Page 56 - Industrial Ventilation Design Guidebook

3.2 DESIGN METHODOLOGY DESCRIPTION 2 I

• Divide process into parts such that their inputs from and outputs to the
environment can be defined.
• When the process or subprocess is not well defined during the initial
period of design, obtain the data from similar processes based on recent
successful practices. Obtain and use more precise data as soon as possible,

Step 3; Building Layout and Construction
• Collect properties of building layout, structures, and openings and their
properties as basic values for load calculations.
• Complete zoning of building based on division of the process and
building layout.
• Make space reservations and add structures needed for ventilation
equipment.

Step 4: Target Level Assessment
• Define target levels for indoor (zones) and outdoor (exhaust)
conditions.
• Specify design conditions in which the target levels are to be met.
• Define target levels for the ventilation system, such as reliability, energy
consumption, investment, life cycle costs, etc.

Step 5; Source Description
Clarify characteristics of the sources and calculation methods for calcula-
tion of local loads.

Step 6: Calculation of Local Loads
Calculate loads from individual sources to the environment.
Step 7: Local Protection
Examine subprocesses (sources) in order to provide proper working con-
ditions near them (local zones) or to reduce emissions to the environment.
Step 8: Calculation of Total Building Loads

• Calculate total loads (heat, humidity, contaminants) from different
subprocesses and environment (building) to ventilated enclosure
(zones).
• Take into account that loads are usually time dependent.

Step 9: Selection of the System
• Select acceptable systems based on target levels.
• Compare acceptable systems in order to choose the most desirable one.
• Use systems that allow maximum flexibility in air flow rates and
control strategies when selection of systems is based on inaccurate
(preliminary) data on production processes, volumes, and raw materials
to be used in the building. Emission rates from these processes and total
loads might be changed during the detailed design step.
• Consider constraints on the system selection, if some equipment has
been already selected and installed in the earlier design period.