Water curtain walls, also known as wet curtain walls, consist of water curtain panels and frames, commonly used in negative pressure ventilation and cooling systems. In such systems, negative pressure fans are used to extract polluted and hot air from indoors, while the water curtain wall opposite the fans facilitates the intake of fresh air. As the outdoor hot air passes through the wet holes of the water curtain wall, it undergoes a heat exchange with the water, getting filtered and cooled.