REFRIGERANT SYSTEM WITH CASCADED CIRCUITS AND PERFORMANCE ENHANCEMENT FEATURES
First Claim
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1. A refrigerant system comprising:
- at least one pair of circuits operated in a cascade fashion, with a first circuit including a first compressor compressing a refrigerant and delivering the refrigerant to a heat rejection heat exchanger, refrigerant passing from said heat rejection heat exchanger through an expansion device, and then to a refrigerant-to-refrigerant heat exchanger, refrigerant from said refrigerant-to-refrigerant heat exchanger being returned to said first compressor;
a second circuit, said second circuit including a second compressor, said second compressor delivering refrigerant to said refrigerant-to-refrigerant heat exchanger, refrigerant from said refrigerant-to-refrigerant heat exchanger passing through an expansion device, and then through said heat accepting heat exchanger;
said refrigerant-to-refrigerant heat exchanger providing heat transfer communication between said first circuit and said second circuit;
said first circuit utilizing a first refrigerant, and said second circuit utilizing a second refrigerant; and
at least one additional performance enhancement feature incorporated in at least one of said first circuit or said second circuit.
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Abstract
An improved refrigerant system incorporates at least two circuits arranged in a cascaded relationship. Preferably, the upper circuit utilizes a hydrocarbon refrigerant and preferably the lower circuit utilizes CO2 refrigerant. Preferably, the CO2 circuit mainly operates in a subcritical region. To improve the efficiency and capacity control of the cascaded refrigerant system, at least one of the circuits is equipped with performance enhancement features such as, for example, an economized function provided by a flash tank or economizer heat exchanger. Additional enhancement features can also include a liquid-suction heat exchanger and bypass function.
41 Citations
21 Claims
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1. A refrigerant system comprising:
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at least one pair of circuits operated in a cascade fashion, with a first circuit including a first compressor compressing a refrigerant and delivering the refrigerant to a heat rejection heat exchanger, refrigerant passing from said heat rejection heat exchanger through an expansion device, and then to a refrigerant-to-refrigerant heat exchanger, refrigerant from said refrigerant-to-refrigerant heat exchanger being returned to said first compressor; a second circuit, said second circuit including a second compressor, said second compressor delivering refrigerant to said refrigerant-to-refrigerant heat exchanger, refrigerant from said refrigerant-to-refrigerant heat exchanger passing through an expansion device, and then through said heat accepting heat exchanger; said refrigerant-to-refrigerant heat exchanger providing heat transfer communication between said first circuit and said second circuit; said first circuit utilizing a first refrigerant, and said second circuit utilizing a second refrigerant; and at least one additional performance enhancement feature incorporated in at least one of said first circuit or said second circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21-42. -42. (canceled)
Specification