Development and performance investigation of a locally fabricated dish type solar concentrator for preheating brewery bottle washer water at Dashen Brewery in Gondar Ethiopia

Ethiopia has considerable solar power potential, with daily solar irradiance ranging from 5.0 to 6.5 kWh/m 2 (average 5.7 kWh/m 2 ) for the Gondar region, where the present study was conducted. The factories that manufacture beverages in Ethiopia use electricity or petroleum to generate steam and hot water for their processing procedures, which include washing bottles and pasteurization. This research paper examines the design, development, and performance analysis of a dish-type solar concentrator intended to preheat water for the bottle washer at Dashen Brewery Factory in Gondar, which requires hot water at 80 °C at a flow rate of 840 l/h. A prototype with an aperture area of 2.59 m 2 was developed using locally available materials and tested experimentally during three months (February, March, and May) from 9:30 AM to 4:00 PM. The system achieved maximum outlet water temperatures of 68–73 °C, depending on the test month, which is sufficient for solar preheating when mixed with conventionally heated water to reach the required 80 °C. The highest thermal efficiency achieved was 84.47% in February, corresponding to a useful heat output of 1414.19 W and exergy efficiency of 25.55%, while the figure of merit was 0.194. The system substituted 30.8% of the bottle washer's thermal energy demand. It has been found that the use of the system prevents emissions of carbon dioxide by 114.4 kg daily in comparison with heavy oil combustion and provides 30.8% of the thermal energy requirement. The economic analysis showed a payback period of 1.94 years.