It is essential to enhance solar-powered manipulating plates, photovoltaic lamps, photovoltaic cells, and solar-powered water syphoning in order to take use of solar heat. The next generation of fluids, known as nanofluids, have thermal characteristics that are superior to those of traditional fluids. Nano fluids are crucial in many thermal applications, such as the solar power generation, heat exchangers, car industry. Using a nanofluid to forecast the heat transfer parameters of a flat-plate solar collector, a generalized Brinkman-type fluid model was constructed. The effect of thermal radiation is considered. The fractal fractional derivative is used to extend the classical model into generalized model, after which the numerical solutions are determined using the Crank–Nicholson technique. All the controlling factors are studied parametrically, and some additional significant findings are tabulated for visual representation. In the current study, a composition of different nano-sized solid particles, such as Single walled carbon nanotubes and Multi-walled carbon nanotubes, was conducted in a water-based fluid. It was found that adding the composition of single and multi walled carbon nanotubes to the working base fluid (water) can increase the heat transfer rate as compared to the traditional nanofluid, this improves flat-plate solar collector performance by increasing the capacity for absorbing solar radiation.