CASCADE HEAT PUMP

• US 20130180276A1
• Filed: 01/10/2013
• Published: 07/18/2013
• Est. Priority Date: 01/10/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: Jaeheuk Choi
• Inventors: Kwak, Taehee, Yoo, Yoonho, Choi, Jaeheuk
• Granted Patent: US 9,759,454 B2
• Time in Patent Office: Days
• US Class Current: 62/190
• CPC Class Codes: F25B 1/10 with multi-stage compression with cascade operation F25B7/00
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2400/13 Economisers
• CPC Class Codes: F25B 7/00 Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit F25B9/00 takes precedence

Abstract

Provided is a cascade heat pump. The cascade heat pump includes a first refrigerant cycle including a first compressor and a first indoor heat exchanger, a second refrigerant cycle including a second compressor and a second indoor heat exchanger, an outdoor heat exchanger in which a refrigerant compressed in the first compressor or the second compressor is condensed, a bypass tube allowing the refrigerant compressed in the second compressor to bypass the first compressor, thereby flowing into a discharge side of the first compressor, and a first flow rate regulating part disposed on a discharge side of the second compressor to introduce the refrigerant discharged from the second compressor into one of the first compressor and the bypass tube.

Claims

1. A cascade heat pump comprising:

a first refrigerant cycle comprising a first compressor and a first indoor heat exchanger;

a second refrigerant cycle comprising a second compressor and a second indoor heat exchanger;

an outdoor heat exchanger in which a refrigerant compressed in the first compressor or the second compressor is condensed;

a bypass tube allowing the refrigerant compressed in the second compressor to bypass the first compressor, thereby flowing into a discharge side of the first compressor; and

a first flow rate regulating part disposed on a discharge side of the second compressor to introduce the refrigerant discharged from the second compressor into one of the first compressor and the bypass tube.

2. The cascade heat pump according to claim 1, wherein the bypass tube has one end connected to the first flow rate regulating part and the other end connected to the discharge side of the first compressor.

3. The cascade heat pump according to claim 1, further comprising a third refrigerant cycle disposed on a side of the first refrigerant cycle or the second refrigerant cycle, the third refrigerant cycle comprising a third compressor and a third indoor heat exchanger to perform a cooling or heating operation.

4. The cascade heat pump according to claim 3, wherein the third refrigerant cycle comprises a refrigerant heat exchanger in which the refrigerant discharged from the outdoor heat exchanger and the refrigerant circulating into the third refrigerant cycle are heat-exchanged with each other.

5. The cascade heat pump according to claim 4, wherein the third refrigerant cycle further comprises a third outdoor heat exchanger disposed on a side of the refrigerant heat exchanger to heat-exchange the refrigerant circulating into the third refrigerant cycle with external air.

6. The cascade heat pump according to claim 3, wherein the third refrigerant cycle further comprises:

a third expander disposed on a side of the third indoor heat exchanger to decompress the refrigerant; and

a fourth expander disposed on a side of the refrigerant heat exchanger to decompress the refrigerant.

7. The cascade heat pump according to claim 1, wherein the second refrigerant cycle comprises:

a supercooling heat exchanger in which at least one portion of the refrigerant condensed in the outdoor heat exchanger is introduced and heat-exchanged; and

a supercooling expander for expanding at least one portion of the refrigerant introduced into the supercooling heat exchanger.

8. The cascade heat pump according to claim 1, further comprising:

a first refrigerant tube disposed in the first refrigerant cycle to guide a flow of the refrigerants circulating into the first compressor and the first indoor heat exchanger; and

a second refrigerant tube disposed in the second refrigerant cycle to guide a flow of the refrigerants circulating into the second compressor and the second indoor heat exchanger.

9. The cascade heat pump according to claim 8, wherein the first refrigerant tube comprises:

a first branch part for branching at least one portion of the refrigerant passing through the outdoor heat exchanger into the second refrigerant tube; and

a first joint part by which the refrigerant passing through the second indoor heat exchanger flows into the first refrigerant tube.

10. The cascade heat pump according to claim 9, wherein the first flow rate regulating part is disposed between a discharge end of the second compressor and the first joint part.

11. The cascade heat pump according to claim 7, wherein the first refrigerant cycle comprises:

a second branch part for introducing at least one portion of the refrigerant condensed in the outdoor heat exchanger into the supercooling expander; and

a second joint part by which the refrigerant passing through the supercooling heat exchanger flows into the first refrigerant tube of the first refrigerant cycle.

12. The cascade heat pump according to claim 1, further comprising:

an equilibrium pressure tube extending from a discharge side of the first flow rate regulating part to the discharge side of the first compressor to allow the refrigerant to bypass the first compressor; and

a second flow rate regulating part for adjusting an opened degree of the equilibrium pressure tube.

13. The cascade heat pump according to claim 12, further comprising a control part for controlling an opened degree of each of the first flow rate regulating part and the second flow rate regulating part,

wherein the control part controls the first flow rate regulating part so that the refrigerant flows into the bypass tube and closes the second flow rate regulating part when external air has a temperature less than a preset temperature, and

the control part controls the first flow rate regulating part so that the refrigerant is compressed in two stages in the second compressor and the first compressor and opens the second flow rate regulating part when the external air has a temperature greater than the preset temperature.

14. The cascade heat pump according to claim 12, further comprising a suction pressure detection part for detecting a suction side pressure of the first compressor;

and

a discharge pressure detection part for detecting a discharge side pressure of the first compressor,

when a difference between the discharge side pressure and the suction side pressure of the first compressor is less than a preset pressure, the second flow rate regulating part is closed.

15. The cascade heat pump according to claim 12, wherein the first flow rate regulating part comprises a four-way valve, and the second flow rate regulating part comprises a check valve.

16. A cascade heat pump comprising:

a refrigerating cycle comprising a refrigerating compressor and a refrigerating indoor heat exchanger;

a freezing cycle comprising a freezing compressor and a freezing indoor heat exchanger;

an outdoor heat exchanger in which a refrigerant compressed in the refrigerating compressor or the freezing compressor is condensed;

an air-conditioning cycle comprising an air-conditioning compressor and an air-conditioning indoor heat exchanger;

a refrigerant heat exchanger disposed on a side of the outdoor heat exchanger to heat-exchange the refrigerant condensed in the outdoor heat exchanger with a refrigerant circulating into the air-conditioning cycle; and

a first flow rate regulating part disposed on a discharge side of the freezing compressor to adjust a flow direction of the refrigerant so that the refrigerant compressed in the freezing compressor is compressed in two stages in the refrigerating compressor.

17. The cascade heat pump according to claim 16, further comprising a bypass tube connected to the first flow rate regulating part to guide the refrigerant so that the refrigerant compressed in the freezing compressor bypasses the refrigerating compressor.

18. The cascade heat pump according to claim 17, further comprising an equilibrium pressure tube connected to a discharge side of the first flow rate regulating part so that at least one portion of the refrigerant to be introduced into the refrigerating compressor is bypassed.

19. The cascade heat pump according to claim 18, further comprising a second flow rate regulating part disposed in the equilibrium pressure tube to selectively block a flow of the refrigerant.

20. The cascade heat pump according to claim 16, further comprising:

an external air detection part for detecting a temperature of external air; and

a control part controlling the first flow rate regulating part to compress the refrigerant in two stages when the external air temperature detected by the external air temperature detection part is greater than a preset temperature.