Investigation on Airflow Characteristics and Thermal Comfort in an Indoor Swimming Pool

The design of air conditioning system in an indoor swimming pool hall plays a critical role in providing the thermal comfort and hygiene environment. This research objected to studying the effect of the air curtain flows on heat and mass transfer by investigating the velocity, temperature and moisture distribution inside the hall of the swimming pool which is occupied by many spectators and swimmers.

The study carried out using computational fluid dynamics (CFD) simulation using a commercial CFD package, namely ANSYS Fluent 17.2. The CFD modeling techniques solved the continuity, momentum, energy, and species transport equations in addition to k-epsilon model equations for turbulence closure. Mesh element sizes used in the present work exceeded 5.6 million mesh element which allowed better and meaningful predictions of the flow regimes.

The study performed inside a semi-Olympic pool located at Bishop’s University in Sherbrooke (Quebec, Canada) by drawing the geometry of roughly trapezoidal shape and dimensions of (34.5 m×25 m×8 m) by SpaceClaim 3D modeling software for six different simulation cases. The investigation included the influence of the location and number of ventilation and air conditioning supply and extracts openings at the lowest ACH (Air Changes Per Hour) recommended by ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) and evaluated by Fanger’s model.

Improving thermal comfort of the occupied area around swimming pool and spectator stand area is the primary concern of this study, therefore, to achieve the adequate conditions of thermal and airflow pattern the inlet grilles concentrated in this area with different heights and shapes. The outlet grilles in configuration 1 are at the middle of the ceiling in swimming pool area and in the side walls of the spectators stand area. Also, the inlet grilles are at the height of 3m from the floor in the side walls of the swimming pool and at the back wall of the spectator area. Configuration 2 outlet grilles are located in the ceiling at spectator stand area to investigate the effect of changing outlet position. Configuration 3 the inlet grilles are changed to be in 30cm height from the floor at swimming pool area. Configuration 4 the inlet grilles in the spectator stand area changed to the fence at 30 cm. To study the effect of shape change configuration 5 used circular inlet as recommended from ASHRAE at the ceiling, configuration 6 is studied the combination of best results from configuration 1 to configuration 5 to achieve suitable thermal comfort for the hall.

The validation results show a good agreement between ANSYS Fluent 17.2 results and OpenFOAM software results. Moreover, the results of the comparisons between the 6 configurations revealed that the circular inlet in the ceiling at low-speed air supply shown better air distribution and thermal comfort in the spectators stand area than rectangle inlet. Also, the rectangle inlet in side walls in swimming pool area shows better better air distribution and thermal comfort than circular inlet at low-speed air supply due to the height of the hall, finally ACH for the water pool area and spectator stand should be different due to the number of persons per square meter