Ventilation device and integrated air conditioning system having the same

An integrated air conditioning system, comprising:

• an outdoor unit including a compressor and a condenser to circulate a refrigerant;
• an indoor unit connected to the outdoor unit;
• an indoor temperature sensor configured to measure an indoor temperature;
• an indoor humidity sensor configured to measure an indoor humidity;
• a ventilation device connected to the outdoor unit and configured to exchange indoor air with outdoor air, wherein the ventilation device includes:
• a housing including an inlet flow path to suck outdoor air to an indoor space, and an outlet flow path to discharge indoor air to an outdoor space,
• a total heat exchanger in which air flowing through the inlet flow path and air flowing through the outlet flow path exchange heat with each other,
• a first heat exchanger disposed on the inlet flow path and configured to receive a refrigerant from the outdoor unit through a first refrigerant pipe,
• a second heat exchanger disposed upstream of the first heat exchanger on the inlet flow path and configured to be supplied with refrigerant discharged from the first heat exchanger via a second refrigerant pipe connecting the second heat exchanger to the first heat exchanger,
• a first expansion device disposed on the first refrigerant pipe to expand the refrigerant supplied from the outdoor unit to the first heat exchanger,
• a second expansion device disposed on the second refrigerant pipe to expand the refrigerant discharged from the first heat exchanger and supplied to the second heat exchanger;
• and
• a controller configured to:
• in response to the indoor temperature measured by the indoor temperature sensor being greater than a set temperature and the indoor humidity measured by the indoor humidity sensor being greater than a set humidity, control the ventilation device to be operated in a first dehumidification mode in which the first heat exchanger and the second heat exchanger are configured to cool and dehumidify the air as the first expansion device expands the refrigerant,
• in response to the indoor temperature measured by the indoor temperature sensor being less than the set temperature and the indoor humidity measured by the indoor humidity sensor being greater than the set humidity, control the ventilation device to be operated in a second dehumidification mode in which the first heat exchanger is configured to heat the air as the first expansion device does not expand the refrigerant, and the second heat exchanger is configured to dehumidify the air as the second expansion device expands the refrigerant,
• in response to a difference between the indoor humidity measured by the indoor humidity sensor and the set humidity being less than an end humidity value when the ventilation device is operated in the first dehumidification mode, control the ventilation device to be operated in a ventilation mode by turning off the outdoor unit or preventing the refrigerant from flowing into the first heat exchanger and the second heat exchanger, wherein the ventilation mode is a mode in which the first heat exchanger and the second heat exchanger are not operated and heat exchange is performed by the total heat exchanger, and,
• in response to a difference between the indoor humidity measured by the indoor humidity sensor the set humidity and being less than the end humidity value when the ventilation device is operated in the second dehumidification mode, control the ventilation device to be operated in the ventilation mode by turning off the outdoor unit or preventing the refrigerant from flowing into the first heat exchanger and the second heat exchanger.