Page 48 - Industrial Ventilation Design Guidebook

2,! MAIN DEFINITIONS 13

Local ventilation systems can be divided into the following subsystems:
• Local exhaust
• Local supply, including air curtains (i.e., control of air flow using jets}
• Combined local supply and exhausts
Parts of subsystems include fans, ducts, and filters.

2.1.2.3 Methods for Room Air Conditioning: Basic Strategies
A detailed description of the methods for room air conditioning is pre-
sented in Chapter 8. Table 2.1 summarizes the strategies.

2.1.3 Process Air Technology Systems
2.1.3.1 Cleaning Systems
These include equipment for supply air and equipment for exhaust air and
gases. Cleaning of supply air is normally called air filtering, when the contam-
3
inant concentration upstream from the air filter is less than, e.g. 1-2 mg/m .
Also, chemical filtration can be applied for supply air.
There are many types of cleaning systems and equipment, for example:
• Dynamic separators
• Wet separators
• Electric filters
• Desulfurization equipment (SO X control}
• Denitrification equipment (NO T control)

2.1.3.2 Conveying Systems
These are mainly pneumatic conveying systems, in which impurities and
solid waste, but also materials or goods, are transported by air flows. The sys-
tems categories are low-pressure, medium-pressure and high-pressure systems,
depending on how heavy the impurities are that the system will transport.

2.1.3.3 Drying Systems
These systems and equipment are used, e.g., in paper machines, using air
or radiant drying.

2.1.4 Safety Air Technology Systems
These include, for example, smoke extraction systems. In ventilation and air
conditioning systems certain equipment can also require special safety mea-
sures (e.g., due to explosion risks}.

2.1.5 Definitions of Types of Air
The definitions of the types of air are presented in Fig. 2.3.

» Supply air
• Exhaust air