A comprehensive experimental investigation and dynamic energy modeling of a highly efficient solar air heater with octagonal geometry

Abstract

This research study developed an innovative high-efficiency solar air heater (SAH) employing symmetrical geometry and a flat absorber plate. Also, an experimental setup of the proposed SAH was designed, fabricated and tested during the application in the winter season. Accordingly, comprehensive information including a list of measurement instruments, an experimental procedure, and a measurement strategy, is being presented. As a critical outcome, the maximum difference between ambient temperature and system outlet temperature for three different inlet airflow rates containing 0.046, 0.034 and 0.022 kg s−1 were 10.75, 14.24 and 18.56 °C, respectively. Moreover, the daily thermal efficiency of SAH has been analyzed. The empirical results reveal that the average daily energy and exergy efficiencies of the proposed SAH were 78.73 % and 32.87 %, respectively. Also, based on the results of economic feasibility study, the fabrication of the proposed SAH is cost-effective with a simple payback of 5.17 years, and an internal rate of return of 23.91 %. Finally, time-dependent mathematical modeling was developed, by coding in MATLAB software and solved by analytical methods, to investigate the dynamic heat transfer among system components as well as the hourly thermal performance. To validate the model, the deviation of actual against modeling values was examined by calculating the mean absolute percentage error. The results demonstrate that with an error of less than 3 %, the model has acceptable accuracy at predicting temperature values.