Patents by Inventor Richard N. Christensen
Richard N. Christensen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11708914Abstract: Valves may include an opening sized and shaped to permit a subject fluid to flow through the opening when the opening is unobstructed. A heat exchange element may be located proximate to the opening, the heat exchange element positioned and configured to induce a localized phase change in the subject fluid to form and unform a solid plug from the subject fluid around at least a portion of the heat exchange element. A heat transfer rate of the heat exchange element may be variable to control a rate of flow of the subject fluid through the valve by controlling a size of the solid plug from the subject fluid.Type: GrantFiled: November 8, 2021Date of Patent: July 25, 2023Assignees: Battelle Energy Alliance, LLC, University of IdahoInventors: Piyush Sabharwall, Richard N. Christensen, Paul Marotta
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Publication number: 20220163130Abstract: Valves may include an opening sized and shaped to permit a subject fluid to flow through the opening when the opening is unobstructed. A heat exchange element may be located proximate to the opening, the heat exchange element positioned and configured to induce a localized phase change in the subject fluid to form and unform a solid plug from the subject fluid around at least a portion of the heat exchange element. A heat transfer rate of the heat exchange element may be variable to control a rate of flow of the subject fluid through the valve by controlling a size of the solid plug from the subject fluid.Type: ApplicationFiled: November 8, 2021Publication date: May 26, 2022Inventors: Piyush Sabharwall, Richard N. Christensen, Paul Marotta
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Patent number: 7062913Abstract: A heat engine (10) achieves operational efficiencies by: 1) recovering waste heat from heat engine expander (14) to preheat heat-engine working fluid, 2) using super-heated working fluid from compressor (402) to pre-heat heat-engine working fluid, and 3) using reject heat from condenser (93) and absorber (95) to heat the heat-engine boiler (12). A dual heat-exchange generator (72) affords continuous operation by using gas-fired heat exchanger (212) to heat generator (72) when intermittent heat source (40), e.g., solar, is incapable of heating generator (72). The combination of heat engine (10) and absorption and compression heat transfer devices (60, 410) allows use of low-temperature heat sources such as solar, bio-mass, and waste heat to provide refrigeration, heating, work output including pumping and heating of subterranean water and electrical generation.Type: GrantFiled: December 15, 2000Date of Patent: June 20, 2006Assignee: The Ohio State UniversityInventors: Richard N. Christensen, Jiming Cao, E. Thomas Henkel
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Publication number: 20030000213Abstract: A heat engine (10) achieves operational efficiencies by: 1) recovering waste heat from heat engine expander (14) to preheat heat-engine working fluid, 2) using super-heated working fluid from compressor (402) to pre-heat heat-engine working fluid, and 3) using reject heat from condenser (93) and absorber (95) to heat the heat-engine boiler (12). A dual heat-exchange generator (72) affords continuous operation by using gas-fired heat exchanger (212) to heat generator (72) when intermittent heat source (40), e.g., solar, is incapable of heating generator (72). The combination of heat engine (10) and absorption and compression heat transfer devices (60, 410) allows use of low-temperature heat sources such as solar, bio-mass, and waste heat to provide refrigeration, heating, work output including pumping and heating of subterranean water and electrical generation.Type: ApplicationFiled: June 15, 2002Publication date: January 2, 2003Inventors: Richard N. Christensen, Jiming Cao, E. Thomas Henkel
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Patent number: 6314752Abstract: A mass and heat transfer device uses a substantially vertical surface to separating a first fluid space from a second fluid space with the first fluid space containing a downward flowing liquid in at least a partially flooded state and an upward flowing gas contained at least partially within the downward flowing liquid. A fluid distribution surface with one or more apertures is provided within the first fluid space with the apertures controlling the downward passage and distribution of the downward flowing liquid and the upward passage and distribution of the upward flowing gas. A heat transfer fluid is used in the second fluid space for heat transfer with fluids in the first fluid space. The fluid distribution surface can be used in a horizontal, vertical or angled position and in annular, cylindrical, and hexahedral forms.Type: GrantFiled: December 17, 1999Date of Patent: November 13, 2001Assignee: The Ohio State University Research FoundationInventors: Richard N. Christensen, Michael A. Garrabrant, Roger F. Stout
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Patent number: 5704417Abstract: A fluid heat exchange apparatus is disclosed that can be used as an absorber in an absorption cooling system. The compact absorber design uses an accordion fin assembly to direct solution downward through the absorber on a plurality of alternatively angled fins. The alternatively angled fins cause the solution to collect at each level against a thermally conductive surface. Each fin includes a plurality of house-shaped perforations that allow the solution to spill over onto the next level fin. The house-shaped perforations also allow the vapor to flow upward in effective counterflow with the solution.Type: GrantFiled: August 23, 1996Date of Patent: January 6, 1998Assignee: Gas Research InstituteInventors: Richard N. Christensen, Srinivas Garimella, Yong Tae Kang, Michael Garrabrant
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Patent number: 5636527Abstract: Apparatus for mass transfer of gas and liquid flowing through passages therein has a vertical enclosure formed in a pair of sheet metal plates sealed together around their periphery and formed to have rows of horizontal passages communicating with columns of vertical passages in and adjacent to a vertical plane defined by flat contiguous areas of the plates between and around the passages. The inner surfaces of the passages have highly wettable areas to substantially maximize transfer of mass and heat. Each horizontal passage is continuous between the vertical passages with which it communicates.Type: GrantFiled: November 15, 1995Date of Patent: June 10, 1997Assignee: The Ohio State University Research FoundationInventors: Richard N. Christensen, Stephen E. Petty
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Patent number: 5617737Abstract: A capillary twisted fluted tube is formed with an interior helical capillary flute and associated interior helical crest and a complementary exterior helical crest and flute, respectively. Liquid rises in the interior capillary flute and is expelled at or near the top of the tube in fine droplets that promote mass transfer efficiencies as a result of improved vapor-equilibrium. A capillary fluted tube placed in a helical groove of a heat insulating material to expose only one side of the tube to hot combustion products promotes increased capillary rise on one side of the tube with increased expulsion and spatter of liquid from the capillary channel. Exterior tube heat transfer is enhanced by enclosing the tube in a second tube or forming the tube into a winding and enclosing the winding in a cylinder. Contact of the exterior tube crests with the enclosing tube or cylinder improves heat transfer efficiencies as a result of confined flow of heat transfer fluid within the enclosing tube or cylinder.Type: GrantFiled: August 2, 1995Date of Patent: April 8, 1997Assignee: The Ohio State University Research FoundationInventors: Richard N. Christensen, F. Bert Cook, Yong-Tae Kang
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Patent number: 5572884Abstract: An absorption refrigeration machine with two, non-fluid linked loops uses heat from a first loop rectifier to heat a second loop generator by either direct or hydronic heat exchange. Flue gas from the heating of the first loop generator is used to heat strong solution in the second loop. Heat from the first loop condenser and absorber are also used to heat the second loop generator by either direct or hydronic fluid coupling. In order to improve further the efficiencies of the absorption machine, a mass and heat transfer device is used that provides a liquid and vapor distribution system that affords effective heat transfer in conjunction with a large and continually renewed liquid surface area and a relatively constant vapor velocity to effect efficient mass transfer among the various components and processes of the refrigeration machine. A simple liquid metering system is used to meter equal amounts of liquid into the divided liquid flow arrangements used in various components of the machine.Type: GrantFiled: November 4, 1994Date of Patent: November 12, 1996Assignee: The Ohio State University Research FoundationInventors: Richard N. Christensen, Srinivas Garimella
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Patent number: 5546760Abstract: An absorption refrigeration and heating system has helical concentric coils for two generators (80 and 81) and recuperators (86 and 95) on a common axis (232) with a heating unit (84) at the center and allowing the hot combustion gases (245) to circulate in serpentine fashion through separate concentric chambers containing the coils.An absorber (97), condenser (100) and recuperator (107) are placed in a single module (270) and configured with a tube-in-tube or tube-in-cylinder construction with fluted inner tubes. A general purpose, divided-flow, tube-in-cylinder, heat-transfer device (400) is used to reduce the pressure drop in the circulating fluid.Type: GrantFiled: June 7, 1995Date of Patent: August 20, 1996Assignee: Columbia Gas of Ohio, Inc.Inventors: F. Bert Cook, Stephen E. Petty, Howard C. Meacham, Jr., Richard N. Christensen, Kevin R. McGahey
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Patent number: 5533362Abstract: A refrigeration and heating system in which an absorber (97), condenser (100) and recuperator are placed (107) in a single module (270) and are provided with tube-in-tube or tube-in-cylinder construction with fluted inner tubes. A general purpose, divided-flow, tube-in-cylinder, heat transfer device (400) is used to reduce the pressure drop in the circulating fluid.Type: GrantFiled: August 19, 1994Date of Patent: July 9, 1996Assignee: Columbia Gas of Ohio, Inc.Inventors: F. Bert Cook, Stephen E. Petty, Howard C. Meacham, Jr., Richard N. Christensen, Kevin R. McGahey
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Patent number: 5339654Abstract: A refrigeration and heating system has been made in which improved efficiencies are obtained by placing helical concentric coils of at least two generators (80 and 81) and recuperators (86 and 95) on a common axis (232) with a heating unit (84) at the center and allowing the hot combustion gases (245) to circulate in serpentine fashion through separate concentric chambers containing the coils. Further efficiencies are obtained by placing an absorber (97), condenser (100) and recuperator (107) in a single module (270) and by using tube-in-tube or tube-in-cylinder construction with fluted inner tubes. A general purpose, divided-flow, tube-in-cylinder, heat-transfer device (400) is used to reduce the pressure drop in the circulating fluid.Type: GrantFiled: October 9, 1991Date of Patent: August 23, 1994Assignee: Columbia Gas System Service CorporationInventors: F. Bert Cook, Stephen E. Petty, Howard C. Meacham, Jr., Richard N. Christensen, Kevin R. McGahey
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Patent number: 5097819Abstract: A direct contact condensing heat-exchanger is provided with a water heat transfer medium in which combustion product gases are dispersed in finely divided bubble form against a relatively low hydrostatic pressure differential for efficient sensible heat and latent heat recovery purposes. In one actual application, a warm-air furnace system having a burner that produces combustion product gases as a heat source is provided with the novel direct contact condensing heat-exchanger as a seondary heat-exchanger that advantageously recovers both sensible heat and latent heat from the combustion product gases.Type: GrantFiled: June 24, 1991Date of Patent: March 24, 1992Assignee: Gas Research InstituteInventors: Sherwood G. Talbert, Anthony C. DeVuono, Richard N. Christensen, Paul E. George, II
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Patent number: 5067330Abstract: A refrigeration and heating system has been made in which improved efficiencies are obtained by placing helical concentric coils of at least two generators and recuperators on a common axis with a heating unit at the center and allowing the hot combustion gases to circulate in serpentine fashion through separate concentric chambers containing the coils. Further efficiencies are obtained by placing an absorber, condenser and recuperator with a single module and by using tube-in-tube or tube-in-cylinder construction with fluted inner tubes.Type: GrantFiled: February 9, 1990Date of Patent: November 26, 1991Assignee: Columbia Gas System Service CorporationInventors: F. Bert Cook, Stephen E. Petty, Howard C. Meacham, Jr., Richard N. Christensen, Kevin R. McGahey
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Patent number: 4926659Abstract: A absorption refrigeration system having cooling and heating modes of operation functions with a double-effect or "split" refrigeration cycle having approximately the same refrigerant concentration span in each cycle loop. The system includes a novel direct expansion combined evaporator and absorber assembly with improved heat transfer characteristics and with interchangeable liquid flows accomplished through actuation of a conventional reversing valve. Also, the system is provided with improved recuperative heat exchangers to further increase system energy conversion efficiencies.Type: GrantFiled: March 30, 1989Date of Patent: May 22, 1990Assignee: Gas Research InstituteInventors: Richard N. Christensen, Anthony C. DeVuono, William H. Wilkinson, D. Karl Landstrom