Boosting fresh water production
The 'Innovative applications of solar trough concentration for quality fresh water production and waste water treatment by solar distillation (Aqua solis) project set out to demonstrate that the technology of trough-type solar concentration plants is mature enough to be applied in relatively low-technology countries. The idea was to find applications of the Sixth Framework Programme -funded 'Self-sufficient renewable energy air-conditioning system for Mediterranean countries' (REACT) project, beyond heat and refrigeration. The technical feasibility of the proposed applications was not the focus, but rather the quantitative assessment of their potential economical and environmental benefits as compared to existing solutions. Thus, the aim of this Specific Support Action (SSA) was to perform a complete feasibility study in order to investigate the possible applications of the REACT system in certain areas. The main possibilities considered by the project related to clean water production by processes such as solar distillation, atmospheric condensation and waste processing. Aqua solis discovered that the technology used in such plants can be used to generate fresh water without additional costs for equipment. Also, this could be realised at times when there is an availability of excess energy that would otherwise be lost. Project partners conducted simulations of the proposed technologies, paying special attention to the generality of the system being investigated, with less regard for in-depth accuracy. Study results showed that fresh water obtained from atmospheric humidity or from desalination using solar concentrating plants can be used to store solar energy and transform it into a useful product. The Aqua solis approach showed it was possible to use small-size plants for small communities where fresh water is a by-product of a multipurpose approach. Future testing with real multi-generative plants is necessary to verify the economic gains that the Aqua solis study indicated are possible. Further work is also needed to better understand the economic and technical implications of producing fresh water from solar concentrating plants. Furthermore, Aqua solis proposed that careful assessments be conducted regarding the safety of distilled water for human consumption. Overall, project outcomes indicated that the diffusion of plants that can produce water as an additional economic output to heating and cooling may be regarded as a boost for renewable energy. This has the potential to kick-start the diffusion of solar energy in Mediterranean countries.
