A preliminary assessment of the dimensioning of both solar field and storage system is based in the simulation results obtained for a system without backup energy. This assessment is based in two parameters: the capacity factor, CF (the ratio of annual values of mechanical energy produced by the solar cycle and the maximum mechanical energy that could be produced by the cycle operating continuously at full load), and the global solar to shaft power conversion efficiency, □ SORC, (the ratio of annual values of mechanical energy produced by the solar cycle and solar energy incident on the solar field) calculated with equations 2 and 3, respectively.

VT, annual

Wyj, x 24(^ / day) x 365(days / year)

VT, annual

Г SORC ~

KQcol, annual

The results obtained for both cycles at the three tested locations are presented in figure 3.

These results allow a parametric analysis of solar field area and storage time dimensioning, revealing the effect of storage time increase over solar to shaft power conversion efficiency results. For cycle 2, these results are more limited than those obtained for cycle 3, which reveal a wider range of storage capacity volumes leading to increased system efficiency.

The results presented in table 4 allow a comparison of the dimensioning of the system, at the three tested locations, after a reference condition of (CF = 0.3, maximum r/SORC).

Fig.3 — Capacity factor (CF) and solar to shaft power conversion efficiency (nSORC) results obtained for yearly
simulations of cycle 2 and 3 at Almeria (SP), Cairo (EGY) and Moura (PT)