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  Cooling systemsUSPTO Application #: 20060064997Title: Cooling systems Abstract: An apparatus has a compressor having suction and discharge ports. One or more conduits form a main flowpath from the discharge port through a condenser, a heat exchanger first leg, a first expansion device, and an evaporator to return to the suction port. The conduits also form a bypass flowpath bypassing the heat exchanger first leg, the first expansion device, and the evaporator but passing through a second leg of the heat exchanger in heat exchange relation with the first leg. (end of abstract)
Agent: Bachman & Lapointe, P.C. - New Haven, CT, US Inventor: Michal K. Grabon USPTO Applicaton #: 20060064997 - Class: 062197000 (USPTO) Related Patent Categories: Refrigeration, Automatic Control, Refrigeration Producer, Bypass, E.g., Compressor Unloading, Of Expansion Zone The Patent Description & Claims data below is from USPTO Patent Application 20060064997. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] The invention relates to cooling systems. More particularly, the invention relates to the control of refrigerant phase in evaporators of air conditioning and refrigeration systems. [0002] Many engineering considerations attend the design and operation of closed air conditioning and refrigeration systems. Among these are a variety of efficiency and other considerations attendant to evaporator operation. Proper evaporator operation is important for obtaining efficient and reliable system operation. Considerations include the handling of refrigerant and the management of heat transfer. Among problems that must be managed is excessive icing as this may interfere with heat transfer. Accordingly, much effort has gone into evaporator design and engineering. [0003] A particular area of emphasis has been the engineering of distributor systems. A distributor receives two-phase refrigerant from the expansion device and provides balanced delivery of liquid and gas refrigerant phases among the various coils of an evaporator so as to prevent uneven performance. Various types of distributors have been developed. These include capillary-type distributors and impingement/turbulence distributors. Exemplary distributors are shown in U.S. Pat. Nos. 2,148,414, 2,461,876, 3,795,259, 4,543,802, 5,832,744, and 5,842351, EP 0160542, and JP 5-322378 and 10-185363. [0004] Nevertheless there remains room for further improvement in the art. SUMMARY OF THE INVENTION [0005] One aspect of the invention involves an apparatus including a compressor having suction and discharge ports, a condenser, first and second expansion devices, an evaporator, and a heat exchanger having first and second portions in heat exchange relation with each other. One or more conduits form a main flowpath and a bypass flowpath. The main flowpath runs from the discharge port through the condenser, the heat exchanger first portion, the first expansion device, and the evaporator, and returns to the suction port. The bypass flowpath bypasses the heat exchanger first portion, the first expansion device, and the evaporator, but passes through the second expansion device and the heat exchanger second portion. [0006] In various implementations, the evaporator may lack a distributor. The second expansion device may be a TXV having a bulb essentially in heat exchange relation with a suction port condition. The second expansion device may be an EXV. A controller may be coupled to the EXV and programmed to control the EXV responsive to indicated superheat. The heat exchanger first portion may be downstream of the condenser and upstream of the evaporator along the main flowpath. The heat exchanger second portion may be downstream of the condenser along the bypass flowpath. The heat exchanger first portion may be upstream of the first expansion device along the main flowpath. The evaporator may be a refrigerant-to-air heat exchanger. In at least a bypass mode, a bypass flow along the bypass flowpath may enter the heat exchanger second portion in a two-phase gas/liquid condition and exit the heat exchanger second portion in a single-phase superheated gas condition. In the bypass mode, a main flow along the main flowpath may remain essentially a single-phase liquid in said heat exchanger second portion. The compressor may be selected from the group consisting of screw compressors and scroll compressors. [0007] Another aspect of the invention involves a method for operating such an apparatus. At least one operational parameter is detected. Responsive to the detection, at least the second expansion device is operated so as to maintain essentially single-phase liquid refrigerant entering the evaporator along the main flowpath. The at least one operational parameter may include at least one of saturated suction temperature and actual suction temperature. [0008] Another aspect of the invention involves a method for operating a cooling system. A main flow of refrigerant is caused to pass through an evaporator. The main flow is precooled upstream of the evaporator so as to maintain the main flow essentially as a liquid entering the evaporator. The precooling may comprise controlling a bypass flow in heat exchange relation with the main flow. The method may further comprise determining whether, absent the precooling, the main flow would enter the evaporator essentially as a two-phase flow. [0009] Another aspect of the invention involves a system comprising a compressor, a condenser, an expansion device, and an evaporator, a discharge line couples the compressor to the condenser to carry at least a main flow of refrigerant from the compressor to the condenser. A suction line couples the evaporator to the compressor to carry refrigerant from the condenser to the compressor. The system includes means for precooling refrigerant entering the expansion device so as to maintain the main flow essentially as a liquid while flowing along a flowpath length at least from the expansion device to the evaporator. [0010] In various implementations, the evaporator may lack a distributor. Within the evaporator, the main flow may transition to a two-phase liquid/gas flow and then to a one-phase superheated gas flow. The bypass flow may represent 10%-35%, by weight, of a total refrigerant flow through the compressor. [0011] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a schematic representation of a refrigeration or air conditioning system employing the present invention. [0013] FIG. 2 is a phase diagram for a prior art system. [0014] FIG. 3 is a phase diagram for the system of FIG. 1. [0015] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION [0016] FIG. 1, shows an exemplary closed refrigeration or air conditioning system 10. The system 10 has a hermetic compressor 12, from which a compressor discharge conduit or line 14 extends downstream to a condenser 16. An intermediate line 18 extends downstream from the condenser 16 to an expansion device 20 and an evaporator 22. A suction line 24 extends downstream from the evaporator 22 to the compressor 12 to complete the main circuit/flowpath 26. [0017] To form a bypass circuit/flowpath 28, a bypass line 30 branches off from the intermediate line 18 and contains an auxiliary expansion device 32 and connects with the suction line 24. A heat exchanger 34 is located such that the bypass line 30, downstream of the expansion device 32, and the line 18, upstream of the main expansion device 20, are in heat exchange relationship. [0018] The exemplary evaporator 22 is a cross-flow refrigerant-to-air heat exchanger having a number of parallel refrigerant coils 36 extending from inlet ends at a liquid collector or manifold 38 to outlet ends at a suction collector or manifold 40. A fan 42 drives an airflow 44 across the coils 36 so that the refrigerant passing through the coils may draw heat from the airflow. [0019] Exemplary expansion devices 20 and 32 are electronic expansion valves (EEVs) and are illustrated as coupled to a monitoring/control system 44 (e.g., a microprocessor-based controller) for receiving control inputs via control lines 45 and 46, respectively. The exemplary control system 44 may receive inputs such as zone inputs from one or more sensors 47, system condition inputs from one or more sensors (e.g., suction temperature sensor 50 and suction pressure sensor 52), and external control inputs from one or more input devices (e.g., thermostats 60). [0020] Alternatively to the EEVs, any of a variety of expansion devices may be used (e.g., a thermal expansion valve (TXV) 32 having a remote bulb 70, a fixed orifice device, or a capillary tube device). Continue reading... Full patent description for Cooling systems Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Cooling systems patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Cooling systems or other areas of interest. ### Previous Patent Application: Variable speed, electronically controlled, room air conditioner Next Patent Application: Inverter-integrated motor for an automotive vehicle Industry Class: Refrigeration ### FreshPatents.com Support Thank you for viewing the Cooling systems patent info. IP-related news and info Results in 0.79481 seconds Other interesting Feshpatents.com categories: Qualcomm , Schering-Plough , Schlumberger , Seagate , Siemens , Texas Instruments , |
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