# US 7,610,766 B2 · High-speed defrost refrigeration system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,610,766 B2 - Document ID: US7610766B2 - Status: Granted - Kind: B2 - Application number: 11/056,117 - Filed: 2005-02-14 - Published: 2005-06-30 - Granted: 2009-11-03 - Earliest claimed: 2002-07-08 - Inventors: Serge Dubé - Web page: https://patentgrep.com/patent/US7610766B2 ## CPC - F25B 5/02: arranged in parallel - F25B 41/00: Fluid-circulation arrangements - F25B 47/022: {hot gas defrosting} - F25B 43/006: {Accumulators} - F25B 2341/0015: using two or more ejectors - F25B 2400/075: with parallel compressors - F25B 2400/16: Receivers - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract A defrost refrigeration system of the type having a main refrigeration circuit operating a refrigeration cycle. The defrost refrigeration system comprises a first line extending from the first compressor to the evaporator stage and is adapted to receive a portion of discharged low-pressure refrigerant from the first compressor. Valves are provided for stopping a suction of cooling refrigerant in an evaporator of the evaporator stage and for directing a flow of defrost refrigerant to release heat to defrost the evaporator. A second line is provided for directing the refrigerant having released heat to the expansion stage of the refrigeration cycle. A pressure reducing device is optionally positioned downstream of the condensing stage for adjusting a pressure of the refrigerant in the high-pressure liquid state mixing with the defrost refrigerant having released heat. ## Claims ### Claim 1 A defrost refrigeration system of the type having a main refrigeration circuit operating a refrigeration cycle, wherein a refrigerant goes through at least a compressing stage having at least a first and a second compressor, wherein said refrigerant is compressed to a high-pressure gas state to then reach a condensing stage, wherein said refrigerant in said high-pressure gas state is condensed at least partially to a high-pressure liquid state to then reach an expansion stage, wherein said refrigerant in said high-pressure liquid state is expanded to a first low-pressure liquid state to then reach an evaporator stage, wherein said refrigerant in said first low-pressure liquid state is evaporated, at least partially to a first low-pressure gas state by absorbing heat, to then return to said compressing stage, said defrost refrigeration system comprising a first line extending from said first compressor to the evaporator stage and adapted to receive all of the discharged refrigerant from said first compressor, a valve for stopping a suction by the compressing stage of said refrigerant in said first low-pressure liquid state in at least one evaporator of the evaporator stage and directing a flow of said discharged refrigerant to release heat to defrost the at least one evaporator and thereby changing phase at least partially to a second low-pressure liquid state, a second line for directing all of said refrigerant having released heat to the expansion stage of the refrigeration cycle, and a pressure reducing device downstream of the condensing stage for adjusting a pressure of the refrigerant in the high-pressure liquid state mixing with said refrigerant having released heat. ### Claim 2 (depends on 1) The defrost refrigeration system according to claim 1, further comprising a pressure reducing device in the first line so as to reduce a pressure of the discharged low-pressure refrigerant prior to defrosting the at least one evaporator. ### Claim 3 (depends on 1) The defrost refrigeration system according to claim 1, wherein all of the refrigerant in the high-pressure gas state discharged by the second compressor is directed to the condensing stage. ### Claim 4 (depends on 1) The defrost refrigeration system in accordance with claim 1, further comprising a sub-cooling system liquefying a mixture of the cooling refrigerant and the defrost refrigerant. ### Claim 5 (depends on 1) The defrost refrigeration system in accordance with claim 1, further comprising a sub-cooling system liquefying the cooling refrigerant prior to being mixed with the defrost refrigerant. ### Claim 6 A method for defrosting evaporators in a refrigeration system of the type having a cooling refrigerant circulating sequentially between a compression stage, a condensing stage, an expansion stage and an evaporation stage to then return to the compression stage, comprising: i) stopping a suction of the cooling refrigerant in a first evaporator of the evaporation stage; ii) directing defrost refrigerant from the compression stage to the first evaporator so as to defrost the first evaporator; iii) directing the defrost refrigerant from the first evaporator upstream of the expansion stage; and iv) mixing the cooling refrigerant exiting from the condensing stage with the defrost refrigerant by controlling a cooling refrigerant pressure downstream of the condensing stage; and v) exposing the mixture of cooling refrigerant and defrost refrigerant to a heat exchanger to remove excess gas from the mixture; vi) directing all of the mixture to the expansion stage; whereby a second evaporator of the evaporation stage is cooled with the mixture of cooling refrigerant from the condensing stage with the defrost refrigerant. ### Claim 7 (depends on 6) The method according to claim 6, wherein the defrost refrigerant in step ii) is compressed to a reduced pressure by a dedicated compressor. ### Claim 8 (depends on 6) The method according to claim 6, wherein step ii) comprises converting a portion of the cooling refrigerant into the defrost refrigerant by reducing a pressure of the portion of the cooling refrigerant exiting the compression stage. ### Claim 9 (depends on 6) The method according to claim 6, further comprising a step of liquefying the cooling refrigerant prior to step iv). ### Claim 10 A method for installing a defrost system in a refrigeration system of the type having a cooling refrigerant circulating sequentially during a refrigeration cycle between a compression stage, a condensing stage, an expansion stage and an evaporation stage to then return to the compression stage, comprising: providing a valve to stop a suction of cooling refrigerant in at least a first evaporator of the evaporation stage; positioning a first line feeding the first evaporator with defrost refrigerant from the compression stage in a defrost cycle; positioning a second line between the first evaporator and a main line between the condensing stage and the expansion stage to direct the defrost refrigerant from the first evaporator to the main line to feed at least a second evaporator in the refrigeration cycle; providing a pressure reducing device in the main line to reduce the pressure of the cooling refrigerant for a subsequent mixing with the defrost refrigerant from the second line in the refrigeration cycle; and providing a sub-cooling system f or liquefying all of the mixture of cooling refrigerant and defrost refrigerant. ### Claim 11 (depends on 10) The method according to claim 10, further comprising a step of providing a pressure reducing configuration so as to convert the cooling refrigerant fed to the first evaporator into a defrost refrigerant of a given reduced pressure. ### Claim 12 (depends on 11) The method according to claim 11, wherein the pressure reducing configuration has a pressure regulator in the first line. ### Claim 13 (depends on 11) The method according to claim 11, wherein the pressure reducing configuration has a compressor directly connected to the first line such that an output of the compressor is below an output of other compressors of the compression stage. ### Claim 14 (depends on 10) The method according to claim 10, further comprising a step of providing a sub-cooling system for liquefying the cooling refrigerant prior to mixing the cooling refrigerant with the defrost refrigerant in the main line.