Thermal performance of double-pass counter flow and double-parallel flow solar air heater with V-grooved absorber plate

Abstract

The performance of double-pass counter flow (model A) and double-parallel flow (model B) solar air heater with V-grooved absorber plate are numerically investigated. The mathematical models are written based on energy balance equations for each element of both models. The matrix inversion method is used to numerically solve the mathematical models for solar intensity (I = 350 − 950 (W/m2)), ambient temperature (Ta = 20 (°C)), mass air flow rate range of (ṁ = 0.02–0.09 (kg/s)), and opening angle of V-grooved absorber plate of (Ø = 60°). The results are presented in terms of: Air temperature rise, useful heat gain, thermal efficiency, and thermo hydraulic efficiency. Obviously when air mass flow rate increases, model (A) produces the highest air temperature rise, useful heat gain, and thermal efficiency. As air mass flow rate increases, the thermo-hydraulic of model (B) also increases while thermo-hydraulic efficiency of model (A) decreases from air mass flow rate (ṁ = 0.05, 0.06 and 0.07 (kg/s)) for solar intensities (350, 650, and 950 (W/m2)) respectively. In terms of thermal efficiency, the model (A) is more efficient than of model (B) by (26.8470 %, 27.8890 %, and 28.2496 %) for solar intensities (350, 650, and 950 (W/m2)) respectively. In terms of thermo-hydraulic efficiency, model (A) is more efficient than that of model (B) by (12.1046 %, 20.6830 %, and 25.1215 %) for solar intensities (350, 650, and 950 (W/m2)) respectively.