Heat exchanger type fan

The claimed invention belongs to heat exchange devices where the heat carriers do not mix, and may be used, for instance, in ventilation and air conditioning systems for heat exchange between the intake and the exhaust air streams. Heat exchange devices are provided for use in ventilation and air conditioning systems where the heat carriers do not mix with one another. According to one embodiment, a heat exchanger type fan includes a casing having two inlets and two outlets, and a double-sided centrifugal impeller. The casing is divided into two isolated chambers, and the chambers together with the impeller form two isolated centrifugal fans. The impeller is made of a solid dividing disk, with backward curved blades located on both sides of the dividing disk, and intermediate blades placed between the backward curved blades and located over a periphery of the dividing disk. A ratio of a length of the backward curved blades to a distance between the intermediate blades over a mid-radius of the impeller is at least 10.