Air conditioning device

Abstract

In an air conditioning device ( 1 ) that includes: a PTC heater ( 55 ) in which, in a stable region (S 1 ), when the temperature of the PTC heater ( 55 ) is increased, a resistance is decreased or is substantially constant whereas, in a rise region (S 2 ), the resistance is rapidly increased when the temperature exceeds a rise temperature (T 1 ); and an air blower ( 25 ) that generates an air current which exchanges heat with the PTC heater ( 55 ), and that performs a heating operation by discharging air heated by the PTC heater ( 55 ) into the room, when the temperature within the room is within a low temperature range including a region whose temperature is lower than a set temperature, the duty ratio is set at 100%, and the PTC heater ( 55 ) is driven in the rise region (S 2 ), when the temperature within the room is within a high temperature range whose temperatures are higher than the set temperature, the PTC heater ( 55 ) is stopped, and when the temperature within the room is within an intermediate temperature range between the low temperature range and the high temperature range, the duty ratio is set at a predetermined duty ratio, and the PTC heater ( 55 ) is driven in the stable region (S 1 ).

1 . An air conditioning device comprising:
 a PTC heater in which, in a stable region, when a temperature of the PTC heater is increased, a resistance of the PTC heater is decreased or is substantially constant whereas, in a rise region, the resistance is rapidly increased when the temperature exceeds a rise temperature;   a heater control portion that controls a duty ratio of the PTC heater;   a temperature detection portion that detects a temperature within a room; and   an air blower that generates an air current which exchanges heat with the PTC heater,   wherein a heating operation is performed by discharging air heated by the PTC heater into the room,   when the temperature within the room is within a low temperature range including a region whose temperature is lower than a set temperature, the duty ratio is set at 100%, and the PTC heater is driven in the rise region,   when the temperature within the room is within a high temperature range whose temperatures are higher than the set temperature, the PTC heater is stopped, and   when the temperature within the room is within an intermediate temperature range between the low temperature range and the high temperature range, the duty ratio is set at a predetermined duty ratio, and the PTC heater is driven in the stable region.   
     
     
         2 . The air conditioning device of  claim 1 ,
 wherein the intermediate temperature range is further divided into a plurality of auxiliary temperature ranges, and, when the temperature within the room is within a high temperature-side auxiliary temperature range, the duty ratio of the PTC heater is set lower than a duty ratio at the time of a low temperature-side auxiliary temperature range.   
     
     
         3 . The air conditioning device of  claim 2 ,
 wherein, when the temperature within the room is within the high temperature-side auxiliary temperature range, a number of revolutions of the air blower is changed such that the number of revolutions of the air blower is lower than a number of revolutions of the air blower at the time of the low temperature-side auxiliary temperature range.   
     
     
         4 . The air conditioning device of  claim 1 ,
 wherein, when the temperature within the room is within the high temperature range, a number of revolutions of the air blower is changed such that the number of revolutions of the air blower is lower than a number of revolutions of the air blower at the time of the low temperature range.   
     
     
         5 . The air conditioning device of  claim 1 , further comprising:
 a current detection portion that detects a current which flows through the PTC heater,   wherein processing in which, in an early stage after the temperature within the room enters the low temperature range, the duty ratio is set higher than a duty ratio at the time of the intermediate temperature range, and in which, when the current detected by the current detection portion is lower than a predetermined value, the duty ratio is increased by a predetermined amount is repeated until the duty ratio reaches 100%.   
     
     
         6 . The air conditioning device of  claim 5 ,
 wherein, in the early stage after the temperature within the room enters the low temperature range, the air blower is driven at a first number of revolutions,   until the duty ratio of the PTC heater reaches 100%, the number of revolutions of the air blower is gradually decreased from the first number of revolution, and   when the duty ratio of the PTC heater reaches 100%, the air blower is driven at a second number of revolutions that is larger than the first number of revolution.   
     
     
         7 . The air conditioning device of  claim 5 ,
 wherein, when the current detected by the current detection portion is higher than a predetermined value, the duty ratio of the PTC heater is decreased by a predetermined amount.   
     
     
         8 . The air conditioning device of  claim 1 , further comprising:
 a compressor that operates a refrigeration cycle; and   a heat exchanger that exchanges heat with the air current generated by the air blower in a high temperature part of the refrigeration cycle,   wherein the air conditioning device can switch between a heating operation performed by driving of the compressor and a heating operation performed by driving of the PTC heater, and   when the heating operation by driving of the compressor is performed and the temperature within the room is lower than a predetermined temperature, the heating operation is switched to the heating operation by driving of the PTC heater.   
     
     
         9 . The air conditioning device of  claim 8 ,
 wherein, when the heating operation is started, the heating operation by driving of the PTC heater is performed, and   when the temperature within the room becomes higher than a predetermined temperature, the heating operation is switched to the heating operation by driving of the compressor.