Contents lists available at ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv Experimental validation of the numerical model of air, heat and moisture flow in an indoor swimming pool Piotr Ciuman * , Barbara Lipska Department of Heating, Ventilation and Dust Removal Technology, Silesian University of Technology, Konarskiego 20, 44-100, Gliwice, Poland ARTICLE INFO Keywords: Indoor swimming pool Ventilation Air flow variables Measurement CFD prediction Experimental validation ABSTRACT Indoor swimming pools are facilities in which a ventilation system has a vital impact on the proper operation of the building, as well as the users' comfort, operating costs and the safety of the structure. The major problem in ensuring appropriate thermal-moisture conditions is the removal of moisture that is mainly gained from the surface of the water in the pool's basin. The aim of this paper was to experimentally identify the physical phenomena occurring in the actual indoor swimming pool and to evaluate whether the numerical model of the facility, developed with the use of Ansys CFX 14.5 software, correctly mapped these phenomena and how it should be improved in this field. Results of the experimental research of the air variables, carried out in various periods of the year, were used to identify the changes in the thermal-moisture conditions and to prepare boundary conditions for the numerical calculations, as well as to validate these simulations experimentally. The numerical model was improved with the use of the authors' own method of modelling moisture emission from the surface of the water. It was based on the implementation of literature formulas for calculating the value of this parameter in the software. The validation encompassed the indoor airflow pattern and the distribution of the air flow variables above the surface of the water and around the pool's basin. The improved numerical model was able to reproduce the actual conditions in the indoor swimming pool with good concurrence of the experimental and predicted values. 1. Introduction Indoor swimming pools are facilities for recreational, sporting and therapeutic purposes. Their most important part is the pool's basin, which is the main source of heat and moisture. The sources of heat are also: lighting, radiators, people, evaporating water, heat penetrating the building's envelope and solar radiation. The sources of moisture, besides the surface of the water, are: the moist surface of the floor, people, and water attractions. Heat and moisture gains must be re- moved by the ventilation system to prevent deterioration of thermal- moisture conditions in a facility, especially the increase of specific air humidity. In case of the lack of a ventilation system or if such a system was improperly designed, executed and operated, a series of negative phe- nomena may occur. They involve the thermal discomfort of swimmers and condensation of water vapour on cold surfaces, the temperature of which is lower than the indoor air dew point temperature. The latter can lead to i.e. fogging of windows, weakening of the building's struc- tural elements, as well as the formation of fungi and mould. The intensity of moisture evaporation depends on many factors, such as: the size of the surface of the water and the moist floor, the water temperature, the air temperature and relative humidity, the air velocity above the surface of the water, the number and activity of swimmers and the water circulation in the pool. The phenomenon of moisture evaporation from the surface of the water in the pool's basin is associated with the boundary layer between the indoor air and the surface of the water. The intensity of such evaporation is dependent on the difference in the partial pressure of the water vapour in the boundary layer and the indoor air. In the literature, many correlations that have been validated ex- perimentally can be found, on the basis of which the mass flux of evaporated moisture from the surface of the water can be calculated. However, there is no consensus among researchers as to the method of its calculation. The most well-known correlation for the calculation of moisture emission from the surface of water is the Carrier formula [1]: = + − m F r v p p ˙ (0.0888 0.0783 )( ) w w i (1) In this formula two constants are taken into account: 0.0888 W/ https://doi.org/10.1016/j.buildenv.2018.09.009 Received 2 April 2018; Received in revised form 5 September 2018; Accepted 6 September 2018 * Corresponding author. E-mail addresses: piotr.ciuman@polsl.pl (P. Ciuman), barbara.m.lipska@polsl.pl (B. Lipska). Building and Environment 145 (2018) 1–13 Available online 08 September 2018 0360-1323/ © 2018 Elsevier Ltd. All rights reserved. T