MILK PASTEURIZATION USING SOLAR CONCENTRATOR WITH TRACKING DEVICE

Abstract

Milk pasteurization process consumes a large amount of energy, using of solar energy for pasteurization process reduces the required conventional energy. Experimental study was conducted to equip a solar concentrator with dual axis sun tracking device and utilizing it for milk pasteurization. The tracking device was a closed-loop system, it was worked based on the contrast of sunlight levels using light-dependent resistors (LDRs) and op-amp chip. The thermal system was comprised of solar parabolic dish, energy conversion subsystem, and heat exchanger. The system was able to pasteurize about 260 ml of milk at 73 ˚C in average time 110 seconds. The average hourly productivity of solar pasteurized milk was about 7.5 liters. The tracking device was able to track the motion of sun and keep the solar concentrator in a straight axis to the sun, and it had a feature of the low cost. The results indicated that the tracking device was led to increase of the cumulative daily heat gain by approximately 59 %. The temperature of the absorber plate was reached 190 ˚C with the automatic tracked concentrator while it was 91 ˚C with the non-tracked on March 2016.