This paper presents a computational study on the viability of wind-driven natural ventilation as a zero-energy retrofit solution for improving indoor air quality in small, enclosed sanitation spaces. Focusing on Nordic and Arctic regions, the work leverages abundant wind availability and low ambient temperatures to assess the effectiveness of a dome-shaped ventilator using CFD simulations. In the first stage, simulated suction velocities are validated against experimental data across a range of wind speeds and fan RPMs. In the second stage, CO₂ is used as a passive scalar to model odor dispersion from a realistic defecation event under an interpolated annual average wind speed for Reykjavik.
Three cases—static fan in dead air, rotating fan at 108 RPM under wind-driven conditions, and static fan under the same wind—are compared in terms of odor decay, air change rates, and CO₂ concentration fields. Results show that a static fan under direct wind exposure achieves faster odor clearance and higher ventilation rates than its rotating counterpart, where wind-induced rotation at subcritical RPMs introduces aerodynamic resistance. The findings demonstrate the potential of wind-assisted retrofits to provide low-cost, maintenance-free, and energy-resilient ventilation for sanitation and micro-spaces in extreme climates. The work supports key objectives in energy efficiency, sustainable building design, and passive environmental control strategies.