# US 11,306,951 B2 · Refrigeration system with separate feedstreams to multiple evaporator zones > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,951 B2 - Document ID: US11306951B2 - Status: Granted - Kind: B2 - Application number: 15/710,566 - Filed: 2017-09-20 - Published: 2018-01-11 - Granted: 2022-04-19 - Earliest claimed: 2014-02-07 - Assignees: PDX Technologies LLC - Applicants: PDX Technologies LLC - Inventors: John Scherer - Web page: https://patentgrep.com/patent/US11306951B2 ## CPC - F25B 31/004: {oil recirculating arrangements} - F25B 5/02: arranged in parallel - F25B 5/04: arranged in series - F25B 13/00: Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) - F25B 39/028: {having distributing means} - F25B 40/06: Superheaters - F25B 41/22: between evaporator and compressor - F25B 41/385: Dispositions with two or more expansion means arranged in parallel on a refrigerant line leading to the same evaporator - F25B 49/02: for compression type machines, plants or systems - F28D 1/0417: {with particular circuits for the same heat exchange medium, e.g. with the heat exchange medium flowing through sections having different heat exchange capacities or for heating/cooling the heat exchange medium at different temperatures} - F28D 1/0477: {the conduits being bent in a serpentine or zig-zag} - F28F 9/0275: {with multiple branch pipes} - F28F 27/02: for controlling the distribution of heat-exchange media between different channels ({static flow control means in header boxes F28F9/026}; arrangements of guide plates or guide vanes F28F9/22, F28F25/12) - F25B 2339/02: Details of evaporators - F25B 2339/04: Details of condensers - F25B 2341/0683: the sensor is disposed in the suction line and influenced by the temperature or the pressure of the suction gas - F25B 2400/01: Heaters - F25B 2600/2513: Expansion valves - F25B 2700/197: of the evaporator - F25B 2700/2117: of an evaporator - F28D 2021/0071: {Evaporators} - F28F 2250/06: Derivation channels, e.g. bypass - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general) - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) ## Abstract A refrigeration system has: (a) a fluid tight circulation loop including a compressor, a condenser and an evaporator, the evaporator having at least three evaporator zones, each evaporator zone having an inlet port, the circulation loop being further configured to measure the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port; and control the flow of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator, and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator upstream of the evaporator outlet port. ## Claims ### Claim 1 A method of controlling a refrigeration system, wherein the refrigeration system comprises a refrigerant disposed within a fluid-tight circulation loop comprising a continuous length of tubing, the refrigeration system including a compressor, a condenser and an evaporator, the refrigerant being capable of existing in a liquefied state, a gaseous state and a two-phase state comprising both refrigerant in the liquefied state and refrigerant in the gaseous state, the evaporator having an outlet port and at least three evaporator zones in series provided by the continuous length of tubing, each evaporator zone having (i) an evaporator zone inlet port and (ii) an evaporator feed input control valve upstream of the inlet port, the method comprising the steps of: (a) compressing refrigerant in a gaseous state within the compressor and cooling the refrigerant within the condenser to yield refrigerant in the liquefied state; (b) flowing refrigerant from the condenser into the evaporator via the inlet port and the control valve of each evaporator zone, wherein the refrigerant partially exists in a two-phase state, and wherein refrigerant introduced into each evaporator zone through its inlet port and evaporator feed input control valve flows directly into the next evaporator zone in series until the refrigerant exits the evaporator through the outlet port in step (c); and (c) flowing refrigerant from the evaporator to the compressor. ### Claim 2 (depends on 1) The method of claim 1 wherein the continuous length of tubing continually and smoothly expands from the inlet port of the most upstream evaporator zone to the outlet port of the evaporator. ### Claim 3 (depends on 1) The method of claim 1 further comprising the step (d) of measuring the condition of the refrigerant with a plurality of refrigerant condition sensors. ### Claim 4 (depends on 3) The method of claim 3 wherein step (d) comprises measuring the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the outlet port. ### Claim 5 (depends on 4) The method of claim 4, further comprising the step of controlling with a controller the flow rate of refrigerant to the evaporator in step (b) based upon the measured condition of the refrigerant condition of the refrigerant from step (d), wherein the controlling of the refrigerant flow rate to the evaporator is carried out by controlling the refrigerant flow rate to each of the evaporator zones with separate signals from the controller. ### Claim 6 (depends on 4) The method of claim 4, wherein the measuring of the refrigerant condition is carried out with a refrigerant condition sensor disposed within each of the evaporator zones. ### Claim 7 (depends on 1) The method of claim 1 wherein the flowing of refrigerant from the condenser into the evaporator in step (b) is carried out after cooling the refrigerant in a precooler disposed downstream of the condenser and upstream of the evaporator. ### Claim 8 (depends on 1) The method of claim 1 wherein the flowing of refrigerant from the condenser into the evaporator in step (b) is carried out after cooling the refrigerant by thermal contact with evaporating refrigerant in a precooler disposed downstream of the condenser and upstream of the evaporator thermal contact with evaporating refrigerant. ### Claim 9 (depends on 1) The method of claim 1 comprising the additional step of flowing a portion of the refrigerant exiting the evaporator to the inlet port of each of the evaporator zones. ### Claim 10 (depends on 1) The method of claim 1 comprising the additional step of flowing a portion of the refrigerant exiting the evaporator to the inlet port of each of the evaporator zones via a vapor booster operated to maintain two phase refrigerant volume in the evaporator at equilibrium with evaporator respective internal volume under all loading conditions. ### Claim 11 (depends on 1) The method of claim 1 wherein the condenser has a plurality of condenser zones, each condenser zone having a condenser zone inlet port. ### Claim 12 A refrigeration system comprising: (a) a fluid tight circulation loop comprising a continuous length of tubing, the fluid tight circulation loop including a compressor, a condenser and an evaporator, the circulating loop being configured to continuously circulate a refrigerant which is capable of existing in a liquefied state, a gaseous state and a two-phase state comprising both refrigerant in the liquefied state and refrigerant in the gaseous state, the evaporator having an outlet port and at least three evaporator zones in series provided by the continuous length of tubing, each evaporator zone having (i) an inlet port and (ii) an evaporator feed input control valve upstream of the inlet port, the circulation loop being further configured to (i) compress refrigerant in a gaseous state within the compressor and cool the refrigerant within the condenser to yield refrigerant in the liquefied state; (ii) flow refrigerant from the condenser into the evaporator via the inlet port and the control valve of each evaporator zone, wherein the refrigerant partially exists in a two-phase state, and wherein refrigerant introduced into each evaporator zone through its inlet port and evaporator feed input control valve flows directly into the next evaporator zone in series until the refrigerant exits the evaporator through the outlet port; and (iii) flow refrigerant from the evaporator to the compressor; and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon a measured condition of the refrigerant received from a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port. ### Claim 13 (depends on 12) The refrigeration system of claim 12 wherein the continuous length of tubing continually and smoothly expands from the inlet port of the most upstream evaporator zone to the outlet port of the evaporator. ### Claim 14 (depends on 12) The refrigeration system of claim 12 wherein the measured condition of the refrigerant is measured by—a plurality of refrigerant condition sensors. ### Claim 15 (depends on 12) The refrigeration system of claim 12 wherein the measuring of the refrigerant condition in the function described in (b) is carried out with a refrigerant condition sensor disposed within each of the evaporator zones. ### Claim 16 (depends on 15) The refrigeration system of claim 15 wherein the controlling of the refrigerant flow rate to the evaporator in the function described in (b) is carried out by controlling the refrigerant flow rate to each of the evaporator zones with separate signals from the controller. ### Claim 17 (depends on 12) The refrigeration system of claim 12 further comprising a precooler disposed downstream of the condenser and upstream of the evaporator, and wherein the flowing of refrigerant from the condenser into the evaporator in the function described in (a)(ii) is carried out after cooling the refrigerant in the precooler. ### Claim 18 (depends on 12) The refrigeration system of claim 12 further comprising recycling conduits for flowing a portion of the refrigerant exiting the evaporator to the inlet port of each of the evaporator zones. ### Claim 19 (depends on 18) The refrigeration system of claim 18 comprising a vapor pressure booster capable of maintaining two phase refrigerant in the evaporator at equilibrium under all loading conditions. ### Claim 20 (depends on 12) The refrigeration system of claim 12 wherein the condenser has a plurality of condenser zones, each condenser zone having a condenser zone inlet port. ### Claim 21 (depends on 12) The refrigeration system of claim 12 further comprising reversing conduits and valves for alternatively (i) flowing refrigerant from a discharge side of the compressor to the evaporator inlet ports without first flowing to the condenser, (ii) flowing refrigerant exiting the evaporator to the outlet port of the condenser, (iii) flowing refrigerant from the outlet port of the condenser to the condenser inlet ports and (iii) flowing refrigerant from the condenser inlet ports to a suction side of the compressor. ### Claim 22 (depends on 21) The refrigeration system of claim 21 wherein the reversing conduits and valves comprise a four-way valve. ### Claim 23 (depends on 22) The refrigeration system of claim 22 wherein the reversing conduits and valves comprise a condenser warming line and a condenser warming line controller for controlling the warming of the condenser using refrigerant flowing from the evaporator to the outlet of the condenser. ### Claim 24 (depends on 23) The refrigeration system of claim 23 further comprising a heater disposed downstream of the evaporator for heating refrigerant flowing from the evaporator to the outlet of the condenser. ### Claim 25 (depends on 23) The refrigeration system of claim 23 further comprising a drop leg disposed downstream of the evaporator for separating out liquid refrigerant and oils from the refrigerant stream exiting the evaporator and a heater disposed downstream of the drop leg for heating such liquid refrigerant and oils separated out of the refrigerant exiting the evaporator and for flowing such refrigerant and oils separated out of the refrigerant to the outlet of the condenser. ### Claim 26 (depends on 12) The refrigeration system of claim 12 further comprising a drop leg disposed downstream of the evaporator for separating out liquid refrigerant and oils from the refrigerant stream exiting the evaporator and a heater disposed downstream of the drop leg for heating such liquid refrigerant and oils separated out of the refrigerant exiting the evaporator and for flowing such refrigerant and oils separated out of the refrigerant to the outlet of the condenser. ### Claim 27 A method of controlling a refrigeration system, wherein the refrigeration system comprises a refrigerant disposed within a fluid-tight circulation loop comprising a continuous length of tubing, the refrigeration system including a compressor, a condenser and an evaporator, the refrigerant being capable of existing in a liquefied state, a gaseous state and a two-phase state comprising both refrigerant in the liquefied state and refrigerant in the gaseous state, the evaporator having an outlet port and at least three evaporator zones in series provided by the continuous length of tubing, each evaporator zone having an (i) evaporator zone inlet port and (ii) an evaporator feed input control valve upstream of the inlet port, the method comprising the steps of: (a) compressing refrigerant in a gaseous state within the compressor and cooling the refrigerant within the condenser to yield refrigerant in the liquefied state; (b) flowing refrigerant from the condenser into the evaporator via the inlet port and the control valve of each evaporator zone, wherein the refrigerant partially exists in a two-phase state, and wherein refrigerant introduced into each evaporator zone through its inlet port and evaporator feed input control valve flows directly into the next evaporator zone in series until the refrigerant exits the evaporator through the outlet port in step (c); (c) flowing refrigerant from the evaporator to the compressor; d) measuring the condition of the refrigerant with a refrigerant condition sensor disposed within each of the evaporator zones; and e) controlling with a controller the flow rate of refrigerant to the evaporator in step (b) based upon the measured condition of the refrigerant condition of the refrigerant from step (d), wherein the controlling of the refrigerant flow rate to the evaporator is carried out by controlling the refrigerant flow rate to each of the evaporator zones with separate signals from the controller.