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Effects of a circular-shaped turbulator having varying hole numbers on energy and exergy efficiencies of a solar air heater

ABSTRACT In this paper, the energy and exergy approach was used to evaluate the performance of a new solar air (SAH) heater. The experimental tests were performed for a plain tube, circular-shaped turbulator having varying hole numbers (HN = 2, HN = 4, HN = 6) inserted inside the tube of SAHs and air mass flow rates (, 0.0033, 0.0044 and 0.0055 kg/s). The energy and exergy efficiency results obtained for various parameters in SAHs were evaluated at noon. The energy and exergy efficiencies of the plain tube of SAHs were computed as 50 ± 0.54% and 16.8 ± 0.54%, respectively. The energy efficiencies obtained with turbulators inserted inside the tube of SAHs for HN = 2 and 6 were computed as 58.3 ± 0.63% and 53.7 ± 0.59%, whereas the exergy efficiencies were calculated as 20.7 ± 1.00% and 18.4 ± 0.73% for  = 0.0055 kg/s, respectively.