By Nina Wolgelenter
Over the last few decades, several factors have changed the way aquatic facilities condition indoor air. Contributing elements to these changes include the type of chlorine used in the water, the water supply provided by the municipality and fluctuations in heating, ventilation and air conditioning (HVAC) needs. Combined, these elements significantly augment the air quality and, subsequently, the comfort of the facility regardless of the season or location.
Without proper ventilation, HVAC systems can contribute to poor indoor air quality (IAQ) concerns; however, with the introduction of highly evolved ventilation systems, along with high-volume low-speed (HVLS) fan technology, a more favourable, cost-effective environment can be created for swimmers, coaches and spectators alike.
In large natatoriums it is often difficult to achieve uniform temperatures and distribute ventilation with traditional air handling systems due to the sheer size of the space. The addition of large fans decouples air distribution from the HVAC system, allowing for low-energy air circulation, which increases the effectiveness of the ventilation supplied to the space.
The design and operation of indoor aquatic facilities is an exercise in energy conservation and proper engineering. To keep up with modern standards, both new and existing facilities often need to be renovated. To contend with high-energy costs, facility managers are researching opportunities for energy conservation by finding ways to incorporate HVAC efficiencies into their facilities.
The swimming centre at the University of Texas (UT Austin), built after the 1972 Summer Olympics, set the bar for large, indoor natatoriums with its 2.7-m (9-ft) deep competitive pool and adjacent dive pool. Three decades later, the facility was in need of upgrades with respect to its air quality control. The unique criterion involved in maintaining a quality environment for this facility resulted in an innovative system that controlled the chloramines in the space while taking advantage of waste energy to maintain comfort.
“Air movement was a big challenge due to the large Olympic-size swimming areas and the parameters that were established to accommodate the athletes,” explained Shawn Allen, a mechanical engineer and LEED AP with Jose I. Guerra, Inc., who served as principle on the project.
The potential for chloramine bubbles to form at the breathing zone (water surface) was a given; therefore, creating a way to disperse this gas was established in the initial stages of the project.
During renovation, the ventilation system was completely revamped using computational fluid dynamics (CFD), a computer simulation of airflow, and building information modelling (BIM) to help determine the best system that would provide comfort, as well as improved air quality.
“Through the use of CFD and BIM we were able to produce a model of the space and establish air flow patterns and velocity profiles that optimize air movement while minimizing evaporation and negative cooling effects on athletes,” said Allen.
As a result, the facility incorporated carbon gas-space filtration and increased the amount of outside air that was brought into the space rather than simply recirculating existing air. Fans were also installed throughout the pool complex to aid this process, said UT Austin’s facility director, Charles Logan.
“We have a daily setting for these fans, but at night when the facility isn’t being used, three things happen: release valves open in the building; fans operate at full speed; and 100 per cent outside air is brought in to flush out the air that circulated throughout the day,” Logan explained.