duct 20 which thus constitutes a fluid outlet depicted by arrows on the right of the central ducts in fig2 oil stored in a reservoir 32 is pumped by a pump 33 to an oil heater 34 and the heated oil is injected into the liquid ring fluid inlet shown as 22 in fig2 any oil that exits from the liquid outlet 21 of the turbine is allowed to replenish the oil in the reservoir 32 steam exiting from the fluid outlet 20 of the turbine enters an external steam condenser 35 wherein steam is introduced at high pressure into a fluid inlet thereof a source of cold water such as cooling tower 36 sprays cold water by means of a pump 37 into the condenser 35 thereby condensing the steam exiting from the fluid outlet 20 of the turbine the water in the condenser becomes heated owing to the condensation of steam and is pumped back to the cooling tower 36 by a pump 38 where the heat is dissipated to the atmosphere the condenser 35 must operate under very low pressure in order to ensure efficient condensation in order to preserve low air pressure any gases that enter the condenser 35 and cannot be condensed are removed by a vacuum pump 39 in a preferred embodiment the liquid ring is formed of a type of oil that is denser than water and immiscible therewith and may be maintained at a higher temperature than the steam in order to avoid steam condensation on the liquid ring since the working fluid.