Evaporator unit and ejector type refrigeration cycle

Abstract

An evaporator unit includes an ejector, an upwind side heat exchanger for evaporating a discharge side refrigerant flowing from the ejector, and a downwind side heat exchanger for evaporating a suction side refrigerant to be drawn into the ejector. The ejector has a nozzle for decompressing refrigerant, and a refrigerant suction port, from which refrigerant is drawn by a high-speed flow of refrigerant jetted from the nozzle. The upwind side heat exchanger has a refrigerant superheat area, which is offset from a refrigerant superheat area of the downwind side heat exchanger in a direction perpendicular to an air flow to be cooled.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a schematic diagram showing an ejector type refrigeration cycle according to a first embodiment of the present invention;

FIG. 2 is a schematic perspective view showing an evaporator unit according to the first embodiment;

FIG. 3 is a schematic perspective view showing an evaporator unit according to a second embodiment;

FIG. 4 is a schematic perspective view showing an evaporator unit according to a third embodiment;

FIG. 5 is a schematic perspective view showing an evaporator unit according to a fourth embodiment;

FIG. 6 is a schematic diagram showing an ejector type refrigeration cycle according to a modification of the first embodiment;

FIG. 7 is a schematic diagram showing an ejector type refrigeration cycle according to another modification of the first embodiment; and

FIG. 8 is a graph showing a relationship between an occupancy rate of a downwind side heat exchanger and a refrigeration performance.

Claims

1. An evaporator unit comprising: an ejector having a nozzle for decompressing refrigerant, and a refrigerant suction port, from which refrigerant is drawn by a high-speed flow of refrigerant jetted from the nozzle;an upwind side heat exchanger located at an upwind side of air flow for exchanging heat with refrigerant, wherein the upwind side heat exchanger evaporates a discharge side refrigerant flowing out of an outlet of the ejector; anda downwind side heat exchanger located at a downwind side of the upwind side heat exchanger in the air flow, wherein at least a part of the downwind side heat exchanger evaporates a suction side refrigerant to be drawn into the refrigerant suction port of the ejector,the upwind side heat exchanger has a refrigerant superheat area, which is offset from a refrigerant superheat area of the downwind side heat exchanger in a direction perpendicular to the air flow.

2. The evaporator unit according to claim 1, wherein: the ejector is located inside of a header tank for gathering the discharge side refrigerant in the downwind side heat exchanger.

3. The evaporator unit according to claim 1, wherein: the refrigerant superheat area of the upwind side heat exchanger is offset from the refrigerant superheat area of the downwind side heat exchanger to prevent an overlap between the superheat areas in the air flow.

4. The evaporator unit according to claim 1, wherein: the upwind side heat exchanger and the downwind side heat exchanger are located such that a flowing direction of the discharge side refrigerant in the upwind side heat exchanger is opposite to a flowing direction of the suction side refrigerant in the downwind side heat exchanger in the air flow.

5. The evaporator unit according to claim 1, wherein: the upwind side heat exchanger has a heat exchanging portion, in which the discharge side refrigerant flows while changing its flowing direction once or more times.

6. The evaporator unit according to claim 1, wherein: the downwind side heat exchanger has a heat exchanging portion, in which the suction side refrigerant flows while changing its flowing direction once or more times.

7. The evaporator unit according to claim 1, wherein: the downwind side heat exchanger includes a first heat exchanging portion, in which the discharge side refrigerant flows, and a second heat exchanging portion in which the suction side refrigerant flows.

8. The evaporator unit according to claim 7, wherein: the downwind side heat exchanger includes a plurality of tubes extending in a tube longitudinal direction, first and second header tanks located at both end sides of the tubes to extend in a direction perpendicular to the tube longitudinal direction, and a separator member which is located in at least one of the first and second header tanks to separate the downwind side heat exchanger into the first heat exchanging portion and the second heat exchanging portion.

9. The evaporator unit according to claim 7, wherein: the first heat exchanging portion of the downwind side heat exchanger communicates with the upwind side heat exchanger such that the discharge side refrigerant flows through the first heat exchanging portion of the downwind side heat exchanger and the upwind side heat exchanger.

10. The evaporator unit according to claim 7, wherein: the second heat exchanging portion of the downwind side heat exchanger has an occupancy rate to the downwind side heat exchanger; andthe occupancy rate is in a range between 30% and 75%.

11. An ejector type refrigeration cycle including the evaporator unit according to claim 10, the cycle comprising: a compressor for compressing refrigerant;a radiator for radiating heat of a high-temperature and high-pressure refrigerant flowing from the compressor; andthe evaporator unit coupled with the compressor and the radiator, whereinthe evaporator unit has a flowing ratio of a flowing amount of the suction side refrigerant to a flowing amount of refrigerant discharged from the compressor, andthe flowing ratio is in a range between 0.3 and 0.7.

12. An ejector type refrigeration cycle, comprising: a compressor for compressing refrigerant;a radiator for radiating heat of a high-temperature and high-pressure refrigerant flowing from the compressor; andan evaporator unit which includes an ejector having a nozzle for decompressing refrigerant, and a refrigerant suction port from which refrigerant is drawn by a high-speed flow of refrigerant jetted from the nozzle,an upwind side heat exchanger located at an upwind side of air flow for exchanging heat with refrigerant, wherein the upwind side heat exchanger evaporates a discharge side refrigerant flowing out of an outlet of the ejector, anda downwind side heat exchanger located at a downwind side of the upwind side heat exchanger in the air flow, wherein at least a part of the downwind side heat exchanger evaporates a suction side refrigerant to be drawn into the refrigerant suction port of the ejector,the downwind side heat exchanger includes a first heat exchanging portion for evaporating the discharge side refrigerant, and a second heat exchanging portion for evaporating the suction side refrigerant,the evaporator unit has an occupancy rate of the second heat exchanging portion to the downwind side heat exchanger,the evaporator unit has a flowing ratio of a flowing amount of the suction side refrigerant to a flowing amount of refrigerant discharged from the compressor, andthe flowing ratio is set in accordance with the occupancy rate.

13. The evaporator unit according to claim 12, wherein: the downwind side heat exchanger includes a plurality of tubes extending in a tube longitudinal direction, first and second header tanks located at both end sides of the tubes to extend in a direction perpendicular to the tube longitudinal direction, and a separator member which is located in at least one of the first and second header tanks to separate the downwind side heat exchanger into the first heat exchanging portion and the second heat exchanging portion.