While the chemistry of cleaning the water is similar (filtration, carbon, and reverse osmosis), the engineering and functionality differ significantly between portable and stationary systems.
Size and Footprint: Portable units are designed to be compact, often mounted on wheels or placed in small carts. They can fit through doorways and in small treatment rooms, hotel rooms, or disaster shelters.
Heat Disipation: Standard RO systems reject a lot of water and generate significant heat. Portable units are designed to be more energy-efficient and often manage heat better to operate safely in environments without industrial plumbing.