Patent Application
20190154323
The present application and the resultant patent relate generally to refrigeration systems and more particularly relate to systems and methods for operating a compressor rack in a refrigeration system at low load conditions for an extended period of time.
Modern air conditioning and refrigeration systems provide cooling, ventilation, and humidity control for all or part of a climate controlled area such as a refrigerator, a cooler, a building, and the like. Generally described, a conventional refrigeration cycle includes four basic stages to provide cooling. First, a vapor refrigerant is compressed within one or more compressors at high pressure and high temperature. Second, the compressed vapor is cooled and condensed within a condenser by heat exchange with ambient air drawn or blown against a condenser coil. Third, the liquid refrigerant is passed through an expansion device that reduces both the pressure and the temperature. The liquid refrigerant is then pumped to one or more evaporators within the climate controlled area. The liquid refrigerant absorbs heat from the surrounding area in an evaporator coil and evaporates to a vapor. Finally, the vapor refrigerant returns to the compressor and the cycle repeats. Several alternatives to this basic refrigeration cycle are known and also may be used herein.
When the load on the overall refrigeration system is low, the compressor racks may be unloaded to match the low load. If the load, however, is lower than the minimum capacity output of the compressor rack, then the compressors may stop and start frequently. Such frequent action may cause damage to the compressors as well as disrupt the overall system oil return.
The present application and the resultant patent thus provide a low load operating system for a refrigeration system having a compressor, a condenser, an expansion valve, and an evaporator. The low load operating system may include a hot gas bypass line extending from a discharge side of the compressor to a suction side of the compressor and a desuperheat line extending from upstream of the expansion valve to the suction side of the compressor.
The present application and the resultant patent further provide a method of operating a compressor in low load conditions. The method may include the steps of monitoring the compressor, determining if the low load conditions are present on the compressor, opening a hot gas bypass line to the compressor, opening a desuperheat line to the compressor, and periodically opening an oil return line. The valves then may be closed and the steps repeated.
The present application and the resultant patent further provide a refrigeration system. The refrigeration system may include a compressor rack, a hot gas bypass line extending from a discharge side of the compressor rack to a suction side of the compressor rack, a condenser, an expansion valve, a desuperheat line extending from upstream of the expansion valve to the suction side of the compressor rack, and an evaporator.
These and other features and improvements of the present application and the resultant patent will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.
Referring now to the drawings, in which like numerals refer to like elements throughout the several views.
The refrigeration system 10 may include one or more compressor racks 20. Each compressor rack 20 may include any number of compressors 25 thereon. The compressors 25 may be of conventional design and may have any suitable size, shape, configuration, or capacity. The compressor racks 20 and/or the compressors 25 may be arranged in a parallel configuration or a series configuration. The compressor rack 20 and each of the compressors 25 may include a suction side 30 and a discharge side 35. The compressors 25 may accept the flow of refrigerant 15 at the suction side, compress the flow therein, and discharge the flow on the discharge side 35. An oil separator 40 and the like may be positioned downstream of the discharge side 35. The oil separator 40 may separate a flow of oil in the refrigerant 15 due to compression within the compressors 25.
The refrigeration system 10 may include a condenser 45 positioned downstream of the compressor racks 20. The condenser 45 may be of conventional design and may have any suitable size, shape, configuration, or capacity. The condenser 45 may pull in ambient air for heat exchange with the refrigerant 15. The now liquid refrigerant 15 then may be stored in a receiver 50 and the like. A filter 55 and other components may be positioned downstream of the receiver 50. The receiver 50 and the filter 55 may be of conventional design.
The refrigeration system 10 may include an expansion valve 60. The expansion valve 60 may be positioned downstream of the receiver 50. The expansion valve 60 may reduce the pressure and the temperature of the flow of refrigerant 15 therethrough. The expansion valve 60 may be of conventional design and may have any suitable size, shape, configuration, or capacity.
The refrigeration system 10 may include one or more evaporators 65 positioned downstream of the expansion valve 60. The evaporators 65 may be positioned within or adjacent to the refrigerated space for heat exchange therewith. The evaporators 65 may be of conventional design and may have any suitable size, shape, configuration, or capacity. The refrigerant 15 then may return to the compressor racks 20 so as to repeat the cycle. Other components and other configurations may be used herein.
Operation of the refrigeration system 10 and components thereof may be controlled and monitored by a controller 70. The controller 70 may be any type of programmable logic device and the like. More than one controller 70 may be used herein. The controller 70 may be local or remote. The refrigeration system 10 and the components described herein are for the purpose of example only. Many other types of refrigeration systems, refrigeration cycles, and refrigeration components may be known and used herein.
The refrigeration system 100 may include a low load operating system 110. The low load operating system 110 may include a hot gas bypass line 120. The hot gas bypass line 120 may extend from downstream of the discharge side 35 of the compressors 25 to upstream of the suction side 30 of the compressors 25. The hot gas bypass line 120 may include a hot gas bypass line solenoid valve 130 and a hot gas bypass line flow valve 140. The hot gas bypass line solenoid valve 130 may be any type of on/off valve. The hot gas bypass line solenoid valve 130 may be in communication with the controller 70 and the like. The hot gas bypass line flow valve 140 may be any type of valve that controls the flow of the refrigerant 15 therethrough. The hot gas bypass line flow valve 140 also may be manually operated together with the solenoid valve 130. Other components and other configurations may be used herein.
The low load operating system 110 also may include a desuperheat line 150. The desuperheat line 150 may extend from upstream of the expansion valve 60 to upstream of the suction side 30 of the compressors 25 so as to bypass the evaporator 65. The desuperheat line 150 may include a desuperheat line solenoid valve 160 and a desuperheat line flow valve 170. As described above, the desuperheat line solenoid valve 160 may be any type of on/off valve. The desuperheat line solenoid valve 160 may be in communication with the controller 70. The desuperheat line flow valve 170 may be any type of valve that controls the flow of the refrigerant 15 therethrough. The desuperheat line flow valve 170 also may be manually operated together with the solenoid valve 160. Other components and other configurations may be used herein.
The low load operating system 110 may include an oil return line 180. The oil return line 180 extends from downstream of the oil separator 40 to upstream of the evaporator 65. An oil return line solenoid valve 190 may be positioned thereon. The solenoid valve 190 may be any type of on/off valve. The solenoid valve 190 may be in communication with the controller 70. Other components and other configurations may be used herein.
The low load operating system 110 may include one or more pressure sensors 200. The pressure sensors 200 may be in communication with the suction side 30 of the compressors 25 and the controller 70. The pressure sensors 200 may be of conventional design. Other types of sensors and other positions also may be used herein. Other components and other configurations may be used herein.
The refrigeration system 100 with the low load operating system 110 thus may avoid frequent starts and stops of the compressors 25 during low load operations. Likewise, the low load operating system 110 provides for oil return during these conditions. The low load operating system 110 thus may extend the useful lifetime of the refrigeration system 100 and the components thereof, particularly the compressors 25 and related components.
It should be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.
This application is a continuation of U.S. patent application Ser. No. 14/927,543, filed on Oct. 30, 2015. U.S. patent application Ser. No. 14/927,543 is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14927543 | Oct 2015 | US |
| Child | 16260805 | US |
