Cogeneration power systems are a key area for improving energy efficiency by minimizing losses. This paper presents a theoretical investigation into the thermal and electrical performance of an enhanced photovoltaic/thermal (PV/T) system. A refined thermo-electrical model is developed to evaluate key performance parameters, including thermal and electrical aspects. The model incorporates advanced correlations for radiative heat losses and considers radiation heat transfer within the air duct. Four distinct system models are compared: (I) a glazing photovoltaic panel, (II) a glazing PV/T cogeneration system, (III) a glazing PV/T system with an absorber plate, and (IV) a glazing double-pass PV/T cogeneration system with an absorber layer. Analytical solutions are validated using experimental data from previous studies, with representative weather data from Egypt. Results show that model IV achieves the highest efficiency at 92% under peak solar radiation (12:00 PM), followed by Model III at 77%, while models I and II yield lower efficiencies of 29% and 61%, respectively.