Refrigeration cycle apparatus and refrigerant circulation method

Patent metadata

Field	Value
Publication number	US-9612047-B2
Application number	US-201113583323-A
Country	US
Kind code	B2
Filing date	Jan 26, 2011
Priority date	Mar 31, 2010
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

An internal heat exchanger and a first flow control valve are connected in series between a condenser and a refrigerant inlet of an ejector. A gas refrigerant outlet of a gas-liquid separator is connected to a suction port of a compressor. A first bypass circuit connects a refrigerant outlet of the condenser to an intermediate pressure portion of the compressor via a second flow control valve and the internal heat exchanger. A second bypass circuit connects a refrigerant outlet of the internal heat exchanger to the liquid refrigerant outlet of the gas-liquid separator via a third flow control valve. While the second flow control valve is opened such that the refrigerant flows through the first bypass circuit, the fourth flow control valve is switched to be opened or closed, and the third flow control valve is switched to be closed or opened.

First claim

The invention claimed is:

1. A refrigeration cycle apparatus comprising:
a high-pressure-side refrigerant circuit in which a compressor, a condenser, an ejector, and a gas-liquid separator are connected in series with a refrigerant pipe;
a low-pressure refrigerant circuit in which a liquid refrigerant that has flowed out of the gas-liquid separator flows through a fourth flow control valve and an evaporator to a refrigerant suction portion of the ejector;
a compressor suction circuit that connects an upper outlet of the gas-liquid separator to a suction port of the compressor such that a gas refrigerant that has flowed out of the gas-liquid separator is suctioned into the compressor;
a first bypass circuit that connects a point between the condenser and the ejector of the high-pressure refrigerant circuit to an intermediate pressure portion of the compressor via a second flow control valve;
an internal heat exchanger that exchanges heat between a refrigerant whose pressure has been reduced at the second flow control valve of the first bypass circuit and a high-pressure refrigerant flowing in the high-pressure-side refrigerant circuit; and
a second bypass circuit that connects a point between a first flow control valve and the internal heat exchanger to a point between the fourth control valve and the evaporator of the low-pressure refrigerant circuit via a third flow control valve so as to allow the high-pressure refrigerant to take a bypass, the first flow control valve being disposed between the internal heat exchanger and the ejector;
wherein while the second flow control valve is opened such that the refrigerant flows through the first bypass circuit, the fourth flow control valve is switched to be opened or closed, and the third flow control valve is switched to be closed or opened, and
wherein when a detected value of an outdoor air temperature detector is equal to or higher than a first outdoor air temperature and is lower than a second outdoor air temperature that is higher than the first outdoor air temperature, an opening degree of the first flow control valve is controlled such that a difference between a detected value of a temperature detector provided at a refrigerant outlet of the internal heat exchanger of the high-pressure-side refrigerant circuit and a saturation temperature reaches a target degree of supercooling, the saturation temperature being calculated on the basis of a detected value of a pressure detector provided at an outlet of the compressor, and
when the detected value of the outdoor air temperature detector is lower than the first outdoor air temperature, the second flow control valve is controlled to be opened such that the refrigerant flows into the first bypass circuit.

2. The refrigeration cycle apparatus of claim 1 , further comprising:
abnormality detecting means that determines that there is an abnormality when a degree of refrigerant superheat is equal to or higher than a third setting value, the degree of refrigerant superheat being calculated on the basis of a difference between a temperature detector attached to the ejector suction portion and a temperature detector attached to an inlet of the evaporator;
wherein when the abnormality detecting means has detected an abnormality, the first flow control valve and the fourth flow control valve are fully closed and the third flow control valve is opened such that the refrigerant flows into the first bypass circuit.

3. The refrigeration cycle apparatus of claim 1 , further comprising:
an abnormality detecting means that determines that there is an abnormality when a rotation speed of the compressor is less than a predetermined rotation speed;
wherein when the abnormality detecting means has detected an abnormality, the first flow control valve and the fourth flow control valve are fully closed and the third flow control valve is opened such that the refrigerant flows into the second bypass circuit.

4. The refrigeration cycle apparatus of claim 1 , wherein an opening degree of the second flow control valve is controlled such that a degree of superheat at a discharge port of the compressor becomes to a preset value, the degree of superheat being obtained by calculating a difference between a detected value of a temperature detector attached to the discharge port of the compressor and a saturation temperature computed from a detected value of a pressure detector attached to the discharge port of the compressor.

5. The refrigeration cycle apparatus of claim 1 , wherein a flow rate of the fourth flow control valve is controlled such that a degree of refrigerant superheat at the refrigerant suction portion of the ejector becomes to a preset value.

6. The refrigeration cycle apparatus of claim 1 , wherein a second supercooler is provided in a circuit extending between an upstream outlet of the gas-liquid separator and a point where the refrigerant is suctioned into the compressor.

7. A refrigerant circulation method comprising the steps of:
forming a high-pressure-side refrigerant circuit in which a compressor, a condenser, an ejector, and a gas-liquid separator are connected in series with a refrigerant pipe;
forming a low-pressure refrigerant circuit in which a liquid refrigerant that has flowed out of the gas-liquid separator flows through a fourth flow control valve and an evaporator to a refrigerant suction portion of the ejector;
forming a compressor suction circuit that connects an upper outlet of the gas-liquid separator to a suction port of the compressor such that a gas refrigerant that has flowed out of the gas-liquid separator is suctioned into the compressor;
forming a first bypass circuit that connects a point between the condenser and the ejector of the high-pressure refrigerant circuit to an intermediate pressure portion of the compressor via a second flow control valve; and
forming a second bypass circuit that connects a point between a first flow control valve and an internal heat exchanger to a point between the fourth control valve and the evaporator of the low-pressure refrigerant circuit via a third flow control valve so as to allow a high-pressure refrigerant to take a bypass, the first flow control valve being disposed between the internal heat exchanger and the ejector, the internal heat exchanger being configured to exchange heat between a refrigerant whose pressure has been reduced at the second flow control valve and the high-pressure refrigerant flowing in the high-pressure-side refrigerant circuit;
wherein while the second flow control valve is opened such that the refrigerant flows through the first bypass circuit, the fourth flow control valve is switched to be opened or closed, and the third flow control valve is switched to be closed or opened, and
wherein when a detected value of an outdoor air temperature detector is equal to or higher than a first outdoor air temperature and is lower than a second outdoor air temperature that is higher than the first outdoor air temperature, an opening degree of the first flow control valve is controlled such that a difference between a detected value of a temperature detector provided at a refrigerant outlet of the internal heat exchanger of the high-pressure-side refrigerant circuit and a saturation temperature reaches a target degree of supercooling, the saturation temperature being calculated on the basis of a detected value of a pressure detector provided at an outlet of the compressor, and
when the detected value of the outdoor air temperature detector is lower than the first outdoor air temperature, the second flow control valve is controlled to be opened such that the refrigerant flows into the first bypass circuit.

8. A refrigeration cycle apparatus comprising:
a high-pressure-side refrige

Assignees

• Higashiiue Shinya
• Okazaki Takashi
• Nomoto So
• Minamisako Hirokazu
• Mitsubishi Electric Corp

Inventors

• Higashiiue Shinya
• Okazaki Takashi
• Nomoto So
• Minamisako Hirokazu

Classifications

• F25B47/025

  by reversing the cycle · CPC title

• Y10T29/49359

  Cooling apparatus making, e.g., air conditioner, refrigerator · CPC title

• F25B2400/16

  Receivers · CPC title

• F25B40/00

  Subcoolers, desuperheaters or superheaters · CPC title

• F25B2341/0012

  Ejectors with the cooled primary flow at high pressure · CPC title