Numerical and experimental analysis of longitudinal tubular solar air heaters made from plastic and metal waste materials

Abstract

Recycling and reusing waste materials not only reduces environmental pollution but also contributes to the reduction of health problems and economic gain. In this study, plastic and metal materials reused in fabricating solar air heaters (SAHs) are considered. Accordingly, two tubular solar air heaters have been designed, fabricated, and experimented. The major objective of this work is to demonstrate the importance of utilizing waste materials in renewable energy-based technologies and their applicability in thermal energy production. In the first step of the analysis, the applicability of tubular-type SAHs has been studied numerically. The experiments have been conducted at two tilt angles including 90° and 32° and also at three flow rates including 0.012, 0.010, and 0.008 kg/s. The experimental findings showed that the efficiency of metal SAH and plastic SAH varied in the range of 36.33-50.96% and 31.60-47.06%, respectively. Also, enviro-economic costs for metal and plastic SAH were achieved as 8.02 and 7.55 $/year. Besides, the experimental results were predicted with ANN and SVM algorithms. The prediction success of the algorithms is discussed with four metrics (R2, MAPE, RMSE, and MBE). The outcomes clearly demonstrate the successful application of this simple and cost-effective tubular-type SAH manufactured from waste materials.