# US 7,743,621 B2 · Multi-range composite-evaporator type cross-defrosting system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,743,621 B2 - Document ID: US7743621B2 - Status: Granted - Kind: B2 - Application number: 12/381,657 - Filed: 2009-03-16 - Published: 2009-07-09 - Granted: 2010-06-29 - Earliest claimed: 2005-12-20 - Inventors: Lung-Tan Hu - Web page: https://patentgrep.com/patent/US7743621B2 ## CPC - F25B 47/022: {hot gas defrosting} - F25B 5/02: arranged in parallel - F25B 29/003: {of the compression type system} - F25B 2400/04: Refrigeration circuit bypassing means - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract The present invention provides a multi-range composite-evaporator type cross-defrosting system for continuous heating operation under an environment temperature range from 20 degree to negative 40 degree Celsius. Said system employs a combination of two defrosting methods under different temperature and humidity conditions; the first defrosting method is used for the outdoor temperature range of 20 degree Celsius to 0 degree Celsius, the second defrosting method is used in the outdoor temperature range of 10 degree Celsius to negative 40 degree Celsius, and a control system will adjust the appropriate threshold for switching between the two defrosting methods. ## Claims ### Claim 1 A multi-range composite-evaporator type cross-defrosting system comprising: a) a refrigeration circuit comprising of four sections, which are a refrigerant-compressing section, a refrigerant-condensing section, a refrigerant-evaporating section, and a cross-defrosting section; said refrigerant-compressing section provides a flow of pressurized-refrigerant to said refrigerant-condensing section and said cross-defrosting section; said refrigerant-condensing section will condense said flow of pressurized-refrigerant therein, and release the heat energy for air-conditioning; said refrigerant-condensing section provides a flow of refrigerant to said refrigerant-evaporating section; said refrigerant-evaporating section absorbs heat from the outdoor environment and evaporates said flow of refrigerant therein, and then produces a flow of evaporated-refrigerant into said refrigerant-compressing section; b) said refrigerant-compressing section comprises at least one compressor (101); c) said refrigerant-condensing section comprises at least one main condenser (102); d) said refrigerant-evaporating section comprises at least two composite-evaporator units, which are first composite-evaporator (103) and second composite-evaporator (104); each of said composite-evaporator consists of one set of evaporation coil and one set of defrost-condensation coil; e) said cross-defrosting section comprises one refrigerant passage from said main compressor (101) to the defrost-condensation coil (105) of first composite-evaporator (103) and one refrigerant passage from said main compressor (101) to the defrost-condensation coil (106) of second composite-evaporator (104); f) flow control means for independently initiating a flow of pressurized refrigerant from said refrigerant-compressing section to the defrost-condensation coil (105) of said first composite-evaporator (103) during cross-refrigerant defrosting process of said first composite-evaporator (103); g) flow control means for independently initiating a flow of pressurized refrigerant from said refrigerant-compressing section to the defrost-condensation coil (106) of said second composite-evaporator (104) during cross-refrigerant defrosting process of said second composite-evaporator (104); h) flow control means for independently disabling the refrigerant passage from said main compressing section to the evaporation coil of first composite-evaporator (103) during the cross-air defrosting process of first composite-evaporator (103) and the cross-refrigerant defrosting process of first composite-evaporator (103); i) flow control means for independently disabling the refrigerant passage from said main compressing section to the evaporation coil of second composite-evaporator (104) during the cross-air defrosting process of second composite-evaporator (104) and the cross-refrigerant defrosting process of second composite-evaporator (104); j) a control system for commencing a defrost-cycle of cross-refrigerant defrosting process by controlling said flow control means and outdoor-air-intake means. ### Claim 2 (depends on 1) A multi-range composite-evaporator type cross-defrosting system as defined in claim 1, wherein; each composite-evaporator units includes individual heat insulation, each said outdoor-air-intake means will decrease the rate of venting during the cross-refrigerant defrosting process of its associated composite-evaporator. ### Claim 3 (depends on 1) A multi-range composite-evaporator type cross-defrosting system as defined in claim 1 further comprising: a) additional composite-evaporators, which includes one set of evaporation coil and one set of defrost-condensation coil; b) flow control means and refrigerant-passages for said additional composite-evaporators to commence the cross-refrigerant defrosting process. ### Claim 4 (depends on 3) A multi-range composite-evaporator type cross-defrosting system as defined in claim 3, wherein; when one of said composite-evaporators is defrosting with the cross-refrigerant defrosting process, this defrosting composite-evaporator will disable its associated evaporation coil and enable its associated defrost-condensation coil, and this defrost-condensation coil will generate a flow of refrigerant to the evaporation coil of other composite evaporators. ### Claim 5 (depends on 3) A multi-range composite-evaporator type cross-defrosting system as defined in claim 3; said control system will employ a continuous defrost-cycle of the cross-refrigerant defrosting process when the outdoor temperature is from 10 degree Celsius to negative 40 degree Celsius. ### Claim 6 (depends on 3) A multi-range composite-evaporator type cross-defrosting system as defined in claim 3, wherein; said control system will employ a continuous defrost-cycle of the cross-air defrosting process when the outdoor temperature is from 20 degree Celsius to 0 degree Celsius. ### Claim 7 (depends on 3) A multi-range composite-evaporator type cross-defrosting system as defined in claim 3, wherein; each of said composite-evaporators can further comprise sensor means for detecting the progress of the defrosting process; and said control system can adjust the defrost-cycle accordingly for optimum heating efficiency. ### Claim 8 A multi-range composite-evaporator type cross-defrosting system comprising: a) a refrigeration circuit comprising of four sections, which are a refrigerant-compressing section, a refrigerant-condensing section, a refrigerant-evaporating section, and a cross-defrosting section; b) said refrigerant-compressing section comprises at least one compressor (101); c) said refrigerant-condensing section comprises at least one main condenser (102); d) said refrigerant-evaporating section comprises at least two composite-evaporator units, which are first composite-evaporator (103) and second composite-evaporator (104); each of said composite-evaporator consists of one set of evaporation coil and one set of defrost-condensation coil; e) said cross-defrosting section comprises one refrigerant passage from said main compressor (101) to the defrost-condensation coil (105) of first composite-evaporator (103) and one refrigerant passage from said main compressor (101) to the defrost-condensation coil (106) of second composite-evaporator (104); f) flow control means for independently initiating a flow of pressurized refrigerant from said refrigerant-compressing section to the defrost-condensation coil (105) of said first composite-evaporator (103) during cross-refrigerant defrosting process of said first composite-evaporator (103); g) flow control means for independently initiating a flow of pressurized refrigerant from said refrigerant-compressing section to the defrost-condensation coil (106) of said second composite-evaporator (104) during cross-refrigerant defrosting process of said second composite-evaporator (104); h) flow control means for independently disabling the refrigerant passage from said main compressing section to the evaporation coil of first composite-evaporator (103) during the cross-air defrosting process of first composite-evaporator (103) and the cross-refrigerant defrosting process of first composite-evaporator (103); i) flow control means for independently disabling the refrigerant passage from said main compressing section to the evaporation coil of second composite-evaporator (104) during the cross-air defrosting process of second composite-evaporator (104) and the cross-refrigerant defrosting process of second composite-evaporator (104); j) independent air-intake means and heat insulation means for each composite-evaporator for independently heat air conservation during the associated cross-refrigerant defrosting process of each composite evaporator; k) sensor means for detecting the frost condition of each composite-evaporator, and a control system for adjusting the operation threshold for switching between the defrost-cycle of cross-air defrosting process and the defrost cycle of cross-refrigerant defrosting process, wherein: during the defrost cycle of cross-refrigerant defrosting process, at least one of said composite-evaporators will continue the refrigerant-evaporation process, thereby sustaining a continuous supply of evaporated refrigerant to said main compressor; during the defrost cycle of cross-refrigerant defrosting process, the composite-evaporator that is defrosting will enable a flow of pressurized refrigerant to the associated defrost-condenser, and the associated air-intake means will adjust the venting rate of the outdoor air to conserve the heat air inside the associated heat insulation space, thereby creating a hot environment. ### Claim 9 (depends on 8) A multi-range composite-evaporator type cross-defrosting system as defined in claim 8 further comprising: a) additional composite-evaporators; b) flow control means and refrigerant-passages for said additional composite-evaporators to commence the cross-refrigerant defrosting process, wherein: during the defrost-cycle of cross-refrigerant defrosting process, each composite-evaporator will take turns to defrost with the associated defrost-condenser; during the defrost cycle of the cross-refrigerant defrosting process, the composite-evaporator that is defrosting will enable a flow of pressurized refrigerant to the associated defrost-condenser, while all other composite-evaporators will continue the refrigerant-evaporation process to provide a continuous supply of evaporated refrigerant to the main compressor. ### Claim 10 (depends on 8) A multi-range composite-evaporator type cross-defrosting system as defined in claim 8, wherein; said control system will employ a continuous defrost-cycle of the cross-refrigerant defrosting process when the outdoor temperature is from 10 degree Celsius to negative 40 degree Celsius. ### Claim 11 A multi-range composite-evaporator type cross-defrosting system: a) a refrigeration circuit comprising of four sections, which are a refrigerant-compressing section, a refrigerant-condensing section, a refrigerant-evaporating section, and a cross-defrosting section; said refrigerant-compressing section provides a flow of pressurized-refrigerant to said refrigerant-condensing section and said cross-defrosting section; said refrigerant-condensing section will condense said flow of pressurized-refrigerant therein, and release the heat energy for air-conditioning; said refrigerant-condensing section provides a flow of refrigerant to said refrigerant-evaporating section; said refrigerant-evaporating section absorbs heat from the outdoor environment and evaporates said flow of refrigerant therein, and then produces a flow of evaporated-refrigerant into said refrigerant-compressing section; b) said refrigerant-compressing section comprises at least one compressor (101); c) said refrigerant-condensing section comprises at least one main condenser (102); d) said refrigerant-evaporating section comprises at least two composite-evaporator units, which are first composite-evaporator (103) and second composite-evaporator (104); said first composite-evaporator (103) consists of one set of evaporation coil and one set of defrost-condensation coil (105); said second composite-evaporator (104) consists of one set of evaporation coil and one set of defrost-condensation coil (106); e) said cross-defrosting section comprises one refrigerant passage from said main compressor (101) to the defrost-condensation coil (105) of the first composite-evaporator (103), and said refrigerant passage will be controlled with a first defrost-flow-valve (114) to provide a flow of pressurized refrigerant only during the cross-refrigerant defrosting process of the first composite-evaporator (103); f) said cross-defrosting section comprises one refrigerant passage from said main compressor (101) to the defrost-condensation coil (106) of the second composite-evaporator (104), and said refrigerant passage will be controlled with a second defrost-flow valve (113) to provide a flow of pressurized refrigerant only during the cross-refrigerant defrosting process of the second composite-evaporator (104); g) air-intake means and heat insulation means for conserving heat air in the first composite-evaporator (103) when the first composite-evaporator (103) is defrosting with the cross-refrigerant defrosting process; h) air-intake means and heat insulation means for conserving heat air in the second composite-evaporator (104) when the second composite-evaporator (104) is defrosting with the cross-refrigerant defrosting process; i) a first control valve (112) for independently disabling the refrigerant passage from said main compressing section to the evaporation coil of first composite-evaporator (103) when the first composite-evaporator (103) is defrosting with the cross-refrigerant defrosting process; j) a second control valve (111) for independently disabling the refrigerant passage from said main compressing section to the evaporation coil of second composite-evaporator (104) when the second composite-evaporator (104) is defrosting with the cross-refrigerant defrosting process; k) sensor means for detecting the frost condition of each composite-evaporator; l) a control system for commencing the full capacity heating operation and the defrost-cycle of the cross-refrigerant defrosting process by controlling said control valves and air-intake means, wherein: said control system will adjust each process duration of said defrost-cycle of the cross-refrigerant defrosting process according to the frost condition of each composite-evaporator; during the defrost cycle of the cross-refrigerant defrosting process, at least one of said composite-evaporators will continue the refrigerant-evaporation process, thereby sustaining a continuous supply of evaporated refrigerant to said main compressor (101); during the defrost cycle of the cross-refrigerant defrosting process, the composite-evaporator that is defrosting will enable a flow of pressurized refrigerant to the associated defrost-condenser, and the associated air-intake means will adjust the venting rate of the outdoor air to conserve the heat air inside the associated heat insulation space, thereby creating a hot environment; during the defrost cycle of the cross-refrigerant defrosting process, the defrost-condenser associated with the composite-evaporator that is defrosting will receive a flow of pressurized refrigerant from said main compressor (101), said flow of pressurized refrigerant will condense and be circulated to the other composite-evaporator of said refrigerant-evaporating section via pressure regulating means. ### Claim 12 (depends on 11) A multi-range composite-evaporator type cross-defrosting system as defined in claim 11 further comprising: a) additional composite-evaporators; b) flow control means and refrigerant-passages for said additional composite-evaporators to commence the cross-refrigerant defrosting process, wherein: during the defrost-cycle of cross-refrigerant defrosting process, each composite-evaporator will take turns to defrost with the associated defrost-condenser; during the defrost cycle of the cross-refrigerant defrosting process, the composite-evaporator that is defrosting will enable a flow of pressurized refrigerant to the associated defrost-condenser, while all other composite-evaporators will continue the refrigerant-evaporation process to provide a continuous supply of evaporated refrigerant to the main compressor. ### Claim 13 (depends on 11) A multi-range composite-evaporator type cross-defrosting system as defined in claim 11, wherein; said first defrost-flow valve (114) and second defrost-flow valve (113) are constructed as one multi-port control valve. ### Claim 14 (depends on 11) A multi-range composite-evaporator type cross-defrosting system as defined in claim 11, wherein; said first control valve (112) and second control valve (111) are constructed as one multi-port control valve.