NOVELTY - Solar thermal energy production involves, in the daytime operation, feeding heat energy by solar thermal power to a solar liquid, taking off some part of solar liquid heated in feeding, storing remaining solar liquid heated in feeding in storage device, and displaying colder solar liquid from storage device, and in nighttime operation, adding same solar liquid in daytime operation which is present into storage device in such a manner that heated solar liquid is displaced from storage device and is withdrawn as heating medium.    USE - For solar thermal energy production in which switching between daytime and nighttime operation is possible; for producing pure water from raw water; and for producing drinking water and/or service water from salt water or contaminated water (claimed).    ADVANTAGE - The process is simple and efficient process for producing energy from solar radiation, which process makes minor requirements of the location, particularly with respect to space requirement and available water quality; permits integration in a simple manner into other processes for diverse fields of use, particularly for producing drinking water or service water; does not require either complex and expensive crude-water pretreatment or high capital expenditure; and is suitable for use in remote areas or in developing countries. The device can be manufactured with inexpensive materials but nevertheless be reliable in operation and insensitive to fouling or scaling.    DETAILED DESCRIPTION - Solar thermal energy production in which switching between daytime and nighttime operation is possible, involves, in the daytime operation, feeding heat energy by solar thermal power to a solar liquid which is continuously present and is heated, taking off a part of the solar liquid heated in the feeding as heating medium, storing a remaining part of the solar liquid heated in the feeding in a storage device, and displaying a colder solar liquid from the storage device by the part of the heated solar liquid that is to be stored, and, in the nighttime operation, introducing the same solar liquid in the daytime operation which is continuously present into the storage device in such a manner that the heated solar liquid obtained in the storing is displaced from the storage device and is withdrawn as heating medium. INDEPENDENT CLAIMS are included for the following:    (1) a continuous process for producing pure water from raw water, involving passing a raw water comprising a non-vaporizable component as cooling medium into a heat exchanger, additionally supplying heat, to the raw water heated in the heat exchanger, feeding the raw water from the supplying to an evaporation zone, contacting a carrier gas suitable for water vapor in the evaporation zone with the raw water in countercurrent, where the carrier gas takes up water vapor from the raw water to obtain a water vapor-loaded carrier gas, enriching the raw water obtained in the contacting in the non-vaporizable component, and withdrawing the raw water from the evaporation zone, feeding the water vapor-loaded carrier gas from the evaporation zone to the heat exchanger and cooling in countercurrent to the raw water, where the water vapor present in the carrier gas is in part condensed out, passing out of the heat charger the carrier gas depleted in water vapor, and taking off from the heat exchanger as pure water the water vapor that is condensed; and    (2) a device, comprising an appliance for feeding a solar liquid, a solar collector (4) comprising a heat-insulating covering (3) which is permeable to solar radiation, a solar heat store (9), a heat-insulating appliance (5) which separates the solar collector and the solar heat store from one another, and an appliance for withdrawing the heated solar liquid, where the solar collector is arranged directly above the solar heat store.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a device.    Covering (3)    Solar collector (4)    Heat-insulating appliance (5)    Feed line for provided solar liquid (7)    Solar heat store (8)