Air conditioner and method for controlling the same

Patent metadata

Field	Value
Publication number	US-2018347878-A1
Application number	US-201815982517-A
Country	US
Kind code	A1
Filing date	May 17, 2018
Priority date	May 31, 2017
Publication date	Dec 6, 2018
Grant date	—

Abstract

An air conditioner and a method for controlling the same are disclosed. The air conditioner implements a multistage expansion scheme by implementing serial connection between electronic expansion valves including in the R410A refrigerant-based air conditioner, and thus guarantees an optimum compression ratio in all cooling/heating load regions. Therefore, although cycle characteristics are changed by changing R410A refrigerant to R32 refrigerant, the air conditioner optimizes the cycle simply by controlling a degree of opening of electronic expansion valves, respectively. As described above, since the cycle optimization is implemented using the multistage expansion scheme in which legacy electronic expansion valves are coupled in series, the design modification is minimized without design modification of requisite constituent elements such as a heat exchanger, system implementation is facilitated, resulting in high efficiency in cost and productivity. Cooling/heating performance improvement and reliability guarantee are achieved under all load conditions, resulting in increased system efficiency.

First claim

What is claimed is:

1 . An air conditioner comprising:
a compressor configured to compress a refrigerant; a flow passage switching valve configured to switch flow of the refrigerant according to at least one of a cooling mode and a heating mode, respectively; and a multistage expansion device configured to decompress the refrigerant, wherein the compressor is a rotary compressor using the refrigerant as an operating fluid, and
the multistage expansion device includes a first expansion valve to decompress a pressure of the refrigerant when the refrigerant is a high-pressure refrigerant and a second expansion valve to decompress the pressure of the refrigerant when the refrigerant is a medium-pressure refrigerant.

2 . The air conditioner according to claim 1 , wherein the refrigerant is R32 refrigerant, and
the first expansion valve and the second expansion valve are connected in series to implement a 2-stage expansion scheme, and adjust a flow rate and a pressure of the R32 refrigerant through change of a degree of opening of the first expansion value and a degree of opening of the second expansion value, respectively.

3 . The air conditioner according to claim 2 , wherein the compressor is a revolutions per minute (RPM) variable type compressor having changeable capacity.

4 . The air conditioner according to claim 3 , further comprising:
a controller configured to control the degree of opening of the first expansion valve and the degree of opening of the second expansion valve, respectively, so as to acquire an optimum compression ratio in all load regions of the cooling mode and the heating mode, respectively.

5 . The air conditioner according to claim 4 , further comprising:
an outdoor-temperature detector configured to detect an outdoor temperature; and a revolutions per minute (RPM) detector configured to detect revolutions per minute (RPM) of the compressor, wherein the controller selects an initial opening degree of each of the first expansion valve and the second expansion valve in response to the outdoor temperature detected by the outdoor-temperature detector and a compressor RPM detected by the RPM detector.

6 . The air conditioner according to claim 5 , further comprising:
an indoor-temperature detector configured to detect an indoor temperature, wherein the controller selects the initial opening degree of each of the first expansion valve and the second expansion valve in response to the indoor temperature detected by the indoor-temperature detector, the outdoor temperature detected by the outdoor-temperature detector, and the compressor RPM detected by the RPM detector.

7 . The air conditioner according to claim 5 , further comprising:
a discharge temperature detector configured to detect a refrigerant temperature at an outlet of the compressor, wherein the controller calculates a target opening degree of the first expansion valve and the second expansion valve, respectively, in response to a compressor discharge temperature detected by the discharge temperature detector and the compressor RPM detected by the RPM detector.

8 . The air conditioner according to claim 7 , wherein the controller controls the target opening degree of the first expansion valve and the second expansion valve, respectively, by detecting the compressor discharge temperature and the compressor RPM at intervals of a predetermined time.

9 . The air conditioner according to claim 7 , further comprising:
a detector configured to detect a current opening degree of the first expansion valve and the second expansion valve, respectively, wherein the controller periodically traces and controls the target opening degree of the first expansion valve and the second expansion valve, respectively, in response to the compressor discharge temperature, the compressor RPM, and the current opening degrees of the first expansion valve and the second expansion valve.

10 . The air conditioner according to claim 5 , further comprising:
an indoor-temperature detector configured to detect the indoor temperature; and an outdoor-temperature detector configured to detect the outdoor temperature, wherein the controller predicts a cooling/heating load in response to the indoor temperature detected by the indoor-temperature detector and the outdoor temperature detected by the outdoor-temperature detector, and controls the degree of opening of the first expansion valve.

11 . The air conditioner according to claim 10 , further comprising:
a detector configured to detect a current opening degree of the first expansion valve and the second expansion valve, respectively, wherein the controller periodically traces and controls the target opening degree of the first expansion valve in response to the indoor temperature, the outdoor temperature, and the current opening degree of the first expansion valve.

12 . The air conditioner according to claim 11 , further comprising:
a discharge temperature detector configured to detect a refrigerant temperature at an outlet of the compressor, wherein the controller periodically traces and controls a target opening degree of the second expansion valve in response to a compressor discharge temperature detected by the discharge temperature detector, the compressor RPM, and the current opening degree of the second expansion valve.

13 . A method for controlling an air conditioner which includes a compressor to compress refrigerant, a first expansion valve and a second expansion valve to decompress the refrigerant using a 2-stage expansion scheme, wherein the compressor is a rotary compressor using R32 refrigerant as an operating fluid, the method comprising:
detecting an outdoor temperature, a revolutions per minute (RPM) of the compressor, and a refrigerant discharge temperature of the compressor; selecting an initial opening degree of the first expansion valve and the second expansion valve, respectively, in response to the detected outdoor temperature and the compressor RPM; calculating a target opening degree of the first expansion valve and the second expansion valve, respectively, in response to the compressor discharge temperature and the compressor RPM; and controlling a degree of opening of the first expansion valve and a degree of opening of the second expansion valve according to the respective calculated target opening degree of the first expansion valve and the second expansion valve.

14 . The method according to claim 13 , wherein the controlling of the degree of opening of the first expansion valve and the degree of opening of the second expansion valve includes:
controlling the target opening degree of the first expansion valve and the second expansion valve, respectively, by detecting the compressor discharge temperature and the compressor RPM at intervals of a predetermined time.

15 . The method according to claim 14 , further comprising:
detecting a current opening degree of the first expansion valve and the second expansion valve, respectively, wherein the controlling of the degree of opening of the first expansion valve and the degree of opening of second expansion valve includes:
periodically tracing and controlling the target opening degree of the first expansion valve and the second expansion valve, respectively, in response to the compressor discharge temperature, the compressor RPM, and the respective current opening degrees of the first expansion valve and the second expansion valve.

16 . The method according to claim 15 , further comprising:
detecting the indoor temperature; and predicting a cooling/heatin

Assignees

• Samsung Electronics Co Ltd

Inventors

• Son Kil Soo
• Kim Seok Kyun
• Baek Jong-Yeop
• Ahn Byoung-Ok
• Cho Dong-Ho
• Kim Hyun Kook
• Shin Hyo-Jun
• Yoo Sang Ho
• Jun Hong Seok

Classifications

• F25B2313/005

  Outdoor unit expansion valves · CPC title

• F25B1/04

  with compressor of rotary type ({F25B1/005,} F25B1/10 take precedence) · CPC title

• F25B2600/0253

  with variable speed · CPC title

• F25B2700/171

  of the compressor · CPC title

• F25B2600/2513

  Expansion valves · CPC title