Design Aspects of Energy-Efficient Systems

In the design of air-handling systems, a reasonable energy efficiency can be achieved by relatively simple means, just paying attention to some basic prin­ciples.

To give the designer some advice, many recommendations exist in litera­ture. Some general recommendations can be found in prEN 13779 for design­ing the air distribution system for low energy consumption. These include giving a certain target level for power consumption [the so-called SFP class. SFP means specific fan power, the ratio between the input power of fan mo­tors and the total airflow, in W/(m’s-1)].

Tables 9.20 and 9.21 present recommendations for maximum pressure drops of components in the supply and extract air systems in order to achieve a certain target level for power consumption in the whole system. In category “Low," this target level is 1500: in “Normal,” 2500; and in “High” 4000 W/(m3/s).

The selection of components to match the target level can be based on the default maximum pressure drop for each component. If a certain component

TABLE 9.20 Recommended Maximum Pressure Drops for Specific Components in Supply Air Systems

Pressure drop in Pa*

With higher pressure drop is selected (e. g., because of its higher filter class), then the overall target can be achieved by lower pressure drops of other com­ponents. For industrial applications, however, the figures in prEN 13779 are not necessarily valid due to the special demands of the production processes, but still their relevant parts can be taken as a design basis. The design process will end up in specific fan power (SFP) categories for each individual air han­dling unit (SFPV)—not only as a target value, but as a measurable design value or even as a guarantee value.

These issues are covered in more detail in DGB, Volumes B and C. Here, just a few basic tools have been introduced as guidance toward energy effi­cient air distribution systems in industry.

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