The „Ray-Tracer” software uses the Ray-Tracing method to study some physical phenomena and is useful to study and simulate the mechanisms that take place in the solar radiation concentration process from the non-imaging photovoltaic concentrators. The paper presents results of simulated experiments regarding the concentration of the radiation by a paraboloidal photovoltaic concentrator installed on the roof of a house in the insolation conditions of a clear sky day.

The geometric characteristics of the paraboloidal photovoltaic concentrator are: parameter p = 200 mm, input aperture radius R = 50 mm, height h = 62.5 mm, focal distance f = H0 = 10 mm, geometric concentration factor Cgeom = 6.25. The photovoltaic cell is placed in the focal plane of the paraboloid and has the radius r = 20 mm. The photovoltaic concentrators are placed on the roof oriented South, у = 0, and the inclination is equal with the latitude of the place 5 = 45 deg. The maximum value of the incidence angle on the input aperture to which the concentration produces is 6max = 30.06 deg. For the given case, the minimum value of the incidence angle is reached at noon in September, 6min = 1.507 deg. The theoretical factor of optical concentration is Coptic, teoretic = 3.98. For the given situation, the maximum optical concentration factor is Cmax = 3.57 in September at noon. The optical concentration factor, in the described experiments, is higher than 1 between 1030 o’clock and 14 o’clock. The maximum density of the solar radiant flow on the photovoltaic cell is reached in March, at noon, Brec = 2837 W/m2. The efficiency of the concentration varies between 12.31%(June) and 26.10% (September). A photovoltaic installation with the collecting area of 12.50 m2, with 5000 paraboloidal concentrators, provides monthly the electric energy quantity variyng from 71 kWh, in December, to 383 kWh, in March. The electric energy production satisfies the the need of a family and allows the monthly delivery, in spring, summer, autumn and winter of approximately 125 kWh to the national energetic system.

The following papers will refer to installations with paraboloidal concentrators at which the distance between the parabola’s peak and the photovoltaic cell is variable. The purpose of these papers is to determine the optimum position of the cell depending on the paraboloid’s peak so that the optical efficiency to be higher that 1 for a longer period of time.

Acknowledgments. This work was supported by the grant CEEX-247 References

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