Page 314 - Applied Photovoltaics

Appendix

H

SYSTEM DESIGN

FOR PV-POWERED

WATER PUMPING

H.1 INTRODUCTION
Aspects of insolation data manipulation are discussed in preparation for designing a
stand-alone, directly-coupled PV powered water pumping system. This is followed by
an analysis and discussion of typical PV module characteristics and output and the
relevance for water pumping system design. An example system design is provided,
including discussion of each part of the procedure.

H.2 INSOLATION DATA MANIPULATION
Determine the maximum (solar noon) daily light intensity (I) incident on the array (at
inclination angle ȕ for each of the design months, for both sunny days (I s ) and typical
cloudy days (I c ). Refer to Chapter 1 for further details about insolation data and note
that various computer programs are available to help with such calculations
(Silvestre, 2003). For our purpose here we use an approximation that discriminates
between ‘sunny’ and ‘cloudy’ days (see Chapter 1, Section 1.8.3.2). Using Eqn.
(1.19) from Chapter 1 (Hu & White, 1983), in conjunction with Fig. H.1, we get, for
sunny days

1
.
.
1
I 353 u 7 AM . 0 678 u 10 usin ȕ Į (H.1)
0
.
si