Indoor unit of a ventilation system, ventilator and air conditioner

摘要

In an air conditioner indoor unit having a fan or ventilator 3 and a heat exchanger 4, there are provided an upper casing 3a of the ventilator made from porous structure having air permeability, a lower casing 3b of a ventilator having airtightness, and an air chamber 10a formed at the back of the upper casing. It is stated that the air chamber 10a acts to improve noise absorption by reflecting back through the porous structure of the upper casing 3a the compressional wave ie acoustic energy. Other porous structure arrangements are described.