Design and Experimental Evaluation of Solar Water Pasteurization with Integrated Heat Exchanger for Water Treatment: Case study of Jimma

Abstract

Solar energy is one of the clean and environmentally friendly renewable energies gathered from the sun. It is the primary sources for all forms of energy. Water is one of the most important natural resources in the world. The safe drinking water availability is a high priority issue for the quality of life and human existence. A large number of people still have no access to safe drinking water in the study area. To this end, the present study design to make treated drinking water by parabolic dish solar collector through pasteurization. The main goal of this work is to carry out design and experimental evaluation of solar water pasteurization with integrated heat exchanger for water treatment. The water was supplied to the system from a 50-liter tank that kept at elevation point near to the system. The parabolic dish concentrator, which was covered with an Aluminum sheet, was used to reflect the beam radiation to the black painted cylindrical receiver that was mounted at the focal point of the collector. In addition, the study used double pipe heat exchanger to transfer heat from pasteurized water to the unpotable incoming water before entering to the receiver. The manual sun tracking system was also used to adjust collector aperture towards the direction of solar radiation. In addition, the mass flow rate of water was controlled manually based on the temperature level. There is sufficient sunlight that converted into the energy required for solar water pasteurization by parabolic dish solar collector in the study area. On the clear sky and sunny days, the test results indicated a high receiver temperature 219℃ at the value of solar radiation 816 W/m2 with the maximum volume flow rate 0.005 kg/s. As a result, the finding indicated that on an average, 60 liters of water could be potable by the system during a sunny day with the 46% thermal efficiency. The system prototype constructed at JiT mechanical laboratory and tested at normal weather condition.