Systems Approach to Environmental Engineering

PART II: THE SYSTEM DESIGN PROCESS


EBW2409: SYSTEMS APPROACH TO ENVIRONMENTAL MANAGEMENT

3. CONCEPTUAL SYSTEM DESIGN

The system design process is divided into three stages namely, (i) conceptual design,
(ii) preliminary design, and (iii) detailed design and development.

Conceptual design is carried out at the System Level. It is the foundation on which the
other life-cycle phases are based (see Figure 3.1), and basically it entails the following
activities:

 Need identification,
 System feasibility analysis,
 Requirements analysis (i.e., operational; maintenance and support),
 Determination of measures of effectiveness (technical performance measures,
TPMs),
 Functional analysis and allocation,
 Synthesis, analysis and evaluation, and;
 System specification.

Note: A milestone is an important event in the development of something.

3.1 Identification of Need

The systems approach to management process begins with the identification of a "need,"
"want," or "desire" for one or more new entities, or for a new or improved capability. It
should be based on a real (or perceived) deficiency.

Example:
 Need for clean and safe domestic water for a community.
 Need for sanitation facilities for an informal settlement.
 Need for increased supply of sugar in the market, etc.

All the above needs should be based on documented evidence or available information.

The statement of need should be presented in specific qualitative and quantitative terms
and in enough detail to justify proceeding to the next step.

A complete description of the current deficiency and the real need is necessary. The
results should truly reflect a requirement, and this is met best by involving the customer in
the process from the beginning.

3.2 System Feasibility Analysis

Having defined the need, it is then necessary to:

(1) Identify possible system-level design approaches that can be pursued to meet that
need (e.g. import sugar or improve the efficiency of existing sugar production system
or establish a new sugar production system to meet the sugar deficit in the country);
(2) Evaluate the most likely approaches in terms of performance, effectiveness,
maintenance and logistic support, and economic criteria (evaluate the above system-
level design approaches based on these criteria), and;




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, PART II: THE SYSTEM DESIGN PROCESS


In case the need is to enhance sugar production in the country based on established
want then the evaluation process can be presented as in Table 3.1.

Table 3.1: Evaluation process of system design approaches
Evaluation criteria System-level design approaches
Import sugar Improve efficiency Establish new sugar
of existing sugar production
production systems system(s)
Performance
Effectiveness
Maintenance and
logistic support
Economic criteria
Type and maturity of
technology
Stability and growth
potential of
technology
Number of supplier
sources, etc.

Recommendations
Availability of
personnel
Availability of
materials
Availability of funds

(3) Recommend a preferred course of action considering the most feasible design
approach to be adopted, consistent with the availability of resources (i.e. personnel,
materials, and funds).

 Included in the evaluation process are considerations pertaining to the type and
maturity of the technology, its stability and growth potential, the anticipated life of
the technology, the number of supplier sources, etc.
 Where there is not enough information available, research may be initiated with
the objective of developing new knowledge for specific applications.




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