Abstract: A heat-transfer medium is heated by a solar heat collector and then adiabatically compressed. The heat-transfer medium thus compressed exchanges heat with the seawater to heat it, and is then adiabatically expanded with the heated seawater being evaporated and the steam thus produced, upon heat exchange with the seawater, changed into fresh water.

Abstract: A desalinazation apparatus has the bulk of its piping circuitry composed of black iron pipe, or similar pipe, which is normally subject to corrosion by sea water. Heat transfer to a salt water still includes indirect heat transfer by a thermal oil which is contained in the black iron pipe. A solar collector heat source is used to heat the heat transfer oil. The heat transfer rate from the heat transfer oil is maintained by using turbulence inducing fins in the interior of the heat transfer tubes in the salt water still and by directing high pressure gas at the exterior of the heat transfer tubes in the salt water still. A manifold of jets placed beneath the heat transfer tubes in the salt water still projects the high pressure gas, such as high pressure high temperature steam, onto the exterior of the heat exchange tubes.