Panasonic PAW560MAH2L Installation Instructions Manual page 11

Ventilation demands
Ventilation must meet the following demands:
● Provide outside air (oxygen) for breathing
● Control of indoor air contaminants
● Covering of the building's thermal loads (temperature and humidity control)
● Setting of uniform conditions in the occupied zone
As the outside or ambient air varies in temperature, humidity, contamination etc., it must be spe-
cifically conditioned before being supplied to the target room, so that it meets the defined indoor
air requirements. "Conditioning" means treating the ambient air by filtering, heating, cooling,
humidifying, dehumidifying etc.
Supply air
While the conditioned air (supply air) is being introduced to the building or room, return air,
which no longer meets the defined indoor air requirements (e.g. in terms of temperature or hu-
midity) is withdrawn from the room and rejected to the outside.
Thus, a constant indoor air exchange is maintained by the mechanical ventilation system.
Recommended indoor air requirements
Organizations concerned with setting quality standards for the HVAC industry (Heating, Ventila-
tion and Air Conditioning), like e.g. ASHRAE or Eurovent, give recommendations for indoor air
quality criteria depending on the intended use of the room.
The ASHRAE recommendations for residential and commercial applications are as follows:
● Temperature: ranging from 20 to 24 °C
● Humidity: ranging from 35 to 65 %rh
● Pressure: slightly positive pressure to reduce outside air infiltration
● Ventilation: ranging from 4 to 8 complete air changes per hour
In order to fulfil the ventilation demands and to meet the recommended indoor air requirements,
mechanical ventilation systems comprising air filters, supply and return air ventilators, cooling
Ventilation theory and air handling units
Room with defined requirements:
· Temperature
· Humidity
· Pressure
· Ventilation
Return air
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