Air-conditioning apparatus

Patent metadata

Field	Value
Publication number	US-2016116202-A1
Application number	US-201314894151-A
Country	US
Kind code	A1
Filing date	May 31, 2013
Priority date	May 31, 2013
Publication date	Apr 28, 2016
Grant date	—

Abstract

An air-conditioning apparatus includes: a compressor allowing refrigerant injection thereto and compress and discharge the refrigerant at a high temperature; an indoor heat exchanger exchanging heat between air and refrigerant; a first flow rate control device adjusting and controlling a flow rate of refrigerant; and a plurality of outdoor heat exchangers being in parallel to exchange heat between outside air and refrigerant, a first defrosting pipe allowing a branched part of the refrigerant discharged from the compressor to pass and flow into the outdoor heat exchanger to be defrosted; a reducing device adjusting a pressure of refrigerant passing through the first defrosting pipe to a medium pressure; a second defrosting pipe from which the refrigerant having passed through the outdoor heat exchanger to be defrosted is injected into the compressor; and a reducing device adjusting a pressure of refrigerant passing through the second defrosting pipe to an injection pressure.

First claim

1 . An air-conditioning apparatus comprising:
a compressor to allow refrigerant to be injected into a portion thereof located intermediate of a compression stroke, suck the refrigerant having a low pressure, compress the refrigerant, and discharge the refrigerant having a high temperature; an indoor heat exchanger to exchange heat between air to be conditioned and the refrigerant; a first flow rate control device to adjust and control a flow rate of the refrigerant passing through the indoor heat exchanger; a plurality of outdoor heat exchangers connected in parallel to exchange heat between outdoor air and the refrigerant, the compressor, the indoor heat exchanger, the first flow rate control device, and the plurality of outdoor heat exchangers being connected by pipes to form a main refrigerant circuit in which the refrigerant circulates; a first defrosting pipe to allow a branched part of the refrigerant discharged from the compressor to pass therethrough and flow into at least one of the outdoor heat exchangers to be defrosted; a first pressure adjustment device to adjust a pressure of the refrigerant passing through the first defrosting pipe to a medium pressure higher than the low pressure and lower than the high pressure; a second defrosting pipe to allow the refrigerant that has passed through the at least one of the outdoor heat exchangers to be defrosted to pass therethrough to be injected into the compressor; and a second pressure adjustment device to adjust a pressure of the refrigerant passing through the second defrosting pipe to an injection pressure.

2 . The air-conditioning apparatus of claim 1 , being configured to perform defrosting and heating by causing at least one of the outdoor heat exchangers other than the at least one of the outdoor heat exchangers to be defrosted to serve as an evaporator.

3 . The air-conditioning apparatus of claim 2 , further comprising a third pressure adjustment device to adjust a pressure of the refrigerant that has flowed out of the at least one of the outdoor heat exchangers to be defrosted and cause the refrigerant to flow into upstream of the outdoor heat exchanger, serving as the evaporator, in the main refrigerant circuit.

4 . The air-conditioning apparatus of claim 3 , further comprising a refrigerant-refrigerant heat exchanger to exchange heat between the refrigerant flowing in the main refrigerant circuit to flow into the at least one of the outdoor heat exchangers serving as the evaporator and the refrigerant flowing in the second defrosting pipe.

5 . The air-conditioning apparatus of claim 1 , further comprising a fourth pressure adjustment device to adjust a pressure of the refrigerant flowing in the main refrigerant circuit and cause the refrigerant to flow into the second defrosting pipe.

6 . The air-conditioning apparatus of claim 1 , wherein
the outdoor heat exchanger includes
a plurality of heat transfer tubes to allow the refrigerant to pass therethrough, the plurality of heat transfer tubes arranged in a plurality of levels extending perpendicularly to direction of passage of air and in a plurality of columns extending in parallel with the direction of passage of air, and
a plurality of fins spaced from one another so that air passes therethrough in the direction of passage of air,
a pipe connected to the heat transfer tubes in a column upstream in the direction of passage of air is connected to the first defrosting pipe, and a pipe connected to the heat transfer tubes in a column downstream in the direction of passage of air is connected to the second defrosting pipe.

7 . The air-conditioning apparatus of claim 3 , wherein the third pressure adjustment device is configured to control a pressure of the refrigerant flowing out of at least one of the outdoor heat exchangers to be defrosted.

8 . The air-conditioning apparatus of claim 7 , wherein the third pressure adjustment device is configured to control the pressure of the refrigerant flowing out of the at least one of the outdoor heat exchangers to be defrosted to have a pressure corresponding to a saturation temperature of higher than 0 degrees C. and lower than or equal to 10 degrees C.

9 . The air-conditioning apparatus of claim 1 , being configured to control a discharge temperature or a discharge superheat of the refrigerant discharged from the compressor by adjustment of pressure by the second pressure adjustment device.

10 . The air-conditioning apparatus of claim 1 , further comprising an outdoor-air temperature detector to detect an outdoor-air temperature of air outside a space to be air-conditioned, wherein
the first pressure adjustment device is configured to perform a flow rate control based on the outdoor-air temperature.

11 . The air-conditioning apparatus of claim 1 , further comprising an outdoor-air temperature detector to detect an outdoor-air temperature of air outside a space to be air-conditioned, the air-conditioning apparatus being configured to change a criterion for determining whether to start a defrosting operation, based on the outdoor-air temperature.

12 . The air-conditioning apparatus of claim 1 , further comprising an outdoor-air temperature detector to detect an outdoor-air temperature of air outside a space to be air-conditioned, the air-conditioning apparatus being configured to select, based on the outdoor-air temperature, from
a heating-and-defrosting operation mode in which the at least one of the outdoor heat exchangers to be defrosted is selected and defrosted and another one of the outdoor heat exchangers serves as an evaporator so as to continue heating, and a heating-stop defrosting operation mode in which all the outdoor heat exchangers are defrosted.

13 . The air-conditioning apparatus of claim 1 , further comprising
an outdoor-air temperature detector to detect an outdoor-air temperature of air outside a space to be air-conditioned, and an outdoor fan to blow the outdoor air to the plurality of outdoor heat exchangers, the air-conditioning apparatus being configured to change, based on the outdoor-air temperature, output power of the outdoor fan in defrosting the at least one of the outdoor heat exchangers to be defrosted.

14 . The air-conditioning apparatus of claim 1 , being configured to defrost each of the plurality of outdoor heat exchangers at least once in the defrosting operation mode.

Assignees

• Mitsubishi Electric Corp

Inventors

• Takenaka Naofumi
• Wakamoto Shinichi
• Watanabe Kazuya
• Yamashita Koji
• Hatomura Takeshi

Classifications

• F25B2313/0253

  in parallel arrangements · CPC title

• F25B47/022

  hot gas defrosting · CPC title

• F25B2313/0233

  in parallel arrangements · CPC title

• F25B2313/006

  two pipes connecting the outdoor side to the indoor side with multiple indoor units · CPC title

• F25B2313/02741

  using one four-way valve · CPC title