# US 2014/0360216 A1 · Gas defrosting system for refrigeration units using fluid cooled condensers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360216 A1 - Document ID: US20140360216A1 - Status: Published application - Kind: A1 - Application number: 13/910,878 - Filed: 2013-06-05 - Published: 2014-12-11 - Earliest claimed: 2013-06-05 - Assignees: Hill Phoenix, Inc. - Applicants: Hill Phoenix, Inc. - Inventors: James Boyko - Web page: https://patentgrep.com/patent/US20140360216A1 ## CPC - F25D 21/06: Removing frost (defrosting cycles F25B47/02) - F25B 47/02: Defrosting cycles - F25D 21/12: by hot-fluid circulating system separate from the refrigerant system - F25B 2339/047: Water-cooled condensers - F25D: REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR (refrigerated showcases A47F3/04; thermally-insulated vessels for domestic use A47J41/00; refrigerated vehicles, see the appropriate subclasses of classes B60 - B64; containers with thermal insulation in general B65D81/38; heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants, or materials for the production of heat or cold by chemical reactions other than by combustion C09K5/00; thermally-insulated vessels for liquefied or solidified gases F17C; air-conditioning or air-humidification F24F; refrigeration machines, plants, or systems F25B; cooling of instruments or comparable apparatus without refrigeration G12B) - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract A gas defrosting system is disclosed for efficiently defrosting refrigeration units using fluid-cooled condensers. For each refrigeration unit in refrigeration mode, a cool condenser fluid is applied to the condenser to achieve a high thermodynamic efficiency. For each refrigeration unit in defrost mode, a warm defrost fluid is applied to the condenser to expedite the defrost process. ## Claims ### Claim 1 A system for defrosting refrigeration units, the system comprising: single or multiple refrigeration units, each of said refrigeration units comprising a condenser, an evaporator, and an expansion valve, wherein each of said refrigeration units is operable in: a refrigeration mode during which said refrigeration units are applied for providing useful cooling, and a defrost mode during which a gas defrost method is applied for removing frost from said evaporator; a means for transferring a condenser fluid through said condenser during said refrigeration mode; and a means for transferring a defrost fluid through said condenser during said defrost mode. ### Claim 2 (depends on 1) The system for defrosting refrigeration units of claim 1, wherein a temperature of said defrost fluid equals or exceeds 80 degrees F. ### Claim 3 (depends on 1) The system for defrosting refrigeration units of claim 1, wherein said condenser fluid and said defrost fluid have an identical chemical composition. ### Claim 4 (depends on 1) The system for defrosting refrigeration units of claim 1, further comprising: a heat exchanger installed between said evaporator and said compressor; and a means for transferring said defrost fluid to said heat exchanger during said defrost mode. ### Claim 5 (depends on 1) The system for defrosting refrigeration units of claim 1, wherein said expansion valve is configured to sense an amount of superheat of a fluid refrigerant circulated by said refrigeration units using a sensor positioned between said heat exchanger and said compressor. ### Claim 6 (depends on 1) The system for defrosting refrigeration units of claim 1, wherein a temperature of said defrost fluid is maintained by a heating means having a higher efficiency relative to electric resistance heating. ### Claim 7 A refrigeration system comprising: a refrigeration circuit comprising a condenser, an evaporator, and a compressor configured to circulate a fluid refrigerant through the condenser and the evaporator; a condenser fluid circuit separate from the refrigeration circuit and configured to circulate a chilled condenser fluid through the condenser to provide cooling for the fluid refrigerant in the condenser when the refrigeration system is operated in a refrigeration mode; a defrost fluid circuit separate from the refrigeration circuit and configured to circulate a heated defrost fluid through the condenser to provide heating for the fluid refrigerant in the condenser when the refrigeration system is operated in a defrost mode; and one or more valves configured to switch between circulating the chilled condenser fluid through the condenser in the refrigeration mode and circulating the heated defrost fluid through the condenser in the defrost mode. ### Claim 8 (depends on 7) The refrigeration system of claim 7, the one or more valves comprising: a condenser inlet valve having a first inlet port fluidly connected to a supply line for the chilled condenser fluid, a second inlet port fluidly connected to a supply line for the heated defrost fluid, and an outlet port fluidly connected to an inlet of the condenser; and a condenser outlet valve having an inlet port fluidly connected to an outlet of the condenser, a first outlet port fluidly connected to return line for the chilled condenser fluid, and a second outlet port fluidly connected to a return line for the heated defrost fluid ### Claim 9 (depends on 8) The refrigeration system of claim 8, wherein the condenser fluid circuit and the defrost fluid circuit have a shared flow path between the condenser inlet valve and the condenser outlet valve; wherein the condenser is disposed along the shared flow path between the condenser inlet valve and the condenser outlet valve. ### Claim 10 (depends on 7) The refrigeration system of claim 7, further comprising: a heat exchanger disposed in series between the evaporator and the compressor of the refrigeration circuit and fluidly connected to the defrost fluid circuit; wherein the heat exchanger is configured to heat the fluid refrigerant between the evaporator and the compressor using heat from the heated defrost fluid when the refrigeration system is operated in the defrost mode. ### Claim 11 (depends on 7) The refrigeration system of claim 7, the condenser fluid circuit comprising: a cooling unit configured to provide cooling for the chilled condenser fluid; and a condenser fluid pump configured to circulate the chilled condenser fluid between the cooling unit and the condenser. ### Claim 12 (depends on 7) The refrigeration system of claim 7, the defrost fluid circuit comprising: a defrost fluid heater configured to provide heating for the heated defrost fluid; and a defrost fluid pump configured to circulate the heated defrost fluid between the defrost fluid heater and the condenser. ### Claim 13 (depends on 12) The refrigeration system of claim 12, wherein the defrost fluid heater is configured to maintain the heated defrost fluid at a gas defrost temperature while the refrigeration system is operated in the refrigeration mode; wherein the gas defrost temperature is higher than a temperature of the chilled condenser fluid. ### Claim 14 A method for defrosting a refrigeration unit, the method comprising: circulating a fluid refrigerant through a refrigeration circuit between an evaporator and a condenser; operating the refrigeration unit in a refrigeration mode during which a chilled condenser fluid is circulated through a condenser fluid circuit separate from the refrigeration circuit to provide cooling for the fluid refrigerant in the condenser; operating the refrigeration unit in a defrost mode during which a heated defrost fluid is circulated through a defrost fluid circuit separate from the refrigeration circuit to provide heating for the fluid refrigerant in the condenser; and controlling one or more valves to switch between circulating the chilled condenser fluid through the condenser in the refrigeration mode and circulating the heated defrost fluid through the condenser in the defrost mode. ### Claim 15 (depends on 14) The method of claim 14, wherein controlling the one or more valves comprises: controlling a condenser inlet valve having a first inlet port fluidly connected to a supply line for the chilled condenser fluid, a second inlet port fluidly connected to a supply line for the heated defrost fluid, and an outlet port fluidly connected to an inlet of the condenser; and controlling a condenser outlet valve having an inlet port fluidly connected to an outlet of the condenser, a first outlet port fluidly connected to return line for the chilled condenser fluid, and a second outlet port fluidly connected to a return line for the heated defrost fluid. ### Claim 16 (depends on 15) The method of claim 15, wherein controlling the one or more valves comprises: routing the chilled condenser fluid along a flow path between the condenser inlet valve and the condenser outlet valve during the refrigeration mode; and routing the heated defrost fluid along the flow path between the condenser inlet valve and the condenser outlet valve during the defrost mode; wherein the flow path between the condenser inlet valve and the condenser outlet valve is shared by the condenser fluid circuit and the defrost fluid circuit, and wherein the condenser is disposed along the shared flow path. ### Claim 17 (depends on 14) The method of claim 14, wherein operating the refrigeration unit in the defrost mode comprises: circulating the heated defrost fluid through a heat exchanger disposed in series between the evaporator and the compressor of the refrigeration circuit; and heating the fluid refrigerant in the heat exchanger between the evaporator and the compressor using heat from the heated defrost fluid. ### Claim 18 (depends on 14) The method of claim 14, wherein operating the refrigeration unit in the refrigeration mode comprises: circulating the chilled condenser fluid through a cooling unit of the condenser fluid circuit to provide cooling for the chilled condenser fluid; and operating a condenser fluid pump to circulate the chilled condenser fluid between the cooling unit and the condenser. ### Claim 19 (depends on 14) The method of claim 14, wherein operating the refrigeration unit in the defrost mode comprises: circulating the heated defrost fluid through a defrost fluid heater of the defrost fluid circuit to provide heating for the heated defrost fluid; and operating a defrost fluid pump to circulate the heated defrost fluid between the defrost fluid heater and the condenser. ### Claim 20 (depends on 14) The method of claim 14, further comprising: using a defrost fluid heater of the defrost fluid circuit to maintain the heated defrost fluid at a gas defrost temperature while the refrigeration system is operated in the refrigeration mode; wherein the gas defrost temperature is higher than a temperature of the chilled condenser fluid.