Hybrid solar–thermal energy harvesting—Solar–thermal hybrid energy harvesting systems are a vital development in renewable energy technology, in that they have the ability to produce electrical power and potentially useful thermal energy simultaneously in the same footprint. The conflicting performances of these mechanical apparatus can be highly limited by inefficient heat transfer and ineffective transport of the working mass of liquids and gases, resulting in photovoltaic thermal degradation and high-level exergy loss. The goal of the proposed study is to optimize the heat and mass transport processes that occur in a hybrid solar–thermal mechanical system to make the most out of energy recovery and to guarantee long-term system performance reliability. The governing equations of continuity, momentum, and energy conservation were written in the form of three-dimensional numerical modeling based on the finite volume method (FVM). The genetic algorithm used was the Multi-Objective Genetic Algorithm (MOGA), which was applied to obtain the optimum geometry parameters, that is, analysis of the effects of variable cross-section microchannels on the attributes of the flow and thermal boundary layer disruption. According to the optimization results, at a Reynolds number of 2000, the suggested microchannel geometry raised the average Nusselt number by 43.5% when compared to a smooth channel configuration. As a result, the photovoltaic component's effective operating temperature dropped by 12.6°C, corresponding to a 9.3% increase in relative electrical efficiency. The hybrid system's highest thermal efficiency, net energy gain (76.8%), satisfied the acceptable 16.3% increase in pumping power requirements due to friction penalties. The results of the experiment indicate with no doubt that the optimization of the mass transport processes is a critical component of the facilitation of the high-quality thermal regulation. The results of the experiment indicate without doubt that the optimization of the mass transport processes is a critical component of the facilitation of high-quality thermal regulation. This optimization policy has presented a technically effective channel for the creation of high-grade, high-efficiency industrial solar collector equipment and has laid strong groundwork regarding the development of renewable energy technology that is sustainable and poly-generational.