Abstract: An installation for producing solar thermal energy includes a floating thermal storage water heater provided with an absorber layer on the inside thereof and with transparent thermal insulation on the upper surface thereof. Solar rays penetrate the transparent thermal insulation and are converted into heat in the absorber layer. Heat is used to warm the water in the thermal storage water heater. The heated water can be removed in the form of a heat-carrying fluid and can, for instance, be used to provide electricity and drinking water using a steam generator, a turbo group and a condenser. Water that flows back out of the steam generator can initially be directed into a warm water recirculation heater in order to minimize heat loss. The thermal storage water heater is embedded in the warm water recirculation heater. Preferably, both storage devices are designed in such a way that their volumes can be modified.