The proper sizing of the components of a solar system is a complex problem, which includes both predictable (collector and other performance characteristics) and unpredictable (weather data) components. In this work the transient simulation program TRNSYS [4] is used.

The various systems investigated were simulated with TRNSYS using Typical Meteorological Year (TMY) data for Nicosia, Cyprus and Athens, Greece. TMY is defined as a year which sums up all the climatic information characterizing a period as long as the mean life of the system. Using this approach the long-term integrated system performance can be evaluated.

Petrakis et al. [5] have generated the TMY for Nicosia, Cyprus used in the present study from hourly measurements, of solar irradiance (global and diffuse) on horizontal surface, ambient temperature, wind speed and direction, and humidity ratio, for a seven-year period, from 1986 to 1992 using the Filkenstein — Schafer statistical method. The measurements were recorded by the Cyprus Meteorological Service at the Athalassa region, an area at the suburbs of the town of Nicosia. The TMY is considered as a representative year for the Cypriot environment. Using the same method Pissimanis et al.

[6] have generated the TMY for Athens, Greece.

Two types of flat plate collectors are considered, collectors painted with normal black and color paints with an emittance value of 0.9 and collectors with selective coatings with an emittance value of 0.1. The absorptance of the black collectors is 0.95 whereas the value for light color collectors is 0.85. This value applies to light-colored collectors irrespective of the actual color. The performance equations of the collectors considered are [1]:

TOC o "1-5" h z Type A — Black collector, a=0.95 and e=0.1: n=0.8319 — 4.2629 (ДП/G) (1)

Type B — Color collector, a=0.85 and e=0.1: n=0.7453 — 4.2648 (дп/g) (2)

Type C — Black collector, a=0.95 and e=0.9: n=0.7937 — 6.7128 (ДП/g) (3)

Type D — Color collector, a=0.85 and e=0.9: n=0.7109 — 6.7316 (дп/g) (4)