| dc.description.abstract | In theory, Photovoltaic (PV) systems can be sized to meet any load demand. The size and
viability of such systems depend on the load demand and its variability, availability of solar
resource at the site, and the efficiency of the individual components involved between the energy
source and the load.
The design of a photovoltaic system, therefore, relies on a careful assessment of solar radiation at
a particular site. Although solar radiation data have been recorded for many locations in the
world, they have to be analyzed and processed before a sufficiently accurate estimate of the
available solar radiation for photovoltaic system can be made. Among the common statistical
characteristics computed from the solar radiation data for the purpose of solar system design, is
the expected number of days in a year or in a given period of time in which daily radiation data
falls within a specified range of values. Knowledge of the frequency of occurrence of periods of
successive days of low radiation is also needed as a storage requirement in a solar system. The
global solar radiation, and its angular dependencies on tilted surfaces is also of paramount
importance, since most solar collectors are always positioned on an inclined plane. In Chapter 2
of this work, daily data from the Meteorological Department for 8 years (1985-1992) of 9
stations representing the whole country fairly well, has been collected and analysed. The main
aim was to study the site potentiality for solar systems applications. It has been established that
the country receives ample solar radiation the whole year round, typical of an average insolation
of20MJ/m2 day' with little possibility of less than 13MJ/m2
A Photovoltaic system is composed up of several components, e.g. the solar panel, the storage
system, charge controller, maximum power point tracker etc. However, different types of these
components are made by use of various technologies which ineffect affects the performance of a
PV system. Knowledge of the performance of each component is of vital importance in the
design of the PV system. Secondly, the performance of the PV modules and other components
varies from place to place depending on the weather conditions at the site. Outdoor tests
performed over a period of time is the best way of evaluating the components, and hence, the
system performance. In chapter 3 of this work, a manual data acquisition method has been
designed and employed to characterize the two most commonly used photovoltaic modules for a
period of time. From these tests, the efficiency of the monocrystalline panel was found to be
10%, while that of the amorphous solar panel is 6%. However, the manual method has been
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found to be slow and inaccurate due to the rate of change in the weather conditions. Due to this,
an automatic data logger has been designed and implemented in Chapter 4, using the versatile
BBC microcomputer's Il\1HZ bus.
Since the capital cost is the major component of the solar systems, the srzing procedure
determines the cheapest combination of array size and storage capacity that will meet the load
requirements with an acceptable level of security over the expected lifetime of the installation.
Where 'cheapest' means the system with the lowest life cycle costs and 'availability' (reliability)
is the percentage of a specified period of years over which the system is likely to meet all load
demands. A software program in dBASE IV has been developed, to enable users and designers
to get the optimum size of the system, given the station of interest, latitude, albedo and load
demand as inputs. Also the software computes the economic analysis of different types of
energy sources given the number of years of interest, inflation rate etc. This enables users and
designers to evaluate the system with low life cycle cost given a number of energy supplying
systems. | en |
