Structural Design of the mCCHP-RES System - Design for Micro-Combined Cooling, Heating and Power Systems - page 131

Here will be considered only four such dimensions, namely: (a) general aspects
regarding the approach of the design problems, (b) system architecture that leads to
the system conceptual scheme, (c) typical actions of the design process, and (d)
structuring the design process in stages and steps.
Below, these dimensions of the search space will be discussed in more detail.

1.1 General Aspects

Design is a creative process by which new technical structures and processes (such
as devices, machines, installations, manufacturing processes, etc.) are developed to
satisfy speci

c needs. Design is an essential element in engineering practice. It may
be the design of an individual component, or of a system (an internal combustion
engine, for example) that consists of several components interacting with each
other. Perception of design ranges from the creation of a new device or process to
the routine calculation and presentation of speci cations of the different items that

make up a system. Design must incorporate some elements of creativity and
innovation, in terms of a new and different approach in order to solve an existing
engineering problem that has been solved by other methods or a problem not solved
before.
Design process involves the following four general aspects: synthesis versus
analysis actions; closed-ended versus open-ended approaches; optimal versus
acceptable solutions; concept, model, and prototype stages.

(a) Synthesis and analysis are two typical design techniques that may be applied.
Synthesis means selection of several components with appropriate features,
which are brought together to yield the characteristics of the overall system.
Establishing the properties and characteristics of various components that may
be incorporated represents an essential design action, because the components
selection is a very important factor in obtaining an acceptable or optimal
system.
Analysis means using of input data and information derived from basic
areas such as statics, thermodynamics,

fluid mechanics, and heat transfer in
order to evaluate and to compare the operating parameters and the perfor-
mance indicators of system.
Frequently, synthesis and analysis are employed together in the develop-
ment of a system, by selection of the components and analysis of the system.
Standard items such as valves, control sensors, heaters, ow meters, and

storage tanks are usually selected from catalogs of available equipment.
Similarly, pumps, compressors, fans, and condensers may be selected, rather
than designed, for a given application. Selection of components needed for a
system will be considered only as a first step in the design process. The second

step is analysis of the system as a whole.