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US 2003/0196445 A1Published application
Variable capacity refrigeration system with a single-frequency compressor
AssigneeVai Holdings, LLC
InventorsYoung I. Cho, Cheolho Bai
Life of this patent
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AssigneeVai Holdings, LLC
InventorsYoung I. Cho, Cheolho Bai
Estimating the term…
A variable capacity refrigeration system which does not require a costly inverter compressor and does not exhibit low energy efficiency at high capacity. The system employs a constant speed compressor that operates continuously when the system is energized, irrespective of the heat load, and a refrigerant bypass path including a secondary expansion device, a heat exchanger, and a flow control device which is operable to permit a portion of the refrigerant exiting from the condenser to flow through the bypass path to an inlet of the compressor when the heat load is below a predetermined threshold, whereby the heat exchanger operates as a secondary evaporator, and to prevent refrigerant exiting from the condenser from flowing through the bypass path to the compressor inlet when the heat load is not below the predetermined threshold. In one embodiment, the flow control device is further operable to permit a portion of the refrigerant exiting from the compressor to flow through the bypass path to the primary evaporator through the primary expansion device when the heat load is not below the predetermined threshold, whereby the heat exchanger operates as a secondary condenser. In several embodiments, a pressure differential is maintained between the refrigerant in the heat exchanger and the evaporator. The pressure differential is accommodated by a vacuum generating device such as a vortex generator, a venturi or the like, or by a flow restrictor such as a capillary tube. In several embodiments, the heat exchanger is thermally coupled to the compressor to remove heat from the refrigerant as it flows through the compressor.
A variable cooling capacity refrigeration system comprising:
A variable cooling capacity refrigeration system comprising:
A method of operating a refrigeration system to improve the SEER, the refrigeration system being comprised of a compressor, a condenser, an expansion device and an evaporator, all connected in a closed system with refrigerant flowing therethrough, the method comprising the steps of:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
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With compressor of jet type, e.g. using liquid under pressure: using vapour under pressure
Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity: arranged in parallel
Compression machines, plants or systems, with several condenser circuits: arranged in parallel
Fluid-circulation arrangements: disposition of valves, e.g. of on-off valves or flow control valves
Term end not estimated
The present invention relates generally to a high efficiency refrigeration system and, more specifically, to a refrigeration system utilizing a single-frequency compressor without ON-OFF operation for variable thermal load for increasing the overall efficiency of a refrigeration system.
FIG. 1 is a block diagram of a conventional refrigeration system, generally denoted at 10. The system includes a compressor 12, a condenser 14, an expansion device 16 and an evaporator 18. The various components are connected together via copper tubing such as indicated at 20 to form a closed loop system through which a refrigerant such as R-12, R-22, R-134a, R-407c, R-410a, ammonia, carbon dioxide or natural gas is cycled.
The main steps in the refrigeration cycle are compression of the refrigerant by compressor 12, heat extraction from the refrigerant to the environment by condenser 14, throttling of the refrigerant in the expansion device 16, and heat absorption by the refrigerant from the space being cooled in evaporator 18. This process, sometimes referred to as a vapor-compression refrigeration cycle, is used in air conditioning systems, which cool and dehumidify air in a living space, or vehicle (e.g., automobile, airplane, train, etc.), in refrigerators and in heat pumps.
FIG. 1 shows a block diagram of a conventional refrigeration system.
FIG. 2 shows a temperature-entropy curve for the conventional refrigeration system of FIG. 1.
FIG. 3 shows a typical performance curve of a heat absorption vs. frequency for a conventional inverter compressor.
Throughout the drawings, like parts are given the same reference numerals.
Turning now to FIGS. 5-7, there is illustrated a variable capacity refrigeration system according to a first embodiment of the invention. The system of FIG. 5, generally denoted at 40, includes a compressor 12, a condenser 14, an expansion device 16 and an evaporator 18. The indicated components, which may be identical to those described in connection with FIG. 1, are connected together via copper tubing such as indicated at 20 to form a closed loop system including a pressure differential accommodating device such as a vortex generator 52 or the like, as described below. A refrigerant such as R-12, R-22, R-134a, R-407c, R-410a, ammonia, carbon dioxide or natural gas is cycled through the system. A suitable combination of refrigerants may also be employed, as well as regeneration, as disclosed, for example, in our U.S. Pat. Nos. 6,250,086 and 6,293,108, the contents of which are hereby incorporated by reference.
Compressor 12 is continuously operated by a suitable power source such as an electric motor at a constant speed, for example, 60 Hz.