Publication Details
Abstract
The aim of this study is to evaluate and improve the thermal performance of a flat plate solar collector (FPSC) focusing on the water flow rate and the addition of a reflective mirror under the specific climatic conditions of Kirkuk, Iraq. This study combines theoretical modeling and experimental testing to reduce the gap between simulation and actual operation improvements and the associated real-world constraints of FPSCs. By modeling solar radiation and energy balance equations, practical experiments were conducted using a plate solar collector model designed and implemented in a way that accepts testing several parameters to conduct a detailed thermal analysis of the collector. The results demonstrated that the low-flow condition (0.55 L/min) achieved the highest overall daily efficiency (28%), attributed to favorable thermo-hydraulic balance and reduced optical losses. Although higher flow rates improved instantaneous thermal stability, they reduced the net efficiency due to smaller inlet-outlet temperature differences. The 120° reflective mirrors enhanced morning and evening performance, while the 90° mirrors increased midday heat gain but suffered from angle-dependent losses. Furthermore, the use of single-layer glazing increased convective and radiative heat losses across all cases. Overall, the findings emphasize that temporal continuity of energy gain is more critical than instantaneous efficiency peaks. The novelty of this research is that specific climatic conditions—such as the semi-arid conditions in these study experiments—require tailored solar collector designs. The results indicate that incorporating multi-layered glass and adaptive mirror alignment can further improve system performance in local solar heating applications.