Reflective Array Solar Water Heater for Milk Pasteurization

Abstract

The solar water heater is a method of utilizing solar thermal energy by storing heat energy in water which can be used directly. Solar thermal energy has a high utility potential. It has a power of 1 kW/m2 on average on the surface of the earth with energy up to 7 kWh/m2/day on average per year. One of the uses of the solar water heater is that it can be implemented in the milk pasteurization system. The research equipment consists of an accumulator vessel with an area of 2x2 m2 and a water pipe collector. The water that had been heated in an accumulator (thermos) was used directly as the heating source in the milk pasteurization process. Meanwhile, the most common heating method used in the pasteurization process is electricity and gas energy. The result showed that using 82oC of accumulator water, it took 12 minutes (14.48–15.00) to reach the milk temperature needed in the pasteurization process which is 70oC for 6.75 litres of milk. The efficiency of solar heat energy absorption by an accumulator is 47%. This value can be increased by increasing the volume of water.