Analytical and experimental investigation on evacuated tube solar air collector with inserted baffles

Abstract

Solar energy seems to be a potential option for addressing the issues newlineconcerned with the usage of fossil fuels. This alternate energy can be efficiently newlineutilized for fulfilling the heating needs of domestic applications as well as newlineindustrial processes. The solar devices used for satisfying the heating newlinerequirements are termed solar thermal collectors. The most commonly preferred newlinecollectors for low and moderate thermal applications are stationary type newlinecollectors. Stationary type solar collectors such as Flat Plate Collectors (FPC), newlineevacuated tube collectors are frequently used for low and medium temperature newlineapplications especially in the fluid temperature range around 60-100 °C. Mostly, newlineflat plate collectors are used to fulfil the requirements. However, FPCs suffer newlinefrom lower thermal efficiency due to higher convective heat loss coefficients, newlineeven after the introduction of many heat transfer enhancement techniques like newlinefinned absorber, corrugated absorber, jet impingement, multipass, artificial newlineroughness, packed bed and integration energy storage medium, etc. Evacuated newlineTube Solar Collectors (ETSC) emerged as a prospective replacement for FPCs newlinedue to their improved thermal performance even at low insolation periods and newlinethey are capable of delivering the hot fluid in the range of 80 120 °C. newlineThe most of the research studies focused on the thermal performance of newlinethe ETSC at lower mass flow rates of working medium. But for industrial newlineheating applications, especially for drying of wet products in large scale. It is newlinealso found that the incorporation of metal heat exchanger resulted in increased newlinecost and weight and thus, it may not be suitable for rooftop installations. newlineTherefore, in this study, a novel method of inserted baffles is introduced for newlinedirect air heating applications in industrial needs for higher flow rates of air. newline newline