Air versus water temperatures
The 2011 ASHRAE Handbook–HVAC Applications, states the ideal air temperature within a facility should be maintained 1 to 2 C (2 to 4 F) above the water temperature, but not above the comfort threshold of 30 C (86 F). If the water temperature exceeds the air temperature, some form of air movement is deemed necessary for cooling comfort. Ventilation systems alone are often designed to help supply enough air to a facility, but the addition of large-diameter, low-speed fans helps with the necessary step of delivering airflow to all parts of the room. At the same time, this air movement must be gentle enough to simply mix the air in the space without causing a draft that can chill swimmers exiting the water. With a typical AHU alone, achieving a well-mixed space in an aquatic environment can be very difficult. Large-circulator fans paired with variable speed drives allow air speeds at the occupant level to match the needs of the occupants and the HVAC system.
Natatorium humidity maintenance
Humidity control is crucial within all natatoriums, regardless of location and size. The mix of chemicals, condensation buildup, and patrons themselves creates IAQ concerns that occur in various ways, including corrosion of exposed and even hidden metal structures, as well as mold growth. With condensation buildup inevitable, large-diameter fans work with ventilation systems to ensure fresh air reaches the occupant level with steady, constant motion without causing a draft. (Condensation in this type of environment can occur on any surface below the dewpoint temperature of the air. This would likely include the walls, roof, and floor, but could be on the equipment inside the space as well.) Regardless of the method used to exchange air, it is important to keep it flowing around the solid surfaces to reduce condensation. If the air is cooler than the pool water, it will cause condensation and ‘misting.’
Without the proper precautions, indoor air quality issues are inevitable, but with the appropriate system put into place, aquatic facilities can focus on the athletes, knowing the air they breathe will not harm them.
Nina Wolgelenter is a senior writer for Big Ass Fan Co., a designer and manufacturer of large-diameter, low-speed ceiling and vertical fans in Lexington, Kentucky. She has a background in environmental education and journalism. Wolgelenter’s work on energy conservation, sustainability, and the impact of advanced fan technology has been published in magazines, newspapers, and online media outlets. She can be contacted via e-mail at nwolgelenter@bigassfans.com.
Christian Taber, LEED AP, serves as the senior applications engineer at Big Ass Fan Co. As head of the applications engineering team, he is responsible for assisting customers with energy conservation and thermal comfort-related projects that involve air movement strategies. Taber spent eight years as an engineer at Trane, focusing on building energy simulation. He is an American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE)-certified high-performance building design professional, a certified energy manager, and a committee member of ASHRAE 90.1 and 189.1. Taber is pursuing a PhD in biosystems engineering from the University of Kentucky, and holds a master of science in mechanical engineering and bachelor of science in chemical engineering, both from Iowa State University. He can be reached at info@bigassfans.com.
