Prosecution Insights
Last updated: April 19, 2026
Application No. 18/683,488

LIQUID DESICCANT ABSORPTION CHILLER

Final Rejection §103
Filed
Feb 13, 2024
Examiner
TADESSE, MARTHA
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Nortek Air Solutions Canada, Inc.
OA Round
2 (Final)
66%
Grant Probability
Favorable
3-4
OA Rounds
3y 3m
To Grant
81%
With Interview

Examiner Intelligence

Grants 66% — above average
66%
Career Allow Rate
410 granted / 618 resolved
-3.7% vs TC avg
Strong +15% interview lift
Without
With
+15.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
39 currently pending
Career history
657
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
53.2%
+13.2% vs TC avg
§102
13.7%
-26.3% vs TC avg
§112
30.6%
-9.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 618 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 . Information Disclosure Statement The information disclosure statement (IDS) submitted on 11/10/2025 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner. 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 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 of this title, 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. Claims 1, 3, 10-15, 18-20 and 22 are rejected under pre-AlA 35 U.S.C. 103 as being unpatentable over Heinzl (US 20130298590) in view of Tang et al. (US 2012/0240605). In regards to claim 1, Heinzl discloses an absorber-evaporator (an apparatus 10; Figs. 2-3) comprising: a cooling liquid channel (channel 26) through which a cooling liquid (a cooling fluid) is configured to flow; a liquid desiccant channel (channel 36) through which a liquid desiccant (hygroscopic solution 14) is configured to flow; an enclosed air-gap cell (a gas flow passage 18) disposed between the cooling liquid channel (26) and the liquid desiccant channel (36); a first permeable membrane (left membrane wall 24) disposed between the liquid desiccant channel (36) and the air-gap cell (18); and a second permeable membrane (right membrane wall 24) disposed between the cooling liquid channel (26) and the air-gap cell (18), and vapor (water vapor) separated from the cooling liquid (a cooling fluid) is configured to pass through the first membrane (left 24) and the second membrane (right 24) via the enclosed air-gap cell (18) to be absorbed by the liquid desiccant (14), (refer to par. 44), but fails to explicitly teach wherein: a pressure in the enclosed air-gap cell is selectively controlled. Tang teaches thermal energy management system (100) wherein: a pressure in the enclosed air-gap cell is selectively controlled (via valves 114; par. 18). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that a pressure in the enclosed air-gap cell is selectively controlled as taught by Tang in order to allow thermal energy to be passed between the combined absorbent/refrigerant (refer to par. 18 of Tang). In regards to claim 3, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 1, but fails to explicitly teach wherein: the cooling liquid channel comprises a plurality of evaporation chambers fluidically connected to one another in series and defining a cooling liquid channel flow path along which the cooling liquid flows through the cooling liquid channel. Tang teaches thermal energy management system (100) wherein: the cooling liquid channel (left side conduits 112) comprises a plurality of evaporation chambers (evaporation chambers 106a-d) fluidically connected to one another in series and defining a cooling liquid channel flow path (left conduits 110a-d) along which the cooling liquid (refrigerant 134) flows through the cooling liquid channel (Figs. 1-2). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that the cooling liquid channel comprises a plurality of evaporation chambers fluidically connected to one another in series and defining a cooling liquid channel flow path along which the cooling liquid flows through the cooling liquid channel as taught by Tang in order to allow thermal energy to be transferred from the concentrated solution to the diluted solution (refer to par. 20 of Tang). In regards to claim 10, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 3. Further, Tang teaches wherein: the air-gap cell comprises a plurality of air-gap chambers (air gaps space in between evaporation chambers 106a-d) each of which corresponds with one of the plurality of evaporation chambers (evaporation chambers 106a-d) and one of the plurality of absorption chambers (absorption chambers 108b-d) to define an evaporation stage in which vapor separated from the cooling liquid passes from the evaporation chamber (evaporation chambers 106a-d) through the first membrane (24 of Heinzl) and the second membrane (24 of Heinzl) via the air-gap chamber (18 of Heinzl) to be absorbed by the liquid desiccant (par. 44 of Heinzl). In regards to claim 11, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 10, but fails to explicitly teach wherein: the plurality of air-gap chambers of the air-gap cell are configured such that one or more parameters in each of the plurality of air-gap chambers are independently controllable. Tang teaches thermal energy management system (100) wherein: the plurality of air-gap chambers (air gap) of the air-gap cell are configured such that one or more parameters in each of the plurality of air-gap chambers (air gap; par. 120) are independently controllable (by reducing the air gap near the exit of the membrane plates, the surface velocity of the air over the membranes can be held constant; par. 120). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that the plurality of air-gap chambers of the air-gap cell are configured such that one or more parameters in each of the plurality of air-gap chambers are independently controllable as taught by Tang in order to allow a more optimum efficiency along the membrane surface (refer to par. 120 of Tang). In regards to claim 12, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 10. Further, Heinzl teaches wherein: the one or more parameters comprises air pressure (temperature corresponding to the absolute pressure in the vapor space of a respective adjacent evaporator unit over all stages; refer to par. 25). In regards to claim 13, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 10, but fails to explicitly teach wherein: the plurality of evaporation chambers of the cooling liquid channel are configured such that one or more parameters in each of the plurality of evaporation chambers are independently controllable. Tang teaches thermal energy management system (100) wherein: the plurality of evaporation chambers (evaporation chambers 106a-d) of the cooling liquid channel (left conduit 112) are configured such that one or more parameters (flow of evaporated refrigerant) in each of the plurality of evaporation chambers (106a-d) are independently controllable (refer to par. 35). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that the plurality of evaporation chambers of the cooling liquid channel are configured such that one or more parameters in each of the plurality of evaporation chambers are independently controllable as taught by Tang in order to receive and cause therein evaporation of said refrigerant (refer to par. 8 of Tang). In regards to claim 14, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 10, but fails to explicitly teach wherein: the plurality of absorption chambers of the liquid desiccant channel are configured such that one or more parameters in each of the plurality of absorption chambers are independently controllable. Tang teaches thermal energy management system (100) wherein: wherein: the plurality of absorption chambers (absorption chambers 108b-d) of the liquid desiccant channel are configured such that one or more parameters (flow of evaporated refrigerant) in each of the plurality of absorption chambers (108b-d) are independently controllable (refer to par. 35). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that the plurality of absorption chambers of the liquid desiccant channel are configured such that one or more parameters in each of the plurality of absorption chambers are independently controllable as taught by Tang in order to cause absorbent to crystallize in the second of the absorption chambers (refer to par. 8 of Tang). In regards to claim 15, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 1. Further, Heinzl teaches an apparatus (10) wherein: a vapor pressure of the cooling liquid in the cooling liquid channel is greater than a vapor pressure of the liquid desiccant in the liquid desiccant channel (refer to par. 85). In regards to claim 18, Heinzl discloses a liquid desiccant absorption chiller (an apparatus 10; Figs. 2-3) comprising: an absorber-evaporator (absorption device 16) comprising: a cooling liquid channel (channel 26) through which a cooling liquid (a cooling fluid) is configured to flow; a liquid desiccant channel (channel 36) through which a liquid desiccant (hygroscopic solution 14) is configured to flow; an enclosed air-gap cell (a gas flow passage 18) disposed between the cooling liquid channel (26) and the liquid desiccant channel (36); a first permeable membrane (left membrane wall 24) disposed between the liquid desiccant channel (36) and the air-gap cell (18); and a second permeable membrane (right membrane wall 24) disposed between the cooling liquid channel (26) and the air-gap cell (18); and a regenerator (a regeneration device 28) configured to receive and regenerate dilute liquid desiccant from and return concentrated liquid desiccant to the absorber-evaporator (refer to par. 82), wherein: vapor (water vapor) separated from the cooling liquid (a cooling fluid) is configured to pass through the first membrane (left 24) and the second membrane (right 24) via the enclosed air-gap cell (18) to be absorbed by the liquid desiccant (14), (refer to par. 44), but fails to explicitly teach wherein: a pressure in the enclosed air-gap cell is selectively controlled. Tang teaches thermal energy management system (100) wherein: a pressure in the enclosed air-gap cell is selectively controlled (via valves 114; par. 18). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that a pressure in the enclosed air-gap cell is selectively controlled as taught by Tang in order to allow thermal energy to be passed between the combined absorbent/refrigerant (refer to par. 18 of Tang). In regards to claim 19, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 18. Further, Vandermeulen teaches wherein: the first and second permeable membranes (303) are configured to permeate gas and vapor and to prevent permeation of liquids and solids (refer to par. 7). In regards to claim 20, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 18. Further, Tang teaches wherein: the cooling liquid channel (left side conduits 112) comprises a plurality of evaporation chambers (evaporation chambers 106a-d) fluidically connected to one another in series and defining a cooling liquid channel flow path (left conduits 110a-d) along which the cooling liquid (refrigerant 134) flows through the cooling liquid channel (Figs. 1-2). In regards to claim 22, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 20. Further, Tang teaches wherein: the liquid desiccant channel (right side conduits 112) comprises a plurality of absorption chambers (absorption chambers 108b-d) fluidically connected to one another in series and defining a liquid desiccant channel flow path (right conduits 110a-d) along which the liquid desiccant (absorbent-refrigerant solution 130) flows through the liquid desiccant channel (Figs. 1-2). Claims 2, 4-9 and 16-17 are rejected under pre-AlA 35 U.S.C. 103 as being unpatentable over Heinzl (US 20130298590) in view of Tang et al. (US 2012/0240605), further in view of in view of Vandermeulen (US 2014/0150656). In regards to claim 2, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 1. Further, Heinzl teaches wherein: the first (left 24) and second permeable membranes (right 24), but fails to explicitly teach permeable membranes are configured to permeate gas and vapor and to prevent permeation of liquids and solids. Vandermeulen teaches a similar apparatus wherein: the permeable membranes (603) are configured to permeate gas and vapor and to prevent permeation of liquids and solids (refer to par. 110; Fig. 10). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl to include permeable membranes that are configured to permeate gas and vapor and to prevent permeation of liquids and solids as taught by Vandermeulen in order to ensures that there are no areas or spots of liquid desiccant breaking through the membrane (refer to par. 110 of Tang). In regards to claim 4, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 3, but fails to explicitly teach wherein: the cooling liquid channel flow path is a serpentine flow path. Vandermeulen teaches wherein: the cooling liquid channel flow path is a serpentine flow path (fluid path 1582; Fig. 48-51). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that the cooling liquid channel flow path to be a serpentine flow path as taught by Vandermeulen in order to create turbulent mixing in the cooling fluid while maintaining uniform cooling fluid flow patterns (refer to par. 146 of Vandermeulen). In regards to claim 5, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 4, but fails to explicitly teach wherein: the liquid desiccant channel comprises a plurality of absorption chambers fluidically connected to one another in series and defining a liquid desiccant channel flow path along which the liquid desiccant flows through the liquid desiccant channel. Tang teaches thermal energy management system (100) wherein: the liquid desiccant channel (right side conduits 112) comprises a plurality of absorption chambers (absorption chambers 108b-d) fluidically connected to one another in series and defining a liquid desiccant channel flow path (right conduits 110a-d) along which the liquid desiccant (absorbent-refrigerant solution 130) flows through the liquid desiccant channel (Figs. 1-2). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that the liquid desiccant channel comprises a plurality of absorption chambers fluidically connected to one another in series and defining a liquid desiccant channel flow path along which the liquid desiccant flows through the liquid desiccant channel as taught by Tang in order to allow thermal energy to be transferred from the concentrated solution to the diluted solution (refer to par. 20 of Tang). In regards to claim 6, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 5, but fails to explicitly teach wherein: the cooling liquid channel flow path is a serpentine flow path. Vandermeulen teaches wherein: the cooling liquid channel flow path is a serpentine flow path (fluid path 1582; Fig. 48-51). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that the cooling liquid channel flow path to be a serpentine flow path as taught by Vandermeulen in order to create turbulent mixing in the cooling fluid while maintaining uniform cooling fluid flow patterns (refer to par. 146 of Vandermeulen). In regards to claim 7, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 6, but fails to explicitly teach the cooling liquid flows through the serpentine flow path of the cooling liquid channel in a direction opposite a direction of flow of the liquid desiccant flowing through the serpentine flow path of the liquid desiccant channel. Vandermeulen teaches wherein: the cooling liquid flows through the serpentine flow path (fluid path 1582; Fig. 48-51) of the cooling liquid channel (306) in a direction opposite a direction of flow of the liquid desiccant flowing through the serpentine flow path of the liquid desiccant channel (refer to Fig. 8). It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that the cooling liquid flows through the serpentine flow path of the cooling liquid channel in a direction opposite a direction of flow of the liquid desiccant flowing through the serpentine flow path of the liquid desiccant channel as taught by Vandermeulen in order to create turbulent mixing in the cooling fluid while maintaining uniform cooling fluid flow patterns (refer to par. 146 of Vandermeulen). In regards to claim 8, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 5. Further, Vandermeulen teaches wherein: the serpentine flow path (fluid path 1582; Fig. 48-51) of the liquid desiccant channel (304/503) directs the liquid desiccant (desiccant fluid) in first and second opposite directions through adjacent absorption chambers of the plurality of absorption chambers (as can be seen Figs. 7-9), but fails to explicitly teach a third direction between adjacent absorption chambers of the plurality of absorption chambers; and the third direction is perpendicular to the first and second opposing directions. Tang teaches thermal energy management system (100; Figs. 1-2) wherein a third direction (direction of conduit 110) between adjacent absorption chambers (absorption chambers 108b-d) of the plurality of absorption chambers (absorption chambers 108b-d); and the third direction is perpendicular (as can be seen in Figs. 1-2) to the first (direction of stream 134) and second (direction of stream 132) opposing directions. It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that a third direction between adjacent absorption chambers of the plurality of absorption chambers; and the third direction is perpendicular to the first and second opposing directions as taught by Tang in order to allow a more optimum efficiency along the membrane surface (refer to par. 120 of Tang). In regards to claim 9, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 4. Further, Vandermeulen teaches The absorber-evaporator of claim 4, wherein: the serpentine flow path (fluid path 1582; Fig. 48-51) of the cooling liquid channel (306/502) directs the cooling liquid (cooling fluid) in first and second opposite directions through adjacent evaporation chambers of the plurality of evaporation chambers (as can be seen Figs. 7-9), but fails to explicitly teach in a third direction between adjacent evaporation chambers of the plurality of evaporation chambers; and the third direction is perpendicular to the first and second opposing directions. Tang teaches thermal energy management system (100; Figs. 1-2) wherein a third direction (direction of conduit 110) between adjacent evaporation chambers (evaporation chambers 106a-d) of the plurality of evaporation chambers (evaporation chambers 106a-d); and the third direction is perpendicular (as can be seen in Figs. 1-2) to the first (direction of stream 134) and second (direction of stream 132) opposing directions. It would have been obvious to a person skilled in the art before the effective filing date of the claimed invention to modify the system of Heinzl such that a third direction between adjacent absorption chambers of the plurality of absorption chambers; and the third direction is perpendicular to the first and second opposing directions as taught by Tang in order to allow a more optimum efficiency along the membrane surface (refer to par. 120 of Tang). In regards to claim 16, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 1. Further, Vandermeulen teaches wherein: the cooling liquid is water (refer to par. 7). In regards to claim 17, Heinzl as modified meets the claim limitations as disclosed above in the rejection of claim 1. Further, Vandermeulen teaches wherein: pressure in the air-gap cell is negative (refer to par. 8). Response to arguments Applicant's arguments filed on 11/10/2025 have been considered but are moot because the arguments do not apply to the newly cited references. The amended claims not taught by the previously cited references are taught by newly cited reference of Heinzl (US 20130298590). 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 MARTHA TADESSE whose telephone number is (571)272-0590. The examiner can normally be reached on 7:30am-5:00pm EST. If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Frantz Jules can be reached on 571-272-6681. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR)system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /M.T/ Examiner, Art Unit 3763 /FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
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Prosecution Timeline

Feb 13, 2024
Application Filed
Aug 21, 2025
Non-Final Rejection — §103
Nov 10, 2025
Response Filed
Feb 07, 2026
Final Rejection — §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
66%
Grant Probability
81%
With Interview (+15.1%)
3y 3m
Median Time to Grant
Moderate
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