Analysing the thermal characteristics of a two-pass solar air heater featuring triangular grooves
摘要
An enhancement in the transfer of heat in a double pass solar air heater (DPSAH) while keeping the pressure losses minimum is investigated numerically and experimentally in this work. Three consecutive days of real-time solar radiation during the winter season in the Meghalaya region are considered for the current study. The uniqueness of the design of the DPSAH, which contributed to its superior performance, lies in the formation of a triangular-shaped grooves attached to the lower portion of the absorber plate, along with the addition of CuO nanoparticles. 3-D modelling of the computational domain is analysed using commercially available Ansys Fluent 23.0 software. The RNG k-ɛ turbulence model with enhanced wall treatment has been considered to solve the governing equations. The length, width, and height of the DPSAH are taken to be 226, 100, and 10 cm, respectively. The prime investigation is to observe the influence of triangular grooves on the efficiency of the system. Two DPSAHs, one with flat absorber and the other with triangular grooved absorber are fabricated to compare and analyse the outlet air temperature, absorber plate temperature, and the system's thermal efficiency. Maximum thermal efficiency of 77.13% has been obtained at e/H of 0.6 and p/e of 5.66 when the mass flow rate (MFR) of air is maintained at 0.03 kg s−1, which indicates a remarkable improvement in thermal performance of the triangular grooved DPSAH compared to a flat-plated counterpart, by positively impacting the thermo-fluid characteristics within the domain of the heat exchanging conduit.