Refrigeration cycle system with internal heat exchanger

Patent metadata

Field	Value
Publication number	US-9822994-B2
Application number	US-201314390869-A
Country	US
Kind code	B2
Filing date	Apr 19, 2013
Priority date	Apr 23, 2012
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

In a refrigeration cycle system, switching is allowed between a parallel operation mode and a series operation mode. In the parallel operation mode, a refrigerant, upon leaving a load side heat exchanger, parallelly flows through a high-pressure side passage of each of a first internal heat exchanger and a second internal heat exchanger and then flows into an expansion valve. In the series operation mode, the refrigerant, upon leaving the load side heat exchanger, flows through the high-pressure side passage of the first internal heat exchanger, further flows through the high-pressure side passage of the second internal heat exchanger, and then flows through a high-pressure side bypass pipe into the expansion valve.

First claim

The invention claimed is:

1. A refrigeration cycle system comprising:
a refrigerant circuit which includes a compressor, a load side heat exchanger, an internal heat exchanger, an expansion unit, and a heat source side heat exchanger connected by pipes, and through which a refrigerant circulates,
the internal heat exchanger including
a first internal heat exchanger in which the refrigerant, upon flowing through a high-pressure side passage, exchanges heat with the refrigerant, upon flowing through a low-pressure side passage,
a second internal heat exchanger in which the refrigerant, upon flowing through a high-pressure side passage, exchanges heat with the refrigerant, upon flowing through a low-pressure side passage,
a first high-pressure side flow switching device disposed between an outlet of the load side heat exchanger and one end of the high-pressure side passage of each of the first internal heat exchanger and the second internal heat exchanger,
a second high-pressure side flow switching device disposed between the expansion unit and other end of the high-pressure side passage of each of the first internal heat exchanger and the second internal heat exchanger,
a high-pressure side bypass pipe that branches off from a pipe connecting the first high-pressure side flow switching device and the high-pressure side passage of the second internal heat exchanger and that is connected between the second high-pressure side flow switching device and the expansion unit,
a third high-pressure side flow switching device provided to the high-pressure side bypass pipe, and
a controller that switches between
a parallel operation mode in which the refrigerant, upon leaving the load side heat exchanger, parallelly flows through the high-pressure side passages of the first internal heat exchanger and the second internal heat exchanger and then flows into the expansion unit, and
a series operation mode in which the refrigerant, upon leaving the load side heat exchanger, flows through the high-pressure side passage of the first internal heat exchanger, further flows through the high-pressure side passage of the second internal heat exchanger, and then flows through the high-pressure side bypass pipe into the expansion unit.

2. The refrigeration cycle system of claim 1 , wherein the internal heat exchanger further includes:
a first low-pressure side flow switching device disposed between an outlet of the heat source side heat exchanger and one end of the low-pressure side passage of each of the first internal heat exchanger and the second internal heat exchanger;
a second low-pressure side flow switching device disposed between the compressor and other end of the low-pressure side passage of each of the first internal heat exchanger and the second internal heat exchanger;
a low-pressure side bypass pipe that branches off from a pipe connecting the first low-pressure side flow switching device and the low-pressure side passage of the second internal heat exchanger and connects to the compressor; and
a third low-pressure side flow switching device provided to the low-pressure side bypass pipe, and
wherein switching is allowed between
a parallel operation mode in which the refrigerant, upon leaving the load side heat exchanger, parallelly flows through the high-pressure side passages of the first internal heat exchanger and the second internal heat exchanger and then flows into the expansion unit, and the refrigerant, upon leaving the heat source side heat exchanger, parallelly flows through the low-pressure side passages of the first internal heat exchanger and the second internal heat exchanger and then flows into the compressor, and
a series operation mode in which the refrigerant, upon leaving the load side heat exchanger, flows through the high-pressure side passage of the first internal heat exchanger, further flows through the high-pressure side passage of the second internal heat exchanger, and then flows through the high-pressure side bypass pipe into the expansion unit, and the refrigerant, upon leaving the heat source side heat exchanger, flows through the low-pressure side passage of the first internal heat exchanger, further flows through the low-pressure side passage of the second internal heat exchanger, and then flows through the low-pressure side bypass pipe into the compressor.

3. The refrigeration cycle system of claim 1 ,
wherein the internal heat exchanger further includes
a fourth high-pressure side flow switching device disposed between an inlet of the high-pressure side passage of the first internal heat exchanger and a bifurcation at which a pipe connecting to the outlet of the load side heat exchanger branches into a pipe connecting to the high-pressure side passage of the first internal heat exchanger and a pipe connecting to the high-pressure side passage of the second internal heat exchanger, and
wherein switching is allowed to a high-pressure bypass operation mode in which the refrigerant, upon leaving the load side heat exchanger, flows through the high-pressure side bypass pipe into the expansion unit without passing through the first internal heat exchanger and the second internal heat exchanger.

4. The refrigeration cycle system of claim 2 , wherein the internal heat exchanger further includes a fourth low-pressure side flow switching device disposed between an inlet of the low-pressure side passage of the first internal heat exchanger and a bifurcation at which a pipe connecting to the outlet of the heat source side heat exchanger branches into a pipe connecting to the low-pressure side passage of the first internal heat exchanger and a pipe connecting to the low-pressure side passage of the second internal heat exchanger, and wherein switching is allowed to a low-pressure bypass operation mode in which the refrigerant, upon leaving the heat source side heat exchanger, flows through the low-pressure side bypass pipe into the compressor without passing through the first internal heat exchanger and the second internal heat exchanger.

5. The refrigeration cycle system of claim 2 , wherein the internal heat exchanger further includes
a fourth high-pressure side flow switching device disposed between an inlet of the high-pressure side passage of the first internal heat exchanger and a bifurcation at which a pipe connecting to the outlet of the load side heat exchanger branches into a pipe connecting to the high-pressure side passage of the first internal heat exchanger and a pipe connecting to the high-pressure side passage of the second internal heat exchanger, and
a fourth low-pressure side flow switching device disposed between an inlet of the low-pressure side passage of the first internal heat exchanger and a bifurcation at which a pipe connecting to the outlet of the heat source side heat exchanger branches into a pipe connecting to the low-pressure side passage of the first internal heat exchanger and a pipe connecting to the low-pressure side passage of the second internal heat exchanger, and
wherein switching is allowed to a bypass operation mode in which the refrigerant, upon leaving the load side heat exchanger, flows through the high-pressure side bypass pipe into the expansion unit without passing through the first internal heat exchanger and the second internal heat exchanger, and the refrigerant, upon leaving the heat source side heat exchanger, flows through the low-pressure side bypass pipe into the compressor without passing through the first internal heat exchanger and the second internal heat exchanger.

6. The refrigeration cycle system of claim 1 , wherein the internal heat exchanger further includes
a fourth high-pressure side flow switching device disposed between an inlet of the high-pressure side passage of the first internal heat exchanger an

Assignees

• Mitsubishi Electric Corp

Inventors

• Yanachi Satoru
• Kato Yohei

Classifications

• F25B13/00 Primary

  Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) · CPC title

• F25B47/025

  by reversing the cycle · CPC title

• F25B2313/02741

  using one four-way valve · CPC title

• F25B2313/0272

  using bridge circuits of one-way valves · CPC title

• F25B49/02

  for compression type machines, plants or systems · CPC title