Investigation of combined parallel and triple-pass v-corrugated solar air heater: A numerical and experimental study

Renewable and safe energy sources have been used more in recent years because of rising energy needs and finite fossil fuel resources. A solar air heater (SAH) is a device that utilizes solar energy to warm air for diverse applications, including room heating, drying procedures, or ventilation. The major aim of the current study is investigating the performance of the combined utilization of grooved absorber and triple-flow air channel modification in a SAH using numerical modeling. Accordingly, CFD method has been used to model the heat and flow characteristics inside a parallel-flow v-grooved SAH (PFVSAH), a triple-flow v-grooved SAH (TFVSAH), and a combined-SAH. The experimental and numerical evaluation of PFVSAH was conducted under different climatic conditions and mass flow rates of 0.019 kg/s, 0.015 kg/s, and 0.012 kg/s. Additionally, a numerical comparison was made between PFVSAH, TFVSAH and combined-SAH. According to the numerical results, the calculated temperature differences in a TFVSAH are greater than those in a PFVSAH and less than in a combined-SAH. According to the experimental results, when the mass flow rate is 0.012 kg/s, the PFVSAH shows average thermal and exergy efficiencies of 59.51% and 29.09%, respectively. In PFVSAH, the highest temperature difference between the outlet and the inlet was 28 degrees C. The recorded values for the top heat loss coefficient (THLC) of the PFVSAH varied between 4.3 and 8.93 W/m2.