The building industry contributes to the world's CO2 emissions at an average of about 39%, which makes sustainable cooling and envelope solutions necessary. Although PBR facades are promising in the temperate climate, their combination of energy-carbon-comfort trade-offs at hot-humid conditions with high-irradiance conditions is not well studied. This paper fills this gap by parametrically optimizing the concentration of algae and the ratio of windows to the wall (WWR) to measure cooling-load reduction, biological CO2 fixation, and daylight-thermal trade-offs in cooling-dominated climates. A parametric analysis of an office building in Dhahran, Saudi Arabia, was done using a four-stage framework that combined 3D energy modeling and CO2 fixation measurement with algae concentration (10-90%), and window-wall ratios (WWRs). Results indicate that higher algal densities can significantly reduce cooling loads: the 90% PBR system reduced cooling energy use by 18.5% over baseline and sequestered 441 kg CO2/year. The fixation rate of 306 kg/year with reduced algal concentrations to optimize WWRs (≤50%) demonstrated that there exist trade-offs in design. Thermal and visual comfort in the indoor environment were maintained and validated by ASHRAE standards. Commercial adoption is hampered by high capital expenses and operational complexity despite the good environmental and energy performance. Integrating AI and IoT-based controls is proposed to enhance system responsiveness, efficiency, and longevity. This research advances bio-integrated building envelopes, providing actionable design guidelines for professionals aiming to achieve carbon-negative, climate-resilient architecture.