main condenser and subsequently through the second main condenser wherein the water flow absorbs heat from the first fluid circuit before absorbing heat from the second fluid circuit. Ding teaches utilizing a first main condenser (Figure 3: 230) through which water flows to cool the first main condenser (Figure 3: “COOLING WATER IN”) and subsequently the water flows through a second main condenser (Figure 3: 130) wherein the water flow absorbs heat from the first fluid circuit before absorbing heat from the second fluid circuit than (“COOLING WATER IN” to “COOLING WATER OUT”) which increases capacity (¶4). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Keisling such that the water flow from the source flows through the first main condenser and subsequently through the second main condenser wherein the water flow absorbs heat from the first fluid circuit before absorbing heat from the second fluid circuit.in order to increase cooling capacity and/or provide more cooling power. Regarding claim 7, Keisling as modified teaches all of the limitations of claim 6, further comprising maintaining a refrigerant saturation temperature of the first fluid circuit at a lower temperature than a refrigerant saturation temperature of the second fluid circuit (see rejection of claim 6 and Ding, 240 is at a lower temperature than 140, i.e. it is able to absorb more heat from the flow at a lower temperature than 140). Regarding claim 8, Keisling as modified teaches all of the limitations of claim 7, but does not teach wherein the refrigerant saturation temperature of the first fluid circuit is maintained at approximately 24 C and the refrigerant saturation temperature of the second fluid circuit is maintained at approximately 31 C. Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical, MPEP 2144.05, II, A. In the instant case, claim 8 recites a difference in temperature from the prior art; the prior art device of Keisling provides two saturation temperatures (see rejection of claim 7) but does not specify them as in claim 8. Where the general conditions of a claim are disclosed in the prior art, as in Keisling as modified, it is not inventive to discover the optimum or workable ranges by routine experimentation. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize 24 degrees Celsius as the saturation temperature for the first fluid circuit and 31 degrees Celsius as the saturation temperature for the second fluid circuit in Keisling as modified in order to achieve the staged cooling of Keisling as modified. Regarding claim 9, Keisling as modified teaches all of the limitations of claim 6, wherein the cooling source comprises a chiller plant (¶132), and the method further comprises receiving chilled water from the chiller plant at an input of the first main condenser and returning the water flow to the chiller plant from an output of the second main condenser (¶132, see Figure 7 where return water flows back to the chiller plant and in the case of Keisling as modified it would flow as claimed, see rejection of claim 1). Regarding claim 10, Keisling as modified teaches all of the limitations of claim 6, further comprising operating the cooling system in a backup mode (¶167). The limitation “if one of the first fluid circuit or the second fluid circuit fails to operate, the other fluid circuit continues to cool the heat load” is not required under the broadest reasonable interpretation of the claim, see MPEP 2111.04. Notwithstanding, Keisling as modified teaches if one of the first fluid circuit or the second fluid circuit fails to operate, the other fluid circuit continues to cool the heat load (see Figure 7, circuits are siloed such that if one were to fail the others may still operate). Regarding claim 11, Keisling as modified teaches all of the limitations of claim 6, wherein the first and second evaporator coils comprise microchannel evaporator coils (¶105). Regarding claim 12, Keisling as modified teaches all of the limitations of claim 6, further comprising controling a flow rate of the water flow to increase an energy efficiency of the dual-circuit cooling system. Regarding claim 13, Keisling teaches a cooling system comprising: a first liquid refrigerant distribution unit forming a first fluid circuit, the first fluid circuit including a first main condenser and a first evaporator coil (Figure 7: 4002 with 23 and condenser 1300, see Figure 6); a second liquid refrigerant distribution unit forming a second fluid circuit, the second fluid circuit including a second main condenser and a second evaporator coil Figure 7: 4001 with 533 and condenser 1300, see Figure 6, wherein the first and second evaporator coils are arranged in series in an air path of a heat load (Figure 3: 533 and 23); and a connection to a chiller plant, wherein an output of the chiller plant is in fluid communication with an input of a water side of the first main condenser, and an output of a water side of the second main condenser is in fluid communication with an input of the chiller plant (Figure 7: 4202a and 4201m, ¶132), such that chilled water from the chiller plant flows through the first main condenser and through the second main condenser (Figure 7: 4202a and 4201m, ¶132). Keilsing does not teach wherein the water flow from the chiller plant flows through the first main condenser and subsequently through the second main condenser. Ding teaches utilizing a first main condenser (Figure 3: 230) through which water flows to cool the first main condenser (Figure 3: “COOLING WATER IN”) and subsequently the water flows through a second main condenser (Figure 3: 130) wherein the water flow absorbs heat from the first fluid circuit before absorbing heat from the second fluid circuit than (“COOLING WATER IN” to “COOLING WATER OUT”) which increases capacity (¶4). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Keisling such that the water flow from the source flows through the first main condenser and subsequently through the second main condenser wherein the water flow absorbs heat from the first fluid circuit before absorbing heat from the second fluid circuit.in order to increase cooling capacity and/or provide more cooling power. Regarding claim 14, Keisling as modified teaches all of the limitations of claim 13, wherein the chiller plant replaces a local water loop and a local chiller loop (Figure 7, ¶132, a chiller plant is used instead of a local water loop and a local chiller loop so it “replaces” them). Regarding claim 15, Keisling as modified teaches all of the limitations of claim 13, wherein the chilled water flows through the first and second main condensers in a thermal counter flow arrangement relative to the air path of the heat load (see rejection of claim 13 – air flows from 533 to 23 but chilled water would flow from the circuit with 23 to the circuit with 533). Regarding claim 16, Keisling as modified teaches all of the limitations of claim 13, wherein the chiller plant provides chilled water to refrigerant distribution units including the first and second liquid refrigerant distribution units (Figure 7, 4001-4003, ¶132). Regarding claim 17, Keisling as modified teaches all of the limitations of claim 13, wherein the first and second evaporator coils are mounted on a rear door or a top of a computer server cabinet (Figure 3: 533 and 23, 23 is on top of a cabinet and 533a can be considered to be on the top of a cabinet or on a rear door of the cabinet). Regarding claim 18, Keisling as modified teaches all of the limitations of claim 13, wherein the water side of the second main condenser is connected to the water side of the first main condenser in a series arrangement (see rejection of claim 13). Regarding claim 19, Keisling as modified teaches all of the limitations of claim 13, further comprising a pump configured to circulate the chilled water through the first and second main condensers (¶51). Regarding claim 20, Keisling as modified teaches all of the limitations of claim 13, wherein the first and second evaporator coils are microchannel evaporator coils (¶105). Response to Arguments Applicant’s arguments filed 12/16/2025 have been fully considered. Applicant has argued that Keisling does not teach the subsequent flow through first and second condensers. Keisling is not relied upon to teach these features and therefore the argument is moot. In general, the arguments are moot in view of the new grounds of rejection. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to SCHYLER S SANKS whose telephone number is (571)272-6125. The examiner can normally be reached 06:30 - 15:30 Central Time, 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, Michael Huntley can be reached at (303) 297-4307. 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. /SCHYLER S SANKS/Primary Examiner, Art Unit 2129
Read full office action

Prosecution Timeline

Mar 25, 2024
Application Filed
Nov 26, 2024
Non-Final Rejection — §103, §112
Jun 02, 2025
Response Filed
Jul 14, 2025
Final Rejection — §103, §112
Dec 16, 2025
Request for Continued Examination
Dec 31, 2025
Response after Non-Final Action
Jan 09, 2026
Non-Final Rejection — §103, §112 (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
72%
Grant Probability
88%
With Interview (+15.9%)
2y 11m
Median Time to Grant
High
PTA Risk
Based on 501 resolved cases by this examiner. Grant probability derived from career allow rate.

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