Air conditioner

Abstract

In an air conditioner, a control section controls at least the indoor expansion valve. The indoor expansion valve has a degree of opening that is controllable. The control section has a condensate formation suppressing control mode and a normal heating control mode. The condensate formation suppressing control mode is performed in a case where a predetermined condensate formation condition is satisfied. The predetermined condensate formation condition relates to generation of condensate formation on the connecting section. The normal heating control mode is performed in cases other than the case where the predetermined condensate formation condition is satisfied. The control section increases the opening degree of the indoor expansion valve when the condensate formation suppressing control mode is performed compared to a case when the normal heating control mode is performed.

1 . An air conditioner comprising:
 a refrigerant circuit configured to perform at least a heating operation, the refrigerant circuit including
 an indoor unit having an indoor expansion valve and an indoor heat exchanger arranged therein, 
 an outdoor unit having an outdoor expansion valve, an outdoor heat exchanger, and a compressor arranged therein, and 
 a connecting section connecting the indoor expansion valve and the outdoor expansion valve; and 
   a control section controlling at least the indoor expansion valve, the indoor expansion valve having a degree of opening that is controllable,   the control section having
 a condensate formation suppressing control mode, which is performed in a case where a predetermined condensate formation condition is satisfied, the predetermined condensate formation condition relating to generation of condensate formation on the connecting section, and 
 a normal heating control mode which is performed in cases other than the case where the predetermined condensate formation condition is satisfied, and 
   the control section increasing the opening degree of the indoor expansion valve when the condensate formation suppressing control mode is performed compared to a case when the normal heating control mode is performed.   
     
     
         2 . The air conditioner according to  claim 1 , further comprising:
 a first sensor arranged and configured to ascertain temperature or pressure of refrigerant flowing between the indoor expansion valve and the outdoor expansion valve; and   a second sensor arranged and configured to ascertain temperature of the surroundings of the connection section,   the control section determining whether or not the predetermined condensate formation condition is satisfied based on information ascertained from the first sensor and the second sensor.   
     
     
         3 . The air conditioner according to  claim 2 , wherein
 the connecting section has a portion extending outdoors, and   the second sensor is an outdoor air temperature sensor.   
     
     
         4 . The air conditioner according to  claim 2 , wherein
 the control section controls the opening degree of the indoor expansion valve such that a degree of subcooling of refrigerant at an outlet of the indoor heat exchanger becomes a predetermined normal subcooling target value in the normal heating control mode.   
     
     
         5 . The air conditioner according to  claim 3 , wherein
 the control section controls the opening degree of the indoor expansion valve such that a degree of subcooling of refrigerant at an outlet of the indoor heat exchanger becomes a predetermined normal subcooling target value in the normal heating control mode.   
     
     
         6 . The air conditioner according to  claim 4 , wherein
 the control section controls the opening degree of the indoor expansion valve such that the degree of subcooling becomes a condensate formation suppressing subcooling target value, which is a subcooling target value smaller than the normal subcooling target value in the normal heating control mode, in the condensate formation suppressing control mode, and   the control section sets the condensate formation suppressing subcooling target value to be smaller as the temperature of refrigerant which is ascertained from the first sensor is lower.   
     
     
         7 . The air conditioner according to  claim 5 , wherein
 the control section controls the opening degree of the indoor expansion valve such that the degree of subcooling becomes a condensate formation suppressing subcooling target value in the condensate formation suppressing control mode,   the condensate formation suppressing subcooling target value is a subcooling target value smaller than the predetermined normal subcooling target value in the normal heating control mode, and   the control section sets the condensate formation suppressing subcooling target value to be smaller as the temperature of refrigerant ascertained from the first sensor decreases.   
     
     
         8 . The air conditioner according to  claim 3 , wherein
 the control section fully opens the indoor expansion valve in a case when the temperature of refrigerant ascertained from the first sensor is lower than a slop reference temperature when performing the condensate formation suppressing control mode, and   the stop reference temperature is obtained by adding a reference predetermined value to the outdoor air temperature ascertained from the second sensor.   
     
     
         9 . The air conditioner according to  claim 8 , wherein
 the control section starts the normal heating control mode in a case when the temperature of refrigerant ascertained from the first sensor is higher than a return reference temperature obtained by adding a return predetermined value to the outdoor air temperature ascertained from the second sensor, and   the return predetermined value is larger than the reference predetermined value.   
     
     
         10 . The air conditioner according to  claim 7 , wherein
 the control section fully opens the indoor expansion valve in a case when the temperature of refrigerant ascertained from the first sensor is lower than a stop reference temperature when performing the condensate formation suppressing control mode, and   the stop reference temperature is obtained by adding a reference predetermined value to the outdoor air temperature ascertained from the second sensor.   
     
     
         11 . The air conditioner according to  claim 10 , wherein
 the control section starts the normal heating control mode in a case when the temperature of refrigerant ascertained from the first sensor is higher than a return reference temperature obtained by adding a return predetermined value to the outdoor air temperature ascertained from the second sensor, and   the return predetermined value is larger than the reference predetermined value.   
     
     
         12 . The air conditioner according to  claim 2 , wherein
 the control section controls the opening degree of the outdoor expansion valve such that a degree of superheat of refrigerant which is suctioned into the compressor becomes a predetermined normal superheat target value while controlling the opening degree of the indoor expansion valve such that a degree of subcooling of refrigerant at an outlet of the indoor heat exchanger becomes a predetermined nominal subcooling target value in the normal heating control mode.   
     
     
         13 . The air conditioner according to  claim 3 , wherein
 the control section controls the opening degree of the outdoor expansion valve such that a degree of superheat of refrigerant which is suctioned into the compressor becomes a predetermined normal superheat target value while controlling the opening degree of the indoor expansion valve such that a degree of subcooling of refrigerant at an outlet of the indoor heat exchanger becomes a predetermined nominal subcooling target value in the normal heating control mode.   
     
     
         14 . The air conditioner according to  claim 12 , wherein
 the control section controls the opening degree of the indoor expansion valve such that the degree of subcooling becomes a condensate formation suppressing subcooling target value in the condensate formation suppressing control mode,   the condensate formation suppressing subcooling target value is a subcooling target value smaller than the predetermined normal subcooling target value in the normal healing control mode, and   the control section sets the condensate formation suppressing subcooling target value to be smaller as the temperature of refrigerant ascertained from the first sensor decreases.   
     
     
         15 . The air conditioner according to  claim 13 , wherein
 the control section controls the opening degree of the indoor expansion valve such that the degree of subcooling becomes a condensate formation suppressing subcooling target value in the condensate formation suppressing control mode,   the condensate formation suppressing subcooling target value is a subcooling target value smaller than the predetermined normal subcooling target value in the normal heating control mode, and   the control section sets the condensate formation suppressing subcooling target value to be smaller as the temperature of refrigerant ascertained from the first sensor decreases.   
     
     
         16 . The air conditioner according to  claim 15 , wherein
 the control section fully opens the indoor expansion valve in a case when the temperature of refrigerant ascertained from the first sensor is lower than a stop reference temperature when performing the condensate formation suppressing control mode, and   the stop reference temperature is obtained by adding a reference predetermined value to the outdoor air temperature ascertained from the second sensor.   
     
     
         17 . The air conditioner according to  claim 16 , wherein
 the control section starts the normal heating control mode in a case when the temperature of refrigerant ascertained from the first sensor is higher than a return reference temperature which is obtained by adding a return predetermined value to the outdoor air temperature ascertained from the second sensor, and   the return predetermined value is larger than the reference predetermined value.