Panasonic PAW280MAH2 Instructions d'exploitation télécharger pdf (Page 11)

Ventilation theory and air handling units

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-

cically conditioned before being supplied to the target room, so that it meets the dened indoor

air requirements. “Conditioning” means treating the ambient air by ltering, heating, cooling,

humidifying, dehumidifying etc.

Room with defined requirements:

· Temperature

· Humidity

· Pressure

· Ventilation

Return airSupply air

While the conditioned air (supply air) is being introduced to the building or room, return air,

which no longer meets the dened 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midity) is withdrawn from the room and rejected to the outside.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 inltration

● Ventilation: ranging from 4 to 8 complete air changes per hour

In order to full the ventilation demands and to meet the recommended indoor air requirements,

mechanical ventilation systems comprising air lters, supply and return air ventilators, cooling

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Panasonic PAW280MAH2 Instructions d'exploitation Page 11