Considering the growing interest in the possible applications of HAT technology, characterized by the introduction of the humidification tower (saturator), this work proposes a novel model to analyze the saturator under both offdesign and transient conditions. On the basis of this model, the TRANSAT code was developed and tested with experimental results from the pilot plant installed at the University of Lund in Sweden. Both off-design and transient analysis were performed. Saturator off-design analysis showed the main parameters that determined saturator operating behavior and, specifically, that saturator water and gas outlet conditions are mainly driven by the water inlet temperature and air/water mass flow ratio: these are the main variables to be used for controlling saturator operation. On the assumptions made for the transient analysis, relevant results were achieved. The saturator showed a fast response to all the input variations. In particular, its characteristic times were essentially determined by the fluid residence time in the humidification tower. With regard to plant control, the main conclusion is that the integration of the saturator and the power plant is not expected to be critical for the control of the whole system.
