Executive Summary : | Solar air heating is one of the emerging technologies for replacing conventional air heating systems in industries to make the balance between supply and demand of energy in the future. The greater challenge for solar air heating applications is the poor thermal performance of collectors due to the low thermal capacity of air and absorber-to-air convective heat transfer coefficient, which needs design considerations, and to the extent possible, compensation. Many researchers are working on thermal performance improvement of solar thermal systems using various surface techniques like using baffles, fins, ribs, groves, etc. Among these twisted tape arrangements employed in different applications like heat exchangers and air conditioning for improving the rate of heat transfer. This result motivated many researchers to apply twisted tapes in flat plate solar air heaters and they also reported that considerable improvement was achieved. In this study, the investigators proposed a new idea of implementing twisted tape in solar evacuated tube air heater to improve its performance. For the preliminary study purpose, the investigators have fabricated a tubular type solar evacuated tube air heater without twisted tape with a capacity of 1.5 kWth and noted that the heat transfer coefficient was improved by 2.5 to 3.7 times when compared with the basic type. India's automotive industry is one of the largest and fastest-growing in the world. India is the second-largest motorcycle manufacturer in the world. The majority of the manufacturing of automobiles and automobile parts is cluster-centric. The Major automobile industry clusters in India are Maharashtra, Tamilnadu, Karnataka, and Haryana. So most paint shops are available in these places. The vehicle painting requires higher amount of energy for spraying and drying. The energy requirements are currently satisfied with the electricity and natural gas. The temperature of air needed is in the range of 90 to 150 °C at higher flow rate to achieve good aesthetic appearance. Further, hot air is used for removing the dirt and VOC on the surface during the pre-treatment process. ETC are the most preferable option to heat the air up to 150°C using solar thermal energy for industrial heating applications. Solar thermal energy applications are more suitable for use in paint shops for pre-treatment, drying, and air-conditioning. So ETC with twisted tape is to implement solar evacuated tube air heaters to address the low thermal efficiency problem and the application of this proposed system in paint shops in the automobile industries. The proposal contains two phases, the first phase focuses on the development of the enhanced ETC, and the next phase continues with techno-economic sustainability study for spray paint drying purposes in the automobile industry. |