Heat exchanging system of ventilating device

A ventilating device comprising:

• a housing having an outdoor air passage and an indoor air passage;
• a shaft rotatably supported by the housing, the shaft being rotatable about an axis which is substantially perpendicular to a direction of an air flow flowing in at least one of the outdoor air passage and the indoor air passage;
• and
• a plurality of heat exchanging elements mounted around an outer circumferential surface of the shaft, the heat exchanging elements being rotatable on the shaft by the air flow to exchange heat between air in the outdoor air passage and air in the indoor air passage,
• wherein each of the heat exchanging elements has a concave surface and a convex surface opposite to the concave surface, wherein when the concave surface faces an inlet of one of the outdoor air passage and the indoor air passage, the convex surface faces an outlet of the one of the outdoor air passage and the indoor air passage.

A ventilating device comprising:

• a housing having an outdoor air passage and an indoor air passage;
• a shaft rotatably supported by the housing, the shaft being rotatable about an axis which is substantially perpendicular to a direction of an air flow flowing in at least one of the outdoor air passage and the indoor air passage;
• a plurality of heat exchanging elements mounted around an outer circumferential surface of the shaft, the heat exchanging elements being rotatable on the shaft by the air flow to exchange heat between air in the outdoor air passage and air in the indoor air passage;
• a hub on the shaft;
• and
• a support rib along an outer circumferential surface of the heat exchanging elements, each of the heat exchanging elements extending from the hub to the support rib,
• wherein each of the heat exchanging elements has substantially a same curved shape.