Air-conditioning device and method for controlling air-conditioning device

Abstract

Provided is a vehicle air-conditioning device comprising: a circulation channel that guides a refrigerant that has passed through a heating until towards an accumulator; a bypass channel that guides the refrigerant towards the accumulator without passing through the heating unit; and a control unit that controls the opening amount of an expansion valve provided on the circulation channel and an expansion valve provided on the bypass channel, wherein the control unit controls the opening amount of the expansion valve and the expansion valve so that the proportion of gas refrigerant in inflow refrigerant flowing into the accumulator is greater than the proportion of gas refrigerant in outflow refrigerant flowing out of the accumulator when the pressure of the refrigerant drawn in by a compressor is less than a predetermined pressure, and that the proportion of liquid refrigerant in the inflow refrigerant is greater than the proportion of liquid refrigerant in the outflow refrigerant when the pressure of the refrigerant drawn in by the compressor is greater than the predetermined pressure.

1 . An air conditioning device comprising:
 a compressor that compresses a refrigerant;   a heating unit that heats a heating target with the refrigerant discharged from the compressor;   an accumulator that separates a liquid component in the refrigerant sucked by the compressor;   a circulation flow path that guides the refrigerant, which has passed through the heating unit, to the accumulator;   a bypass flow path that guides the refrigerant discharged from the compressor to the accumulator without passing the refrigerant through the heating unit;   a first expansion mechanism that is disposed at the circulation flow path and that expands the refrigerant flowing out from the heating unit;   a second expansion mechanism that is disposed at the bypass flow path and that expands the refrigerant discharged from the compressor; and   a control unit that controls a first opening degree of the first expansion mechanism and a second opening degree of the second expansion mechanism,   wherein the control unit
 in a case where a pressure of the refrigerant sucked by the compressor is lower than a predetermined pressure, controls the first opening degree and the second opening degree such that a proportion of a gas refrigerant in an inflow refrigerant flowing into the accumulator, including the refrigerant expanded by the first expansion mechanism and the refrigerant expanded by the second expansion mechanism, is larger than a proportion of a gas refrigerant in an outflow refrigerant flowing out from the accumulator, and 
 in a case where the pressure of the refrigerant sucked by the compressor is higher than the predetermined pressure, controls the first opening degree and the second opening degree such that a proportion of a liquid refrigerant in the inflow refrigerant is larger than a proportion of a liquid refrigerant in the outflow refrigerant flowing out from the accumulator. 
   
     
     
         2 . The air conditioning device according to  claim 1 , further comprising:
 a switching unit that switches between a first operation mode in which the refrigerant discharged from the compressor is guided to the bypass flow path without being guided to the circulation flow path and a second operation mode in which the refrigerant discharged from the compressor is guided to both the circulation flow path and the bypass flow path,   wherein the control unit controls the switching unit such that the first operation mode is switched to the second operation mode in accordance with whether or not the pressure of the refrigerant sucked by the compressor exceeds a threshold pressure.   
     
     
         3 . The air conditioning device according to  claim 1 ,
 wherein in a case of reducing power of the compressor, the control unit controls the first opening degree and the second opening degree such that the proportion of the liquid refrigerant in the inflow refrigerant is not changed.   
     
     
         4 . The air conditioning device according to  claim 1 ,
 wherein in a case of increasing power of the compressor, the control unit controls the first opening degree and the second opening degree such that the proportion of the liquid refrigerant in the inflow refrigerant is not changed.   
     
     
         5 . The air conditioning device according to  claim 1 , further comprising:
 a heat exchanger that exchanges heat between outside air and the refrigerant;   a first flow path that guides the refrigerant, which has passed through the heating unit, to the heat exchanger;   a second flow path that guides the refrigerant, which has passed through the heat exchanger, to the accumulator;   a first on-off valve that is disposed at the first flow path; and   a second on-off valve that is disposed at the second flow path,   wherein in a case of circulating the refrigerant in the circulation flow path by setting the first on-off valve and the second on-off valve to a closed state, an amount of the refrigerant to be enclosed in a refrigerant flow path, including the circulation flow path, the bypass flow path, the first flow path, and the second flow path, is set such that the heating unit is capable of heating the heating target.   
     
     
         6 . The air conditioning device according to  claim 1 , further comprising:
 a refrigerant heating heater that heats the refrigerant flowing into the accumulator.   
     
     
         7 . The air conditioning device according to  claim 1 , further comprising:
 a heat exchanger that exchanges heat between outside air and the refrigerant;   an evaporator that evaporates the refrigerant which has passed through the heat exchanger;   a blower that guides air dehumidified by the evaporator to the heating unit;   a first flow path that guides the refrigerant, which has passed through the heating unit, to the heat exchanger; and   a second flow path that guides the refrigerant, which has passed through the heat exchanger, to the accumulator via the evaporator.   
     
     
         8 . The air conditioning device according to  claim 1 , wherein the control unit controls an opening degree of the first expansion mechanism such that the refrigerant which has passed through the heating unit becomes the liquid refrigerant. 
     
     
         9 . A method for controlling an air conditioning device,
 in which the air conditioning device includes
 a compressor that compresses a refrigerant, 
 a heating unit that heats a heating target with the refrigerant discharged from the compressor, 
 an accumulator that separates a liquid component in the refrigerant sucked by the compressor, 
 a circulation flow path that guides the refrigerant, which has passed through the heating unit, to the accumulator, 
 a bypass flow path that guides the refrigerant discharged from the compressor to the accumulator without passing the refrigerant through the heating unit, 
 a first expansion mechanism that is disposed at the circulation flow path and that expands the refrigerant flowing out from the heating unit, and 
 a second expansion mechanism that is disposed at the bypass flow path and that expands the refrigerant discharged from the compressor, the method comprising: 
   a first control step of, in a case where a pressure of the refrigerant sucked by the compressor is lower than a predetermined pressure, controlling a first opening degree of the first expansion mechanism and a second opening degree of the second expansion mechanism such that a proportion of a gas refrigerant in an inflow refrigerant flowing into the accumulator, including the refrigerant expanded by the first expansion mechanism and the refrigerant expanded by the second expansion mechanism, is larger than a proportion of a gas refrigerant in an outflow refrigerant flowing out from the accumulator; and   a second control step of, in a case where the pressure of the refrigerant sucked by the compressor is higher than the predetermined pressure, controlling the first opening degree and the second opening degree such that a proportion of a liquid refrigerant in the inflow refrigerant is larger than a proportion of a liquid refrigerant in the outflow refrigerant flowing out from the accumulator.