Air Conditioner Having Cooling and Heating Functions

Abstract

Disclosed is a cooling and heating air conditioner capable of performing heating more stably, preventing frost formation on coils of an outdoor unit even at subzero temperature in winter by using first and second heat exchangers and an auxiliary expansion valve. The air conditioner according to the present invention comprises an electronic control valve opened when the outside temperature is less than a preset value, a first heat exchanger performing heat exchange between high temperature liquid coolant and coolant passed through the outdoor unit and an auxiliary expansion valve, and a second heat exchanger disposed in front of the outdoor unit to induct thereinto the high temperature coolant. Since the second heat exchanger heats up the outside air through heat exchange before supplying the air to the outdoor unit, evaporation of the coolant can be stably performed in the outdoor unit, while preventing frost formation. Accordingly, heating can be performed constantly.

1 . A cooling and heating air conditioner having an indoor unit, an outdoor unit, a compressor, and an expansion valve, further comprising:
 a thermometer for detecting temperature of the outdoor unit;   an electronic control valve opened and closed according to the temperature detected by the electronic control valve;   a first heat exchanger performing heat exchange between high-temperature high-pressure liquid coolant flowing in through the electronic control valve and low-temperature low-pressure coolant passed through an auxiliary expansion valve;   a second heat exchanger mounted around the outdoor unit to heat the ambient air of the outdoor unit through heat exchange between the coolant flowing in through the first heat exchanger and the outside air; and   the auxiliary expansion valve for decompressing the coolant passed through the second heat exchanger and supplying the decompressed coolant to the first heat exchanger.   
   
   
       2 . The air conditioner of  claim 1 , wherein the temperature of the outdoor unit is determined by difference of temperatures at an entrance and an exit of the outdoor unit, and the electronic control valve is opened when the temperature difference is less than a preset value. 
   
   
       3 . The air conditioner of  claim 2 , further comprising a return line for supplying coolant to the compressor, the coolant which is supplied to the first heat exchanger through the auxiliary expansion valve in a low temperature and low pressure state and heat-exchanged in the first heat exchanger with the high-temperature high-pressure liquid coolant flowed in through the electronic control valve.