Founded in 1999, AIGUASOL provides engineering and research services, promoting innovative solutions to reduce the impact associated to energy consumption. Providing an integrated vision, the services AIGUASOL provide focus exclusively in the field of energy systems. AIGUASOL distributes TRNSYS in Spain and Portugal. Together with CSTB, Aiguasol has developed TRANSOL - a software tool for the design of solar systems. TRANSOL 2.1 focuses on Solar Thermal Systems and brings dynamic calculation accuracy of TRNSYS 16 (TRANsient simulation SYStems) closer to users. Through a user-friendly interface, designers can choose between a wide range of solar thermal schemes (including multi-dwelling systems), for different applications (DHW, Heating and Pool) and run simulations to predict the future system behaviour. TRANSOL allows optimising different elements on the system: orientation and inclination of solar panels, tank volumes, insulation thickness, flows, etc. with the powerful TRNSYS engine. The software includes meteorological data for 500 locations in Europe (Meteonorm database).