BRAYTON CYCLE TYPE REFRIGERATING APPARATUS

• US 20160018134A1
• Filed: 03/20/2014
• Published: 01/21/2016
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Mayekawa Manufacturing Company Limited (Mayekawa Holding AG)
• Original Assignee: Mayekawa Manufacturing Company Limited (Mayekawa Holding AG)
• Inventors: UEDA, Shota, MACHIDA, Akito, KUDO, Mizuo, NAKAMURA, Naoko
• Granted Patent: US 9,863,669 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02C 1/10 Closed cycles
• CPC Class Codes: F25B 1/10 with multi-stage compression with cascade operation F25B7/00
• CPC Class Codes: F25B 11/02 as expanders F25B9/06 takes precedence
• CPC Class Codes: F25B 2345/006 characterised by charging or discharging valves
• CPC Class Codes: F25B 2500/23 High amount of refrigerant in the system
• CPC Class Codes: F25B 2500/24 Low amount of refrigerant in the system
• CPC Class Codes: F25B 2600/2523 Receiver valves
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 2700/21163 of the refrigerant at the outlet of the condenser
• CPC Class Codes: F25B 2700/21172 at the inlet
• CPC Class Codes: F25B 40/00 Subcoolers, desuperheaters or superheaters
• CPC Class Codes: F25B 45/00 Arrangements for charging or discharging refrigerant
• 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

To provide a Brayton cycle type refrigerating apparatus using multiple stages of compressors and having a good response without reduction in efficiency due to change in heat load of the object to be cooled, the Brayton cycle type refrigerating apparatus (100) according to the present invention comprises, on a refrigerant line (101), multiple stages of compressors (102a, 102b, 102c), a temperature sensor (160) for detecting heat load of an object to be cooled, and a buffer tank (111) provided between a low pressure line (109) and a high pressure line (110), wherein a flow rate of the refrigerant in the refrigerant line is controlled by controlling opening degrees of valves (112, 113) to adjust the cooling capacity.

Claims

1. A Brayton cycle type refrigerating apparatus utilizing a Brayton cycle having multiple stages of compressors arranged in series on a refrigerant line for generating cool heat by using a refrigerant compressed by the compressors to cool a secondary refrigerant, comprising:

a heat load detecting device for detecting a heat load of an object to be cooled;

a buffer tank provided between a low pressure line in which the refrigerant before being compressed by the compressors flows and a high pressure line in which the refrigerant after being compressed by the compressors flows;

a first valve provided on an inlet side of the buffer tank and capable of controlling an inflow rate of the refrigerant into the buffer tank;

a second valve provided on an outlet side of the buffer tank and capable of controlling an outflow rate of the refrigerant from the buffer tank; and

a control device for controlling an opening degree of the first valve and an opening degree of the second valve,

wherein the control device is configured, when a change in the heat load of the object to be cooled is detected by the heat load detecting device, to adjust the opening degree of the first valve and the opening degree of the second valve to change a flow rate of the refrigerant flowing in the Brayton cycle.

2. The Brayton cycle type refrigerating apparatus according to claim 1,

wherein the high pressure line is a line to which the refrigerant is discharged from a compressor disposed at the lowermost stream position among the compressors, and

wherein the low pressure line is a line through which the refrigerant is supplied to a compressor disposed at the uppermost stream position among the compressors.

3. The Brayton cycle type refrigerating apparatus according to claim 2, further comprising a cool heat recovering heat exchanger for exchanging heat between the refrigerant compressed by the compressors and the refrigerant after cooling the object to be cooled,

wherein the high pressure line has a branching line branched from a position between the at least one of the compressors and the cold heat recovering heat exchanger.

4. The Brayton cycle type refrigerating apparatus according to claim 1, wherein the control device is configured, when the change rate of the heat load detected by the heat load detecting device is greater than a preliminarily set prescribed value, to control a rotational speed of at least one of the compressors and a rotational speed of an expander, and then to adjust the opening degree of the first valve and the opening degree of the second valve.

5. The Brayton cycle type refrigerating apparatus according to claim 1,

wherein a cooling part of the Brayton cycle is configured to cool, by means of a heat exchanger, a secondary refrigerant circulating through the object to be cooled, and

wherein the heat load detecting device comprises a temperature sensor provided on a line in which the secondary refrigerant flows.

6. The Brayton cycle type refrigerating apparatus according to claim 1,

wherein the multiple stages of compressors comprise a first compressor, a second compressor and a third compressor, arranged in series in this order from the upstream side,

wherein the first compressor and the second compressor are connected to an output shaft of a first electric motor, and

wherein the third compressor and the expander are connected to an output shaft of a second electric motor.