# US 7,607,314 B2 · Air conditioning system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,314 B2 - Document ID: US7607314B2 - Status: Granted - Kind: B2 - Application number: 11/639,421 - Filed: 2006-12-15 - Published: 2008-06-19 - Granted: 2009-10-27 - Earliest claimed: 2006-12-15 - Assignees: Nissan Technical Center North America, Inc. - Inventors: Ronald S. Eisenhour - Web page: https://patentgrep.com/patent/US7607314B2 ## CPC - F25B 11/02: as expanders (F25B9/06 takes precedence) - F25B 1/04: with compressor of rotary type ({F25B1/005,} F25B1/10 take precedence) - F25B 2400/04: Refrigeration circuit bypassing means - F25B 2400/14: Power generation using energy from the expansion of the refrigerant - F25B 2700/1933: Suction pressures - F25B 2700/21175: of the refrigerant at the outlet of the evaporator - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract An air conditioning system includes an evaporator, a compressor, a condenser, a valve an energy recovery device and at least one bypass passage. The compressor is fluidly connected to the evaporator. The condenser is fluidly connected to the compressor. The valve is configured to control flow of high-pressure refrigerant exiting the condenser. The energy recovery device has an inlet and an outlet. The inlet is fluidly connected to the valve to receive high-pressure refrigerant and the outlet is fluidly connected to the evaporator to deliver low-pressure refrigerant thereto. The energy recovery device is configured to extract work from flow of refrigerant therethrough. When the valve is closed and refrigerant flow cutoff, suction power loss is reduced by introduction of one or both of high-pressure refrigerant or low pressure refrigerant via one or more bypass passages. ## Claims ### Claim 1 An air conditioning system comprising: an evaporator a compressor fluidly connected to the evaporator to compress low-pressure refrigerant exiting the evaporator to high-pressure refrigerant a condenser fluidly connected to the compressor to receive the high pressure refrigerant and dissipate heat therefrom; a valve configured to control flow of high pressure refrigerant exiting the condenser; an energy recovery device having a chamber with an inlet fluidly connected to the valve to receive high pressure refrigerant exiting the valve and an outlet fluidly connected to the evaporator to deliver low pressure refrigerant thereto, the energy recovery device being configured to extract work from flow of refrigerant therethrough; and a bypass passage fluidly connected to the chamber of the energy recovery device downstream from the inlet of the chamber and up stream from the outlet of the chamber the bypass passage being configured to deliver an auxiliary flow of refrigerant to the chamber of the energy recovery device to reduce suction power loss such that the auxiliary flow of refrigerant exits the outlet of the chamber with the refrigerant that was received in the inlet. ### Claim 2 (depends on 1) The air conditioning system as set forth in claim 1, wherein the energy recovery device includes a second bypass passage between the bypass passage and the outlet that is also configured to receive an auxiliary flow of refrigerant to reduce suction power loss within the energy recovery device. ### Claim 3 (depends on 1) The air conditioning system as set forth in claim 1, wherein the bypass passage is configured to receive a restricted flow of high pressure refrigerant downstream from the compressor and upstream from the valve. ### Claim 4 (depends on 1) The air conditioning system as set forth in claim 1, wherein the bypass passage is configured to receive low-pressure refrigerant from a downstream section of the air conditioning system downstream from the energy recovery device. ### Claim 5 (depends on 4) The air conditioning system as set forth in claim 4, further comprising: a check valve disposed between the bypass passage and the downstream section to regulate refrigerant flow to the bypass passage. ### Claim 6 (depends on 1) The air conditioning system as set forth in claim 1, wherein the energy recovery device is a vane type expander that includes a plurality of vanes, adjacent ones of the vanes being offset from one another by a prescribed angular distance. ### Claim 7 (depends on 6) The air conditioning system as set forth in claim 6, wherein the energy recovery device includes a plurality of bypass passages between the inlet and the outlet that are configured to receive corresponding auxiliary flows of refrigerant to reduce suction power loss within the energy recovery device. ### Claim 8 (depends on 7) The air conditioning system as set forth in claim 7, wherein the plurality of bypass passages are offset from one another within the energy recovery device by distances conforming to the angular offset between the adjacent ones of the vanes of the energy recovery device. ### Claim 9 (depends on 1) The air conditioning system as set forth in claim 1, wherein the valve is connected to a microcomputer that is further connected to at least one of a pressure sensor and a temperature sensor of the air conditioning system and is configured to control the flow of high-pressure refrigerant exiting the condenser and entering the energy recovery device. ### Claim 10 (depends on 1) The air conditioning system as set forth in claim 1, wherein the valve is connected to a relay that is further connected to a pressure sensor downstream of the energy recovery device, the relay being configured to open the valve in response to prescribed pressure conditions sensed by the pressure sensor. ### Claim 11 (depends on 1) The air conditioning system as set forth in claim 1, wherein the energy recovery device is configured to transfer work from expanding refrigerant flowing therethrough to the compressor. ### Claim 12 (depends on 1) The air conditioning system as set forth in claim 1, wherein the energy recovery device is configured to transfer work from expanding refrigerant flowing therethrough to a generator to produce electric current. ### Claim 13 An air conditioning system comprising: an evaporator; a compressor fluidly connected to the evaporator to compress low-pressure refrigerant exiting the evaporator to high-pressure refrigerant; a condenser fluidly connected to the compressor to receive the high pressure refrigerant and dissipate heat therefrom; a valve configured to control flow of high pressure refrigerant exiting the condenser; an energy recovery device having an inlet fluidly connected to the valve to receive high pressure refrigerant, an outlet fluidly connected to the evaporator to deliver low pressure refrigerant thereto, the energy recovery device being configured to extract work from flow of refrigerant therethrough; a bypass passage downstream from the inlet and upstream from the outlet of the energy recovery device, the bypass passage being configured to deliver an auxiliary flow of refrigerant to the energy recovery device to reduce suction power loss; and a high-pressure line configured to deliver high-pressure refrigerant from the compressor to the valve and a bypass line configured to deliver high-pressure refrigerant from the high-pressure line to the bypass passage. ### Claim 14 (depends on 13) The air conditioning system as set forth in claim 13, wherein the high-pressure line has a first internal diameter and the bypass line has a second internal diameter such that the second internal diameter and the first internal diameter are dimensioned with a ratio of approximately 1:100. ### Claim 15 An air conditioning system comprising: an evaporator; a compressor fluidly connected to the evaporator to compress low-pressure refrigerant exiting the evaporator to high-pressure refrigerant; a condenser fluidly connected to the compressor to receive the high pressure refrigerant and dissipate heat therefrom; a valve configured to control flow of high pressure refrigerant exiting the condenser; an energy recovery device having an inlet fluidly connected to the valve to receive high pressure refrigerant, an outlet fluidly connected to the evaporator to deliver low pressure refrigerant thereto, the energy recovery device being configured to extract work from flow of refrigerant therethrough; a bypass passage downstream from the inlet and upstream from the outlet of the energy recovery device, the bypass passage being configured to deliver an auxiliary flow of refrigerant to the energy recovery device to reduce suction power loss; and a low pressure line configured to deliver low pressure refrigerant from the energy recovery device to the evaporator and a bypass line configured to deliver low pressure refrigerant from the low pressure line downstream from the energy recovery device to the bypass passage. ### Claim 16 (depends on 15) The air conditioning system as set forth in claim 15, wherein the low-pressure line has a first internal diameter and the bypass line has a second internal diameter such that the first internal diameter and the second internal diameter are dimensioned with a ratio of approximately 2:1. ### Claim 17 (depends on 1) The air conditioning system as set forth in claim 1, wherein the bypass passage is configured to deliver auxiliary flow of refrigerant to the energy recovery device when the valve is closed. ### Claim 18 (depends on 13) The air conditioning system as set forth in claim 13, wherein the bypass passage is configured to deliver auxiliary flow of refrigerant to the energy recovery device when the valve is closed. ### Claim 19 (depends on 15) The air conditioning system as set forth in claim 15, wherein the bypass passage is configured to deliver auxiliary flow of refrigerant to the energy recovery device when the valve is closed. ### Claim 20 (depends on 1) The air conditioning system as set forth in claim 1, wherein the bypass passage is configured to deliver auxiliary flow of refrigerant to the energy recovery device when vapor pressure within the energy recovery device is lower than vapor pressure in a section of the air conditioning system downstream from the energy recovery device and upstream from the evaporator.