Refrigeration cycle device

Patent metadata

Field	Value
Publication number	US-12398936-B2
Application number	US-202118273777-A
Country	US
Kind code	B2
Filing date	Feb 2, 2021
Priority date	Feb 2, 2021
Publication date	Aug 26, 2025
Grant date	Aug 26, 2025

Abstract

A refrigeration cycle device with a main circuit, a bypass circuit and a supercooling heat exchanger further includes: a controller to control an opening degree of the bypass expansion valve; a first sensor to detect a temperature at the refrigerant inflow side of the evaporator; and a second sensor to detect a pressure of the non-azeotropic mixed refrigerant flowing from the evaporator, wherein the controller controls the opening degree of the bypass expansion valve using temperatures of the evaporator, that is, the temperature at the refrigerant inflow side and a saturated gas temperature of the non-azeotropic mixed refrigerant calculated from the pressure so as to adjust a flow rate of the non-azeotropic mixed refrigerant flowing into the evaporator, to eliminate the temperature difference in the evaporator for suppressing uneven frost formation on the evaporator, and thus to prevent heat exchange performance from degrading.

First claim

The invention claimed is:

1. A refrigeration cycle device with a main circuit in which a compressor, a condenser, a supercooling heat exchanger, a main expansion valve, and an evaporator are connected by refrigerant piping to circulate a non-azeotropic mixed refrigerant, and a bypass circuit branched from between the condenser and the evaporator to be connected to a refrigerant inflow side of the compressor, the bypass circuit including a bypass expansion valve to introduce the non-azeotropic mixed refrigerant from the main circuit, the supercooling heat exchanger exchanging heat between the non-azeotropic mixed refrigerant flowing through the main circuit and the non-azeotropic mixed refrigerant flowing through the bypass circuit, the refrigeration cycle device comprising:
a controller to control an opening degree of the bypass expansion valve;
a first sensor between the main expansion valve and the evaporator along a refrigerant flow direction of the main circuit such that the first sensor is configured to detect a temperature at a refrigerant inflow side of the evaporator; and
a second sensor to detect a pressure of the non-azeotropic mixed refrigerant flowing from the evaporator, wherein
the controller controls the opening degree of the bypass expansion valve using the temperature at the refrigerant inflow side of the evaporator detected by the first sensor and a saturated gas temperature of the non-azeotropic mixed refrigerant calculated from the pressure detected by the second sensor and adjusts a flow rate of the non-azeotropic mixed refrigerant flowing into the evaporator.

2. The refrigeration cycle device according to claim 1 , wherein when the saturated gas temperature is lower than the temperature at the refrigerant inflow side of the evaporator, the controller increases the opening degree of the bypass expansion valve to reduce the flow rate of the non-azeotropic mixed refrigerant into the evaporator.

3. The refrigeration cycle device according to claim 1 , wherein when the saturated gas temperature is higher than the temperature at the refrigerant inflow side of the evaporator, the controller reduces the opening degree of the bypass expansion valve to increase the flow rate of the non-azeotropic mixed refrigerant into the evaporator.

4. The refrigeration cycle device according to claim 1 , wherein when the temperature at the refrigerant inflow side or the saturated gas temperature of the evaporator is lower than a set temperature, the controller controls the opening degree of the bypass expansion valve to reduce the temperature difference between the refrigerant inflow side and a refrigerant outflow side of the evaporator.

5. The refrigeration cycle device according to claim 1 , wherein when the temperature at the refrigerant inflow side or the saturated gas temperature of the evaporator is lower than a set temperature, the controller controls the opening degree of the bypass expansion valve to reduce the temperature difference between the refrigerant inflow side and a refrigerant outflow side of the evaporator to be less than a set temperature difference.

6. The refrigeration cycle device according to claim 1 , wherein the bypass circuit is branched from between the supercooling heat exchanger and the evaporator.

7. The refrigeration cycle device according to claim 1 , wherein the bypass circuit is branched from between the supercooling heat exchanger and the main expansion valve.

8. The refrigeration cycle device according to claim 1 , wherein, in the evaporator, when the flow rate of the non-azeotropic mixed refrigerant flowing through the evaporator is a specific set value, the difference between the temperature at the refrigerant inflow side and the saturated gas temperature of the evaporator is less than a set temperature difference.

9. The refrigeration cycle device according to claim 1 , wherein the non-azeotropic mixed refrigerant contains any one of an olefin refrigerant, an ether refrigerant, a hydrocarbon refrigerant, an ethane refrigerant, a methane refrigerant, and a refrigerant with a lower gas density than difluoromethane.

10. The refrigeration cycle device according to claim 1 , wherein the controller controls the opening degree of the bypass expansion valve by comparing the temperature at the refrigerant inflow side of the evaporator detected by the first sensor with the saturated gas temperature of the non-azeotropic mixed refrigerant calculated from the pressure detected by the second sensor and adjusts the flow rate of the non-azeotropic mixed refrigerant flowing into the evaporator.

11. A refrigeration cycle device with a main circuit in which a compressor, a condenser, a supercooling heat exchanger, a main expansion valve, and an evaporator are connected by refrigerant piping to circulate a non-azeotropic mixed refrigerant, and a bypass circuit branched from between the condenser and the evaporator to be connected to a refrigerant inflow side of the compressor, the bypass circuit including a bypass expansion valve to introduce the non-azeotropic mixed refrigerant from the main circuit, the supercooling heat exchanger exchanging heat between the non-azeotropic mixed refrigerant flowing through the main circuit and the non-azeotropic mixed refrigerant flowing through the bypass circuit, the refrigeration cycle device comprising:
a controller to control an opening degree of the bypass expansion valve;
a first sensor to detect a temperature at a refrigerant inflow side of the evaporator; and
a second sensor to detect a pressure of the non-azeotropic mixed refrigerant flowing from the evaporator, wherein
the controller controls the opening degree of the bypass expansion valve using the temperature at the refrigerant inflow side of the evaporator detected by the first sensor and a saturated gas temperature of the non-azeotropic mixed refrigerant calculated from the pressure detected by the second sensor and adjusts a flow rate of the non-azeotropic mixed refrigerant flowing into the evaporator,
when the saturated gas temperature is lower than the temperature at the refrigerant inflow side of the evaporator, the controller increases the opening degree of the bypass expansion valve to reduce the flow rate of the non-azeotropic mixed refrigerant into the evaporator, and
when the saturated gas temperature is higher than the temperature at the refrigerant inflow side of the evaporator, the controller reduces the opening degree of the bypass expansion valve to increase the flow rate of the non-azeotropic mixed refrigerant into the evaporator.

12. A refrigeration cycle device with a main circuit in which a compressor, a condenser, a supercooling heat exchanger, a main expansion valve, and an evaporator are connected by refrigerant piping to circulate a non-azeotropic mixed refrigerant, and a bypass circuit branched from between the condenser and the evaporator to be connected to a refrigerant inflow side of the compressor, the bypass circuit including a bypass expansion valve to introduce the non-azeotropic mixed refrigerant from the main circuit, the supercooling heat exchanger exchanging heat between the non-azeotropic mixed refrigerant flowing through the main circuit and the non-azeotropic mixed refrigerant flowing through the bypass circuit, the refrigeration cycle device comprising:
a controller to control an opening degree of the bypass expansion valve;
a first sensor to detect a temperature at a refrigerant inflow side of the evaporator; and
a second sensor to detect a pressure of the non-azeotropic mixed refrigerant flowing from the evaporator, wherein
the controller controls the opening degree of the bypass expansion valve using the temperature at t

Assignees

• Mitsubishi Electric Corp

Inventors

• Mizuno Yuki
• Ikeda Soshi
• Miyawaki Kosuke
• Nishio Jun
• Motomura Yuji
• Washiyama Hiroki

Classifications

• F25B2700/21174

  of the refrigerant at the inlet of the evaporator · CPC title

• F25B47/006

  for preventing frost · CPC title

• F25B9/002

  characterised by the refrigerant · CPC title

• F25B41/31

  Expansion valves · CPC title

• F25B2500/19

  Calculation of parameters · CPC title