Air conditioning apparatus

Abstract

An air conditioning apparatus includes a compression element, a refrigerant cooler, an expansion element, a refrigerant heater, a magnetic field generator, a generated heat temperature sensor and a control part. The magnetic field generator generates a magnetic field in order to induction-heat a refrigerant tube circulating refrigerant and/or a member in thermal contact with refrigerant flowing through the refrigerant tube. The generated heat temperature sensor senses temperature of a portion that generates heat due to the induction heating. The control part performs superheating protection control in order to increase an opening degree of the expansion mechanism when the temperature sensed by the generated heat temperature sensor reaches or exceeds a predetermined generated heat temperature, or when a rate of increase of the temperature sensed by the generated heat temperature sensor reaches or exceeds a predetermined rate of increase.

1 . An air conditioning apparatus comprising:
 a compression element;   a refrigerant cooler;   an expansion element;   a refrigerant heater;   a magnetic field generator arranged to generate a magnetic field in order to induction-heat
 a refrigerant tube arranged to circulate refrigerant to the compression element, the refrigerant cooler, the expansion element, and the refrigerant heater, and/or 
 a member in thermal contact with refrigerant flowing through the refrigerant tube; 
   a generated heat temperature sensor arranged and configured to sense temperature of a portion that generates heat due to the induction heating by the magnetic field generator; and   a control part configured to perform superheating protection control in order to increase an opening degree of the expansion mechanism
 when the temperature sensed by the generated heat temperature sensor reaches or exceeds a predetermined generated heat temperature, or 
 when a rate of increase of the temperature sensed by the generated heat temperature sensor reaches or exceeds a predetermined rate of increase. 
   
     
     
         2 . The air conditioning apparatus according to  claim 1 , wherein
 the magnetic field generator is arranged to generate a magnetic field in order to induction-heat an intake refrigerant tube within the refrigerant tube in an intake side of the compression element and/or a member in thermal contact with refrigerant flowing through the intake refrigerant tube.   
     
     
         3 . The air conditioning apparatus according to  claim 1 , wherein
 the control part is further configured
 to perform startup control in which the magnetic field generator is caused to generate a magnetic field so that the temperature of the portion where heat is generated due to the induction heating by the magnetic field generator reaches a predetermined startup target temperature while driving of the compression element is initiated from a stopped state of the compression element, and 
 to perform post-startup control after the startup control has ended; and 
   when the superheating protection control is performed at the same time the post-startup control is being performed, the control part is further configured to increase the opening degree of the expansion mechanism when the temperature sensed by the generated heat temperature sensor reaches or exceeds a post-startup predetermined generated heat temperature, which is a temperature equal to or greater than the predetermined startup target temperature.   
     
     
         4 . The air conditioning apparatus according to  claim 3 , wherein
 when the superheating protection control is performed at the same time the startup control is being performed, the control part is further configured to increase the opening degree of the expansion mechanism when the rate of increase of the temperature sensed by the generated heat temperature sensor at a time when the predetermined startup target temperature is reached reaches or exceeds the predetermined rate of increase.   
     
     
         5 . The air conditioning apparatus according to  claim 4 , wherein
 when the predetermined rate of increase is determined to have been reached or exceeded, the control part is further configured to increase the opening degree of the expansion mechanism only when rotational speed of the compression mechanism reaches or exceeds a predetermined rotational speed.   
     
     
         6 . The air conditioning apparatus according to  claim 3 , further comprising
 a cooler-side-refrigerant-state-perceiving part arranged and configured to perceive a state of refrigerant passing through from the refrigerant cooler to the expansion mechanism,   when the startup control has ended, the control part being further configured to initiate subcooling-degree-fixing control in order to control the opening degree of the expansion mechanism so that a degree of subcooling of the refrigerant perceived using a value perceived by the cooler-side-refrigerant-state-perceiving part is kept fixed at a predetermined target degree of subcooling, and   when the superheating protection control is performed at the same time the subcooling-degree-fixing control is being performed, the control part being further configured to further increase the opening degree of the expansion mechanism beyond the opening degree controlled by the subcooling-degree-fixing control when the temperature sensed by the generated heat temperature sensor reaches or exceeds a predetermined subcooling-degree-fixing control generated heat temperature, which is a temperature equal to or greater than the predetermined startup target temperature.   
     
     
         7 . The air conditioning apparatus according to  claim 2 , wherein
 the control part is further configured
 to perform startup control in which the magnetic field generator is caused to generate a magnetic field so that the temperature of the portion where heat is generated due to the induction heating by the magnetic field generator reaches a predetermined startup target temperature while driving of the compression element is initiated from a stopped state of the compression element, and 
 to perform post-startup control after the startup control has ended; and 
   when the superheating protection control is performed at the same time the post-startup control is being performed, the control part is further configured to increase the opening degree of the expansion mechanism when the temperature sensed by the generated heat temperature sensor reaches or exceeds a post-startup predetermined generated heat temperature, which is a temperature equal to or greater than the predetermined startup target temperature.   
     
     
         8 . The air conditioning apparatus according to  claim 7 , further comprising
 a cooler-side-refrigerant-state-perceiving part arranged and configured to perceive a state of refrigerant passing through from the refrigerant cooler to the expansion mechanism,   when the startup control has ended, the control part being further configured to initiate subcooling-degree-fixing control in order to control the opening degree of the expansion mechanism so that a degree of subcooling of the refrigerant perceived using a value perceived by the cooler-side-refrigerant-state-perceiving part is kept fixed at a predetermined target degree of subcooling, and   when the superheating protection control is performed at the same time the subcooling-degree-fixing control is being performed, the control part being further configured to further increase the opening degree of the expansion mechanism beyond the opening degree controlled by the subcooling-degree-fixing control when the temperature sensed by the generated heat temperature sensor reaches or exceeds a predetermined subcooling-degree-fixing control generated heat temperature, which is a temperature equal to or greater than the predetermined startup target temperature.   
     
     
         9 . The air conditioning apparatus according to  claim 4 , further comprising
 a cooler-side-refrigerant-state-perceiving part arranged and configured to perceive a state of refrigerant passing through from the refrigerant cooler to the expansion mechanism,   when the startup control has ended, the control part being further configured to initiate subcooling-degree-fixing control in order to control the opening degree of the expansion mechanism so that a degree of subcooling of the refrigerant perceived using a value perceived by the cooler-side-refrigerant-state-perceiving part is kept fixed at a predetermined target degree of subcooling, and   when the superheating protection control is performed at the same time the subcooling-degree-fixing control is being performed, the control part being further configured to further increase the opening degree of the expansion mechanism beyond the opening degree controlled by the subcooling-degree-fixing control when the temperature sensed by the generated heat temperature sensor reaches or exceeds a predetermined subcooling-degree-fixing control generated heat temperature, which is a temperature equal to or greater than the predetermined startup target temperature.   
     
     
         10 . The air conditioning apparatus according to  claim 5 , further comprising
 a cooler-side-refrigerant-state-perceiving part arranged and configured to perceive a state of refrigerant passing through from the refrigerant cooler to the expansion mechanism,   when the startup control has ended, the control part being further configured to initiate subcooling-degree-fixing control in order to control the opening degree of the expansion mechanism so that a degree of subcooling of the refrigerant perceived using a value perceived by the cooler-side-refrigerant-state-perceiving part is kept fixed at a predetermined target degree of subcooling, and   when the superheating protection control is performed at the same time the subcooling-degree-fixing control is being performed, the control part being further configured to further increase the opening degree of the expansion mechanism beyond the opening degree controlled by the subcooling-degree-fixing control when the temperature sensed by the generated heat temperature sensor reaches or exceeds a predetermined subcooling-degree-fixing control generated heat temperature, which is a temperature equal to or greater than the predetermined startup target temperature.