Page 69 - Industrial Ventilation Design Guidebook

34 CHAPTER 3 DESIGN METHODOLOGY OF INDUSTRIAL AIR TECHNOLOGY
Step 2: Total Loads
Calculate total loads, taking into account the time dependence of the
loads.

Step 3: Check for a Source That Has Governing Role to Totaf Loads
• Check whether there is some single source that alone produces most of
the loads.
• If you are calculating the loads at first, there might not be a need to
reconsider at this stage.
• If the answer is yes,
• If construction is the main source, return to Building Layout and
Construction and reconsider whether there is something that can be
changed in building construction to reduce loads.
• Reconsider the target levels of local zone to reduce emission of a
single source.
• If the answer is no, reconsider the target levels of the main zone (general
ventilation), if loads cannot be reduced.

3.11 SELECTION OF SYSTEM

There are two different tasks in system selection: acceptance of systems based
on target levels, and comparison of acceptable systems in order to choose the
most desirable one.
Based on technical calculations the conditions achievable by different sys-
tems (ventilation, cleaning, etc.) are compared to target levels to identify ac-
ceptable systems. Dimensioning properties could be:
• Mass and heat balances
• Room flow models

Acceptable systems are compared to each other and the most suitable system
is selected on the basis of different parameters, such as power and energy con-
sumption and investment and life cycle costs. See Fig. 3.12. Tools for compar-
ison are energy balances and cost analyses.

Explanations of Fig. 3.12

Step J: Alternative Venti/ation/AC Systems
Select alternative ventilation systems for comparison.

Step 2: Alternative Air Distribution Systems
Select alternative air-distribution systems for comparison.

Step 3; Technical Calculations
Calculate the operation of different solutions.
Step 4: Comparison to Target Levels
• Compare conditions reached with different systems to target levels.