At Plataforma Solar de Almería (PSA), different commercial spiral-wound MD modules were tested
coupled to a solar thermal field composed of stationary flat plate solar collectors. One of them is
the Solar Spring module with a permeate-gap membrane distillation (PGMD) configuration. Two
modules from Aquastill based on a configuration of air-gap membrane distillation (AGMD) were
also tested. A characterization of the modules is presented based on an extensive set of experiments
carried out using simulated seawater. The performance was evaluated by measuring the production
of distillate per unit surface of membrane and the heat efficiency, calculated through the thermal
energy consumption. Also, the quality of the product was evaluated by measuring the conductivity
of the distillate. The tests were performed changing the most significant operational parameters in
order to characterize their effect on the performance of the system. The feed flow rate was varied
between 400 and 600 l h–1 and the temperature of the hot feed from 60 to 80°C. The results show that
the internal design of the module is very important, and the differences in the channel length in
these modules have a stronger effect in their performance for seawater desalination than the configuration
of the gap.