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Achieving solar produced electricity at a reasonable price with large utility-size units is a worldwide goal. This can be achieved by high efficiency systems and hardware cost reduction. The ORMAT Brayton cycle solar hybrid gas turbine is a step in this direction. ORMAT took part in several solar projects in which it contributed to the “solarization” of the complete power block. This paper describes the main tasks involved in solarization, and includes experimental test results where helicopter turboshaft gas turbines were used. The paper reviews several solar projects and mainly the SOLGATE project during the years 2001–2003. During 2002–2003 the turbine was operated in Spain, combined with three volumetric receivers. The initial goal of achieving 800°C at the receiver outlet was achieved and is reported on below. The successful tests have encouraged the continuation of work using gas turbines of 10 MW and above, which has already commenced.

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The concentration of waste waters using evaporators, alone or in combination with reverse-osmosis or electrodialysis plants, solar ponds, or spray dryers, to recover valuable chemicals or to reduce disposal problems is rapidly becoming a basic requirement in many industries. [ I ] [2].Typical applications are the concentration of coolingtower blowdowns, radio-active wastes, pulp and paper industry liquors, and effluents from coal gasification and liquification and other chemical processing plants.The optimal choice of process or combination of processes is dictated for each case by technical and economic factors, the most important of which are the quantity and composition of the waste-water stream, the availability and relative costs of various types of energy (electric power, steam, etc.), and the relative capital investment associated with each process.Evaporation-type concentrators offer, vis-a-vis other concentrators, the advantage of high recovery rates (up to 99.5-percent distillate recovery, meaning a 200-to-one volume reduction), lower susceptibility to feed contamination and hence minimal feed pre-treatment, and the production of a high-purity distillate (5 to 10 mg/liter TDS. In most cases, e.g., where there is a need for boiler-feed and/or coolingtower makeups, this distilled water represents a costsharing by-product, improving overall economics. A novel line of evaporative concentrators, introduced by Israel Desalination Engineering Ltd. (IDE), which utilizes low-temperature, horizontal-tube, falling-film evaporative-condensers in combination with seed slurry recirculation, offers these features at significantly reduced capital and energy costs. The improved economics enable applying these low-temperature concentrators also in cases where energy costs and solar-pond evaporation rates would normally preclude the use of evaporators.These economics will be demonstrated in this paper through examination of four possible low-temperature concentrator schemes operating on power station coolingtower blowdown. TECHNOLOGYIn horizontal-tube, falling-film evaporative-condensers the waste stream is sprayed on top of a bundle of horizontal tubes, flows in thin films over the external surface of these tubes, and is partially evaporated due to the transfer of latent heat released by vapor condensing inside the tubes.Latent heat transfer (meaning no loss of driving force due to sensible heating) assures all falling film evaporators, including vertical tube evaporators (VTE), high thermody- The advantage of horizontal-tube evaporators (HTE) over VTE plants lies in the greater simplicity and higher reliability of their brine-distribution system. The VTE plants require an individual distributor for each vertical tube, and clogging of this distributor by dirt or scale can affect the flow pattern along the whole tube and create problematic dry spots.These potential problems are avoided in HTE plants through common distribution of the liquid films over the entire horizontal-tube bundle and through proper spraynozzle and sp...