Structural Design of the mCCHP-RES System - Design for Micro-Combined Cooling, Heating and Power Systems - page 141

Table 1 Comparison between the design approaches
Main feature
of the design
process

Closed-ended approach Open-ended approach

Initial data Initial data represent the system ' s

input (that is the primary energy
sources) and the system ' s output (that
is the heat, cold, and electricity
produced). These data are clearly
specified and imposed

Initial data represent only the
characteristics of the residence and the
area in which it is located. These data
are vaguely speci ed

Output
requirements

The imposed output requirements are
the useful nominal power distributed
between the components (heat, cold,
and electricity), which the system
must transmit to the residence

The imposed output requirements are
the functions that the system must
cover permanently, as thermal
comfort winter-summer or charging of
home appliances and other utilities of
the residence

Primary
energy
sources

Primary energy sources are imposed
and clearly speci ed while the area in
which the residence is located is
neither imposed, nor clearly speci ed

Primary energy sources are not
imposed, but must be from among the
ones available in the area in which the
residence is located, while this area is
imposed and clearly speci ed

System
structure

The system structure is clearly
speci ed and imposed

The system structure is not speci ed,
being established during design
process

Main system
components

The technical characteristics of the
main system components are
determined during the functional
design and represent the input data in
their manufacturing

The technical characteristics of the
main system components are
determined during the functional
design and are ensured through
selection from those available on the
market

Optimization
variables

Optimization is continuous and
achieved during technical design of
the main component by convenient
adjustment of their construction

Optimization is discrete
(combinatorial) and is achieved
during structural design of the system,
by adjusting the structure and
selecting the components

System-
residence
compliance

The system-residence compliance is
obtained by selection of a general use
system from those available on the
market, so that it might cover the
energetic demand of the given
residence

The system-residence compliance is
obtained by conceiving a system that
is dedicated to the given residence;
the system components are of general
use and are selected from those
available on the market

3 Initial Data Collection

After the first two steps in achieving the mCCHP system, namely Conceptual

framework and Manufacturer business plan, have been completed, the design
should be continued with the collection of all initial data that form the hypothesis of