In South of EU tourism is a main business on which up to 90% of employment depends on. Tourism requires ca. 300 Litres/pers./day of drinking water. The areas where most of the hotel resorts and secondary facilities are located scare on potable water. The available source of water is sea and groundwater which has to be desalinated too. Hotels and restaurants are mainly local SME business. Due to the high demand of potable water there is a threat to this increasing industry. SoA technology to desalinate water is Reverse Osmosis, which is expensive in invest and operation and due to the high electrical energy consumption not environmental friendly. The proposing SMEs have come together to develop DeSol as innovative, environmental friendly and efficient process that desalinates water using thermal energy at a low level which will be provided by solar collectors. The low temperature level of evaporation could be achieved through processing at vacuum pressure. Vacuum is generated through the water column in the effluent formed by the gravity of the condensed water. DeSol will be a highly competitive product with significant technological features: Evaporation at temperature of 60deg.C in a vacuum atmosphere generated by the gravity of effluent water column; Raw water charged by a maintenance free pump combining a piston pump with a directly coupled Stirling motor; Modular design for flexible adaptation to low or high capacities required by customers; Control and adjustment by hydro-thermo-mechanical systems to achieve energy efficiency of up to 92%. The system will be cost-efficient, save investment and energy, easy to be operated and designed for low maintenance efforts at a long life time. Innovation barriers have to be overcome to realise the self-adjusting the water column generating the vacuum; Pump driven by direct coupled