DEFINITION OF FLAT SOLAR COLLECTOR INCLINATION OPTIMUM ANGLES ON CONDITION OF SEASONAL CHANGE OF THE TILT ANGLE

Abstract

The way of definition of optimum angles of inclination of flat solar collector of the southern orientation to the horizon plane on condition of seasonal (winter, spring, summer, autumn) changes of tilt angle, taking into account sunshine probability around construction is developed. For every season of year curve dependences of the energy arriving on 1 m of the sq. plane of the collector of the southern orientation for the city of Sarny on collector tilt are brought to the horizon plane in degrees, taking into account sunshine probability. Also all four curves are reduced on one drawing that allows to compare conveniently them. The statistical duration of sunshine undertook according to observations of the actinometrical station in the city of Sarny, presented in the form of polynomial of the fourth degree depending on number of day of year, and maximum was calculated in the program developed by authors as solar time from rising till the sunset in this day of year.

The relation of statistical duration of sunshine to maximum (astronomical) was treated as sunshine probability in this day of year. Of course, such treatment quite approximate as actually it would be necessary to take the relation of statistical duration of sunshine over the collector's plane to the maximum (astronomical) duration of sunshine over the collector's plane. But there are no data on statistical duration now.

All curve dependences of the energy arriving on 1 m of the sq. plane of the collector of the southern orientation have one well expressed maximum that has allowed to define it for every season, previously having interpolated values parabolic splines, and, thus, to define optimum angle of inclination of the collector for this season. The method can be used (if statistics are available for the construction area) for other periods of the year, for example, spring-summer-autumn, given that in certain areas of construction snow may lie on the collector planes for a long time. Other periods of the year may also be used for not climate-related reasons, such as electricity schedules.

Keywords: flat solar collector, astronomical and statistical duration of insolation, the probability of sunshine, optimum tilt angle, integral atmospheric transparency coefficient, orientation of the solar collector, mass of atmosphere.