DHI has undertaken an impressive number of such studies since the 1980s. The services are based on state-of-the-art technologies within numerical and physical modelling and on survey and measurement campaigns for the collection of hydraulic, meteorological, sedimentological, biological, and chemical parameters. The results of the investigations form the basis for the optimisation of plant design and plant operation schemes with regard to the discharge of cooling water and possible additives in the aquatic environment.

A numerical model study will in many cases include the set-up of DHI’s 3D model, MIKE 3. Different MIKE 3 modules are applied for hydrodynamics, sediment transport and water quality. A typical recirculation study comprises the establishment of a hydrodynamic model to simulate the current and dispersion of heat. The model is calibrated against measurement data. Subsequently, the model predicts the dilution and spreading of the discharged cooling water for combinations of intake/outfall layouts and plant operation schemes. The horizontal resolution of the model grid varies over the model area in order to enhance the resolution for the near-field area of the intake and outfall structures. A detailed analysis of the near-field dilution may be carried out to optimise the diffusor design.