PURPOSE: To control the formation of frozen cakes in an exhaust passageway and prevent the shortage of an exhaust air quantity by thermally connecting the exhaust passageway to an air feed passageway, both being on the upstream side of a heat exchanger, with a heat pipe.
CONSTITUTION: The subject ventilator has: an exhaust passageway 21 for sucking indoor air and exhausting it to the outdoors through a heat exchanger 8; and an air feed passageway 22 for sucking outdoor air and feeding it into a room through the heat exchanger 8 where the outdoor air exchanges heat with the indoor air to be exhausted. A heat pipe 23 is disposed in such a manner that one end thereof is positioned in an exhaust connection port 9 at the inlet end of the exhaust passageway 21 while the other end thereof is positioned in an air feed connection port 10 at the inlet end of the air feed passageway 22, respectively, whereby both the passageways 21, 22 are connected thermally to each other. A fin 24 made of a shape memory alloy is provided at each of both ends of the heat pipe 23. Both sides of this fin 24 are usually closed almost in parallel with each other like folded wings of a butterfly and are so formed as to open at a preset temperature. By such means, when a difference between an indoor temperature and an outdoor temperature is caused, heat is transmitted from the exhaust side to the air feed side through the heat pipe 23, and outdoor air is preheated before entering the heat exchanger 8, thereby preventing dew condensation from occurring on the heat exchanger 8 and frozen cakes from being produced in the exhaust passageway.
TOIDA MASARU
KITAZUMI MOTOI
