| 摘要 |
PROBLEM TO BE SOLVED: To provide an outside air treatment device that can more securely prevent dew condensation generated on a heat exchanger used as an evaporator.SOLUTION: In a dehumidification mode, a first heat exchanger 4 is made to function as a condenser, and a second heat exchanger 5 and a fourth heat exchanger 7 are made to function as evaporators. Based on a superheat degree of the second heat exchanger 5, a total expansion valve opening is determined. Based on a temperature of air output from the second heat exchanger 5 and a dew point temperature of the air, a deviation expansion valve opening is determined. Based on the total expansion valve opening and the deviation expansion valve opening, openings of a first expansion valve 18 and a second expansion valve 19 are set. Thus dew condensation of air passing through the second heat exchanger 5 can be prevented. In a humidification mode, an operation reverse to that in the dehumidification mode is performed, so as to enable prevention of dew condensation of air passing through the first heat exchanger 4. |
