The concept of integrating cooling systems with photovoltaic-thermal (PVT) collectors is not new, although it has yet to be widely commercialized. Such systems have the potential to reduce building energy consumption since they can provide combined power and heat generation. Thus, the current work proposes an innovative water-based PVT system coupled with phase change material (PCM) capsules (PVT-PCM panel) and operating in both active and passive cooling modes to maximize the performance of photovoltaic panels in terms of power generation and thermal utilization. Unlike prior PVT systems, the current one achieves a higher electricity generation and heat storage capacity with a lower frictional power to meet the requirements for practical applications. Several sets of experiments were conducted in Cairo, Egypt, under real outdoor climatic conditions, to assess the overall performance of the PVT-PCM panel under various operating scenarios, with the results compared to those of a naturally air-cooled reference PV panel. According to the results, at 3 L/min cooling water flow rate, the actively cooled PVT-PCM panel achieved the highest electrical and thermal energy gain, translating to a maximum cumulative overall efficiency of 74.1%, compared to 34.6% and 12% for the passively cooled PVT-PCM panel and the reference PV panel, respectively.