The system described in the paper consists of three elements: supply system, water ozonizer and water circulation system. Schematic diagram of the system has been presented in Fig. 3.

1.1. Supply system

Photovoltaic test stand to conduct the research on using solar energy has been situated on the roof of the four-storey building in which the Institute of Electrical Engineering and Electrotechnologies is located.

The following elements constitute the system:

— photovoltaic panels BPS 275 BP Solar; total power 6x75W=450W,

— accumulator battery BP Solar 12V, capacity 640 Ah,

— control system BP Solar,

— Trace DR1512 inverter,

— PCL 818 HG Advantech measuring card,

— PC Pentium,

— CM 3 pyranometer,

— voltage divider system with 12V measuring card,

— analogue meters with current and voltage shunts in meter circuit.

In order to improve the usage of solar energy reaching photovoltaic panel buffer sources are usually applied which accumulate the surplus energy that is not used by the receiver. Accumulators are most commonly used especially because of the fact that photovoltaic panels generate direct current suitable for charging batteries. Electric energy is supplied from the charged accumulator to the receiver in case of the lack of the solar radiation or if it is insufficient. The system for swimming pool water treatment described in the paper will be used during summer season i. e. in the period of higher insolation. The investigations of real object will show whether it is necessary to apply accumulator batteries in the system. Our earlier considerations brought us to the application of the inverter with the controllable frequency at the output of the photovoltaic panel. This solution will allow for the selection of optimal frequency of the voltage supplying the ozonizer. The operation of the test stand has been presented below.

Photovoltaic system described in the paper enables continuous measurement of the insolation which allow for the estimation of solar conditions in Lublin. As the system for water ozonization is intended to be applied in summer season, only selected results of the measurements taken in June are presented in the paper. The measurements were taken between 1-3 June 2002. Solar battery was set at the angle of 30° (the whole year).

The investigations were carried out with the application of the computer equipped with the measuring card. Professional software Genie was applied to develop suitable measuring method. Essential parameters of the system such as solar battery voltage, current intensity, accumulator voltage, current flowing from and to the accumulator, current of the receiver and insolation have been measured with the application of PCL-818 measuring card.

Average insolation results have been presented in the chart (Fig. 5).

The insolation in June reached its maximal value of about 1100 W/m2 at 1 p. m.