Performance analysis of using CuO-Methanol nanofluid in a hybrid system with concentrated air collector and vacuum tube heat pipe

Highlights: • The use of nanoparticle in the vacuum tube heat pipe system was analyzed. • CuO-Methanol nanofluid was determined to have more average efficiency in the high solar radiation values. • Ambient temperature was increased by 11 °C in the winter season with the proposed system. • Two mathematical models were developed in the study. -- Abstract: An experimental study was conducted to determine the effects of adding copper oxide (CuO) with 50 nm diameter into neat methanol (CH₃OH) on the energetic and exergetic analysis of a concentrated air collector with vacuum tube heat pipe at different air velocities (1, 2 and 3 m/s). The experimental results clearly indicated that the nanofluid application enhanced the thermal properties and provided better performance for heat pipe applications. Considering all air velocities together, the average efficiency for neat methanol and CuO-Methanol nanofluid was achieved by 65% and 64%, respectively. Additionally, the average specific exergy outlet values for neat methanol and CuO-Methanol nanofluid were calculated as 206 J/kg and 298 J/kg, respectively. In the experiments, it is seen that the efficiency values of the system using the CuO-Methanol nanofluid reached higher values, as the solar radiation values were higher. In conclusions, this paper distinctly suggests that the presence of copper oxide in the base fluid can be used in a concentrated air collector with vacuum tube heat pipe particularly at the high radiation conditions and positively affects the performance of the system.