Air-conditioning apparatus

Patent metadata

Field	Value
Publication number	US-9857113-B2
Application number	US-201114114788-A
Country	US
Kind code	B2
Filing date	Jun 16, 2011
Priority date	Jun 16, 2011
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

A computing device calculates a quality of a refrigerant flowing out of a second expansion device on the basis of an inlet liquid enthalpy calculated on the basis of a temperature of the refrigerant flowing into the second expansion device and a saturated gas enthalpy and a saturated liquid enthalpy calculated on the basis of a temperature of the refrigerant flowing out of the second expansion device or a pressure of the refrigerant sucked into a compressor; calculates a liquid-phase concentration and a gas-phase concentration of the refrigerant flowing out of the second expansion device on the basis of the temperature of the refrigerant flowing out of the second expansion device and the pressure of the refrigerant sucked into the compressor; and calculates a composition of the refrigerant circulating in a refrigeration cycle on the basis of the calculated quality, liquid-phase concentration, and gas-phase concentration.

First claim

The invention claimed is:

1. An air-conditioning apparatus including a compressor, a first heat exchanger, an expansion device, and a second heat exchanger that are connected by a refrigerant pipe to form a refrigeration cycle, the air-conditioning apparatus using a non-azeotropic refrigerant mixture as a refrigerant for the refrigeration cycle, the air-conditioning apparatus comprising:
a bypass connected to bypass the compressor;
a bypass heat exchanger provided in the bypass and configured to cool the refrigerant flowing from the compressor into the bypass;
a second expansion device provided in the bypass and configured to reduce a pressure of the refrigerant cooled by the bypass heat exchanger;
refrigerant state detecting devices configured to detect a temperature of the refrigerant flowing into the second expansion device within ±1 ° C., a temperature of the refrigerant flowing out of the second expansion device within ±0.5 ° C., and a pressure of the refrigerant sucked into the compressor within ±0.01 MPa; and
a computing device configured to calculate a composition of the refrigerant circulating in the refrigeration cycle on the basis of each of the detection results of the refrigerant state detecting devices, the computing device is configured to
read each of detection results from an inlet temperature sensor, an outlet temperature sensor, and an outlet pressure sensor,
tentatively set a circulating refrigerant composition value as a set value,
output a physical property value from a physical property table corresponding to the set value,
calculate an inlet liquid enthalpy (Hin) of the refrigerant flowing into the second expansion device from the detection results of an inlet temperature sensor and from the physical property table,
calculate a saturated liquid enthalpy (Hls) and a saturated gas enthalpy (Hgs) of a refrigerant flowing out of the second expansion device from the detection results of an outlet temperature sensor and from the the physical property table,
calculate a Quality Xr from the inlet liquid enthalpy (Hin), the saturated liquid enthalpy (Hls), and the saturated gas enthalpy (Hgs), the Quality Xr is calculated by
dividing a first difference between the inlet liquid enthalpy (Hin) and the saturated liquid enthalpy (Hls) by a second difference between the saturated gas enthalpy (Hgs) and the saturated liquid enthalpy (Hls),

calculate a first concentration (XR32) of a liquid refrigerant flowing out of the second expansion device and a second concentration (YR32) of a gas refrigerant flowing out of the second expansion device from each of the detection results of the outlet temperature sensor, the outlet pressure sensor, and the physical property table,
calculate a Refrigerant Composition α from Quality Xr, XR32, YR32 by the following formula:
Refrigerant Composition α=(1 −Xr )* XR 32 +Xr*YR 32,

output the Refrigerant Composition α, without repeatedly calculating the inlet liquid enthalpy (Hin), the saturated liquid enthalpy (Hls), the saturated gas enthalpy (Hgs), the Quality Xr, the first concentration (XR32), the second concentration (YR32) and the Refrigerant Composition α; and
control at least one of the expansion device, the second expansion device, the compressor, the first heat exchanger, and the second heat exchanger in accordance with the Refrigerant Composition α calculated by the computing device.

2. The air-conditioning apparatus of claim 1 , further comprising:
an outdoor unit including the compressor, a first refrigerant flow switching device, and the first heat exchanger;
a heat medium relay unit including the second heat exchanger, a plurality of expansion devices, and a plurality of second refrigerant flow switching devices; and
at least one indoor unit including a use-side heat exchanger,
wherein the compressor, the first refrigerant flow switching device, the first heat exchanger, the second heat exchanger, the plurality of expansion devices, and the second refrigerant flow switching devices are connected by the refrigerant pipe to form the refrigeration cycle; and
the second heat exchanger and the use-side heat exchanger are connected by a heat medium pipe to form a heat medium circuit in which a heat medium different from the refrigerant circulates.

3. The air-conditioning apparatus of claim 1 , wherein the computing device sets the composition of the refrigerant in advance, and calculates the inlet liquid enthalpy on the basis of the set composition of the refrigerant and the temperature of the refrigerant flowing into the second expansion device.

4. The air-conditioning apparatus of claim 1 , wherein the bypass includes an opening and closing valve.

5. The air-conditioning apparatus of claim 1 , wherein a refrigerant mixture of R32 and HFO1234yf or a refrigerant mixture of R32and HFO1234ze is used as the non-azeotropic refrigerant mixture.

6. A computer-implemented method for controlling an air-conditioning apparatus, comprising:
reading each of detection results from an inlet temperature sensor, an outlet temperature sensor, and an outlet pressure sensor;
tentatively setting a circulating refrigerant composition value as a set value;
outputting a physical property value from a physical property table corresponding to the set value;
calculating an inlet liquid enthalpy (Hin) of the refrigerant flowing into a second expansion device from the detection results of an inlet temperature sensor and from the physical property table;
calculating a saturated liquid enthalpy (Hls) and a saturated gas enthalpy (Hgs) of a refrigerant flowing out of the second expansion device from the detection results of an outlet temperature sensor and from the physical property table;
calculating a Quality Xr from the inlet liquid enthalpy (Hin), the saturated liquid enthalpy (Hls), and the saturated gas enthalpy (Hgs), the Quality Xr is calculated by
dividing a first difference between the inlet liquid enthalpy (Hin) and the saturated liquid enthalpy (Hls) by a second difference between the saturated gas enthalpy (Hgs) and the saturated liquid enthalpy (Hls);

calculating a first concentration (XR32) of a liquid refrigerant flowing out of the second expansion device and a second concentration (YR32) of a gas refrigerant flowing out of the second expansion device from each of the detection results of the outlet temperature sensor, the outlet pressure sensor, and the physical property table;
calculating a Refrigerant Composition α from Quality Xr, XR32, YR32 by the following formula:
Refrigerant Composition α=(1 −Xr )* XR 32 +Xr*YR 32;

outputting the Refrigerant Composition α, without repeatedly calculating the inlet liquid enthalpy (Hin), the saturated liquid enthalpy (Hls), the saturated gas enthalpy (Hgs), the Quality Xr, the first concentration (XR32), the second concentration (YR32) and the Refrigerant Composition α; and
controlling at least one of a first expansion device, the second expansion device, a compressor, a first heat exchanger, and a second heat exchanger in accordance with the Refrigerant Composition α that is calculated.

7. An air-conditioning apparatus including a compressor, a first heat exchanger, an expansion device, and a second heat exchanger that are connected by a refrigerant pipe to form a refrigeration cycle, the air-conditioning apparatus using a non-azeotropic refrigerant mixture as a refrigerant for the refrigeration cycle, the air-conditioning apparatus comprising:
a bypass connected to bypass the compressor;
a bypass heat exchanger provided in the bypass and configured to cool the refrigerant flowing from the compressor into the bypass;
a second expansion device provided in the bypass and configured to reduce a pressure of the refrigerant cooled by the bypass heat exchanger;

Assignees

• Morimoto Hiroyuki
• Yamashita Koji
• Sumida Yoshihiro
• Shimazu yusuke
• Mitsubishi Electric Corp

Inventors

• Morimoto Hiroyuki
• Yamashita Koji
• Sumida Yoshihiro
• Shimazu yusuke

Classifications

• F25B2400/121

  using R1234 · CPC title

• F25B13/00

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

• F25B9/006 Primary

  the refrigerant containing more than one component (F25B9/004 takes precedence) · CPC title

• F25B2600/21

  Refrigerant outlet evaporator temperature · CPC title

• F25B2313/0231

  with simultaneous cooling and heating · CPC title