| Author | Attalage, Rahula Anura |
| Call Number | AIT Thesis no.ET-86-5 |
| Subject(s) | Solar collectors
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | There are various empirical correlations available for
estimating different radiation components. These have been
developed using a finite data base of limit e d number of
locations. Among them four widely used empirical correlations are
selected, and analyzed in order to see the prediction accuracy of
these correlations when applied to arbitrary locations. The hourly
data of 26 locations (data of a typical meteorological year, per
location) and hourly data of 4 Australian locations (data of 10
years per location, with some locations containing a typical
meteorological year) have been selected for this analysis. The
estimation of the prediction accuracy is based on the statistical
estimators of Mean bias error & Root mean square error, and on
the development of the probability density curves, in terms of
relative and absolute errors. The effect of the clearness index
in also emphasized in the analysis. Finally the analysis results
in a comparison of the prediction accuracies of different
correlations, and the limiting range within which the error
values reside for a particular correlation.
The second aspect of this study deals with yearly
collectable energy of principal solar collector type s . Gordon &
Rahl ' s yearly collectable energy correlations are reassessed and
validated against the results of hour by hour simulated actual
data, of US and Australian location respectively. The estimation
of the prediction accuracy is based on the same statistical
estimators as stated earlier and on the development of
probability density curves, in terms of relative errors. Two n ew
correlations are developed for estimating yearly collectable
energy for flat plate collector tracking about north -south polar
axis and two -axes. Validation and reassessment of the proposed
correlations s how that, the correlation for two - axes case seems
as good a s Gordon & Rahl ' s correlations. The effect of shading
and the use of anis tropic sky model on the predictions have also
been analyzed.
The final section of this study aims at proposing a
generalized procedure, in order to obtain hourly and daily
utilizability functions on any time scale, starting from a
location specific parameter, the clearness index. The proposed
procedure in the study deals only with the case of flat plate
solar collector deployed at any tilt, facing due south. Starting
with the location specific monthly mean daily clearness index on
a horizontal surface, monthly- hourly, monthly- daily and yearly-daily utilizability functions for flat plate, facing due south at
any tilt are derived. The obtained utilizability functions are
validated with actual data and compared with other empirical
correlations of utilizability. Finally the extension of this
proposed procedure on to concentrating collectors is also
suggested. |
| Year | 1986 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Reddy, T. A. |
| Examination Committee(s) | Prida Wibulswas ; Lasnier, France
|
| Scholarship Donor(s) | Deutsher Akademischer Austa uschidienst (DAAD) |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1986 |