Owing to its features, membrane distillation process is believed to have a great potential to be employed for the production of high-purity water from seawater, brackish water and industrial wastewater [7]. Membrane distillation systems have the ability to work with low operating temperatures and high concentration brines, which reduces both the specific energy required per cubic meter and the impacts of large amounts of brine disposal. Membrane distillation, unlike other membrane technologies can be easily coupled with solar energy due to its compatibility with the transient nature of the energy. Despite the advantages of solar membrane distillation, few experimental systems have been developed compared with the mature technologies: solar PV-driven reverse osmosis and solar distillation. The comparison of PV systems and thermal driven ones, with respect to long­time performance and reliability needs further research and therefore, more data is needed in order to compare both technologies [1].

The main objective of the MEDESOL project is to develop an environmentally friendly cost-effective of minimum maintenance and easy to handle desalination technology based in SMD, for a capacity range between 0.5 to 50 m3/day, to supply rural areas with water difficulties. The design involves the innovative concept of multistage MD in order to minimize the energy requirements. The system is developed to be supplied by compound parabolic solar concentrators (CPC), specifically designed to be energy-efficient at working temperatures. The project is divided into the following phases:

1. Design and construction of three MD prototypes for multistage concept, and an optimised solar static collector.

2. First tests at PSA facilities with saline solutions connecting the modules to a existing solar collector field and evaluation of the collector prototype.

3. Assessment of two different scenarios in applying MD, in EU and developing countries respectively.

4. Techno-economical and environmental assessment of pre-commercial systems to both scenarios.

To date, stage 1 has been completed and stage 2 is being carried out at PSA facilities. This communication will focus on phase 2 results.