Numerical analysis of the return flow solar air heater (RF-SAH) with assimilation of V-type artificial roughness

Abstract

A novel design of Return Flow Solar Air Heater (RFSAH) with different arrangements of baffles especially V-Type Artificial roughness is simulated and numerically analyzed with energy balance equations. To enhance the effectiveness of baffles, numerous studies have been conducted. The performance of the RFSAH is studied in terms of thermal efficiency, thermo-hydraulic efficiency, and optimization of baffle parameters. Maximum Thermal efficiency and thermo-hydraulic efficiency are found in RFSAH with baffle on both sides of the absorber plate and mass flow rate above 0.2kg/s. Sensitivity analysis of the influencing parameters is carried out and reported the best performance of the system on selective geometrical parameters (ψ=0.7, β=20%, e/H=1, p/e=0.8, α=60∘). The results obtained from the present model are validated with the published experimental results and have been found in quite reasonable agreement with an average error of 16.45%. Thermal and Thermohydraulic efficiency of RFSAH with a baffle on both sides of the absorber plate is maximum among baffles below, above, and on both sides of the absorber plate. It is observed that the thermal efficiency of RFSAH is greater than SF-SAH. The proposed optimum baffles roughness is suggested to increase the air upholding time period for more efficient output.

Keywords

• Numerical analysis
• Energy Balance Equations
• Thermal Efficiency
• Return flow solar air heater
• V-baffles