Simulation tool for indoor air quality improvement in a covered swimming pool.

The use of hypochlorite for water disinfection is source of chloramines production, which are transferred to the atmosphere.Nitrogen trichloride (NCl3) is the main component, which is a major cause of respiratory and ocular problems for swimmers and lifeguards. This first part comprised a sampling campaign concerning the measurement of NCl3 in a swimming pool (Picardie-France) during 15 days (October 2001). This campaign concerned the air quality diagnostics and showed that the majority of detected levels were critical (P50 = 0,44 mg/m 3 ). In a second part the simulation of the NCl3 dispersion was conducted with two main simulation tools : TRNSYS (thermal simulation) and FLUENT (CFD simulation). In order to generate a source term in the dispersion model, a pollutant mass transfer model has been developed to predict the NCl3 concentration in the indoor atmosphere. The latter seemed satisfactory and values were injected into the 3D-dispersion model. The thermal simulation tool TRNSYS generated the following results : 1) the swimming pool thermal behaviour during one year, necessary to provide temperature and moisture values as CFD boundary conditions 2) the thermal building simulation versus the real energy consumptions 3) the possibility to make energy savings by inducing HVAC modifications. Fluent code enabled the visualisation of pollutant accumulation zones.