| 摘要 |
An air-to-air heat recovery air ventilation unit 10 having a heat exchange unit 12, a fresh air flow path 14 and an extracted air flow path 16, both of the flow paths passing through the heat exchange unit whereby heat recovery can be effected. The air ventilation unit has a fresh air flow path obturator 18 (flap) and an extracted air flow path obturator 20; the obturators being operable to close the respective flow paths to a portion 12b of the heat exchange unit. The portion of the heat exchange unit can be in the range of twenty five percent to eighty percent of the whole heat exchange unit, preferably fifty percent. Preferably, each obturator is in the form of one or more plates, pivoted about the longitudinal centre line or a longitudinal edge. A method of air-to-air heat recovery air ventilation is disclosed. Heat exchange efficiency is maintained when a reduced level of ventilation is required. Reduction of the operating volume of the heat exchange unit results in reduced fan speed, power consumption and fan noise. The obturators can be controlled by a carbon dioxide sensor. |
