Assessment of double-pass pin finned solar air heater at different air mass ratios via energy, exergy, economic, and env
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RESEARCH ARTICLE
Assessment of double-pass pin finned solar air heater at different air mass ratios via energy, exergy, economic, and environmental (4E) approaches Saleh Abo-Elfadl 1 & Mohamed S. Yousef 2 & Hamdy Hassan 1,3 Received: 3 August 2020 / Accepted: 9 November 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract In this study, an assessment based on energy, exergy, economic, and environmental approaches on a double-pass (DP) solar air heater (SAH) having pin finned absorber at different air mass ratios up and down the absorber is investigated experimentally. Four air mass ratios are considered: (i) all the air mass flow passes up the absorber and returns to pass down the absorber (DP), (ii) 2/3 of the airflow passes up the absorber and returns to mix with the remainder of air to pass down the absorber (2/3 DP), (iii) the same as (ii) but 1/3 of the air passes up the absorber (1/3 DP), and (iv) all the air mass passes only down the absorber (single pass, SP). For all mass ratios, the performance of pin finned SAH (P_SAH) is compared with that of flat SAH (F_SAH). The results indicated that the air temperature rise and energy and exergy efficiencies of P_SAH are highly greater than those of F_SAH. The highest average thermal efficiency of F_SAH is 56.7% obtained at DP flow condition, whereas the highest value of P_SAH is 65.21% obtained at 2/3 DP with an increase of 17.6% compared with F_SAH. Also, P_SAH has higher average exergy efficiency of about 34.7% compared to F_SAH. Furthermore, P_SAH achieves energy payback time (EPBT) lower than that of F_SAH, while P_SAH has higher embodied energy. The findings indicated that F_SAH at SP airflow pattern has the maximum energy cost (0.0427 $/kWh), whereas P_SAH at 2/3 DP airflow pattern achieves the minimum energy cost (0.037 $/kWh). Finally, the proposed P_SAH system appears to be more viable from exergoeconomic and enviroeconomic approaches compared to F_SAH. Keywords Finned SAH . Flat SAH . Double pass . Energy and exergy . Environment and economic . Mass flow ratio
Nomenclature A Inlet port cross-sectional area (m2) Cp Specific heat, J/kg K Ein Embodied energy in (kW h) EPBTen Energy payback time based on energy (years) EPBTex Energy payback time based on exergy (years) Enout Overall energy outlet (W) ˙ in Ex Exergy inlet (W) Responsible Editor: Philippe Garrigues * Hamdy Hassan [email protected]; [email protected] 1
Mechanical Engineering Department, Faculty of Engineering, Assiut University, Assiut, Egypt
2
Department of Mechanical Engineering, Benha Faculty of Engineering, Benha University, Benha, Egypt
3
Energy Resources Engineering Department, Egypt-Japan University of Science and Technology (E-JUST), Alexandria, Egypt
˙ out Ex ˙ heat Ex ˙ work Ex ˙ mass;in Ex ˙ mass;out Ex ˙ dest Ex
h I ˙ m n p R Rg,ex S T Q YC ZCO2 zCO2
Exergy outlet (W) Exergy of heat (W) Exergy of work (W) Exergy of inlet mass (W) Exergy of outlet mass (W) Exergy destruction (W) Specific enthalpy (J/kg K) Incident solar radiation (W/m2) Mas
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