EXPERIMENTAL INVESTIGATION ON: EFFECTS OF SOLAR FLUX, TEMPERATURE, CURRENT, VOLTAGE, SPEED OF WIND AND TIME VARIATION AND THE EFFICIENCY OF THE SOLAR PV ON A DC COMPRESSOR

The development of solar refrigerators for use during the daytime has been found to be feasible, however, fluctuations in solar radiations during the daytime is a challenge for direct coupling of the solar refrigerator to the solar panels. The fluctuations in the solar radiations result in variations of the current and voltage from the solar panels. Huge battery banks are therefore always needed to stabilize energy supply to solar refrigerators (which use DC compressors) even when operated during the daytime. In this study two multimeters were used to measure both voltage and current. The Flux DAQ was also used to measure both the temperature of the refrigeration space (Trs) and ambient temperature (Tab) to observe the effects of solar flux, temperature, current, voltage, speed of wind and time variation on an open circuit test on a solar PV panel. The electrical efficiency of the solar PV model using the data from the open circuit test was also investigated. The experimental results indicated that the variation in temperature during the day was not directly proportional to the time. The effect of voltage of solar PV and solar energy results shows that, at a time of 13:00 GMT the temperature was 36.1°C and then increased from 36.6°C to 40 ℃ at 14:00 GMT and finally gradually decreased to 26.5 ℃ at 18:00 GMT. This shows that, fluctuations occurred during the day. In addition, the influence of current and solar flux was observed and the results indicated that, at exactly 7:30 GMT in the morning both the solar flux and current increased with time. The impact of current on the compressor also shown that at 7:30 to 18:00 GMT, the current was less than the start-up current of 2.08 A of the compressor. This also shows that the compressor could only operate at a start-up current of 2.08 amps and beyond. Furthermore, the effect of temperature and solar flux showed that, the solar flux increases as the temperature decreases during the day. The influence of power with voltage showed that, initially the curve followed the normal P-V characteristics but later observed a rough pattern as a results of irregular irradiations and temperature effect during the data collection. The electrical efficiency of the solar PV model result indicated that, the surface area of the solar PV is 1.6368 m2 and therefore the electrical efficiency of the solar panel was 14.08 %. This implies that, the system can convert 14.08 % of the sun's energy to run the load.