Combined ventilating and air conditioning system

A combined ventilating and air conditioning system, comprising:

• an air conditioner, which comprises a compressor, a first heat exchanger for heating or cooling indoor spaces and a second heat exchanger, a refrigerant passage controller for guiding a refrigerant compressed by the compressor to the first heat exchanger or second heat exchanger according to a driving mode of the system, and an expansion device expanding a high-temperature and high-pressure refrigerant, the expansion device being provided between the first heat exchanger and the second heat exchanger;
• a first air duct for guiding outdoor air to the indoor spaces, the first air duct being capable of opening and closing;
• a second air duct for guiding indoor air to outdoors, the second air duct being capable of opening and closing and installed in such a manner that part of the second air duct intersects with the first air duct;
• a third air duct for guiding the indoor air to the outdoors, the third air duct being capable of opening and closing;
• a regenerative heat exchanger, being provided in an intersection between the first and second air ducts, for exchanging heat between the indoor air and the outdoor air passing through the intersection;
• and
• blowing fans for controlling airflows, being provided in the first air duct, in the second air duct, and in the third air duct, respectively,
• wherein the compressor and the second heat exchanger are provided in the third air duct.