Tel Aviv (Jan. 27)
— A team of scientists at Ben Gurion University in Beersheba headed by Prof. Yirmiyahu Branover, an immigrant from the Soviet Union, is preparing to start construction of a commercial model of a new machine for the conversion of solar energy into electric power through the use of liquid metals. A demonstration model has been successfully tested and work on the commercial equipment, due to start within two months, should be completed within about two years.
Branover started his research into magneto hydrodynamics– the science of the motion of fluids through magnetic fields– in Riga in the 1960s, continuing it when he came to Israel about 10 years ago.
His system uses a liquid metal such as a sodium potassium alloy which circulates through a solar collector and heats up rapidly. It is then mixed with droplets of a volatile liquid which vaporizes and expands, driving the liquid metal through the magnetic field. The current is picked up by electrodes. The vapor and the metal are then separated, with the metal being re-cycled through the solar collector and the vapor condensed in a tank to produce hot water as a by-product for use in the home or factory.
According to Branover, the new system requires only low heat sources to heat it and geothermal water or waste industrial heat can replace the solar collectors. It is also flexible in its applications.
“It can be used as an autonomous system to supply electricity and heat the water of an apartment block, or the power it generates can be fed directly into the grid,” he says.
HIGH ENERGY EFFICIENCY
The Branover system has an overall energy efficiency of 12-15 percent, a third higher than any other system, with very little heat lost from the liquid metal. It is the first time that metal rather than oil or water has been used in a solar collector.
Branover estimates that once the system is mass-produced the cost of a 10 kilowatt unit will be about $10,000 and a 100-kilowatt unit $70,000 with a life of about 30 years, requiring virtually no repair or maintenance. Electricity can be sold for about five-and-a-half cents per kilowatt-hour, about half of the present cost in Israel.
Production costs for the first industrial model, about $2.5 million, are being provided by the Dutchbased Solmecs Investment Company which has been active in other Israeli energy projects.